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/*
* Copyright (C) 2014-2018 Firejail Authors
*
* This file is part of firejail project
*
* 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
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "firejail.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
void run_symlink(int argc, char **argv, int run_as_is) {
EUID_ASSERT();
char *program = strrchr(argv[0], '/');
if (program)
program += 1;
else
program = argv[0];
if (strcmp(program, "firejail") == 0) // this is a regular "firejail program" sandbox starting
return;
// drop privileges
EUID_ROOT();
if (setgid(getgid()) < 0)
errExit("setgid/getgid");
if (setuid(getuid()) < 0)
errExit("setuid/getuid");
// find the real program by looking in PATH
char *p = getenv("PATH");
if (!p) {
fprintf(stderr, "Error: PATH environment variable not set\n");
exit(1);
}
char *path = strdup(p);
if (!path)
errExit("strdup");
char *selfpath = realpath("/proc/self/exe", NULL);
if (!selfpath)
errExit("realpath");
// look in path for our program
char *tok = strtok(path, ":");
int found = 0;
while (tok) {
char *name;
if (asprintf(&name, "%s/%s", tok, program) == -1)
errExit("asprintf");
struct stat s;
if (stat(name, &s) == 0) {
/* coverity[toctou] */
char* rp = realpath(name, NULL);
if (!rp)
errExit("realpath");
if (strcmp(selfpath, rp) != 0) {
program = strdup(name);
found = 1;
free(rp);
break;
}
free(rp);
}
free(name);
tok = strtok(NULL, ":");
}
if (!found) {
fprintf(stderr, "Error: cannot find the program in the path\n");
exit(1);
}
free(selfpath);
// restore original umask
umask(orig_umask);
// desktop integration is not supported for root user; instead, the original program is started
if (getuid() == 0 || run_as_is) {
argv[0] = program;
execv(program, argv);
exit(1);
}
// start the argv[0] program in a new sandbox
char *a[3 + argc];
a[0] =PATH_FIREJAIL;
a[1] = program;
int i;
for (i = 0; i < (argc - 1); i++) {
a[i + 2] = argv[i + 1];
}
a[i + 2] = NULL;
assert(getenv("LD_PRELOAD") == NULL);
execvp(a[0], a);
perror("execvp");
exit(1);
}
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