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/*
* Copyright (C) 2014-2023 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 <glob.h>
#include <dirent.h>
#include <fcntl.h>
// build a random host name
static char *random_hostname(void) {
char vowels[] = { 'a', 'e', 'i', 'o', 'u'};
char consonants[] = {'b', 'c', 'c', 'c', 'g', 'h', 'h', 'h', 'h', 'h',
'j', 'j', 'k', 'k', 'k', 'k', 'k', 'k', 'k', 'k', 'k', 'k', 'm', 'm', 'm', 'm', 'n', 'n', 'n', 'n', 'n',
'r', 'r', 's', 's', 's', 's', 's', 's', 's', 's', 't', 't', 't', 't',
'w', 'y', 'y', 'y', 'y', 'z', 'z'};
char *ending[] = {"hiko", "hiko", "suke", "suke", "suke", "shi", "shi", "ro", "ro",
"rou", "hito", "hito","ka"};
char *name = malloc(20);
if (!name)
errExit("malloc");
int i = 0;
name[i++] = consonants[rand() % sizeof(consonants)];
name[i++] = vowels[rand() % sizeof(vowels)];
name[i++] = consonants[rand() % sizeof(consonants)];
name[i++] = vowels[rand() % sizeof(vowels)];
if (rand() % 2) {
name[i++] = consonants[rand() % sizeof(consonants)];
name[i++] = vowels[rand() % sizeof(vowels)];
}
char *ptr = ending[rand() % (sizeof(ending) / sizeof(char *))];
strcpy(name + i, ptr);
return name;
}
void fs_hostname(void) {
if (!cfg.hostname)
cfg.hostname = random_hostname();
struct stat s;
// create a new /etc/hostname
if (stat("/etc/hostname", &s) == 0) {
if (arg_debug)
printf("Creating a new /etc/hostname file\n");
create_empty_file_as_root(RUN_HOSTNAME_FILE, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
FILE *fp = fopen(RUN_HOSTNAME_FILE, "we");
if (!fp)
goto errexit;
fprintf(fp, "%s\n", cfg.hostname);
SET_PERMS_STREAM(fp, 0, 0, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
fclose(fp);
// bind-mount the file on top of /etc/hostname
if (mount(RUN_HOSTNAME_FILE, "/etc/hostname", NULL, MS_BIND|MS_REC, NULL) < 0)
errExit("mount bind /etc/hostname");
fs_logger("create /etc/hostname");
}
// create a new /etc/hosts
if (stat(RUN_HOSTS_FILE2, &s) == 0) {
if (arg_debug)
printf("Creating a new /etc/hosts file\n");
// copy /etc/host into our new file, and modify it on the fly
/* coverity[toctou] */
FILE *fp1 = fopen(RUN_HOSTS_FILE2, "re");
if (!fp1)
goto errexit;
FILE *fp2 = fopen(RUN_HOSTS_FILE, "we");
if (!fp2) {
fclose(fp1);
goto errexit;
}
char buf[4096];
int done = 0;
while (fgets(buf, sizeof(buf), fp1)) {
// remove '\n'
char *ptr = strchr(buf, '\n');
if (ptr)
*ptr = '\0';
// copy line
if (strstr(buf, "127.0.0.1") && done == 0) {
done = 1;
fprintf(fp2, "127.0.0.1 %s\n", cfg.hostname);
}
else
fprintf(fp2, "%s\n", buf);
}
fclose(fp1);
// mode and owner
SET_PERMS_STREAM(fp2, 0, 0, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
fclose(fp2);
// bind-mount the file on top of /etc/hostname
fs_mount_hosts_file();
}
return;
errexit:
fprintf(stderr, "Error: cannot create /etc/hostname and /etc/hosts files\n");
exit(1);
}
char *fs_check_hosts_file(const char *fname) {
assert(fname);
invalid_filename(fname, 0); // no globbing
char *rv = expand_macros(fname);
// the user has read access to the file
if (access(rv, R_OK))
goto errexit;
return rv;
errexit:
fprintf(stderr, "Error: invalid file %s\n", fname);
exit(1);
}
void fs_store_hosts_file(void) {
if (cfg.hosts_file)
copy_file_from_user_to_root(cfg.hosts_file, RUN_HOSTS_FILE2, 0, 0, 0644); // root needed
else
copy_file_from_user_to_root("/etc/hosts", RUN_HOSTS_FILE2, 0, 0, 0644); // root needed
}
void fs_mount_hosts_file(void) {
if (arg_debug)
printf("Loading user hosts file\n");
// check /etc/hosts file
struct stat s;
if (stat("/etc/hosts", &s) == -1)
return;
// owned by root
if (s.st_uid != 0)
goto errexit;
// bind-mount the file on top of /etc/hostname
if (mount(RUN_HOSTS_FILE, "/etc/hosts", NULL, MS_BIND|MS_REC, NULL) < 0)
errExit("mount bind /etc/hosts");
fs_logger("create /etc/hosts");
return;
errexit:
fprintf(stderr, "Error: invalid /etc/hosts file\n");
exit(1);
}
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