masqmail

annotate src/child.c @ 331:e507c854a63e

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Security fix! Correct handling of seteuid() return value See Debian bug #638002, reported by John Lightsey. When possible the (already available) set_euidgid() function is used. Additionally, it is unnecessary to change the identity when writing into an already open file descriptor. This should fix the problem.
author markus schnalke <meillo@marmaro.de>
date Sat, 27 Aug 2011 16:19:07 +0200
parents 98cda87105a7
children b27f66555ba8
rev   line source
meillo@0 1 /* child.c, Copyright (C) 2000 by Oliver Kurth,
meillo@0 2 *
meillo@0 3 * This program is free software; you can redistribute it and/or modify
meillo@0 4 * it under the terms of the GNU General Public License as published by
meillo@0 5 * the Free Software Foundation; either version 2 of the License, or
meillo@0 6 * (at your option) any later version.
meillo@10 7 *
meillo@0 8 * This program is distributed in the hope that it will be useful,
meillo@0 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
meillo@0 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
meillo@0 11 * GNU General Public License for more details.
meillo@0 12 *
meillo@0 13 * You should have received a copy of the GNU General Public License
meillo@0 14 * along with this program; if not, write to the Free Software
meillo@0 15 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
meillo@0 16 */
meillo@0 17
meillo@0 18 #include <errno.h>
meillo@0 19 #include <stdio.h>
meillo@0 20 #include <stdlib.h>
meillo@0 21 #include <unistd.h>
meillo@0 22 #include <signal.h>
meillo@0 23 #include <sys/types.h>
meillo@0 24 #include <sys/socket.h>
meillo@0 25 #include <syslog.h>
meillo@0 26 #include <string.h>
meillo@0 27
meillo@0 28 #include "masqmail.h"
meillo@0 29
meillo@0 30
meillo@10 31 int
meillo@10 32 child(const char *command)
meillo@0 33 {
meillo@10 34 int pipe[2];
meillo@0 35
meillo@10 36 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pipe) == 0) {
meillo@10 37 pid_t pid;
meillo@0 38
meillo@10 39 pid = fork();
meillo@10 40 if (pid == 0) {
meillo@10 41 int i, max_fd = sysconf(_SC_OPEN_MAX);
meillo@10 42 /* child */
meillo@10 43 dup2(pipe[0], 0);
meillo@10 44 dup2(pipe[0], 1);
meillo@10 45 dup2(pipe[0], 2);
meillo@0 46
meillo@10 47 if (max_fd <= 0)
meillo@10 48 max_fd = 64;
meillo@10 49 for (i = 3; i < max_fd; i++)
meillo@10 50 close(i);
meillo@10 51
meillo@10 52 {
meillo@10 53 char *argv[] = { "/bin/sh", "-c", (char *) command, NULL };
meillo@10 54 execve(*argv, argv, NULL);
meillo@10 55 }
meillo@10 56 logwrite(LOG_ALERT, "execve failed: %s\n", strerror(errno));
meillo@262 57 _exit(1);
meillo@10 58 } else if (pid == -1) {
meillo@10 59 return -1;
meillo@10 60 } else {
meillo@10 61 close(pipe[0]);
meillo@10 62 return pipe[1];
meillo@10 63 }
meillo@10 64 }
meillo@10 65 return -2;
meillo@0 66 }