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/*
* Copyright (C) 2014, 2015 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>
#include <grp.h>
// check process space for kernel processes
// return 1 if found, 0 if not found
int check_kernel_procs(void) {
char *kern_proc[] = {
"kthreadd",
"ksoftirqd",
"kworker",
"rcu_sched",
"rcu_bh",
NULL // NULL terminated list
};
int i;
// look at the first 10 processes
// if a kernel process is found, return 1
for (i = 1; i <= 10; i++) {
struct stat s;
char *fname;
if (asprintf(&fname, "/proc/%d/comm", i) == -1)
errExit("asprintf");
if (stat(fname, &s) == -1) {
free(fname);
continue;
}
// open file
FILE *fp = fopen(fname, "r");
if (!fp) {
fprintf(stderr, "Warning: cannot open %s\n", fname);
free(fname);
continue;
}
// read file
char buf[100];
if (fgets(buf, 10, fp) == NULL) {
fprintf(stderr, "Warning: cannot read %s\n", fname);
fclose(fp);
free(fname);
continue;
}
// clean /n
char *ptr;
if ((ptr = strchr(buf, '\n')) != NULL)
*ptr = '\0';
// check process name against the kernel list
int j = 0;
while (kern_proc[j] != NULL) {
if (strncmp(buf, kern_proc[j], strlen(kern_proc[j])) == 0) {
fclose(fp);
free(fname);
return 1;
}
j++;
}
fclose(fp);
free(fname);
}
return 0;
}
void run_no_sandbox(int argc, char **argv) {
// drop privileges
int rv = setgroups(0, NULL); // this could fail
(void) rv;
if (setgid(getgid()) < 0)
errExit("setgid/getgid");
if (setuid(getuid()) < 0)
errExit("setuid/getuid");
// build command
char *command = NULL;
int allocated = 0;
if (argc == 1)
command = "/bin/bash";
else {
// calculate length
int len = 0;
int i;
for (i = 1; i < argc; i++) {
if (*argv[i] == '-')
continue;
break;
}
int start_index = i;
for (i = start_index; i < argc; i++)
len += strlen(argv[i]) + 1;
// allocate
command = malloc(len + 1);
if (!command)
errExit("malloc");
memset(command, 0, len + 1);
allocated = 1;
// copy
for (i = start_index; i < argc; i++) {
strcat(command, argv[i]);
strcat(command, " ");
}
}
// start the program in /bin/sh
fprintf(stderr, "Warning: an existing sandbox was detected. "
"%s will run without any additional sandboxing features in a /bin/sh shell\n", command);
rv = system(command);
(void) rv;
if (allocated)
free(command);
exit(1);
}
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