Resguardo inicial

linux-7.2.3/security/smack/Kconfig

@@ -0,0 +1,55 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config SECURITY_SMACK
+	bool "Simplified Mandatory Access Control Kernel Support"
+	depends on NET
+	depends on INET
+	depends on SECURITY
+	select NETLABEL
+	select SECURITY_NETWORK
+	default n
+	help
+	  This selects the Simplified Mandatory Access Control Kernel.
+	  Smack is useful for sensitivity, integrity, and a variety
+	  of other mandatory security schemes.
+	  If you are unsure how to answer this question, answer N.
+
+config SECURITY_SMACK_BRINGUP
+	bool "Reporting on access granted by Smack rules"
+	depends on SECURITY_SMACK
+	default n
+	help
+	  Enable the bring-up ("b") access mode in Smack rules.
+	  When access is granted by a rule with the "b" mode a
+	  message about the access requested is generated. The
+	  intention is that a process can be granted a wide set
+	  of access initially with the bringup mode set on the
+	  rules. The developer can use the information to
+	  identify which rules are necessary and what accesses
+	  may be inappropriate. The developer can reduce the
+	  access rule set once the behavior is well understood.
+	  This is a superior mechanism to the oft abused
+	  "permissive" mode of other systems.
+	  If you are unsure how to answer this question, answer N.
+
+config SECURITY_SMACK_NETFILTER
+	bool "Packet marking using secmarks for netfilter"
+	depends on SECURITY_SMACK
+	depends on NETWORK_SECMARK
+	depends on NETFILTER
+	default n
+	help
+	  This enables security marking of network packets using
+	  Smack labels.
+	  If you are unsure how to answer this question, answer N.
+
+config SECURITY_SMACK_APPEND_SIGNALS
+	bool "Treat delivering signals as an append operation"
+	depends on SECURITY_SMACK
+	default n
+	help
+	  Sending a signal has been treated as a write operation to the
+	  receiving process. If this option is selected, the delivery
+	  will be an append operation instead. This makes it possible
+	  to differentiate between delivering a network packet and
+	  delivering a signal in the Smack rules.
+	  If you are unsure how to answer this question, answer N.

linux-7.2.3/security/smack/Makefile

@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for the SMACK LSM
+#
+
+obj-$(CONFIG_SECURITY_SMACK) := smack.o
+
+smack-y := smack_lsm.o smack_access.o smackfs.o
+smack-$(CONFIG_SECURITY_SMACK_NETFILTER) += smack_netfilter.o

linux-7.2.3/security/smack/smack.h

@@ -0,0 +1,541 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
+ *
+ * Author:
+ *      Casey Schaufler <casey@schaufler-ca.com>
+ */
+
+#ifndef _SECURITY_SMACK_H
+#define _SECURITY_SMACK_H
+
+#include <linux/capability.h>
+#include <linux/spinlock.h>
+#include <linux/lsm_hooks.h>
+#include <linux/in.h>
+#if IS_ENABLED(CONFIG_IPV6)
+#include <linux/in6.h>
+#endif /* CONFIG_IPV6 */
+#include <net/netlabel.h>
+#include <linux/list.h>
+#include <linux/rculist.h>
+#include <linux/lsm_audit.h>
+#include <linux/msg.h>
+
+/*
+ * Use IPv6 port labeling if IPv6 is enabled and secmarks
+ * are not being used.
+ */
+#if IS_ENABLED(CONFIG_IPV6) && !defined(CONFIG_SECURITY_SMACK_NETFILTER)
+#define SMACK_IPV6_PORT_LABELING 1
+#endif
+
+#if IS_ENABLED(CONFIG_IPV6) && defined(CONFIG_SECURITY_SMACK_NETFILTER)
+#define SMACK_IPV6_SECMARK_LABELING 1
+#endif
+
+/*
+ * Smack labels were limited to 23 characters for a long time.
+ */
+#define SMK_LABELLEN	24
+#define SMK_LONGLABEL	256
+
+/*
+ * This is the repository for labels seen so that it is
+ * not necessary to keep allocating tiny chunks of memory
+ * and so that they can be shared.
+ *
+ * Labels are never modified in place. Anytime a label
+ * is imported (e.g. xattrset on a file) the list is checked
+ * for it and it is added if it doesn't exist. The address
+ * is passed out in either case. Entries are added, but
+ * never deleted.
+ *
+ * Since labels are hanging around anyway it doesn't
+ * hurt to maintain a secid for those awkward situations
+ * where kernel components that ought to use LSM independent
+ * interfaces don't. The secid should go away when all of
+ * these components have been repaired.
+ *
+ * The cipso value associated with the label gets stored here, too.
+ *
+ * Keep the access rules for this subject label here so that
+ * the entire set of rules does not need to be examined every
+ * time.
+ */
+struct smack_known {
+	struct list_head		list;
+	struct hlist_node		smk_hashed;
+	char				*smk_known;
+	u32				smk_secid;
+	struct netlbl_lsm_secattr	smk_netlabel;	/* on wire labels */
+	struct list_head		smk_rules;	/* access rules */
+	struct mutex			smk_rules_lock;	/* lock for rules */
+};
+
+/*
+ * Maximum number of bytes for the levels in a CIPSO IP option.
+ * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
+ * bigger than can be used, and 24 is the next lower multiple
+ * of 8, and there are too many issues if there isn't space set
+ * aside for the terminating null byte.
+ */
+#define SMK_CIPSOLEN	24
+
+struct superblock_smack {
+	struct smack_known	*smk_root;
+	struct smack_known	*smk_floor;
+	struct smack_known	*smk_hat;
+	struct smack_known	*smk_default;
+	int			smk_flags;
+};
+
+/*
+ * Superblock flags
+ */
+#define SMK_SB_INITIALIZED	0x01
+#define SMK_SB_UNTRUSTED	0x02
+
+struct socket_smack {
+	struct smack_known	*smk_out;	/* outbound label */
+	struct smack_known	*smk_in;	/* inbound label */
+	struct smack_known	*smk_packet;	/* TCP peer label */
+	int			smk_state;	/* netlabel socket states */
+};
+#define	SMK_NETLBL_UNSET	0
+#define	SMK_NETLBL_UNLABELED	1
+#define	SMK_NETLBL_LABELED	2
+#define	SMK_NETLBL_REQSKB	3
+
+/*
+ * Inode smack data
+ */
+struct inode_smack {
+	struct smack_known	*smk_inode;	/* label of the fso */
+	struct smack_known	*smk_task;	/* label of the task */
+	struct smack_known	*smk_mmap;	/* label of the mmap domain */
+	int			smk_flags;	/* smack inode flags */
+};
+
+struct task_smack {
+	struct smack_known	*smk_task;	/* label for access control */
+	struct smack_known	*smk_forked;	/* label when forked */
+	struct smack_known	*smk_transmuted;/* label when transmuted */
+	struct list_head	smk_rules;	/* per task access rules */
+	struct mutex		smk_rules_lock;	/* lock for the rules */
+	struct list_head	smk_relabel;	/* transit allowed labels */
+};
+
+#define	SMK_INODE_INSTANT	0x01	/* inode is instantiated */
+#define	SMK_INODE_TRANSMUTE	0x02	/* directory is transmuting */
+#define	SMK_INODE_CHANGED	0x04	/* smack was transmuted (unused) */
+#define	SMK_INODE_IMPURE	0x08	/* involved in an impure transaction */
+
+/*
+ * A label access rule.
+ */
+struct smack_rule {
+	struct list_head	list;
+	struct smack_known	*smk_subject;
+	struct smack_known	*smk_object;
+	int			smk_access;
+};
+
+/*
+ * An entry in the table identifying IPv4 hosts.
+ */
+struct smk_net4addr {
+	struct list_head	list;
+	struct in_addr		smk_host;	/* network address */
+	struct in_addr		smk_mask;	/* network mask */
+	int			smk_masks;	/* mask size */
+	struct smack_known	*smk_label;	/* label */
+};
+
+#if IS_ENABLED(CONFIG_IPV6)
+/*
+ * An entry in the table identifying IPv6 hosts.
+ */
+struct smk_net6addr {
+	struct list_head	list;
+	struct in6_addr		smk_host;	/* network address */
+	struct in6_addr		smk_mask;	/* network mask */
+	int			smk_masks;	/* mask size */
+	struct smack_known	*smk_label;	/* label */
+};
+#endif /* CONFIG_IPV6 */
+
+#ifdef SMACK_IPV6_PORT_LABELING
+/*
+ * An entry in the table identifying ports.
+ */
+struct smk_port_label {
+	struct list_head	list;
+	struct sock		*smk_sock;	/* socket initialized on */
+	unsigned short		smk_port;	/* the port number */
+	struct smack_known	*smk_in;	/* inbound label */
+	struct smack_known	*smk_out;	/* outgoing label */
+	short			smk_sock_type;	/* Socket type */
+	short			smk_can_reuse;
+};
+#endif /* SMACK_IPV6_PORT_LABELING */
+
+struct smack_known_list_elem {
+	struct list_head	list;
+	struct smack_known	*smk_label;
+};
+
+enum {
+	Opt_error = -1,
+	Opt_fsdefault = 0,
+	Opt_fsfloor = 1,
+	Opt_fshat = 2,
+	Opt_fsroot = 3,
+	Opt_fstransmute = 4,
+};
+
+#define SMACK_DELETE_OPTION	"-DELETE"
+#define SMACK_CIPSO_OPTION 	"-CIPSO"
+
+/*
+ * CIPSO defaults.
+ */
+#define SMACK_CIPSO_DOI_DEFAULT		3	/* Historical */
+#define SMACK_CIPSO_DOI_INVALID		-1	/* Not a DOI */
+#define SMACK_CIPSO_DIRECT_DEFAULT	250	/* Arbitrary */
+#define SMACK_CIPSO_MAPPED_DEFAULT	251	/* Also arbitrary */
+#define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
+/*
+ * CIPSO 2.2 standard is 239, but Smack wants to use the
+ * categories in a structured way that limits the value to
+ * the bits in 23 bytes, hence the unusual number.
+ */
+#define SMACK_CIPSO_MAXCATNUM           184     /* 23 * 8 */
+
+/*
+ * Ptrace rules
+ */
+#define SMACK_PTRACE_DEFAULT	0
+#define SMACK_PTRACE_EXACT	1
+#define SMACK_PTRACE_DRACONIAN	2
+#define SMACK_PTRACE_MAX	SMACK_PTRACE_DRACONIAN
+
+/*
+ * Flags for untraditional access modes.
+ * It shouldn't be necessary to avoid conflicts with definitions
+ * in fs.h, but do so anyway.
+ */
+#define MAY_TRANSMUTE	0x00001000	/* Controls directory labeling */
+#define MAY_LOCK	0x00002000	/* Locks should be writes, but ... */
+#define MAY_BRINGUP	0x00004000	/* Report use of this rule */
+
+/*
+ * The policy for delivering signals is configurable.
+ * It is usually "write", but can be "append".
+ */
+#ifdef CONFIG_SECURITY_SMACK_APPEND_SIGNALS
+#define MAY_DELIVER	MAY_APPEND	/* Signal delivery requires append */
+#else
+#define MAY_DELIVER	MAY_WRITE	/* Signal delivery requires write */
+#endif
+
+#define SMACK_BRINGUP_ALLOW		1	/* Allow bringup mode */
+#define SMACK_UNCONFINED_SUBJECT	2	/* Allow unconfined label */
+#define SMACK_UNCONFINED_OBJECT		3	/* Allow unconfined label */
+
+/*
+ * Just to make the common cases easier to deal with
+ */
+#define MAY_ANYREAD	(MAY_READ | MAY_EXEC)
+#define MAY_READWRITE	(MAY_READ | MAY_WRITE)
+#define MAY_NOT		0
+
+/*
+ * Number of access types used by Smack (rwxatlb)
+ */
+#define SMK_NUM_ACCESS_TYPE 7
+
+/* SMACK data */
+struct smack_audit_data {
+	const char *function;
+	char *subject;
+	char *object;
+	char *request;
+	int result;
+};
+
+/*
+ * Smack audit data; is empty if CONFIG_AUDIT not set
+ * to save some stack
+ */
+struct smk_audit_info {
+#ifdef CONFIG_AUDIT
+	struct common_audit_data a;
+	struct smack_audit_data sad;
+#endif
+};
+
+/*
+ * Initialization
+ */
+#if defined(CONFIG_SECURITY_SMACK_NETFILTER)
+int smack_nf_ip_init(void);
+#else
+static inline int smack_nf_ip_init(void)
+{
+	return 0;
+}
+#endif
+int init_smk_fs(void);
+int smack_initcall(void);
+
+/*
+ * These functions are in smack_access.c
+ */
+int smk_access_entry(char *, char *, struct list_head *);
+int smk_access(struct smack_known *, struct smack_known *,
+	       int, struct smk_audit_info *);
+int smk_tskacc(struct task_smack *, struct smack_known *,
+	       u32, struct smk_audit_info *);
+int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
+int smack_str_from_perm(char *string, int access);
+struct smack_known *smack_from_secid(const u32);
+int smk_parse_label_len(const char *string, int len);
+char *smk_parse_smack(const char *string, int len);
+int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
+struct smack_known *smk_import_entry(const char *, int);
+struct smack_known *smk_import_valid_label(const char *label, int label_len,
+					   gfp_t gfp);
+void smk_insert_entry(struct smack_known *skp);
+struct smack_known *smk_find_entry(const char *);
+bool smack_privileged(int cap);
+bool smack_privileged_cred(int cap, const struct cred *cred);
+void smk_destroy_label_list(struct list_head *list);
+int smack_populate_secattr(struct smack_known *skp);
+
+/*
+ * Shared data.
+ */
+extern int smack_enabled __initdata;
+extern int smack_cipso_direct;
+extern int smack_cipso_mapped;
+extern struct smack_known *smack_net_ambient;
+extern struct smack_known *smack_syslog_label;
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+extern struct smack_known *smack_unconfined;
+#endif
+extern int smack_ptrace_rule;
+extern struct lsm_blob_sizes smack_blob_sizes;
+
+extern struct smack_known smack_known_floor;
+extern struct smack_known smack_known_hat;
+extern struct smack_known smack_known_huh;
+extern struct smack_known smack_known_star;
+extern struct smack_known smack_known_web;
+
+extern struct mutex	smack_known_lock;
+extern struct list_head smack_known_list;
+extern struct list_head smk_net4addr_list;
+#if IS_ENABLED(CONFIG_IPV6)
+extern struct list_head smk_net6addr_list;
+#endif /* CONFIG_IPV6 */
+
+extern struct mutex     smack_onlycap_lock;
+extern struct list_head smack_onlycap_list;
+
+#define SMACK_HASH_SLOTS 16
+extern struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
+extern struct kmem_cache *smack_rule_cache;
+
+static inline struct task_smack *smack_cred(const struct cred *cred)
+{
+	return cred->security + smack_blob_sizes.lbs_cred;
+}
+
+static inline struct smack_known **smack_file(const struct file *file)
+{
+	return (struct smack_known **)(file->f_security +
+				       smack_blob_sizes.lbs_file);
+}
+
+static inline struct inode_smack *smack_inode(const struct inode *inode)
+{
+	return inode->i_security + smack_blob_sizes.lbs_inode;
+}
+
+static inline struct smack_known **smack_msg_msg(const struct msg_msg *msg)
+{
+	return msg->security + smack_blob_sizes.lbs_msg_msg;
+}
+
+static inline struct smack_known **smack_ipc(const struct kern_ipc_perm *ipc)
+{
+	return ipc->security + smack_blob_sizes.lbs_ipc;
+}
+
+static inline struct superblock_smack *smack_superblock(
+					const struct super_block *superblock)
+{
+	return superblock->s_security + smack_blob_sizes.lbs_superblock;
+}
+
+static inline struct socket_smack *smack_sock(const struct sock *sock)
+{
+	return sock->sk_security + smack_blob_sizes.lbs_sock;
+}
+
+#ifdef CONFIG_KEYS
+static inline struct smack_known **smack_key(const struct key *key)
+{
+	return key->security + smack_blob_sizes.lbs_key;
+}
+#endif /* CONFIG_KEYS */
+
+/*
+ * Is the directory transmuting?
+ */
+static inline int smk_inode_transmutable(const struct inode *isp)
+{
+	struct inode_smack *sip = smack_inode(isp);
+	return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
+}
+
+/*
+ * Present a pointer to the smack label entry in an inode blob.
+ */
+static inline struct smack_known *smk_of_inode(const struct inode *isp)
+{
+	struct inode_smack *sip = smack_inode(isp);
+	return sip->smk_inode;
+}
+
+/*
+ * Present a pointer to the smack label entry in an task blob.
+ */
+static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
+{
+	return tsp->smk_task;
+}
+
+static inline struct smack_known *smk_of_task_struct_obj(
+						const struct task_struct *t)
+{
+	struct smack_known *skp;
+	const struct cred *cred;
+
+	rcu_read_lock();
+
+	cred = __task_cred(t);
+	skp = smk_of_task(smack_cred(cred));
+
+	rcu_read_unlock();
+
+	return skp;
+}
+
+/*
+ * Present a pointer to the forked smack label entry in an task blob.
+ */
+static inline struct smack_known *smk_of_forked(const struct task_smack *tsp)
+{
+	return tsp->smk_forked;
+}
+
+/*
+ * Present a pointer to the smack label in the current task blob.
+ */
+static inline struct smack_known *smk_of_current(void)
+{
+	return smk_of_task(smack_cred(current_cred()));
+}
+
+void smack_log(char *subject_label, char *object_label,
+		int request,
+		int result, struct smk_audit_info *auditdata);
+
+#ifdef CONFIG_AUDIT
+
+/*
+ * logging functions
+ */
+#define SMACK_AUDIT_DENIED 0x1
+#define SMACK_AUDIT_ACCEPT 0x2
+extern int log_policy;
+
+/*
+ * some inline functions to set up audit data
+ * they do nothing if CONFIG_AUDIT is not set
+ *
+ */
+static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
+			       char type)
+{
+	memset(&a->sad, 0, sizeof(a->sad));
+	a->a.type = type;
+	a->a.smack_audit_data = &a->sad;
+	a->a.smack_audit_data->function = func;
+}
+
+static inline void smk_ad_init_net(struct smk_audit_info *a, const char *func,
+				   char type, struct lsm_network_audit *net)
+{
+	smk_ad_init(a, func, type);
+	memset(net, 0, sizeof(*net));
+	a->a.u.net = net;
+}
+
+static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
+					 struct task_struct *t)
+{
+	a->a.u.tsk = t;
+}
+static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
+						    struct dentry *d)
+{
+	a->a.u.dentry = d;
+}
+static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
+					      struct inode *i)
+{
+	a->a.u.inode = i;
+}
+static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
+					     struct path p)
+{
+	a->a.u.path = p;
+}
+static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
+					    struct sock *sk)
+{
+	a->a.u.net->sk = sk;
+}
+
+#else /* no AUDIT */
+
+static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
+			       char type)
+{
+}
+static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
+					 struct task_struct *t)
+{
+}
+static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
+						    struct dentry *d)
+{
+}
+static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
+					      struct inode *i)
+{
+}
+static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
+					     struct path p)
+{
+}
+static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
+					    struct sock *sk)
+{
+}
+#endif
+
+#endif  /* _SECURITY_SMACK_H */

linux-7.2.3/security/smack/smack_access.c

@@ -0,0 +1,756 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
+ *
+ * Author:
+ *      Casey Schaufler <casey@schaufler-ca.com>
+ */
+
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include "smack.h"
+
+struct smack_known smack_known_huh = {
+	.smk_known	= "?",
+	.smk_secid	= 2,
+};
+
+struct smack_known smack_known_hat = {
+	.smk_known	= "^",
+	.smk_secid	= 3,
+};
+
+struct smack_known smack_known_star = {
+	.smk_known	= "*",
+	.smk_secid	= 4,
+};
+
+struct smack_known smack_known_floor = {
+	.smk_known	= "_",
+	.smk_secid	= 5,
+};
+
+struct smack_known smack_known_web = {
+	.smk_known	= "@",
+	.smk_secid	= 7,
+};
+
+LIST_HEAD(smack_known_list);
+
+/*
+ * The initial value needs to be bigger than any of the
+ * known values above.
+ */
+static u32 smack_next_secid = 10;
+
+#ifdef CONFIG_AUDIT
+/*
+ * what events do we log
+ * can be overwritten at run-time by /smack/logging
+ */
+int log_policy = SMACK_AUDIT_DENIED;
+#endif /* CONFIG_AUDIT */
+
+/**
+ * smk_access_entry - look up matching access rule
+ * @subject_label: a pointer to the subject's Smack label
+ * @object_label: a pointer to the object's Smack label
+ * @rule_list: the list of rules to search
+ *
+ * This function looks up the subject/object pair in the
+ * access rule list and returns the access mode. If no
+ * entry is found returns -ENOENT.
+ *
+ * NOTE:
+ *
+ * Earlier versions of this function allowed for labels that
+ * were not on the label list. This was done to allow for
+ * labels to come over the network that had never been seen
+ * before on this host. Unless the receiving socket has the
+ * star label this will always result in a failure check. The
+ * star labeled socket case is now handled in the networking
+ * hooks so there is no case where the label is not on the
+ * label list. Checking to see if the address of two labels
+ * is the same is now a reliable test.
+ *
+ * Do the object check first because that is more
+ * likely to differ.
+ *
+ * Allowing write access implies allowing locking.
+ */
+int smk_access_entry(char *subject_label, char *object_label,
+			struct list_head *rule_list)
+{
+	struct smack_rule *srp;
+
+	list_for_each_entry_rcu(srp, rule_list, list) {
+		if (srp->smk_object->smk_known == object_label &&
+		    srp->smk_subject->smk_known == subject_label) {
+			int may = srp->smk_access;
+			/*
+			 * MAY_WRITE implies MAY_LOCK.
+			 */
+			if ((may & MAY_WRITE) == MAY_WRITE)
+				may |= MAY_LOCK;
+			return may;
+		}
+	}
+
+	return -ENOENT;
+}
+
+/**
+ * smk_access - determine if a subject has a specific access to an object
+ * @subject: a pointer to the subject's Smack label entry
+ * @object: a pointer to the object's Smack label entry
+ * @request: the access requested, in "MAY" format
+ * @a : a pointer to the audit data
+ *
+ * This function looks up the subject/object pair in the
+ * access rule list and returns 0 if the access is permitted,
+ * non zero otherwise.
+ *
+ * Smack labels are shared on smack_list
+ */
+int smk_access(struct smack_known *subject, struct smack_known *object,
+	       int request, struct smk_audit_info *a)
+{
+	int may = MAY_NOT;
+	int rc = 0;
+
+	/*
+	 * Hardcoded comparisons.
+	 */
+	/*
+	 * A star subject can't access any object.
+	 */
+	if (subject == &smack_known_star) {
+		rc = -EACCES;
+		goto out_audit;
+	}
+	/*
+	 * An internet object can be accessed by any subject.
+	 * Tasks cannot be assigned the internet label.
+	 * An internet subject can access any object.
+	 */
+	if (object == &smack_known_web || subject == &smack_known_web)
+		goto out_audit;
+	/*
+	 * A star object can be accessed by any subject.
+	 */
+	if (object == &smack_known_star)
+		goto out_audit;
+	/*
+	 * An object can be accessed in any way by a subject
+	 * with the same label.
+	 */
+	if (subject->smk_known == object->smk_known)
+		goto out_audit;
+	/*
+	 * A hat subject can read or lock any object.
+	 * A floor object can be read or locked by any subject.
+	 */
+	if ((request & MAY_ANYREAD) == request ||
+	    (request & MAY_LOCK) == request) {
+		if (object == &smack_known_floor)
+			goto out_audit;
+		if (subject == &smack_known_hat)
+			goto out_audit;
+	}
+	/*
+	 * Beyond here an explicit relationship is required.
+	 * If the requested access is contained in the available
+	 * access (e.g. read is included in readwrite) it's
+	 * good. A negative response from smk_access_entry()
+	 * indicates there is no entry for this pair.
+	 */
+	rcu_read_lock();
+	may = smk_access_entry(subject->smk_known, object->smk_known,
+			       &subject->smk_rules);
+	rcu_read_unlock();
+
+	if (may <= 0 || (request & may) != request) {
+		rc = -EACCES;
+		goto out_audit;
+	}
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+	/*
+	 * Return a positive value if using bringup mode.
+	 * This allows the hooks to identify checks that
+	 * succeed because of "b" rules.
+	 */
+	if (may & MAY_BRINGUP)
+		rc = SMACK_BRINGUP_ALLOW;
+#endif
+
+out_audit:
+
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+	if (rc < 0) {
+		if (object == smack_unconfined)
+			rc = SMACK_UNCONFINED_OBJECT;
+		if (subject == smack_unconfined)
+			rc = SMACK_UNCONFINED_SUBJECT;
+	}
+#endif
+
+#ifdef CONFIG_AUDIT
+	if (a)
+		smack_log(subject->smk_known, object->smk_known,
+			  request, rc, a);
+#endif
+
+	return rc;
+}
+
+/**
+ * smk_tskacc - determine if a task has a specific access to an object
+ * @tsp: a pointer to the subject's task
+ * @obj_known: a pointer to the object's label entry
+ * @mode: the access requested, in "MAY" format
+ * @a : common audit data
+ *
+ * This function checks the subject task's label/object label pair
+ * in the access rule list and returns 0 if the access is permitted,
+ * non zero otherwise. It allows that the task may have the capability
+ * to override the rules.
+ */
+int smk_tskacc(struct task_smack *tsp, struct smack_known *obj_known,
+	       u32 mode, struct smk_audit_info *a)
+{
+	struct smack_known *sbj_known = smk_of_task(tsp);
+	int may;
+	int rc;
+
+	/*
+	 * Check the global rule list
+	 */
+	rc = smk_access(sbj_known, obj_known, mode, NULL);
+	if (rc >= 0) {
+		/*
+		 * If there is an entry in the task's rule list
+		 * it can further restrict access.
+		 */
+		may = smk_access_entry(sbj_known->smk_known,
+				       obj_known->smk_known,
+				       &tsp->smk_rules);
+		if (may < 0)
+			goto out_audit;
+		if ((mode & may) == mode)
+			goto out_audit;
+		rc = -EACCES;
+	}
+
+	/*
+	 * Allow for privileged to override policy.
+	 */
+	if (rc != 0 && smack_privileged(CAP_MAC_OVERRIDE))
+		rc = 0;
+
+out_audit:
+#ifdef CONFIG_AUDIT
+	if (a)
+		smack_log(sbj_known->smk_known, obj_known->smk_known,
+			  mode, rc, a);
+#endif
+	return rc;
+}
+
+/**
+ * smk_curacc - determine if current has a specific access to an object
+ * @obj_known: a pointer to the object's Smack label entry
+ * @mode: the access requested, in "MAY" format
+ * @a : common audit data
+ *
+ * This function checks the current subject label/object label pair
+ * in the access rule list and returns 0 if the access is permitted,
+ * non zero otherwise. It allows that current may have the capability
+ * to override the rules.
+ */
+int smk_curacc(struct smack_known *obj_known,
+	       u32 mode, struct smk_audit_info *a)
+{
+	struct task_smack *tsp = smack_cred(current_cred());
+
+	return smk_tskacc(tsp, obj_known, mode, a);
+}
+
+/**
+ * smack_str_from_perm : helper to translate an int to a
+ * readable string
+ * @string : the string to fill
+ * @access : the int
+ *
+ */
+int smack_str_from_perm(char *string, int access)
+{
+	int i = 0;
+
+	if (access & MAY_READ)
+		string[i++] = 'r';
+	if (access & MAY_WRITE)
+		string[i++] = 'w';
+	if (access & MAY_EXEC)
+		string[i++] = 'x';
+	if (access & MAY_APPEND)
+		string[i++] = 'a';
+	if (access & MAY_TRANSMUTE)
+		string[i++] = 't';
+	if (access & MAY_LOCK)
+		string[i++] = 'l';
+	if (access & MAY_BRINGUP)
+		string[i++] = 'b';
+	if (i == 0)
+		string[i++] = '-';
+	string[i] = '\0';
+	return i;
+}
+
+#ifdef CONFIG_AUDIT
+/**
+ * smack_log_callback - SMACK specific information
+ * will be called by generic audit code
+ * @ab : the audit_buffer
+ * @a  : audit_data
+ *
+ */
+static void smack_log_callback(struct audit_buffer *ab, void *a)
+{
+	struct common_audit_data *ad = a;
+	struct smack_audit_data *sad = ad->smack_audit_data;
+	audit_log_format(ab, "lsm=SMACK fn=%s action=%s",
+			 ad->smack_audit_data->function,
+			 sad->result ? "denied" : "granted");
+	audit_log_format(ab, " subject=");
+	audit_log_untrustedstring(ab, sad->subject);
+	audit_log_format(ab, " object=");
+	audit_log_untrustedstring(ab, sad->object);
+	if (sad->request[0] == '\0')
+		audit_log_format(ab, " labels_differ");
+	else
+		audit_log_format(ab, " requested=%s", sad->request);
+}
+
+/**
+ *  smack_log - Audit the granting or denial of permissions.
+ *  @subject_label : smack label of the requester
+ *  @object_label  : smack label of the object being accessed
+ *  @request: requested permissions
+ *  @result: result from smk_access
+ *  @ad:  auxiliary audit data
+ *
+ * Audit the granting or denial of permissions in accordance
+ * with the policy.
+ */
+void smack_log(char *subject_label, char *object_label, int request,
+	       int result, struct smk_audit_info *ad)
+{
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+	char request_buffer[SMK_NUM_ACCESS_TYPE + 5];
+#else
+	char request_buffer[SMK_NUM_ACCESS_TYPE + 1];
+#endif
+	struct smack_audit_data *sad;
+	struct common_audit_data *a = &ad->a;
+
+	/* check if we have to log the current event */
+	if (result < 0 && (log_policy & SMACK_AUDIT_DENIED) == 0)
+		return;
+	if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0)
+		return;
+
+	sad = a->smack_audit_data;
+
+	if (sad->function == NULL)
+		sad->function = "unknown";
+
+	/* end preparing the audit data */
+	smack_str_from_perm(request_buffer, request);
+	sad->subject = subject_label;
+	sad->object  = object_label;
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+	/*
+	 * The result may be positive in bringup mode.
+	 * A positive result is an allow, but not for normal reasons.
+	 * Mark it as successful, but don't filter it out even if
+	 * the logging policy says to do so.
+	 */
+	if (result == SMACK_UNCONFINED_SUBJECT)
+		strcat(request_buffer, "(US)");
+	else if (result == SMACK_UNCONFINED_OBJECT)
+		strcat(request_buffer, "(UO)");
+
+	if (result > 0)
+		result = 0;
+#endif
+	sad->request = request_buffer;
+	sad->result  = result;
+
+	common_lsm_audit(a, smack_log_callback, NULL);
+}
+#else /* #ifdef CONFIG_AUDIT */
+void smack_log(char *subject_label, char *object_label, int request,
+	       int result, struct smk_audit_info *ad)
+{
+}
+#endif
+
+DEFINE_MUTEX(smack_known_lock);
+
+struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
+
+/**
+ * smk_insert_entry - insert a smack label into a hash map,
+ * @skp: smack label
+ *
+ * this function must be called under smack_known_lock
+ */
+void smk_insert_entry(struct smack_known *skp)
+{
+	unsigned int hash;
+	struct hlist_head *head;
+
+	hash = full_name_hash(NULL, skp->smk_known, strlen(skp->smk_known));
+	head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
+
+	hlist_add_head_rcu(&skp->smk_hashed, head);
+	list_add_rcu(&skp->list, &smack_known_list);
+}
+
+/**
+ * smk_find_entry - find a label on the list, return the list entry
+ * @string: a text string that might be a Smack label
+ *
+ * Returns a pointer to the entry in the label list that
+ * matches the passed string or NULL if not found.
+ */
+struct smack_known *smk_find_entry(const char *string)
+{
+	unsigned int hash;
+	struct hlist_head *head;
+	struct smack_known *skp;
+
+	hash = full_name_hash(NULL, string, strlen(string));
+	head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
+
+	hlist_for_each_entry_rcu(skp, head, smk_hashed)
+		if (strcmp(skp->smk_known, string) == 0)
+			return skp;
+
+	return NULL;
+}
+
+/**
+ * smk_parse_label_len - calculate the length of the starting segment
+ *                       in the string that constitutes a valid smack label
+ * @string: a text string that might contain a Smack label at the beginning
+ * @len: the maximum size to look into, may be zero if string is null-terminated
+ *
+ * Returns the length of the segment (0 < L < SMK_LONGLABEL) or an error code.
+ */
+int smk_parse_label_len(const char *string, int len)
+{
+	int i;
+
+	if (len <= 0 || len > SMK_LONGLABEL)
+		len = SMK_LONGLABEL;
+
+	/*
+	 * Reserve a leading '-' as an indicator that
+	 * this isn't a label, but an option to interfaces
+	 * including /smack/cipso and /smack/cipso2
+	 */
+	if (string[0] == '-')
+		return -EINVAL;
+
+	for (i = 0; i < len; i++)
+		if (string[i] > '~' || string[i] <= ' ' || string[i] == '/' ||
+		    string[i] == '"' || string[i] == '\\' || string[i] == '\'')
+			break;
+
+	if (i == 0 || i >= SMK_LONGLABEL)
+		return -EINVAL;
+
+	return i;
+}
+
+/**
+ * smk_parse_smack - copy the starting segment in the string
+ *                   that constitutes a valid smack label
+ * @string: a text string that might contain a Smack label at the beginning
+ * @len: the maximum size to look into, may be zero if string is null-terminated
+ *
+ * Returns a pointer to the copy of the label or an error code.
+ */
+char *smk_parse_smack(const char *string, int len)
+{
+	char *smack;
+	int i = smk_parse_label_len(string, len);
+
+	if (i < 0)
+		return ERR_PTR(-EINVAL);
+
+	smack = kstrndup(string, i, GFP_NOFS);
+	if (!smack)
+		return ERR_PTR(-ENOMEM);
+	return smack;
+}
+
+/**
+ * smk_netlbl_mls - convert a catset to netlabel mls categories
+ * @level: MLS sensitivity level
+ * @catset: the Smack categories
+ * @sap: where to put the netlabel categories
+ * @len: number of bytes for the levels in a CIPSO IP option
+ *
+ * Allocates and fills attr.mls
+ * Returns 0 on success, error code on failure.
+ */
+int smk_netlbl_mls(int level, char *catset, struct netlbl_lsm_secattr *sap,
+			int len)
+{
+	unsigned char *cp;
+	unsigned char m;
+	int cat;
+	int rc;
+	int byte;
+
+	sap->flags |= NETLBL_SECATTR_MLS_CAT;
+	sap->attr.mls.lvl = level;
+	sap->attr.mls.cat = NULL;
+
+	for (cat = 1, cp = catset, byte = 0; byte < len; cp++, byte++)
+		for (m = 0x80; m != 0; m >>= 1, cat++) {
+			if ((m & *cp) == 0)
+				continue;
+			rc = netlbl_catmap_setbit(&sap->attr.mls.cat,
+						  cat, GFP_NOFS);
+			if (rc < 0) {
+				netlbl_catmap_free(sap->attr.mls.cat);
+				return rc;
+			}
+		}
+
+	return 0;
+}
+
+/**
+ * smack_populate_secattr - fill in the smack_known netlabel information
+ * @skp: pointer to the structure to fill
+ *
+ * Populate the netlabel secattr structure for a Smack label.
+ *
+ * Returns 0 unless creating the category mapping fails
+ */
+int smack_populate_secattr(struct smack_known *skp)
+{
+	int slen;
+
+	skp->smk_netlabel.attr.secid = skp->smk_secid;
+	skp->smk_netlabel.domain = skp->smk_known;
+	skp->smk_netlabel.cache = netlbl_secattr_cache_alloc(GFP_ATOMIC);
+	if (skp->smk_netlabel.cache != NULL) {
+		skp->smk_netlabel.flags |= NETLBL_SECATTR_CACHE;
+		skp->smk_netlabel.cache->free = NULL;
+		skp->smk_netlabel.cache->data = skp;
+	}
+	skp->smk_netlabel.flags |= NETLBL_SECATTR_SECID |
+				   NETLBL_SECATTR_MLS_LVL |
+				   NETLBL_SECATTR_DOMAIN;
+	/*
+	 * If direct labeling works use it.
+	 * Otherwise use mapped labeling.
+	 */
+	slen = strlen(skp->smk_known);
+	if (slen < SMK_CIPSOLEN)
+		return smk_netlbl_mls(smack_cipso_direct, skp->smk_known,
+				      &skp->smk_netlabel, slen);
+
+	return smk_netlbl_mls(smack_cipso_mapped, (char *)&skp->smk_secid,
+			      &skp->smk_netlabel, sizeof(skp->smk_secid));
+}
+
+/**
+ * smk_import_valid_allocated_label - import a label, return the list entry
+ * @smack: a text string that is a valid Smack label and may be kfree()ed.
+ *         It is consumed: either becomes a part of the entry or kfree'ed.
+ * @gfp: Allocation type
+ *
+ * Returns: see description of smk_import_entry()
+ */
+static struct smack_known *
+smk_import_allocated_label(char *smack, gfp_t gfp)
+{
+	struct smack_known *skp;
+	int rc;
+
+	mutex_lock(&smack_known_lock);
+
+	skp = smk_find_entry(smack);
+	if (skp != NULL)
+		goto freeout;
+
+	skp = kzalloc_obj(*skp, gfp);
+	if (skp == NULL) {
+		skp = ERR_PTR(-ENOMEM);
+		goto freeout;
+	}
+
+	skp->smk_known = smack;
+	skp->smk_secid = smack_next_secid++;
+
+	rc = smack_populate_secattr(skp);
+	if (rc >= 0) {
+		INIT_LIST_HEAD(&skp->smk_rules);
+		mutex_init(&skp->smk_rules_lock);
+		/*
+		 * Make sure that the entry is actually
+		 * filled before putting it on the list.
+		 */
+		smk_insert_entry(skp);
+		goto unlockout;
+	}
+	kfree(skp);
+	skp = ERR_PTR(rc);
+freeout:
+	kfree(smack);
+unlockout:
+	mutex_unlock(&smack_known_lock);
+
+	return skp;
+}
+
+/**
+ * smk_import_entry - import a label, return the list entry
+ * @string: a text string that might contain a Smack label at the beginning
+ * @len: the maximum size to look into, may be zero if string is null-terminated
+ *
+ * Returns a pointer to the entry in the label list that
+ * matches the passed string, adding it if necessary,
+ * or an error code.
+ */
+struct smack_known *smk_import_entry(const char *string, int len)
+{
+	char *smack = smk_parse_smack(string, len);
+
+	if (IS_ERR(smack))
+		return ERR_CAST(smack);
+
+	return smk_import_allocated_label(smack, GFP_NOFS);
+}
+
+/**
+ * smk_import_valid_label - import a label, return the list entry
+ * @label: a text string that is a valid Smack label, not null-terminated
+ * @label_len: the length of the text string in the @label
+ * @gfp: the GFP mask used for allocating memory for the @label text string copy
+ *
+ * Return: see description of smk_import_entry()
+ */
+struct smack_known *
+smk_import_valid_label(const char *label, int label_len, gfp_t gfp)
+{
+	char *smack = kstrndup(label, label_len, gfp);
+
+	if  (!smack)
+		return ERR_PTR(-ENOMEM);
+
+	return smk_import_allocated_label(smack, gfp);
+}
+
+/**
+ * smack_from_secid - find the Smack label associated with a secid
+ * @secid: an integer that might be associated with a Smack label
+ *
+ * Returns a pointer to the appropriate Smack label entry if there is one,
+ * otherwise a pointer to the invalid Smack label.
+ */
+struct smack_known *smack_from_secid(const u32 secid)
+{
+	struct smack_known *skp;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(skp, &smack_known_list, list) {
+		if (skp->smk_secid == secid) {
+			rcu_read_unlock();
+			return skp;
+		}
+	}
+
+	/*
+	 * If we got this far someone asked for the translation
+	 * of a secid that is not on the list.
+	 */
+	rcu_read_unlock();
+	return &smack_known_huh;
+}
+
+/*
+ * Unless a process is running with one of these labels
+ * even having CAP_MAC_OVERRIDE isn't enough to grant
+ * privilege to violate MAC policy. If no labels are
+ * designated (the empty list case) capabilities apply to
+ * everyone.
+ */
+LIST_HEAD(smack_onlycap_list);
+DEFINE_MUTEX(smack_onlycap_lock);
+
+/**
+ * smack_privileged_cred - are all privilege requirements met by cred
+ * @cap: The requested capability
+ * @cred: the credential to use
+ *
+ * Is the task privileged and allowed to be privileged
+ * by the onlycap rule.
+ *
+ * Returns true if the task is allowed to be privileged, false if it's not.
+ */
+bool smack_privileged_cred(int cap, const struct cred *cred)
+{
+	struct task_smack *tsp = smack_cred(cred);
+	struct smack_known *skp = tsp->smk_task;
+	struct smack_known_list_elem *sklep;
+	int rc;
+
+	rc = cap_capable(cred, &init_user_ns, cap, CAP_OPT_NONE);
+	if (rc)
+		return false;
+
+	rcu_read_lock();
+	if (list_empty(&smack_onlycap_list)) {
+		rcu_read_unlock();
+		return true;
+	}
+
+	list_for_each_entry_rcu(sklep, &smack_onlycap_list, list) {
+		if (sklep->smk_label == skp) {
+			rcu_read_unlock();
+			return true;
+		}
+	}
+	rcu_read_unlock();
+
+	return false;
+}
+
+/**
+ * smack_privileged - are all privilege requirements met
+ * @cap: The requested capability
+ *
+ * Is the task privileged and allowed to be privileged
+ * by the onlycap rule.
+ *
+ * Returns true if the task is allowed to be privileged, false if it's not.
+ */
+bool smack_privileged(int cap)
+{
+	/*
+	 * All kernel tasks are privileged
+	 */
+	if (unlikely(current->flags & PF_KTHREAD))
+		return true;
+
+	return smack_privileged_cred(cap, current_cred());
+}

linux-7.2.3/security/smack/smack_netfilter.c

@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Simplified MAC Kernel (smack) security module
+ *
+ *  This file contains the Smack netfilter implementation
+ *
+ *  Author:
+ *	Casey Schaufler <casey@schaufler-ca.com>
+ *
+ *  Copyright (C) 2014 Casey Schaufler <casey@schaufler-ca.com>
+ *  Copyright (C) 2014 Intel Corporation.
+ */
+
+#include <linux/netfilter_ipv4.h>
+#include <linux/netfilter_ipv6.h>
+#include <linux/netdevice.h>
+#include <net/inet_sock.h>
+#include <net/net_namespace.h>
+#include "smack.h"
+
+static unsigned int smack_ip_output(void *priv,
+				    struct sk_buff *skb,
+				    const struct nf_hook_state *state)
+{
+	struct sock *sk = skb_to_full_sk(skb);
+	struct socket_smack *ssp;
+	struct smack_known *skp;
+
+	if (sk) {
+		ssp = smack_sock(sk);
+		skp = ssp->smk_out;
+		skb->secmark = skp->smk_secid;
+	}
+
+	return NF_ACCEPT;
+}
+
+static const struct nf_hook_ops smack_nf_ops[] = {
+	{
+		.hook =		smack_ip_output,
+		.pf =		NFPROTO_IPV4,
+		.hooknum =	NF_INET_LOCAL_OUT,
+		.priority =	NF_IP_PRI_SELINUX_FIRST,
+	},
+#if IS_ENABLED(CONFIG_IPV6)
+	{
+		.hook =		smack_ip_output,
+		.pf =		NFPROTO_IPV6,
+		.hooknum =	NF_INET_LOCAL_OUT,
+		.priority =	NF_IP6_PRI_SELINUX_FIRST,
+	},
+#endif	/* IPV6 */
+};
+
+static int __net_init smack_nf_register(struct net *net)
+{
+	return nf_register_net_hooks(net, smack_nf_ops,
+				     ARRAY_SIZE(smack_nf_ops));
+}
+
+static void __net_exit smack_nf_unregister(struct net *net)
+{
+	nf_unregister_net_hooks(net, smack_nf_ops, ARRAY_SIZE(smack_nf_ops));
+}
+
+static struct pernet_operations smack_net_ops = {
+	.init = smack_nf_register,
+	.exit = smack_nf_unregister,
+};
+
+int __init smack_nf_ip_init(void)
+{
+	if (smack_enabled == 0)
+		return 0;
+
+	printk(KERN_DEBUG "Smack: Registering netfilter hooks\n");
+	return register_pernet_subsys(&smack_net_ops);
+}