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Date: Wed, 22 Oct 2014 12:44:28 +0100
From: David Drysdale <drysdale@...gle.com>
To: "Eric W. Biederman" <ebiederm@...ssion.com>,
Andy Lutomirski <luto@...capital.net>,
Alexander Viro <viro@...iv.linux.org.uk>,
Meredydd Luff <meredydd@...atehouse.org>,
linux-kernel@...r.kernel.org
Cc: Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Kees Cook <keescook@...omium.org>,
Arnd Bergmann <arnd@...db.de>, x86@...nel.org,
linux-arch@...r.kernel.org, linux-api@...r.kernel.org,
David Drysdale <drysdale@...gle.com>
Subject: [PATCHv5 2/3] syscalls,x86: add selftest for execveat(2)
Signed-off-by: David Drysdale <drysdale@...gle.com>
---
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/exec/.gitignore | 6 +
tools/testing/selftests/exec/Makefile | 22 +++
tools/testing/selftests/exec/execveat.c | 295 ++++++++++++++++++++++++++++++++
4 files changed, 324 insertions(+)
create mode 100644 tools/testing/selftests/exec/.gitignore
create mode 100644 tools/testing/selftests/exec/Makefile
create mode 100644 tools/testing/selftests/exec/execveat.c
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 36ff2e4c7b6f..210cf68b3511 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -14,6 +14,7 @@ TARGETS += powerpc
TARGETS += user
TARGETS += sysctl
TARGETS += firmware
+TARGETS += exec
TARGETS_HOTPLUG = cpu-hotplug
TARGETS_HOTPLUG += memory-hotplug
diff --git a/tools/testing/selftests/exec/.gitignore b/tools/testing/selftests/exec/.gitignore
new file mode 100644
index 000000000000..349a786899a7
--- /dev/null
+++ b/tools/testing/selftests/exec/.gitignore
@@ -0,0 +1,6 @@
+subdir*
+script*
+execveat
+execveat.symlink
+execveat.moved
+execveat.ephemeral
diff --git a/tools/testing/selftests/exec/Makefile b/tools/testing/selftests/exec/Makefile
new file mode 100644
index 000000000000..428cb1d2a06a
--- /dev/null
+++ b/tools/testing/selftests/exec/Makefile
@@ -0,0 +1,22 @@
+CC = $(CROSS_COMPILE)gcc
+CFLAGS = -Wall
+BINARIES = execveat
+DEPS = execveat.symlink script subdir
+all: $(BINARIES) $(DEPS)
+
+subdir:
+ mkdir -p $@
+script:
+ echo '#!/bin/sh' > $@
+ echo 'exit $$*' >> $@
+ chmod +x $@
+execveat.symlink: execveat
+ ln -s -f $< $@
+%: %.c
+ $(CC) $(CFLAGS) -o $@ $^
+
+run_tests: all
+ ./execveat
+
+clean:
+ rm -rf $(BINARIES) $(DEPS) subdir.moved execveat.moved
diff --git a/tools/testing/selftests/exec/execveat.c b/tools/testing/selftests/exec/execveat.c
new file mode 100644
index 000000000000..1f2722ed3847
--- /dev/null
+++ b/tools/testing/selftests/exec/execveat.c
@@ -0,0 +1,295 @@
+/*
+ * Copyright (c) 2014 Google, Inc.
+ *
+ * Licensed under the terms of the GNU GPL License version 2
+ *
+ * Selftests for execveat(2).
+ */
+
+#define _GNU_SOURCE /* to get O_PATH, AT_EMPTY_PATH */
+#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>
+
+static char *envp[] = { "IN_TEST=yes", 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)
+{
+ int rc;
+
+ errno = 0;
+ printf("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) {
+ printf("[FAIL] (unexpected success from execveat(2))\n");
+ return 1;
+ }
+ if (errno != expected_errno) {
+ printf("[FAIL] (expected errno %d (%s) not %d (%s)\n",
+ expected_errno, strerror(expected_errno),
+ errno, strerror(errno));
+ return 1;
+ }
+ printf("[OK]\n");
+ return 0;
+}
+
+static int check_execveat_invoked_rc(int fd, const char *path, int flags,
+ int expected_rc)
+{
+ int status;
+ int rc;
+ pid_t child;
+
+ printf("Check success of execveat(%d, '%s', %d)... ",
+ fd, path?:"(null)", flags);
+ child = fork();
+ if (child < 0) {
+ printf("[FAIL] (fork() failed)\n");
+ return 1;
+ }
+ if (child == 0) {
+ /* Child: do execveat(). */
+ rc = execveat_(fd, path, argv, envp, flags);
+ printf("[FAIL]: execveat() failed, rc=%d errno=%d (%s)\n",
+ rc, errno, strerror(errno));
+ exit(1); /* should not reach here */
+ }
+ /* Parent: wait for & check child's exit status. */
+ rc = waitpid(child, &status, 0);
+ if (rc != child) {
+ printf("[FAIL] (waitpid(%d,...) returned %d)\n", child, rc);
+ return 1;
+ }
+ if (!WIFEXITED(status)) {
+ printf("[FAIL] (child %d did not exit cleanly, status=%08x)\n",
+ child, status);
+ return 1;
+ }
+ if (WEXITSTATUS(status) != expected_rc) {
+ printf("[FAIL] (child %d exited with %d not %d)\n",
+ child, WEXITSTATUS(status), expected_rc);
+ return 1;
+ }
+ printf("[OK]\n");
+ return 0;
+}
+
+static int check_execveat(int fd, const char *path, int flags)
+{
+ return check_execveat_invoked_rc(fd, path, flags, 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) {
+ printf("Failed to open '%s'; "
+ "check prerequisites are available\n", filename);
+ exit(1);
+ }
+ return fd;
+}
+
+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 dot_dfd_path = open_or_die(".", O_DIRECTORY|O_RDONLY|O_PATH);
+ 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_script = open_or_die("script", O_RDONLY);
+ int fd_ephemeral = open_or_die("execveat.ephemeral", O_RDONLY);
+ int fd_script_ephemeral = open_or_die("script.ephemeral", O_RDONLY);
+
+ /* 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);
+
+ /* 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);
+
+ /* 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);
+
+ /* 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);
+
+ /* 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);
+ /* Attempt to execute file opened with O_PATH => EBADF */
+ fail |= check_execveat_fail(dot_dfd_path, "", AT_EMPTY_PATH, EBADF);
+ fail |= check_execveat_fail(fd_path, "", AT_EMPTY_PATH, EBADF);
+ /* 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);
+
+ return fail ? -1 : 0;
+}
+
+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);
+}
+
+void prerequisites(void)
+{
+ int fd;
+ const char *script = "#!/bin/sh\nexit $*\n";
+
+ /* Create ephemeral copies of files */
+ exe_cp("execveat", "execveat.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);
+}
+
+int main(int argc, char **argv)
+{
+ int rc;
+
+ if (argc >= 2) {
+ /* If we are invoked with an argument, exit immediately. */
+ /* Check expected environment transferred. */
+ const char *in_test = getenv("IN_TEST");
+
+ if (!in_test || strcmp(in_test, "yes") != 0) {
+ printf("[FAIL] (no IN_TEST=yes in env)\n");
+ return 1;
+ }
+
+ /* Use the final argument as an exit code. */
+ rc = atoi(argv[argc - 1]);
+ fflush(stdout);
+ } else {
+ prerequisites();
+ rc = run_tests();
+ }
+ return rc;
+}
--
2.1.0.rc2.206.gedb03e5
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