1 /* ====================================================================
2 * The Apache Software License, Version 1.1
4 * Copyright (c) 2000-2001 The Apache Software Foundation. All rights
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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.
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31 * 5. Products derived from this software may not be called "Apache",
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33 * permission of the Apache Software Foundation.
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37 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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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>
94 ***********************************************************************
95 * There is no initgroups() in QNX, so I believe this is safe :-)
96 * Use cc -osuexec -3 -O -mf -DQNX suexec.c to compile.
99 * Igor N. Kovalenko -- infoh@mail.wplus.net
100 ***********************************************************************
103 #if defined(NEED_INITGROUPS)
104 int initgroups(const char *name, gid_t basegid)
106 /* QNX and MPE do not appear to support supplementary groups. */
111 #if defined(PATH_MAX)
112 #define AP_MAXPATH PATH_MAX
113 #elif defined(MAXPATHLEN)
114 #define AP_MAXPATH MAXPATHLEN
116 #define AP_MAXPATH 8192
119 #define AP_ENVBUF 256
121 extern char **environ;
122 static FILE *log = NULL;
124 char *safe_env_lst[] =
132 "DOCUMENT_PATH_INFO",
141 "QUERY_STRING_UNESCAPED",
147 "REDIRECT_QUERY_STRING",
169 static void err_output(const char *fmt, va_list ap)
176 if ((log = fopen(AP_LOG_EXEC, "a")) == NULL) {
177 fprintf(stderr, "failed to open log file\n");
184 lt = localtime(&timevar);
186 fprintf(log, "[%d-%.2d-%.2d %.2d:%.2d:%.2d]: ",
187 lt->tm_year + 1900, lt->tm_mon + 1, lt->tm_mday,
188 lt->tm_hour, lt->tm_min, lt->tm_sec);
190 vfprintf(log, fmt, ap);
193 #endif /* AP_LOG_EXEC */
197 static void log_err(const char *fmt,...)
205 #endif /* AP_LOG_EXEC */
209 static void clean_env(void)
218 if ((cleanenv = (char **) calloc(AP_ENVBUF, sizeof(char *))) == NULL) {
219 log_err("failed to malloc memory for environment\n");
223 sprintf(pathbuf, "PATH=%s", AP_SAFE_PATH);
224 cleanenv[cidx] = strdup(pathbuf);
227 for (ep = environ; *ep && cidx < AP_ENVBUF-1; ep++) {
228 if (!strncmp(*ep, "HTTP_", 5)) {
229 cleanenv[cidx] = *ep;
233 for (idx = 0; safe_env_lst[idx]; idx++) {
234 if (!strncmp(*ep, safe_env_lst[idx],
235 strlen(safe_env_lst[idx]))) {
236 cleanenv[cidx] = *ep;
244 cleanenv[cidx] = NULL;
249 int main(int argc, char *argv[])
251 int userdir = 0; /* ~userdir flag */
252 uid_t uid; /* user information */
253 gid_t gid; /* target group placeholder */
254 char *target_uname; /* target user name */
255 char *target_gname; /* target group name */
256 char *target_homedir; /* target home directory */
257 char *actual_uname; /* actual user name */
258 char *actual_gname; /* actual group name */
259 char *prog; /* name of this program */
260 char *cmd; /* command to be executed */
261 char cwd[AP_MAXPATH]; /* current working directory */
262 char dwd[AP_MAXPATH]; /* docroot working directory */
263 struct passwd *pw; /* password entry holder */
264 struct group *gr; /* group entry holder */
265 struct stat dir_info; /* directory info holder */
266 struct stat prg_info; /* program info holder */
269 * If there are a proper number of arguments, set
270 * all of them to variables. Otherwise, error out.
274 log_err("too few arguments\n");
277 target_uname = argv[1];
278 target_gname = argv[2];
282 * Check existence/validity of the UID of the user
283 * running this program. Error out if invalid.
286 if ((pw = getpwuid(uid)) == NULL) {
287 log_err("invalid uid: (%ld)\n", uid);
292 * Check to see if the user running this program
293 * is the user allowed to do so as defined in
294 * suexec.h. If not the allowed user, error out.
297 /* User name comparisons are case insensitive on BS2000/OSD */
298 if (strcasecmp(AP_HTTPD_USER, pw->pw_name)) {
299 log_err("user mismatch (%s instead of %s)\n", pw->pw_name, AP_HTTPD_USER);
303 if (strcmp(AP_HTTPD_USER, pw->pw_name)) {
304 log_err("user mismatch (%s instead of %s)\n", pw->pw_name, AP_HTTPD_USER);
307 #endif /*_OSD_POSIX*/
310 * Check for a leading '/' (absolute path) in the command to be executed,
311 * or attempts to back up out of the current directory,
312 * to protect against attacks. If any are
313 * found, error out. Naughty naughty crackers.
315 if ((cmd[0] == '/') || (!strncmp(cmd, "../", 3))
316 || (strstr(cmd, "/../") != NULL)) {
317 log_err("invalid command (%s)\n", cmd);
322 * Check to see if this is a ~userdir request. If
323 * so, set the flag, and remove the '~' from the
326 if (!strncmp("~", target_uname, 1)) {
332 * Error out if the target username is invalid.
334 if (strspn(target_uname, "1234567890") != strlen(target_uname)) {
335 if ((pw = getpwnam(target_uname)) == NULL) {
336 log_err("invalid target user name: (%s)\n", target_uname);
341 if ((pw = getpwuid(atoi(target_uname))) == NULL) {
342 log_err("invalud target user id: (%s)\n", target_uname);
348 * Error out if the target group name is invalid.
350 if (strspn(target_gname, "1234567890") != strlen(target_gname)) {
351 if ((gr = getgrnam(target_gname)) == NULL) {
352 log_err("invalid target group name: (%s)\n", target_gname);
356 actual_gname = strdup(gr->gr_name);
359 gid = atoi(target_gname);
360 actual_gname = strdup(target_gname);
365 * Initialize BS2000 user environment
371 switch (pid = ufork(target_uname))
374 log_err("failed to setup bs2000 environment for user %s: %s\n",
375 target_uname, strerror(errno));
379 default: /* Father */
380 while (pid != waitpid(pid, &status, 0))
382 /* @@@ FIXME: should we deal with STOP signals as well? */
383 if (WIFSIGNALED(status))
384 kill (getpid(), WTERMSIG(status));
385 exit(WEXITSTATUS(status));
388 #endif /*_OSD_POSIX*/
391 * Save these for later since initgroups will hose the struct
394 actual_uname = strdup(pw->pw_name);
395 target_homedir = strdup(pw->pw_dir);
398 * Log the transaction here to be sure we have an open log
399 * before we setuid().
401 log_err("uid: (%s/%s) gid: (%s/%s) cmd: %s\n",
402 target_uname, actual_uname,
403 target_gname, actual_gname,
407 * Error out if attempt is made to execute as root or as
408 * a UID less than AP_UID_MIN. Tsk tsk.
410 if ((uid == 0) || (uid < AP_UID_MIN)) {
411 log_err("cannot run as forbidden uid (%d/%s)\n", uid, cmd);
416 * Error out if attempt is made to execute as root group
417 * or as a GID less than AP_GID_MIN. Tsk tsk.
419 if ((gid == 0) || (gid < AP_GID_MIN)) {
420 log_err("cannot run as forbidden gid (%d/%s)\n", gid, cmd);
425 * Change UID/GID here so that the following tests work over NFS.
427 * Initialize the group access list for the target user,
428 * and setgid() to the target group. If unsuccessful, error out.
430 if (((setgid(gid)) != 0) || (initgroups(actual_uname, gid) != 0)) {
431 log_err("failed to setgid (%ld: %s)\n", gid, cmd);
436 * setuid() to the target user. Error out on fail.
438 if ((setuid(uid)) != 0) {
439 log_err("failed to setuid (%ld: %s)\n", uid, cmd);
444 * Get the current working directory, as well as the proper
445 * document root (dependant upon whether or not it is a
446 * ~userdir request). Error out if we cannot get either one,
447 * or if the current working directory is not in the docroot.
448 * Use chdir()s and getcwd()s to avoid problems with symlinked
451 if (getcwd(cwd, AP_MAXPATH) == NULL) {
452 log_err("cannot get current working directory\n");
457 if (((chdir(target_homedir)) != 0) ||
458 ((chdir(AP_USERDIR_SUFFIX)) != 0) ||
459 ((getcwd(dwd, AP_MAXPATH)) == NULL) ||
460 ((chdir(cwd)) != 0)) {
461 log_err("cannot get docroot information (%s)\n", target_homedir);
466 if (((chdir(AP_DOC_ROOT)) != 0) ||
467 ((getcwd(dwd, AP_MAXPATH)) == NULL) ||
468 ((chdir(cwd)) != 0)) {
469 log_err("cannot get docroot information (%s)\n", AP_DOC_ROOT);
474 if ((strncmp(cwd, dwd, strlen(dwd))) != 0) {
475 log_err("command not in docroot (%s/%s)\n", cwd, cmd);
480 * Stat the cwd and verify it is a directory, or error out.
482 if (((lstat(cwd, &dir_info)) != 0) || !(S_ISDIR(dir_info.st_mode))) {
483 log_err("cannot stat directory: (%s)\n", cwd);
488 * Error out if cwd is writable by others.
490 if ((dir_info.st_mode & S_IWOTH) || (dir_info.st_mode & S_IWGRP)) {
491 log_err("directory is writable by others: (%s)\n", cwd);
496 * Error out if we cannot stat the program.
498 if (((lstat(cmd, &prg_info)) != 0) || (S_ISLNK(prg_info.st_mode))) {
499 log_err("cannot stat program: (%s)\n", cmd);
504 * Error out if the program is writable by others.
506 if ((prg_info.st_mode & S_IWOTH) || (prg_info.st_mode & S_IWGRP)) {
507 log_err("file is writable by others: (%s/%s)\n", cwd, cmd);
512 * Error out if the file is setuid or setgid.
514 if ((prg_info.st_mode & S_ISUID) || (prg_info.st_mode & S_ISGID)) {
515 log_err("file is either setuid or setgid: (%s/%s)\n", cwd, cmd);
520 * Error out if the target name/group is different from
521 * the name/group of the cwd or the program.
523 if ((uid != dir_info.st_uid) ||
524 (gid != dir_info.st_gid) ||
525 (uid != prg_info.st_uid) ||
526 (gid != prg_info.st_gid)) {
527 log_err("target uid/gid (%ld/%ld) mismatch "
528 "with directory (%ld/%ld) or program (%ld/%ld)\n",
530 dir_info.st_uid, dir_info.st_gid,
531 prg_info.st_uid, prg_info.st_gid);
535 * Error out if the program is not executable for the user.
536 * Otherwise, she won't find any error in the logs except for
537 * "[error] Premature end of script headers: ..."
539 if (!(prg_info.st_mode & S_IXUSR)) {
540 log_err("file has no execute permission: (%s/%s)\n", cwd, cmd);
547 * Be sure to close the log file so the CGI can't
548 * mess with it. If the exec fails, it will be reopened
549 * automatically when log_err is called. Note that the log
550 * might not actually be open if AP_LOG_EXEC isn't defined.
551 * However, the "log" cell isn't ifdef'd so let's be defensive
552 * and assume someone might have done something with it
553 * outside an ifdef'd AP_LOG_EXEC block.
561 * Execute the command, replacing our image with its own.
563 #ifdef NEED_HASHBANG_EMUL
564 /* We need the #! emulation when we want to execute scripts */
566 extern char **environ;
568 ap_execve(cmd, &argv[3], environ);
570 #else /*NEED_HASHBANG_EMUL*/
571 execv(cmd, &argv[3]);
572 #endif /*NEED_HASHBANG_EMUL*/
575 * (I can't help myself...sorry.)
577 * Uh oh. Still here. Where's the kaboom? There was supposed to be an
578 * EARTH-shattering kaboom!
580 * Oh well, log the failure and error out.
582 log_err("(%d)%s: exec failed (%s)\n", errno,
583 strerror(errno), cmd);