Resguardo inicial

linux-7.2.3/tools/testing/selftests/exec/.gitignore

@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: GPL-2.0-only
+subdir*
+script*
+execveat
+execveat.symlink
+execveat.moved
+execveat.path.ephemeral
+execveat.ephemeral
+execveat.denatured
+non-regular
+null-argv
+/check-exec
+/false
+/inc
+/load_address.*
+!load_address.c
+/recursion-depth
+/set-exec
+xxxxxxxx*
+pipe
+S_I*.test

linux-7.2.3/tools/testing/selftests/exec/Makefile

@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: GPL-2.0
+CFLAGS = -Wall
+CFLAGS += -Wno-nonnull
+CFLAGS += $(KHDR_INCLUDES)
+
+LDLIBS += -lcap
+
+ALIGNS := 0x1000 0x200000 0x1000000
+ALIGN_PIES        := $(patsubst %,load_address.%,$(ALIGNS))
+ALIGN_STATIC_PIES := $(patsubst %,load_address.static.%,$(ALIGNS))
+ALIGNMENT_TESTS   := $(ALIGN_PIES) $(ALIGN_STATIC_PIES)
+
+TEST_PROGS := binfmt_script.py check-exec-tests.sh
+TEST_GEN_PROGS := execveat non-regular $(ALIGNMENT_TESTS)
+TEST_GEN_PROGS_EXTENDED := false inc set-exec script-exec.inc script-noexec.inc
+TEST_GEN_FILES := execveat.symlink execveat.denatured script subdir
+# Makefile is a run-time dependency, since it's accessed by the execveat test
+TEST_FILES := Makefile
+
+TEST_GEN_PROGS += recursion-depth
+TEST_GEN_PROGS += null-argv
+TEST_GEN_PROGS += check-exec
+
+EXTRA_CLEAN := $(OUTPUT)/subdir.moved $(OUTPUT)/execveat.moved $(OUTPUT)/xxxxx*	\
+	       $(OUTPUT)/S_I*.test
+
+include ../lib.mk
+
+CHECK_EXEC_SAMPLES := $(top_srcdir)/samples/check-exec
+
+$(OUTPUT)/subdir:
+	mkdir -p $@
+$(OUTPUT)/script: Makefile
+	echo '#!/bin/bash' > $@
+	echo 'exit $$*' >> $@
+	chmod +x $@
+$(OUTPUT)/execveat.symlink: $(OUTPUT)/execveat
+	cd $(OUTPUT) && ln -s -f $(shell basename $<) $(shell basename $@)
+$(OUTPUT)/execveat.denatured: $(OUTPUT)/execveat
+	cp $< $@
+	chmod -x $@
+$(OUTPUT)/load_address.0x%: load_address.c
+	$(CC) $(CFLAGS) $(LDFLAGS) -Wl,-z,max-page-size=$(lastword $(subst ., ,$@)) \
+		-fPIE -pie $< -o $@
+$(OUTPUT)/load_address.static.0x%: load_address.c
+	$(CC) $(CFLAGS) $(LDFLAGS) -Wl,-z,max-page-size=$(lastword $(subst ., ,$@)) \
+		-fPIE -static-pie $< -o $@
+$(OUTPUT)/false: false.c
+	$(CC) $(CFLAGS) $(LDFLAGS) -static $< -o $@
+$(OUTPUT)/inc: $(CHECK_EXEC_SAMPLES)/inc.c
+	$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
+$(OUTPUT)/set-exec: $(CHECK_EXEC_SAMPLES)/set-exec.c
+	$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
+$(OUTPUT)/script-exec.inc: $(CHECK_EXEC_SAMPLES)/script-exec.inc
+	cp $< $@
+$(OUTPUT)/script-noexec.inc: $(CHECK_EXEC_SAMPLES)/script-noexec.inc
+	cp $< $@

linux-7.2.3/tools/testing/selftests/exec/binfmt_script.py

@@ -0,0 +1,179 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+#
+# Test that truncation of bprm->buf doesn't cause unexpected execs paths, along
+# with various other pathological cases.
+import os, subprocess
+
+# Relevant commits
+#
+# b5372fe5dc84 ("exec: load_script: Do not exec truncated interpreter path")
+# 6eb3c3d0a52d ("exec: increase BINPRM_BUF_SIZE to 256")
+
+# BINPRM_BUF_SIZE
+SIZE=256
+
+NAME_MAX=int(subprocess.check_output(["getconf", "NAME_MAX", "."]))
+
+test_num=0
+pass_num=0
+fail_num=0
+
+code='''#!/usr/bin/perl
+print "Executed interpreter! Args:\n";
+print "0 : '$0'\n";
+$counter = 1;
+foreach my $a (@ARGV) {
+    print "$counter : '$a'\n";
+    $counter++;
+}
+'''
+
+##
+# test - produce a binfmt_script hashbang line for testing
+#
+# @size:     bytes for bprm->buf line, including hashbang but not newline
+# @good:     whether this script is expected to execute correctly
+# @hashbang: the special 2 bytes for running binfmt_script
+# @leading:  any leading whitespace before the executable path
+# @root:     start of executable pathname
+# @target:   end of executable pathname
+# @arg:      bytes following the executable pathname
+# @fill:     character to fill between @root and @target to reach @size bytes
+# @newline:  character to use as newline, not counted towards @size
+# ...
+def test(name, size, good=True, leading="", root="./", target="/perl",
+                     fill="A", arg="", newline="\n", hashbang="#!"):
+    global test_num, pass_num, fail_num, tests, NAME_MAX
+    test_num += 1
+    if test_num > tests:
+        raise ValueError("more binfmt_script tests than expected! (want %d, expected %d)"
+                         % (test_num, tests))
+
+    middle = ""
+    remaining = size - len(hashbang) - len(leading) - len(root) - len(target) - len(arg)
+    # The middle of the pathname must not exceed NAME_MAX
+    while remaining >= NAME_MAX:
+        middle += fill * (NAME_MAX - 1)
+        middle += '/'
+        remaining -= NAME_MAX
+    middle += fill * remaining
+
+    dirpath = root + middle
+    binary = dirpath + target
+    if len(target):
+        os.makedirs(dirpath, mode=0o755, exist_ok=True)
+        open(binary, "w").write(code)
+        os.chmod(binary, 0o755)
+
+    buf=hashbang + leading + root + middle + target + arg + newline
+    if len(newline) > 0:
+        buf += 'echo this is not really perl\n'
+
+    script = "binfmt_script-%s" % (name)
+    open(script, "w").write(buf)
+    os.chmod(script, 0o755)
+
+    proc = subprocess.Popen(["./%s" % (script)], shell=True,
+                            stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+    stdout = proc.communicate()[0]
+
+    if proc.returncode == 0 and b'Executed interpreter' in stdout:
+        if good:
+            print("ok %d - binfmt_script %s (successful good exec)"
+                  % (test_num, name))
+            pass_num += 1
+        else:
+            print("not ok %d - binfmt_script %s succeeded when it should have failed"
+                  % (test_num, name))
+            fail_num = 1
+    else:
+        if good:
+            print("not ok %d - binfmt_script %s failed when it should have succeeded (rc:%d)"
+                  % (test_num, name, proc.returncode))
+            fail_num = 1
+        else:
+            print("ok %d - binfmt_script %s (correctly failed bad exec)"
+                  % (test_num, name))
+            pass_num += 1
+
+    # Clean up crazy binaries
+    os.unlink(script)
+    if len(target):
+        elements = binary.split('/')
+        os.unlink(binary)
+        elements.pop()
+        while len(elements) > 1:
+            os.rmdir("/".join(elements))
+            elements.pop()
+
+tests=27
+print("TAP version 1.3")
+print("1..%d" % (tests))
+
+### FAIL (8 tests)
+
+# Entire path is well past the BINFMT_BUF_SIZE.
+test(name="too-big",        size=SIZE+80, good=False)
+# Path is right at max size, making it impossible to tell if it was truncated.
+test(name="exact",          size=SIZE,    good=False)
+# Same as above, but with leading whitespace.
+test(name="exact-space",    size=SIZE,    good=False, leading=" ")
+# Huge buffer of only whitespace.
+test(name="whitespace-too-big", size=SIZE+71, good=False, root="",
+                                              fill=" ", target="")
+# A good path, but it gets truncated due to leading whitespace.
+test(name="truncated",      size=SIZE+17, good=False, leading=" " * 19)
+# Entirely empty except for #!
+test(name="empty",          size=2,       good=False, root="",
+                                          fill="", target="", newline="")
+# Within size, but entirely spaces
+test(name="spaces",         size=SIZE-1,  good=False, root="", fill=" ",
+                                          target="", newline="")
+# Newline before binary.
+test(name="newline-prefix", size=SIZE-1,  good=False, leading="\n",
+                                          root="", fill=" ", target="")
+
+### ok (19 tests)
+
+# The original test case that was broken by commit:
+# 8099b047ecc4 ("exec: load_script: don't blindly truncate shebang string")
+test(name="test.pl",        size=439, leading=" ",
+     root="./nix/store/bwav8kz8b3y471wjsybgzw84mrh4js9-perl-5.28.1/bin",
+     arg=" -I/nix/store/x6yyav38jgr924nkna62q3pkp0dgmzlx-perl5.28.1-File-Slurp-9999.25/lib/perl5/site_perl -I/nix/store/ha8v67sl8dac92r9z07vzr4gv1y9nwqz-perl5.28.1-Net-DBus-1.1.0/lib/perl5/site_perl -I/nix/store/dcrkvnjmwh69ljsvpbdjjdnqgwx90a9d-perl5.28.1-XML-Parser-2.44/lib/perl5/site_perl -I/nix/store/rmji88k2zz7h4zg97385bygcydrf2q8h-perl5.28.1-XML-Twig-3.52/lib/perl5/site_perl")
+# One byte under size, leaving newline visible.
+test(name="one-under",           size=SIZE-1)
+# Two bytes under size, leaving newline visible.
+test(name="two-under",           size=SIZE-2)
+# Exact size, but trailing whitespace visible instead of newline
+test(name="exact-trunc-whitespace", size=SIZE, arg=" ")
+# Exact size, but trailing space and first arg char visible instead of newline.
+test(name="exact-trunc-arg",     size=SIZE, arg=" f")
+# One bute under, with confirmed non-truncated arg since newline now visible.
+test(name="one-under-full-arg",  size=SIZE-1, arg=" f")
+# Short read buffer by one byte.
+test(name="one-under-no-nl",     size=SIZE-1, newline="")
+# Short read buffer by half buffer size.
+test(name="half-under-no-nl",    size=int(SIZE/2), newline="")
+# One byte under with whitespace arg. leaving wenline visible.
+test(name="one-under-trunc-arg", size=SIZE-1, arg=" ")
+# One byte under with whitespace leading. leaving wenline visible.
+test(name="one-under-leading",   size=SIZE-1, leading=" ")
+# One byte under with whitespace leading and as arg. leaving newline visible.
+test(name="one-under-leading-trunc-arg",  size=SIZE-1, leading=" ", arg=" ")
+# Same as above, but with 2 bytes under
+test(name="two-under-no-nl",     size=SIZE-2, newline="")
+test(name="two-under-trunc-arg", size=SIZE-2, arg=" ")
+test(name="two-under-leading",   size=SIZE-2, leading=" ")
+test(name="two-under-leading-trunc-arg",   size=SIZE-2, leading=" ", arg=" ")
+# Same as above, but with buffer half filled
+test(name="two-under-no-nl",     size=int(SIZE/2), newline="")
+test(name="two-under-trunc-arg", size=int(SIZE/2), arg=" ")
+test(name="two-under-leading",   size=int(SIZE/2), leading=" ")
+test(name="two-under-lead-trunc-arg", size=int(SIZE/2), leading=" ", arg=" ")
+
+print("# Totals: pass:%d fail:%d xfail:0 xpass:0 skip:0 error:0" % (pass_num, fail_num))
+
+if test_num != tests:
+    raise ValueError("fewer binfmt_script tests than expected! (ran %d, expected %d"
+                     % (test_num, tests))

linux-7.2.3/tools/testing/selftests/exec/check-exec-tests.sh

@@ -0,0 +1,205 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Test the "inc" interpreter.
+#
+# See include/uapi/linux/securebits.h, include/uapi/linux/fcntl.h and
+# samples/check-exec/inc.c
+#
+# Copyright © 2024 Microsoft Corporation
+
+set -u -e -o pipefail
+
+EXPECTED_OUTPUT="1"
+exec 2>/dev/null
+
+DIR="$(dirname $(readlink -f "$0"))"
+source "${DIR}"/../kselftest/ktap_helpers.sh
+
+exec_direct() {
+	local expect="$1"
+	local script="$2"
+	shift 2
+	local ret=0
+	local out
+
+	# Updates PATH for `env` to execute the `inc` interpreter.
+	out="$(PATH="." "$@" "${script}")" || ret=$?
+
+	if [[ ${ret} -ne ${expect} ]]; then
+		echo "ERROR: Wrong expectation for direct file execution: ${ret}"
+		return 1
+	fi
+	if [[ ${ret} -eq 0 && "${out}" != "${EXPECTED_OUTPUT}" ]]; then
+		echo "ERROR: Wrong output for direct file execution: ${out}"
+		return 1
+	fi
+}
+
+exec_indirect() {
+	local expect="$1"
+	local script="$2"
+	shift 2
+	local ret=0
+	local out
+
+	# Script passed as argument.
+	out="$("$@" ./inc "${script}")" || ret=$?
+
+	if [[ ${ret} -ne ${expect} ]]; then
+		echo "ERROR: Wrong expectation for indirect file execution: ${ret}"
+		return 1
+	fi
+	if [[ ${ret} -eq 0 && "${out}" != "${EXPECTED_OUTPUT}" ]]; then
+		echo "ERROR: Wrong output for indirect file execution: ${out}"
+		return 1
+	fi
+}
+
+exec_stdin_reg() {
+	local expect="$1"
+	local script="$2"
+	shift 2
+	local ret=0
+	local out
+
+	# Executing stdin must be allowed if the related file is executable.
+	out="$("$@" ./inc -i < "${script}")" || ret=$?
+
+	if [[ ${ret} -ne ${expect} ]]; then
+		echo "ERROR: Wrong expectation for stdin regular file execution: ${ret}"
+		return 1
+	fi
+	if [[ ${ret} -eq 0 && "${out}" != "${EXPECTED_OUTPUT}" ]]; then
+		echo "ERROR: Wrong output for stdin regular file execution: ${out}"
+		return 1
+	fi
+}
+
+exec_stdin_pipe() {
+	local expect="$1"
+	shift
+	local ret=0
+	local out
+
+	# A pipe is not executable.
+	out="$(cat script-exec.inc | "$@" ./inc -i)" || ret=$?
+
+	if [[ ${ret} -ne ${expect} ]]; then
+		echo "ERROR: Wrong expectation for stdin pipe execution: ${ret}"
+		return 1
+	fi
+}
+
+exec_argument() {
+	local expect="$1"
+	local ret=0
+	shift
+	local out
+
+	# Script not coming from a file must not be executed.
+	out="$("$@" ./inc -c "$(< script-exec.inc)")" || ret=$?
+
+	if [[ ${ret} -ne ${expect} ]]; then
+		echo "ERROR: Wrong expectation for arbitrary argument execution: ${ret}"
+		return 1
+	fi
+	if [[ ${ret} -eq 0 && "${out}" != "${EXPECTED_OUTPUT}" ]]; then
+		echo "ERROR: Wrong output for arbitrary argument execution: ${out}"
+		return 1
+	fi
+}
+
+exec_interactive() {
+	exec_stdin_pipe "$@"
+	exec_argument "$@"
+}
+
+ktap_test() {
+	ktap_test_result "$*" "$@"
+}
+
+ktap_print_header
+ktap_set_plan 28
+
+# Without secbit configuration, nothing is changed.
+
+ktap_print_msg "By default, executable scripts are allowed to be interpreted and executed."
+ktap_test exec_direct 0 script-exec.inc
+ktap_test exec_indirect 0 script-exec.inc
+
+ktap_print_msg "By default, executable stdin is allowed to be interpreted."
+ktap_test exec_stdin_reg 0 script-exec.inc
+
+ktap_print_msg "By default, non-executable scripts are allowed to be interpreted, but not directly executed."
+# We get 126 because of direct execution by Bash.
+ktap_test exec_direct 126 script-noexec.inc
+ktap_test exec_indirect 0 script-noexec.inc
+
+ktap_print_msg "By default, non-executable stdin is allowed to be interpreted."
+ktap_test exec_stdin_reg 0 script-noexec.inc
+
+ktap_print_msg "By default, interactive commands are allowed to be interpreted."
+ktap_test exec_interactive 0
+
+# With only file restriction: protect non-malicious users from inadvertent errors (e.g. python ~/Downloads/*.py).
+
+ktap_print_msg "With -f, executable scripts are allowed to be interpreted and executed."
+ktap_test exec_direct 0 script-exec.inc ./set-exec -f --
+ktap_test exec_indirect 0 script-exec.inc ./set-exec -f --
+
+ktap_print_msg "With -f, executable stdin is allowed to be interpreted."
+ktap_test exec_stdin_reg 0 script-exec.inc ./set-exec -f --
+
+ktap_print_msg "With -f, non-executable scripts are not allowed to be executed nor interpreted."
+# Direct execution of non-executable script is alwayse denied by the kernel.
+ktap_test exec_direct 1 script-noexec.inc ./set-exec -f --
+ktap_test exec_indirect 1 script-noexec.inc ./set-exec -f --
+
+ktap_print_msg "With -f, non-executable stdin is allowed to be interpreted."
+ktap_test exec_stdin_reg 0 script-noexec.inc ./set-exec -f --
+
+ktap_print_msg "With -f, interactive commands are allowed to be interpreted."
+ktap_test exec_interactive 0 ./set-exec -f --
+
+# With only denied interactive commands: check or monitor script content (e.g. with LSM).
+
+ktap_print_msg "With -i, executable scripts are allowed to be interpreted and executed."
+ktap_test exec_direct 0 script-exec.inc ./set-exec -i --
+ktap_test exec_indirect 0 script-exec.inc ./set-exec -i --
+
+ktap_print_msg "With -i, executable stdin is allowed to be interpreted."
+ktap_test exec_stdin_reg 0 script-exec.inc ./set-exec -i --
+
+ktap_print_msg "With -i, non-executable scripts are allowed to be interpreted, but not directly executed."
+# Direct execution of non-executable script is alwayse denied by the kernel.
+ktap_test exec_direct 1 script-noexec.inc ./set-exec -i --
+ktap_test exec_indirect 0 script-noexec.inc ./set-exec -i --
+
+ktap_print_msg "With -i, non-executable stdin is not allowed to be interpreted."
+ktap_test exec_stdin_reg 1 script-noexec.inc ./set-exec -i --
+
+ktap_print_msg "With -i, interactive commands are not allowed to be interpreted."
+ktap_test exec_interactive 1 ./set-exec -i --
+
+# With both file restriction and denied interactive commands: only allow executable scripts.
+
+ktap_print_msg "With -fi, executable scripts are allowed to be interpreted and executed."
+ktap_test exec_direct 0 script-exec.inc ./set-exec -fi --
+ktap_test exec_indirect 0 script-exec.inc ./set-exec -fi --
+
+ktap_print_msg "With -fi, executable stdin is allowed to be interpreted."
+ktap_test exec_stdin_reg 0 script-exec.inc ./set-exec -fi --
+
+ktap_print_msg "With -fi, non-executable scripts are not allowed to be interpreted nor executed."
+# Direct execution of non-executable script is alwayse denied by the kernel.
+ktap_test exec_direct 1 script-noexec.inc ./set-exec -fi --
+ktap_test exec_indirect 1 script-noexec.inc ./set-exec -fi --
+
+ktap_print_msg "With -fi, non-executable stdin is not allowed to be interpreted."
+ktap_test exec_stdin_reg 1 script-noexec.inc ./set-exec -fi --
+
+ktap_print_msg "With -fi, interactive commands are not allowed to be interpreted."
+ktap_test exec_interactive 1 ./set-exec -fi --
+
+ktap_finished

linux-7.2.3/tools/testing/selftests/exec/check-exec.c

@@ -0,0 +1,463 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Test execveat(2) with AT_EXECVE_CHECK, and prctl(2) with
+ * SECBIT_EXEC_RESTRICT_FILE, SECBIT_EXEC_DENY_INTERACTIVE, and their locked
+ * counterparts.
+ *
+ * Copyright © 2018-2020 ANSSI
+ * Copyright © 2024 Microsoft Corporation
+ *
+ * Author: Mickaël Salaün <mic@digikod.net>
+ */
+
+#include <asm-generic/unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/prctl.h>
+#include <linux/securebits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/capability.h>
+#include <sys/mount.h>
+#include <sys/prctl.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/sysmacros.h>
+#include <unistd.h>
+
+/* Defines AT_EXECVE_CHECK without type conflicts. */
+#define _ASM_GENERIC_FCNTL_H
+#include <linux/fcntl.h>
+
+#include "kselftest_harness.h"
+
+static int sys_execveat(int dirfd, const char *pathname, char *const argv[],
+			char *const envp[], int flags)
+{
+	return syscall(__NR_execveat, dirfd, pathname, argv, envp, flags);
+}
+
+static void drop_privileges(struct __test_metadata *const _metadata)
+{
+	const unsigned int noroot = SECBIT_NOROOT | SECBIT_NOROOT_LOCKED;
+	cap_t cap_p;
+
+	if ((cap_get_secbits() & noroot) != noroot)
+		EXPECT_EQ(0, cap_set_secbits(noroot));
+
+	cap_p = cap_get_proc();
+	EXPECT_NE(NULL, cap_p);
+	EXPECT_NE(-1, cap_clear(cap_p));
+
+	/*
+	 * Drops everything, especially CAP_SETPCAP, CAP_DAC_OVERRIDE, and
+	 * CAP_DAC_READ_SEARCH.
+	 */
+	EXPECT_NE(-1, cap_set_proc(cap_p));
+	EXPECT_NE(-1, cap_free(cap_p));
+}
+
+static int test_secbits_set(const unsigned int secbits)
+{
+	int err;
+
+	err = prctl(PR_SET_SECUREBITS, secbits);
+	if (err)
+		return errno;
+	return 0;
+}
+
+FIXTURE(access)
+{
+	int memfd, pipefd;
+	int pipe_fds[2], socket_fds[2];
+};
+
+FIXTURE_VARIANT(access)
+{
+	const bool mount_exec;
+	const bool file_exec;
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(access, mount_exec_file_exec) {
+	/* clang-format on */
+	.mount_exec = true,
+	.file_exec = true,
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(access, mount_exec_file_noexec) {
+	/* clang-format on */
+	.mount_exec = true,
+	.file_exec = false,
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(access, mount_noexec_file_exec) {
+	/* clang-format on */
+	.mount_exec = false,
+	.file_exec = true,
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(access, mount_noexec_file_noexec) {
+	/* clang-format on */
+	.mount_exec = false,
+	.file_exec = false,
+};
+
+static const char binary_path[] = "./false";
+static const char workdir_path[] = "./test-mount";
+static const char reg_file_path[] = "./test-mount/regular_file";
+static const char dir_path[] = "./test-mount/directory";
+static const char block_dev_path[] = "./test-mount/block_device";
+static const char char_dev_path[] = "./test-mount/character_device";
+static const char fifo_path[] = "./test-mount/fifo";
+
+FIXTURE_SETUP(access)
+{
+	int procfd_path_size;
+	static const char path_template[] = "/proc/self/fd/%d";
+	char procfd_path[sizeof(path_template) + 10];
+
+	/* Makes sure we are not already restricted nor locked. */
+	EXPECT_EQ(0, test_secbits_set(0));
+
+	/*
+	 * Cleans previous workspace if any error previously happened (don't
+	 * check errors).
+	 */
+	umount(workdir_path);
+	rmdir(workdir_path);
+
+	/* Creates a clean mount point. */
+	ASSERT_EQ(0, mkdir(workdir_path, 00700));
+	ASSERT_EQ(0, mount("test", workdir_path, "tmpfs",
+			   MS_MGC_VAL | (variant->mount_exec ? 0 : MS_NOEXEC),
+			   "mode=0700,size=9m"));
+
+	/* Creates a regular file. */
+	ASSERT_EQ(0, mknod(reg_file_path,
+			   S_IFREG | (variant->file_exec ? 0700 : 0600), 0));
+	/* Creates a directory. */
+	ASSERT_EQ(0, mkdir(dir_path, variant->file_exec ? 0700 : 0600));
+	/* Creates a character device: /dev/null. */
+	ASSERT_EQ(0, mknod(char_dev_path, S_IFCHR | 0400, makedev(1, 3)));
+	/* Creates a block device: /dev/loop0 */
+	ASSERT_EQ(0, mknod(block_dev_path, S_IFBLK | 0400, makedev(7, 0)));
+	/* Creates a fifo. */
+	ASSERT_EQ(0, mknod(fifo_path, S_IFIFO | 0600, 0));
+
+	/* Creates a regular file without user mount point. */
+	self->memfd = memfd_create("test-exec-probe", MFD_CLOEXEC);
+	ASSERT_LE(0, self->memfd);
+	/* Sets mode, which must be ignored by the exec check. */
+	ASSERT_EQ(0, fchmod(self->memfd, variant->file_exec ? 0700 : 0600));
+
+	/* Creates a pipefs file descriptor. */
+	ASSERT_EQ(0, pipe(self->pipe_fds));
+	procfd_path_size = snprintf(procfd_path, sizeof(procfd_path),
+				    path_template, self->pipe_fds[0]);
+	ASSERT_LT(procfd_path_size, sizeof(procfd_path));
+	self->pipefd = open(procfd_path, O_RDWR | O_CLOEXEC);
+	ASSERT_LE(0, self->pipefd);
+	ASSERT_EQ(0, fchmod(self->pipefd, variant->file_exec ? 0700 : 0600));
+
+	/* Creates a socket file descriptor. */
+	ASSERT_EQ(0, socketpair(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, 0,
+				self->socket_fds));
+}
+
+FIXTURE_TEARDOWN_PARENT(access)
+{
+	/* There is no need to unlink the test files. */
+	EXPECT_EQ(0, umount(workdir_path));
+	EXPECT_EQ(0, rmdir(workdir_path));
+}
+
+static void fill_exec_fd(struct __test_metadata *_metadata, const int fd_out)
+{
+	char buf[1024];
+	size_t len;
+	int fd_in;
+
+	fd_in = open(binary_path, O_CLOEXEC | O_RDONLY);
+	ASSERT_LE(0, fd_in);
+	/* Cannot use copy_file_range(2) because of EXDEV. */
+	len = read(fd_in, buf, sizeof(buf));
+	EXPECT_LE(0, len);
+	while (len > 0) {
+		EXPECT_EQ(len, write(fd_out, buf, len))
+		{
+			TH_LOG("Failed to write: %s (%d)", strerror(errno),
+			       errno);
+		}
+		len = read(fd_in, buf, sizeof(buf));
+		EXPECT_LE(0, len);
+	}
+	EXPECT_EQ(0, close(fd_in));
+}
+
+static void fill_exec_path(struct __test_metadata *_metadata,
+			   const char *const path)
+{
+	int fd_out;
+
+	fd_out = open(path, O_CLOEXEC | O_WRONLY);
+	ASSERT_LE(0, fd_out)
+	{
+		TH_LOG("Failed to open %s: %s", path, strerror(errno));
+	}
+	fill_exec_fd(_metadata, fd_out);
+	EXPECT_EQ(0, close(fd_out));
+}
+
+static void test_exec_fd(struct __test_metadata *_metadata, const int fd,
+			 const int err_code)
+{
+	char *const argv[] = { "", NULL };
+	int access_ret, access_errno;
+
+	/*
+	 * If we really execute fd, filled with the "false" binary, the current
+	 * thread will exits with an error, which will be interpreted by the
+	 * test framework as an error.  With AT_EXECVE_CHECK, we only check a
+	 * potential successful execution.
+	 */
+	access_ret = sys_execveat(fd, "", argv, NULL,
+				  AT_EMPTY_PATH | AT_EXECVE_CHECK);
+	access_errno = errno;
+	if (err_code) {
+		EXPECT_EQ(-1, access_ret);
+		EXPECT_EQ(err_code, access_errno)
+		{
+			TH_LOG("Wrong error for execveat(2): %s (%d)",
+			       strerror(access_errno), errno);
+		}
+	} else {
+		EXPECT_EQ(0, access_ret)
+		{
+			TH_LOG("Access denied: %s", strerror(access_errno));
+		}
+	}
+}
+
+static void test_exec_path(struct __test_metadata *_metadata,
+			   const char *const path, const int err_code)
+{
+	int flags = O_CLOEXEC;
+	int fd;
+
+	/* Do not block on pipes. */
+	if (path == fifo_path)
+		flags |= O_NONBLOCK;
+
+	fd = open(path, flags | O_RDONLY);
+	ASSERT_LE(0, fd)
+	{
+		TH_LOG("Failed to open %s: %s", path, strerror(errno));
+	}
+	test_exec_fd(_metadata, fd, err_code);
+	EXPECT_EQ(0, close(fd));
+}
+
+/* Tests that we don't get ENOEXEC. */
+TEST_F(access, regular_file_empty)
+{
+	const int exec = variant->mount_exec && variant->file_exec;
+
+	test_exec_path(_metadata, reg_file_path, exec ? 0 : EACCES);
+
+	drop_privileges(_metadata);
+	test_exec_path(_metadata, reg_file_path, exec ? 0 : EACCES);
+}
+
+TEST_F(access, regular_file_elf)
+{
+	const int exec = variant->mount_exec && variant->file_exec;
+
+	fill_exec_path(_metadata, reg_file_path);
+
+	test_exec_path(_metadata, reg_file_path, exec ? 0 : EACCES);
+
+	drop_privileges(_metadata);
+	test_exec_path(_metadata, reg_file_path, exec ? 0 : EACCES);
+}
+
+/* Tests that we don't get ENOEXEC. */
+TEST_F(access, memfd_empty)
+{
+	const int exec = variant->file_exec;
+
+	test_exec_fd(_metadata, self->memfd, exec ? 0 : EACCES);
+
+	drop_privileges(_metadata);
+	test_exec_fd(_metadata, self->memfd, exec ? 0 : EACCES);
+}
+
+TEST_F(access, memfd_elf)
+{
+	const int exec = variant->file_exec;
+
+	fill_exec_fd(_metadata, self->memfd);
+
+	test_exec_fd(_metadata, self->memfd, exec ? 0 : EACCES);
+
+	drop_privileges(_metadata);
+	test_exec_fd(_metadata, self->memfd, exec ? 0 : EACCES);
+}
+
+TEST_F(access, non_regular_files)
+{
+	test_exec_path(_metadata, dir_path, EACCES);
+	test_exec_path(_metadata, block_dev_path, EACCES);
+	test_exec_path(_metadata, char_dev_path, EACCES);
+	test_exec_path(_metadata, fifo_path, EACCES);
+	test_exec_fd(_metadata, self->socket_fds[0], EACCES);
+	test_exec_fd(_metadata, self->pipefd, EACCES);
+}
+
+/* clang-format off */
+FIXTURE(secbits) {};
+/* clang-format on */
+
+FIXTURE_VARIANT(secbits)
+{
+	const bool is_privileged;
+	const int error;
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(secbits, priv) {
+	/* clang-format on */
+	.is_privileged = true,
+	.error = 0,
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(secbits, unpriv) {
+	/* clang-format on */
+	.is_privileged = false,
+	.error = EPERM,
+};
+
+FIXTURE_SETUP(secbits)
+{
+	/* Makes sure no exec bits are set. */
+	EXPECT_EQ(0, test_secbits_set(0));
+	EXPECT_EQ(0, prctl(PR_GET_SECUREBITS));
+
+	if (!variant->is_privileged)
+		drop_privileges(_metadata);
+}
+
+FIXTURE_TEARDOWN(secbits)
+{
+}
+
+TEST_F(secbits, legacy)
+{
+	EXPECT_EQ(variant->error, test_secbits_set(0));
+}
+
+#define CHILD(...)                     \
+	do {                           \
+		pid_t child = vfork(); \
+		EXPECT_LE(0, child);   \
+		if (child == 0) {      \
+			__VA_ARGS__;   \
+			_exit(0);      \
+		}                      \
+	} while (0)
+
+TEST_F(secbits, exec)
+{
+	unsigned int secbits = prctl(PR_GET_SECUREBITS);
+
+	secbits |= SECBIT_EXEC_RESTRICT_FILE;
+	EXPECT_EQ(0, test_secbits_set(secbits));
+	EXPECT_EQ(secbits, prctl(PR_GET_SECUREBITS));
+	CHILD(EXPECT_EQ(secbits, prctl(PR_GET_SECUREBITS)));
+
+	secbits |= SECBIT_EXEC_DENY_INTERACTIVE;
+	EXPECT_EQ(0, test_secbits_set(secbits));
+	EXPECT_EQ(secbits, prctl(PR_GET_SECUREBITS));
+	CHILD(EXPECT_EQ(secbits, prctl(PR_GET_SECUREBITS)));
+
+	secbits &= ~(SECBIT_EXEC_RESTRICT_FILE | SECBIT_EXEC_DENY_INTERACTIVE);
+	EXPECT_EQ(0, test_secbits_set(secbits));
+	EXPECT_EQ(secbits, prctl(PR_GET_SECUREBITS));
+	CHILD(EXPECT_EQ(secbits, prctl(PR_GET_SECUREBITS)));
+}
+
+TEST_F(secbits, check_locked_set)
+{
+	unsigned int secbits = prctl(PR_GET_SECUREBITS);
+
+	secbits |= SECBIT_EXEC_RESTRICT_FILE;
+	EXPECT_EQ(0, test_secbits_set(secbits));
+	secbits |= SECBIT_EXEC_RESTRICT_FILE_LOCKED;
+	EXPECT_EQ(0, test_secbits_set(secbits));
+
+	/* Checks lock set but unchanged. */
+	EXPECT_EQ(variant->error, test_secbits_set(secbits));
+	CHILD(EXPECT_EQ(variant->error, test_secbits_set(secbits)));
+
+	secbits &= ~SECBIT_EXEC_RESTRICT_FILE;
+	EXPECT_EQ(EPERM, test_secbits_set(0));
+	CHILD(EXPECT_EQ(EPERM, test_secbits_set(0)));
+}
+
+TEST_F(secbits, check_locked_unset)
+{
+	unsigned int secbits = prctl(PR_GET_SECUREBITS);
+
+	secbits |= SECBIT_EXEC_RESTRICT_FILE_LOCKED;
+	EXPECT_EQ(0, test_secbits_set(secbits));
+
+	/* Checks lock unset but unchanged. */
+	EXPECT_EQ(variant->error, test_secbits_set(secbits));
+	CHILD(EXPECT_EQ(variant->error, test_secbits_set(secbits)));
+
+	secbits &= ~SECBIT_EXEC_RESTRICT_FILE;
+	EXPECT_EQ(EPERM, test_secbits_set(0));
+	CHILD(EXPECT_EQ(EPERM, test_secbits_set(0)));
+}
+
+TEST_F(secbits, restrict_locked_set)
+{
+	unsigned int secbits = prctl(PR_GET_SECUREBITS);
+
+	secbits |= SECBIT_EXEC_DENY_INTERACTIVE;
+	EXPECT_EQ(0, test_secbits_set(secbits));
+	secbits |= SECBIT_EXEC_DENY_INTERACTIVE_LOCKED;
+	EXPECT_EQ(0, test_secbits_set(secbits));
+
+	/* Checks lock set but unchanged. */
+	EXPECT_EQ(variant->error, test_secbits_set(secbits));
+	CHILD(EXPECT_EQ(variant->error, test_secbits_set(secbits)));
+
+	secbits &= ~SECBIT_EXEC_DENY_INTERACTIVE;
+	EXPECT_EQ(EPERM, test_secbits_set(0));
+	CHILD(EXPECT_EQ(EPERM, test_secbits_set(0)));
+}
+
+TEST_F(secbits, restrict_locked_unset)
+{
+	unsigned int secbits = prctl(PR_GET_SECUREBITS);
+
+	secbits |= SECBIT_EXEC_DENY_INTERACTIVE_LOCKED;
+	EXPECT_EQ(0, test_secbits_set(secbits));
+
+	/* Checks lock unset but unchanged. */
+	EXPECT_EQ(variant->error, test_secbits_set(secbits));
+	CHILD(EXPECT_EQ(variant->error, test_secbits_set(secbits)));
+
+	secbits &= ~SECBIT_EXEC_DENY_INTERACTIVE;
+	EXPECT_EQ(EPERM, test_secbits_set(0));
+	CHILD(EXPECT_EQ(EPERM, test_secbits_set(0)));
+}
+
+TEST_HARNESS_MAIN

linux-7.2.3/tools/testing/selftests/exec/config

@@ -0,0 +1,2 @@
+CONFIG_BLK_DEV=y
+CONFIG_BLK_DEV_LOOP=y

linux-7.2.3/tools/testing/selftests/exec/execveat.c

@@ -0,0 +1,520 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2014 Google, Inc.
+ *
+ * Selftests for execveat(2).
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE  /* to get O_PATH, AT_EMPTY_PATH */
+#endif
+#include <sys/sendfile.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "kselftest.h"
+
+#define TESTS_EXPECTED 54
+#define TEST_NAME_LEN (PATH_MAX * 4)
+
+#define CHECK_COMM "CHECK_COMM"
+
+static char longpath[2 * PATH_MAX] = "";
+static char *envp[] = { "IN_TEST=yes", NULL, NULL };
+static char *argv[] = { "execveat", "99", NULL };
+
+static int execveat_(int fd, const char *path, char **argv, char **envp,
+		     int flags)
+{
+#ifdef __NR_execveat
+	return syscall(__NR_execveat, fd, path, argv, envp, flags);
+#else
+	errno = ENOSYS;
+	return -1;
+#endif
+}
+
+#define check_execveat_fail(fd, path, flags, errno)	\
+	_check_execveat_fail(fd, path, flags, errno, #errno)
+static int _check_execveat_fail(int fd, const char *path, int flags,
+				int expected_errno, const char *errno_str)
+{
+	char test_name[TEST_NAME_LEN];
+	int rc;
+
+	errno = 0;
+	snprintf(test_name, sizeof(test_name),
+		 "Check failure of execveat(%d, '%s', %d) with %s",
+		 fd, path?:"(null)", flags, errno_str);
+	rc = execveat_(fd, path, argv, envp, flags);
+
+	if (rc > 0) {
+		ksft_print_msg("unexpected success from execveat(2)\n");
+		ksft_test_result_fail("%s\n", test_name);
+		return 1;
+	}
+	if (errno != expected_errno) {
+		ksft_print_msg("expected errno %d (%s) not %d (%s)\n",
+			       expected_errno, strerror(expected_errno),
+			       errno, strerror(errno));
+		ksft_test_result_fail("%s\n", test_name);
+		return 1;
+	}
+	ksft_test_result_pass("%s\n", test_name);
+	return 0;
+}
+
+static int check_execveat_invoked_rc(int fd, const char *path, int flags,
+				     int expected_rc, int expected_rc2)
+{
+	char test_name[TEST_NAME_LEN];
+	int status;
+	int rc;
+	pid_t child;
+	int pathlen = path ? strlen(path) : 0;
+
+	if (pathlen > 40)
+		snprintf(test_name, sizeof(test_name),
+			 "Check success of execveat(%d, '%.20s...%s', %d)... ",
+			 fd, path, (path + pathlen - 20), flags);
+	else
+		snprintf(test_name, sizeof(test_name),
+			 "Check success of execveat(%d, '%s', %d)... ",
+			 fd, path?:"(null)", flags);
+
+	child = fork();
+	if (child < 0) {
+		ksft_perror("fork() failed");
+		ksft_test_result_fail("%s\n", test_name);
+		return 1;
+	}
+	if (child == 0) {
+		/* Child: do execveat(). */
+		rc = execveat_(fd, path, argv, envp, flags);
+		ksft_print_msg("child execveat() failed, rc=%d errno=%d (%s)\n",
+			       rc, errno, strerror(errno));
+		exit(errno);
+	}
+	/* Parent: wait for & check child's exit status. */
+	rc = waitpid(child, &status, 0);
+	if (rc != child) {
+		ksft_print_msg("waitpid(%d,...) returned %d\n", child, rc);
+		ksft_test_result_fail("%s\n", test_name);
+		return 1;
+	}
+	if (!WIFEXITED(status)) {
+		ksft_print_msg("child %d did not exit cleanly, status=%08x\n",
+			       child, status);
+		ksft_test_result_fail("%s\n", test_name);
+		return 1;
+	}
+	if ((WEXITSTATUS(status) != expected_rc) &&
+	    (WEXITSTATUS(status) != expected_rc2)) {
+		ksft_print_msg("child %d exited with %d neither %d nor %d\n",
+			       child, WEXITSTATUS(status), expected_rc,
+			       expected_rc2);
+		ksft_test_result_fail("%s\n", test_name);
+		return 1;
+	}
+	ksft_test_result_pass("%s\n", test_name);
+	return 0;
+}
+
+static int check_execveat(int fd, const char *path, int flags)
+{
+	return check_execveat_invoked_rc(fd, path, flags, 99, 99);
+}
+
+static char *concat(const char *left, const char *right)
+{
+	char *result = malloc(strlen(left) + strlen(right) + 1);
+
+	strcpy(result, left);
+	strcat(result, right);
+	return result;
+}
+
+static int open_or_die(const char *filename, int flags)
+{
+	int fd = open(filename, flags);
+
+	if (fd < 0)
+		ksft_exit_fail_msg("Failed to open '%s'; "
+			"check prerequisites are available\n", filename);
+	return fd;
+}
+
+static void exe_cp(const char *src, const char *dest)
+{
+	int in_fd = open_or_die(src, O_RDONLY);
+	int out_fd = open(dest, O_RDWR|O_CREAT|O_TRUNC, 0755);
+	struct stat info;
+
+	fstat(in_fd, &info);
+	sendfile(out_fd, in_fd, NULL, info.st_size);
+	close(in_fd);
+	close(out_fd);
+}
+
+#define XX_DIR_LEN 200
+static int check_execveat_pathmax(int root_dfd, const char *src, int is_script)
+{
+	int fail = 0;
+	int ii, count, len;
+	char longname[XX_DIR_LEN + 1];
+	int fd;
+
+	if (*longpath == '\0') {
+		/* Create a filename close to PATH_MAX in length */
+		char *cwd = getcwd(NULL, 0);
+
+		if (!cwd) {
+			ksft_perror("Failed to getcwd()");
+			return 2;
+		}
+		strcpy(longpath, cwd);
+		strcat(longpath, "/");
+		memset(longname, 'x', XX_DIR_LEN - 1);
+		longname[XX_DIR_LEN - 1] = '/';
+		longname[XX_DIR_LEN] = '\0';
+		count = (PATH_MAX - 3 - strlen(cwd)) / XX_DIR_LEN;
+		for (ii = 0; ii < count; ii++) {
+			strcat(longpath, longname);
+			mkdir(longpath, 0755);
+		}
+		len = (PATH_MAX - 3 - strlen(cwd)) - (count * XX_DIR_LEN);
+		if (len <= 0)
+			len = 1;
+		memset(longname, 'y', len);
+		longname[len] = '\0';
+		strcat(longpath, longname);
+		free(cwd);
+	}
+	exe_cp(src, longpath);
+
+	/*
+	 * Execute as a pre-opened file descriptor, which works whether this is
+	 * a script or not (because the interpreter sees a filename like
+	 * "/dev/fd/20").
+	 */
+	fd = open(longpath, O_RDONLY);
+	if (fd > 0) {
+		ksft_print_msg("Invoke copy of '%s' via filename of length %zu:\n",
+			       src, strlen(longpath));
+		fail += check_execveat(fd, "", AT_EMPTY_PATH);
+	} else {
+		ksft_print_msg("Failed to open length %zu filename, errno=%d (%s)\n",
+			       strlen(longpath), errno, strerror(errno));
+		fail++;
+	}
+
+	/*
+	 * Execute as a long pathname relative to "/".  If this is a script,
+	 * the interpreter will launch but fail to open the script because its
+	 * name ("/dev/fd/5/xxx....") is bigger than PATH_MAX.
+	 *
+	 * The failure code is usually 127 (POSIX: "If a command is not found,
+	 * the exit status shall be 127."), but some systems give 126 (POSIX:
+	 * "If the command name is found, but it is not an executable utility,
+	 * the exit status shall be 126."), so allow either.
+	 */
+	if (is_script) {
+		ksft_print_msg("Invoke script via root_dfd and relative filename\n");
+		fail += check_execveat_invoked_rc(root_dfd, longpath + 1, 0,
+						  127, 126);
+	} else {
+		ksft_print_msg("Invoke exec via root_dfd and relative filename\n");
+		fail += check_execveat(root_dfd, longpath + 1, 0);
+	}
+
+	return fail;
+}
+
+static int check_execveat_comm(int fd, char *argv0, char *expected)
+{
+	char buf[128], *old_env, *old_argv0;
+	int ret;
+
+	snprintf(buf, sizeof(buf), CHECK_COMM "=%s", expected);
+
+	old_env = envp[1];
+	envp[1] = buf;
+
+	old_argv0 = argv[0];
+	argv[0] = argv0;
+
+	ksft_print_msg("Check execveat(AT_EMPTY_PATH)'s comm is %s\n",
+		       expected);
+	ret = check_execveat_invoked_rc(fd, "", AT_EMPTY_PATH, 0, 0);
+
+	envp[1] = old_env;
+	argv[0] = old_argv0;
+
+	return ret;
+}
+
+static int run_tests(void)
+{
+	int fail = 0;
+	char *fullname = realpath("execveat", NULL);
+	char *fullname_script = realpath("script", NULL);
+	char *fullname_symlink = concat(fullname, ".symlink");
+	int subdir_dfd = open_or_die("subdir", O_DIRECTORY|O_RDONLY);
+	int subdir_dfd_ephemeral = open_or_die("subdir.ephemeral",
+					       O_DIRECTORY|O_RDONLY);
+	int dot_dfd = open_or_die(".", O_DIRECTORY|O_RDONLY);
+	int root_dfd = open_or_die("/", O_DIRECTORY|O_RDONLY);
+	int dot_dfd_path = open_or_die(".", O_DIRECTORY|O_RDONLY|O_PATH);
+	int dot_dfd_cloexec = open_or_die(".", O_DIRECTORY|O_RDONLY|O_CLOEXEC);
+	int fd = open_or_die("execveat", O_RDONLY);
+	int fd_path = open_or_die("execveat", O_RDONLY|O_PATH);
+	int fd_symlink = open_or_die("execveat.symlink", O_RDONLY);
+	int fd_denatured = open_or_die("execveat.denatured", O_RDONLY);
+	int fd_denatured_path = open_or_die("execveat.denatured",
+					    O_RDONLY|O_PATH);
+	int fd_script = open_or_die("script", O_RDONLY);
+	int fd_ephemeral = open_or_die("execveat.ephemeral", O_RDONLY);
+	int fd_ephemeral_path = open_or_die("execveat.path.ephemeral",
+					    O_RDONLY|O_PATH);
+	int fd_script_ephemeral = open_or_die("script.ephemeral", O_RDONLY);
+	int fd_cloexec = open_or_die("execveat", O_RDONLY|O_CLOEXEC);
+	int fd_script_cloexec = open_or_die("script", O_RDONLY|O_CLOEXEC);
+
+	/* Check if we have execveat at all, and bail early if not */
+	errno = 0;
+	execveat_(-1, NULL, NULL, NULL, 0);
+	if (errno == ENOSYS) {
+		ksft_exit_skip(
+			"ENOSYS calling execveat - no kernel support?\n");
+	}
+
+	/* Change file position to confirm it doesn't affect anything */
+	lseek(fd, 10, SEEK_SET);
+
+	/* Normal executable file: */
+	/*   dfd + path */
+	fail += check_execveat(subdir_dfd, "../execveat", 0);
+	fail += check_execveat(dot_dfd, "execveat", 0);
+	fail += check_execveat(dot_dfd_path, "execveat", 0);
+	/*   absolute path */
+	fail += check_execveat(AT_FDCWD, fullname, 0);
+	/*   absolute path with nonsense dfd */
+	fail += check_execveat(99, fullname, 0);
+	/*   fd + no path */
+	fail += check_execveat(fd, "", AT_EMPTY_PATH);
+	/*   O_CLOEXEC fd + no path */
+	fail += check_execveat(fd_cloexec, "", AT_EMPTY_PATH);
+	/*   O_PATH fd */
+	fail += check_execveat(fd_path, "", AT_EMPTY_PATH);
+
+	/* Mess with executable file that's already open: */
+	/*   fd + no path to a file that's been renamed */
+	rename("execveat.ephemeral", "execveat.moved");
+	fail += check_execveat(fd_ephemeral, "", AT_EMPTY_PATH);
+	/*   fd + no path to a file that's been deleted */
+	unlink("execveat.moved"); /* remove the file now fd open */
+	fail += check_execveat(fd_ephemeral, "", AT_EMPTY_PATH);
+
+	/* Mess with executable file that's already open with O_PATH */
+	/*   fd + no path to a file that's been deleted */
+	unlink("execveat.path.ephemeral");
+	fail += check_execveat(fd_ephemeral_path, "", AT_EMPTY_PATH);
+
+	/* Invalid argument failures */
+	fail += check_execveat_fail(fd, "", 0, ENOENT);
+	fail += check_execveat_fail(fd, NULL, AT_EMPTY_PATH, EFAULT);
+
+	/* Symlink to executable file: */
+	/*   dfd + path */
+	fail += check_execveat(dot_dfd, "execveat.symlink", 0);
+	fail += check_execveat(dot_dfd_path, "execveat.symlink", 0);
+	/*   absolute path */
+	fail += check_execveat(AT_FDCWD, fullname_symlink, 0);
+	/*   fd + no path, even with AT_SYMLINK_NOFOLLOW (already followed) */
+	fail += check_execveat(fd_symlink, "", AT_EMPTY_PATH);
+	fail += check_execveat(fd_symlink, "",
+			       AT_EMPTY_PATH|AT_SYMLINK_NOFOLLOW);
+
+	/* Symlink fails when AT_SYMLINK_NOFOLLOW set: */
+	/*   dfd + path */
+	fail += check_execveat_fail(dot_dfd, "execveat.symlink",
+				    AT_SYMLINK_NOFOLLOW, ELOOP);
+	fail += check_execveat_fail(dot_dfd_path, "execveat.symlink",
+				    AT_SYMLINK_NOFOLLOW, ELOOP);
+	/*   absolute path */
+	fail += check_execveat_fail(AT_FDCWD, fullname_symlink,
+				    AT_SYMLINK_NOFOLLOW, ELOOP);
+
+	/*  Non-regular file failure */
+	fail += check_execveat_fail(dot_dfd, "pipe", 0, EACCES);
+	unlink("pipe");
+
+	/* Shell script wrapping executable file: */
+	/*   dfd + path */
+	fail += check_execveat(subdir_dfd, "../script", 0);
+	fail += check_execveat(dot_dfd, "script", 0);
+	fail += check_execveat(dot_dfd_path, "script", 0);
+	/*   absolute path */
+	fail += check_execveat(AT_FDCWD, fullname_script, 0);
+	/*   fd + no path */
+	fail += check_execveat(fd_script, "", AT_EMPTY_PATH);
+	fail += check_execveat(fd_script, "",
+			       AT_EMPTY_PATH|AT_SYMLINK_NOFOLLOW);
+	/*   O_CLOEXEC fd fails for a script (as script file inaccessible) */
+	fail += check_execveat_fail(fd_script_cloexec, "", AT_EMPTY_PATH,
+				    ENOENT);
+	fail += check_execveat_fail(dot_dfd_cloexec, "script", 0, ENOENT);
+
+	/* Mess with script file that's already open: */
+	/*   fd + no path to a file that's been renamed */
+	rename("script.ephemeral", "script.moved");
+	fail += check_execveat(fd_script_ephemeral, "", AT_EMPTY_PATH);
+	/*   fd + no path to a file that's been deleted */
+	unlink("script.moved"); /* remove the file while fd open */
+	fail += check_execveat(fd_script_ephemeral, "", AT_EMPTY_PATH);
+
+	/* Rename a subdirectory in the path: */
+	rename("subdir.ephemeral", "subdir.moved");
+	fail += check_execveat(subdir_dfd_ephemeral, "../script", 0);
+	fail += check_execveat(subdir_dfd_ephemeral, "script", 0);
+	/* Remove the subdir and its contents */
+	unlink("subdir.moved/script");
+	unlink("subdir.moved");
+	/* Shell loads via deleted subdir OK because name starts with .. */
+	fail += check_execveat(subdir_dfd_ephemeral, "../script", 0);
+	fail += check_execveat_fail(subdir_dfd_ephemeral, "script", 0, ENOENT);
+
+	/* Flag values other than AT_SYMLINK_NOFOLLOW => EINVAL */
+	fail += check_execveat_fail(dot_dfd, "execveat", 0xFFFF, EINVAL);
+	/* Invalid path => ENOENT */
+	fail += check_execveat_fail(dot_dfd, "no-such-file", 0, ENOENT);
+	fail += check_execveat_fail(dot_dfd_path, "no-such-file", 0, ENOENT);
+	fail += check_execveat_fail(AT_FDCWD, "no-such-file", 0, ENOENT);
+	/* Attempt to execute directory => EACCES */
+	fail += check_execveat_fail(dot_dfd, "", AT_EMPTY_PATH, EACCES);
+	/* Attempt to execute non-executable => EACCES */
+	fail += check_execveat_fail(dot_dfd, "Makefile", 0, EACCES);
+	fail += check_execveat_fail(fd_denatured, "", AT_EMPTY_PATH, EACCES);
+	fail += check_execveat_fail(fd_denatured_path, "", AT_EMPTY_PATH,
+				    EACCES);
+	/* Attempt to execute nonsense FD => EBADF */
+	fail += check_execveat_fail(99, "", AT_EMPTY_PATH, EBADF);
+	fail += check_execveat_fail(99, "execveat", 0, EBADF);
+	/* Attempt to execute relative to non-directory => ENOTDIR */
+	fail += check_execveat_fail(fd, "execveat", 0, ENOTDIR);
+
+	fail += check_execveat_pathmax(root_dfd, "execveat", 0);
+	fail += check_execveat_pathmax(root_dfd, "script", 1);
+
+	/* /proc/pid/comm gives filename by default */
+	fail += check_execveat_comm(fd, "sentinel", "execveat");
+	/* /proc/pid/comm gives argv[0] when invoked via link */
+	fail += check_execveat_comm(fd_symlink, "sentinel", "execveat");
+	/* /proc/pid/comm gives filename if NULL is passed */
+	fail += check_execveat_comm(fd, NULL, "execveat");
+
+	return fail;
+}
+
+static void prerequisites(void)
+{
+	int fd;
+	const char *script = "#!/bin/bash\nexit $*\n";
+
+	/* Create ephemeral copies of files */
+	exe_cp("execveat", "execveat.ephemeral");
+	exe_cp("execveat", "execveat.path.ephemeral");
+	exe_cp("script", "script.ephemeral");
+	mkdir("subdir.ephemeral", 0755);
+
+	fd = open("subdir.ephemeral/script", O_RDWR|O_CREAT|O_TRUNC, 0755);
+	write(fd, script, strlen(script));
+	close(fd);
+
+	mkfifo("pipe", 0755);
+}
+
+int main(int argc, char **argv)
+{
+	int ii;
+	int rc;
+	const char *verbose = getenv("VERBOSE");
+	const char *check_comm = getenv(CHECK_COMM);
+
+	if (argc >= 2 || check_comm) {
+		/*
+		 * If we are invoked with an argument, or no arguments but a
+		 * command to check, don't run tests.
+		 */
+		const char *in_test = getenv("IN_TEST");
+
+		if (verbose) {
+			ksft_print_msg("invoked with:\n");
+			for (ii = 0; ii < argc; ii++)
+				ksft_print_msg("\t[%d]='%s\n'", ii, argv[ii]);
+		}
+
+		/* If the tests wanted us to check the command, do so. */
+		if (check_comm) {
+			/* TASK_COMM_LEN == 16 */
+			char buf[32];
+			int fd, ret;
+
+			fd = open("/proc/self/comm", O_RDONLY);
+			if (fd < 0) {
+				ksft_perror("open() comm failed");
+				exit(1);
+			}
+
+			ret = read(fd, buf, sizeof(buf));
+			if (ret < 0) {
+				ksft_perror("read() comm failed");
+				close(fd);
+				exit(1);
+			}
+			close(fd);
+
+			// trim off the \n
+			buf[ret-1] = 0;
+
+			if (strcmp(buf, check_comm)) {
+				ksft_print_msg("bad comm, got: %s expected: %s\n",
+					       buf, check_comm);
+				exit(1);
+			}
+
+			exit(0);
+		}
+
+		/* Check expected environment transferred. */
+		if (!in_test || strcmp(in_test, "yes") != 0) {
+			ksft_print_msg("no IN_TEST=yes in env\n");
+			return 1;
+		}
+
+		/* Use the final argument as an exit code. */
+		rc = atoi(argv[argc - 1]);
+		exit(rc);
+	} else {
+		ksft_print_header();
+		ksft_set_plan(TESTS_EXPECTED);
+		prerequisites();
+		if (verbose)
+			envp[1] = "VERBOSE=1";
+		rc = run_tests();
+		if (rc > 0)
+			printf("%d tests failed\n", rc);
+		ksft_finished();
+	}
+
+	return rc;
+}

linux-7.2.3/tools/testing/selftests/exec/false.c

@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0
+int main(void)
+{
+	return 1;
+}

linux-7.2.3/tools/testing/selftests/exec/load_address.c

@@ -0,0 +1,105 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <link.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include "kselftest.h"
+
+struct Statistics {
+	unsigned long long load_address;
+	unsigned long long alignment;
+	bool interp;
+};
+
+int ExtractStatistics(struct dl_phdr_info *info, size_t size, void *data)
+{
+	struct Statistics *stats = (struct Statistics *) data;
+	int i;
+
+	if (info->dlpi_name != NULL && info->dlpi_name[0] != '\0') {
+		// Ignore headers from other than the executable.
+		return 2;
+	}
+
+	stats->load_address = (unsigned long long) info->dlpi_addr;
+	stats->alignment = 0;
+
+	for (i = 0; i < info->dlpi_phnum; i++) {
+		unsigned long long align;
+
+		if (info->dlpi_phdr[i].p_type == PT_INTERP) {
+			stats->interp = true;
+			continue;
+		}
+
+		if (info->dlpi_phdr[i].p_type != PT_LOAD)
+			continue;
+
+		align = info->dlpi_phdr[i].p_align;
+
+		if (align > stats->alignment)
+			stats->alignment = align;
+	}
+
+	return 1;  // Terminate dl_iterate_phdr.
+}
+
+int main(int argc, char **argv)
+{
+	struct Statistics extracted = { };
+	unsigned long long misalign, pow2;
+	bool interp_needed;
+	char buf[1024];
+	FILE *maps;
+	int ret;
+
+	ksft_print_header();
+	ksft_set_plan(4);
+
+	/* Dump maps file for debugging reference. */
+	maps = fopen("/proc/self/maps", "r");
+	if (!maps)
+		ksft_exit_fail_msg("FAILED: /proc/self/maps: %s\n", strerror(errno));
+	while (fgets(buf, sizeof(buf), maps)) {
+		ksft_print_msg("%s", buf);
+	}
+	fclose(maps);
+
+	/* Walk the program headers. */
+	ret = dl_iterate_phdr(ExtractStatistics, &extracted);
+	if (ret != 1)
+		ksft_exit_fail_msg("FAILED: dl_iterate_phdr\n");
+
+	/* Report our findings. */
+	ksft_print_msg("load_address=%#llx alignment=%#llx\n",
+		       extracted.load_address, extracted.alignment);
+
+	/* If we're named with ".static." we expect no INTERP. */
+	interp_needed = strstr(argv[0], ".static.") == NULL;
+
+	/* Were we built as expected? */
+	ksft_test_result(interp_needed == extracted.interp,
+			 "%s INTERP program header %s\n",
+			 interp_needed ? "Wanted" : "Unwanted",
+			 extracted.interp ? "seen" : "missing");
+
+	/* Did we find an alignment? */
+	ksft_test_result(extracted.alignment != 0,
+			 "Alignment%s found\n", extracted.alignment ? "" : " NOT");
+
+	/* Is the alignment sane? */
+	pow2 = extracted.alignment & (extracted.alignment - 1);
+	ksft_test_result(pow2 == 0,
+			 "Alignment is%s a power of 2: %#llx\n",
+			 pow2 == 0 ? "" : " NOT", extracted.alignment);
+
+	/* Is the load address aligned? */
+	misalign = extracted.load_address & (extracted.alignment - 1);
+	ksft_test_result(misalign == 0, "Load Address is %saligned (%#llx)\n",
+			 misalign ? "MIS" : "", misalign);
+
+	ksft_finished();
+}

linux-7.2.3/tools/testing/selftests/exec/non-regular.c

@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include <sys/types.h>
+
+#include "kselftest_harness.h"
+
+/* Remove a file, ignoring the result if it didn't exist. */
+void rm(struct __test_metadata *_metadata, const char *pathname,
+	int is_dir)
+{
+	int rc;
+
+	if (is_dir)
+		rc = rmdir(pathname);
+	else
+		rc = unlink(pathname);
+
+	if (rc < 0) {
+		ASSERT_EQ(errno, ENOENT) {
+			TH_LOG("Not ENOENT: %s", pathname);
+		}
+	} else {
+		ASSERT_EQ(rc, 0) {
+			TH_LOG("Failed to remove: %s", pathname);
+		}
+	}
+}
+
+FIXTURE(file) {
+	char *pathname;
+	int is_dir;
+};
+
+FIXTURE_VARIANT(file)
+{
+	const char *name;
+	int expected;
+	int is_dir;
+	void (*setup)(struct __test_metadata *_metadata,
+		      FIXTURE_DATA(file) *self,
+		      const FIXTURE_VARIANT(file) *variant);
+	int major, minor, mode; /* for mknod() */
+};
+
+void setup_link(struct __test_metadata *_metadata,
+		FIXTURE_DATA(file) *self,
+		const FIXTURE_VARIANT(file) *variant)
+{
+	const char * const paths[] = {
+		"/bin/true",
+		"/usr/bin/true",
+	};
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(paths); i++) {
+		if (access(paths[i], X_OK) == 0) {
+			ASSERT_EQ(symlink(paths[i], self->pathname), 0);
+			return;
+		}
+	}
+	ASSERT_EQ(1, 0) {
+		TH_LOG("Could not find viable 'true' binary");
+	}
+}
+
+FIXTURE_VARIANT_ADD(file, S_IFLNK)
+{
+	.name = "S_IFLNK",
+	.expected = ELOOP,
+	.setup = setup_link,
+};
+
+void setup_dir(struct __test_metadata *_metadata,
+	       FIXTURE_DATA(file) *self,
+	       const FIXTURE_VARIANT(file) *variant)
+{
+	ASSERT_EQ(mkdir(self->pathname, 0755), 0);
+}
+
+FIXTURE_VARIANT_ADD(file, S_IFDIR)
+{
+	.name = "S_IFDIR",
+	.is_dir = 1,
+	.expected = EACCES,
+	.setup = setup_dir,
+};
+
+void setup_node(struct __test_metadata *_metadata,
+		FIXTURE_DATA(file) *self,
+		const FIXTURE_VARIANT(file) *variant)
+{
+	dev_t dev;
+	int rc;
+
+	dev = makedev(variant->major, variant->minor);
+	rc = mknod(self->pathname, 0755 | variant->mode, dev);
+	ASSERT_EQ(rc, 0) {
+		if (errno == EPERM)
+			SKIP(return, "Please run as root; cannot mknod(%s)",
+				variant->name);
+	}
+}
+
+FIXTURE_VARIANT_ADD(file, S_IFBLK)
+{
+	.name = "S_IFBLK",
+	.expected = EACCES,
+	.setup = setup_node,
+	/* /dev/loop0 */
+	.major = 7,
+	.minor = 0,
+	.mode = S_IFBLK,
+};
+
+FIXTURE_VARIANT_ADD(file, S_IFCHR)
+{
+	.name = "S_IFCHR",
+	.expected = EACCES,
+	.setup = setup_node,
+	/* /dev/zero */
+	.major = 1,
+	.minor = 5,
+	.mode = S_IFCHR,
+};
+
+void setup_fifo(struct __test_metadata *_metadata,
+		FIXTURE_DATA(file) *self,
+		const FIXTURE_VARIANT(file) *variant)
+{
+	ASSERT_EQ(mkfifo(self->pathname, 0755), 0);
+}
+
+FIXTURE_VARIANT_ADD(file, S_IFIFO)
+{
+	.name = "S_IFIFO",
+	.expected = EACCES,
+	.setup = setup_fifo,
+};
+
+FIXTURE_SETUP(file)
+{
+	ASSERT_GT(asprintf(&self->pathname, "%s.test", variant->name), 6);
+	self->is_dir = variant->is_dir;
+
+	rm(_metadata, self->pathname, variant->is_dir);
+	variant->setup(_metadata, self, variant);
+}
+
+FIXTURE_TEARDOWN(file)
+{
+	rm(_metadata, self->pathname, self->is_dir);
+}
+
+TEST_F(file, exec_errno)
+{
+	char * const argv[2] = { (char * const)self->pathname, NULL };
+
+	EXPECT_LT(execv(argv[0], argv), 0);
+	EXPECT_EQ(errno, variant->expected);
+}
+
+/* S_IFSOCK */
+FIXTURE(sock)
+{
+	int fd;
+};
+
+FIXTURE_SETUP(sock)
+{
+	self->fd = socket(AF_INET, SOCK_STREAM, 0);
+	ASSERT_GE(self->fd, 0);
+}
+
+FIXTURE_TEARDOWN(sock)
+{
+	if (self->fd >= 0)
+		ASSERT_EQ(close(self->fd), 0);
+}
+
+TEST_F(sock, exec_errno)
+{
+	char * const argv[2] = { " magic socket ", NULL };
+	char * const envp[1] = { NULL };
+
+	EXPECT_LT(fexecve(self->fd, argv, envp), 0);
+	EXPECT_EQ(errno, EACCES);
+}
+
+TEST_HARNESS_MAIN

linux-7.2.3/tools/testing/selftests/exec/null-argv.c

@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Test that empty argvs are swapped out for a single empty string. */
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include "kselftest.h"
+
+#define FORK(exec)				\
+do {						\
+	pid = fork();				\
+	if (pid == 0) {				\
+		/* Child */			\
+		exec; /* Some kind of exec */	\
+		perror("# " #exec);		\
+		return 1;			\
+	}					\
+	check_result(pid, #exec);		\
+} while (0)
+
+void check_result(pid_t pid, const char *msg)
+{
+	int wstatus;
+
+	if (pid == (pid_t)-1) {
+		perror("# fork");
+		ksft_test_result_fail("fork failed: %s\n", msg);
+		return;
+	}
+	if (waitpid(pid, &wstatus, 0) < 0) {
+		perror("# waitpid");
+		ksft_test_result_fail("waitpid failed: %s\n", msg);
+		return;
+	}
+	if (!WIFEXITED(wstatus)) {
+		ksft_test_result_fail("child did not exit: %s\n", msg);
+		return;
+	}
+	if (WEXITSTATUS(wstatus) != 0) {
+		ksft_test_result_fail("non-zero exit: %s\n", msg);
+		return;
+	}
+	ksft_test_result_pass("%s\n", msg);
+}
+
+int main(int argc, char *argv[], char *envp[])
+{
+	pid_t pid;
+	static char * const args[] = { NULL };
+	static char * const str[] = { "", NULL };
+
+	/* argc counting checks */
+	if (argc < 1) {
+		fprintf(stderr, "# FAIL: saw argc == 0 (old kernel?)\n");
+		return 1;
+	}
+	if (argc != 1) {
+		fprintf(stderr, "# FAIL: unknown argc (%d)\n", argc);
+		return 1;
+	}
+	if (argv[0][0] == '\0') {
+		/* Good, we found a NULL terminated string at argv[0]! */
+		return 0;
+	}
+
+	/* Test runner. */
+	ksft_print_header();
+	ksft_set_plan(5);
+
+	FORK(execve(argv[0], str, NULL));
+	FORK(execve(argv[0], NULL, NULL));
+	FORK(execve(argv[0], NULL, envp));
+	FORK(execve(argv[0], args, NULL));
+	FORK(execve(argv[0], args, envp));
+
+	ksft_exit(ksft_cnt.ksft_pass == ksft_plan);
+}

linux-7.2.3/tools/testing/selftests/exec/recursion-depth.c

@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2019 Alexey Dobriyan <adobriyan@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+/* Test that pointing #! script interpreter to self doesn't recurse. */
+#include <errno.h>
+#include <sched.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/mount.h>
+#include <unistd.h>
+#include "kselftest.h"
+
+int main(void)
+{
+	int fd, rv;
+
+	ksft_print_header();
+	ksft_set_plan(1);
+
+	if (unshare(CLONE_NEWNS) == -1) {
+		if (errno == ENOSYS || errno == EPERM) {
+			ksft_test_result_skip("error: unshare, errno %d\n", errno);
+			ksft_finished();
+		}
+		ksft_exit_fail_perror("error: unshare");
+	}
+
+	if (mount(NULL, "/", NULL, MS_PRIVATE | MS_REC, NULL) == -1)
+		ksft_exit_fail_perror("error: mount '/'");
+
+	/* Require "exec" filesystem. */
+	if (mount(NULL, "/tmp", "ramfs", 0, NULL) == -1)
+		ksft_exit_fail_perror("error: mount ramfs");
+
+#define FILENAME "/tmp/1"
+
+	fd = creat(FILENAME, 0700);
+	if (fd == -1)
+		ksft_exit_fail_perror("error: creat");
+
+#define S "#!" FILENAME "\n"
+	if (write(fd, S, strlen(S)) != strlen(S))
+		ksft_exit_fail_perror("error: write");
+
+	close(fd);
+
+	rv = execve(FILENAME, NULL, NULL);
+	ksft_test_result(rv == -1 && errno == ELOOP,
+			 "execve failed as expected (ret %d, errno %d)\n", rv, errno);
+	ksft_finished();
+}