/*
- Unix SMB/Netbios implementation.
- Version 1.9.
+ Unix SMB/CIFS implementation.
run a command as a specified user
Copyright (C) Andrew Tridgell 1992-1998
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
+ the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
/* need to move this from here!! need some sleep ... */
struct current_user current_user;
-extern int DEBUGLEVEL;
-
/****************************************************************************
-This is a utility function of smbrun(). It must be called only from
-the child as it may leave the caller in a privileged state.
+This is a utility function of smbrun().
****************************************************************************/
-static BOOL setup_stdout_file(char *outfile,BOOL shared)
+
+static int setup_out_fd(void)
{
- int fd;
- SMB_STRUCT_STAT st;
- mode_t mode = S_IWUSR|S_IRUSR|S_IRGRP|S_IROTH;
- int flags = O_RDWR|O_CREAT|O_TRUNC|O_EXCL;
-
- close(1);
-
- if (shared) {
- /* become root - unprivileged users can't delete these files */
- gain_root_privilege();
- gain_root_group_privilege();
- }
-
- if(sys_stat(outfile, &st) == 0) {
- /* Check we're not deleting a device file. */
- if(st.st_mode & S_IFREG)
- unlink(outfile);
- else
- flags = O_RDWR;
- }
- /* now create the file */
- fd = sys_open(outfile,flags,mode);
-
- if (fd == -1) return False;
-
- if (fd != 1) {
- if (dup2(fd,1) != 1) {
- DEBUG(2,("Failed to create stdout file descriptor\n"));
- close(fd);
- return False;
- }
- close(fd);
- }
- return True;
-}
+ int fd;
+ pstring path;
+ slprintf(path, sizeof(path)-1, "%s/smb.XXXXXX", tmpdir());
-/****************************************************************************
-run a command being careful about uid/gid handling and putting the output in
-outfile (or discard it if outfile is NULL).
+ /* now create the file */
+ fd = smb_mkstemp(path);
+
+ if (fd == -1) {
+ DEBUG(0,("setup_out_fd: Failed to create file %s. (%s)\n",
+ path, strerror(errno) ));
+ return -1;
+ }
+
+ DEBUG(10,("setup_out_fd: Created tmp file %s\n", path ));
-if shared is True then ensure the file will be writeable by all users
-but created such that its owned by root. This overcomes a security hole.
+ /* Ensure file only kept around by open fd. */
+ unlink(path);
+ return fd;
+}
-if shared is not set then open the file with O_EXCL set
+/****************************************************************************
+run a command being careful about uid/gid handling and putting the output in
+outfd (or discard it if outfd is NULL).
****************************************************************************/
-int smbrun(char *cmd,char *outfile,BOOL shared)
+
+static int smbrun_internal(const char *cmd, int *outfd, BOOL sanitize)
{
- int fd;
pid_t pid;
- uid_t uid = current_user.uid;
- gid_t gid = current_user.gid;
+ uid_t uid = current_user.ut.uid;
+ gid_t gid = current_user.ut.gid;
/*
- * Lose any kernel oplock capabilities we may have.
+ * Lose any elevated privileges.
*/
- oplock_set_capability(False, False);
+ drop_effective_capability(KERNEL_OPLOCK_CAPABILITY);
+ drop_effective_capability(DMAPI_ACCESS_CAPABILITY);
-#ifndef HAVE_EXECL
- {
- int ret;
- pstring syscmd;
- char *path = lp_smbrun();
-
- /* in the old method we use system() to execute smbrun which then
- executes the command (using system() again!). This involves lots
- of shell launches and is very slow. It also suffers from a
- potential security hole */
- if (!file_exist(path,NULL)) {
- DEBUG(0,("SMBRUN ERROR: Can't find %s. Installation problem?\n",path));
- return(1);
- }
+ /* point our stdout at the file we want output to go into */
- slprintf(syscmd,sizeof(syscmd)-1,"%s %d %d \"(%s 2>&1) > %s\"",
- path,(int)uid,(int)gid,cmd,
- outfile?outfile:"/dev/null");
-
- DEBUG(5,("smbrun - running %s ",syscmd));
- ret = system(syscmd);
- DEBUG(5,("gave %d\n",ret));
- return(ret);
+ if (outfd && ((*outfd = setup_out_fd()) == -1)) {
+ return -1;
}
-#else
- /* in this newer method we will exec /bin/sh with the correct
+
+ /* in this method we will exec /bin/sh with the correct
arguments, after first setting stdout to point at the file */
/*
if ((pid=sys_fork()) < 0) {
DEBUG(0,("smbrun: fork failed with error %s\n", strerror(errno) ));
CatchChild();
+ if (outfd) {
+ close(*outfd);
+ *outfd = -1;
+ }
return errno;
- }
+ }
if (pid) {
/*
if (wpid != pid) {
DEBUG(2,("waitpid(%d) : %s\n",(int)pid,strerror(errno)));
+ if (outfd) {
+ close(*outfd);
+ *outfd = -1;
+ }
return -1;
}
+
+ /* Reset the seek pointer. */
+ if (outfd) {
+ sys_lseek(*outfd, 0, SEEK_SET);
+ }
+
#if defined(WIFEXITED) && defined(WEXITSTATUS)
if (WIFEXITED(status)) {
return WEXITSTATUS(status);
}
#endif
+
return status;
}
pipeline or anything else the config file specifies */
/* point our stdout at the file we want output to go into */
- if (outfile && !setup_stdout_file(outfile,shared)) {
- exit(80);
+ if (outfd) {
+ close(1);
+ if (sys_dup2(*outfd,1) != 1) {
+ DEBUG(2,("Failed to create stdout file descriptor\n"));
+ close(*outfd);
+ exit(80);
+ }
}
-
+
/* now completely lose our privileges. This is a fairly paranoid
way of doing it, but it does work on all systems that I know of */
#ifndef __INSURE__
/* close all other file descriptors, leaving only 0, 1 and 2. 0 and
2 point to /dev/null from the startup code */
+ {
+ int fd;
for (fd=3;fd<256;fd++) close(fd);
+ }
#endif
- execl("/bin/sh","sh","-c",cmd,NULL);
+ {
+ const char *newcmd = sanitize ? escape_shell_string(cmd) : cmd;
+ if (!newcmd) {
+ exit(82);
+ }
+ execl("/bin/sh","sh","-c",newcmd,NULL);
+ }
/* not reached */
- exit(82);
+ exit(83);
+ return 1;
+}
+
+/****************************************************************************
+ Use only in known safe shell calls (printing).
+****************************************************************************/
+
+int smbrun_no_sanitize(const char *cmd, int *outfd)
+{
+ return smbrun_internal(cmd, outfd, False);
+}
+
+/****************************************************************************
+ By default this now sanitizes shell expansion.
+****************************************************************************/
+
+int smbrun(const char *cmd, int *outfd)
+{
+ return smbrun_internal(cmd, outfd, True);
+}
+
+/****************************************************************************
+run a command being careful about uid/gid handling and putting the output in
+outfd (or discard it if outfd is NULL).
+sends the provided secret to the child stdin.
+****************************************************************************/
+
+int smbrunsecret(const char *cmd, const char *secret)
+{
+ pid_t pid;
+ uid_t uid = current_user.ut.uid;
+ gid_t gid = current_user.ut.gid;
+ int ifd[2];
+
+ /*
+ * Lose any elevated privileges.
+ */
+ drop_effective_capability(KERNEL_OPLOCK_CAPABILITY);
+ drop_effective_capability(DMAPI_ACCESS_CAPABILITY);
+
+ /* build up an input pipe */
+ if(pipe(ifd)) {
+ return -1;
+ }
+
+ /* in this method we will exec /bin/sh with the correct
+ arguments, after first setting stdout to point at the file */
+
+ /*
+ * We need to temporarily stop CatchChild from eating
+ * SIGCLD signals as it also eats the exit status code. JRA.
+ */
+
+ CatchChildLeaveStatus();
+
+ if ((pid=sys_fork()) < 0) {
+ DEBUG(0, ("smbrunsecret: fork failed with error %s\n", strerror(errno)));
+ CatchChild();
+ return errno;
+ }
+
+ if (pid) {
+ /*
+ * Parent.
+ */
+ int status = 0;
+ pid_t wpid;
+ size_t towrite;
+ ssize_t wrote;
+
+ close(ifd[0]);
+ /* send the secret */
+ towrite = strlen(secret);
+ wrote = write(ifd[1], secret, towrite);
+ if ( wrote != towrite ) {
+ DEBUG(0,("smbrunsecret: wrote %ld of %lu bytes\n",(long)wrote,(unsigned long)towrite));
+ }
+ fsync(ifd[1]);
+ close(ifd[1]);
+
+ /* the parent just waits for the child to exit */
+ while((wpid = sys_waitpid(pid, &status, 0)) < 0) {
+ if(errno == EINTR) {
+ errno = 0;
+ continue;
+ }
+ break;
+ }
+
+ CatchChild();
+
+ if (wpid != pid) {
+ DEBUG(2, ("waitpid(%d) : %s\n", (int)pid, strerror(errno)));
+ return -1;
+ }
+
+#if defined(WIFEXITED) && defined(WEXITSTATUS)
+ if (WIFEXITED(status)) {
+ return WEXITSTATUS(status);
+ }
+#endif
+
+ return status;
+ }
+
+ CatchChild();
+
+ /* we are in the child. we exec /bin/sh to do the work for us. we
+ don't directly exec the command we want because it may be a
+ pipeline or anything else the config file specifies */
+
+ close(ifd[1]);
+ close(0);
+ if (sys_dup2(ifd[0], 0) != 0) {
+ DEBUG(2,("Failed to create stdin file descriptor\n"));
+ close(ifd[0]);
+ exit(80);
+ }
+
+ /* now completely lose our privileges. This is a fairly paranoid
+ way of doing it, but it does work on all systems that I know of */
+
+ become_user_permanently(uid, gid);
+
+ if (getuid() != uid || geteuid() != uid ||
+ getgid() != gid || getegid() != gid) {
+ /* we failed to lose our privileges - do not execute
+ the command */
+ exit(81); /* we can't print stuff at this stage,
+ instead use exit codes for debugging */
+ }
+
+#ifndef __INSURE__
+ /* close all other file descriptors, leaving only 0, 1 and 2. 0 and
+ 2 point to /dev/null from the startup code */
+ {
+ int fd;
+ for (fd = 3; fd < 256; fd++) close(fd);
+ }
#endif
+
+ execl("/bin/sh", "sh", "-c", cmd, NULL);
+
+ /* not reached */
+ exit(82);
return 1;
}
git.samba.org / vlendec / samba-autobuild / .git / blobdiff