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/*
* Copyright (C) 2014-2016 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/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
// return 0 if file not found, 1 if found
static int check_dir_or_file(const char *name) {
assert(name);
invalid_filename(name);
struct stat s;
char *fname;
if (asprintf(&fname, "/etc/%s", name) == -1)
errExit("asprintf");
if (arg_debug)
printf("Checking %s\n", fname);
if (stat(fname, &s) == -1) {
if (arg_debug)
printf("Warning: file %s not found.\n", fname);
return 0;
}
// dir or regular file
if (S_ISDIR(s.st_mode) || S_ISREG(s.st_mode)) {
free(fname);
return 1;
}
if (!is_link(fname)) {
free(fname);
return 1;
}
fprintf(stderr, "Error: invalid file type, %s.\n", fname);
exit(1);
}
void fs_check_etc_list(void) {
EUID_ASSERT();
if (strstr(cfg.etc_private_keep, "..")) {
fprintf(stderr, "Error: invalid private etc list\n");
exit(1);
}
char *dlist = strdup(cfg.etc_private_keep);
if (!dlist)
errExit("strdup");
// build a new list only with the files found
char *newlist = malloc(strlen(cfg.etc_private_keep) + 1);
if (!newlist)
errExit("malloc");
*newlist = '\0';
char *ptr = strtok(dlist, ",");
if (check_dir_or_file(ptr))
strcat(newlist, ptr);
while ((ptr = strtok(NULL, ",")) != NULL) {
if (check_dir_or_file(ptr)) {
strcat(newlist, ",");
strcat(newlist, ptr);
}
}
cfg.etc_private_keep = newlist;
free(dlist);
}
static void duplicate(char *fname) {
char *cmd;
// copy the file - this code assumes ETC_DIR is actually MNT_DIR/etc
if (asprintf(&cmd, "%s -a --parents /etc/%s %s", RUN_CP_COMMAND, fname, RUN_MNT_DIR) == -1)
errExit("asprintf");
if (arg_debug)
printf("%s\n", cmd);
if (system(cmd))
errExit("system cp -a --parents");
free(cmd);
fs_logger2("clone", fname);
}
void fs_private_etc_list(void) {
char *private_list = cfg.etc_private_keep;
assert(private_list);
struct stat s;
if (stat("/etc", &s) == -1) {
fprintf(stderr, "Error: cannot find user /etc directory\n");
exit(1);
}
// create /tmp/firejail/mnt/etc directory
fs_build_mnt_dir();
int rv = mkdir(RUN_ETC_DIR, 0755);
if (rv == -1)
errExit("mkdir");
if (chown(RUN_ETC_DIR, 0, 0) < 0)
errExit("chown");
if (chmod(RUN_ETC_DIR, 0755) < 0)
errExit("chmod");
// copy the list of files in the new etc directory
// using a new child process without root privileges
fs_logger_print(); // save the current log
pid_t child = fork();
if (child < 0)
errExit("fork");
if (child == 0) {
if (arg_debug)
printf("Copying files in the new etc directory:\n");
// elevate privileges - files in the new /etc directory belong to root
if (setreuid(0, 0) < 0)
errExit("setreuid");
if (setregid(0, 0) < 0)
errExit("setregid");
// copy the list of files in the new home directory
char *dlist = strdup(private_list);
if (!dlist)
errExit("strdup");
char *ptr = strtok(dlist, ",");
duplicate(ptr);
while ((ptr = strtok(NULL, ",")) != NULL)
duplicate(ptr);
free(dlist);
fs_logger_print();
exit(0);
}
// wait for the child to finish
waitpid(child, NULL, 0);
if (arg_debug)
printf("Mount-bind %s on top of /etc\n", RUN_ETC_DIR);
if (mount(RUN_ETC_DIR, "/etc", NULL, MS_BIND|MS_REC, NULL) < 0)
errExit("mount bind");
fs_logger("mount /etc");
}
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