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-rw-r--r--tools/testing/selftests/exec/execveat.c397
1 files changed, 397 insertions, 0 deletions
diff --git a/tools/testing/selftests/exec/execveat.c b/tools/testing/selftests/exec/execveat.c
new file mode 100644
index 000000000000..33a5c06d95ca
--- /dev/null
+++ b/tools/testing/selftests/exec/execveat.c
@@ -0,0 +1,397 @@
1/*
2 * Copyright (c) 2014 Google, Inc.
3 *
4 * Licensed under the terms of the GNU GPL License version 2
5 *
6 * Selftests for execveat(2).
7 */
8
9#define _GNU_SOURCE /* to get O_PATH, AT_EMPTY_PATH */
10#include <sys/sendfile.h>
11#include <sys/stat.h>
12#include <sys/syscall.h>
13#include <sys/types.h>
14#include <sys/wait.h>
15#include <errno.h>
16#include <fcntl.h>
17#include <limits.h>
18#include <stdio.h>
19#include <stdlib.h>
20#include <string.h>
21#include <unistd.h>
22
23static char longpath[2 * PATH_MAX] = "";
24static char *envp[] = { "IN_TEST=yes", NULL, NULL };
25static char *argv[] = { "execveat", "99", NULL };
26
27static int execveat_(int fd, const char *path, char **argv, char **envp,
28 int flags)
29{
30#ifdef __NR_execveat
31 return syscall(__NR_execveat, fd, path, argv, envp, flags);
32#else
33 errno = -ENOSYS;
34 return -1;
35#endif
36}
37
38#define check_execveat_fail(fd, path, flags, errno) \
39 _check_execveat_fail(fd, path, flags, errno, #errno)
40static int _check_execveat_fail(int fd, const char *path, int flags,
41 int expected_errno, const char *errno_str)
42{
43 int rc;
44
45 errno = 0;
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);
49
50 if (rc > 0) {
51 printf("[FAIL] (unexpected success from execveat(2))\n");
52 return 1;
53 }
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));
58 return 1;
59 }
60 printf("[OK]\n");
61 return 0;
62}
63
64static int check_execveat_invoked_rc(int fd, const char *path, int flags,
65 int expected_rc)
66{
67 int status;
68 int rc;
69 pid_t child;
70 int pathlen = path ? strlen(path) : 0;
71
72 if (pathlen > 40)
73 printf("Check success of execveat(%d, '%.20s...%s', %d)... ",
74 fd, path, (path + pathlen - 20), flags);
75 else
76 printf("Check success of execveat(%d, '%s', %d)... ",
77 fd, path?:"(null)", flags);
78 child = fork();
79 if (child < 0) {
80 printf("[FAIL] (fork() failed)\n");
81 return 1;
82 }
83 if (child == 0) {
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 */
89 }
90 /* Parent: wait for & check child's exit status. */
91 rc = waitpid(child, &status, 0);
92 if (rc != child) {
93 printf("[FAIL] (waitpid(%d,...) returned %d)\n", child, rc);
94 return 1;
95 }
96 if (!WIFEXITED(status)) {
97 printf("[FAIL] (child %d did not exit cleanly, status=%08x)\n",
98 child, status);
99 return 1;
100 }
101 if (WEXITSTATUS(status) != expected_rc) {
102 printf("[FAIL] (child %d exited with %d not %d)\n",
103 child, WEXITSTATUS(status), expected_rc);
104 return 1;
105 }
106 printf("[OK]\n");
107 return 0;
108}
109
110static int check_execveat(int fd, const char *path, int flags)
111{
112 return check_execveat_invoked_rc(fd, path, flags, 99);
113}
114
115static char *concat(const char *left, const char *right)
116{
117 char *result = malloc(strlen(left) + strlen(right) + 1);
118
119 strcpy(result, left);
120 strcat(result, right);
121 return result;
122}
123
124static int open_or_die(const char *filename, int flags)
125{
126 int fd = open(filename, flags);
127
128 if (fd < 0) {
129 printf("Failed to open '%s'; "
130 "check prerequisites are available\n", filename);
131 exit(1);
132 }
133 return fd;
134}
135
136static void exe_cp(const char *src, const char *dest)
137{
138 int in_fd = open_or_die(src, O_RDONLY);
139 int out_fd = open(dest, O_RDWR|O_CREAT|O_TRUNC, 0755);
140 struct stat info;
141
142 fstat(in_fd, &info);
143 sendfile(out_fd, in_fd, NULL, info.st_size);
144 close(in_fd);
145 close(out_fd);
146}
147
148#define XX_DIR_LEN 200
149static int check_execveat_pathmax(int dot_dfd, const char *src, int is_script)
150{
151 int fail = 0;
152 int ii, count, len;
153 char longname[XX_DIR_LEN + 1];
154 int fd;
155
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);
165 }
166 len = (PATH_MAX - 3) - (count * XX_DIR_LEN);
167 if (len <= 0)
168 len = 1;
169 memset(longname, 'y', len);
170 longname[len] = '\0';
171 strcat(longpath, longname);
172 }
173 exe_cp(src, longpath);
174
175 /*
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
178 * "/dev/fd/20").
179 */
180 fd = open(longpath, O_RDONLY);
181 if (fd > 0) {
182 printf("Invoke copy of '%s' via filename of length %lu:\n",
183 src, strlen(longpath));
184 fail += check_execveat(fd, "", AT_EMPTY_PATH);
185 } else {
186 printf("Failed to open length %lu filename, errno=%d (%s)\n",
187 strlen(longpath), errno, strerror(errno));
188 fail++;
189 }
190
191 /*
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.
195 */
196 if (is_script)
197 fail += check_execveat_invoked_rc(dot_dfd, longpath, 0, 127);
198 else
199 fail += check_execveat(dot_dfd, longpath, 0);
200
201 return fail;
202}
203
204static int run_tests(void)
205{
206 int fail = 0;
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",
221 O_RDONLY|O_PATH);
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",
225 O_RDONLY|O_PATH);
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);
229
230 /* Change file position to confirm it doesn't affect anything */
231 lseek(fd, 10, SEEK_SET);
232
233 /* Normal executable file: */
234 /* dfd + path */
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);
238 /* absolute path */
239 fail += check_execveat(AT_FDCWD, fullname, 0);
240 /* absolute path with nonsense dfd */
241 fail += check_execveat(99, fullname, 0);
242 /* fd + no path */
243 fail += check_execveat(fd, "", AT_EMPTY_PATH);
244 /* O_CLOEXEC fd + no path */
245 fail += check_execveat(fd_cloexec, "", AT_EMPTY_PATH);
246 /* O_PATH fd */
247 fail += check_execveat(fd_path, "", AT_EMPTY_PATH);
248
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);
256
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);
261
262 /* Invalid argument failures */
263 fail += check_execveat_fail(fd, "", 0, ENOENT);
264 fail += check_execveat_fail(fd, NULL, AT_EMPTY_PATH, EFAULT);
265
266 /* Symlink to executable file: */
267 /* dfd + path */
268 fail += check_execveat(dot_dfd, "execveat.symlink", 0);
269 fail += check_execveat(dot_dfd_path, "execveat.symlink", 0);
270 /* absolute path */
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);
276
277 /* Symlink fails when AT_SYMLINK_NOFOLLOW set: */
278 /* dfd + path */
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);
283 /* absolute path */
284 fail += check_execveat_fail(AT_FDCWD, fullname_symlink,
285 AT_SYMLINK_NOFOLLOW, ELOOP);
286
287 /* Shell script wrapping executable file: */
288 /* dfd + path */
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);
292 /* absolute path */
293 fail += check_execveat(AT_FDCWD, fullname_script, 0);
294 /* fd + no path */
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,
300 ENOENT);
301 fail += check_execveat_fail(dot_dfd_cloexec, "script", 0, ENOENT);
302
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);
310
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);
321
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,
334 EACCES);
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);
340
341 fail += check_execveat_pathmax(dot_dfd, "execveat", 0);
342 fail += check_execveat_pathmax(dot_dfd, "script", 1);
343 return fail;
344}
345
346static void prerequisites(void)
347{
348 int fd;
349 const char *script = "#!/bin/sh\nexit $*\n";
350
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);
356
357 fd = open("subdir.ephemeral/script", O_RDWR|O_CREAT|O_TRUNC, 0755);
358 write(fd, script, strlen(script));
359 close(fd);
360}
361
362int main(int argc, char **argv)
363{
364 int ii;
365 int rc;
366 const char *verbose = getenv("VERBOSE");
367
368 if (argc >= 2) {
369 /* If we are invoked with an argument, don't run tests. */
370 const char *in_test = getenv("IN_TEST");
371
372 if (verbose) {
373 printf(" invoked with:");
374 for (ii = 0; ii < argc; ii++)
375 printf(" [%d]='%s'", ii, argv[ii]);
376 printf("\n");
377 }
378
379 /* Check expected environment transferred. */
380 if (!in_test || strcmp(in_test, "yes") != 0) {
381 printf("[FAIL] (no IN_TEST=yes in env)\n");
382 return 1;
383 }
384
385 /* Use the final argument as an exit code. */
386 rc = atoi(argv[argc - 1]);
387 fflush(stdout);
388 } else {
389 prerequisites();
390 if (verbose)
391 envp[1] = "VERBOSE=1";
392 rc = run_tests();
393 if (rc > 0)
394 printf("%d tests failed\n", rc);
395 }
396 return rc;
397}
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