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

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Revision 93 - (show annotations) (download) (as text)
Thu May 12 00:07:21 2005 UTC (9 years, 7 months ago) by azarah
File MIME type: text/x-csrc
File size: 11876 byte(s)
More path limit fixes.  Declare SB_BUF_LEN global and use it where needed.

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

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