/[path-sandbox]/trunk/sandbox_futils.c
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Contents of /trunk/sandbox_futils.c

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Revision 101 - (show annotations) (download) (as text)
Fri May 13 15:23:28 2005 UTC (8 years, 11 months ago) by azarah
File MIME type: text/x-csrc
File size: 12971 byte(s)
General cleanups.

1 /*
2 * Copyright (C) 2002 Brad House <brad@mainstreetsoftworks.com>
3 * Distributed under the terms of the GNU General Public License, v2 or later
4 * Author: Brad House <brad@mainstreetsoftworks.com>
5 *
6 * $Header$
7 *
8 */
9
10 #include <errno.h>
11 #include <fcntl.h>
12 #include <signal.h>
13 #include <stdio.h>
14 #include <stdlib.h>
15 #include <limits.h>
16 #include <string.h>
17 #include <stdarg.h>
18 #include <sys/file.h>
19 #include <sys/stat.h>
20 #include <sys/time.h>
21 #include <sys/types.h>
22 #include <sys/resource.h>
23 #include <sys/wait.h>
24 #include <unistd.h>
25 #include <fcntl.h>
26
27 #include <grp.h>
28 #include <pwd.h>
29
30 #include "sandbox.h"
31 #include "config.h"
32
33 /* BEGIN Prototypes */
34 SB_STATIC int file_security_check(char *filename);
35 /* END Prototypes */
36
37 /* glibc modified getcwd() functions */
38 SB_STATIC char *egetcwd(char *, size_t);
39
40 SB_STATIC char *get_sandbox_path(char *argv0)
41 {
42 char path[SB_PATH_MAX];
43
44 memset(path, 0, sizeof(path));
45 /* ARGV[0] specifies full path */
46 if (argv0[0] == '/') {
47 strncpy(path, argv0, sizeof(path) - 1);
48
49 /* ARGV[0] specifies relative path */
50 } else {
51 if (-1 != readlink("/proc/self/exe", path, sizeof(path)))
52 path[sizeof(path) - 1] = '\0';
53 else
54 path[0] = '\0';
55 }
56
57 /* Return just directory */
58 return (sb_dirname(path));
59 }
60
61 SB_STATIC char *get_sandbox_lib(char *sb_path)
62 {
63 char path[SB_PATH_MAX];
64
65 #ifdef SB_HAVE_64BIT_ARCH
66 snprintf(path, sizeof(path), "%s", LIB_NAME);
67 #else
68 snprintf(path, sizeof(path), "%s/%s", LIBSANDBOX_PATH, LIB_NAME);
69 if (file_exist(path, 0) <= 0) {
70 snprintf(path, sizeof(path), "%s%s", sb_path, LIB_NAME);
71 }
72 #endif
73 return (strdup(path));
74 }
75
76 SB_STATIC char *get_sandbox_pids_file(const char *tmp_dir)
77 {
78 char path[SB_PATH_MAX];
79
80 if (0 < getenv("SANDBOX_PIDS_FILE")) {
81 return (strdup(getenv("SANDBOX_PIDS_FILE")));
82 }
83
84 snprintf(path, SB_PATH_MAX, "%s%s", tmp_dir, PIDS_FILE);
85 return (strdup(path));
86 }
87
88 SB_STATIC char *get_sandbox_rc(char *sb_path)
89 {
90 char path[SB_PATH_MAX];
91
92 snprintf(path, sizeof(path), "%s/%s", SANDBOX_BASHRC_PATH, BASHRC_NAME);
93 if (file_exist(path, 0) <= 0) {
94 snprintf(path, sizeof(path), "%s%s", sb_path, BASHRC_NAME);
95 }
96 return (strdup(path));
97 }
98
99 SB_STATIC char *get_sandbox_log(const char *tmp_dir)
100 {
101 char path[SB_PATH_MAX];
102 char *sandbox_log_env = NULL;
103
104 sandbox_log_env = getenv(ENV_SANDBOX_LOG);
105
106 /* THIS CHUNK BREAK THINGS BY DOING THIS:
107 * SANDBOX_LOG=/tmp/sandbox-app-admin/superadduser-1.0.7-11063.log
108 */
109 if ((NULL != sandbox_log_env) &&
110 (NULL != strchr(sandbox_log_env, '/')))
111 sandbox_log_env = NULL;
112
113 snprintf(path, sizeof(path) - 1, "%s%s%s%s%d%s",
114 tmp_dir, LOG_FILE_PREFIX,
115 (sandbox_log_env == NULL ? "" : sandbox_log_env),
116 (sandbox_log_env == NULL ? "" : "-"),
117 getpid(), LOG_FILE_EXT);
118 return (strdup(path));
119 }
120
121 SB_STATIC int get_tmp_dir(char *tmp_dir)
122 {
123 if (NULL == realpath(getenv(ENV_TMPDIR) ? getenv(ENV_TMPDIR)
124 : TMPDIR,
125 tmp_dir)) {
126 return -1;
127 }
128
129 return 0;
130 }
131
132 SB_STATIC char *get_sandbox_debug_log(const char *tmp_dir)
133 {
134 char path[SB_PATH_MAX];
135 char *sandbox_debug_log_env = NULL;
136
137 sandbox_debug_log_env = getenv(ENV_SANDBOX_DEBUG_LOG);
138
139 /* THIS CHUNK BREAK THINGS BY DOING THIS:
140 * SANDBOX_DEBUG_LOG=/tmp/sandbox-app-admin/superadduser-1.0.7-11063.log
141 */
142 if ((NULL != sandbox_debug_log_env) &&
143 (NULL != strchr(sandbox_debug_log_env, '/')))
144 sandbox_debug_log_env = NULL;
145
146 snprintf(path, sizeof(path) - 1, "%s%s%s%s%d%s",
147 tmp_dir, DEBUG_LOG_FILE_PREFIX,
148 (sandbox_debug_log_env == NULL ? "" : sandbox_debug_log_env),
149 (sandbox_debug_log_env == NULL ? "" : "-"),
150 getpid(), LOG_FILE_EXT);
151 return (strdup(path));
152 }
153
154 /* Obtain base directory name. Do not allow trailing / */
155 SB_STATIC char *sb_dirname(const char *path)
156 {
157 char *ret = NULL;
158 char *ptr = NULL;
159 int loc = 0, i;
160 int cut_len = -1;
161
162 /* don't think NULL will ever be passed, but just in case */
163 if (NULL == path)
164 return (strdup("."));
165
166 /* Grab pointer to last slash */
167 ptr = strrchr(path, '/');
168 if (NULL == ptr) {
169 return (strdup("."));
170 }
171
172 /* decimal location of pointer */
173 loc = ptr - path;
174
175 /* Remove any trailing slash */
176 for (i = loc - 1; i >= 0; i--) {
177 if (path[i] != '/') {
178 cut_len = i + 1; /* make cut_len the length of the string to keep */
179 break;
180 }
181 }
182
183 /* It could have been just a plain /, return a 1byte 0 filled string */
184 if (-1 == cut_len)
185 return (strdup(""));
186
187 /* Allocate memory, and return the directory */
188 ret = (char *)malloc((cut_len + 1) * sizeof(char));
189 memcpy(ret, path, cut_len);
190 ret[cut_len] = 0;
191
192 return (ret);
193 }
194
195 /*
196 SB_STATIC char* dirname(const char* path)
197 {
198 char* base = NULL;
199 unsigned int length = 0;
200
201 base = strrchr(path, '/');
202 if (NULL == base)
203 {
204 return strdup(".");
205 }
206 while (base > path && *base == '/')
207 {
208 base--;
209 }
210 length = (unsigned int) 1 + base - path;
211
212 base = malloc(sizeof(char)*(length+1));
213 memmove(base, path, length);
214 base[length] = 0;
215
216 return base;
217 }*/
218
219 /* Convert text (string) modes to integer values */
220 SB_STATIC int file_getmode(char *mode)
221 {
222 int mde = 0;
223 if (0 == strcasecmp(mode, "r+")) {
224 mde = O_RDWR | O_CREAT;
225 } else if (0 == strcasecmp(mode, "w+")) {
226 mde = O_RDWR | O_CREAT | O_TRUNC;
227 } else if (0 == strcasecmp(mode, "a+")) {
228 mde = O_RDWR | O_CREAT | O_APPEND;
229 } else if (0 == strcasecmp(mode, "r")) {
230 mde = O_RDONLY;
231 } else if (0 == strcasecmp(mode, "w")) {
232 mde = O_WRONLY | O_CREAT | O_TRUNC;
233 } else if (0 == strcasecmp(mode, "a")) {
234 mde = O_WRONLY | O_APPEND | O_CREAT;
235 } else {
236 mde = O_RDONLY;
237 }
238 return (mde);
239 }
240
241 /* Get current position in file */
242 SB_STATIC long file_tell(int fp)
243 {
244 return (lseek(fp, 0L, SEEK_CUR));
245 }
246
247 /* lock the file, preferrably the POSIX way */
248 SB_STATIC int file_lock(int fd, int lock, char *filename)
249 {
250 int err;
251 #ifdef USE_FLOCK
252 if (flock(fd, lock) < 0) {
253 err = errno;
254 fprintf(stderr, ">>> %s flock file lock: %s\n", filename, strerror(err));
255 return 0;
256 }
257 #else
258 struct flock fl;
259 fl.l_type = lock;
260 fl.l_whence = SEEK_SET;
261 fl.l_start = 0L;
262 fl.l_len = 0L;
263 fl.l_pid = getpid();
264 if (fcntl(fd, F_SETLKW, &fl) < 0) {
265 err = errno;
266 fprintf(stderr, ">>> %s fcntl file lock: %s\n", filename, strerror(err));
267 return 0;
268 }
269 #endif
270 return 1;
271 }
272
273 /* unlock the file, preferrably the POSIX way */
274 SB_STATIC int file_unlock(int fd)
275 {
276 #ifdef USE_FLOCK
277 if (flock(fd, LOCK_UN) < 0) {
278 perror(">>> flock file unlock");
279 return 0;
280 }
281 #else
282 struct flock fl;
283 fl.l_type = F_UNLCK;
284 fl.l_whence = SEEK_SET;
285 fl.l_start = 0L;
286 fl.l_len = 0L;
287 fl.l_pid = getpid();
288 if (fcntl(fd, F_SETLKW, &fl) < 0) {
289 perror(">>> fcntl file unlock");
290 return 0;
291 }
292 #endif
293 return 1;
294 }
295
296 /* Auto-determine from how the file was opened, what kind of lock to lock
297 * the file with
298 */
299 SB_STATIC int file_locktype(char *mode)
300 {
301 #ifdef USE_FLOCK
302 if (NULL != (strchr(mode, 'w')) || (NULL != strchr(mode, '+'))
303 || (NULL != strchr(mode, 'a')))
304 return (LOCK_EX);
305 return (LOCK_SH);
306 #else
307 if (NULL != (strchr(mode, 'w')) || (NULL != strchr(mode, '+'))
308 || (NULL != strchr(mode, 'a')))
309 return (F_WRLCK);
310 return (F_RDLCK);
311 #endif
312 }
313
314 /* Use standard fopen style modes to open the specified file. Also auto-determines and
315 * locks the file either in shared or exclusive mode depending on opening mode
316 */
317 SB_STATIC int file_open(char *filename, char *mode, int perm_specified, ...)
318 {
319 int fd;
320 char error[SB_BUF_LEN];
321 va_list ap;
322 int perm;
323 char *group = NULL;
324 struct group *group_struct;
325
326 file_security_check(filename);
327
328 if (perm_specified) {
329 va_start(ap, perm_specified);
330 perm = va_arg(ap, int);
331 group = va_arg(ap, char *);
332 va_end(ap);
333 }
334 fd = open(filename, file_getmode(mode));
335 file_security_check(filename);
336 if (-1 == fd) {
337 snprintf(error, sizeof(error), ">>> %s file mode: %s open", filename, mode);
338 perror(error);
339 return (fd);
340 }
341 if (perm_specified) {
342 if (fchmod(fd, 0664) && (0 == getuid())) {
343 snprintf(error, sizeof(error), ">>> Could not set mode: %s", filename);
344 perror(error);
345 }
346 }
347 if (NULL != group) {
348 group_struct = getgrnam(group);
349 if (NULL == group_struct) {
350 snprintf(error, sizeof(error), ">>> Could not get grp number: %s", group);
351 perror(error);
352 } else {
353 if (fchown(fd, -1, group_struct->gr_gid) && (0 == getuid())) {
354 snprintf(error, sizeof(error), ">>> Could not set group: %s", filename);
355 perror(error);
356 }
357 }
358 }
359 /* Only lock the file if opening succeeded */
360 if (-1 != fd) {
361 if (file_security_check(filename) != 0) {
362 /* Security violation occured between the last check and the */
363 /* creation of the file. As SpanKY pointed out there is a race */
364 /* condition here, so if there is a problem here we'll mesg and */
365 /* bail out to avoid it until we can work and test a better fix. */
366 fprintf(stderr, "\n\nSECURITY RACE CONDITION: Problem recurred after creation!\nBAILING OUT\n\n");
367 exit(127);
368 }
369
370 if (0 == file_lock(fd, file_locktype(mode), filename)) {
371 close(fd);
372 return -1;
373 }
374 } else {
375 snprintf(error, sizeof(error), ">>> %s file mode:%s open", filename, mode);
376 perror(error);
377 }
378 return (fd);
379 }
380
381 /* Close and unlock file */
382 SB_STATIC void file_close(int fd)
383 {
384 if (-1 != fd) {
385 file_unlock(fd);
386 close(fd);
387 }
388 }
389
390 /* Return length of file */
391 SB_STATIC long file_length(int fd)
392 {
393 long pos, len;
394 pos = file_tell(fd);
395 len = lseek(fd, 0L, SEEK_END);
396 lseek(fd, pos, SEEK_SET);
397 return (len);
398 }
399
400 /* Zero out file */
401 SB_STATIC int file_truncate(int fd)
402 {
403 lseek(fd, 0L, SEEK_SET);
404 if (ftruncate(fd, 0) < 0) {
405 perror(">>> file truncate");
406 return 0;
407 }
408 return 1;
409 }
410
411 /* Check to see if a file exists Return: 1 success, 0 file not found, -1 error */
412 SB_STATIC int file_exist(char *filename, int checkmode)
413 {
414 struct stat mystat;
415
416 /* Verify file exists and is regular file (not sym link) */
417 if (checkmode) {
418 if (-1 == lstat(filename, &mystat)) {
419 /* file doesn't exist */
420 if (ENOENT == errno) {
421 return 0;
422 } else { /* permission denied or other error */
423 perror(">>> stat file");
424 return -1;
425 }
426 }
427 if (!S_ISREG(mystat.st_mode))
428 return -1;
429
430 /* Just plain verify the file exists */
431 } else {
432 if (-1 == stat(filename, &mystat)) {
433 /* file does not exist */
434 if (ENOENT == errno) {
435 return 0;
436 } else { /* permission denied or other error */
437 perror(">>> stat file");
438 return -1;
439 }
440 }
441 }
442
443 return 1;
444 }
445
446 SB_STATIC int file_security_check(char *filename)
447 { /* 0 == fine, >0 == problem */
448 struct stat stat_buf;
449 struct group *group_buf;
450 struct passwd *passwd_buf;
451
452 passwd_buf = getpwnam("portage");
453 group_buf = getgrnam("portage");
454
455 if ((lstat(filename, &stat_buf) == -1) && (errno == ENOENT)) {
456 /* Doesn't exist. */
457 return 0;
458 } else {
459 if ((stat_buf.st_nlink) > 1) { /* Security: We are handlinked... */
460 if (unlink(filename)) {
461 fprintf(stderr, "Unable to delete file in security violation (hardlinked): %s\n", filename);
462 exit(127);
463 }
464 fprintf(stderr, "File in security violation (hardlinked): %s\n", filename);
465 return 1;
466 } else if (S_ISLNK(stat_buf.st_mode)) { /* Security: We are a symlink? */
467 fprintf(stderr, "File in security violation (symlink): %s\n", filename);
468 exit(127);
469 } else if (0 == S_ISREG(stat_buf.st_mode)) { /* Security: special file */
470 fprintf(stderr, "File in security violation (not regular): %s\n", filename);
471 exit(127);
472 } else if (stat_buf.st_mode & S_IWOTH) { /* Security: We are o+w? */
473 if (unlink(filename)) {
474 fprintf(stderr, "Unable to delete file in security violation (world write): %s\n", filename);
475 exit(127);
476 }
477 fprintf(stderr, "File in security violation (world write): %s\n", filename);
478 return 1;
479 } else
480 if (!((stat_buf.st_uid == 0) || (stat_buf.st_uid == getuid()) ||
481 ((passwd_buf != NULL) && (stat_buf.st_uid == passwd_buf->pw_uid))) ||
482 !((stat_buf.st_gid == 0) || (stat_buf.st_gid == getgid()) ||
483 ((group_buf != NULL) && (stat_buf.st_gid == group_buf->gr_gid)))) {
484 /* Security: Owner/Group isn't right. */
485
486 /* uid = 0 or myuid or portage */
487 /* gid = 0 or mygid or portage */
488
489 if (0) {
490 fprintf(stderr, "--1: %d,%d,%d,%d\n--2: %d,%d,%d,%d\n",
491 (stat_buf.st_uid == 0),
492 (stat_buf.st_uid == getuid()),
493 (passwd_buf != NULL),
494 (passwd_buf != NULL) ? (stat_buf.st_uid == passwd_buf->pw_uid) : -1,
495 (stat_buf.st_gid == 0),
496 (stat_buf.st_gid == getgid()),
497 (group_buf != NULL),
498 (group_buf != NULL) ? (stat_buf.st_gid == group_buf->gr_gid) : -1);
499 }
500
501 /* manpage: "The return value may point to static area" */
502 /* DO NOT ACTUALLY FREE THIS... It'll segfault. */
503 /* if(passwd_buf != NULL) { free(passwd_buf); } */
504 /* if(group_buf != NULL) { free(group_buf); } */
505
506 if (unlink(filename)) {
507 fprintf(stderr, "Unable to delete file in security violation (bad owner/group): %s\n", filename);
508 exit(127);
509 }
510 fprintf(stderr, "File in security violation (bad owner/group): %s\n", filename);
511 return 1;
512 }
513 } /* Stat */
514 return 0;
515 }
516
517 // vim:noexpandtab noai:cindent ai

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