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5b313cc655ddaad5250b5d44e47251d6c9a0e44f
apache-http-server/support/suexec.c
Joshua Slive 5b313cc655 suexec: Allow HTTPS and SSL_* environment variables to be passed 
through to CGI scripts.

PR: 9163
Submitted by:	Brian Reid <breid@customlogic.com>, Zvi Har'El <rl@math.technion.ac.il>
Reviewed by:	Joshua Slive, Lars Eilebrecht, Martin Kraemer


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@93223 13f79535-47bb-0310-9956-ffa450edef68
2002-02-04 15:18:45 +00:00

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/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2000-2001 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
/*
* suexec.c -- "Wrapper" support program for suEXEC behaviour for Apache
*
***********************************************************************
*
* NOTE! : DO NOT edit this code!!! Unless you know what you are doing,
* editing this code might open up your system in unexpected
* ways to would-be crackers. Every precaution has been taken
* to make this code as safe as possible; alter it at your own
* risk.
*
***********************************************************************
*
*
*/
#include "ap_config.h"
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <string.h>
#include <time.h>
#if APR_HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include "suexec.h"
#ifdef HAVE_PWD_H
#include <pwd.h>
#endif
#ifdef HAVE_GRP_H
#include <grp.h>
#endif
/*
***********************************************************************
* There is no initgroups() in QNX, so I believe this is safe :-)
* Use cc -osuexec -3 -O -mf -DQNX suexec.c to compile.
*
* May 17, 1997.
* Igor N. Kovalenko -- infoh@mail.wplus.net
***********************************************************************
*/
#if defined(NEED_INITGROUPS)
int initgroups(const char *name, gid_t basegid)
{
/* QNX and MPE do not appear to support supplementary groups. */
return 0;
}
#endif
#if defined(PATH_MAX)
#define AP_MAXPATH PATH_MAX
#elif defined(MAXPATHLEN)
#define AP_MAXPATH MAXPATHLEN
#else
#define AP_MAXPATH 8192
#endif
#define AP_ENVBUF 256
extern char **environ;
static FILE *log = NULL;
char *safe_env_lst[] =
{
"AUTH_TYPE",
"CONTENT_LENGTH",
"CONTENT_TYPE",
"DATE_GMT",
"DATE_LOCAL",
"DOCUMENT_NAME",
"DOCUMENT_PATH_INFO",
"DOCUMENT_ROOT",
"DOCUMENT_URI",
"FILEPATH_INFO",
"GATEWAY_INTERFACE",
"HTTPS",
"LAST_MODIFIED",
"PATH_INFO",
"PATH_TRANSLATED",
"QUERY_STRING",
"QUERY_STRING_UNESCAPED",
"REMOTE_ADDR",
"REMOTE_HOST",
"REMOTE_IDENT",
"REMOTE_PORT",
"REMOTE_USER",
"REDIRECT_QUERY_STRING",
"REDIRECT_STATUS",
"REDIRECT_URL",
"REQUEST_METHOD",
"REQUEST_URI",
"SCRIPT_FILENAME",
"SCRIPT_NAME",
"SCRIPT_URI",
"SCRIPT_URL",
"SERVER_ADMIN",
"SERVER_NAME",
"SERVER_ADDR",
"SERVER_PORT",
"SERVER_PROTOCOL",
"SERVER_SOFTWARE",
"UNIQUE_ID",
"USER_NAME",
"TZ",
NULL
};
static void err_output(const char *fmt, va_list ap)
{
#ifdef AP_LOG_EXEC
time_t timevar;
struct tm *lt;
if (!log) {
if ((log = fopen(AP_LOG_EXEC, "a")) == NULL) {
fprintf(stderr, "failed to open log file\n");
perror("fopen");
exit(1);
}
}
time(&timevar);
lt = localtime(&timevar);
fprintf(log, "[%d-%.2d-%.2d %.2d:%.2d:%.2d]: ",
lt->tm_year + 1900, lt->tm_mon + 1, lt->tm_mday,
lt->tm_hour, lt->tm_min, lt->tm_sec);
vfprintf(log, fmt, ap);
fflush(log);
#endif /* AP_LOG_EXEC */
return;
}
static void log_err(const char *fmt,...)
{
#ifdef AP_LOG_EXEC
va_list ap;
va_start(ap, fmt);
err_output(fmt, ap);
va_end(ap);
#endif /* AP_LOG_EXEC */
return;
}
static void clean_env(void)
{
char pathbuf[512];
char **cleanenv;
char **ep;
int cidx = 0;
int idx;
if ((cleanenv = (char **) calloc(AP_ENVBUF, sizeof(char *))) == NULL) {
log_err("failed to malloc memory for environment\n");
exit(120);
}
sprintf(pathbuf, "PATH=%s", AP_SAFE_PATH);
cleanenv[cidx] = strdup(pathbuf);
cidx++;
for (ep = environ; *ep && cidx < AP_ENVBUF-1; ep++) {
if (!strncmp(*ep, "HTTP_", 5) || !strncmp(*ep, "SSL_", 4)) {
cleanenv[cidx] = *ep;
cidx++;
}
else {
for (idx = 0; safe_env_lst[idx]; idx++) {
if (!strncmp(*ep, safe_env_lst[idx],
strlen(safe_env_lst[idx]))) {
cleanenv[cidx] = *ep;
cidx++;
break;
}
}
}
}
cleanenv[cidx] = NULL;
environ = cleanenv;
}
int main(int argc, char *argv[])
{
int userdir = 0; /* ~userdir flag */
uid_t uid; /* user information */
gid_t gid; /* target group placeholder */
char *target_uname; /* target user name */
char *target_gname; /* target group name */
char *target_homedir; /* target home directory */
char *actual_uname; /* actual user name */
char *actual_gname; /* actual group name */
char *prog; /* name of this program */
char *cmd; /* command to be executed */
char cwd[AP_MAXPATH]; /* current working directory */
char dwd[AP_MAXPATH]; /* docroot working directory */
struct passwd *pw; /* password entry holder */
struct group *gr; /* group entry holder */
struct stat dir_info; /* directory info holder */
struct stat prg_info; /* program info holder */
prog = argv[0];
/*
* Check existence/validity of the UID of the user
* running this program. Error out if invalid.
*/
uid = getuid();
if ((pw = getpwuid(uid)) == NULL) {
log_err("crit: invalid uid: (%ld)\n", uid);
exit(102);
}
/*
* See if this is a 'how were you compiled' request, and
* comply if so.
*/
if ((argc > 1)
&& (! strcmp(argv[1], "-V"))
&& ((uid == 0)
#ifdef _OSD_POSIX
/* User name comparisons are case insensitive on BS2000/OSD */
|| (! strcasecmp(AP_HTTPD_USER, pw->pw_name)))
#else /* _OSD_POSIX */
|| (! strcmp(AP_HTTPD_USER, pw->pw_name)))
#endif /* _OSD_POSIX */
) {
#ifdef AP_DOC_ROOT
fprintf(stderr, " -D AP_DOC_ROOT=\"%s\"\n", AP_DOC_ROOT);
#endif
#ifdef AP_GID_MIN
fprintf(stderr, " -D AP_GID_MIN=%d\n", AP_GID_MIN);
#endif
#ifdef AP_HTTPD_USER
fprintf(stderr, " -D AP_HTTPD_USER=\"%s\"\n", AP_HTTPD_USER);
#endif
#ifdef AP_LOG_EXEC
fprintf(stderr, " -D AP_LOG_EXEC=\"%s\"\n", AP_LOG_EXEC);
#endif
#ifdef AP_SAFE_PATH
fprintf(stderr, " -D AP_SAFE_PATH=\"%s\"\n", AP_SAFE_PATH);
#endif
#ifdef AP_SUEXEC_UMASK
fprintf(stderr, " -D AP_SUEXEC_UMASK=%03o\n", AP_SUEXEC_UMASK);
#endif
#ifdef AP_UID_MIN
fprintf(stderr, " -D AP_UID_MIN=%d\n", AP_UID_MIN);
#endif
#ifdef AP_USERDIR_SUFFIX
fprintf(stderr, " -D AP_USERDIR_SUFFIX=\"%s\"\n", AP_USERDIR_SUFFIX);
#endif
exit(0);
}
/*
* If there are a proper number of arguments, set
* all of them to variables. Otherwise, error out.
*/
if (argc < 4) {
log_err("too few arguments\n");
exit(101);
}
target_uname = argv[1];
target_gname = argv[2];
cmd = argv[3];
/*
* Check to see if the user running this program
* is the user allowed to do so as defined in
* suexec.h. If not the allowed user, error out.
*/
#ifdef _OSD_POSIX
/* User name comparisons are case insensitive on BS2000/OSD */
if (strcasecmp(AP_HTTPD_USER, pw->pw_name)) {
log_err("user mismatch (%s instead of %s)\n", pw->pw_name, AP_HTTPD_USER);
exit(103);
}
#else /*_OSD_POSIX*/
if (strcmp(AP_HTTPD_USER, pw->pw_name)) {
log_err("user mismatch (%s instead of %s)\n", pw->pw_name, AP_HTTPD_USER);
exit(103);
}
#endif /*_OSD_POSIX*/
/*
* Check for a leading '/' (absolute path) in the command to be executed,
* or attempts to back up out of the current directory,
* to protect against attacks. If any are
* found, error out. Naughty naughty crackers.
*/
if ((cmd[0] == '/') || (!strncmp(cmd, "../", 3))
|| (strstr(cmd, "/../") != NULL)) {
log_err("invalid command (%s)\n", cmd);
exit(104);
}
/*
* Check to see if this is a ~userdir request. If
* so, set the flag, and remove the '~' from the
* target username.
*/
if (!strncmp("~", target_uname, 1)) {
target_uname++;
userdir = 1;
}
/*
* Error out if the target username is invalid.
*/
if (strspn(target_uname, "1234567890") != strlen(target_uname)) {
if ((pw = getpwnam(target_uname)) == NULL) {
log_err("invalid target user name: (%s)\n", target_uname);
exit(105);
}
}
else {
if ((pw = getpwuid(atoi(target_uname))) == NULL) {
log_err("invalud target user id: (%s)\n", target_uname);
exit(121);
}
}
/*
* Error out if the target group name is invalid.
*/
if (strspn(target_gname, "1234567890") != strlen(target_gname)) {
if ((gr = getgrnam(target_gname)) == NULL) {
log_err("invalid target group name: (%s)\n", target_gname);
exit(106);
}
gid = gr->gr_gid;
actual_gname = strdup(gr->gr_name);
}
else {
gid = atoi(target_gname);
actual_gname = strdup(target_gname);
}
#ifdef _OSD_POSIX
/*
* Initialize BS2000 user environment
*/
{
pid_t pid;
int status;
switch (pid = ufork(target_uname)) {
case -1: /* Error */
log_err("failed to setup bs2000 environment for user %s: %s\n",
target_uname, strerror(errno));
exit(150);
case 0: /* Child */
break;
default: /* Father */
while (pid != waitpid(pid, &status, 0))
;
/* @@@ FIXME: should we deal with STOP signals as well? */
if (WIFSIGNALED(status)) {
kill (getpid(), WTERMSIG(status));
}
exit(WEXITSTATUS(status));
}
}
#endif /*_OSD_POSIX*/
/*
* Save these for later since initgroups will hose the struct
*/
uid = pw->pw_uid;
actual_uname = strdup(pw->pw_name);
target_homedir = strdup(pw->pw_dir);
/*
* Log the transaction here to be sure we have an open log
* before we setuid().
*/
log_err("uid: (%s/%s) gid: (%s/%s) cmd: %s\n",
target_uname, actual_uname,
target_gname, actual_gname,
cmd);
/*
* Error out if attempt is made to execute as root or as
* a UID less than AP_UID_MIN. Tsk tsk.
*/
if ((uid == 0) || (uid < AP_UID_MIN)) {
log_err("cannot run as forbidden uid (%d/%s)\n", uid, cmd);
exit(107);
}
/*
* Error out if attempt is made to execute as root group
* or as a GID less than AP_GID_MIN. Tsk tsk.
*/
if ((gid == 0) || (gid < AP_GID_MIN)) {
log_err("cannot run as forbidden gid (%d/%s)\n", gid, cmd);
exit(108);
}
/*
* Change UID/GID here so that the following tests work over NFS.
*
* Initialize the group access list for the target user,
* and setgid() to the target group. If unsuccessful, error out.
*/
if (((setgid(gid)) != 0) || (initgroups(actual_uname, gid) != 0)) {
log_err("failed to setgid (%ld: %s)\n", gid, cmd);
exit(109);
}
/*
* setuid() to the target user. Error out on fail.
*/
if ((setuid(uid)) != 0) {
log_err("failed to setuid (%ld: %s)\n", uid, cmd);
exit(110);
}
/*
* Get the current working directory, as well as the proper
* document root (dependant upon whether or not it is a
* ~userdir request). Error out if we cannot get either one,
* or if the current working directory is not in the docroot.
* Use chdir()s and getcwd()s to avoid problems with symlinked
* directories. Yuck.
*/
if (getcwd(cwd, AP_MAXPATH) == NULL) {
log_err("cannot get current working directory\n");
exit(111);
}
if (userdir) {
if (((chdir(target_homedir)) != 0) ||
((chdir(AP_USERDIR_SUFFIX)) != 0) ||
((getcwd(dwd, AP_MAXPATH)) == NULL) ||
((chdir(cwd)) != 0)) {
log_err("cannot get docroot information (%s)\n", target_homedir);
exit(112);
}
}
else {
if (((chdir(AP_DOC_ROOT)) != 0) ||
((getcwd(dwd, AP_MAXPATH)) == NULL) ||
((chdir(cwd)) != 0)) {
log_err("cannot get docroot information (%s)\n", AP_DOC_ROOT);
exit(113);
}
}
if ((strncmp(cwd, dwd, strlen(dwd))) != 0) {
log_err("command not in docroot (%s/%s)\n", cwd, cmd);
exit(114);
}
/*
* Stat the cwd and verify it is a directory, or error out.
*/
if (((lstat(cwd, &dir_info)) != 0) || !(S_ISDIR(dir_info.st_mode))) {
log_err("cannot stat directory: (%s)\n", cwd);
exit(115);
}
/*
* Error out if cwd is writable by others.
*/
if ((dir_info.st_mode & S_IWOTH) || (dir_info.st_mode & S_IWGRP)) {
log_err("directory is writable by others: (%s)\n", cwd);
exit(116);
}
/*
* Error out if we cannot stat the program.
*/
if (((lstat(cmd, &prg_info)) != 0) || (S_ISLNK(prg_info.st_mode))) {
log_err("cannot stat program: (%s)\n", cmd);
exit(117);
}
/*
* Error out if the program is writable by others.
*/
if ((prg_info.st_mode & S_IWOTH) || (prg_info.st_mode & S_IWGRP)) {
log_err("file is writable by others: (%s/%s)\n", cwd, cmd);
exit(118);
}
/*
* Error out if the file is setuid or setgid.
*/
if ((prg_info.st_mode & S_ISUID) || (prg_info.st_mode & S_ISGID)) {
log_err("file is either setuid or setgid: (%s/%s)\n", cwd, cmd);
exit(119);
}
/*
* Error out if the target name/group is different from
* the name/group of the cwd or the program.
*/
if ((uid != dir_info.st_uid) ||
(gid != dir_info.st_gid) ||
(uid != prg_info.st_uid) ||
(gid != prg_info.st_gid)) {
log_err("target uid/gid (%ld/%ld) mismatch "
"with directory (%ld/%ld) or program (%ld/%ld)\n",
uid, gid,
dir_info.st_uid, dir_info.st_gid,
prg_info.st_uid, prg_info.st_gid);
exit(120);
}
/*
* Error out if the program is not executable for the user.
* Otherwise, she won't find any error in the logs except for
* "[error] Premature end of script headers: ..."
*/
if (!(prg_info.st_mode & S_IXUSR)) {
log_err("file has no execute permission: (%s/%s)\n", cwd, cmd);
exit(121);
}
#ifdef AP_SUEXEC_UMASK
/*
* umask() uses inverse logic; bits are CLEAR for allowed access.
*/
if ((~AP_SUEXEC_UMASK) & 0022) {
log_err("notice: AP_SUEXEC_UMASK of %03o allows "
"write permission to group and/or other\n", AP_SUEXEC_UMASK);
}
umask(AP_SUEXEC_UMASK);
#endif /* AP_SUEXEC_UMASK */
clean_env();
/*
* Be sure to close the log file so the CGI can't
* mess with it. If the exec fails, it will be reopened
* automatically when log_err is called. Note that the log
* might not actually be open if AP_LOG_EXEC isn't defined.
* However, the "log" cell isn't ifdef'd so let's be defensive
* and assume someone might have done something with it
* outside an ifdef'd AP_LOG_EXEC block.
*/
if (log != NULL) {
fclose(log);
log = NULL;
}
/*
* Execute the command, replacing our image with its own.
*/
#ifdef NEED_HASHBANG_EMUL
/* We need the #! emulation when we want to execute scripts */
{
extern char **environ;
ap_execve(cmd, &argv[3], environ);
}
#else /*NEED_HASHBANG_EMUL*/
execv(cmd, &argv[3]);
#endif /*NEED_HASHBANG_EMUL*/
/*
* (I can't help myself...sorry.)
*
* Uh oh. Still here. Where's the kaboom? There was supposed to be an
* EARTH-shattering kaboom!
*
* Oh well, log the failure and error out.
*/
log_err("(%d)%s: exec failed (%s)\n", errno, strerror(errno), cmd);
exit(255);
}
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