118 lines
2.7 KiB
C
118 lines
2.7 KiB
C
/*
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* This file is part of ltrace.
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* Copyright (C) 2011,2012 Petr Machata, Red Hat Inc.
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* Copyright (C) 2010 Joe Damato
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* Copyright (C) 1998,1999,2003,2008,2009 Juan Cespedes
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* Copyright (C) 2006 Ian Wienand
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
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* 02110-1301 USA
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*/
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#include "config.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <errno.h>
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#include <string.h>
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#include <pwd.h>
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#include <grp.h>
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#include "backend.h"
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#include "options.h"
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#include "debug.h"
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static void
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change_uid(const char * command)
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{
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uid_t run_uid, run_euid;
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gid_t run_gid, run_egid;
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if (options.user) {
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struct passwd *pent;
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if (getuid() != 0 || geteuid() != 0) {
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fprintf(stderr,
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"you must be root to use the -u option\n");
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exit(1);
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}
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if ((pent = getpwnam(options.user)) == NULL) {
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fprintf(stderr, "cannot find user `%s'\n", options.user);
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exit(1);
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}
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run_uid = pent->pw_uid;
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run_gid = pent->pw_gid;
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if (initgroups(options.user, run_gid) < 0) {
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perror("ltrace: initgroups");
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exit(1);
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}
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} else {
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run_uid = getuid();
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run_gid = getgid();
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}
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if (options.user || !geteuid()) {
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struct stat statbuf;
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run_euid = run_uid;
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run_egid = run_gid;
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if (!stat(command, &statbuf)) {
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if (statbuf.st_mode & S_ISUID) {
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run_euid = statbuf.st_uid;
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}
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if (statbuf.st_mode & S_ISGID) {
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run_egid = statbuf.st_gid;
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}
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}
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if (setregid(run_gid, run_egid) < 0) {
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perror("ltrace: setregid");
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exit(1);
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}
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if (setreuid(run_uid, run_euid) < 0) {
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perror("ltrace: setreuid");
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exit(1);
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}
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}
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}
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pid_t
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execute_program(const char * command, char **argv)
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{
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pid_t pid;
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debug(1, "Executing `%s'...", command);
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pid = fork();
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if (pid < 0) {
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fail:
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perror("ltrace: fork");
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exit(1);
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} else if (!pid) { /* child */
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change_uid(command);
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trace_me();
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execvp(command, argv);
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fprintf(stderr, "Can't execute `%s': %s\n", command,
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strerror(errno));
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_exit(1);
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}
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if (wait_for_proc(pid) < 0)
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goto fail;
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debug(1, "PID=%d", pid);
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return pid;
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}
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