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linux-7.2.3/fs/ecryptfs/Kconfig

@@ -0,0 +1,23 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config ECRYPT_FS
+	tristate "eCrypt filesystem layer support"
+	depends on KEYS && CRYPTO && (ENCRYPTED_KEYS || ENCRYPTED_KEYS=n)
+	select CRYPTO_ECB
+	select CRYPTO_CBC
+	select CRYPTO_LIB_MD5
+	help
+	  Encrypted filesystem that operates on the VFS layer.  See
+	  <file:Documentation/filesystems/ecryptfs.rst> to learn more about
+	  eCryptfs.  Userspace components are required and can be
+	  obtained from <http://ecryptfs.sf.net>.
+
+	  To compile this file system support as a module, choose M here: the
+	  module will be called ecryptfs.
+
+config ECRYPT_FS_MESSAGING
+	bool "Enable notifications for userspace key wrap/unwrap"
+	depends on ECRYPT_FS
+	help
+	  Enables the /dev/ecryptfs entry for use by ecryptfsd. This allows
+	  for userspace to wrap/unwrap file encryption keys by other
+	  backends, like OpenSSL.

linux-7.2.3/fs/ecryptfs/Makefile

@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for the Linux eCryptfs
+#
+
+obj-$(CONFIG_ECRYPT_FS) += ecryptfs.o
+
+ecryptfs-y := dentry.o file.o inode.o main.o super.o mmap.o read_write.o \
+	      crypto.o keystore.o kthread.o debug.o
+
+ecryptfs-$(CONFIG_ECRYPT_FS_MESSAGING) += messaging.o miscdev.o

linux-7.2.3/fs/ecryptfs/debug.c

@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ * Functions only useful for debugging.
+ *
+ * Copyright (C) 2006 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ */
+
+#include <linux/string.h>
+#include "ecryptfs_kernel.h"
+
+/*
+ * ecryptfs_dump_auth_tok - debug function to print auth toks
+ *
+ * This function will print the contents of an ecryptfs authentication
+ * token.
+ */
+void ecryptfs_dump_auth_tok(struct ecryptfs_auth_tok *auth_tok)
+{
+	char salt[ECRYPTFS_SALT_SIZE * 2 + 1];
+	char sig[ECRYPTFS_SIG_SIZE_HEX + 1];
+
+	ecryptfs_printk(KERN_DEBUG, "Auth tok at mem loc [%p]:\n",
+			auth_tok);
+	if (auth_tok->flags & ECRYPTFS_PRIVATE_KEY) {
+		ecryptfs_printk(KERN_DEBUG, " * private key type\n");
+	} else {
+		ecryptfs_printk(KERN_DEBUG, " * passphrase type\n");
+		ecryptfs_to_hex(salt, auth_tok->token.password.salt,
+				ECRYPTFS_SALT_SIZE);
+		ecryptfs_printk(KERN_DEBUG, " * salt = [%s]\n", salt);
+		if (auth_tok->token.password.flags &
+		    ECRYPTFS_PERSISTENT_PASSWORD) {
+			ecryptfs_printk(KERN_DEBUG, " * persistent\n");
+		}
+		strscpy(sig, auth_tok->token.password.signature);
+		ecryptfs_printk(KERN_DEBUG, " * signature = [%s]\n", sig);
+	}
+	ecryptfs_printk(KERN_DEBUG, " * session_key.flags = [0x%x]\n",
+			auth_tok->session_key.flags);
+	if (auth_tok->session_key.flags
+	    & ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT)
+		ecryptfs_printk(KERN_DEBUG,
+				" * Userspace decrypt request set\n");
+	if (auth_tok->session_key.flags
+	    & ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT)
+		ecryptfs_printk(KERN_DEBUG,
+				" * Userspace encrypt request set\n");
+	if (auth_tok->session_key.flags & ECRYPTFS_CONTAINS_DECRYPTED_KEY) {
+		ecryptfs_printk(KERN_DEBUG, " * Contains decrypted key\n");
+		ecryptfs_printk(KERN_DEBUG,
+				" * session_key.decrypted_key_size = [0x%x]\n",
+				auth_tok->session_key.decrypted_key_size);
+		ecryptfs_printk(KERN_DEBUG, " * Decrypted session key "
+				"dump:\n");
+		if (ecryptfs_verbosity > 0)
+			ecryptfs_dump_hex(auth_tok->session_key.decrypted_key,
+					  ECRYPTFS_DEFAULT_KEY_BYTES);
+	}
+	if (auth_tok->session_key.flags & ECRYPTFS_CONTAINS_ENCRYPTED_KEY) {
+		ecryptfs_printk(KERN_DEBUG, " * Contains encrypted key\n");
+		ecryptfs_printk(KERN_DEBUG,
+				" * session_key.encrypted_key_size = [0x%x]\n",
+				auth_tok->session_key.encrypted_key_size);
+		ecryptfs_printk(KERN_DEBUG, " * Encrypted session key "
+				"dump:\n");
+		if (ecryptfs_verbosity > 0)
+			ecryptfs_dump_hex(auth_tok->session_key.encrypted_key,
+					  auth_tok->session_key.
+					  encrypted_key_size);
+	}
+}
+
+/**
+ * ecryptfs_dump_hex - debug hex printer
+ * @data: string of bytes to be printed
+ * @bytes: number of bytes to print
+ *
+ * Dump hexadecimal representation of char array
+ */
+void ecryptfs_dump_hex(char *data, int bytes)
+{
+	if (ecryptfs_verbosity < 1)
+		return;
+
+	print_hex_dump(KERN_DEBUG, "ecryptfs: ", DUMP_PREFIX_OFFSET, 16, 1,
+		       data, bytes, false);
+}

linux-7.2.3/fs/ecryptfs/dentry.c

@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 1997-2003 Erez Zadok
+ * Copyright (C) 2001-2003 Stony Brook University
+ * Copyright (C) 2004-2006 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ */
+
+#include <linux/dcache.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+#include <linux/fs_stack.h>
+#include <linux/slab.h>
+#include "ecryptfs_kernel.h"
+
+/**
+ * ecryptfs_d_revalidate - revalidate an ecryptfs dentry
+ * @dir: inode of expected parent
+ * @name: expected name
+ * @dentry: dentry to revalidate
+ * @flags: lookup flags
+ *
+ * Called when the VFS needs to revalidate a dentry. This
+ * is called whenever a name lookup finds a dentry in the
+ * dcache. Most filesystems leave this as NULL, because all their
+ * dentries in the dcache are valid.
+ *
+ * Returns 1 if valid, 0 otherwise.
+ *
+ */
+static int ecryptfs_d_revalidate(struct inode *dir, const struct qstr *name,
+				 struct dentry *dentry, unsigned int flags)
+{
+	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	int rc = 1;
+
+	if (flags & LOOKUP_RCU)
+		return -ECHILD;
+
+	if (lower_dentry->d_flags & DCACHE_OP_REVALIDATE) {
+		struct inode *lower_dir = ecryptfs_inode_to_lower(dir);
+		struct name_snapshot n;
+
+		take_dentry_name_snapshot(&n, lower_dentry);
+		rc = lower_dentry->d_op->d_revalidate(lower_dir, &n.name,
+						      lower_dentry, flags);
+		release_dentry_name_snapshot(&n);
+	}
+
+	if (d_really_is_positive(dentry)) {
+		struct inode *inode = d_inode(dentry);
+
+		fsstack_copy_attr_all(inode, ecryptfs_inode_to_lower(inode));
+		if (!inode->i_nlink)
+			return 0;
+	}
+	return rc;
+}
+
+/**
+ * ecryptfs_d_release
+ * @dentry: The ecryptfs dentry
+ *
+ * Called when a dentry is really deallocated.
+ */
+static void ecryptfs_d_release(struct dentry *dentry)
+{
+	dput(dentry->d_fsdata);
+}
+
+const struct dentry_operations ecryptfs_dops = {
+	.d_revalidate = ecryptfs_d_revalidate,
+	.d_release = ecryptfs_d_release,
+};

linux-7.2.3/fs/ecryptfs/ecryptfs_kernel.h

@@ -0,0 +1,696 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/**
+ * eCryptfs: Linux filesystem encryption layer
+ * Kernel declarations.
+ *
+ * Copyright (C) 1997-2003 Erez Zadok
+ * Copyright (C) 2001-2003 Stony Brook University
+ * Copyright (C) 2004-2008 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ *              Trevor S. Highland <trevor.highland@gmail.com>
+ *              Tyler Hicks <code@tyhicks.com>
+ */
+
+#ifndef ECRYPTFS_KERNEL_H
+#define ECRYPTFS_KERNEL_H
+
+#include <crypto/md5.h>
+#include <crypto/skcipher.h>
+#include <keys/user-type.h>
+#include <keys/encrypted-type.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/fs_stack.h>
+#include <linux/hex.h>
+#include <linux/namei.h>
+#include <linux/scatterlist.h>
+#include <linux/hash.h>
+#include <linux/nsproxy.h>
+#include <linux/backing-dev.h>
+#include <linux/ecryptfs.h>
+
+#define ECRYPTFS_DEFAULT_IV_BYTES 16
+#define ECRYPTFS_DEFAULT_EXTENT_SIZE 4096
+#define ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE 8192
+#define ECRYPTFS_DEFAULT_MSG_CTX_ELEMS 32
+#define ECRYPTFS_DEFAULT_SEND_TIMEOUT HZ
+#define ECRYPTFS_MAX_MSG_CTX_TTL (HZ*3)
+#define ECRYPTFS_DEFAULT_NUM_USERS 4
+#define ECRYPTFS_MAX_NUM_USERS 32768
+#define ECRYPTFS_XATTR_NAME "user.ecryptfs"
+
+void ecryptfs_dump_auth_tok(struct ecryptfs_auth_tok *auth_tok);
+static inline void
+ecryptfs_to_hex(char *dst, char *src, size_t src_size)
+{
+	char *end = bin2hex(dst, src, src_size);
+	*end = '\0';
+}
+
+extern void ecryptfs_from_hex(char *dst, char *src, int dst_size);
+
+struct ecryptfs_key_record {
+	unsigned char type;
+	size_t enc_key_size;
+	unsigned char sig[ECRYPTFS_SIG_SIZE];
+	unsigned char enc_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES];
+};
+
+struct ecryptfs_auth_tok_list {
+	struct ecryptfs_auth_tok *auth_tok;
+	struct list_head list;
+};
+
+struct ecryptfs_crypt_stat;
+struct ecryptfs_mount_crypt_stat;
+
+struct ecryptfs_page_crypt_context {
+	struct page *page;
+#define ECRYPTFS_PREPARE_COMMIT_MODE 0
+#define ECRYPTFS_WRITEPAGE_MODE      1
+	unsigned int mode;
+	union {
+		struct file *lower_file;
+		struct writeback_control *wbc;
+	} param;
+};
+
+#if defined(CONFIG_ENCRYPTED_KEYS) || defined(CONFIG_ENCRYPTED_KEYS_MODULE)
+static inline struct ecryptfs_auth_tok *
+ecryptfs_get_encrypted_key_payload_data(struct key *key)
+{
+	struct encrypted_key_payload *payload;
+
+	if (key->type != &key_type_encrypted)
+		return NULL;
+
+	payload = key->payload.data[0];
+	if (!payload)
+		return ERR_PTR(-EKEYREVOKED);
+
+	return (struct ecryptfs_auth_tok *)payload->payload_data;
+}
+
+static inline struct key *ecryptfs_get_encrypted_key(char *sig)
+{
+	return request_key(&key_type_encrypted, sig, NULL);
+}
+
+#else
+static inline struct ecryptfs_auth_tok *
+ecryptfs_get_encrypted_key_payload_data(struct key *key)
+{
+	return NULL;
+}
+
+static inline struct key *ecryptfs_get_encrypted_key(char *sig)
+{
+	return ERR_PTR(-ENOKEY);
+}
+
+#endif /* CONFIG_ENCRYPTED_KEYS */
+
+static inline struct ecryptfs_auth_tok *
+ecryptfs_get_key_payload_data(struct key *key)
+{
+	struct ecryptfs_auth_tok *auth_tok;
+	struct user_key_payload *ukp;
+
+	auth_tok = ecryptfs_get_encrypted_key_payload_data(key);
+	if (auth_tok)
+		return auth_tok;
+
+	ukp = user_key_payload_locked(key);
+	if (!ukp)
+		return ERR_PTR(-EKEYREVOKED);
+
+	return (struct ecryptfs_auth_tok *)ukp->data;
+}
+
+#define ECRYPTFS_MAX_KEYSET_SIZE 1024
+#define ECRYPTFS_MAX_CIPHER_NAME_SIZE 31
+#define ECRYPTFS_MAX_NUM_ENC_KEYS 64
+#define ECRYPTFS_MAX_IV_BYTES 16	/* 128 bits */
+#define ECRYPTFS_SALT_BYTES 2
+#define MAGIC_ECRYPTFS_MARKER 0x3c81b7f5
+#define MAGIC_ECRYPTFS_MARKER_SIZE_BYTES 8	/* 4*2 */
+#define ECRYPTFS_FILE_SIZE_BYTES (sizeof(u64))
+#define ECRYPTFS_SIZE_AND_MARKER_BYTES (ECRYPTFS_FILE_SIZE_BYTES \
+					+ MAGIC_ECRYPTFS_MARKER_SIZE_BYTES)
+#define ECRYPTFS_DEFAULT_CIPHER "aes"
+#define ECRYPTFS_DEFAULT_KEY_BYTES 16
+#define ECRYPTFS_TAG_1_PACKET_TYPE 0x01
+#define ECRYPTFS_TAG_3_PACKET_TYPE 0x8C
+#define ECRYPTFS_TAG_11_PACKET_TYPE 0xED
+#define ECRYPTFS_TAG_64_PACKET_TYPE 0x40
+#define ECRYPTFS_TAG_65_PACKET_TYPE 0x41
+#define ECRYPTFS_TAG_66_PACKET_TYPE 0x42
+#define ECRYPTFS_TAG_67_PACKET_TYPE 0x43
+#define ECRYPTFS_TAG_70_PACKET_TYPE 0x46 /* FNEK-encrypted filename
+					  * as dentry name */
+#define ECRYPTFS_TAG_71_PACKET_TYPE 0x47 /* FNEK-encrypted filename in
+					  * metadata */
+#define ECRYPTFS_TAG_72_PACKET_TYPE 0x48 /* FEK-encrypted filename as
+					  * dentry name */
+#define ECRYPTFS_TAG_73_PACKET_TYPE 0x49 /* FEK-encrypted filename as
+					  * metadata */
+#define ECRYPTFS_MIN_PKT_LEN_SIZE 1 /* Min size to specify packet length */
+#define ECRYPTFS_MAX_PKT_LEN_SIZE 2 /* Pass at least this many bytes to
+				     * ecryptfs_parse_packet_length() and
+				     * ecryptfs_write_packet_length()
+				     */
+/* Constraint: ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES >=
+ * ECRYPTFS_MAX_IV_BYTES */
+#define ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 16
+#define ECRYPTFS_NON_NULL 0x42 /* A reasonable substitute for NULL */
+#define ECRYPTFS_TAG_70_MIN_METADATA_SIZE (1 + ECRYPTFS_MIN_PKT_LEN_SIZE \
+					   + ECRYPTFS_SIG_SIZE + 1 + 1)
+#define ECRYPTFS_TAG_70_MAX_METADATA_SIZE (1 + ECRYPTFS_MAX_PKT_LEN_SIZE \
+					   + ECRYPTFS_SIG_SIZE + 1 + 1)
+#define ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX "ECRYPTFS_FEK_ENCRYPTED."
+#define ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE 23
+#define ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX "ECRYPTFS_FNEK_ENCRYPTED."
+#define ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE 24
+#define ECRYPTFS_ENCRYPTED_DENTRY_NAME_LEN (18 + 1 + 4 + 1 + 32)
+
+#ifdef CONFIG_ECRYPT_FS_MESSAGING
+# define ECRYPTFS_VERSIONING_MASK_MESSAGING (ECRYPTFS_VERSIONING_DEVMISC \
+					     | ECRYPTFS_VERSIONING_PUBKEY)
+#else
+# define ECRYPTFS_VERSIONING_MASK_MESSAGING 0
+#endif
+
+#define ECRYPTFS_VERSIONING_MASK (ECRYPTFS_VERSIONING_PASSPHRASE \
+				  | ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH \
+				  | ECRYPTFS_VERSIONING_XATTR \
+				  | ECRYPTFS_VERSIONING_MULTKEY \
+				  | ECRYPTFS_VERSIONING_MASK_MESSAGING \
+				  | ECRYPTFS_VERSIONING_FILENAME_ENCRYPTION)
+struct ecryptfs_key_sig {
+	struct list_head crypt_stat_list;
+	char keysig[ECRYPTFS_SIG_SIZE_HEX + 1];
+};
+
+struct ecryptfs_filename {
+	struct list_head crypt_stat_list;
+#define ECRYPTFS_FILENAME_CONTAINS_DECRYPTED 0x00000001
+	u32 flags;
+	u32 seq_no;
+	char *filename;
+	char *encrypted_filename;
+	size_t filename_size;
+	size_t encrypted_filename_size;
+	char fnek_sig[ECRYPTFS_SIG_SIZE_HEX];
+	char dentry_name[ECRYPTFS_ENCRYPTED_DENTRY_NAME_LEN + 1];
+};
+
+/**
+ * This is the primary struct associated with each encrypted file.
+ *
+ * TODO: cache align/pack?
+ */
+struct ecryptfs_crypt_stat {
+#define ECRYPTFS_STRUCT_INITIALIZED   0x00000001
+#define ECRYPTFS_POLICY_APPLIED       0x00000002
+#define ECRYPTFS_ENCRYPTED            0x00000004
+#define ECRYPTFS_SECURITY_WARNING     0x00000008
+#define ECRYPTFS_ENABLE_HMAC          0x00000010
+#define ECRYPTFS_ENCRYPT_IV_PAGES     0x00000020
+#define ECRYPTFS_KEY_VALID            0x00000040
+#define ECRYPTFS_METADATA_IN_XATTR    0x00000080
+#define ECRYPTFS_VIEW_AS_ENCRYPTED    0x00000100
+#define ECRYPTFS_KEY_SET              0x00000200
+#define ECRYPTFS_ENCRYPT_FILENAMES    0x00000400
+#define ECRYPTFS_ENCFN_USE_MOUNT_FNEK 0x00000800
+#define ECRYPTFS_ENCFN_USE_FEK        0x00001000
+#define ECRYPTFS_UNLINK_SIGS          0x00002000
+#define ECRYPTFS_I_SIZE_INITIALIZED   0x00004000
+	u32 flags;
+	unsigned int file_version;
+	size_t iv_bytes;
+	size_t metadata_size;
+	size_t extent_size; /* Data extent size; default is 4096 */
+	size_t key_size;
+	size_t extent_shift;
+	unsigned int extent_mask;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
+	struct crypto_skcipher *tfm;
+	unsigned char cipher[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
+	unsigned char key[ECRYPTFS_MAX_KEY_BYTES];
+	unsigned char root_iv[ECRYPTFS_MAX_IV_BYTES];
+	struct list_head keysig_list;
+	struct mutex keysig_list_mutex;
+	struct mutex cs_tfm_mutex;
+	struct mutex cs_mutex;
+};
+
+/* inode private data. */
+struct ecryptfs_inode_info {
+	struct inode vfs_inode;
+	struct inode *wii_inode;
+	struct mutex lower_file_mutex;
+	atomic_t lower_file_count;
+	struct file *lower_file;
+	struct ecryptfs_crypt_stat crypt_stat;
+};
+
+/**
+ * ecryptfs_global_auth_tok - A key used to encrypt all new files under the mountpoint
+ * @flags: Status flags
+ * @mount_crypt_stat_list: These auth_toks hang off the mount-wide
+ *                         cryptographic context. Every time a new
+ *                         inode comes into existence, eCryptfs copies
+ *                         the auth_toks on that list to the set of
+ *                         auth_toks on the inode's crypt_stat
+ * @global_auth_tok_key: The key from the user's keyring for the sig
+ * @global_auth_tok: The key contents
+ * @sig: The key identifier
+ *
+ * ecryptfs_global_auth_tok structs refer to authentication token keys
+ * in the user keyring that apply to newly created files. A list of
+ * these objects hangs off of the mount_crypt_stat struct for any
+ * given eCryptfs mount. This struct maintains a reference to both the
+ * key contents and the key itself so that the key can be put on
+ * unmount.
+ */
+struct ecryptfs_global_auth_tok {
+#define ECRYPTFS_AUTH_TOK_INVALID 0x00000001
+#define ECRYPTFS_AUTH_TOK_FNEK    0x00000002
+	u32 flags;
+	struct list_head mount_crypt_stat_list;
+	struct key *global_auth_tok_key;
+	unsigned char sig[ECRYPTFS_SIG_SIZE_HEX + 1];
+};
+
+/**
+ * ecryptfs_key_tfm - Persistent key tfm
+ * @key_tfm: crypto API handle to the key
+ * @key_size: Key size in bytes
+ * @key_tfm_mutex: Mutex to ensure only one operation in eCryptfs is
+ *                 using the persistent TFM at any point in time
+ * @key_tfm_list: Handle to hang this off the module-wide TFM list
+ * @cipher_name: String name for the cipher for this TFM
+ *
+ * Typically, eCryptfs will use the same ciphers repeatedly throughout
+ * the course of its operations. In order to avoid unnecessarily
+ * destroying and initializing the same cipher repeatedly, eCryptfs
+ * keeps a list of crypto API contexts around to use when needed.
+ */
+struct ecryptfs_key_tfm {
+	struct crypto_skcipher *key_tfm;
+	size_t key_size;
+	struct mutex key_tfm_mutex;
+	struct list_head key_tfm_list;
+	unsigned char cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
+};
+
+extern struct mutex key_tfm_list_mutex;
+
+/**
+ * This struct is to enable a mount-wide passphrase/salt combo. This
+ * is more or less a stopgap to provide similar functionality to other
+ * crypto filesystems like EncFS or CFS until full policy support is
+ * implemented in eCryptfs.
+ */
+struct ecryptfs_mount_crypt_stat {
+	/* Pointers to memory we do not own, do not free these */
+#define ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED 0x00000001
+#define ECRYPTFS_XATTR_METADATA_ENABLED        0x00000002
+#define ECRYPTFS_ENCRYPTED_VIEW_ENABLED        0x00000004
+#define ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED  0x00000008
+#define ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES      0x00000010
+#define ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK   0x00000020
+#define ECRYPTFS_GLOBAL_ENCFN_USE_FEK          0x00000040
+#define ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY    0x00000080
+	u32 flags;
+	struct list_head global_auth_tok_list;
+	struct mutex global_auth_tok_list_mutex;
+	size_t global_default_cipher_key_size;
+	size_t global_default_fn_cipher_key_bytes;
+	unsigned char global_default_cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE
+						 + 1];
+	unsigned char global_default_fn_cipher_name[
+		ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
+	char global_default_fnek_sig[ECRYPTFS_SIG_SIZE_HEX + 1];
+};
+
+/* superblock private data. */
+struct ecryptfs_sb_info {
+	struct super_block *wsi_sb;
+	struct vfsmount *lower_mnt;
+	struct ecryptfs_mount_crypt_stat mount_crypt_stat;
+};
+
+/* file private data. */
+struct ecryptfs_file_info {
+	struct file *wfi_file;
+	struct ecryptfs_crypt_stat *crypt_stat;
+};
+
+/* auth_tok <=> encrypted_session_key mappings */
+struct ecryptfs_auth_tok_list_item {
+	unsigned char encrypted_session_key[ECRYPTFS_MAX_KEY_BYTES];
+	struct list_head list;
+	struct ecryptfs_auth_tok auth_tok;
+};
+
+struct ecryptfs_message {
+	/* Can never be greater than ecryptfs_message_buf_len */
+	/* Used to find the parent msg_ctx */
+	/* Inherits from msg_ctx->index */
+	u32 index;
+	u32 data_len;
+	u8 data[] __counted_by(data_len);
+};
+
+struct ecryptfs_msg_ctx {
+#define ECRYPTFS_MSG_CTX_STATE_FREE     0x01
+#define ECRYPTFS_MSG_CTX_STATE_PENDING  0x02
+#define ECRYPTFS_MSG_CTX_STATE_DONE     0x03
+#define ECRYPTFS_MSG_CTX_STATE_NO_REPLY 0x04
+	u8 state;
+#define ECRYPTFS_MSG_HELO 100
+#define ECRYPTFS_MSG_QUIT 101
+#define ECRYPTFS_MSG_REQUEST 102
+#define ECRYPTFS_MSG_RESPONSE 103
+	u8 type;
+	u32 index;
+	/* Counter converts to a sequence number. Each message sent
+	 * out for which we expect a response has an associated
+	 * sequence number. The response must have the same sequence
+	 * number as the counter for the msg_stc for the message to be
+	 * valid. */
+	u32 counter;
+	size_t msg_size;
+	struct ecryptfs_message *msg;
+	struct task_struct *task;
+	struct list_head node;
+	struct list_head daemon_out_list;
+	struct mutex mux;
+};
+
+struct ecryptfs_daemon {
+#define ECRYPTFS_DAEMON_IN_READ      0x00000001
+#define ECRYPTFS_DAEMON_IN_POLL      0x00000002
+#define ECRYPTFS_DAEMON_ZOMBIE       0x00000004
+#define ECRYPTFS_DAEMON_MISCDEV_OPEN 0x00000008
+	u32 flags;
+	u32 num_queued_msg_ctx;
+	struct file *file;
+	struct mutex mux;
+	struct list_head msg_ctx_out_queue;
+	wait_queue_head_t wait;
+	struct hlist_node euid_chain;
+};
+
+#ifdef CONFIG_ECRYPT_FS_MESSAGING
+extern struct mutex ecryptfs_daemon_hash_mux;
+#endif
+
+static inline size_t
+ecryptfs_lower_header_size(struct ecryptfs_crypt_stat *crypt_stat)
+{
+	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
+		return 0;
+	return crypt_stat->metadata_size;
+}
+
+static inline struct ecryptfs_file_info *
+ecryptfs_file_to_private(struct file *file)
+{
+	return file->private_data;
+}
+
+static inline void
+ecryptfs_set_file_private(struct file *file,
+			  struct ecryptfs_file_info *file_info)
+{
+	file->private_data = file_info;
+}
+
+static inline struct file *ecryptfs_file_to_lower(struct file *file)
+{
+	return ((struct ecryptfs_file_info *)file->private_data)->wfi_file;
+}
+
+static inline void
+ecryptfs_set_file_lower(struct file *file, struct file *lower_file)
+{
+	((struct ecryptfs_file_info *)file->private_data)->wfi_file =
+		lower_file;
+}
+
+static inline struct ecryptfs_inode_info *
+ecryptfs_inode_to_private(struct inode *inode)
+{
+	return container_of(inode, struct ecryptfs_inode_info, vfs_inode);
+}
+
+static inline struct inode *ecryptfs_inode_to_lower(struct inode *inode)
+{
+	return ecryptfs_inode_to_private(inode)->wii_inode;
+}
+
+static inline void
+ecryptfs_set_inode_lower(struct inode *inode, struct inode *lower_inode)
+{
+	ecryptfs_inode_to_private(inode)->wii_inode = lower_inode;
+}
+
+static inline struct ecryptfs_sb_info *
+ecryptfs_superblock_to_private(struct super_block *sb)
+{
+	return (struct ecryptfs_sb_info *)sb->s_fs_info;
+}
+
+static inline void
+ecryptfs_set_superblock_private(struct super_block *sb,
+				struct ecryptfs_sb_info *sb_info)
+{
+	sb->s_fs_info = sb_info;
+}
+
+static inline struct super_block *
+ecryptfs_superblock_to_lower(struct super_block *sb)
+{
+	return ((struct ecryptfs_sb_info *)sb->s_fs_info)->wsi_sb;
+}
+
+static inline void
+ecryptfs_set_superblock_lower(struct super_block *sb,
+			      struct super_block *lower_sb)
+{
+	((struct ecryptfs_sb_info *)sb->s_fs_info)->wsi_sb = lower_sb;
+}
+
+static inline void
+ecryptfs_set_dentry_lower(struct dentry *dentry,
+			  struct dentry *lower_dentry)
+{
+	dentry->d_fsdata = lower_dentry;
+}
+
+static inline struct dentry *
+ecryptfs_dentry_to_lower(struct dentry *dentry)
+{
+	return dentry->d_fsdata;
+}
+
+static inline struct path
+ecryptfs_lower_path(struct dentry *dentry)
+{
+	return (struct path){
+		.mnt = ecryptfs_superblock_to_private(dentry->d_sb)->lower_mnt,
+		.dentry = ecryptfs_dentry_to_lower(dentry)
+	};
+}
+
+#define ecryptfs_printk(type, fmt, arg...) \
+        __ecryptfs_printk(type "%s: " fmt, __func__, ## arg)
+__printf(1, 2)
+void __ecryptfs_printk(const char *fmt, ...);
+
+extern const struct file_operations ecryptfs_main_fops;
+extern const struct file_operations ecryptfs_dir_fops;
+extern const struct inode_operations ecryptfs_main_iops;
+extern const struct inode_operations ecryptfs_dir_iops;
+extern const struct inode_operations ecryptfs_symlink_iops;
+extern const struct super_operations ecryptfs_sops;
+extern const struct dentry_operations ecryptfs_dops;
+extern const struct address_space_operations ecryptfs_aops;
+extern int ecryptfs_verbosity;
+extern unsigned int ecryptfs_message_buf_len;
+extern signed long ecryptfs_message_wait_timeout;
+extern unsigned int ecryptfs_number_of_users;
+
+extern struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
+extern struct kmem_cache *ecryptfs_file_info_cache;
+extern struct kmem_cache *ecryptfs_inode_info_cache;
+extern struct kmem_cache *ecryptfs_sb_info_cache;
+extern struct kmem_cache *ecryptfs_header_cache;
+extern struct kmem_cache *ecryptfs_xattr_cache;
+extern struct kmem_cache *ecryptfs_key_record_cache;
+extern struct kmem_cache *ecryptfs_key_sig_cache;
+extern struct kmem_cache *ecryptfs_global_auth_tok_cache;
+extern struct kmem_cache *ecryptfs_key_tfm_cache;
+
+struct inode *ecryptfs_get_inode(struct inode *lower_inode,
+				 struct super_block *sb);
+void ecryptfs_i_size_init(const char *page_virt, struct inode *inode);
+int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
+			     struct inode *ecryptfs_inode);
+int ecryptfs_decode_and_decrypt_filename(char **decrypted_name,
+					 size_t *decrypted_name_size,
+					 struct super_block *sb,
+					 const char *name, size_t name_size);
+int ecryptfs_encrypt_and_encode_filename(
+	char **encoded_name,
+	size_t *encoded_name_size,
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
+	const char *name, size_t name_size);
+void ecryptfs_dump_hex(char *data, int bytes);
+int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
+			int sg_size);
+int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat);
+void ecryptfs_rotate_iv(unsigned char *iv);
+void ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat);
+void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat);
+void ecryptfs_destroy_mount_crypt_stat(
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat);
+int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat);
+int ecryptfs_write_inode_size_to_metadata(struct inode *ecryptfs_inode);
+int ecryptfs_encrypt_page(struct folio *folio);
+int ecryptfs_decrypt_page(struct folio *folio);
+int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
+			    struct inode *ecryptfs_inode);
+int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry);
+int ecryptfs_new_file_context(struct inode *ecryptfs_inode);
+void ecryptfs_write_crypt_stat_flags(char *page_virt,
+				     struct ecryptfs_crypt_stat *crypt_stat,
+				     size_t *written);
+int ecryptfs_read_and_validate_header_region(struct inode *inode);
+int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
+					    struct inode *inode);
+u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes);
+int ecryptfs_cipher_code_to_string(char *str, size_t size, u8 cipher_code);
+void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat);
+int ecryptfs_generate_key_packet_set(char *dest_base,
+				     struct ecryptfs_crypt_stat *crypt_stat,
+				     struct dentry *ecryptfs_dentry,
+				     size_t *len, size_t max);
+int
+ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
+			  unsigned char *src, struct dentry *ecryptfs_dentry);
+int ecryptfs_truncate(struct dentry *dentry, loff_t new_length);
+ssize_t
+ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
+			const char *name, void *value, size_t size);
+int
+ecryptfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name,
+		  const void *value, size_t size, int flags);
+int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode);
+#ifdef CONFIG_ECRYPT_FS_MESSAGING
+int ecryptfs_process_response(struct ecryptfs_daemon *daemon,
+			      struct ecryptfs_message *msg, u32 seq);
+int ecryptfs_send_message(char *data, int data_len,
+			  struct ecryptfs_msg_ctx **msg_ctx);
+int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx,
+			       struct ecryptfs_message **emsg);
+int ecryptfs_init_messaging(void);
+void ecryptfs_release_messaging(void);
+#else
+static inline int ecryptfs_init_messaging(void)
+{
+	return 0;
+}
+static inline void ecryptfs_release_messaging(void)
+{ }
+static inline int ecryptfs_send_message(char *data, int data_len,
+					struct ecryptfs_msg_ctx **msg_ctx)
+{
+	return -ENOTCONN;
+}
+static inline int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx,
+					     struct ecryptfs_message **emsg)
+{
+	return -ENOMSG;
+}
+#endif
+
+void
+ecryptfs_write_header_metadata(char *virt,
+			       struct ecryptfs_crypt_stat *crypt_stat,
+			       size_t *written);
+int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig);
+int
+ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
+			   char *sig, u32 global_auth_tok_flags);
+int ecryptfs_get_global_auth_tok_for_sig(
+	struct ecryptfs_global_auth_tok **global_auth_tok,
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig);
+int
+ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
+			 size_t key_size);
+int ecryptfs_init_crypto(void);
+int ecryptfs_destroy_crypto(void);
+int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm);
+int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_skcipher **tfm,
+					       struct mutex **tfm_mutex,
+					       char *cipher_name);
+int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
+				      struct ecryptfs_auth_tok **auth_tok,
+				      char *sig);
+int ecryptfs_write_lower(struct inode *ecryptfs_inode, char *data,
+			 loff_t offset, size_t size);
+int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode,
+				      struct folio *folio_for_lower,
+				      size_t offset_in_page, size_t size);
+int ecryptfs_write(struct inode *inode, char *data, loff_t offset, size_t size);
+int ecryptfs_read_lower(char *data, loff_t offset, size_t size,
+			struct inode *ecryptfs_inode);
+int ecryptfs_read_lower_page_segment(struct folio *folio_for_ecryptfs,
+				     pgoff_t page_index,
+				     size_t offset_in_page, size_t size,
+				     struct inode *ecryptfs_inode);
+int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
+				 size_t *length_size);
+int ecryptfs_write_packet_length(char *dest, size_t size,
+				 size_t *packet_size_length);
+#ifdef CONFIG_ECRYPT_FS_MESSAGING
+int ecryptfs_init_ecryptfs_miscdev(void);
+void ecryptfs_destroy_ecryptfs_miscdev(void);
+int ecryptfs_send_miscdev(char *data, size_t data_size,
+			  struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type,
+			  u16 msg_flags, struct ecryptfs_daemon *daemon);
+void ecryptfs_msg_ctx_alloc_to_free(struct ecryptfs_msg_ctx *msg_ctx);
+int
+ecryptfs_spawn_daemon(struct ecryptfs_daemon **daemon, struct file *file);
+int ecryptfs_exorcise_daemon(struct ecryptfs_daemon *daemon);
+int ecryptfs_find_daemon_by_euid(struct ecryptfs_daemon **daemon);
+#endif
+int ecryptfs_init_kthread(void);
+void ecryptfs_destroy_kthread(void);
+int ecryptfs_privileged_open(struct file **lower_file,
+			     struct dentry *lower_dentry,
+			     struct vfsmount *lower_mnt,
+			     const struct cred *cred);
+int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode);
+void ecryptfs_put_lower_file(struct inode *inode);
+int
+ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
+			     size_t *packet_size,
+			     struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
+			     char *filename, size_t filename_size);
+int
+ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
+			     size_t *packet_size,
+			     struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
+			     char *data, size_t max_packet_size);
+int ecryptfs_set_f_namelen(long *namelen, long lower_namelen,
+			   struct ecryptfs_mount_crypt_stat *mount_crypt_stat);
+void ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
+			loff_t offset);
+
+extern const struct xattr_handler * const ecryptfs_xattr_handlers[];
+
+#endif /* #ifndef ECRYPTFS_KERNEL_H */

linux-7.2.3/fs/ecryptfs/file.c

@@ -0,0 +1,442 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 1997-2004 Erez Zadok
+ * Copyright (C) 2001-2004 Stony Brook University
+ * Copyright (C) 2004-2007 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
+ *   		Michael C. Thompson <mcthomps@us.ibm.com>
+ */
+
+#include <linux/file.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/mount.h>
+#include <linux/pagemap.h>
+#include <linux/security.h>
+#include <linux/compat.h>
+#include <linux/fs_stack.h>
+#include "ecryptfs_kernel.h"
+
+/*
+ * ecryptfs_read_update_atime
+ *
+ * generic_file_read updates the atime of upper layer inode.  But, it
+ * doesn't give us a chance to update the atime of the lower layer
+ * inode.  This function is a wrapper to generic_file_read.  It
+ * updates the atime of the lower level inode if generic_file_read
+ * returns without any errors. This is to be used only for file reads.
+ * The function to be used for directory reads is ecryptfs_read.
+ */
+static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
+				struct iov_iter *to)
+{
+	ssize_t rc;
+	struct file *file = iocb->ki_filp;
+
+	rc = generic_file_read_iter(iocb, to);
+	if (rc >= 0) {
+		struct path path = ecryptfs_lower_path(file->f_path.dentry);
+		touch_atime(&path);
+	}
+	return rc;
+}
+
+/*
+ * ecryptfs_splice_read_update_atime
+ *
+ * filemap_splice_read updates the atime of upper layer inode.  But, it
+ * doesn't give us a chance to update the atime of the lower layer inode.  This
+ * function is a wrapper to generic_file_read.  It updates the atime of the
+ * lower level inode if generic_file_read returns without any errors. This is
+ * to be used only for file reads.  The function to be used for directory reads
+ * is ecryptfs_read.
+ */
+static ssize_t ecryptfs_splice_read_update_atime(struct file *in, loff_t *ppos,
+						 struct pipe_inode_info *pipe,
+						 size_t len, unsigned int flags)
+{
+	ssize_t rc;
+
+	rc = filemap_splice_read(in, ppos, pipe, len, flags);
+	if (rc >= 0) {
+		struct path path = ecryptfs_lower_path(in->f_path.dentry);
+		touch_atime(&path);
+	}
+	return rc;
+}
+
+struct ecryptfs_getdents_callback {
+	struct dir_context ctx;
+	struct dir_context *caller;
+	struct super_block *sb;
+	int filldir_called;
+	int entries_written;
+};
+
+/* Inspired by generic filldir in fs/readdir.c */
+static bool
+ecryptfs_filldir(struct dir_context *ctx, const char *lower_name,
+		 int lower_namelen, loff_t offset, u64 ino, unsigned int d_type)
+{
+	struct ecryptfs_getdents_callback *buf =
+		container_of(ctx, struct ecryptfs_getdents_callback, ctx);
+	size_t name_size;
+	char *name;
+	int err;
+	bool res;
+
+	buf->filldir_called++;
+	err = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
+						   buf->sb, lower_name,
+						   lower_namelen);
+	if (err) {
+		if (err != -EINVAL) {
+			ecryptfs_printk(KERN_DEBUG,
+					"%s: Error attempting to decode and decrypt filename [%s]; rc = [%d]\n",
+					__func__, lower_name, err);
+			return false;
+		}
+
+		/* Mask -EINVAL errors as these are most likely due a plaintext
+		 * filename present in the lower filesystem despite filename
+		 * encryption being enabled. One unavoidable example would be
+		 * the "lost+found" dentry in the root directory of an Ext4
+		 * filesystem.
+		 */
+		return true;
+	}
+
+	buf->caller->pos = buf->ctx.pos;
+	res = dir_emit(buf->caller, name, name_size, ino, d_type);
+	kfree(name);
+	if (res)
+		buf->entries_written++;
+	return res;
+}
+
+/**
+ * ecryptfs_readdir
+ * @file: The eCryptfs directory file
+ * @ctx: The actor to feed the entries to
+ */
+static int ecryptfs_readdir(struct file *file, struct dir_context *ctx)
+{
+	int rc;
+	struct file *lower_file;
+	struct inode *inode = file_inode(file);
+	struct ecryptfs_getdents_callback buf = {
+		.ctx.actor = ecryptfs_filldir,
+		.caller = ctx,
+		.sb = inode->i_sb,
+	};
+	lower_file = ecryptfs_file_to_lower(file);
+	rc = iterate_dir(lower_file, &buf.ctx);
+	ctx->pos = buf.ctx.pos;
+	if (rc >= 0 && (buf.entries_written || !buf.filldir_called))
+		fsstack_copy_attr_atime(inode, file_inode(lower_file));
+	return rc;
+}
+
+struct kmem_cache *ecryptfs_file_info_cache;
+
+static int read_or_initialize_metadata(struct dentry *dentry)
+{
+	struct inode *inode = d_inode(dentry);
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
+	struct ecryptfs_crypt_stat *crypt_stat;
+	int rc;
+
+	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
+	mount_crypt_stat = &ecryptfs_superblock_to_private(
+						inode->i_sb)->mount_crypt_stat;
+	mutex_lock(&crypt_stat->cs_mutex);
+
+	if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
+	    crypt_stat->flags & ECRYPTFS_KEY_VALID) {
+		rc = 0;
+		goto out;
+	}
+
+	rc = ecryptfs_read_metadata(dentry);
+	if (!rc)
+		goto out;
+
+	if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
+		crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
+				       | ECRYPTFS_ENCRYPTED);
+		rc = 0;
+		goto out;
+	}
+
+	if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
+	    !i_size_read(ecryptfs_inode_to_lower(inode))) {
+		rc = ecryptfs_initialize_file(dentry, inode);
+		if (!rc)
+			goto out;
+	}
+
+	rc = -EIO;
+out:
+	mutex_unlock(&crypt_stat->cs_mutex);
+	return rc;
+}
+
+static int ecryptfs_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct file *lower_file = ecryptfs_file_to_lower(file);
+	/*
+	 * Don't allow mmap on top of file systems that don't support it
+	 * natively.  If FILESYSTEM_MAX_STACK_DEPTH > 2 or ecryptfs
+	 * allows recursive mounting, this will need to be extended.
+	 */
+	if (!can_mmap_file(lower_file))
+		return -ENODEV;
+	return generic_file_mmap(file, vma);
+}
+
+/**
+ * ecryptfs_open
+ * @inode: inode specifying file to open
+ * @file: Structure to return filled in
+ *
+ * Opens the file specified by inode.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_open(struct inode *inode, struct file *file)
+{
+	int rc = 0;
+	struct ecryptfs_crypt_stat *crypt_stat = NULL;
+	struct dentry *ecryptfs_dentry = file->f_path.dentry;
+	/* Private value of ecryptfs_dentry allocated in
+	 * ecryptfs_lookup() */
+	struct ecryptfs_file_info *file_info;
+
+	/* Released in ecryptfs_release or end of function if failure */
+	file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
+	ecryptfs_set_file_private(file, file_info);
+	if (!file_info) {
+		ecryptfs_printk(KERN_ERR,
+				"Error attempting to allocate memory\n");
+		rc = -ENOMEM;
+		goto out;
+	}
+	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
+	mutex_lock(&crypt_stat->cs_mutex);
+	if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
+		ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
+		/* Policy code enabled in future release */
+		crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
+				      | ECRYPTFS_ENCRYPTED);
+	}
+	mutex_unlock(&crypt_stat->cs_mutex);
+	rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
+	if (rc) {
+		printk(KERN_ERR "%s: Error attempting to initialize "
+			"the lower file for the dentry with name "
+			"[%pd]; rc = [%d]\n", __func__,
+			ecryptfs_dentry, rc);
+		goto out_free;
+	}
+	if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
+	    == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
+		rc = -EPERM;
+		printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
+		       "file must hence be opened RO\n", __func__);
+		goto out_put;
+	}
+	ecryptfs_set_file_lower(
+		file, ecryptfs_inode_to_private(inode)->lower_file);
+	rc = read_or_initialize_metadata(ecryptfs_dentry);
+	if (rc)
+		goto out_put;
+	ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
+			"[0x%.16llx] size: [0x%.16llx]\n", inode, inode->i_ino,
+			(unsigned long long)i_size_read(inode));
+	goto out;
+out_put:
+	ecryptfs_put_lower_file(inode);
+out_free:
+	kmem_cache_free(ecryptfs_file_info_cache,
+			ecryptfs_file_to_private(file));
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_dir_open
+ * @inode: inode specifying file to open
+ * @file: Structure to return filled in
+ *
+ * Opens the file specified by inode.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_dir_open(struct inode *inode, struct file *file)
+{
+	struct dentry *ecryptfs_dentry = file->f_path.dentry;
+	/* Private value of ecryptfs_dentry allocated in
+	 * ecryptfs_lookup() */
+	struct ecryptfs_file_info *file_info;
+	struct file *lower_file;
+	struct path path;
+
+	/* Released in ecryptfs_release or end of function if failure */
+	file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
+	ecryptfs_set_file_private(file, file_info);
+	if (unlikely(!file_info)) {
+		ecryptfs_printk(KERN_ERR,
+				"Error attempting to allocate memory\n");
+		return -ENOMEM;
+	}
+	path = ecryptfs_lower_path(ecryptfs_dentry);
+	lower_file = dentry_open(&path, file->f_flags, current_cred());
+	if (IS_ERR(lower_file)) {
+		printk(KERN_ERR "%s: Error attempting to initialize "
+			"the lower file for the dentry with name "
+			"[%pd]; rc = [%ld]\n", __func__,
+			ecryptfs_dentry, PTR_ERR(lower_file));
+		kmem_cache_free(ecryptfs_file_info_cache, file_info);
+		return PTR_ERR(lower_file);
+	}
+	ecryptfs_set_file_lower(file, lower_file);
+	return 0;
+}
+
+static int ecryptfs_flush(struct file *file, fl_owner_t td)
+{
+	struct file *lower_file = ecryptfs_file_to_lower(file);
+
+	if (lower_file->f_op->flush) {
+		filemap_write_and_wait(file->f_mapping);
+		return lower_file->f_op->flush(lower_file, td);
+	}
+
+	return 0;
+}
+
+static int ecryptfs_release(struct inode *inode, struct file *file)
+{
+	ecryptfs_put_lower_file(inode);
+	kmem_cache_free(ecryptfs_file_info_cache,
+			ecryptfs_file_to_private(file));
+	return 0;
+}
+
+static int ecryptfs_dir_release(struct inode *inode, struct file *file)
+{
+	fput(ecryptfs_file_to_lower(file));
+	kmem_cache_free(ecryptfs_file_info_cache,
+			ecryptfs_file_to_private(file));
+	return 0;
+}
+
+static loff_t ecryptfs_dir_llseek(struct file *file, loff_t offset, int whence)
+{
+	return vfs_llseek(ecryptfs_file_to_lower(file), offset, whence);
+}
+
+static int
+ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
+{
+	int rc;
+
+	rc = file_write_and_wait(file);
+	if (rc)
+		return rc;
+
+	return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
+}
+
+static int ecryptfs_fasync(int fd, struct file *file, int flag)
+{
+	int rc = 0;
+	struct file *lower_file = NULL;
+
+	lower_file = ecryptfs_file_to_lower(file);
+	if (lower_file->f_op->fasync)
+		rc = lower_file->f_op->fasync(fd, lower_file, flag);
+	return rc;
+}
+
+static long
+ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct file *lower_file = ecryptfs_file_to_lower(file);
+	long rc = -ENOTTY;
+
+	if (!lower_file->f_op->unlocked_ioctl)
+		return rc;
+
+	switch (cmd) {
+	case FITRIM:
+	case FS_IOC_GETFLAGS:
+	case FS_IOC_SETFLAGS:
+	case FS_IOC_GETVERSION:
+	case FS_IOC_SETVERSION:
+		rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
+		fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
+
+		return rc;
+	default:
+		return rc;
+	}
+}
+
+#ifdef CONFIG_COMPAT
+static long
+ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct file *lower_file = ecryptfs_file_to_lower(file);
+	long rc = -ENOIOCTLCMD;
+
+	if (!lower_file->f_op->compat_ioctl)
+		return rc;
+
+	switch (cmd) {
+	case FITRIM:
+	case FS_IOC32_GETFLAGS:
+	case FS_IOC32_SETFLAGS:
+	case FS_IOC32_GETVERSION:
+	case FS_IOC32_SETVERSION:
+		rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
+		fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
+
+		return rc;
+	default:
+		return rc;
+	}
+}
+#endif
+
+const struct file_operations ecryptfs_dir_fops = {
+	.iterate_shared = ecryptfs_readdir,
+	.read = generic_read_dir,
+	.unlocked_ioctl = ecryptfs_unlocked_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = ecryptfs_compat_ioctl,
+#endif
+	.open = ecryptfs_dir_open,
+	.release = ecryptfs_dir_release,
+	.fsync = ecryptfs_fsync,
+	.llseek = ecryptfs_dir_llseek,
+};
+
+const struct file_operations ecryptfs_main_fops = {
+	.llseek = generic_file_llseek,
+	.read_iter = ecryptfs_read_update_atime,
+	.write_iter = generic_file_write_iter,
+	.unlocked_ioctl = ecryptfs_unlocked_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = ecryptfs_compat_ioctl,
+#endif
+	.mmap = ecryptfs_mmap,
+	.open = ecryptfs_open,
+	.flush = ecryptfs_flush,
+	.release = ecryptfs_release,
+	.fsync = ecryptfs_fsync,
+	.fasync = ecryptfs_fasync,
+	.splice_read = ecryptfs_splice_read_update_atime,
+};

linux-7.2.3/fs/ecryptfs/kthread.c

@@ -0,0 +1,159 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 2008 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ */
+
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/mount.h>
+#include "ecryptfs_kernel.h"
+
+struct ecryptfs_open_req {
+	struct file **lower_file;
+	struct path path;
+	struct completion done;
+	struct list_head kthread_ctl_list;
+};
+
+static struct ecryptfs_kthread_ctl {
+#define ECRYPTFS_KTHREAD_ZOMBIE 0x00000001
+	u32 flags;
+	struct mutex mux;
+	struct list_head req_list;
+	wait_queue_head_t wait;
+} ecryptfs_kthread_ctl;
+
+static struct task_struct *ecryptfs_kthread;
+
+/**
+ * ecryptfs_threadfn
+ * @ignored: ignored
+ *
+ * The eCryptfs kernel thread that has the responsibility of getting
+ * the lower file with RW permissions.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_threadfn(void *ignored)
+{
+	set_freezable();
+	while (1)  {
+		struct ecryptfs_open_req *req;
+
+		wait_event_freezable(
+			ecryptfs_kthread_ctl.wait,
+			(!list_empty(&ecryptfs_kthread_ctl.req_list)
+			 || kthread_should_stop()));
+		mutex_lock(&ecryptfs_kthread_ctl.mux);
+		if (ecryptfs_kthread_ctl.flags & ECRYPTFS_KTHREAD_ZOMBIE) {
+			mutex_unlock(&ecryptfs_kthread_ctl.mux);
+			goto out;
+		}
+		while (!list_empty(&ecryptfs_kthread_ctl.req_list)) {
+			req = list_first_entry(&ecryptfs_kthread_ctl.req_list,
+					       struct ecryptfs_open_req,
+					       kthread_ctl_list);
+			list_del(&req->kthread_ctl_list);
+			*req->lower_file = dentry_open(&req->path,
+				(O_RDWR | O_LARGEFILE), current_cred());
+			complete(&req->done);
+		}
+		mutex_unlock(&ecryptfs_kthread_ctl.mux);
+	}
+out:
+	return 0;
+}
+
+int __init ecryptfs_init_kthread(void)
+{
+	int rc = 0;
+
+	mutex_init(&ecryptfs_kthread_ctl.mux);
+	init_waitqueue_head(&ecryptfs_kthread_ctl.wait);
+	INIT_LIST_HEAD(&ecryptfs_kthread_ctl.req_list);
+	ecryptfs_kthread = kthread_run(&ecryptfs_threadfn, NULL,
+				       "ecryptfs-kthread");
+	if (IS_ERR(ecryptfs_kthread)) {
+		rc = PTR_ERR(ecryptfs_kthread);
+		printk(KERN_ERR "%s: Failed to create kernel thread; rc = [%d]"
+		       "\n", __func__, rc);
+	}
+	return rc;
+}
+
+void ecryptfs_destroy_kthread(void)
+{
+	struct ecryptfs_open_req *req, *tmp;
+
+	mutex_lock(&ecryptfs_kthread_ctl.mux);
+	ecryptfs_kthread_ctl.flags |= ECRYPTFS_KTHREAD_ZOMBIE;
+	list_for_each_entry_safe(req, tmp, &ecryptfs_kthread_ctl.req_list,
+				 kthread_ctl_list) {
+		list_del(&req->kthread_ctl_list);
+		*req->lower_file = ERR_PTR(-EIO);
+		complete(&req->done);
+	}
+	mutex_unlock(&ecryptfs_kthread_ctl.mux);
+	kthread_stop(ecryptfs_kthread);
+	wake_up(&ecryptfs_kthread_ctl.wait);
+}
+
+/**
+ * ecryptfs_privileged_open
+ * @lower_file: Result of dentry_open by root on lower dentry
+ * @lower_dentry: Lower dentry for file to open
+ * @lower_mnt: Lower vfsmount for file to open
+ * @cred: credential to use for this call
+ *
+ * This function gets a r/w file opened against the lower dentry.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_privileged_open(struct file **lower_file,
+			     struct dentry *lower_dentry,
+			     struct vfsmount *lower_mnt,
+			     const struct cred *cred)
+{
+	struct ecryptfs_open_req req;
+	int flags = O_LARGEFILE;
+	int rc = 0;
+
+	init_completion(&req.done);
+	req.lower_file = lower_file;
+	req.path.dentry = lower_dentry;
+	req.path.mnt = lower_mnt;
+
+	/* Corresponding dput() and mntput() are done when the
+	 * lower file is fput() when all eCryptfs files for the inode are
+	 * released. */
+	flags |= IS_RDONLY(d_inode(lower_dentry)) ? O_RDONLY : O_RDWR;
+	(*lower_file) = dentry_open(&req.path, flags, cred);
+	if (!IS_ERR(*lower_file))
+		goto out;
+	if ((flags & O_ACCMODE) == O_RDONLY) {
+		rc = PTR_ERR((*lower_file));
+		goto out;
+	}
+	mutex_lock(&ecryptfs_kthread_ctl.mux);
+	if (ecryptfs_kthread_ctl.flags & ECRYPTFS_KTHREAD_ZOMBIE) {
+		rc = -EIO;
+		mutex_unlock(&ecryptfs_kthread_ctl.mux);
+		printk(KERN_ERR "%s: We are in the middle of shutting down; "
+		       "aborting privileged request to open lower file\n",
+			__func__);
+		goto out;
+	}
+	list_add_tail(&req.kthread_ctl_list, &ecryptfs_kthread_ctl.req_list);
+	mutex_unlock(&ecryptfs_kthread_ctl.mux);
+	wake_up(&ecryptfs_kthread_ctl.wait);
+	wait_for_completion(&req.done);
+	if (IS_ERR(*lower_file))
+		rc = PTR_ERR(*lower_file);
+out:
+	return rc;
+}

linux-7.2.3/fs/ecryptfs/main.c

@@ -0,0 +1,895 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 1997-2003 Erez Zadok
+ * Copyright (C) 2001-2003 Stony Brook University
+ * Copyright (C) 2004-2007 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ *              Michael C. Thompson <mcthomps@us.ibm.com>
+ *              Tyler Hicks <code@tyhicks.com>
+ */
+
+#include <linux/dcache.h>
+#include <linux/file.h>
+#include <linux/fips.h>
+#include <linux/module.h>
+#include <linux/namei.h>
+#include <linux/skbuff.h>
+#include <linux/pagemap.h>
+#include <linux/key.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
+#include <linux/fs_stack.h>
+#include <linux/sysfs.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/magic.h>
+#include "ecryptfs_kernel.h"
+
+/*
+ * Module parameter that defines the ecryptfs_verbosity level.
+ */
+int ecryptfs_verbosity = 0;
+
+module_param(ecryptfs_verbosity, int, 0);
+MODULE_PARM_DESC(ecryptfs_verbosity,
+		 "Initial verbosity level (0 or 1; defaults to "
+		 "0, which is Quiet)");
+
+/*
+ * Module parameter that defines the number of message buffer elements
+ */
+unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
+
+module_param(ecryptfs_message_buf_len, uint, 0);
+MODULE_PARM_DESC(ecryptfs_message_buf_len,
+		 "Number of message buffer elements");
+
+/*
+ * Module parameter that defines the maximum guaranteed amount of time to wait
+ * for a response from ecryptfsd.  The actual sleep time will be, more than
+ * likely, a small amount greater than this specified value, but only less if
+ * the message successfully arrives.
+ */
+signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
+
+module_param(ecryptfs_message_wait_timeout, long, 0);
+MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
+		 "Maximum number of seconds that an operation will "
+		 "sleep while waiting for a message response from "
+		 "userspace");
+
+/*
+ * Module parameter that is an estimate of the maximum number of users
+ * that will be concurrently using eCryptfs. Set this to the right
+ * value to balance performance and memory use.
+ */
+unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
+
+module_param(ecryptfs_number_of_users, uint, 0);
+MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
+		 "concurrent users of eCryptfs");
+
+void __ecryptfs_printk(const char *fmt, ...)
+{
+	va_list args;
+	va_start(args, fmt);
+	if (fmt[1] == '7') { /* KERN_DEBUG */
+		if (ecryptfs_verbosity >= 1)
+			vprintk(fmt, args);
+	} else
+		vprintk(fmt, args);
+	va_end(args);
+}
+
+/*
+ * ecryptfs_init_lower_file
+ * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
+ *                   the lower dentry and the lower mount set
+ *
+ * eCryptfs only ever keeps a single open file for every lower
+ * inode. All I/O operations to the lower inode occur through that
+ * file. When the first eCryptfs dentry that interposes with the first
+ * lower dentry for that inode is created, this function creates the
+ * lower file struct and associates it with the eCryptfs
+ * inode. When all eCryptfs files associated with the inode are released, the
+ * file is closed.
+ *
+ * The lower file will be opened with read/write permissions, if
+ * possible. Otherwise, it is opened read-only.
+ *
+ * This function does nothing if a lower file is already
+ * associated with the eCryptfs inode.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_init_lower_file(struct dentry *dentry,
+				    struct file **lower_file)
+{
+	const struct cred *cred = current_cred();
+	struct path path = ecryptfs_lower_path(dentry);
+	int rc;
+
+	rc = ecryptfs_privileged_open(lower_file, path.dentry, path.mnt, cred);
+	if (rc) {
+		printk(KERN_ERR "Error opening lower file "
+		       "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
+		       "rc = [%d]\n", path.dentry, path.mnt, rc);
+		(*lower_file) = NULL;
+	}
+	return rc;
+}
+
+int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
+{
+	struct ecryptfs_inode_info *inode_info;
+	int count, rc = 0;
+
+	inode_info = ecryptfs_inode_to_private(inode);
+	mutex_lock(&inode_info->lower_file_mutex);
+	count = atomic_inc_return(&inode_info->lower_file_count);
+	if (WARN_ON_ONCE(count < 1))
+		rc = -EINVAL;
+	else if (count == 1) {
+		rc = ecryptfs_init_lower_file(dentry,
+					      &inode_info->lower_file);
+		if (rc)
+			atomic_set(&inode_info->lower_file_count, 0);
+	}
+	mutex_unlock(&inode_info->lower_file_mutex);
+	return rc;
+}
+
+void ecryptfs_put_lower_file(struct inode *inode)
+{
+	struct ecryptfs_inode_info *inode_info;
+
+	inode_info = ecryptfs_inode_to_private(inode);
+	if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
+				      &inode_info->lower_file_mutex)) {
+		filemap_write_and_wait(inode->i_mapping);
+		fput(inode_info->lower_file);
+		inode_info->lower_file = NULL;
+		mutex_unlock(&inode_info->lower_file_mutex);
+	}
+}
+
+enum {
+	Opt_sig, Opt_ecryptfs_sig, Opt_cipher, Opt_ecryptfs_cipher,
+	Opt_ecryptfs_key_bytes, Opt_passthrough, Opt_xattr_metadata,
+	Opt_encrypted_view, Opt_fnek_sig, Opt_fn_cipher,
+	Opt_fn_cipher_key_bytes, Opt_unlink_sigs, Opt_mount_auth_tok_only,
+	Opt_check_dev_ruid
+};
+
+static const struct fs_parameter_spec ecryptfs_fs_param_spec[] = {
+	fsparam_string	("sig",			    Opt_sig),
+	fsparam_string	("ecryptfs_sig",	    Opt_ecryptfs_sig),
+	fsparam_string	("cipher",		    Opt_cipher),
+	fsparam_string	("ecryptfs_cipher",	    Opt_ecryptfs_cipher),
+	fsparam_u32	("ecryptfs_key_bytes",	    Opt_ecryptfs_key_bytes),
+	fsparam_flag	("ecryptfs_passthrough",    Opt_passthrough),
+	fsparam_flag	("ecryptfs_xattr_metadata", Opt_xattr_metadata),
+	fsparam_flag	("ecryptfs_encrypted_view", Opt_encrypted_view),
+	fsparam_string	("ecryptfs_fnek_sig",	    Opt_fnek_sig),
+	fsparam_string	("ecryptfs_fn_cipher",	    Opt_fn_cipher),
+	fsparam_u32	("ecryptfs_fn_key_bytes",   Opt_fn_cipher_key_bytes),
+	fsparam_flag	("ecryptfs_unlink_sigs",    Opt_unlink_sigs),
+	fsparam_flag	("ecryptfs_mount_auth_tok_only", Opt_mount_auth_tok_only),
+	fsparam_flag	("ecryptfs_check_dev_ruid", Opt_check_dev_ruid),
+	{}
+};
+
+static int ecryptfs_init_global_auth_toks(
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
+{
+	struct ecryptfs_global_auth_tok *global_auth_tok;
+	struct ecryptfs_auth_tok *auth_tok;
+	int rc = 0;
+
+	list_for_each_entry(global_auth_tok,
+			    &mount_crypt_stat->global_auth_tok_list,
+			    mount_crypt_stat_list) {
+		rc = ecryptfs_keyring_auth_tok_for_sig(
+			&global_auth_tok->global_auth_tok_key, &auth_tok,
+			global_auth_tok->sig);
+		if (rc) {
+			printk(KERN_ERR "Could not find valid key in user "
+			       "session keyring for sig specified in mount "
+			       "option: [%s]\n", global_auth_tok->sig);
+			global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
+			goto out;
+		} else {
+			global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
+			up_write(&(global_auth_tok->global_auth_tok_key)->sem);
+		}
+	}
+out:
+	return rc;
+}
+
+static void ecryptfs_init_mount_crypt_stat(
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
+{
+	memset((void *)mount_crypt_stat, 0,
+	       sizeof(struct ecryptfs_mount_crypt_stat));
+	INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
+	mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
+	mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
+}
+
+struct ecryptfs_fs_context {
+	/* Mount option status trackers */
+	bool check_ruid;
+	bool sig_set;
+	bool cipher_name_set;
+	bool cipher_key_bytes_set;
+	bool fn_cipher_name_set;
+	bool fn_cipher_key_bytes_set;
+};
+
+/**
+ * ecryptfs_parse_param
+ * @fc: The ecryptfs filesystem context
+ * @param: The mount parameter to parse
+ *
+ * The signature of the key to use must be the description of a key
+ * already in the keyring. Mounting will fail if the key can not be
+ * found.
+ *
+ * Returns zero on success; non-zero on error
+ */
+static int ecryptfs_parse_param(
+	struct fs_context *fc,
+	struct fs_parameter *param)
+{
+	int rc;
+	int opt;
+	struct fs_parse_result result;
+	struct ecryptfs_fs_context *ctx = fc->fs_private;
+	struct ecryptfs_sb_info *sbi = fc->s_fs_info;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
+		&sbi->mount_crypt_stat;
+
+	opt = fs_parse(fc, ecryptfs_fs_param_spec, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_sig:
+	case Opt_ecryptfs_sig:
+		rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
+						  param->string, 0);
+		if (rc) {
+			printk(KERN_ERR "Error attempting to register "
+			       "global sig; rc = [%d]\n", rc);
+			return rc;
+		}
+		ctx->sig_set = 1;
+		break;
+	case Opt_cipher:
+	case Opt_ecryptfs_cipher:
+		strscpy(mount_crypt_stat->global_default_cipher_name,
+			param->string);
+		ctx->cipher_name_set = 1;
+		break;
+	case Opt_ecryptfs_key_bytes:
+		mount_crypt_stat->global_default_cipher_key_size =
+			result.uint_32;
+		ctx->cipher_key_bytes_set = 1;
+		break;
+	case Opt_passthrough:
+		mount_crypt_stat->flags |=
+			ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
+		break;
+	case Opt_xattr_metadata:
+		mount_crypt_stat->flags |= ECRYPTFS_XATTR_METADATA_ENABLED;
+		break;
+	case Opt_encrypted_view:
+		mount_crypt_stat->flags |= ECRYPTFS_XATTR_METADATA_ENABLED;
+		mount_crypt_stat->flags |= ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
+		break;
+	case Opt_fnek_sig:
+		strscpy(mount_crypt_stat->global_default_fnek_sig,
+			param->string);
+		rc = ecryptfs_add_global_auth_tok(
+			mount_crypt_stat,
+			mount_crypt_stat->global_default_fnek_sig,
+			ECRYPTFS_AUTH_TOK_FNEK);
+		if (rc) {
+			printk(KERN_ERR "Error attempting to register "
+			       "global fnek sig [%s]; rc = [%d]\n",
+			       mount_crypt_stat->global_default_fnek_sig, rc);
+			return rc;
+		}
+		mount_crypt_stat->flags |=
+			(ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
+			 | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
+		break;
+	case Opt_fn_cipher:
+		strscpy(mount_crypt_stat->global_default_fn_cipher_name,
+			param->string);
+		ctx->fn_cipher_name_set = 1;
+		break;
+	case Opt_fn_cipher_key_bytes:
+		mount_crypt_stat->global_default_fn_cipher_key_bytes =
+			result.uint_32;
+		ctx->fn_cipher_key_bytes_set = 1;
+		break;
+	case Opt_unlink_sigs:
+		mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
+		break;
+	case Opt_mount_auth_tok_only:
+		mount_crypt_stat->flags |= ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
+		break;
+	case Opt_check_dev_ruid:
+		ctx->check_ruid = 1;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int ecryptfs_validate_options(struct fs_context *fc)
+{
+	int rc = 0;
+	u8 cipher_code;
+	struct ecryptfs_fs_context *ctx = fc->fs_private;
+	struct ecryptfs_sb_info *sbi = fc->s_fs_info;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
+
+
+	mount_crypt_stat = &sbi->mount_crypt_stat;
+
+	if (!ctx->sig_set) {
+		rc = -EINVAL;
+		ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
+				"auth tok signature as a mount "
+				"parameter; see the eCryptfs README\n");
+		goto out;
+	}
+	if (!ctx->cipher_name_set) {
+		int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
+
+		BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
+		strscpy(mount_crypt_stat->global_default_cipher_name,
+			ECRYPTFS_DEFAULT_CIPHER);
+	}
+	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
+	    && !ctx->fn_cipher_name_set)
+		strscpy(mount_crypt_stat->global_default_fn_cipher_name,
+			mount_crypt_stat->global_default_cipher_name);
+	if (!ctx->cipher_key_bytes_set)
+		mount_crypt_stat->global_default_cipher_key_size = 0;
+	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
+	    && !ctx->fn_cipher_key_bytes_set)
+		mount_crypt_stat->global_default_fn_cipher_key_bytes =
+			mount_crypt_stat->global_default_cipher_key_size;
+
+	cipher_code = ecryptfs_code_for_cipher_string(
+		mount_crypt_stat->global_default_cipher_name,
+		mount_crypt_stat->global_default_cipher_key_size);
+	if (!cipher_code) {
+		ecryptfs_printk(KERN_ERR,
+				"eCryptfs doesn't support cipher: %s\n",
+				mount_crypt_stat->global_default_cipher_name);
+		rc = -EINVAL;
+		goto out;
+	}
+
+	mutex_lock(&key_tfm_list_mutex);
+	if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
+				 NULL)) {
+		rc = ecryptfs_add_new_key_tfm(
+			NULL, mount_crypt_stat->global_default_cipher_name,
+			mount_crypt_stat->global_default_cipher_key_size);
+		if (rc) {
+			printk(KERN_ERR "Error attempting to initialize "
+			       "cipher with name = [%s] and key size = [%td]; "
+			       "rc = [%d]\n",
+			       mount_crypt_stat->global_default_cipher_name,
+			       mount_crypt_stat->global_default_cipher_key_size,
+			       rc);
+			rc = -EINVAL;
+			mutex_unlock(&key_tfm_list_mutex);
+			goto out;
+		}
+	}
+	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
+	    && !ecryptfs_tfm_exists(
+		    mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
+		rc = ecryptfs_add_new_key_tfm(
+			NULL, mount_crypt_stat->global_default_fn_cipher_name,
+			mount_crypt_stat->global_default_fn_cipher_key_bytes);
+		if (rc) {
+			printk(KERN_ERR "Error attempting to initialize "
+			       "cipher with name = [%s] and key size = [%td]; "
+			       "rc = [%d]\n",
+			       mount_crypt_stat->global_default_fn_cipher_name,
+			       mount_crypt_stat->global_default_fn_cipher_key_bytes,
+			       rc);
+			rc = -EINVAL;
+			mutex_unlock(&key_tfm_list_mutex);
+			goto out;
+		}
+	}
+	mutex_unlock(&key_tfm_list_mutex);
+	rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
+	if (rc)
+		printk(KERN_WARNING "One or more global auth toks could not "
+		       "properly register; rc = [%d]\n", rc);
+out:
+	return rc;
+}
+
+struct kmem_cache *ecryptfs_sb_info_cache;
+static struct file_system_type ecryptfs_fs_type;
+
+/*
+ * ecryptfs_get_tree
+ * @fc: The filesystem context
+ */
+static int ecryptfs_get_tree(struct fs_context *fc)
+{
+	struct super_block *s;
+	struct ecryptfs_fs_context *ctx = fc->fs_private;
+	struct ecryptfs_sb_info *sbi = fc->s_fs_info;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
+	const char *err = "Getting sb failed";
+	struct inode *inode;
+	struct path path;
+	int rc;
+
+	if (!fc->source) {
+		rc = -EINVAL;
+		err = "Device name cannot be null";
+		goto out;
+	}
+
+	mount_crypt_stat = &sbi->mount_crypt_stat;
+	rc = ecryptfs_validate_options(fc);
+	if (rc) {
+		err = "Error validating options";
+		goto out;
+	}
+
+	if (fips_enabled) {
+		rc = -EINVAL;
+		err = "eCryptfs support is disabled due to FIPS";
+		goto out;
+	}
+
+	s = sget_fc(fc, NULL, set_anon_super_fc);
+	if (IS_ERR(s)) {
+		rc = PTR_ERR(s);
+		goto out;
+	}
+
+	rc = super_setup_bdi(s);
+	if (rc)
+		goto out1;
+
+	ecryptfs_set_superblock_private(s, sbi);
+
+	/* ->kill_sb() will take care of sbi after that point */
+	sbi = NULL;
+	s->s_op = &ecryptfs_sops;
+	s->s_xattr = ecryptfs_xattr_handlers;
+	set_default_d_op(s, &ecryptfs_dops);
+
+	err = "Reading sb failed";
+	rc = kern_path(fc->source, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
+	if (rc) {
+		ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
+		goto out1;
+	}
+	if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
+		rc = -EINVAL;
+		printk(KERN_ERR "Mount on filesystem of type "
+			"eCryptfs explicitly disallowed due to "
+			"known incompatibilities\n");
+		goto out_free;
+	}
+
+	if (is_idmapped_mnt(path.mnt)) {
+		rc = -EINVAL;
+		printk(KERN_ERR "Mounting on idmapped mounts currently disallowed\n");
+		goto out_free;
+	}
+
+	if (ctx->check_ruid &&
+	    !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
+		rc = -EPERM;
+		printk(KERN_ERR "Mount of device (uid: %d) not owned by "
+		       "requested user (uid: %d)\n",
+			i_uid_read(d_inode(path.dentry)),
+			from_kuid(&init_user_ns, current_uid()));
+		goto out_free;
+	}
+
+	ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
+
+	/**
+	 * Set the POSIX ACL flag based on whether they're enabled in the lower
+	 * mount.
+	 */
+	s->s_flags = fc->sb_flags & ~SB_POSIXACL;
+	s->s_flags |= path.dentry->d_sb->s_flags & SB_POSIXACL;
+
+	/**
+	 * Force a read-only eCryptfs mount when:
+	 *   1) The lower mount is ro
+	 *   2) The ecryptfs_encrypted_view mount option is specified
+	 */
+	if (sb_rdonly(path.dentry->d_sb) || mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
+		s->s_flags |= SB_RDONLY;
+
+	s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
+	s->s_blocksize = path.dentry->d_sb->s_blocksize;
+	s->s_magic = ECRYPTFS_SUPER_MAGIC;
+	s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
+	s->s_time_gran = path.dentry->d_sb->s_time_gran;
+
+	rc = -EINVAL;
+	if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
+		pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
+		goto out_free;
+	}
+
+	inode = ecryptfs_get_inode(d_inode(path.dentry), s);
+	rc = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out_free;
+
+	s->s_root = d_make_root(inode);
+	if (!s->s_root) {
+		rc = -ENOMEM;
+		goto out_free;
+	}
+
+	ecryptfs_set_dentry_lower(s->s_root, path.dentry);
+	ecryptfs_superblock_to_private(s)->lower_mnt = path.mnt;
+
+	s->s_flags |= SB_ACTIVE;
+	fc->root = dget(s->s_root);
+	return 0;
+
+out_free:
+	path_put(&path);
+out1:
+	deactivate_locked_super(s);
+out:
+	if (sbi)
+		ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
+
+	printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
+	return rc;
+}
+
+/**
+ * ecryptfs_kill_block_super
+ * @sb: The ecryptfs super block
+ *
+ * Used to bring the superblock down and free the private data.
+ */
+static void ecryptfs_kill_block_super(struct super_block *sb)
+{
+	struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
+	kill_anon_super(sb);
+	if (!sb_info)
+		return;
+	mntput(sb_info->lower_mnt);
+	ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
+	kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
+}
+
+static void ecryptfs_free_fc(struct fs_context *fc)
+{
+	struct ecryptfs_fs_context *ctx = fc->fs_private;
+	struct ecryptfs_sb_info *sbi = fc->s_fs_info;
+
+	kfree(ctx);
+
+	if (sbi) {
+		ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
+		kmem_cache_free(ecryptfs_sb_info_cache, sbi);
+	}
+}
+
+static const struct fs_context_operations ecryptfs_context_ops = {
+	.free		= ecryptfs_free_fc,
+	.parse_param	= ecryptfs_parse_param,
+	.get_tree	= ecryptfs_get_tree,
+	.reconfigure	= NULL,
+};
+
+static int ecryptfs_init_fs_context(struct fs_context *fc)
+{
+	struct ecryptfs_fs_context *ctx;
+	struct ecryptfs_sb_info *sbi = NULL;
+
+	ctx = kzalloc_obj(struct ecryptfs_fs_context);
+	if (!ctx)
+		return -ENOMEM;
+	sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
+	if (!sbi) {
+		kfree(ctx);
+		ctx = NULL;
+		return -ENOMEM;
+	}
+
+	ecryptfs_init_mount_crypt_stat(&sbi->mount_crypt_stat);
+
+	fc->fs_private = ctx;
+	fc->s_fs_info = sbi;
+	fc->ops = &ecryptfs_context_ops;
+	return 0;
+}
+
+static struct file_system_type ecryptfs_fs_type = {
+	.owner = THIS_MODULE,
+	.name = "ecryptfs",
+	.init_fs_context = ecryptfs_init_fs_context,
+	.parameters = ecryptfs_fs_param_spec,
+	.kill_sb = ecryptfs_kill_block_super,
+	.fs_flags = 0
+};
+MODULE_ALIAS_FS("ecryptfs");
+
+/*
+ * inode_info_init_once
+ *
+ * Initializes the ecryptfs_inode_info_cache when it is created
+ */
+static void
+inode_info_init_once(void *vptr)
+{
+	struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
+
+	inode_init_once(&ei->vfs_inode);
+}
+
+static struct ecryptfs_cache_info {
+	struct kmem_cache **cache;
+	const char *name;
+	size_t size;
+	slab_flags_t flags;
+	void (*ctor)(void *obj);
+} ecryptfs_cache_infos[] = {
+	{
+		.cache = &ecryptfs_auth_tok_list_item_cache,
+		.name = "ecryptfs_auth_tok_list_item",
+		.size = sizeof(struct ecryptfs_auth_tok_list_item),
+	},
+	{
+		.cache = &ecryptfs_file_info_cache,
+		.name = "ecryptfs_file_cache",
+		.size = sizeof(struct ecryptfs_file_info),
+	},
+	{
+		.cache = &ecryptfs_inode_info_cache,
+		.name = "ecryptfs_inode_cache",
+		.size = sizeof(struct ecryptfs_inode_info),
+		.flags = SLAB_ACCOUNT,
+		.ctor = inode_info_init_once,
+	},
+	{
+		.cache = &ecryptfs_sb_info_cache,
+		.name = "ecryptfs_sb_cache",
+		.size = sizeof(struct ecryptfs_sb_info),
+	},
+	{
+		.cache = &ecryptfs_header_cache,
+		.name = "ecryptfs_headers",
+		.size = PAGE_SIZE,
+	},
+	{
+		.cache = &ecryptfs_xattr_cache,
+		.name = "ecryptfs_xattr_cache",
+		.size = PAGE_SIZE,
+	},
+	{
+		.cache = &ecryptfs_key_record_cache,
+		.name = "ecryptfs_key_record_cache",
+		.size = sizeof(struct ecryptfs_key_record),
+	},
+	{
+		.cache = &ecryptfs_key_sig_cache,
+		.name = "ecryptfs_key_sig_cache",
+		.size = sizeof(struct ecryptfs_key_sig),
+	},
+	{
+		.cache = &ecryptfs_global_auth_tok_cache,
+		.name = "ecryptfs_global_auth_tok_cache",
+		.size = sizeof(struct ecryptfs_global_auth_tok),
+	},
+	{
+		.cache = &ecryptfs_key_tfm_cache,
+		.name = "ecryptfs_key_tfm_cache",
+		.size = sizeof(struct ecryptfs_key_tfm),
+	},
+};
+
+static void ecryptfs_free_kmem_caches(void)
+{
+	int i;
+
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+
+	for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
+		struct ecryptfs_cache_info *info;
+
+		info = &ecryptfs_cache_infos[i];
+		kmem_cache_destroy(*(info->cache));
+	}
+}
+
+/**
+ * ecryptfs_init_kmem_caches
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_init_kmem_caches(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
+		struct ecryptfs_cache_info *info;
+
+		info = &ecryptfs_cache_infos[i];
+		*(info->cache) = kmem_cache_create(info->name, info->size, 0,
+				SLAB_HWCACHE_ALIGN | info->flags, info->ctor);
+		if (!*(info->cache)) {
+			ecryptfs_free_kmem_caches();
+			ecryptfs_printk(KERN_WARNING, "%s: "
+					"kmem_cache_create failed\n",
+					info->name);
+			return -ENOMEM;
+		}
+	}
+	return 0;
+}
+
+static struct kobject *ecryptfs_kobj;
+
+static ssize_t version_show(struct kobject *kobj,
+			    struct kobj_attribute *attr, char *buff)
+{
+	return sysfs_emit(buff, "%d\n", ECRYPTFS_VERSIONING_MASK);
+}
+
+static struct kobj_attribute version_attr = __ATTR_RO(version);
+
+static struct attribute *attributes[] = {
+	&version_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group attr_group = {
+	.attrs = attributes,
+};
+
+static int do_sysfs_registration(void)
+{
+	int rc;
+
+	ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
+	if (!ecryptfs_kobj) {
+		printk(KERN_ERR "Unable to create ecryptfs kset\n");
+		rc = -ENOMEM;
+		goto out;
+	}
+	rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
+	if (rc) {
+		printk(KERN_ERR
+		       "Unable to create ecryptfs version attributes\n");
+		kobject_put(ecryptfs_kobj);
+	}
+out:
+	return rc;
+}
+
+static void do_sysfs_unregistration(void)
+{
+	sysfs_remove_group(ecryptfs_kobj, &attr_group);
+	kobject_put(ecryptfs_kobj);
+}
+
+static int __init ecryptfs_init(void)
+{
+	int rc;
+
+	if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_SIZE) {
+		rc = -EINVAL;
+		ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
+				"larger than the host's page size, and so "
+				"eCryptfs cannot run on this system. The "
+				"default eCryptfs extent size is [%u] bytes; "
+				"the page size is [%lu] bytes.\n",
+				ECRYPTFS_DEFAULT_EXTENT_SIZE,
+				(unsigned long)PAGE_SIZE);
+		goto out;
+	}
+	rc = ecryptfs_init_kmem_caches();
+	if (rc) {
+		printk(KERN_ERR
+		       "Failed to allocate one or more kmem_cache objects\n");
+		goto out;
+	}
+	rc = do_sysfs_registration();
+	if (rc) {
+		printk(KERN_ERR "sysfs registration failed\n");
+		goto out_free_kmem_caches;
+	}
+	rc = ecryptfs_init_kthread();
+	if (rc) {
+		printk(KERN_ERR "%s: kthread initialization failed; "
+		       "rc = [%d]\n", __func__, rc);
+		goto out_do_sysfs_unregistration;
+	}
+	rc = ecryptfs_init_messaging();
+	if (rc) {
+		printk(KERN_ERR "Failure occurred while attempting to "
+				"initialize the communications channel to "
+				"ecryptfsd\n");
+		goto out_destroy_kthread;
+	}
+	rc = ecryptfs_init_crypto();
+	if (rc) {
+		printk(KERN_ERR "Failure whilst attempting to init crypto; "
+		       "rc = [%d]\n", rc);
+		goto out_release_messaging;
+	}
+	rc = register_filesystem(&ecryptfs_fs_type);
+	if (rc) {
+		printk(KERN_ERR "Failed to register filesystem\n");
+		goto out_destroy_crypto;
+	}
+	if (ecryptfs_verbosity > 0)
+		printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
+			"will be written to the syslog!\n", ecryptfs_verbosity);
+
+	goto out;
+out_destroy_crypto:
+	ecryptfs_destroy_crypto();
+out_release_messaging:
+	ecryptfs_release_messaging();
+out_destroy_kthread:
+	ecryptfs_destroy_kthread();
+out_do_sysfs_unregistration:
+	do_sysfs_unregistration();
+out_free_kmem_caches:
+	ecryptfs_free_kmem_caches();
+out:
+	return rc;
+}
+
+static void __exit ecryptfs_exit(void)
+{
+	int rc;
+
+	rc = ecryptfs_destroy_crypto();
+	if (rc)
+		printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
+		       "rc = [%d]\n", rc);
+	ecryptfs_release_messaging();
+	ecryptfs_destroy_kthread();
+	do_sysfs_unregistration();
+	unregister_filesystem(&ecryptfs_fs_type);
+	ecryptfs_free_kmem_caches();
+}
+
+MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
+MODULE_DESCRIPTION("eCryptfs");
+
+MODULE_LICENSE("GPL");
+
+module_init(ecryptfs_init)
+module_exit(ecryptfs_exit)

linux-7.2.3/fs/ecryptfs/messaging.c

@@ -0,0 +1,452 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 2004-2008 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
+ *		Tyler Hicks <code@tyhicks.com>
+ */
+#include <linux/overflow.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/user_namespace.h>
+#include <linux/nsproxy.h>
+#include "ecryptfs_kernel.h"
+
+static LIST_HEAD(ecryptfs_msg_ctx_free_list);
+static LIST_HEAD(ecryptfs_msg_ctx_alloc_list);
+static DEFINE_MUTEX(ecryptfs_msg_ctx_lists_mux);
+
+static struct hlist_head *ecryptfs_daemon_hash;
+DEFINE_MUTEX(ecryptfs_daemon_hash_mux);
+static int ecryptfs_hash_bits;
+#define ecryptfs_current_euid_hash(uid) \
+	hash_long((unsigned long)from_kuid(&init_user_ns, current_euid()), ecryptfs_hash_bits)
+
+static u32 ecryptfs_msg_counter;
+static struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr;
+
+/**
+ * ecryptfs_acquire_free_msg_ctx
+ * @msg_ctx: The context that was acquired from the free list
+ *
+ * Acquires a context element from the free list and locks the mutex
+ * on the context.  Sets the msg_ctx task to current.  Returns zero on
+ * success; non-zero on error or upon failure to acquire a free
+ * context element.  Must be called with ecryptfs_msg_ctx_lists_mux
+ * held.
+ */
+static int ecryptfs_acquire_free_msg_ctx(struct ecryptfs_msg_ctx **msg_ctx)
+{
+	struct list_head *p;
+	int rc;
+
+	if (list_empty(&ecryptfs_msg_ctx_free_list)) {
+		printk(KERN_WARNING "%s: The eCryptfs free "
+		       "context list is empty.  It may be helpful to "
+		       "specify the ecryptfs_message_buf_len "
+		       "parameter to be greater than the current "
+		       "value of [%d]\n", __func__, ecryptfs_message_buf_len);
+		rc = -ENOMEM;
+		goto out;
+	}
+	list_for_each(p, &ecryptfs_msg_ctx_free_list) {
+		*msg_ctx = list_entry(p, struct ecryptfs_msg_ctx, node);
+		if (mutex_trylock(&(*msg_ctx)->mux)) {
+			(*msg_ctx)->task = current;
+			rc = 0;
+			goto out;
+		}
+	}
+	rc = -ENOMEM;
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_msg_ctx_free_to_alloc
+ * @msg_ctx: The context to move from the free list to the alloc list
+ *
+ * Must be called with ecryptfs_msg_ctx_lists_mux held.
+ */
+static void ecryptfs_msg_ctx_free_to_alloc(struct ecryptfs_msg_ctx *msg_ctx)
+{
+	list_move(&msg_ctx->node, &ecryptfs_msg_ctx_alloc_list);
+	msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_PENDING;
+	msg_ctx->counter = ++ecryptfs_msg_counter;
+}
+
+/**
+ * ecryptfs_msg_ctx_alloc_to_free
+ * @msg_ctx: The context to move from the alloc list to the free list
+ *
+ * Must be called with ecryptfs_msg_ctx_lists_mux held.
+ */
+void ecryptfs_msg_ctx_alloc_to_free(struct ecryptfs_msg_ctx *msg_ctx)
+{
+	list_move(&(msg_ctx->node), &ecryptfs_msg_ctx_free_list);
+	kfree(msg_ctx->msg);
+	msg_ctx->msg = NULL;
+	msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_FREE;
+}
+
+/**
+ * ecryptfs_find_daemon_by_euid
+ * @daemon: If return value is zero, points to the desired daemon pointer
+ *
+ * Must be called with ecryptfs_daemon_hash_mux held.
+ *
+ * Search the hash list for the current effective user id.
+ *
+ * Returns zero if the user id exists in the list; non-zero otherwise.
+ */
+int ecryptfs_find_daemon_by_euid(struct ecryptfs_daemon **daemon)
+{
+	int rc;
+
+	hlist_for_each_entry(*daemon,
+			    &ecryptfs_daemon_hash[ecryptfs_current_euid_hash()],
+			    euid_chain) {
+		if (uid_eq((*daemon)->file->f_cred->euid, current_euid())) {
+			rc = 0;
+			goto out;
+		}
+	}
+	rc = -EINVAL;
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_spawn_daemon - Create and initialize a new daemon struct
+ * @daemon: Pointer to set to newly allocated daemon struct
+ * @file: File used when opening /dev/ecryptfs
+ *
+ * Must be called ceremoniously while in possession of
+ * ecryptfs_sacred_daemon_hash_mux
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int
+ecryptfs_spawn_daemon(struct ecryptfs_daemon **daemon, struct file *file)
+{
+	int rc = 0;
+
+	(*daemon) = kzalloc_obj(**daemon);
+	if (!(*daemon)) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	(*daemon)->file = file;
+	mutex_init(&(*daemon)->mux);
+	INIT_LIST_HEAD(&(*daemon)->msg_ctx_out_queue);
+	init_waitqueue_head(&(*daemon)->wait);
+	(*daemon)->num_queued_msg_ctx = 0;
+	hlist_add_head(&(*daemon)->euid_chain,
+		       &ecryptfs_daemon_hash[ecryptfs_current_euid_hash()]);
+out:
+	return rc;
+}
+
+/*
+ * ecryptfs_exorcise_daemon - Destroy the daemon struct
+ *
+ * Must be called ceremoniously while in possession of
+ * ecryptfs_daemon_hash_mux and the daemon's own mux.
+ */
+int ecryptfs_exorcise_daemon(struct ecryptfs_daemon *daemon)
+{
+	struct ecryptfs_msg_ctx *msg_ctx, *msg_ctx_tmp;
+	int rc = 0;
+
+	mutex_lock(&daemon->mux);
+	if ((daemon->flags & ECRYPTFS_DAEMON_IN_READ)
+	    || (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)) {
+		rc = -EBUSY;
+		mutex_unlock(&daemon->mux);
+		goto out;
+	}
+	list_for_each_entry_safe(msg_ctx, msg_ctx_tmp,
+				 &daemon->msg_ctx_out_queue, daemon_out_list) {
+		list_del(&msg_ctx->daemon_out_list);
+		daemon->num_queued_msg_ctx--;
+		printk(KERN_WARNING "%s: Warning: dropping message that is in "
+		       "the out queue of a dying daemon\n", __func__);
+		ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
+	}
+	hlist_del(&daemon->euid_chain);
+	mutex_unlock(&daemon->mux);
+	kfree_sensitive(daemon);
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_process_response
+ * @daemon: eCryptfs daemon object
+ * @msg: The ecryptfs message received; the caller should sanity check
+ *       msg->data_len and free the memory
+ * @seq: The sequence number of the message; must match the sequence
+ *       number for the existing message context waiting for this
+ *       response
+ *
+ * Processes a response message after sending an operation request to
+ * userspace. Some other process is awaiting this response. Before
+ * sending out its first communications, the other process allocated a
+ * msg_ctx from the ecryptfs_msg_ctx_arr at a particular index. The
+ * response message contains this index so that we can copy over the
+ * response message into the msg_ctx that the process holds a
+ * reference to. The other process is going to wake up, check to see
+ * that msg_ctx->state == ECRYPTFS_MSG_CTX_STATE_DONE, and then
+ * proceed to read off and process the response message. Returns zero
+ * upon delivery to desired context element; non-zero upon delivery
+ * failure or error.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_process_response(struct ecryptfs_daemon *daemon,
+			      struct ecryptfs_message *msg, u32 seq)
+{
+	struct ecryptfs_msg_ctx *msg_ctx;
+	size_t msg_size;
+	int rc;
+
+	if (msg->index >= ecryptfs_message_buf_len) {
+		rc = -EINVAL;
+		printk(KERN_ERR "%s: Attempt to reference "
+		       "context buffer at index [%d]; maximum "
+		       "allowable is [%d]\n", __func__, msg->index,
+		       (ecryptfs_message_buf_len - 1));
+		goto out;
+	}
+	msg_ctx = &ecryptfs_msg_ctx_arr[msg->index];
+	mutex_lock(&msg_ctx->mux);
+	if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_PENDING) {
+		rc = -EINVAL;
+		printk(KERN_WARNING "%s: Desired context element is not "
+		       "pending a response\n", __func__);
+		goto unlock;
+	} else if (msg_ctx->counter != seq) {
+		rc = -EINVAL;
+		printk(KERN_WARNING "%s: Invalid message sequence; "
+		       "expected [%d]; received [%d]\n", __func__,
+		       msg_ctx->counter, seq);
+		goto unlock;
+	}
+	msg_size = struct_size(msg, data, msg->data_len);
+	msg_ctx->msg = kmemdup(msg, msg_size, GFP_KERNEL);
+	if (!msg_ctx->msg) {
+		rc = -ENOMEM;
+		goto unlock;
+	}
+	msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_DONE;
+	wake_up_process(msg_ctx->task);
+	rc = 0;
+unlock:
+	mutex_unlock(&msg_ctx->mux);
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_send_message_locked
+ * @data: The data to send
+ * @data_len: The length of data
+ * @msg_type: Type of message
+ * @msg_ctx: The message context allocated for the send
+ *
+ * Must be called with ecryptfs_daemon_hash_mux held.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int
+ecryptfs_send_message_locked(char *data, int data_len, u8 msg_type,
+			     struct ecryptfs_msg_ctx **msg_ctx)
+{
+	struct ecryptfs_daemon *daemon;
+	int rc;
+
+	rc = ecryptfs_find_daemon_by_euid(&daemon);
+	if (rc) {
+		rc = -ENOTCONN;
+		goto out;
+	}
+	mutex_lock(&ecryptfs_msg_ctx_lists_mux);
+	rc = ecryptfs_acquire_free_msg_ctx(msg_ctx);
+	if (rc) {
+		mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+		printk(KERN_WARNING "%s: Could not claim a free "
+		       "context element\n", __func__);
+		goto out;
+	}
+	ecryptfs_msg_ctx_free_to_alloc(*msg_ctx);
+	mutex_unlock(&(*msg_ctx)->mux);
+	mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+	rc = ecryptfs_send_miscdev(data, data_len, *msg_ctx, msg_type, 0,
+				   daemon);
+	if (rc)
+		printk(KERN_ERR "%s: Error attempting to send message to "
+		       "userspace daemon; rc = [%d]\n", __func__, rc);
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_send_message
+ * @data: The data to send
+ * @data_len: The length of data
+ * @msg_ctx: The message context allocated for the send
+ *
+ * Grabs ecryptfs_daemon_hash_mux.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_send_message(char *data, int data_len,
+			  struct ecryptfs_msg_ctx **msg_ctx)
+{
+	int rc;
+
+	mutex_lock(&ecryptfs_daemon_hash_mux);
+	rc = ecryptfs_send_message_locked(data, data_len, ECRYPTFS_MSG_REQUEST,
+					  msg_ctx);
+	mutex_unlock(&ecryptfs_daemon_hash_mux);
+	return rc;
+}
+
+/**
+ * ecryptfs_wait_for_response
+ * @msg_ctx: The context that was assigned when sending a message
+ * @msg: The incoming message from userspace; not set if rc != 0
+ *
+ * Sleeps until awaken by ecryptfs_receive_message or until the amount
+ * of time exceeds ecryptfs_message_wait_timeout.  If zero is
+ * returned, msg will point to a valid message from userspace; a
+ * non-zero value is returned upon failure to receive a message or an
+ * error occurs. Callee must free @msg on success.
+ */
+int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx,
+			       struct ecryptfs_message **msg)
+{
+	signed long timeout = ecryptfs_message_wait_timeout * HZ;
+	int rc = 0;
+
+sleep:
+	timeout = schedule_timeout_interruptible(timeout);
+	mutex_lock(&ecryptfs_msg_ctx_lists_mux);
+	mutex_lock(&msg_ctx->mux);
+	if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_DONE) {
+		if (timeout) {
+			mutex_unlock(&msg_ctx->mux);
+			mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+			goto sleep;
+		}
+		rc = -ENOMSG;
+	} else {
+		*msg = msg_ctx->msg;
+		msg_ctx->msg = NULL;
+	}
+	ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
+	mutex_unlock(&msg_ctx->mux);
+	mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+	return rc;
+}
+
+int __init ecryptfs_init_messaging(void)
+{
+	int i;
+	int rc = 0;
+
+	if (ecryptfs_number_of_users > ECRYPTFS_MAX_NUM_USERS) {
+		ecryptfs_number_of_users = ECRYPTFS_MAX_NUM_USERS;
+		printk(KERN_WARNING "%s: Specified number of users is "
+		       "too large, defaulting to [%d] users\n", __func__,
+		       ecryptfs_number_of_users);
+	}
+	mutex_lock(&ecryptfs_daemon_hash_mux);
+	ecryptfs_hash_bits = 1;
+	while (ecryptfs_number_of_users >> ecryptfs_hash_bits)
+		ecryptfs_hash_bits++;
+	ecryptfs_daemon_hash = kmalloc((sizeof(struct hlist_head)
+					* (1 << ecryptfs_hash_bits)),
+				       GFP_KERNEL);
+	if (!ecryptfs_daemon_hash) {
+		rc = -ENOMEM;
+		mutex_unlock(&ecryptfs_daemon_hash_mux);
+		goto out;
+	}
+	for (i = 0; i < (1 << ecryptfs_hash_bits); i++)
+		INIT_HLIST_HEAD(&ecryptfs_daemon_hash[i]);
+	mutex_unlock(&ecryptfs_daemon_hash_mux);
+	ecryptfs_msg_ctx_arr = kmalloc((sizeof(struct ecryptfs_msg_ctx)
+					* ecryptfs_message_buf_len),
+				       GFP_KERNEL);
+	if (!ecryptfs_msg_ctx_arr) {
+		kfree(ecryptfs_daemon_hash);
+		rc = -ENOMEM;
+		goto out;
+	}
+	mutex_lock(&ecryptfs_msg_ctx_lists_mux);
+	ecryptfs_msg_counter = 0;
+	for (i = 0; i < ecryptfs_message_buf_len; i++) {
+		INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].node);
+		INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].daemon_out_list);
+		mutex_init(&ecryptfs_msg_ctx_arr[i].mux);
+		mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
+		ecryptfs_msg_ctx_arr[i].index = i;
+		ecryptfs_msg_ctx_arr[i].state = ECRYPTFS_MSG_CTX_STATE_FREE;
+		ecryptfs_msg_ctx_arr[i].counter = 0;
+		ecryptfs_msg_ctx_arr[i].task = NULL;
+		ecryptfs_msg_ctx_arr[i].msg = NULL;
+		list_add_tail(&ecryptfs_msg_ctx_arr[i].node,
+			      &ecryptfs_msg_ctx_free_list);
+		mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
+	}
+	mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+	rc = ecryptfs_init_ecryptfs_miscdev();
+	if (rc)
+		ecryptfs_release_messaging();
+out:
+	return rc;
+}
+
+void ecryptfs_release_messaging(void)
+{
+	if (ecryptfs_msg_ctx_arr) {
+		int i;
+
+		mutex_lock(&ecryptfs_msg_ctx_lists_mux);
+		for (i = 0; i < ecryptfs_message_buf_len; i++) {
+			mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
+			kfree(ecryptfs_msg_ctx_arr[i].msg);
+			mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
+		}
+		kfree(ecryptfs_msg_ctx_arr);
+		mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+	}
+	if (ecryptfs_daemon_hash) {
+		struct ecryptfs_daemon *daemon;
+		struct hlist_node *n;
+		int i;
+
+		mutex_lock(&ecryptfs_daemon_hash_mux);
+		for (i = 0; i < (1 << ecryptfs_hash_bits); i++) {
+			int rc;
+
+			hlist_for_each_entry_safe(daemon, n,
+						  &ecryptfs_daemon_hash[i],
+						  euid_chain) {
+				rc = ecryptfs_exorcise_daemon(daemon);
+				if (rc)
+					printk(KERN_ERR "%s: Error whilst "
+					       "attempting to destroy daemon; "
+					       "rc = [%d]. Dazed and confused, "
+					       "but trying to continue.\n",
+					       __func__, rc);
+			}
+		}
+		kfree(ecryptfs_daemon_hash);
+		mutex_unlock(&ecryptfs_daemon_hash_mux);
+	}
+	ecryptfs_destroy_ecryptfs_miscdev();
+	return;
+}

linux-7.2.3/fs/ecryptfs/miscdev.c

@@ -0,0 +1,498 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 2008 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
+ */
+
+#include <linux/fs.h>
+#include <linux/hash.h>
+#include <linux/random.h>
+#include <linux/miscdevice.h>
+#include <linux/overflow.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/module.h>
+#include "ecryptfs_kernel.h"
+
+static atomic_t ecryptfs_num_miscdev_opens;
+
+/**
+ * ecryptfs_miscdev_poll
+ * @file: dev file
+ * @pt: dev poll table (ignored)
+ *
+ * Returns the poll mask
+ */
+static __poll_t
+ecryptfs_miscdev_poll(struct file *file, poll_table *pt)
+{
+	struct ecryptfs_daemon *daemon = file->private_data;
+	__poll_t mask = 0;
+
+	mutex_lock(&daemon->mux);
+	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
+		printk(KERN_WARNING "%s: Attempt to poll on zombified "
+		       "daemon\n", __func__);
+		goto out_unlock_daemon;
+	}
+	if (daemon->flags & ECRYPTFS_DAEMON_IN_READ)
+		goto out_unlock_daemon;
+	if (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)
+		goto out_unlock_daemon;
+	daemon->flags |= ECRYPTFS_DAEMON_IN_POLL;
+	mutex_unlock(&daemon->mux);
+	poll_wait(file, &daemon->wait, pt);
+	mutex_lock(&daemon->mux);
+	if (!list_empty(&daemon->msg_ctx_out_queue))
+		mask |= EPOLLIN | EPOLLRDNORM;
+out_unlock_daemon:
+	daemon->flags &= ~ECRYPTFS_DAEMON_IN_POLL;
+	mutex_unlock(&daemon->mux);
+	return mask;
+}
+
+/**
+ * ecryptfs_miscdev_open
+ * @inode: inode of miscdev handle (ignored)
+ * @file: file for miscdev handle
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int
+ecryptfs_miscdev_open(struct inode *inode, struct file *file)
+{
+	struct ecryptfs_daemon *daemon = NULL;
+	int rc;
+
+	mutex_lock(&ecryptfs_daemon_hash_mux);
+	rc = ecryptfs_find_daemon_by_euid(&daemon);
+	if (!rc) {
+		rc = -EINVAL;
+		goto out_unlock_daemon_list;
+	}
+	rc = ecryptfs_spawn_daemon(&daemon, file);
+	if (rc) {
+		printk(KERN_ERR "%s: Error attempting to spawn daemon; "
+		       "rc = [%d]\n", __func__, rc);
+		goto out_unlock_daemon_list;
+	}
+	mutex_lock(&daemon->mux);
+	if (daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) {
+		rc = -EBUSY;
+		goto out_unlock_daemon;
+	}
+	daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN;
+	file->private_data = daemon;
+	atomic_inc(&ecryptfs_num_miscdev_opens);
+out_unlock_daemon:
+	mutex_unlock(&daemon->mux);
+out_unlock_daemon_list:
+	mutex_unlock(&ecryptfs_daemon_hash_mux);
+	return rc;
+}
+
+/**
+ * ecryptfs_miscdev_release
+ * @inode: inode of fs/ecryptfs/euid handle (ignored)
+ * @file: file for fs/ecryptfs/euid handle
+ *
+ * This keeps the daemon registered until the daemon sends another
+ * ioctl to fs/ecryptfs/ctl or until the kernel module unregisters.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int
+ecryptfs_miscdev_release(struct inode *inode, struct file *file)
+{
+	struct ecryptfs_daemon *daemon = file->private_data;
+	int rc;
+
+	mutex_lock(&daemon->mux);
+	BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN));
+	daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN;
+	atomic_dec(&ecryptfs_num_miscdev_opens);
+	mutex_unlock(&daemon->mux);
+
+	mutex_lock(&ecryptfs_daemon_hash_mux);
+	rc = ecryptfs_exorcise_daemon(daemon);
+	mutex_unlock(&ecryptfs_daemon_hash_mux);
+	if (rc) {
+		printk(KERN_CRIT "%s: Fatal error whilst attempting to "
+		       "shut down daemon; rc = [%d]. Please report this "
+		       "bug.\n", __func__, rc);
+		BUG();
+	}
+	return rc;
+}
+
+/**
+ * ecryptfs_send_miscdev
+ * @data: Data to send to daemon; may be NULL
+ * @data_size: Amount of data to send to daemon
+ * @msg_ctx: Message context, which is used to handle the reply. If
+ *           this is NULL, then we do not expect a reply.
+ * @msg_type: Type of message
+ * @msg_flags: Flags for message
+ * @daemon: eCryptfs daemon object
+ *
+ * Add msg_ctx to queue and then, if it exists, notify the blocked
+ * miscdevess about the data being available. Must be called with
+ * ecryptfs_daemon_hash_mux held.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_send_miscdev(char *data, size_t data_size,
+			  struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type,
+			  u16 msg_flags, struct ecryptfs_daemon *daemon)
+{
+	struct ecryptfs_message *msg;
+	size_t msg_size;
+
+	msg_size = struct_size(msg, data, data_size);
+	msg = kmalloc(msg_size, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	mutex_lock(&msg_ctx->mux);
+	msg_ctx->msg = msg;
+	msg_ctx->msg->index = msg_ctx->index;
+	msg_ctx->msg->data_len = data_size;
+	msg_ctx->type = msg_type;
+	memcpy(msg_ctx->msg->data, data, data_size);
+	msg_ctx->msg_size = msg_size;
+	list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue);
+	mutex_unlock(&msg_ctx->mux);
+
+	mutex_lock(&daemon->mux);
+	daemon->num_queued_msg_ctx++;
+	wake_up_interruptible(&daemon->wait);
+	mutex_unlock(&daemon->mux);
+
+	return 0;
+}
+
+/*
+ * miscdevfs packet format:
+ *  Octet 0: Type
+ *  Octets 1-4: network byte order msg_ctx->counter
+ *  Octets 5-N0: Size of struct ecryptfs_message to follow
+ *  Octets N0-N1: struct ecryptfs_message (including data)
+ *
+ *  Octets 5-N1 not written if the packet type does not include a message
+ */
+#define PKT_TYPE_SIZE		1
+#define PKT_CTR_SIZE		4
+#define MIN_NON_MSG_PKT_SIZE	(PKT_TYPE_SIZE + PKT_CTR_SIZE)
+#define MIN_MSG_PKT_SIZE	(PKT_TYPE_SIZE + PKT_CTR_SIZE \
+				 + ECRYPTFS_MIN_PKT_LEN_SIZE)
+/* 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES comes from tag 65 packet format */
+#define MAX_MSG_PKT_SIZE	(PKT_TYPE_SIZE + PKT_CTR_SIZE \
+				 + ECRYPTFS_MAX_PKT_LEN_SIZE \
+				 + sizeof(struct ecryptfs_message) \
+				 + 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES)
+#define PKT_TYPE_OFFSET		0
+#define PKT_CTR_OFFSET		PKT_TYPE_SIZE
+#define PKT_LEN_OFFSET		(PKT_TYPE_SIZE + PKT_CTR_SIZE)
+
+/**
+ * ecryptfs_miscdev_read - format and send message from queue
+ * @file: miscdevfs handle
+ * @buf: User buffer into which to copy the next message on the daemon queue
+ * @count: Amount of space available in @buf
+ * @ppos: Offset in file (ignored)
+ *
+ * Pulls the most recent message from the daemon queue, formats it for
+ * being sent via a miscdevfs handle, and copies it into @buf
+ *
+ * Returns the number of bytes copied into the user buffer
+ */
+static ssize_t
+ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count,
+		      loff_t *ppos)
+{
+	struct ecryptfs_daemon *daemon = file->private_data;
+	struct ecryptfs_msg_ctx *msg_ctx;
+	size_t packet_length_size;
+	char packet_length[ECRYPTFS_MAX_PKT_LEN_SIZE];
+	size_t i;
+	size_t total_length;
+	int rc;
+
+	mutex_lock(&daemon->mux);
+	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
+		rc = 0;
+		printk(KERN_WARNING "%s: Attempt to read from zombified "
+		       "daemon\n", __func__);
+		goto out_unlock_daemon;
+	}
+	if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) {
+		rc = 0;
+		goto out_unlock_daemon;
+	}
+	/* This daemon will not go away so long as this flag is set */
+	daemon->flags |= ECRYPTFS_DAEMON_IN_READ;
+check_list:
+	if (list_empty(&daemon->msg_ctx_out_queue)) {
+		mutex_unlock(&daemon->mux);
+		rc = wait_event_interruptible(
+			daemon->wait, !list_empty(&daemon->msg_ctx_out_queue));
+		mutex_lock(&daemon->mux);
+		if (rc < 0) {
+			rc = 0;
+			goto out_unlock_daemon;
+		}
+	}
+	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
+		rc = 0;
+		goto out_unlock_daemon;
+	}
+	if (list_empty(&daemon->msg_ctx_out_queue)) {
+		/* Something else jumped in since the
+		 * wait_event_interruptable() and removed the
+		 * message from the queue; try again */
+		goto check_list;
+	}
+	msg_ctx = list_first_entry(&daemon->msg_ctx_out_queue,
+				   struct ecryptfs_msg_ctx, daemon_out_list);
+	BUG_ON(!msg_ctx);
+	mutex_lock(&msg_ctx->mux);
+	if (msg_ctx->msg) {
+		rc = ecryptfs_write_packet_length(packet_length,
+						  msg_ctx->msg_size,
+						  &packet_length_size);
+		if (rc) {
+			rc = 0;
+			printk(KERN_WARNING "%s: Error writing packet length; "
+			       "rc = [%d]\n", __func__, rc);
+			goto out_unlock_msg_ctx;
+		}
+	} else {
+		packet_length_size = 0;
+		msg_ctx->msg_size = 0;
+	}
+	total_length = (PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_length_size
+			+ msg_ctx->msg_size);
+	if (count < total_length) {
+		rc = 0;
+		printk(KERN_WARNING "%s: Only given user buffer of "
+		       "size [%zd], but we need [%zd] to read the "
+		       "pending message\n", __func__, count, total_length);
+		goto out_unlock_msg_ctx;
+	}
+	rc = -EFAULT;
+	if (put_user(msg_ctx->type, buf))
+		goto out_unlock_msg_ctx;
+	if (put_user(cpu_to_be32(msg_ctx->counter),
+		     (__be32 __user *)(&buf[PKT_CTR_OFFSET])))
+		goto out_unlock_msg_ctx;
+	i = PKT_TYPE_SIZE + PKT_CTR_SIZE;
+	if (msg_ctx->msg) {
+		if (copy_to_user(&buf[i], packet_length, packet_length_size))
+			goto out_unlock_msg_ctx;
+		i += packet_length_size;
+		if (copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size))
+			goto out_unlock_msg_ctx;
+		i += msg_ctx->msg_size;
+	}
+	rc = i;
+	list_del(&msg_ctx->daemon_out_list);
+	kfree(msg_ctx->msg);
+	msg_ctx->msg = NULL;
+	/* We do not expect a reply from the userspace daemon for any
+	 * message type other than ECRYPTFS_MSG_REQUEST */
+	if (msg_ctx->type != ECRYPTFS_MSG_REQUEST)
+		ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
+out_unlock_msg_ctx:
+	mutex_unlock(&msg_ctx->mux);
+out_unlock_daemon:
+	daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ;
+	mutex_unlock(&daemon->mux);
+	return rc;
+}
+
+/**
+ * ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon
+ * @daemon: eCryptfs daemon object
+ * @data: Bytes comprising struct ecryptfs_message
+ * @data_size: sizeof(struct ecryptfs_message) + data len
+ * @seq: Sequence number for miscdev response packet
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_miscdev_response(struct ecryptfs_daemon *daemon, char *data,
+				     size_t data_size, u32 seq)
+{
+	struct ecryptfs_message *msg = (struct ecryptfs_message *)data;
+	int rc;
+
+	if ((sizeof(*msg) + msg->data_len) != data_size) {
+		printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = "
+		       "[%zd]; data_size = [%zd]. Invalid packet.\n", __func__,
+		       (sizeof(*msg) + msg->data_len), data_size);
+		rc = -EINVAL;
+		goto out;
+	}
+	rc = ecryptfs_process_response(daemon, msg, seq);
+	if (rc)
+		printk(KERN_ERR
+		       "Error processing response message; rc = [%d]\n", rc);
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_miscdev_write - handle write to daemon miscdev handle
+ * @file: File for misc dev handle
+ * @buf: Buffer containing user data
+ * @count: Amount of data in @buf
+ * @ppos: Pointer to offset in file (ignored)
+ *
+ * Returns the number of bytes read from @buf
+ */
+static ssize_t
+ecryptfs_miscdev_write(struct file *file, const char __user *buf,
+		       size_t count, loff_t *ppos)
+{
+	__be32 counter_nbo;
+	u32 seq;
+	size_t packet_size, packet_size_length;
+	char *data;
+	unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE];
+	ssize_t rc;
+
+	if (count == 0) {
+		return 0;
+	} else if (count == MIN_NON_MSG_PKT_SIZE) {
+		/* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */
+		goto memdup;
+	} else if (count < MIN_MSG_PKT_SIZE || count > MAX_MSG_PKT_SIZE) {
+		printk(KERN_WARNING "%s: Acceptable packet size range is "
+		       "[%d-%zu], but amount of data written is [%zu].\n",
+		       __func__, MIN_MSG_PKT_SIZE, MAX_MSG_PKT_SIZE, count);
+		return -EINVAL;
+	}
+
+	if (copy_from_user(packet_size_peek, &buf[PKT_LEN_OFFSET],
+			   sizeof(packet_size_peek))) {
+		printk(KERN_WARNING "%s: Error while inspecting packet size\n",
+		       __func__);
+		return -EFAULT;
+	}
+
+	rc = ecryptfs_parse_packet_length(packet_size_peek, &packet_size,
+					  &packet_size_length);
+	if (rc) {
+		printk(KERN_WARNING "%s: Error parsing packet length; "
+		       "rc = [%zd]\n", __func__, rc);
+		return rc;
+	}
+
+	if ((PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_size_length + packet_size)
+	    != count) {
+		printk(KERN_WARNING "%s: Invalid packet size [%zu]\n", __func__,
+		       packet_size);
+		return -EINVAL;
+	}
+
+memdup:
+	data = memdup_user(buf, count);
+	if (IS_ERR(data)) {
+		printk(KERN_ERR "%s: memdup_user returned error [%ld]\n",
+		       __func__, PTR_ERR(data));
+		return PTR_ERR(data);
+	}
+	switch (data[PKT_TYPE_OFFSET]) {
+	case ECRYPTFS_MSG_RESPONSE:
+		if (count < (MIN_MSG_PKT_SIZE
+			     + sizeof(struct ecryptfs_message))) {
+			printk(KERN_WARNING "%s: Minimum acceptable packet "
+			       "size is [%zd], but amount of data written is "
+			       "only [%zd]. Discarding response packet.\n",
+			       __func__,
+			       (MIN_MSG_PKT_SIZE
+				+ sizeof(struct ecryptfs_message)), count);
+			rc = -EINVAL;
+			goto out_free;
+		}
+		memcpy(&counter_nbo, &data[PKT_CTR_OFFSET], PKT_CTR_SIZE);
+		seq = be32_to_cpu(counter_nbo);
+		rc = ecryptfs_miscdev_response(file->private_data,
+				&data[PKT_LEN_OFFSET + packet_size_length],
+				packet_size, seq);
+		if (rc) {
+			printk(KERN_WARNING "%s: Failed to deliver miscdev "
+			       "response to requesting operation; rc = [%zd]\n",
+			       __func__, rc);
+			goto out_free;
+		}
+		break;
+	case ECRYPTFS_MSG_HELO:
+	case ECRYPTFS_MSG_QUIT:
+		break;
+	default:
+		ecryptfs_printk(KERN_WARNING, "Dropping miscdev "
+				"message of unrecognized type [%d]\n",
+				data[0]);
+		rc = -EINVAL;
+		goto out_free;
+	}
+	rc = count;
+out_free:
+	kfree(data);
+	return rc;
+}
+
+
+static const struct file_operations ecryptfs_miscdev_fops = {
+	.owner   = THIS_MODULE,
+	.open    = ecryptfs_miscdev_open,
+	.poll    = ecryptfs_miscdev_poll,
+	.read    = ecryptfs_miscdev_read,
+	.write   = ecryptfs_miscdev_write,
+	.release = ecryptfs_miscdev_release,
+	.llseek  = noop_llseek,
+};
+
+static struct miscdevice ecryptfs_miscdev = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name  = "ecryptfs",
+	.fops  = &ecryptfs_miscdev_fops
+};
+
+/**
+ * ecryptfs_init_ecryptfs_miscdev
+ *
+ * Messages sent to the userspace daemon from the kernel are placed on
+ * a queue associated with the daemon. The next read against the
+ * miscdev handle by that daemon will return the oldest message placed
+ * on the message queue for the daemon.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int __init ecryptfs_init_ecryptfs_miscdev(void)
+{
+	int rc;
+
+	atomic_set(&ecryptfs_num_miscdev_opens, 0);
+	rc = misc_register(&ecryptfs_miscdev);
+	if (rc)
+		printk(KERN_ERR "%s: Failed to register miscellaneous device "
+		       "for communications with userspace daemons; rc = [%d]\n",
+		       __func__, rc);
+	return rc;
+}
+
+/**
+ * ecryptfs_destroy_ecryptfs_miscdev
+ *
+ * All of the daemons must be exorcised prior to calling this
+ * function.
+ */
+void ecryptfs_destroy_ecryptfs_miscdev(void)
+{
+	BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0);
+	misc_deregister(&ecryptfs_miscdev);
+}

linux-7.2.3/fs/ecryptfs/mmap.c

@@ -0,0 +1,534 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ * This is where eCryptfs coordinates the symmetric encryption and
+ * decryption of the file data as it passes between the lower
+ * encrypted file and the upper decrypted file.
+ *
+ * Copyright (C) 1997-2003 Erez Zadok
+ * Copyright (C) 2001-2003 Stony Brook University
+ * Copyright (C) 2004-2007 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ */
+
+#include <linux/pagemap.h>
+#include <linux/writeback.h>
+#include <linux/page-flags.h>
+#include <linux/mount.h>
+#include <linux/file.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+#include <linux/xattr.h>
+#include <linux/unaligned.h>
+#include "ecryptfs_kernel.h"
+
+/*
+ * This is where we encrypt the data and pass the encrypted data to
+ * the lower filesystem.  In OpenPGP-compatible mode, we operate on
+ * entire underlying packets.
+ */
+static int ecryptfs_writepages(struct address_space *mapping,
+		struct writeback_control *wbc)
+{
+	struct folio *folio = NULL;
+	int error;
+
+	while ((folio = writeback_iter(mapping, wbc, folio, &error))) {
+		error = ecryptfs_encrypt_page(folio);
+		if (error) {
+			ecryptfs_printk(KERN_WARNING,
+				"Error encrypting folio (index [0x%.16lx])\n",
+				folio->index);
+			folio_clear_uptodate(folio);
+			mapping_set_error(mapping, error);
+		}
+		folio_unlock(folio);
+	}
+
+	return error;
+}
+
+static void strip_xattr_flag(char *page_virt,
+			     struct ecryptfs_crypt_stat *crypt_stat)
+{
+	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
+		size_t written;
+
+		crypt_stat->flags &= ~ECRYPTFS_METADATA_IN_XATTR;
+		ecryptfs_write_crypt_stat_flags(page_virt, crypt_stat,
+						&written);
+		crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
+	}
+}
+
+/*
+ *   Header Extent:
+ *     Octets 0-7:        Unencrypted file size (big-endian)
+ *     Octets 8-15:       eCryptfs special marker
+ *     Octets 16-19:      Flags
+ *      Octet 16:         File format version number (between 0 and 255)
+ *      Octets 17-18:     Reserved
+ *      Octet 19:         Bit 1 (lsb): Reserved
+ *                        Bit 2: Encrypted?
+ *                        Bits 3-8: Reserved
+ *     Octets 20-23:      Header extent size (big-endian)
+ *     Octets 24-25:      Number of header extents at front of file
+ *                        (big-endian)
+ *     Octet  26:         Begin RFC 2440 authentication token packet set
+ */
+
+/**
+ * ecryptfs_copy_up_encrypted_with_header
+ * @folio: Sort of a ``virtual'' representation of the encrypted lower
+ *        file. The actual lower file does not have the metadata in
+ *        the header. This is locked.
+ * @crypt_stat: The eCryptfs inode's cryptographic context
+ *
+ * The ``view'' is the version of the file that userspace winds up
+ * seeing, with the header information inserted.
+ */
+static int
+ecryptfs_copy_up_encrypted_with_header(struct folio *folio,
+				       struct ecryptfs_crypt_stat *crypt_stat)
+{
+	loff_t extent_num_in_page = 0;
+	loff_t num_extents_per_page = (PAGE_SIZE
+				       / crypt_stat->extent_size);
+	int rc = 0;
+
+	while (extent_num_in_page < num_extents_per_page) {
+		loff_t view_extent_num = ((loff_t)folio->index
+					   * num_extents_per_page)
+					  + extent_num_in_page;
+		size_t num_header_extents_at_front =
+			(crypt_stat->metadata_size / crypt_stat->extent_size);
+
+		if (view_extent_num < num_header_extents_at_front) {
+			/* This is a header extent */
+			char *page_virt;
+
+			page_virt = kmap_local_folio(folio, 0);
+			memset(page_virt, 0, PAGE_SIZE);
+			/* TODO: Support more than one header extent */
+			if (view_extent_num == 0) {
+				size_t written;
+
+				rc = ecryptfs_read_xattr_region(
+					page_virt, folio->mapping->host);
+				strip_xattr_flag(page_virt + 16, crypt_stat);
+				ecryptfs_write_header_metadata(page_virt + 20,
+							       crypt_stat,
+							       &written);
+			}
+			kunmap_local(page_virt);
+			flush_dcache_folio(folio);
+			if (rc) {
+				printk(KERN_ERR "%s: Error reading xattr "
+				       "region; rc = [%d]\n", __func__, rc);
+				goto out;
+			}
+		} else {
+			/* This is an encrypted data extent */
+			loff_t lower_offset =
+				((view_extent_num * crypt_stat->extent_size)
+				 - crypt_stat->metadata_size);
+
+			rc = ecryptfs_read_lower_page_segment(
+				folio, (lower_offset >> PAGE_SHIFT),
+				(lower_offset & ~PAGE_MASK),
+				crypt_stat->extent_size, folio->mapping->host);
+			if (rc) {
+				printk(KERN_ERR "%s: Error attempting to read "
+				       "extent at offset [%lld] in the lower "
+				       "file; rc = [%d]\n", __func__,
+				       lower_offset, rc);
+				goto out;
+			}
+		}
+		extent_num_in_page++;
+	}
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_read_folio
+ * @file: An eCryptfs file
+ * @folio: Folio from eCryptfs inode mapping into which to stick the read data
+ *
+ * Read in a folio, decrypting if necessary.
+ *
+ * Returns zero on success; non-zero on error.
+ */
+static int ecryptfs_read_folio(struct file *file, struct folio *folio)
+{
+	struct inode *inode = folio->mapping->host;
+	struct ecryptfs_crypt_stat *crypt_stat =
+		&ecryptfs_inode_to_private(inode)->crypt_stat;
+	int err = 0;
+
+	if (!crypt_stat || !(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
+		err = ecryptfs_read_lower_page_segment(folio, folio->index, 0,
+				folio_size(folio), inode);
+	} else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
+		if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
+			err = ecryptfs_copy_up_encrypted_with_header(folio,
+					crypt_stat);
+			if (err) {
+				printk(KERN_ERR "%s: Error attempting to copy "
+				       "the encrypted content from the lower "
+				       "file whilst inserting the metadata "
+				       "from the xattr into the header; err = "
+				       "[%d]\n", __func__, err);
+				goto out;
+			}
+
+		} else {
+			err = ecryptfs_read_lower_page_segment(folio,
+					folio->index, 0, folio_size(folio),
+					inode);
+			if (err) {
+				printk(KERN_ERR "Error reading page; err = "
+				       "[%d]\n", err);
+				goto out;
+			}
+		}
+	} else {
+		err = ecryptfs_decrypt_page(folio);
+		if (err) {
+			ecryptfs_printk(KERN_ERR, "Error decrypting page; "
+					"err = [%d]\n", err);
+			goto out;
+		}
+	}
+out:
+	ecryptfs_printk(KERN_DEBUG, "Unlocking folio with index = [0x%.16lx]\n",
+			folio->index);
+	folio_end_read(folio, err == 0);
+	return err;
+}
+
+/*
+ * Called with lower inode mutex held.
+ */
+static int fill_zeros_to_end_of_page(struct folio *folio, unsigned int to)
+{
+	struct inode *inode = folio->mapping->host;
+	int end_byte_in_page;
+
+	if ((i_size_read(inode) / PAGE_SIZE) != folio->index)
+		goto out;
+	end_byte_in_page = i_size_read(inode) % PAGE_SIZE;
+	if (to > end_byte_in_page)
+		end_byte_in_page = to;
+	folio_zero_segment(folio, end_byte_in_page, PAGE_SIZE);
+out:
+	return 0;
+}
+
+/**
+ * ecryptfs_write_begin
+ * @iocb: I/O control block for the eCryptfs file
+ * @mapping: The eCryptfs object
+ * @pos: The file offset at which to start writing
+ * @len: Length of the write
+ * @foliop: Pointer to return the folio
+ * @fsdata: Pointer to return fs data (unused)
+ *
+ * This function must zero any hole we create
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_write_begin(const struct kiocb *iocb,
+			struct address_space *mapping,
+			loff_t pos, unsigned len,
+			struct folio **foliop, void **fsdata)
+{
+	pgoff_t index = pos >> PAGE_SHIFT;
+	struct folio *folio;
+	loff_t prev_page_end_size;
+	int rc = 0;
+
+	folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
+			mapping_gfp_mask(mapping));
+	if (IS_ERR(folio))
+		return PTR_ERR(folio);
+	*foliop = folio;
+
+	prev_page_end_size = ((loff_t)index << PAGE_SHIFT);
+	if (!folio_test_uptodate(folio)) {
+		struct ecryptfs_crypt_stat *crypt_stat =
+			&ecryptfs_inode_to_private(mapping->host)->crypt_stat;
+
+		if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
+			rc = ecryptfs_read_lower_page_segment(
+				folio, index, 0, PAGE_SIZE, mapping->host);
+			if (rc) {
+				printk(KERN_ERR "%s: Error attempting to read "
+				       "lower page segment; rc = [%d]\n",
+				       __func__, rc);
+				folio_clear_uptodate(folio);
+				goto out;
+			} else
+				folio_mark_uptodate(folio);
+		} else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
+			if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
+				rc = ecryptfs_copy_up_encrypted_with_header(
+					folio, crypt_stat);
+				if (rc) {
+					printk(KERN_ERR "%s: Error attempting "
+					       "to copy the encrypted content "
+					       "from the lower file whilst "
+					       "inserting the metadata from "
+					       "the xattr into the header; rc "
+					       "= [%d]\n", __func__, rc);
+					folio_clear_uptodate(folio);
+					goto out;
+				}
+				folio_mark_uptodate(folio);
+			} else {
+				rc = ecryptfs_read_lower_page_segment(
+					folio, index, 0, PAGE_SIZE,
+					mapping->host);
+				if (rc) {
+					printk(KERN_ERR "%s: Error reading "
+					       "page; rc = [%d]\n",
+					       __func__, rc);
+					folio_clear_uptodate(folio);
+					goto out;
+				}
+				folio_mark_uptodate(folio);
+			}
+		} else {
+			if (prev_page_end_size
+			    >= i_size_read(mapping->host)) {
+				folio_zero_range(folio, 0, PAGE_SIZE);
+				folio_mark_uptodate(folio);
+			} else if (len < PAGE_SIZE) {
+				rc = ecryptfs_decrypt_page(folio);
+				if (rc) {
+					printk(KERN_ERR "%s: Error decrypting "
+					       "page at index [%ld]; "
+					       "rc = [%d]\n",
+					       __func__, folio->index, rc);
+					folio_clear_uptodate(folio);
+					goto out;
+				}
+				folio_mark_uptodate(folio);
+			}
+		}
+	}
+	/* If creating a page or more of holes, zero them out via truncate.
+	 * Note, this will increase i_size. */
+	if (index != 0) {
+		if (prev_page_end_size > i_size_read(mapping->host)) {
+			rc = ecryptfs_truncate(iocb->ki_filp->f_path.dentry,
+					       prev_page_end_size);
+			if (rc) {
+				printk(KERN_ERR "%s: Error on attempt to "
+				       "truncate to (higher) offset [%lld];"
+				       " rc = [%d]\n", __func__,
+				       prev_page_end_size, rc);
+				goto out;
+			}
+		}
+	}
+	/* Writing to a new page, and creating a small hole from start
+	 * of page?  Zero it out. */
+	if ((i_size_read(mapping->host) == prev_page_end_size)
+	    && (pos != 0))
+		folio_zero_range(folio, 0, PAGE_SIZE);
+out:
+	if (unlikely(rc)) {
+		folio_unlock(folio);
+		folio_put(folio);
+	}
+	return rc;
+}
+
+/*
+ * ecryptfs_write_inode_size_to_header
+ *
+ * Writes the lower file size to the first 8 bytes of the header.
+ *
+ * Returns zero on success; non-zero on error.
+ */
+static int ecryptfs_write_inode_size_to_header(struct inode *ecryptfs_inode)
+{
+	char *file_size_virt;
+	int rc;
+
+	file_size_virt = kmalloc(sizeof(u64), GFP_KERNEL);
+	if (!file_size_virt) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	put_unaligned_be64(i_size_read(ecryptfs_inode), file_size_virt);
+	rc = ecryptfs_write_lower(ecryptfs_inode, file_size_virt, 0,
+				  sizeof(u64));
+	kfree(file_size_virt);
+	if (rc < 0)
+		printk(KERN_ERR "%s: Error writing file size to header; "
+		       "rc = [%d]\n", __func__, rc);
+	else
+		rc = 0;
+out:
+	return rc;
+}
+
+struct kmem_cache *ecryptfs_xattr_cache;
+
+static int ecryptfs_write_inode_size_to_xattr(struct inode *ecryptfs_inode)
+{
+	ssize_t size;
+	void *xattr_virt;
+	struct dentry *lower_dentry =
+		ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_path.dentry;
+	struct inode *lower_inode = d_inode(lower_dentry);
+	int rc;
+
+	if (!(lower_inode->i_opflags & IOP_XATTR)) {
+		printk(KERN_WARNING
+		       "No support for setting xattr in lower filesystem\n");
+		rc = -ENOSYS;
+		goto out;
+	}
+	xattr_virt = kmem_cache_alloc(ecryptfs_xattr_cache, GFP_KERNEL);
+	if (!xattr_virt) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	inode_lock(lower_inode);
+	size = __vfs_getxattr(lower_dentry, lower_inode, ECRYPTFS_XATTR_NAME,
+			      xattr_virt, PAGE_SIZE);
+	if (size < 0)
+		size = 8;
+	put_unaligned_be64(i_size_read(ecryptfs_inode), xattr_virt);
+	rc = __vfs_setxattr(&nop_mnt_idmap, lower_dentry, lower_inode,
+			    ECRYPTFS_XATTR_NAME, xattr_virt, size, 0);
+	inode_unlock(lower_inode);
+	if (rc)
+		printk(KERN_ERR "Error whilst attempting to write inode size "
+		       "to lower file xattr; rc = [%d]\n", rc);
+	kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
+out:
+	return rc;
+}
+
+int ecryptfs_write_inode_size_to_metadata(struct inode *ecryptfs_inode)
+{
+	struct ecryptfs_crypt_stat *crypt_stat;
+
+	crypt_stat = &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
+	BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
+	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
+		return ecryptfs_write_inode_size_to_xattr(ecryptfs_inode);
+	else
+		return ecryptfs_write_inode_size_to_header(ecryptfs_inode);
+}
+
+/**
+ * ecryptfs_write_end
+ * @iocb: I/O control block for the eCryptfs file
+ * @mapping: The eCryptfs object
+ * @pos: The file position
+ * @len: The length of the data (unused)
+ * @copied: The amount of data copied
+ * @folio: The eCryptfs folio
+ * @fsdata: The fsdata (unused)
+ */
+static int ecryptfs_write_end(const struct kiocb *iocb,
+			struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned copied,
+			struct folio *folio, void *fsdata)
+{
+	pgoff_t index = pos >> PAGE_SHIFT;
+	unsigned from = pos & (PAGE_SIZE - 1);
+	unsigned to = from + copied;
+	struct inode *ecryptfs_inode = mapping->host;
+	struct ecryptfs_crypt_stat *crypt_stat =
+		&ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
+	int rc;
+
+	ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page"
+			"(page w/ index = [0x%.16lx], to = [%d])\n", index, to);
+	if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
+		rc = ecryptfs_write_lower_page_segment(ecryptfs_inode,
+				folio, 0, to);
+		if (!rc) {
+			rc = copied;
+			fsstack_copy_inode_size(ecryptfs_inode,
+				ecryptfs_inode_to_lower(ecryptfs_inode));
+		}
+		goto out;
+	}
+	if (!folio_test_uptodate(folio)) {
+		if (copied < PAGE_SIZE) {
+			rc = 0;
+			goto out;
+		}
+		folio_mark_uptodate(folio);
+	}
+	/* Fills in zeros if 'to' goes beyond inode size */
+	rc = fill_zeros_to_end_of_page(folio, to);
+	if (rc) {
+		ecryptfs_printk(KERN_WARNING, "Error attempting to fill "
+			"zeros in page with index = [0x%.16lx]\n", index);
+		goto out;
+	}
+	rc = ecryptfs_encrypt_page(folio);
+	if (rc) {
+		ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper "
+				"index [0x%.16lx])\n", index);
+		goto out;
+	}
+	if (pos + copied > i_size_read(ecryptfs_inode)) {
+		i_size_write(ecryptfs_inode, pos + copied);
+		ecryptfs_printk(KERN_DEBUG, "Expanded file size to "
+			"[0x%.16llx]\n",
+			(unsigned long long)i_size_read(ecryptfs_inode));
+	}
+	rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
+	if (rc)
+		printk(KERN_ERR "Error writing inode size to metadata; "
+		       "rc = [%d]\n", rc);
+	else
+		rc = copied;
+out:
+	folio_unlock(folio);
+	folio_put(folio);
+	return rc;
+}
+
+static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block)
+{
+	struct inode *lower_inode = ecryptfs_inode_to_lower(mapping->host);
+	int ret = bmap(lower_inode, &block);
+
+	if (ret)
+		return 0;
+	return block;
+}
+
+#include <linux/buffer_head.h>
+
+const struct address_space_operations ecryptfs_aops = {
+	/*
+	 * XXX: This is pretty broken for multiple reasons: ecryptfs does not
+	 * actually use buffer_heads, and ecryptfs will crash without
+	 * CONFIG_BLOCK.  But it matches the behavior before the default for
+	 * address_space_operations without the ->dirty_folio method was
+	 * cleaned up, so this is the best we can do without maintainer
+	 * feedback.
+	 */
+#ifdef CONFIG_BLOCK
+	.dirty_folio	= block_dirty_folio,
+	.invalidate_folio = block_invalidate_folio,
+#endif
+	.writepages = ecryptfs_writepages,
+	.read_folio = ecryptfs_read_folio,
+	.write_begin = ecryptfs_write_begin,
+	.write_end = ecryptfs_write_end,
+	.migrate_folio = filemap_migrate_folio,
+	.bmap = ecryptfs_bmap,
+};

linux-7.2.3/fs/ecryptfs/read_write.c

@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 2007 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ */
+
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/sched/signal.h>
+
+#include "ecryptfs_kernel.h"
+
+/**
+ * ecryptfs_write_lower
+ * @ecryptfs_inode: The eCryptfs inode
+ * @data: Data to write
+ * @offset: Byte offset in the lower file to which to write the data
+ * @size: Number of bytes from @data to write at @offset in the lower
+ *        file
+ *
+ * Write data to the lower file.
+ *
+ * Returns bytes written on success; less than zero on error
+ */
+int ecryptfs_write_lower(struct inode *ecryptfs_inode, char *data,
+			 loff_t offset, size_t size)
+{
+	struct file *lower_file;
+	ssize_t rc;
+
+	lower_file = ecryptfs_inode_to_private(ecryptfs_inode)->lower_file;
+	if (!lower_file)
+		return -EIO;
+	rc = kernel_write(lower_file, data, size, &offset);
+	mark_inode_dirty_sync(ecryptfs_inode);
+	return rc;
+}
+
+/**
+ * ecryptfs_write_lower_page_segment
+ * @ecryptfs_inode: The eCryptfs inode
+ * @folio_for_lower: The folio containing the data to be written to the
+ *                  lower file
+ * @offset_in_page: The offset in the @folio_for_lower from which to
+ *                  start writing the data
+ * @size: The amount of data from @folio_for_lower to write to the
+ *        lower file
+ *
+ * Determines the byte offset in the file for the given page and
+ * offset within the page, maps the page, and makes the call to write
+ * the contents of @folio_for_lower to the lower inode.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode,
+				      struct folio *folio_for_lower,
+				      size_t offset_in_page, size_t size)
+{
+	char *virt;
+	loff_t offset;
+	int rc;
+
+	offset = (loff_t)folio_for_lower->index * PAGE_SIZE + offset_in_page;
+	virt = kmap_local_folio(folio_for_lower, 0);
+	rc = ecryptfs_write_lower(ecryptfs_inode, virt, offset, size);
+	if (rc > 0)
+		rc = 0;
+	kunmap_local(virt);
+	return rc;
+}
+
+/**
+ * ecryptfs_write
+ * @ecryptfs_inode: The eCryptfs file into which to write
+ * @data: Virtual address where data to write is located
+ * @offset: Offset in the eCryptfs file at which to begin writing the
+ *          data from @data
+ * @size: The number of bytes to write from @data
+ *
+ * Write an arbitrary amount of data to an arbitrary location in the
+ * eCryptfs inode page cache. This is done on a page-by-page, and then
+ * by an extent-by-extent, basis; individual extents are encrypted and
+ * written to the lower page cache (via VFS writes). This function
+ * takes care of all the address translation to locations in the lower
+ * filesystem; it also handles truncate events, writing out zeros
+ * where necessary.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
+		   size_t size)
+{
+	struct ecryptfs_crypt_stat *crypt_stat;
+	char *ecryptfs_page_virt;
+	loff_t ecryptfs_file_size = i_size_read(ecryptfs_inode);
+	loff_t data_offset = 0;
+	loff_t pos;
+	int rc = 0;
+
+	crypt_stat = &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
+	/*
+	 * if we are writing beyond current size, then start pos
+	 * at the current size - we'll fill in zeros from there.
+	 */
+	if (offset > ecryptfs_file_size)
+		pos = ecryptfs_file_size;
+	else
+		pos = offset;
+	while (pos < (offset + size)) {
+		struct folio *ecryptfs_folio;
+		pgoff_t ecryptfs_page_idx = (pos >> PAGE_SHIFT);
+		size_t start_offset_in_page = (pos & ~PAGE_MASK);
+		size_t num_bytes = (PAGE_SIZE - start_offset_in_page);
+		loff_t total_remaining_bytes = ((offset + size) - pos);
+
+		if (fatal_signal_pending(current)) {
+			rc = -EINTR;
+			break;
+		}
+
+		if (num_bytes > total_remaining_bytes)
+			num_bytes = total_remaining_bytes;
+		if (pos < offset) {
+			/* remaining zeros to write, up to destination offset */
+			loff_t total_remaining_zeros = (offset - pos);
+
+			if (num_bytes > total_remaining_zeros)
+				num_bytes = total_remaining_zeros;
+		}
+		ecryptfs_folio = read_mapping_folio(ecryptfs_inode->i_mapping,
+				ecryptfs_page_idx, NULL);
+		if (IS_ERR(ecryptfs_folio)) {
+			rc = PTR_ERR(ecryptfs_folio);
+			printk(KERN_ERR "%s: Error getting page at "
+			       "index [%ld] from eCryptfs inode "
+			       "mapping; rc = [%d]\n", __func__,
+			       ecryptfs_page_idx, rc);
+			goto out;
+		}
+		folio_lock(ecryptfs_folio);
+		ecryptfs_page_virt = kmap_local_folio(ecryptfs_folio, 0);
+
+		/*
+		 * pos: where we're now writing, offset: where the request was
+		 * If current pos is before request, we are filling zeros
+		 * If we are at or beyond request, we are writing the *data*
+		 * If we're in a fresh page beyond eof, zero it in either case
+		 */
+		if (pos < offset || !start_offset_in_page) {
+			/* We are extending past the previous end of the file.
+			 * Fill in zero values to the end of the page */
+			memset(((char *)ecryptfs_page_virt
+				+ start_offset_in_page), 0,
+				PAGE_SIZE - start_offset_in_page);
+		}
+
+		/* pos >= offset, we are now writing the data request */
+		if (pos >= offset) {
+			memcpy(((char *)ecryptfs_page_virt
+				+ start_offset_in_page),
+			       (data + data_offset), num_bytes);
+			data_offset += num_bytes;
+		}
+		kunmap_local(ecryptfs_page_virt);
+		flush_dcache_folio(ecryptfs_folio);
+		folio_mark_uptodate(ecryptfs_folio);
+		folio_unlock(ecryptfs_folio);
+		if (crypt_stat->flags & ECRYPTFS_ENCRYPTED)
+			rc = ecryptfs_encrypt_page(ecryptfs_folio);
+		else
+			rc = ecryptfs_write_lower_page_segment(ecryptfs_inode,
+						ecryptfs_folio,
+						start_offset_in_page,
+						data_offset);
+		folio_put(ecryptfs_folio);
+		if (rc) {
+			printk(KERN_ERR "%s: Error encrypting "
+			       "page; rc = [%d]\n", __func__, rc);
+			goto out;
+		}
+		pos += num_bytes;
+	}
+	if (pos > ecryptfs_file_size) {
+		i_size_write(ecryptfs_inode, pos);
+		if (crypt_stat->flags & ECRYPTFS_ENCRYPTED) {
+			int rc2;
+
+			rc2 = ecryptfs_write_inode_size_to_metadata(
+								ecryptfs_inode);
+			if (rc2) {
+				printk(KERN_ERR	"Problem with "
+				       "ecryptfs_write_inode_size_to_metadata; "
+				       "rc = [%d]\n", rc2);
+				if (!rc)
+					rc = rc2;
+				goto out;
+			}
+		}
+	}
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_read_lower
+ * @data: The read data is stored here by this function
+ * @offset: Byte offset in the lower file from which to read the data
+ * @size: Number of bytes to read from @offset of the lower file and
+ *        store into @data
+ * @ecryptfs_inode: The eCryptfs inode
+ *
+ * Read @size bytes of data at byte offset @offset from the lower
+ * inode into memory location @data.
+ *
+ * Returns bytes read on success; 0 on EOF; less than zero on error
+ */
+int ecryptfs_read_lower(char *data, loff_t offset, size_t size,
+			struct inode *ecryptfs_inode)
+{
+	struct file *lower_file;
+	lower_file = ecryptfs_inode_to_private(ecryptfs_inode)->lower_file;
+	if (!lower_file)
+		return -EIO;
+	return kernel_read(lower_file, data, size, &offset);
+}
+
+/**
+ * ecryptfs_read_lower_page_segment
+ * @folio_for_ecryptfs: The folio into which data for eCryptfs will be
+ *                     written
+ * @page_index: Page index in @page_for_ecryptfs from which to start
+ *		writing
+ * @offset_in_page: Offset in @page_for_ecryptfs from which to start
+ *                  writing
+ * @size: The number of bytes to write into @page_for_ecryptfs
+ * @ecryptfs_inode: The eCryptfs inode
+ *
+ * Determines the byte offset in the file for the given page and
+ * offset within the page, maps the page, and makes the call to read
+ * the contents of @page_for_ecryptfs from the lower inode.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_read_lower_page_segment(struct folio *folio_for_ecryptfs,
+				     pgoff_t page_index,
+				     size_t offset_in_page, size_t size,
+				     struct inode *ecryptfs_inode)
+{
+	char *virt;
+	loff_t offset;
+	int rc;
+
+	offset = (loff_t)page_index * PAGE_SIZE + offset_in_page;
+	virt = kmap_local_folio(folio_for_ecryptfs, 0);
+	rc = ecryptfs_read_lower(virt, offset, size, ecryptfs_inode);
+	if (rc > 0)
+		rc = 0;
+	kunmap_local(virt);
+	flush_dcache_folio(folio_for_ecryptfs);
+	return rc;
+}

linux-7.2.3/fs/ecryptfs/super.c

@@ -0,0 +1,174 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 1997-2003 Erez Zadok
+ * Copyright (C) 2001-2003 Stony Brook University
+ * Copyright (C) 2004-2006 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ *              Michael C. Thompson <mcthomps@us.ibm.com>
+ */
+
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/key.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/file.h>
+#include <linux/statfs.h>
+#include <linux/magic.h>
+#include "ecryptfs_kernel.h"
+
+struct kmem_cache *ecryptfs_inode_info_cache;
+
+/**
+ * ecryptfs_alloc_inode - allocate an ecryptfs inode
+ * @sb: Pointer to the ecryptfs super block
+ *
+ * Called to bring an inode into existence.
+ *
+ * Only handle allocation, setting up structures should be done in
+ * ecryptfs_read_inode. This is because the kernel, between now and
+ * then, will 0 out the private data pointer.
+ *
+ * Returns a pointer to a newly allocated inode, NULL otherwise
+ */
+static struct inode *ecryptfs_alloc_inode(struct super_block *sb)
+{
+	struct ecryptfs_inode_info *inode_info;
+	struct inode *inode = NULL;
+
+	inode_info = alloc_inode_sb(sb, ecryptfs_inode_info_cache, GFP_KERNEL);
+	if (unlikely(!inode_info))
+		goto out;
+	ecryptfs_init_crypt_stat(&inode_info->crypt_stat);
+	mutex_init(&inode_info->lower_file_mutex);
+	atomic_set(&inode_info->lower_file_count, 0);
+	inode_info->lower_file = NULL;
+	inode = &inode_info->vfs_inode;
+out:
+	return inode;
+}
+
+static void ecryptfs_free_inode(struct inode *inode)
+{
+	struct ecryptfs_inode_info *inode_info;
+	inode_info = ecryptfs_inode_to_private(inode);
+
+	kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
+}
+
+/**
+ * ecryptfs_destroy_inode
+ * @inode: The ecryptfs inode
+ *
+ * This is used during the final destruction of the inode.  All
+ * allocation of memory related to the inode, including allocated
+ * memory in the crypt_stat struct, will be released here.
+ * There should be no chance that this deallocation will be missed.
+ */
+static void ecryptfs_destroy_inode(struct inode *inode)
+{
+	struct ecryptfs_inode_info *inode_info;
+
+	inode_info = ecryptfs_inode_to_private(inode);
+	BUG_ON(inode_info->lower_file);
+	ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat);
+}
+
+/**
+ * ecryptfs_statfs
+ * @dentry: The ecryptfs dentry
+ * @buf: The struct kstatfs to fill in with stats
+ *
+ * Get the filesystem statistics. Currently, we let this pass right through
+ * to the lower filesystem and take no action ourselves.
+ */
+static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	int rc;
+
+	if (!lower_dentry->d_sb->s_op->statfs)
+		return -ENOSYS;
+
+	rc = lower_dentry->d_sb->s_op->statfs(lower_dentry, buf);
+	if (rc)
+		return rc;
+
+	buf->f_type = ECRYPTFS_SUPER_MAGIC;
+	rc = ecryptfs_set_f_namelen(&buf->f_namelen, buf->f_namelen,
+	       &ecryptfs_superblock_to_private(dentry->d_sb)->mount_crypt_stat);
+
+	return rc;
+}
+
+/**
+ * ecryptfs_evict_inode
+ * @inode: The ecryptfs inode
+ *
+ * Called by iput() when the inode reference count reached zero
+ * and the inode is not hashed anywhere.  Used to clear anything
+ * that needs to be, before the inode is completely destroyed and put
+ * on the inode free list. We use this to drop out reference to the
+ * lower inode.
+ */
+static void ecryptfs_evict_inode(struct inode *inode)
+{
+	truncate_inode_pages_final(&inode->i_data);
+	clear_inode(inode);
+	iput(ecryptfs_inode_to_lower(inode));
+}
+
+/*
+ * ecryptfs_show_options
+ *
+ * Prints the mount options for a given superblock.
+ * Returns zero; does not fail.
+ */
+static int ecryptfs_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct super_block *sb = root->d_sb;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
+		&ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
+	struct ecryptfs_global_auth_tok *walker;
+
+	mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
+	list_for_each_entry(walker,
+			    &mount_crypt_stat->global_auth_tok_list,
+			    mount_crypt_stat_list) {
+		if (walker->flags & ECRYPTFS_AUTH_TOK_FNEK)
+			seq_printf(m, ",ecryptfs_fnek_sig=%s", walker->sig);
+		else
+			seq_printf(m, ",ecryptfs_sig=%s", walker->sig);
+	}
+	mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
+
+	seq_printf(m, ",ecryptfs_cipher=%s",
+		mount_crypt_stat->global_default_cipher_name);
+
+	if (mount_crypt_stat->global_default_cipher_key_size)
+		seq_printf(m, ",ecryptfs_key_bytes=%zd",
+			   mount_crypt_stat->global_default_cipher_key_size);
+	if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)
+		seq_printf(m, ",ecryptfs_passthrough");
+	if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
+		seq_printf(m, ",ecryptfs_xattr_metadata");
+	if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
+		seq_printf(m, ",ecryptfs_encrypted_view");
+	if (mount_crypt_stat->flags & ECRYPTFS_UNLINK_SIGS)
+		seq_printf(m, ",ecryptfs_unlink_sigs");
+	if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
+		seq_printf(m, ",ecryptfs_mount_auth_tok_only");
+
+	return 0;
+}
+
+const struct super_operations ecryptfs_sops = {
+	.alloc_inode = ecryptfs_alloc_inode,
+	.destroy_inode = ecryptfs_destroy_inode,
+	.free_inode = ecryptfs_free_inode,
+	.statfs = ecryptfs_statfs,
+	.evict_inode = ecryptfs_evict_inode,
+	.show_options = ecryptfs_show_options
+};