1 /* vi: set sw=4 ts=4: */
5 * Copyright (C) tons of folks. Tracking down who wrote what
6 * isn't something I'm going to worry about... If you wrote something
7 * here, please feel free to acknowledge your work.
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 * Based in part on code from sash, Copyright (c) 1999 by David I. Bell
24 * Permission has been granted to redistribute this code under the GPL.
35 const char usage_messages[] =
51 static struct BB_applet *applet_using;
53 /* The -1 arises because of the {0,NULL,0,-1} entry above. */
54 const size_t NUM_APPLETS = (sizeof (applets) / sizeof (struct BB_applet) - 1);
57 #ifdef CONFIG_FEATURE_SUID
59 static void check_suid (struct BB_applet *app);
61 #ifdef CONFIG_FEATURE_SUID_CONFIG
68 static void parse_config_file (void);
70 #define CONFIG_FILE "/etc/busybox.conf"
72 /* applets [] is const, so we have to define this "override" structure */
75 struct BB_applet *m_applet;
81 struct BB_suid_config *m_next;
84 static struct BB_suid_config *suid_config;
85 static int suid_cfg_readable;
87 #endif /* CONFIG_FEATURE_SUID_CONFIG */
89 #endif /* CONFIG_FEATURE_SUID */
96 const char *format_string;
97 const char *usage_string = usage_messages;
100 for (i = applet_using - applets; i > 0;) {
101 if (!*usage_string++) {
106 format_string = "%s\n\nUsage: %s %s\n\n";
107 if (*usage_string == '\b')
108 format_string = "%s\n\nNo help available.\n\n";
109 fprintf (stderr, format_string, bb_msg_full_version, applet_using->name,
116 applet_name_compare (const void *x, const void *y)
118 const char *name = x;
119 const struct BB_applet *applet = y;
121 return strcmp (name, applet->name);
124 extern const size_t NUM_APPLETS;
127 find_applet_by_name (const char *name)
129 return bsearch (name, applets, NUM_APPLETS, sizeof (struct BB_applet),
130 applet_name_compare);
134 run_applet_by_name (const char *name, int argc, char **argv)
136 static int recurse_level = 0;
137 extern int been_there_done_that; /* From busybox.c */
139 #ifdef CONFIG_FEATURE_SUID_CONFIG
140 if (recurse_level == 0)
141 parse_config_file ();
145 /* Do a binary search to find the applet entry given the name. */
146 if ((applet_using = find_applet_by_name (name)) != NULL) {
147 bb_applet_name = applet_using->name;
148 if (argv[1] && strcmp (argv[1], "--help") == 0) {
149 if (strcmp (applet_using->name, "busybox") == 0) {
151 applet_using = find_applet_by_name (argv[2]);
157 been_there_done_that = 1;
158 busybox_main (0, NULL);
160 #ifdef CONFIG_FEATURE_SUID
161 check_suid (applet_using);
164 exit ((*(applet_using->main)) (argc, argv));
166 /* Just in case they have renamed busybox - Check argv[1] */
167 if (recurse_level == 1) {
168 run_applet_by_name ("busybox", argc, argv);
174 #ifdef CONFIG_FEATURE_SUID
176 #ifdef CONFIG_FEATURE_SUID_CONFIG
178 /* check if u is member of group g */
180 ingroup (uid_t u, gid_t g)
182 struct group *grp = getgrgid (g);
187 for (mem = grp->gr_mem; *mem; mem++) {
188 struct passwd *pwd = getpwnam (*mem);
190 if (pwd && (pwd->pw_uid == u))
201 check_suid (struct BB_applet *applet)
203 uid_t ruid = getuid (); /* real [ug]id */
204 uid_t rgid = getgid ();
206 #ifdef CONFIG_FEATURE_SUID_CONFIG
207 if (suid_cfg_readable) {
208 struct BB_suid_config *sct;
210 for (sct = suid_config; sct; sct = sct->m_next) {
211 if (sct->m_applet == applet)
215 mode_t m = sct->m_mode;
217 if (sct->m_uid == ruid) /* same uid */
219 else if ((sct->m_gid == rgid) || ingroup (ruid, sct->m_gid)) /* same group / in group */
222 if (!(m & S_IXOTH)) /* is x bit not set ? */
223 bb_error_msg_and_die ("You have no permission to run this applet!");
225 if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { /* *both* have to be set for sgid */
226 if (setegid (sct->m_gid))
228 ("BusyBox binary has insufficient rights to set proper GID for applet!");
230 setgid (rgid); /* no sgid -> drop */
232 if (sct->m_mode & S_ISUID) {
233 if (seteuid (sct->m_uid))
235 ("BusyBox binary has insufficient rights to set proper UID for applet!");
237 setuid (ruid); /* no suid -> drop */
239 /* default: drop all priviledges */
245 #ifndef CONFIG_FEATURE_SUID_CONFIG_QUIET
246 static int onetime = 0;
250 fprintf (stderr, "Using fallback suid method\n");
256 if (applet->need_suid == _BB_SUID_ALWAYS) {
258 bb_error_msg_and_die ("This applet requires root priviledges!");
259 } else if (applet->need_suid == _BB_SUID_NEVER) {
260 setgid (rgid); /* drop all priviledges */
265 #ifdef CONFIG_FEATURE_SUID_CONFIG
267 /* This should probably be a libbb routine. In that case,
268 * I'd probably rename it to something like bb_trimmed_slice.
270 static char *get_trimmed_slice(char *s, char *e)
272 /* First, consider the value at e to be nul and back up until we
273 * reach a non-space char. Set the char after that (possibly at
274 * the original e) to nul. */
282 /* Next, advance past all leading space and return a ptr to the
283 * first non-space char; possibly the terminating nul. */
284 return (char *) bb_skip_whitespace(s);
288 #define parse_error(x) { err=x; goto pe_label; }
290 /* Don't depend on the tools to combine strings. */
291 static const char config_file[] = CONFIG_FILE;
293 /* There are 4 chars + 1 nul for each of user/group/other. */
294 static const char mode_chars[] = "Ssx-\0Ssx-\0Ttx-";
296 /* We don't supply a value for the nul, so an index adjustment is
297 * necessary below. Also, we use unsigned short here to save some
298 * space even though these are really mode_t values. */
299 static const unsigned short mode_mask[] = {
300 /* SST sst xxx --- */
301 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
302 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
303 0, S_IXOTH, S_IXOTH, 0 /* other */
306 static void parse_config_file(void)
308 struct BB_suid_config *sct_head;
309 struct BB_suid_config *sct;
310 struct BB_applet *applet;
319 assert(!suid_config); /* Should be set to NULL by bss init. */
321 if ((stat(config_file, &st) != 0) /* No config file? */
322 || !S_ISREG(st.st_mode) /* Not a regular file? */
323 || (st.st_uid != 0) /* Not owned by root? */
324 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
325 || !(f = fopen(config_file, "r")) /* Can not open? */
330 suid_cfg_readable = 1;
337 if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
338 if (ferror(f)) { /* Make sure it wasn't a read error. */
339 parse_error("reading");
342 suid_config = sct_head; /* Success, so set the pointer. */
346 lc++; /* Got a (partial) line. */
348 /* If a line is too long for our buffer, we consider it an error.
349 * The following test does mistreat one corner case though.
350 * If the final line of the file does not end with a newline and
351 * yet exactly fills the buffer, it will be treated as too long
352 * even though there isn't really a problem. But it isn't really
353 * worth adding code to deal with such an unlikely situation, and
354 * we do err on the side of caution. Besides, the line would be
355 * too long if it did end with a newline. */
356 if (!strchr(s, '\n') && !feof(f)) {
357 parse_error("line too long");
360 /* Trim leading and trailing whitespace, ignoring comments, and
361 * check if the resulting string is empty. */
362 if (!*(s = get_trimmed_slice(s, strchrnul(s, '#')))) {
366 /* Check for a section header. */
369 /* Unlike the old code, we ignore leading and trailing
370 * whitespace for the section name. We also require that
371 * there are no stray characters after the closing bracket. */
372 if (!(e = strchr(s, ']')) /* Missing right bracket? */
373 || e[1] /* Trailing characters? */
374 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
376 parse_error("section header");
378 /* Right now we only have one section so just check it.
379 * If more sections are added in the future, please don't
380 * resort to cascading ifs with multiple strcasecmp calls.
381 * That kind of bloated code is all too common. A loop
382 * and a string table would be a better choice unless the
383 * number of sections is very small. */
384 if (strcasecmp(s, "SUID") == 0) {
388 section = -1; /* Unknown section so set to skip. */
392 /* Process sections. */
394 if (section == 1) { /* SUID */
395 /* Since we trimmed leading and trailing space above, we're
396 * now looking for strings of the form
397 * <key>[::space::]*=[::space::]*<value>
398 * where both key and value could contain inner whitespace. */
400 /* First get the key (an applet name in our case). */
401 if (!!(e = strchr(s, '='))) {
402 s = get_trimmed_slice(s, e);
404 if (!e || !*s) { /* Missing '=' or empty key. */
405 parse_error("keyword");
408 /* Ok, we have an applet name. Process the rhs if this
409 * applet is currently built in and ignore it otherwise.
410 * Note: This can hide config file bugs which only pop
411 * up when the busybox configuration is changed. */
412 if ((applet = find_applet_by_name(s))) {
413 /* Note: We currently don't check for duplicates!
414 * The last config line for each applet will be the
415 * one used since we insert at the head of the list.
416 * I suppose this could be considered a feature. */
417 sct = xmalloc(sizeof(struct BB_suid_config));
418 sct->m_applet = applet;
420 sct->m_next = sct_head;
423 /* Get the specified mode. */
425 e = (char *) bb_skip_whitespace(e+1);
427 for (i=0 ; i < 3 ; i++) {
429 if (!*(q = strchrnul(mode_chars + 5*i, *e++))) {
432 /* Adjust by -i to account for nul. */
433 sct->m_mode |= mode_mask[(q - mode_chars) - i];
436 /* Now get the the user/group info. */
438 s = (char *) bb_skip_whitespace(e);
440 /* Note: We require whitespace between the mode and the
441 * user/group info. */
442 if ((s == e) || !(e = strchr(s, '.'))) {
443 parse_error("<uid>.<gid>");
447 /* We can't use get_ug_id here since it would exit()
448 * if a uid or gid was not found. Oh well... */
452 sct->m_uid = strtoul(s, &e2, 10);
453 if (*e2 || (s == e2)) {
455 if (!(pwd = getpwnam(s))) {
458 sct->m_uid = pwd->pw_uid;
461 sct->m_gid = strtoul(e, &e2, 10);
462 if (*e2 || (e == e2)) {
464 if (!(grp = getgrnam(e))) {
465 parse_error("group");
467 sct->m_gid = grp->gr_gid;
474 /* Unknown sections are ignored. */
476 /* Encountering configuration lines prior to seeing a
477 * section header is treated as an error. This is how
478 * the old code worked, but it may not be desirable.
479 * We may want to simply ignore such lines in case they
480 * are used in some future version of busybox. */
482 parse_error("keyword outside section");
488 fprintf(stderr, "Parse error in %s, line %d: %s\n",
489 config_file, lc, err);
492 /* Release any allocated memory before returning. */
494 sct = sct_head->m_next;
508 c-file-style: "linux"