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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>
static char *paths[] = {
"/bin",
"/sbin",
"/usr/bin",
"/usr/sbin",
NULL
};
// return 1 if found, 0 if not found
static char *check_dir_or_file(const char *name) {
assert(name);
invalid_filename(name);
struct stat s;
char *fname = NULL;
int i = 0;
while (paths[i]) {
if (asprintf(&fname, "%s/%s", paths[i], name) == -1)
errExit("asprintf");
if (arg_debug)
printf("Checking %s/%s\n", paths[i], name);
if (stat(fname, &s) == 0 && !S_ISDIR(s.st_mode)) // do not allow directories
break; // file found
free(fname);
fname = NULL;
i++;
}
if (!fname) {
// fprintf(stderr, "Warning: file %s not found\n", name);
return NULL;
}
free(fname);
return paths[i];
}
void fs_check_bin_list(void) {
if (strstr(cfg.bin_private_keep, "..")) {
fprintf(stderr, "Error: invalid private bin list\n");
exit(1);
}
char *dlist = strdup(cfg.bin_private_keep);
if (!dlist)
errExit("strdup");
// create a new list removing files not found
char *newlist = malloc(strlen(dlist) + 1 + 1); // +',' + '\0'
if (!newlist)
errExit("malloc");
*newlist = '\0';
char *newlistptr = newlist;
// check the first file
char *ptr = strtok(dlist, ",");
int notfound = 0;
if (check_dir_or_file(ptr)) {
// file found, copy the name in the new list
strcpy(newlistptr, ptr);
strcat(newlistptr, ",");
newlistptr += strlen(newlistptr);
}
else
notfound = 1;
// check the rest of the list
while ((ptr = strtok(NULL, ",")) != NULL) {
if (check_dir_or_file(ptr)) {
// file found, copy the name in the new list
strcpy(newlistptr, ptr);
strcat(newlistptr, ",");
newlistptr += strlen(newlistptr);
}
else
notfound = 1;
}
if (*newlist == '\0') {
fprintf(stderr, "Warning: no --private-bin list executable found, option disabled\n");
cfg.bin_private_keep = NULL;
arg_private_bin = 0;
free(newlist);
}
else {
ptr = strrchr(newlist, ',');
assert(ptr);
*ptr = '\0';
if (notfound)
fprintf(stderr, "Warning: not all executables from --private-bin list were found. The current list is %s\n", newlist);
cfg.bin_private_keep = newlist;
}
free(dlist);
}
static void duplicate(char *fname) {
char *cmd;
char *path = check_dir_or_file(fname);
if (!path)
return;
// expand path, just in case this is a symbolic link
char *full_path;
if (asprintf(&full_path, "%s/%s", path, fname) == -1)
errExit("asprintf");
char *actual_path = realpath(full_path, NULL);
if (actual_path) {
// copy the file
if (asprintf(&cmd, "%s -a %s %s/%s", RUN_CP_COMMAND, actual_path, RUN_BIN_DIR, fname) == -1)
errExit("asprintf");
if (arg_debug)
printf("%s\n", cmd);
if (system(cmd))
errExit("system cp -a");
fs_logger2("clone", fname);
free(cmd);
free(actual_path);
}
free(full_path);
}
void fs_private_bin_list(void) {
char *private_list = cfg.bin_private_keep;
assert(private_list);
// check bin paths
int i = 0;
while (paths[i]) {
struct stat s;
if (stat(paths[i], &s) == -1) {
fprintf(stderr, "Error: cannot find %s directory\n", paths[i]);
exit(1);
}
i++;
}
// create /tmp/firejail/mnt/bin directory
fs_build_mnt_dir();
int rv = mkdir(RUN_BIN_DIR, S_IRWXU | S_IRWXG | S_IRWXO);
if (rv == -1)
errExit("mkdir");
if (chown(RUN_BIN_DIR, 0, 0) < 0)
errExit("chown");
if (chmod(RUN_BIN_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 home:\n");
// elevate privileges - files in the new /bin 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);
// moun-bind
i = 0;
while (paths[i]) {
if (arg_debug)
printf("Mount-bind %s on top of %s\n", RUN_BIN_DIR, paths[i]);
if (mount(RUN_BIN_DIR, paths[i], NULL, MS_BIND|MS_REC, NULL) < 0)
errExit("mount bind");
fs_logger2("mount", paths[i]);
i++;
}
}
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