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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/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
// spoof /etc/machine_id
void fs_machineid(void) {
union machineid_t {
uint8_t u8[16];
uint32_t u32[4];
} mid;
// if --machine-id flag is inactive, do nothing
if (arg_machineid == 0)
return;
if (arg_debug)
printf("Generating a new machine-id\n");
// init random number generator
srand(time(NULL));
// generate random id
mid.u32[0] = rand();
mid.u32[1] = rand();
mid.u32[2] = rand();
mid.u32[3] = rand();
// UUID version 4 and DCE variant
mid.u8[6] = (mid.u8[6] & 0x0F) | 0x40;
mid.u8[8] = (mid.u8[8] & 0x3F) | 0x80;
// write it in a file
FILE *fp = fopen(RUN_MACHINEID, "w");
if (!fp)
errExit("fopen");
fprintf(fp, "%08x%08x%08x%08x\n", mid.u32[0], mid.u32[1], mid.u32[2], mid.u32[3]);
fclose(fp);
if (set_perms(RUN_MACHINEID, 0, 0, 0444))
errExit("set_perms");
struct stat s;
if (stat("/etc/machine-id", &s) == 0) {
if (arg_debug)
printf("installing a new /etc/machine-id\n");
if (mount(RUN_MACHINEID, "/etc/machine-id", "none", MS_BIND, "mode=444,gid=0"))
errExit("mount");
}
if (stat("/var/lib/dbus/machine-id", &s) == 0) {
if (mount(RUN_MACHINEID, "/var/lib/dbus/machine-id", "none", MS_BIND, "mode=444,gid=0"))
errExit("mount");
}
}
// return 0 if file not found, 1 if found
static int check_dir_or_file(const char *fname) {
assert(fname);
struct stat s;
if (stat(fname, &s) == -1) {
if (arg_debug)
fwarning("file %s not found.\n", fname);
return 0;
}
// read access
if (access(fname, R_OK) == -1)
goto errexit;
// dir or regular file
if (S_ISDIR(s.st_mode) || S_ISREG(s.st_mode) || !is_link(fname))
return 1; // normal exit
errexit:
fprintf(stderr, "Error: invalid file type, %s.\n", fname);
exit(1);
}
static void duplicate(const char *fname, const char *private_dir, const char *private_run_dir) {
assert(fname);
if (*fname == '~' || strchr(fname, '/') || strcmp(fname, "..") == 0) {
fprintf(stderr, "Error: \"%s\" is an invalid filename\n", fname);
exit(1);
}
invalid_filename(fname, 0); // no globbing
char *src;
if (asprintf(&src, "%s/%s", private_dir, fname) == -1)
errExit("asprintf");
if (check_dir_or_file(src) == 0) {
fwarning("skipping %s for private %s\n", fname, private_dir);
free(src);
return;
}
if (arg_debug)
printf("copying %s to private %s\n", src, private_dir);
struct stat s;
if (stat(src, &s) == 0 && S_ISDIR(s.st_mode)) {
// create the directory in RUN_ETC_DIR
char *dirname;
if (asprintf(&dirname, "%s/%s", private_run_dir, fname) == -1)
errExit("asprintf");
create_empty_dir_as_root(dirname, s.st_mode);
sbox_run(SBOX_ROOT| SBOX_SECCOMP, 3, PATH_FCOPY, src, dirname);
free(dirname);
}
else
sbox_run(SBOX_ROOT| SBOX_SECCOMP, 3, PATH_FCOPY, src, private_run_dir);
fs_logger2("clone", src);
free(src);
}
void fs_private_dir_list(const char *private_dir, const char *private_run_dir, const char *private_list) {
assert(private_dir);
assert(private_run_dir);
assert(private_list);
timetrace_start();
// create /run/firejail/mnt/etc directory
mkdir_attr(private_run_dir, 0755, 0, 0);
fs_logger2("tmpfs", private_dir);
fs_logger_print(); // save the current log
// copy the list of files in the new etc directory
// using a new child process with root privileges
if (*private_list != '\0') {
if (arg_debug)
printf("Copying files in the new %s directory:\n", private_dir);
// copy the list of files in the new home directory
char *dlist = strdup(private_list);
if (!dlist)
errExit("strdup");
char *ptr = strtok(dlist, ",");
if (!ptr) {
fprintf(stderr, "Error: invalid private %s argument\n", private_dir);
exit(1);
}
duplicate(ptr, private_dir, private_run_dir);
while ((ptr = strtok(NULL, ",")) != NULL)
duplicate(ptr, private_dir, private_run_dir);
free(dlist);
fs_logger_print();
}
if (arg_debug)
printf("Mount-bind %s on top of %s\n", private_run_dir, private_dir);
if (mount(private_run_dir, private_dir, NULL, MS_BIND|MS_REC, NULL) < 0)
errExit("mount bind");
fs_logger2("mount", private_dir);
fmessage("Private %s installed in %0.2f ms\n", private_dir, timetrace_end());
}
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