#include <libubus.h>
#define STACK_SIZE (1024 * 1024)
-#define OPT_ARGS "S:C:n:h:r:w:d:psulocU:G:NR:"
-
-#define NAMESPACE_MOUNT (1U << 0)
-#define NAMESPACE_IPC (1U << 1)
-#define NAMESPACE_NET (1U << 2)
-#define NAMESPACE_PID (1U << 3)
-#define NAMESPACE_USER (1U << 4)
-#define NAMESPACE_UTS (1U << 5)
-#define NAMESPACE_CGROUP (1U << 6)
+#define OPT_ARGS "S:C:n:h:r:w:d:psulocU:G:NR:fF"
static struct {
char *name;
int procfs;
int ronly;
int sysfs;
+ int pw_uid;
+ int pw_gid;
+ int gr_gid;
} opts;
+
extern int pivot_root(const char *new_root, const char *put_old);
int debug = 0;
}
if (opts.extroot) {
- if (mount(opts.extroot, jail_root, NULL, MS_BIND | MS_REC, NULL)) {
+ if (mount(opts.extroot, jail_root, NULL, MS_BIND, NULL)) {
ERROR("extroot mount failed %m\n");
return -1;
}
return -1;
}
- if (opts.namespace & NAMESPACE_NET) {
+ if (opts.namespace & CLONE_NEWNET) {
char hostdir[PATH_MAX], jailetc[PATH_MAX], jaillink[PATH_MAX];
snprintf(hostdir, PATH_MAX, "/tmp/resolv.conf-%s.d", opts.name);
return 0;
}
+static int write_uid_gid_map(pid_t child_pid, bool gidmap, int id)
+{
+ int map_file;
+ char map_path[64];
+ const char *map_format = "%d %d %d\n";
+ if (snprintf(map_path, sizeof(map_path), "/proc/%d/%s",
+ child_pid, gidmap?"gid_map":"uid_map") < 0)
+ return -1;
+
+ if ((map_file = open(map_path, O_WRONLY)) == -1)
+ return -1;
+
+ if (dprintf(map_file, map_format, 0, id, 1) == -1) {
+ close(map_file);
+ return -1;
+ }
+
+ close(map_file);
+ return 0;
+}
+
+static int write_setgroups(pid_t child_pid, bool allow)
+{
+ int setgroups_file;
+ char setgroups_path[64];
+
+ if (snprintf(setgroups_path, sizeof(setgroups_path), "/proc/%d/setgroups",
+ child_pid) < 0) {
+ return -1;
+ }
+
+ if ((setgroups_file = open(setgroups_path, O_WRONLY)) == -1) {
+ return -1;
+ }
+
+ if (dprintf(setgroups_file, allow?"allow":"deny") == -1) {
+ close(setgroups_file);
+ return -1;
+ }
+
+ close(setgroups_file);
+ return 0;
+}
+
+static void get_jail_user(int *user, int *user_gid, int *gr_gid)
+{
+ struct passwd *p = NULL;
+ struct group *g = NULL;
+
+ if (opts.user) {
+ p = getpwnam(opts.user);
+ if (!p) {
+ ERROR("failed to get uid/gid for user %s: %d (%s)\n",
+ opts.user, errno, strerror(errno));
+ exit(EXIT_FAILURE);
+ }
+ *user = p->pw_uid;
+ *user_gid = p->pw_gid;
+ } else {
+ *user = -1;
+ *user_gid = -1;
+ }
+
+ if (opts.group) {
+ g = getgrnam(opts.group);
+ if (!g) {
+ ERROR("failed to get gid for group %s: %m\n", opts.group);
+ exit(EXIT_FAILURE);
+ }
+ *gr_gid = g->gr_gid;
+ } else {
+ *gr_gid = -1;
+ }
+};
+
+static void set_jail_user(int pw_uid, int user_gid, int gr_gid)
+{
+ if ((user_gid != -1) && initgroups(opts.user, user_gid)) {
+ ERROR("failed to initgroups() for user %s: %m\n", opts.user);
+ exit(EXIT_FAILURE);
+ }
+
+ if ((gr_gid != -1) && setregid(gr_gid, gr_gid)) {
+ ERROR("failed to set group id %d: %m\n", gr_gid);
+ exit(EXIT_FAILURE);
+ }
+
+ if ((pw_uid != -1) && setreuid(pw_uid, pw_uid)) {
+ ERROR("failed to set user id %d: %m\n", pw_uid);
+ exit(EXIT_FAILURE);
+ }
+}
+
#define MAX_ENVP 8
static char** build_envp(const char *seccomp)
{
envp[count++] = preload_var;
}
- if (is_extroot)
- envp[count++] = container_var;
+ envp[count++] = container_var;
if (debug > 1)
envp[count++] = debug_var;
and will only drop capabilities/apply seccomp filter.\n\n");
}
-static int exec_jail(void *_notused)
+static int exec_jail(void *pipes_ptr)
{
- struct passwd *p = NULL;
- struct group *g = NULL;
+ int *pipes = (int*)pipes_ptr;
+ char buf[1];
+ int pw_uid, pw_gid, gr_gid;
- if (opts.capabilities && drop_capabilities(opts.capabilities))
- exit(EXIT_FAILURE);
+ close(pipes[0]);
+ close(pipes[3]);
- if (opts.no_new_privs && prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
- ERROR("prctl(PR_SET_NO_NEW_PRIVS) failed: %m\n");
+
+ buf[0] = 'i';
+ if (write(pipes[1], buf, 1) < 1) {
+ ERROR("can't write to parent\n");
exit(EXIT_FAILURE);
}
-
- if (opts.namespace && opts.hostname && strlen(opts.hostname) > 0
- && sethostname(opts.hostname, strlen(opts.hostname))) {
- ERROR("sethostname(%s) failed: %m\n", opts.hostname);
+ if (read(pipes[2], buf, 1) < 1) {
+ ERROR("can't read from parent\n");
exit(EXIT_FAILURE);
}
-
- if (opts.namespace && build_jail_fs()) {
- ERROR("failed to build jail fs\n");
+ if (buf[0] != 'O') {
+ ERROR("parent had an error, child exiting\n");
exit(EXIT_FAILURE);
}
- if (opts.user) {
- p = getpwnam(opts.user);
- if (!p) {
- ERROR("failed to get uid/gid for user %s: %d (%s)\n",
- opts.user, errno, strerror(errno));
+ close(pipes[1]);
+ close(pipes[2]);
+
+ if (opts.namespace & CLONE_NEWUSER) {
+ if (setgid(0) < 0) {
+ ERROR("setgid\n");
exit(EXIT_FAILURE);
}
- }
-
- if (opts.group) {
- g = getgrnam(opts.group);
- if (!g) {
- ERROR("failed to get gid for group %s: %m\n", opts.group);
+ if (setuid(0) < 0) {
+ ERROR("setuid\n");
exit(EXIT_FAILURE);
}
+// if (setgroups(0, NULL) < 0) {
+// ERROR("setgroups\n");
+// exit(EXIT_FAILURE);
+// }
}
- if (p && p->pw_gid && initgroups(opts.user, p->pw_gid)) {
- ERROR("failed to initgroups() for user %s: %m\n", opts.user);
+ if (opts.namespace && opts.hostname && strlen(opts.hostname) > 0
+ && sethostname(opts.hostname, strlen(opts.hostname))) {
+ ERROR("sethostname(%s) failed: %m\n", opts.hostname);
exit(EXIT_FAILURE);
}
- if (g && g->gr_gid && setgid(g->gr_gid)) {
- ERROR("failed to set group id %d: %m\n", g?g->gr_gid:p->pw_gid);
+ if (opts.namespace && build_jail_fs()) {
+ ERROR("failed to build jail fs\n");
exit(EXIT_FAILURE);
}
- if (p && p->pw_uid && setuid(p->pw_uid)) {
- ERROR("failed to set user id %d: %m\n", p->pw_uid);
+ if (opts.capabilities && drop_capabilities(opts.capabilities))
+ exit(EXIT_FAILURE);
+
+ if (opts.no_new_privs && prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
+ ERROR("prctl(PR_SET_NO_NEW_PRIVS) failed: %m\n");
exit(EXIT_FAILURE);
}
+ if (!(opts.namespace & CLONE_NEWUSER)) {
+ get_jail_user(&pw_uid, &pw_gid, &gr_gid);
+ set_jail_user(pw_uid, pw_gid, gr_gid);
+ }
char **envp = build_envp(opts.seccomp);
if (!envp)
kill(jail_process.pid, signo);
}
-static void netns_updown(bool start)
+static int netns_open_pid(const pid_t target_ns)
+{
+ char pid_net_path[PATH_MAX];
+
+ snprintf(pid_net_path, sizeof(pid_net_path), "/proc/%u/ns/net", target_ns);
+
+ return open(pid_net_path, O_RDONLY);
+}
+
+static void netns_updown(pid_t pid, bool start)
{
struct ubus_context *ctx = ubus_connect(NULL);
static struct blob_buf req;
uint32_t id;
- pid_t pid = getpid();
if (!ctx)
return;
char log[] = "/dev/log";
char ubus[] = "/var/run/ubus.sock";
int ch, i;
+ int pipes[4];
+ char sig_buf[1];
+ int netns_fd;
if (uid) {
ERROR("not root, aborting: %m\n");
debug = atoi(optarg);
break;
case 'p':
- opts.namespace |= NAMESPACE_MOUNT;
+ opts.namespace |= CLONE_NEWNS;
opts.procfs = 1;
break;
case 'o':
- opts.namespace |= NAMESPACE_MOUNT;
+ opts.namespace |= CLONE_NEWNS;
opts.ronly = 1;
break;
+ case 'f':
+ opts.namespace |= CLONE_NEWUSER;
+ break;
+ case 'F':
+ opts.namespace |= CLONE_NEWCGROUP;
+ break;
case 'R':
- opts.namespace |= NAMESPACE_MOUNT | NAMESPACE_UTS;
opts.extroot = optarg;
break;
case 's':
- opts.namespace |= NAMESPACE_MOUNT;
+ opts.namespace |= CLONE_NEWNS;
opts.sysfs = 1;
break;
case 'S':
opts.name = optarg;
break;
case 'N':
- opts.namespace |= NAMESPACE_NET;
+ opts.namespace |= CLONE_NEWNET;
break;
case 'h':
+ opts.namespace |= CLONE_NEWUTS;
opts.hostname = optarg;
break;
case 'r':
- opts.namespace |= NAMESPACE_MOUNT;
+ opts.namespace |= CLONE_NEWNS;
add_path_and_deps(optarg, 1, 0, 0);
break;
case 'w':
- opts.namespace |= NAMESPACE_MOUNT;
+ opts.namespace |= CLONE_NEWNS;
add_path_and_deps(optarg, 0, 0, 0);
break;
case 'u':
- opts.namespace |= NAMESPACE_MOUNT;
+ opts.namespace |= CLONE_NEWNS;
add_mount(ubus, 0, -1);
break;
case 'l':
- opts.namespace |= NAMESPACE_MOUNT;
+ opts.namespace |= CLONE_NEWNS;
add_mount(log, 0, -1);
break;
case 'U':
}
}
+ if (opts.namespace)
+ opts.namespace |= CLONE_NEWIPC | CLONE_NEWPID;
+
/* no <binary> param found */
if (argc - optind < 1) {
usage();
usage();
return EXIT_FAILURE;
}
- DEBUG("Using namespaces(%d), capabilities(%d), seccomp(%d)\n",
+ DEBUG("Using namespaces(0x%08x), capabilities(%d), seccomp(%d)\n",
opts.namespace,
opts.capabilities != 0,
opts.seccomp != 0);
opts.jail_argv = &argv[optind];
+ get_jail_user(&opts.pw_uid, &opts.pw_gid, &opts.gr_gid);
+
if (!opts.extroot) {
if (opts.namespace && add_path_and_deps(*opts.jail_argv, 1, -1, 0)) {
ERROR("failed to load dependencies\n");
}
if (opts.namespace) {
- int flags = SIGCHLD | CLONE_NEWPID | CLONE_NEWIPC;
-
- if (opts.namespace & NAMESPACE_MOUNT) {
- flags |= CLONE_NEWNS;
+ if (opts.namespace & CLONE_NEWNS) {
add_mount("/dev/full", 0, -1);
add_mount("/dev/null", 0, -1);
add_mount("/dev/random", 0, -1);
add_mount("/dev/zero", 0, -1);
add_mount("/dev/console", 0, -1);
- if (opts.user || opts.group) {
+ if (!opts.extroot && (opts.user || opts.group)) {
add_mount("/etc/passwd", 0, -1);
add_mount("/etc/group", 0, -1);
}
}
}
- if (opts.hostname)
- flags |= CLONE_NEWUTS;
-
- if (opts.namespace & NAMESPACE_NET) {
- unshare(CLONE_NEWNET);
- netns_updown(true);
- };
+ if (pipe(&pipes[0]) < 0 || pipe(&pipes[2]) < 0)
+ return -1;
- jail_process.pid = clone(exec_jail, child_stack + STACK_SIZE, flags, NULL);
+ jail_process.pid = clone(exec_jail, child_stack + STACK_SIZE, SIGCHLD | opts.namespace, &pipes);
} else {
jail_process.pid = fork();
}
if (jail_process.pid > 0) {
+ seteuid(0);
/* parent process */
+ close(pipes[1]);
+ close(pipes[2]);
+ if (read(pipes[0], sig_buf, 1) < 1) {
+ ERROR("can't read from child\n");
+ return -1;
+ }
+ close(pipes[0]);
+ if (opts.namespace & CLONE_NEWUSER) {
+ bool has_gr = (opts.gr_gid != -1);
+ if (write_setgroups(jail_process.pid, false)) {
+ ERROR("can't write setgroups\n");
+ return -1;
+ }
+ if (opts.pw_uid != -1) {
+ write_uid_gid_map(jail_process.pid, 0, opts.pw_uid);
+ write_uid_gid_map(jail_process.pid, 1, has_gr?opts.gr_gid:opts.pw_gid);
+ } else {
+ write_uid_gid_map(jail_process.pid, 0, 65534);
+ write_uid_gid_map(jail_process.pid, 1, has_gr?opts.gr_gid:65534);
+ }
+ }
+
+ if (opts.namespace & CLONE_NEWNET) {
+ netns_fd = netns_open_pid(jail_process.pid);
+ netns_updown(jail_process.pid, true);
+ }
+
+ sig_buf[0] = 'O';
+ if (write(pipes[3], sig_buf, 1) < 0) {
+ ERROR("can't write to child\n");
+ return -1;
+ }
+ close(pipes[3]);
uloop_process_add(&jail_process);
uloop_run();
if (jail_running) {
uloop_run();
}
uloop_done();
- if (opts.namespace & NAMESPACE_NET)
- netns_updown(false);
-
+ if (opts.namespace & CLONE_NEWNET) {
+ setns(netns_fd, CLONE_NEWNET);
+ netns_updown(getpid(), false);
+ close(netns_fd);
+ }
return jail_return_code;
} else if (jail_process.pid == 0) {
/* fork child process */
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