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,
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 printf("[FAIL] (child %d exited with %d not %d)\n",
103 child, WEXITSTATUS(status), expected_rc);
110 static int check_execveat(int fd, const char *path, int flags)
112 return check_execveat_invoked_rc(fd, path, flags, 99);
115 static char *concat(const char *left, const char *right)
117 char *result = malloc(strlen(left) + strlen(right) + 1);
119 strcpy(result, left);
120 strcat(result, right);
124 static int open_or_die(const char *filename, int flags)
126 int fd = open(filename, flags);
129 printf("Failed to open '%s'; "
130 "check prerequisites are available\n", filename);
136 static void exe_cp(const char *src, const char *dest)
138 int in_fd = open_or_die(src, O_RDONLY);
139 int out_fd = open(dest, O_RDWR|O_CREAT|O_TRUNC, 0755);
143 sendfile(out_fd, in_fd, NULL, info.st_size);
148 #define XX_DIR_LEN 200
149 static int check_execveat_pathmax(int dot_dfd, const char *src, int is_script)
153 char longname[XX_DIR_LEN + 1];
156 if (*longpath == '\0') {
157 /* Create a filename close to PATH_MAX in length */
158 memset(longname, 'x', XX_DIR_LEN - 1);
159 longname[XX_DIR_LEN - 1] = '/';
160 longname[XX_DIR_LEN] = '\0';
161 count = (PATH_MAX - 3) / XX_DIR_LEN;
162 for (ii = 0; ii < count; ii++) {
163 strcat(longpath, longname);
164 mkdir(longpath, 0755);
166 len = (PATH_MAX - 3) - (count * XX_DIR_LEN);
169 memset(longname, 'y', len);
170 longname[len] = '\0';
171 strcat(longpath, longname);
173 exe_cp(src, longpath);
176 * Execute as a pre-opened file descriptor, which works whether this is
177 * a script or not (because the interpreter sees a filename like
180 fd = open(longpath, O_RDONLY);
182 printf("Invoke copy of '%s' via filename of length %zu:\n",
183 src, strlen(longpath));
184 fail += check_execveat(fd, "", AT_EMPTY_PATH);
186 printf("Failed to open length %zu filename, errno=%d (%s)\n",
187 strlen(longpath), errno, strerror(errno));
192 * Execute as a long pathname relative to ".". If this is a script,
193 * the interpreter will launch but fail to open the script because its
194 * name ("/dev/fd/5/xxx....") is bigger than PATH_MAX.
197 fail += check_execveat_invoked_rc(dot_dfd, longpath, 0, 127);
199 fail += check_execveat(dot_dfd, longpath, 0);
204 static int run_tests(void)
207 char *fullname = realpath("execveat", NULL);
208 char *fullname_script = realpath("script", NULL);
209 char *fullname_symlink = concat(fullname, ".symlink");
210 int subdir_dfd = open_or_die("subdir", O_DIRECTORY|O_RDONLY);
211 int subdir_dfd_ephemeral = open_or_die("subdir.ephemeral",
212 O_DIRECTORY|O_RDONLY);
213 int dot_dfd = open_or_die(".", O_DIRECTORY|O_RDONLY);
214 int dot_dfd_path = open_or_die(".", O_DIRECTORY|O_RDONLY|O_PATH);
215 int dot_dfd_cloexec = open_or_die(".", O_DIRECTORY|O_RDONLY|O_CLOEXEC);
216 int fd = open_or_die("execveat", O_RDONLY);
217 int fd_path = open_or_die("execveat", O_RDONLY|O_PATH);
218 int fd_symlink = open_or_die("execveat.symlink", O_RDONLY);
219 int fd_denatured = open_or_die("execveat.denatured", O_RDONLY);
220 int fd_denatured_path = open_or_die("execveat.denatured",
222 int fd_script = open_or_die("script", O_RDONLY);
223 int fd_ephemeral = open_or_die("execveat.ephemeral", O_RDONLY);
224 int fd_ephemeral_path = open_or_die("execveat.path.ephemeral",
226 int fd_script_ephemeral = open_or_die("script.ephemeral", O_RDONLY);
227 int fd_cloexec = open_or_die("execveat", O_RDONLY|O_CLOEXEC);
228 int fd_script_cloexec = open_or_die("script", O_RDONLY|O_CLOEXEC);
230 /* Change file position to confirm it doesn't affect anything */
231 lseek(fd, 10, SEEK_SET);
233 /* Normal executable file: */
235 fail += check_execveat(subdir_dfd, "../execveat", 0);
236 fail += check_execveat(dot_dfd, "execveat", 0);
237 fail += check_execveat(dot_dfd_path, "execveat", 0);
239 fail += check_execveat(AT_FDCWD, fullname, 0);
240 /* absolute path with nonsense dfd */
241 fail += check_execveat(99, fullname, 0);
243 fail += check_execveat(fd, "", AT_EMPTY_PATH);
244 /* O_CLOEXEC fd + no path */
245 fail += check_execveat(fd_cloexec, "", AT_EMPTY_PATH);
247 fail += check_execveat(fd_path, "", AT_EMPTY_PATH);
249 /* Mess with executable file that's already open: */
250 /* fd + no path to a file that's been renamed */
251 rename("execveat.ephemeral", "execveat.moved");
252 fail += check_execveat(fd_ephemeral, "", AT_EMPTY_PATH);
253 /* fd + no path to a file that's been deleted */
254 unlink("execveat.moved"); /* remove the file now fd open */
255 fail += check_execveat(fd_ephemeral, "", AT_EMPTY_PATH);
257 /* Mess with executable file that's already open with O_PATH */
258 /* fd + no path to a file that's been deleted */
259 unlink("execveat.path.ephemeral");
260 fail += check_execveat(fd_ephemeral_path, "", AT_EMPTY_PATH);
262 /* Invalid argument failures */
263 fail += check_execveat_fail(fd, "", 0, ENOENT);
264 fail += check_execveat_fail(fd, NULL, AT_EMPTY_PATH, EFAULT);
266 /* Symlink to executable file: */
268 fail += check_execveat(dot_dfd, "execveat.symlink", 0);
269 fail += check_execveat(dot_dfd_path, "execveat.symlink", 0);
271 fail += check_execveat(AT_FDCWD, fullname_symlink, 0);
272 /* fd + no path, even with AT_SYMLINK_NOFOLLOW (already followed) */
273 fail += check_execveat(fd_symlink, "", AT_EMPTY_PATH);
274 fail += check_execveat(fd_symlink, "",
275 AT_EMPTY_PATH|AT_SYMLINK_NOFOLLOW);
277 /* Symlink fails when AT_SYMLINK_NOFOLLOW set: */
279 fail += check_execveat_fail(dot_dfd, "execveat.symlink",
280 AT_SYMLINK_NOFOLLOW, ELOOP);
281 fail += check_execveat_fail(dot_dfd_path, "execveat.symlink",
282 AT_SYMLINK_NOFOLLOW, ELOOP);
284 fail += check_execveat_fail(AT_FDCWD, fullname_symlink,
285 AT_SYMLINK_NOFOLLOW, ELOOP);
287 /* Shell script wrapping executable file: */
289 fail += check_execveat(subdir_dfd, "../script", 0);
290 fail += check_execveat(dot_dfd, "script", 0);
291 fail += check_execveat(dot_dfd_path, "script", 0);
293 fail += check_execveat(AT_FDCWD, fullname_script, 0);
295 fail += check_execveat(fd_script, "", AT_EMPTY_PATH);
296 fail += check_execveat(fd_script, "",
297 AT_EMPTY_PATH|AT_SYMLINK_NOFOLLOW);
298 /* O_CLOEXEC fd fails for a script (as script file inaccessible) */
299 fail += check_execveat_fail(fd_script_cloexec, "", AT_EMPTY_PATH,
301 fail += check_execveat_fail(dot_dfd_cloexec, "script", 0, ENOENT);
303 /* Mess with script file that's already open: */
304 /* fd + no path to a file that's been renamed */
305 rename("script.ephemeral", "script.moved");
306 fail += check_execveat(fd_script_ephemeral, "", AT_EMPTY_PATH);
307 /* fd + no path to a file that's been deleted */
308 unlink("script.moved"); /* remove the file while fd open */
309 fail += check_execveat(fd_script_ephemeral, "", AT_EMPTY_PATH);
311 /* Rename a subdirectory in the path: */
312 rename("subdir.ephemeral", "subdir.moved");
313 fail += check_execveat(subdir_dfd_ephemeral, "../script", 0);
314 fail += check_execveat(subdir_dfd_ephemeral, "script", 0);
315 /* Remove the subdir and its contents */
316 unlink("subdir.moved/script");
317 unlink("subdir.moved");
318 /* Shell loads via deleted subdir OK because name starts with .. */
319 fail += check_execveat(subdir_dfd_ephemeral, "../script", 0);
320 fail += check_execveat_fail(subdir_dfd_ephemeral, "script", 0, ENOENT);
322 /* Flag values other than AT_SYMLINK_NOFOLLOW => EINVAL */
323 fail += check_execveat_fail(dot_dfd, "execveat", 0xFFFF, EINVAL);
324 /* Invalid path => ENOENT */
325 fail += check_execveat_fail(dot_dfd, "no-such-file", 0, ENOENT);
326 fail += check_execveat_fail(dot_dfd_path, "no-such-file", 0, ENOENT);
327 fail += check_execveat_fail(AT_FDCWD, "no-such-file", 0, ENOENT);
328 /* Attempt to execute directory => EACCES */
329 fail += check_execveat_fail(dot_dfd, "", AT_EMPTY_PATH, EACCES);
330 /* Attempt to execute non-executable => EACCES */
331 fail += check_execveat_fail(dot_dfd, "Makefile", 0, EACCES);
332 fail += check_execveat_fail(fd_denatured, "", AT_EMPTY_PATH, EACCES);
333 fail += check_execveat_fail(fd_denatured_path, "", AT_EMPTY_PATH,
335 /* Attempt to execute nonsense FD => EBADF */
336 fail += check_execveat_fail(99, "", AT_EMPTY_PATH, EBADF);
337 fail += check_execveat_fail(99, "execveat", 0, EBADF);
338 /* Attempt to execute relative to non-directory => ENOTDIR */
339 fail += check_execveat_fail(fd, "execveat", 0, ENOTDIR);
341 fail += check_execveat_pathmax(dot_dfd, "execveat", 0);
342 fail += check_execveat_pathmax(dot_dfd, "script", 1);
346 static void prerequisites(void)
349 const char *script = "#!/bin/sh\nexit $*\n";
351 /* Create ephemeral copies of files */
352 exe_cp("execveat", "execveat.ephemeral");
353 exe_cp("execveat", "execveat.path.ephemeral");
354 exe_cp("script", "script.ephemeral");
355 mkdir("subdir.ephemeral", 0755);
357 fd = open("subdir.ephemeral/script", O_RDWR|O_CREAT|O_TRUNC, 0755);
358 write(fd, script, strlen(script));
362 int main(int argc, char **argv)
366 const char *verbose = getenv("VERBOSE");
369 /* If we are invoked with an argument, don't run tests. */
370 const char *in_test = getenv("IN_TEST");
373 printf(" invoked with:");
374 for (ii = 0; ii < argc; ii++)
375 printf(" [%d]='%s'", ii, argv[ii]);
379 /* Check expected environment transferred. */
380 if (!in_test || strcmp(in_test, "yes") != 0) {
381 printf("[FAIL] (no IN_TEST=yes in env)\n");
385 /* Use the final argument as an exit code. */
386 rc = atoi(argv[argc - 1]);
391 envp[1] = "VERBOSE=1";
394 printf("%d tests failed\n", rc);