1 /* ====================================================================
2 * The Apache Software License, Version 1.1
4 * Copyright (c) 2000 The Apache Software Foundation. All rights
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in
16 * the documentation and/or other materials provided with the
19 * 3. The end-user documentation included with the redistribution,
20 * if any, must include the following acknowledgment:
21 * "This product includes software developed by the
22 * Apache Software Foundation (http://www.apache.org/)."
23 * Alternately, this acknowledgment may appear in the software itself,
24 * if and wherever such third-party acknowledgments normally appear.
26 * 4. The names "Apache" and "Apache Software Foundation" must
27 * not be used to endorse or promote products derived from this
28 * software without prior written permission. For written
29 * permission, please contact apache@apache.org.
31 * 5. Products derived from this software may not be called "Apache",
32 * nor may "Apache" appear in their name, without prior written
33 * permission of the Apache Software Foundation.
35 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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37 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
38 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
39 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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41 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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43 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
44 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
45 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
47 * ====================================================================
49 * This software consists of voluntary contributions made by many
50 * individuals on behalf of the Apache Software Foundation. For more
51 * information on the Apache Software Foundation, please see
52 * <http://www.apache.org/>.
56 * suexec.c -- "Wrapper" support program for suEXEC behaviour for Apache
58 ***********************************************************************
60 * NOTE! : DO NOT edit this code!!! Unless you know what you are doing,
61 * editing this code might open up your system in unexpected
62 * ways to would-be crackers. Every precaution has been taken
63 * to make this code as safe as possible; alter it at your own
66 ***********************************************************************
71 #include "ap_config.h"
72 #include <sys/param.h>
74 #include <sys/types.h>
81 ***********************************************************************
82 * There is no initgroups() in QNX, so I believe this is safe :-)
83 * Use cc -osuexec -3 -O -mf -DQNX suexec.c to compile.
86 * Igor N. Kovalenko -- infoh@mail.wplus.net
87 ***********************************************************************
90 #if defined(NEED_INITGROUPS)
91 int initgroups(const char *name, gid_t basegid)
93 /* QNX and MPE do not appear to support supplementary groups. */
99 #define AP_MAXPATH PATH_MAX
100 #elif defined(MAXPATHLEN)
101 #define AP_MAXPATH MAXPATHLEN
103 #define AP_MAXPATH 8192
106 #define AP_ENVBUF 256
108 extern char **environ;
109 static FILE *log = NULL;
111 char *safe_env_lst[] =
119 "DOCUMENT_PATH_INFO",
128 "QUERY_STRING_UNESCAPED",
134 "REDIRECT_QUERY_STRING",
156 static void err_output(const char *fmt, va_list ap)
163 if ((log = fopen(LOG_EXEC, "a")) == NULL) {
164 fprintf(stderr, "failed to open log file\n");
171 lt = localtime(&timevar);
173 fprintf(log, "[%d-%.2d-%.2d %.2d:%.2d:%.2d]: ",
174 lt->tm_year + 1900, lt->tm_mon + 1, lt->tm_mday,
175 lt->tm_hour, lt->tm_min, lt->tm_sec);
177 vfprintf(log, fmt, ap);
180 #endif /* LOG_EXEC */
184 static void log_err(const char *fmt,...)
192 #endif /* LOG_EXEC */
196 static void clean_env(void)
205 if ((cleanenv = (char **) calloc(AP_ENVBUF, sizeof(char *))) == NULL) {
206 log_err("failed to malloc memory for environment\n");
210 sprintf(pathbuf, "PATH=%s", SAFE_PATH);
211 cleanenv[cidx] = strdup(pathbuf);
214 for (ep = environ; *ep && cidx < AP_ENVBUF-1; ep++) {
215 if (!strncmp(*ep, "HTTP_", 5)) {
216 cleanenv[cidx] = *ep;
220 for (idx = 0; safe_env_lst[idx]; idx++) {
221 if (!strncmp(*ep, safe_env_lst[idx],
222 strlen(safe_env_lst[idx]))) {
223 cleanenv[cidx] = *ep;
231 cleanenv[cidx] = NULL;
236 int main(int argc, char *argv[])
238 int userdir = 0; /* ~userdir flag */
239 uid_t uid; /* user information */
240 gid_t gid; /* target group placeholder */
241 char *target_uname; /* target user name */
242 char *target_gname; /* target group name */
243 char *target_homedir; /* target home directory */
244 char *actual_uname; /* actual user name */
245 char *actual_gname; /* actual group name */
246 char *prog; /* name of this program */
247 char *cmd; /* command to be executed */
248 char cwd[AP_MAXPATH]; /* current working directory */
249 char dwd[AP_MAXPATH]; /* docroot working directory */
250 struct passwd *pw; /* password entry holder */
251 struct group *gr; /* group entry holder */
252 struct stat dir_info; /* directory info holder */
253 struct stat prg_info; /* program info holder */
256 * If there are a proper number of arguments, set
257 * all of them to variables. Otherwise, error out.
261 log_err("too few arguments\n");
264 target_uname = argv[1];
265 target_gname = argv[2];
269 * Check existence/validity of the UID of the user
270 * running this program. Error out if invalid.
273 if ((pw = getpwuid(uid)) == NULL) {
274 log_err("invalid uid: (%ld)\n", uid);
279 * Check to see if the user running this program
280 * is the user allowed to do so as defined in
281 * suexec.h. If not the allowed user, error out.
284 /* User name comparisons are case insensitive on BS2000/OSD */
285 if (strcasecmp(HTTPD_USER, pw->pw_name)) {
286 log_err("user mismatch (%s instead of %s)\n", pw->pw_name, HTTPD_USER);
290 if (strcmp(HTTPD_USER, pw->pw_name)) {
291 log_err("user mismatch (%s instead of %s)\n", pw->pw_name, HTTPD_USER);
294 #endif /*_OSD_POSIX*/
297 * Check for a leading '/' (absolute path) in the command to be executed,
298 * or attempts to back up out of the current directory,
299 * to protect against attacks. If any are
300 * found, error out. Naughty naughty crackers.
302 if ((cmd[0] == '/') || (!strncmp(cmd, "../", 3))
303 || (strstr(cmd, "/../") != NULL)) {
304 log_err("invalid command (%s)\n", cmd);
309 * Check to see if this is a ~userdir request. If
310 * so, set the flag, and remove the '~' from the
313 if (!strncmp("~", target_uname, 1)) {
319 * Error out if the target username is invalid.
321 if ((pw = getpwnam(target_uname)) == NULL) {
322 log_err("invalid target user name: (%s)\n", target_uname);
327 * Error out if the target group name is invalid.
329 if (strspn(target_gname, "1234567890") != strlen(target_gname)) {
330 if ((gr = getgrnam(target_gname)) == NULL) {
331 log_err("invalid target group name: (%s)\n", target_gname);
335 actual_gname = strdup(gr->gr_name);
338 gid = atoi(target_gname);
339 actual_gname = strdup(target_gname);
344 * Initialize BS2000 user environment
350 switch (pid = ufork(target_uname))
353 log_err("failed to setup bs2000 environment for user %s: %s\n",
354 target_uname, strerror(errno));
358 default: /* Father */
359 while (pid != waitpid(pid, &status, 0))
361 /* @@@ FIXME: should we deal with STOP signals as well? */
362 if (WIFSIGNALED(status))
363 kill (getpid(), WTERMSIG(status));
364 exit(WEXITSTATUS(status));
367 #endif /*_OSD_POSIX*/
370 * Save these for later since initgroups will hose the struct
373 actual_uname = strdup(pw->pw_name);
374 target_homedir = strdup(pw->pw_dir);
377 * Log the transaction here to be sure we have an open log
378 * before we setuid().
380 log_err("uid: (%s/%s) gid: (%s/%s) cmd: %s\n",
381 target_uname, actual_uname,
382 target_gname, actual_gname,
386 * Error out if attempt is made to execute as root or as
387 * a UID less than UID_MIN. Tsk tsk.
389 if ((uid == 0) || (uid < UID_MIN)) {
390 log_err("cannot run as forbidden uid (%d/%s)\n", uid, cmd);
395 * Error out if attempt is made to execute as root group
396 * or as a GID less than GID_MIN. Tsk tsk.
398 if ((gid == 0) || (gid < GID_MIN)) {
399 log_err("cannot run as forbidden gid (%d/%s)\n", gid, cmd);
404 * Change UID/GID here so that the following tests work over NFS.
406 * Initialize the group access list for the target user,
407 * and setgid() to the target group. If unsuccessful, error out.
409 if (((setgid(gid)) != 0) || (initgroups(actual_uname, gid) != 0)) {
410 log_err("failed to setgid (%ld: %s)\n", gid, cmd);
415 * setuid() to the target user. Error out on fail.
417 if ((setuid(uid)) != 0) {
418 log_err("failed to setuid (%ld: %s)\n", uid, cmd);
423 * Get the current working directory, as well as the proper
424 * document root (dependant upon whether or not it is a
425 * ~userdir request). Error out if we cannot get either one,
426 * or if the current working directory is not in the docroot.
427 * Use chdir()s and getcwd()s to avoid problems with symlinked
430 if (getcwd(cwd, AP_MAXPATH) == NULL) {
431 log_err("cannot get current working directory\n");
436 if (((chdir(target_homedir)) != 0) ||
437 ((chdir(USERDIR_SUFFIX)) != 0) ||
438 ((getcwd(dwd, AP_MAXPATH)) == NULL) ||
439 ((chdir(cwd)) != 0)) {
440 log_err("cannot get docroot information (%s)\n", target_homedir);
445 if (((chdir(DOC_ROOT)) != 0) ||
446 ((getcwd(dwd, AP_MAXPATH)) == NULL) ||
447 ((chdir(cwd)) != 0)) {
448 log_err("cannot get docroot information (%s)\n", DOC_ROOT);
453 if ((strncmp(cwd, dwd, strlen(dwd))) != 0) {
454 log_err("command not in docroot (%s/%s)\n", cwd, cmd);
459 * Stat the cwd and verify it is a directory, or error out.
461 if (((lstat(cwd, &dir_info)) != 0) || !(S_ISDIR(dir_info.st_mode))) {
462 log_err("cannot stat directory: (%s)\n", cwd);
467 * Error out if cwd is writable by others.
469 if ((dir_info.st_mode & S_IWOTH) || (dir_info.st_mode & S_IWGRP)) {
470 log_err("directory is writable by others: (%s)\n", cwd);
475 * Error out if we cannot stat the program.
477 if (((lstat(cmd, &prg_info)) != 0) || (S_ISLNK(prg_info.st_mode))) {
478 log_err("cannot stat program: (%s)\n", cmd);
483 * Error out if the program is writable by others.
485 if ((prg_info.st_mode & S_IWOTH) || (prg_info.st_mode & S_IWGRP)) {
486 log_err("file is writable by others: (%s/%s)\n", cwd, cmd);
491 * Error out if the file is setuid or setgid.
493 if ((prg_info.st_mode & S_ISUID) || (prg_info.st_mode & S_ISGID)) {
494 log_err("file is either setuid or setgid: (%s/%s)\n", cwd, cmd);
499 * Error out if the target name/group is different from
500 * the name/group of the cwd or the program.
502 if ((uid != dir_info.st_uid) ||
503 (gid != dir_info.st_gid) ||
504 (uid != prg_info.st_uid) ||
505 (gid != prg_info.st_gid)) {
506 log_err("target uid/gid (%ld/%ld) mismatch "
507 "with directory (%ld/%ld) or program (%ld/%ld)\n",
509 dir_info.st_uid, dir_info.st_gid,
510 prg_info.st_uid, prg_info.st_gid);
514 * Error out if the program is not executable for the user.
515 * Otherwise, she won't find any error in the logs except for
516 * "[error] Premature end of script headers: ..."
518 if (!(prg_info.st_mode & S_IXUSR)) {
519 log_err("file has no execute permission: (%s/%s)\n", cwd, cmd);
526 * Be sure to close the log file so the CGI can't
527 * mess with it. If the exec fails, it will be reopened
528 * automatically when log_err is called. Note that the log
529 * might not actually be open if LOG_EXEC isn't defined.
530 * However, the "log" cell isn't ifdef'd so let's be defensive
531 * and assume someone might have done something with it
532 * outside an ifdef'd LOG_EXEC block.
540 * Execute the command, replacing our image with its own.
542 #ifdef NEED_HASHBANG_EMUL
543 /* We need the #! emulation when we want to execute scripts */
545 extern char **environ;
547 ap_execve(cmd, &argv[3], environ);
549 #else /*NEED_HASHBANG_EMUL*/
550 execv(cmd, &argv[3]);
551 #endif /*NEED_HASHBANG_EMUL*/
554 * (I can't help myself...sorry.)
556 * Uh oh. Still here. Where's the kaboom? There was supposed to be an
557 * EARTH-shattering kaboom!
559 * Oh well, log the failure and error out.
561 log_err("(%d)%s: exec failed (%s)\n", errno, strerror(errno), cmd);