2 * Copyright (c) 2014 Google, Inc.
4 * Licensed under the terms of the GNU GPL License version 2
6 * Selftests for execveat(2).
9 #define _GNU_SOURCE /* to get O_PATH, AT_EMPTY_PATH */
10 #include <sys/sendfile.h>
12 #include <sys/syscall.h>
13 #include <sys/types.h>
23 static char longpath[2 * PATH_MAX] = "";
24 static char *envp[] = { "IN_TEST=yes", NULL, NULL };
25 static char *argv[] = { "execveat", "99", NULL };
27 static int execveat_(int fd, const char *path, char **argv, char **envp,
31 return syscall(__NR_execveat, fd, path, argv, envp, flags);
38 #define check_execveat_fail(fd, path, flags, errno) \
39 _check_execveat_fail(fd, path, flags, errno, #errno)
40 static int _check_execveat_fail(int fd, const char *path, int flags,
41 int expected_errno, const char *errno_str)
46 printf("Check failure of execveat(%d, '%s', %d) with %s... ",
47 fd, path?:"(null)", flags, errno_str);
48 rc = execveat_(fd, path, argv, envp, flags);
51 printf("[FAIL] (unexpected success from execveat(2))\n");
54 if (errno != expected_errno) {
55 printf("[FAIL] (expected errno %d (%s) not %d (%s)\n",
56 expected_errno, strerror(expected_errno),
57 errno, strerror(errno));
64 static int check_execveat_invoked_rc(int fd, const char *path, int flags,
65 int expected_rc, int expected_rc2)
70 int pathlen = path ? strlen(path) : 0;
73 printf("Check success of execveat(%d, '%.20s...%s', %d)... ",
74 fd, path, (path + pathlen - 20), flags);
76 printf("Check success of execveat(%d, '%s', %d)... ",
77 fd, path?:"(null)", flags);
80 printf("[FAIL] (fork() failed)\n");
84 /* Child: do execveat(). */
85 rc = execveat_(fd, path, argv, envp, flags);
86 printf("[FAIL]: execveat() failed, rc=%d errno=%d (%s)\n",
87 rc, errno, strerror(errno));
88 exit(1); /* should not reach here */
90 /* Parent: wait for & check child's exit status. */
91 rc = waitpid(child, &status, 0);
93 printf("[FAIL] (waitpid(%d,...) returned %d)\n", child, rc);
96 if (!WIFEXITED(status)) {
97 printf("[FAIL] (child %d did not exit cleanly, status=%08x)\n",
101 if ((WEXITSTATUS(status) != expected_rc) &&
102 (WEXITSTATUS(status) != expected_rc2)) {
103 printf("[FAIL] (child %d exited with %d not %d nor %d)\n",
104 child, WEXITSTATUS(status), expected_rc, expected_rc2);
111 static int check_execveat(int fd, const char *path, int flags)
113 return check_execveat_invoked_rc(fd, path, flags, 99, 99);
116 static char *concat(const char *left, const char *right)
118 char *result = malloc(strlen(left) + strlen(right) + 1);
120 strcpy(result, left);
121 strcat(result, right);
125 static int open_or_die(const char *filename, int flags)
127 int fd = open(filename, flags);
130 printf("Failed to open '%s'; "
131 "check prerequisites are available\n", filename);
137 static void exe_cp(const char *src, const char *dest)
139 int in_fd = open_or_die(src, O_RDONLY);
140 int out_fd = open(dest, O_RDWR|O_CREAT|O_TRUNC, 0755);
144 sendfile(out_fd, in_fd, NULL, info.st_size);
149 #define XX_DIR_LEN 200
150 static int check_execveat_pathmax(int dot_dfd, const char *src, int is_script)
154 char longname[XX_DIR_LEN + 1];
157 if (*longpath == '\0') {
158 /* Create a filename close to PATH_MAX in length */
159 memset(longname, 'x', XX_DIR_LEN - 1);
160 longname[XX_DIR_LEN - 1] = '/';
161 longname[XX_DIR_LEN] = '\0';
162 count = (PATH_MAX - 3) / XX_DIR_LEN;
163 for (ii = 0; ii < count; ii++) {
164 strcat(longpath, longname);
165 mkdir(longpath, 0755);
167 len = (PATH_MAX - 3) - (count * XX_DIR_LEN);
170 memset(longname, 'y', len);
171 longname[len] = '\0';
172 strcat(longpath, longname);
174 exe_cp(src, longpath);
177 * Execute as a pre-opened file descriptor, which works whether this is
178 * a script or not (because the interpreter sees a filename like
181 fd = open(longpath, O_RDONLY);
183 printf("Invoke copy of '%s' via filename of length %zu:\n",
184 src, strlen(longpath));
185 fail += check_execveat(fd, "", AT_EMPTY_PATH);
187 printf("Failed to open length %zu filename, errno=%d (%s)\n",
188 strlen(longpath), errno, strerror(errno));
193 * Execute as a long pathname relative to ".". If this is a script,
194 * the interpreter will launch but fail to open the script because its
195 * name ("/dev/fd/5/xxx....") is bigger than PATH_MAX.
197 * The failure code is usually 127 (POSIX: "If a command is not found,
198 * the exit status shall be 127."), but some systems give 126 (POSIX:
199 * "If the command name is found, but it is not an executable utility,
200 * the exit status shall be 126."), so allow either.
203 fail += check_execveat_invoked_rc(dot_dfd, longpath, 0,
206 fail += check_execveat(dot_dfd, longpath, 0);
211 static int run_tests(void)
214 char *fullname = realpath("execveat", NULL);
215 char *fullname_script = realpath("script", NULL);
216 char *fullname_symlink = concat(fullname, ".symlink");
217 int subdir_dfd = open_or_die("subdir", O_DIRECTORY|O_RDONLY);
218 int subdir_dfd_ephemeral = open_or_die("subdir.ephemeral",
219 O_DIRECTORY|O_RDONLY);
220 int dot_dfd = open_or_die(".", O_DIRECTORY|O_RDONLY);
221 int dot_dfd_path = open_or_die(".", O_DIRECTORY|O_RDONLY|O_PATH);
222 int dot_dfd_cloexec = open_or_die(".", O_DIRECTORY|O_RDONLY|O_CLOEXEC);
223 int fd = open_or_die("execveat", O_RDONLY);
224 int fd_path = open_or_die("execveat", O_RDONLY|O_PATH);
225 int fd_symlink = open_or_die("execveat.symlink", O_RDONLY);
226 int fd_denatured = open_or_die("execveat.denatured", O_RDONLY);
227 int fd_denatured_path = open_or_die("execveat.denatured",
229 int fd_script = open_or_die("script", O_RDONLY);
230 int fd_ephemeral = open_or_die("execveat.ephemeral", O_RDONLY);
231 int fd_ephemeral_path = open_or_die("execveat.path.ephemeral",
233 int fd_script_ephemeral = open_or_die("script.ephemeral", O_RDONLY);
234 int fd_cloexec = open_or_die("execveat", O_RDONLY|O_CLOEXEC);
235 int fd_script_cloexec = open_or_die("script", O_RDONLY|O_CLOEXEC);
237 /* Check if we have execveat at all, and bail early if not */
239 execveat_(-1, NULL, NULL, NULL, 0);
240 if (errno == ENOSYS) {
241 printf("[FAIL] ENOSYS calling execveat - no kernel support?\n");
245 /* Change file position to confirm it doesn't affect anything */
246 lseek(fd, 10, SEEK_SET);
248 /* Normal executable file: */
250 fail += check_execveat(subdir_dfd, "../execveat", 0);
251 fail += check_execveat(dot_dfd, "execveat", 0);
252 fail += check_execveat(dot_dfd_path, "execveat", 0);
254 fail += check_execveat(AT_FDCWD, fullname, 0);
255 /* absolute path with nonsense dfd */
256 fail += check_execveat(99, fullname, 0);
258 fail += check_execveat(fd, "", AT_EMPTY_PATH);
259 /* O_CLOEXEC fd + no path */
260 fail += check_execveat(fd_cloexec, "", AT_EMPTY_PATH);
262 fail += check_execveat(fd_path, "", AT_EMPTY_PATH);
264 /* Mess with executable file that's already open: */
265 /* fd + no path to a file that's been renamed */
266 rename("execveat.ephemeral", "execveat.moved");
267 fail += check_execveat(fd_ephemeral, "", AT_EMPTY_PATH);
268 /* fd + no path to a file that's been deleted */
269 unlink("execveat.moved"); /* remove the file now fd open */
270 fail += check_execveat(fd_ephemeral, "", AT_EMPTY_PATH);
272 /* Mess with executable file that's already open with O_PATH */
273 /* fd + no path to a file that's been deleted */
274 unlink("execveat.path.ephemeral");
275 fail += check_execveat(fd_ephemeral_path, "", AT_EMPTY_PATH);
277 /* Invalid argument failures */
278 fail += check_execveat_fail(fd, "", 0, ENOENT);
279 fail += check_execveat_fail(fd, NULL, AT_EMPTY_PATH, EFAULT);
281 /* Symlink to executable file: */
283 fail += check_execveat(dot_dfd, "execveat.symlink", 0);
284 fail += check_execveat(dot_dfd_path, "execveat.symlink", 0);
286 fail += check_execveat(AT_FDCWD, fullname_symlink, 0);
287 /* fd + no path, even with AT_SYMLINK_NOFOLLOW (already followed) */
288 fail += check_execveat(fd_symlink, "", AT_EMPTY_PATH);
289 fail += check_execveat(fd_symlink, "",
290 AT_EMPTY_PATH|AT_SYMLINK_NOFOLLOW);
292 /* Symlink fails when AT_SYMLINK_NOFOLLOW set: */
294 fail += check_execveat_fail(dot_dfd, "execveat.symlink",
295 AT_SYMLINK_NOFOLLOW, ELOOP);
296 fail += check_execveat_fail(dot_dfd_path, "execveat.symlink",
297 AT_SYMLINK_NOFOLLOW, ELOOP);
299 fail += check_execveat_fail(AT_FDCWD, fullname_symlink,
300 AT_SYMLINK_NOFOLLOW, ELOOP);
302 /* Shell script wrapping executable file: */
304 fail += check_execveat(subdir_dfd, "../script", 0);
305 fail += check_execveat(dot_dfd, "script", 0);
306 fail += check_execveat(dot_dfd_path, "script", 0);
308 fail += check_execveat(AT_FDCWD, fullname_script, 0);
310 fail += check_execveat(fd_script, "", AT_EMPTY_PATH);
311 fail += check_execveat(fd_script, "",
312 AT_EMPTY_PATH|AT_SYMLINK_NOFOLLOW);
313 /* O_CLOEXEC fd fails for a script (as script file inaccessible) */
314 fail += check_execveat_fail(fd_script_cloexec, "", AT_EMPTY_PATH,
316 fail += check_execveat_fail(dot_dfd_cloexec, "script", 0, ENOENT);
318 /* Mess with script file that's already open: */
319 /* fd + no path to a file that's been renamed */
320 rename("script.ephemeral", "script.moved");
321 fail += check_execveat(fd_script_ephemeral, "", AT_EMPTY_PATH);
322 /* fd + no path to a file that's been deleted */
323 unlink("script.moved"); /* remove the file while fd open */
324 fail += check_execveat(fd_script_ephemeral, "", AT_EMPTY_PATH);
326 /* Rename a subdirectory in the path: */
327 rename("subdir.ephemeral", "subdir.moved");
328 fail += check_execveat(subdir_dfd_ephemeral, "../script", 0);
329 fail += check_execveat(subdir_dfd_ephemeral, "script", 0);
330 /* Remove the subdir and its contents */
331 unlink("subdir.moved/script");
332 unlink("subdir.moved");
333 /* Shell loads via deleted subdir OK because name starts with .. */
334 fail += check_execveat(subdir_dfd_ephemeral, "../script", 0);
335 fail += check_execveat_fail(subdir_dfd_ephemeral, "script", 0, ENOENT);
337 /* Flag values other than AT_SYMLINK_NOFOLLOW => EINVAL */
338 fail += check_execveat_fail(dot_dfd, "execveat", 0xFFFF, EINVAL);
339 /* Invalid path => ENOENT */
340 fail += check_execveat_fail(dot_dfd, "no-such-file", 0, ENOENT);
341 fail += check_execveat_fail(dot_dfd_path, "no-such-file", 0, ENOENT);
342 fail += check_execveat_fail(AT_FDCWD, "no-such-file", 0, ENOENT);
343 /* Attempt to execute directory => EACCES */
344 fail += check_execveat_fail(dot_dfd, "", AT_EMPTY_PATH, EACCES);
345 /* Attempt to execute non-executable => EACCES */
346 fail += check_execveat_fail(dot_dfd, "Makefile", 0, EACCES);
347 fail += check_execveat_fail(fd_denatured, "", AT_EMPTY_PATH, EACCES);
348 fail += check_execveat_fail(fd_denatured_path, "", AT_EMPTY_PATH,
350 /* Attempt to execute nonsense FD => EBADF */
351 fail += check_execveat_fail(99, "", AT_EMPTY_PATH, EBADF);
352 fail += check_execveat_fail(99, "execveat", 0, EBADF);
353 /* Attempt to execute relative to non-directory => ENOTDIR */
354 fail += check_execveat_fail(fd, "execveat", 0, ENOTDIR);
356 fail += check_execveat_pathmax(dot_dfd, "execveat", 0);
357 fail += check_execveat_pathmax(dot_dfd, "script", 1);
361 static void prerequisites(void)
364 const char *script = "#!/bin/sh\nexit $*\n";
366 /* Create ephemeral copies of files */
367 exe_cp("execveat", "execveat.ephemeral");
368 exe_cp("execveat", "execveat.path.ephemeral");
369 exe_cp("script", "script.ephemeral");
370 mkdir("subdir.ephemeral", 0755);
372 fd = open("subdir.ephemeral/script", O_RDWR|O_CREAT|O_TRUNC, 0755);
373 write(fd, script, strlen(script));
377 int main(int argc, char **argv)
381 const char *verbose = getenv("VERBOSE");
384 /* If we are invoked with an argument, don't run tests. */
385 const char *in_test = getenv("IN_TEST");
388 printf(" invoked with:");
389 for (ii = 0; ii < argc; ii++)
390 printf(" [%d]='%s'", ii, argv[ii]);
394 /* Check expected environment transferred. */
395 if (!in_test || strcmp(in_test, "yes") != 0) {
396 printf("[FAIL] (no IN_TEST=yes in env)\n");
400 /* Use the final argument as an exit code. */
401 rc = atoi(argv[argc - 1]);
406 envp[1] = "VERBOSE=1";
409 printf("%d tests failed\n", rc);