X-Git-Url: http://git.archive.openwrt.org/?p=project%2Fprocd.git;a=blobdiff_plain;f=jail%2Fjail.c;h=9d7483c9fa4b8f37b9fbb0b65ce27aaa36173efe;hp=f8139b8b745504573496cba74b7c095a71d745ad;hb=cdc3dab3cd5d0295f638de3088bc4f5c9669e7c2;hpb=a4505284b4d257b490cccd77a50c9c052854e7d5

diff --git a/jail/jail.c b/jail/jail.c
index f8139b8..9d7483c 100644
--- a/jail/jail.c
+++ b/jail/jail.c
@@ -12,59 +12,45 @@
  */
 
 #define _GNU_SOURCE
-#include <sys/syscall.h>
-#include <sys/mman.h>
-#include <sys/utsname.h>
-#include <sys/types.h>
-#include <sys/syscall.h>
-#include <sys/types.h>
 #include <sys/mount.h>
 #include <sys/prctl.h>
 #include <sys/wait.h>
 
 #include <stdlib.h>
 #include <unistd.h>
-#include <values.h>
 #include <errno.h>
-#include <stdio.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <fcntl.h>
-#include <syslog.h>
 #include <libgen.h>
-#include <glob.h>
-#include <elf.h>
 #include <sched.h>
+#include <linux/limits.h>
+#include <signal.h>
 
+#include "capabilities.h"
 #include "elf.h"
+#include "fs.h"
+#include "jail.h"
+#include "log.h"
 
-#include <libubox/utils.h>
-#include <libubox/list.h>
 #include <libubox/uloop.h>
 
 #define STACK_SIZE	(1024 * 1024)
-#define OPT_ARGS	"P:S:n:r:w:d:psulo"
+#define OPT_ARGS	"S:C:n:h:r:w:d:psuloc"
 
 static struct {
-	char *path;
 	char *name;
+	char *hostname;
 	char **jail_argv;
 	char *seccomp;
+	char *capabilities;
+	int no_new_privs;
+	int namespace;
 	int procfs;
 	int ronly;
 	int sysfs;
 } opts;
 
-struct extra {
-	struct list_head list;
-
-	const char *path;
-	const char *name;
-	int readonly;
-};
-
-static LIST_HEAD(extras);
-
 extern int pivot_root(const char *new_root, const char *put_old);
 
 int debug = 0;
@@ -91,47 +77,38 @@ static int mkdir_p(char *dir, mode_t mask)
 		return 0;
 
 	if (ret)
-		ERROR("mkdir failed on %s: %s\n", dir, strerror(errno));
+		ERROR("mkdir(%s, %d) failed: %s\n", dir, mask, strerror(errno));
 
 	return ret;
 }
 
-static int mount_bind(const char *root, const char *path, const char *name, int readonly, int error)
+int mount_bind(const char *root, const char *path, int readonly, int error)
 {
-	const char *p = path;
 	struct stat s;
-	char old[256];
-	char new[256];
+	char new[PATH_MAX];
 	int fd;
 
-	if (strstr(p, "local"))
-		p = "/lib";
-
-	snprintf(old, sizeof(old), "%s/%s", path, name);
-	snprintf(new, sizeof(new), "%s%s", root, p);
-
-	mkdir_p(new, 0755);
-
-	snprintf(new, sizeof(new), "%s%s/%s", root, p, name);
-
-	if (stat(old, &s)) {
-		ERROR("%s does not exist\n", old);
+	if (stat(path, &s)) {
+		ERROR("stat(%s) failed: %s\n", path, strerror(errno));
 		return error;
 	}
 
+	snprintf(new, sizeof(new), "%s%s", root, path);
 	if (S_ISDIR(s.st_mode)) {
 		mkdir_p(new, 0755);
 	} else {
+		mkdir_p(dirname(new), 0755);
+		snprintf(new, sizeof(new), "%s%s", root, path);
 		fd = creat(new, 0644);
 		if (fd == -1) {
-			ERROR("failed to create %s: %s\n", new, strerror(errno));
+			ERROR("creat(%s) failed: %s\n", new, strerror(errno));
 			return -1;
 		}
 		close(fd);
 	}
 
-	if (mount(old, new, NULL, MS_BIND, NULL)) {
-		ERROR("failed to mount -B %s %s: %s\n", old, new, strerror(errno));
+	if (mount(path, new, NULL, MS_BIND, NULL)) {
+		ERROR("failed to mount -B %s %s: %s\n", path, new, strerror(errno));
 		return -1;
 	}
 
@@ -140,71 +117,65 @@ static int mount_bind(const char *root, const char *path, const char *name, int
 		return -1;
 	}
 
-	DEBUG("mount -B %s %s\n", old, new);
+	DEBUG("mount -B %s %s (%s)\n", path, new, readonly?"ro":"rw");
 
 	return 0;
 }
 
-static int build_jail_fs()
+static int build_jail_fs(void)
 {
-	struct library *l;
-	struct extra *m;
-
-	if (mount("tmpfs", opts.path, "tmpfs", MS_NOATIME, "mode=0755")) {
-		ERROR("tmpfs mount failed %s\n", strerror(errno));
+	char jail_root[] = "/tmp/ujail-XXXXXX";
+	if (mkdtemp(jail_root) == NULL) {
+		ERROR("mkdtemp(%s) failed: %s\n", jail_root, strerror(errno));
 		return -1;
 	}
 
-	if (chdir(opts.path)) {
-		ERROR("failed to chdir() in the jail root\n");
+	/* oldroot can't be MS_SHARED else pivot_root() fails */
+	if (mount("none", "/", NULL, MS_REC|MS_PRIVATE, NULL)) {
+		ERROR("private mount failed %s\n", strerror(errno));
 		return -1;
 	}
 
-	avl_init(&libraries, avl_strcmp, false, NULL);
-	alloc_library_path("/lib64");
-	alloc_library_path("/lib");
-	alloc_library_path("/usr/lib");
-	load_ldso_conf("/etc/ld.so.conf");
-
-	if (elf_load_deps(*opts.jail_argv)) {
-		ERROR("failed to load dependencies\n");
+	if (mount("tmpfs", jail_root, "tmpfs", MS_NOATIME, "mode=0755")) {
+		ERROR("tmpfs mount failed %s\n", strerror(errno));
 		return -1;
 	}
 
-	if (opts.seccomp && elf_load_deps("libpreload-seccomp.so")) {
-		ERROR("failed to load libpreload-seccomp.so\n");
+	if (chdir(jail_root)) {
+		ERROR("chdir(%s) (jail_root) failed: %s\n", jail_root, strerror(errno));
 		return -1;
 	}
 
-	avl_for_each_element(&libraries, l, avl)
-		if (mount_bind(opts.path, l->path, l->name, 1, -1))
-			return -1;
+	if (mount_all(jail_root)) {
+		ERROR("mount_all() failed\n");
+		return -1;
+	}
 
-	list_for_each_entry(m, &extras, list)
-		if (mount_bind(opts.path, m->path, m->name, m->readonly, 0))
-			return -1;
+	char dirbuf[sizeof(jail_root) + 4];
+	snprintf(dirbuf, sizeof(dirbuf), "%s/old", jail_root);
+	mkdir(dirbuf, 0755);
 
-	char *mpoint;
-	if (asprintf(&mpoint, "%s/old", opts.path) < 0) {
-		ERROR("failed to alloc pivot path: %s\n", strerror(errno));
+	if (pivot_root(jail_root, dirbuf) == -1) {
+		ERROR("pivot_root(%s, %s) failed: %s\n", jail_root, dirbuf, strerror(errno));
 		return -1;
 	}
-	mkdir_p(mpoint, 0755);
-	if (pivot_root(opts.path, mpoint) == -1) {
-		ERROR("pivot_root failed:%s\n", strerror(errno));
-		free(mpoint);
+	if (chdir("/")) {
+		ERROR("chdir(/) (after pivot_root) failed: %s\n", strerror(errno));
 		return -1;
 	}
-	free(mpoint);
+
+	snprintf(dirbuf, sizeof(dirbuf), "/old%s", jail_root);
+	rmdir(dirbuf);
 	umount2("/old", MNT_DETACH);
 	rmdir("/old");
+
 	if (opts.procfs) {
 		mkdir("/proc", 0755);
-		mount("proc", "/proc", "proc", MS_NOATIME, 0);
+		mount("proc", "/proc", "proc", MS_NOATIME | MS_NODEV | MS_NOEXEC | MS_NOSUID, 0);
 	}
 	if (opts.sysfs) {
 		mkdir("/sys", 0755);
-		mount("sysfs", "/sys", "sysfs", MS_NOATIME, 0);
+		mount("sysfs", "/sys", "sysfs", MS_NOATIME | MS_NODEV | MS_NOEXEC | MS_NOSUID, 0);
 	}
 	if (opts.ronly)
 		mount(NULL, "/", NULL, MS_RDONLY | MS_REMOUNT, 0);
@@ -216,10 +187,10 @@ static int build_jail_fs()
 static char** build_envp(const char *seccomp)
 {
 	static char *envp[MAX_ENVP];
-	static char preload_var[64];
-	static char seccomp_var[64];
+	static char preload_var[PATH_MAX];
+	static char seccomp_var[PATH_MAX];
 	static char debug_var[] = "LD_DEBUG=all";
-	char *preload_lib = find_lib("libpreload-seccomp.so");
+	const char *preload_lib = find_lib("libpreload-seccomp.so");
 	int count = 0;
 
 	if (seccomp && !preload_lib) {
@@ -241,12 +212,15 @@ static char** build_envp(const char *seccomp)
 static void usage(void)
 {
 	fprintf(stderr, "ujail <options> -- <binary> <params ...>\n");
-	fprintf(stderr, "  -P <path>\tpath where the jail will be staged\n");
-	fprintf(stderr, "  -S <file>\tseccomp filter\n");
+	fprintf(stderr, "  -d <num>\tshow debug log (increase num to increase verbosity)\n");
+	fprintf(stderr, "  -S <file>\tseccomp filter config\n");
+	fprintf(stderr, "  -C <file>\tcapabilities drop config\n");
+	fprintf(stderr, "  -c\t\tset PR_SET_NO_NEW_PRIVS\n");
 	fprintf(stderr, "  -n <name>\tthe name of the jail\n");
+	fprintf(stderr, "namespace jail options:\n");
+	fprintf(stderr, "  -h <hostname>\tchange the hostname of the jail\n");
 	fprintf(stderr, "  -r <file>\treadonly files that should be staged\n");
 	fprintf(stderr, "  -w <file>\twriteable files that should be staged\n");
-	fprintf(stderr, "  -d <num>\tshow debug log (increase num to increase verbosity)\n");
 	fprintf(stderr, "  -p\t\tjail has /proc\n");
 	fprintf(stderr, "  -s\t\tjail has /sys\n");
 	fprintf(stderr, "  -l\t\tjail has /dev/log\n");
@@ -255,17 +229,30 @@ static void usage(void)
 	fprintf(stderr, "\nWarning: by default root inside the jail is the same\n\
 and he has the same powers as root outside the jail,\n\
 thus he can escape the jail and/or break stuff.\n\
-Please use an appropriate seccomp filter (-S) to restrict his powers\n");
+Please use seccomp/capabilities (-S/-C) to restrict his powers\n\n\
+If you use none of the namespace jail options,\n\
+ujail will not use namespace/build a jail,\n\
+and will only drop capabilities/apply seccomp filter.\n\n");
 }
 
-static int spawn_jail(void *arg)
+static int exec_jail(void *_notused)
 {
-	if (opts.name && sethostname(opts.name, strlen(opts.name))) {
-		ERROR("failed to sethostname: %s\n", strerror(errno));
+	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: %s\n", strerror(errno));
+		exit(EXIT_FAILURE);
 	}
 
-	if (build_jail_fs()) {
-		ERROR("failed to build jail fs");
+	if (opts.namespace && opts.hostname && strlen(opts.hostname) > 0
+			&& sethostname(opts.hostname, strlen(opts.hostname))) {
+		ERROR("sethostname(%s) failed: %s\n", opts.hostname, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	if (opts.namespace && build_jail_fs()) {
+		ERROR("failed to build jail fs\n");
 		exit(EXIT_FAILURE);
 	}
 
@@ -273,12 +260,9 @@ static int spawn_jail(void *arg)
 	if (!envp)
 		exit(EXIT_FAILURE);
 
-	//TODO: drop capabilities() here
-	//prctl(PR_CAPBSET_DROP, ..., 0, 0, 0);
-
 	INFO("exec-ing %s\n", *opts.jail_argv);
 	execve(*opts.jail_argv, opts.jail_argv, envp);
-	//we get there only if execve fails
+	/* we get there only if execve fails */
 	ERROR("failed to execve %s: %s\n", *opts.jail_argv, strerror(errno));
 	exit(EXIT_FAILURE);
 }
@@ -286,8 +270,14 @@ static int spawn_jail(void *arg)
 static int jail_running = 1;
 static int jail_return_code = 0;
 
+static void jail_process_timeout_cb(struct uloop_timeout *t);
+static struct uloop_timeout jail_process_timeout = {
+	.cb = jail_process_timeout_cb,
+};
+
 static void jail_process_handler(struct uloop_process *c, int ret)
 {
+	uloop_timeout_cancel(&jail_process_timeout);
 	if (WIFEXITED(ret)) {
 		jail_return_code = WEXITSTATUS(ret);
 		INFO("jail (%d) exited with exit: %d\n", c->pid, jail_return_code);
@@ -303,31 +293,25 @@ static struct uloop_process jail_process = {
 	.cb = jail_process_handler,
 };
 
-static void add_extra(char *name, int readonly)
+static void jail_process_timeout_cb(struct uloop_timeout *t)
 {
-	struct extra *f;
-
-	if (*name != '/') {
-		ERROR("%s is not an absolute path\n", name);
-		return;
-	}
-
-	f = calloc(1, sizeof(struct extra));
-
-	f->name = basename(name);
-	f->path = dirname(strdup(name));
-	f->readonly = readonly;
+	DEBUG("jail process failed to stop, sending SIGKILL\n");
+	kill(jail_process.pid, SIGKILL);
+}
 
-	list_add_tail(&f->list, &extras);
+static void jail_handle_signal(int signo)
+{
+	DEBUG("forwarding signal %d to the jailed process\n", signo);
+	kill(jail_process.pid, signo);
 }
 
 int main(int argc, char **argv)
 {
+	sigset_t sigmask;
 	uid_t uid = getuid();
 	char log[] = "/dev/log";
 	char ubus[] = "/var/run/ubus.sock";
-	int ret = EXIT_SUCCESS;
-	int ch;
+	int ch, i;
 
 	if (uid) {
 		ERROR("not root, aborting: %s\n", strerror(errno));
@@ -335,6 +319,8 @@ int main(int argc, char **argv)
 	}
 
 	umask(022);
+	mount_list_init();
+	init_library_search();
 
 	while ((ch = getopt(argc, argv, OPT_ARGS)) != -1) {
 		switch (ch) {
@@ -342,85 +328,128 @@ int main(int argc, char **argv)
 			debug = atoi(optarg);
 			break;
 		case 'p':
+			opts.namespace = 1;
 			opts.procfs = 1;
 			break;
 		case 'o':
+			opts.namespace = 1;
 			opts.ronly = 1;
 			break;
 		case 's':
+			opts.namespace = 1;
 			opts.sysfs = 1;
 			break;
 		case 'S':
 			opts.seccomp = optarg;
-			add_extra(optarg, 1);
+			add_mount(optarg, 1, -1);
 			break;
-		case 'P':
-			opts.path = optarg;
+		case 'C':
+			opts.capabilities = optarg;
+			break;
+		case 'c':
+			opts.no_new_privs = 1;
 			break;
 		case 'n':
 			opts.name = optarg;
 			break;
+		case 'h':
+			opts.hostname = optarg;
+			break;
 		case 'r':
-			add_extra(optarg, 1);
+			opts.namespace = 1;
+			add_path_and_deps(optarg, 1, 0, 0);
 			break;
 		case 'w':
-			add_extra(optarg, 0);
+			opts.namespace = 1;
+			add_path_and_deps(optarg, 0, 0, 0);
 			break;
 		case 'u':
-			add_extra(ubus, 0);
+			opts.namespace = 1;
+			add_mount(ubus, 0, -1);
 			break;
 		case 'l':
-			add_extra(log, 0);
+			opts.namespace = 1;
+			add_mount(log, 0, -1);
 			break;
 		}
 	}
 
-	//no <binary> param found
+	/* no <binary> param found */
 	if (argc - optind < 1) {
 		usage();
 		return EXIT_FAILURE;
 	}
+	if (!(opts.namespace||opts.capabilities||opts.seccomp)) {
+		ERROR("Not using namespaces, capabilities or seccomp !!!\n\n");
+		usage();
+		return EXIT_FAILURE;
+	}
+	DEBUG("Using namespaces(%d), capabilities(%d), seccomp(%d)\n",
+		opts.namespace,
+		opts.capabilities != 0,
+		opts.seccomp != 0);
 
 	opts.jail_argv = &argv[optind];
 
+	if (opts.namespace && add_path_and_deps(*opts.jail_argv, 1, -1, 0)) {
+		ERROR("failed to load dependencies\n");
+		return -1;
+	}
+
+	if (opts.namespace && opts.seccomp && add_path_and_deps("libpreload-seccomp.so", 1, -1, 1)) {
+		ERROR("failed to load libpreload-seccomp.so\n");
+		return -1;
+	}
+
 	if (opts.name)
 		prctl(PR_SET_NAME, opts.name, NULL, NULL, NULL);
 
-	if (!opts.path && asprintf(&opts.path, "/tmp/%s", basename(*opts.jail_argv)) == -1) {
-		ERROR("failed to asprintf root path: %s\n", strerror(errno));
-		return EXIT_FAILURE;
-	}
+	uloop_init();
 
-	if (mkdir(opts.path, 0755)) {
-		ERROR("unable to create root path: %s (%s)\n", opts.path, strerror(errno));
-		return EXIT_FAILURE;
+	sigfillset(&sigmask);
+	for (i = 0; i < _NSIG; i++) {
+		struct sigaction s = { 0 };
+
+		if (!sigismember(&sigmask, i))
+			continue;
+		if ((i == SIGCHLD) || (i == SIGPIPE))
+			continue;
+
+		s.sa_handler = jail_handle_signal;
+		sigaction(i, &s, NULL);
 	}
 
-	uloop_init();
-	jail_process.pid = clone(spawn_jail,
-			child_stack + STACK_SIZE,
-			CLONE_NEWUTS | CLONE_NEWPID | CLONE_NEWNS | CLONE_NEWIPC | SIGCHLD, argv);
+	if (opts.namespace) {
+		add_mount("/dev/full", 0, -1);
+		add_mount("/dev/null", 0, -1);
+		add_mount("/dev/urandom", 0, -1);
+		add_mount("/dev/zero", 0, -1);
+
+		int flags = CLONE_NEWPID | CLONE_NEWNS | CLONE_NEWIPC | SIGCHLD;
+		if (opts.hostname)
+			flags |= CLONE_NEWUTS;
+		jail_process.pid = clone(exec_jail, child_stack + STACK_SIZE, flags, NULL);
+	} else {
+		jail_process.pid = fork();
+	}
 
-	if (jail_process.pid != -1) {
+	if (jail_process.pid > 0) {
+		/* parent process */
 		uloop_process_add(&jail_process);
 		uloop_run();
-		uloop_done();
 		if (jail_running) {
+			DEBUG("uloop interrupted, killing jail process\n");
 			kill(jail_process.pid, SIGTERM);
-			waitpid(jail_process.pid, NULL, 0);
+			uloop_timeout_set(&jail_process_timeout, 1000);
+			uloop_run();
 		}
+		uloop_done();
+		return jail_return_code;
+	} else if (jail_process.pid == 0) {
+		/* fork child process */
+		return exec_jail(NULL);
 	} else {
-		ERROR("failed to spawn namespace: %s\n", strerror(errno));
-		ret = EXIT_FAILURE;
-	}
-
-	if (rmdir(opts.path)) {
-		ERROR("Unable to remove root path: %s (%s)\n", opts.path, strerror(errno));
-		ret = EXIT_FAILURE;
+		ERROR("failed to clone/fork: %s\n", strerror(errno));
+		return EXIT_FAILURE;
 	}
-
-	if (ret)
-		return ret;
-
-	return jail_return_code;
 }