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Message-Id: <1401181330-11997-3-git-send-email-drysdale@google.com>
Date: Tue, 27 May 2014 10:02:09 +0100
From: David Drysdale <drysdale@...gle.com>
To: 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, David Drysdale <drysdale@...gle.com>
Subject: [PATCHv4 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 | 32 ++++
tools/testing/selftests/exec/execveat.c | 251 ++++++++++++++++++++++++++++++++
4 files changed, 290 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 32487ed18354..26b7e6410fcd 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -10,6 +10,7 @@ TARGETS += timers
TARGETS += vm
TARGETS += powerpc
TARGETS += user
+TARGETS += exec
all:
for TARGET in $(TARGETS); do \
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..55771ed05dda
--- /dev/null
+++ b/tools/testing/selftests/exec/Makefile
@@ -0,0 +1,32 @@
+CC = $(CROSS_COMPILE)gcc
+CFLAGS = -Wall
+BINARIES = execveat
+DEPS = execveat.symlink script execveat.ephemeral script.ephemeral subdir subdir.ephemeral subdir.ephemeral/script
+all: $(BINARIES) $(DEPS)
+
+subdir:
+ mkdir -p $@
+subdir.ephemeral:
+ mkdir -p $@
+subdir.ephemeral/script: | subdir.ephemeral
+ echo '#!/bin/sh' > $@
+ echo 'exit $$*' >> $@
+ chmod +x $@
+script:
+ echo '#!/bin/sh' > $@
+ echo 'exit $$*' >> $@
+ chmod +x $@
+script.ephemeral: script
+ cp $< $@
+execveat.symlink: execveat
+ ln -s -f $< $@
+execveat.ephemeral: execveat
+ cp $< $@
+%: %.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..f67862fa3f38
--- /dev/null
+++ b/tools/testing/selftests/exec/execveat.c
@@ -0,0 +1,251 @@
+/*
+ * 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 */
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/syscall.h>
+#include <sys/stat.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <limits.h>
+#include <stdlib.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)
+{
+ errno = 0;
+ printf("Check failure of execveat(%d, '%s', %d) with %s... ",
+ fd, path?:"(null)", flags, errno_str);
+ int 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, NULL, 0);
+
+ /* 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, NULL, 0);
+ /* fd + no path to a file that's been deleted */
+ unlink("execveat.moved"); /* remove the file now fd open */
+ fail |= check_execveat(fd_ephemeral, NULL, 0);
+
+ /* 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, NULL, 0);
+ fail |= check_execveat(fd_symlink, NULL, 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, NULL, 0);
+ fail |= check_execveat(fd_script, NULL, 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, NULL, 0);
+ /* fd + no path to a file that's been deleted */
+ unlink("script.moved"); /* remove the file while fd open */
+ /* Shell attempts to load the deleted file but fails => rc=127 */
+ fail |= check_execveat_invoked_rc(fd_script_ephemeral, NULL, 0, 127);
+
+ /* 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, NULL, 0, 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, NULL, 0, EBADF);
+ fail |= check_execveat_fail(fd_path, NULL, 0, EBADF);
+ /* Attempt to execute nonsense FD => EBADF */
+ fail |= check_execveat_fail(99, NULL, 0, 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;
+}
+
+int main(int argc, char **argv)
+{
+ if (argc >= 2) {
+ /* If we are invoked with an argument, exit immediately. */
+ /* Check expected environment transferred. */
+ if (strcmp(getenv("IN_TEST"), "yes") != 0) {
+ printf("[FAIL] (no IN_TEST=yes in env)\n");
+ return 1;
+ }
+
+ /* Use the argument as an exit code. */
+ int rc = atoi(argv[1]);
+ fflush(stdout);
+ return rc;
+ } else {
+ return run_tests();
+ }
+}
--
1.9.1.423.g4596e3a
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