2 * Copyright (C) 2015 John Crispin <blogic@openwrt.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU Lesser General Public License version 2.1
6 * as published by the Free Software Foundation
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
15 #include <sys/syscall.h>
17 #include <sys/utsname.h>
18 #include <sys/types.h>
19 #include <sys/syscall.h>
20 #include <sys/types.h>
21 #include <sys/mount.h>
22 #include <sys/prctl.h>
41 #include <libubox/utils.h>
42 #include <libubox/list.h>
43 #include <libubox/uloop.h>
45 #define STACK_SIZE (1024 * 1024)
46 #define OPT_ARGS "P:S:n:r:w:psuldo"
49 struct list_head list
;
56 static LIST_HEAD(extras
);
58 extern int pivot_root(const char *new_root
, const char *put_old
);
62 static char child_stack
[STACK_SIZE
];
64 static int mkdir_p(char *dir
, mode_t mask
)
66 char *l
= strrchr(dir
, '/');
74 if (mkdir_p(dir
, mask
))
79 ret
= mkdir(dir
, mask
);
80 if (ret
&& errno
== EEXIST
)
84 ERROR("mkdir failed on %s: %s\n", dir
, strerror(errno
));
89 static int mount_bind(const char *root
, const char *path
, const char *name
, int readonly
, int error
)
97 if (strstr(p
, "local"))
100 snprintf(old
, sizeof(old
), "%s/%s", path
, name
);
101 snprintf(new, sizeof(new), "%s%s", root
, p
);
105 snprintf(new, sizeof(new), "%s%s/%s", root
, p
, name
);
108 ERROR("%s does not exist\n", old
);
112 if (S_ISDIR(s
.st_mode
)) {
115 fd
= creat(new, 0644);
117 ERROR("failed to create %s: %s\n", new, strerror(errno
));
123 if (mount(old
, new, NULL
, MS_BIND
, NULL
)) {
124 ERROR("failed to mount -B %s %s: %s\n", old
, new, strerror(errno
));
128 if (readonly
&& mount(old
, new, NULL
, MS_BIND
| MS_REMOUNT
| MS_RDONLY
, NULL
)) {
129 ERROR("failed to remount ro %s: %s\n", new, strerror(errno
));
133 DEBUG("mount -B %s %s\n", old
, new);
138 static int build_jail(const char *path
)
146 if (mount("tmpfs", path
, "tmpfs", MS_NOATIME
, "mode=0755")) {
147 ERROR("tmpfs mount failed %s\n", strerror(errno
));
151 avl_for_each_element(&libraries
, l
, avl
)
152 if (mount_bind(path
, l
->path
, l
->name
, 1, -1))
155 list_for_each_entry(m
, &extras
, list
)
156 if (mount_bind(path
, m
->path
, m
->name
, m
->readonly
, 0))
162 static void _umount(const char *root
, const char *path
)
166 if (asprintf(&buf
, "%s%s", root
, path
) < 0) {
167 ERROR("failed to alloc umount buffer: %s\n", strerror(errno
));
169 DEBUG("umount %s\n", buf
);
175 static int stop_jail(const char *root
)
180 avl_for_each_element(&libraries
, l
, avl
) {
184 if (strstr(p
, "local"))
187 snprintf(path
, sizeof(path
), "%s%s/%s", root
, p
, l
->name
);
188 DEBUG("umount %s\n", path
);
192 list_for_each_entry(m
, &extras
, list
) {
195 snprintf(path
, sizeof(path
), "%s%s/%s", root
, m
->path
, m
->name
);
196 DEBUG("umount %s\n", path
);
200 _umount(root
, "/proc");
201 _umount(root
, "/sys");
203 DEBUG("umount %s\n", root
);
211 static char** build_envp(const char *seccomp
, int debug
)
213 static char *envp
[MAX_ENVP
];
214 static char preload_var
[64];
215 static char seccomp_var
[64];
216 static char debug_var
[] = "LD_DEBUG=all";
217 char *preload_lib
= find_lib("libpreload-seccomp.so");
220 if (seccomp
&& !preload_lib
) {
221 ERROR("failed to add preload-lib to env\n");
225 snprintf(seccomp_var
, sizeof(seccomp_var
), "SECCOMP_FILE=%s", seccomp
);
226 envp
[count
++] = seccomp_var
;
227 snprintf(preload_var
, sizeof(preload_var
), "LD_PRELOAD=%s", preload_lib
);
228 envp
[count
++] = preload_var
;
231 envp
[count
++] = debug_var
;
236 static int spawn(const char *path
, char **argv
, const char *seccomp
)
241 ERROR("failed to spawn %s: %s\n", *argv
, strerror(errno
));
244 char **envp
= build_envp(seccomp
, 0);
246 INFO("spawning %s\n", *argv
);
247 execve(*argv
, argv
, envp
);
248 ERROR("failed to spawn child %s: %s\n", *argv
, strerror(errno
));
255 static int usage(void)
257 fprintf(stderr
, "jail <options> -D <binary> <params ...>\n");
258 fprintf(stderr
, " -P <path>\tpath where the jail will be staged\n");
259 fprintf(stderr
, " -S <file>\tseccomp filter\n");
260 fprintf(stderr
, " -n <name>\tthe name of the jail\n");
261 fprintf(stderr
, " -r <file>\treadonly files that should be staged\n");
262 fprintf(stderr
, " -w <file>\twriteable files that should be staged\n");
263 fprintf(stderr
, " -p\t\tjail has /proc\t\n");
264 fprintf(stderr
, " -s\t\tjail has /sys\t\n");
265 fprintf(stderr
, " -l\t\tjail has /dev/log\t\n");
266 fprintf(stderr
, " -u\t\tjail has a ubus socket\t\n");
271 static int child_running
= 1;
273 static void child_process_handler(struct uloop_process
*c
, int ret
)
275 INFO("child (%d) exited: %d\n", c
->pid
, ret
);
280 struct uloop_process child_process
= {
281 .cb
= child_process_handler
,
284 static int spawn_child(void *arg
)
286 char *path
= get_current_dir_name();
287 int procfs
= 0, sysfs
= 0;
288 char *seccomp
= NULL
;
298 while ((ch
= getopt(argc
, argv
, OPT_ARGS
)) != -1) {
316 if (sethostname(optarg
, strlen(optarg
)))
317 ERROR("failed to sethostname: %s\n", strerror(errno
));
322 if (asprintf(&mpoint
, "%s/old", path
) < 0) {
323 ERROR("failed to alloc pivot path: %s\n", strerror(errno
));
326 mkdir_p(mpoint
, 0755);
327 if (pivot_root(path
, mpoint
) == -1) {
328 ERROR("pivot_root failed:%s\n", strerror(errno
));
332 umount2("/old", MNT_DETACH
);
335 mkdir("/proc", 0755);
336 mount("proc", "/proc", "proc", MS_NOATIME
, 0);
340 mount("sysfs", "/sys", "sysfs", MS_NOATIME
, 0);
343 mount(NULL
, "/", NULL
, MS_RDONLY
| MS_REMOUNT
, 0);
347 child_process
.pid
= spawn(path
, &argv
[optind
], seccomp
);
348 uloop_process_add(&child_process
);
352 kill(child_process
.pid
, SIGTERM
);
353 waitpid(child_process
.pid
, NULL
, 0);
359 static int namespace_running
= 1;
361 static void namespace_process_handler(struct uloop_process
*c
, int ret
)
363 INFO("namespace (%d) exited: %d\n", c
->pid
, ret
);
365 namespace_running
= 0;
368 struct uloop_process namespace_process
= {
369 .cb
= namespace_process_handler
,
372 static void spawn_namespace(const char *path
, int argc
, char **argv
)
374 char *dir
= get_current_dir_name();
378 ERROR("failed to chdir() into the jail\n");
381 namespace_process
.pid
= clone(spawn_child
,
382 child_stack
+ STACK_SIZE
,
383 CLONE_NEWUTS
| CLONE_NEWPID
| CLONE_NEWNS
| SIGCHLD
, argv
);
385 if (namespace_process
.pid
!= -1) {
387 ERROR("failed to chdir() out of the jail\n");
389 uloop_process_add(&namespace_process
);
392 if (namespace_running
) {
393 kill(namespace_process
.pid
, SIGTERM
);
394 waitpid(namespace_process
.pid
, NULL
, 0);
397 ERROR("failed to spawn namespace: %s\n", strerror(errno
));
401 static void add_extra(char *name
, int readonly
)
406 ERROR("%s is not an absolute path\n", name
);
410 f
= calloc(1, sizeof(struct extra
));
412 f
->name
= basename(name
);
413 f
->path
= dirname(strdup(name
));
414 f
->readonly
= readonly
;
416 list_add_tail(&f
->list
, &extras
);
419 int main(int argc
, char **argv
)
421 uid_t uid
= getuid();
422 const char *name
= NULL
;
426 char log
[] = "/dev/log";
427 char ubus
[] = "/var/run/ubus.sock";
430 ERROR("not root, aborting: %s\n", strerror(errno
));
436 while ((ch
= getopt(argc
, argv
, OPT_ARGS
)) != -1) {
449 add_extra(optarg
, 1);
452 add_extra(optarg
, 0);
463 if (argc
- optind
< 1)
466 if (!path
&& asprintf(&path
, "/tmp/%s", basename(argv
[optind
])) == -1) {
467 ERROR("failed to set root path\n: %s", strerror(errno
));
471 if (!stat(path
, &s
)) {
472 ERROR("%s already exists: %s\n", path
, strerror(errno
));
477 prctl(PR_SET_NAME
, name
, NULL
, NULL
, NULL
);
479 avl_init(&libraries
, avl_strcmp
, false, NULL
);
480 alloc_library_path("/lib64");
481 alloc_library_path("/lib");
482 alloc_library_path("/usr/lib");
483 load_ldso_conf("/etc/ld.so.conf");
485 if (elf_load_deps(argv
[optind
])) {
486 ERROR("failed to load dependencies\n");
490 if (elf_load_deps("libpreload-seccomp.so")) {
491 ERROR("failed to load libpreload-seccomp.so\n");
495 ret
= build_jail(path
);
498 spawn_namespace(path
, argc
, argv
);
500 ERROR("failed to build jail\n");