| /* Copyright (c) 2012 The Chromium OS Authors. All rights reserved. |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include <dlfcn.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <unistd.h> |
| |
| #include "libminijail.h" |
| #include "libsyscalls.h" |
| |
| #include "elfparse.h" |
| #include "util.h" |
| |
| static void set_user(struct minijail *j, const char *arg) |
| { |
| char *end = NULL; |
| int uid = strtod(arg, &end); |
| if (!*end && *arg) { |
| minijail_change_uid(j, uid); |
| return; |
| } |
| |
| if (minijail_change_user(j, arg)) { |
| fprintf(stderr, "Bad user: '%s'\n", arg); |
| exit(1); |
| } |
| } |
| |
| static void set_group(struct minijail *j, const char *arg) |
| { |
| char *end = NULL; |
| int gid = strtod(arg, &end); |
| if (!*end && *arg) { |
| minijail_change_gid(j, gid); |
| return; |
| } |
| |
| if (minijail_change_group(j, arg)) { |
| fprintf(stderr, "Bad group: '%s'\n", arg); |
| exit(1); |
| } |
| } |
| |
| static void use_caps(struct minijail *j, const char *arg) |
| { |
| uint64_t caps; |
| char *end = NULL; |
| caps = strtoull(arg, &end, 16); |
| if (*end) { |
| fprintf(stderr, "Invalid cap set: '%s'\n", arg); |
| exit(1); |
| } |
| minijail_use_caps(j, caps); |
| } |
| |
| static void add_binding(struct minijail *j, char *arg) |
| { |
| char *src = strtok(arg, ","); |
| char *dest = strtok(NULL, ","); |
| char *flags = strtok(NULL, ","); |
| if (!src || !dest) { |
| fprintf(stderr, "Bad binding: %s %s\n", src, dest); |
| exit(1); |
| } |
| if (minijail_bind(j, src, dest, flags ? atoi(flags) : 0)) { |
| fprintf(stderr, "Bind failure.\n"); |
| exit(1); |
| } |
| } |
| |
| static void add_mount(struct minijail *j, char *arg) |
| { |
| char *src = strtok(arg, ","); |
| char *dest = strtok(NULL, ","); |
| char *type = strtok(NULL, ","); |
| char *flags = strtok(NULL, ","); |
| if (!src || !dest || !type) { |
| fprintf(stderr, "Bad mount: %s %s %s\n", src, dest, type); |
| exit(1); |
| } |
| if (minijail_mount(j, src, dest, type, |
| flags ? strtoul(flags, NULL, 16) : 0)) { |
| fprintf(stderr, "minijail_mount failed.\n"); |
| exit(1); |
| } |
| } |
| |
| static void usage(const char *progn) |
| { |
| size_t i; |
| |
| printf("Usage: %s [-GhiInprsvtUl] [-b <src>,<dest>[,<writeable>]] [-f <file>]" |
| "[-c <caps>] [-C <dir>] [-g <group>] [-S <file>] [-u <user>] " |
| "[-k <src>,<dest>,<type>[,<flags>]] " |
| "[-m \"<uid> <loweruid> <count>[,<uid> <loweruid> <count>]\"] " |
| "[-M \"<gid> <lowergid> <count>[,<uid> <loweruid> <count>]\"] " |
| "<program> [args...]\n" |
| " -a <table>: use alternate syscall table <table>\n" |
| " -b: binds <src> to <dest> in chroot. Multiple " |
| "instances allowed\n" |
| " -k: mount <src> to <dest> in chroot. Multiple " |
| "instances allowed, flags are passed to mount(2)\n" |
| " -c <caps>: restrict caps to <caps>\n" |
| " -C <dir>: chroot to <dir>\n" |
| " Not compatible with -P\n" |
| " -e[file]: enter new network namespace, or existing one if 'file' is provided\n" |
| " -f <file>: write the pid of the jailed process to <file>\n" |
| " -G: inherit secondary groups from uid\n" |
| " -g <group>: change gid to <group>\n" |
| " -h: help (this message)\n" |
| " -H: seccomp filter help message\n" |
| " -i: exit immediately after fork (do not act as init)\n" |
| " Not compatible with -p\n" |
| " -I: run <program> as init (pid 1) inside a new pid namespace (implies -p)\n" |
| " -l: enter new IPC namespace\n" |
| " -L: report blocked syscalls to syslog when using seccomp filter.\n" |
| " Forces the following syscalls to be allowed:\n" |
| " ", progn); |
| for (i = 0; i < log_syscalls_len; i++) |
| printf("%s ", log_syscalls[i]); |
| |
| printf("\n" |
| " -m: set the uid mapping of a user namespace (implies -pU).\n" |
| " Same arguments as newuidmap(1), multiple mappings should be separated by ',' (comma).\n" |
| " Not compatible with -b without writable\n" |
| " -M: set the gid mapping of a user namespace (implies -pU).\n" |
| " Same arguments as newgidmap(1), multiple mappings should be separated by ',' (comma).\n" |
| " Not compatible with -b without writable\n" |
| " -n: set no_new_privs\n" |
| " -p: enter new pid namespace (implies -vr)\n" |
| " -P <dir>: pivot_root to <dir> (implies -v)\n" |
| " Not compatible with -C\n" |
| " -r: remount /proc read-only (implies -v)\n" |
| " -s: use seccomp\n" |
| " -S <file>: set seccomp filter using <file>\n" |
| " E.g., -S /usr/share/filters/<prog>.$(uname -m)\n" |
| " Requires -n when not running as root\n" |
| " -t: mount tmpfs at /tmp inside chroot\n" |
| " -u <user>: change uid to <user>\n" |
| " -U enter new user namespace (implies -p)\n" |
| " -v: enter new mount namespace\n" |
| " -V <file>: enter specified mount namespace\n"); |
| } |
| |
| static void seccomp_filter_usage(const char *progn) |
| { |
| const struct syscall_entry *entry = syscall_table; |
| printf("Usage: %s -S <policy.file> <program> [args...]\n\n" |
| "System call names supported:\n", progn); |
| for (; entry->name && entry->nr >= 0; ++entry) |
| printf(" %s [%d]\n", entry->name, entry->nr); |
| printf("\nSee minijail0(5) for example policies.\n"); |
| } |
| |
| static int parse_args(struct minijail *j, int argc, char *argv[], |
| int *exit_immediately) |
| { |
| int opt; |
| int use_seccomp_filter = 0; |
| int pivot_root = 0, chroot = 0; |
| const size_t path_max = 4096; |
| const char *filter_path; |
| if (argc > 1 && argv[1][0] != '-') |
| return 1; |
| while ((opt = getopt(argc, argv, |
| "u:g:sS:c:C:P:b:V:f:m:M:k:a:e::vrGhHinplLtIU")) |
| != -1) { |
| switch (opt) { |
| case 'u': |
| set_user(j, optarg); |
| break; |
| case 'g': |
| set_group(j, optarg); |
| break; |
| case 'n': |
| minijail_no_new_privs(j); |
| break; |
| case 's': |
| minijail_use_seccomp(j); |
| break; |
| case 'S': |
| minijail_use_seccomp_filter(j); |
| if (strlen(optarg) >= path_max) { |
| fprintf(stderr, |
| "Filter path is too long.\n"); |
| exit(1); |
| } |
| filter_path = strndup(optarg, path_max); |
| if (!filter_path) { |
| fprintf(stderr, |
| "Could not strndup(3) filter path.\n"); |
| exit(1); |
| } |
| use_seccomp_filter = 1; |
| break; |
| case 'l': |
| minijail_namespace_ipc(j); |
| break; |
| case 'L': |
| minijail_log_seccomp_filter_failures(j); |
| break; |
| case 'b': |
| add_binding(j, optarg); |
| break; |
| case 'c': |
| use_caps(j, optarg); |
| break; |
| case 'C': |
| if (pivot_root) { |
| fprintf(stderr, "Could not set chroot because " |
| "'-P' was specified.\n"); |
| exit(1); |
| } |
| if (0 != minijail_enter_chroot(j, optarg)) { |
| fprintf(stderr, "Could not set chroot.\n"); |
| exit(1); |
| } |
| chroot = 1; |
| break; |
| case 'k': |
| add_mount(j, optarg); |
| break; |
| case 'P': |
| if (chroot) { |
| fprintf(stderr, "Could not set pivot_root because " |
| "'-C' was specified.\n"); |
| exit(1); |
| } |
| if (0 != minijail_enter_pivot_root(j, optarg)) { |
| fprintf(stderr, "Could not set pivot_root.\n"); |
| exit(1); |
| } |
| minijail_namespace_vfs(j); |
| pivot_root = 1; |
| break; |
| case 'f': |
| if (0 != minijail_write_pid_file(j, optarg)) { |
| fprintf(stderr, "Could not prepare pid file path.\n"); |
| exit(1); |
| } |
| break; |
| case 't': |
| minijail_mount_tmp(j); |
| break; |
| case 'v': |
| minijail_namespace_vfs(j); |
| break; |
| case 'V': |
| minijail_namespace_enter_vfs(j, optarg); |
| break; |
| case 'r': |
| minijail_remount_proc_readonly(j); |
| break; |
| case 'G': |
| minijail_inherit_usergroups(j); |
| break; |
| case 'p': |
| minijail_namespace_pids(j); |
| break; |
| case 'e': |
| if (optarg) |
| minijail_namespace_enter_net(j, optarg); |
| else |
| minijail_namespace_net(j); |
| break; |
| case 'i': |
| *exit_immediately = 1; |
| break; |
| case 'H': |
| seccomp_filter_usage(argv[0]); |
| exit(1); |
| case 'I': |
| minijail_namespace_pids(j); |
| minijail_run_as_init(j); |
| break; |
| case 'U': |
| minijail_namespace_user(j); |
| minijail_namespace_pids(j); |
| break; |
| case 'm': |
| minijail_namespace_user(j); |
| minijail_namespace_pids(j); |
| if (0 != minijail_uidmap(j, optarg)) { |
| fprintf(stderr, "Could not set uidmap\n"); |
| exit(1); |
| } |
| break; |
| case 'M': |
| minijail_namespace_user(j); |
| minijail_namespace_pids(j); |
| if (0 != minijail_gidmap(j, optarg)) { |
| fprintf(stderr, "Could not set gidmap\n"); |
| exit(1); |
| } |
| break; |
| case 'a': |
| if (0 != minijail_use_alt_syscall(j, optarg)) { |
| fprintf(stderr, "Could not set alt-syscall table\n"); |
| exit(1); |
| } |
| break; |
| default: |
| usage(argv[0]); |
| exit(1); |
| } |
| if (optind < argc && argv[optind][0] != '-') |
| break; |
| } |
| |
| /* |
| * We parse seccomp filters here to make sure we've collected all |
| * cmdline options. |
| */ |
| if (use_seccomp_filter) { |
| minijail_parse_seccomp_filters(j, filter_path); |
| free((void*)filter_path); |
| } |
| |
| if (argc == optind) { |
| usage(argv[0]); |
| exit(1); |
| } |
| |
| return optind; |
| } |
| |
| int main(int argc, char *argv[]) |
| { |
| struct minijail *j = minijail_new(); |
| char *dl_mesg = NULL; |
| int exit_immediately = 0; |
| char *program_path; |
| int consumed = parse_args(j, argc, argv, &exit_immediately); |
| ElfType elftype = ELFERROR; |
| argc -= consumed; |
| argv += consumed; |
| |
| /* Get the path to the program adjusted for changing root. */ |
| program_path = minijail_get_original_path(j, argv[0]); |
| |
| /* Check that we can access the target program. */ |
| if (access(program_path, X_OK)) { |
| fprintf(stderr, "Target program '%s' is not accessible.\n", |
| argv[0]); |
| return 1; |
| } |
| |
| /* Check if target is statically or dynamically linked. */ |
| elftype = get_elf_linkage(program_path); |
| if (elftype == ELFSTATIC) { |
| /* |
| * Target binary is statically linked so we cannot use |
| * libminijailpreload.so. |
| */ |
| minijail_run_no_preload(j, argv[0], argv); |
| } else if (elftype == ELFDYNAMIC) { |
| /* |
| * Target binary is dynamically linked so we can |
| * inject libminijailpreload.so into it. |
| */ |
| |
| /* Check that we can dlopen() libminijailpreload.so. */ |
| if (!dlopen(PRELOADPATH, RTLD_LAZY | RTLD_LOCAL)) { |
| dl_mesg = dlerror(); |
| fprintf(stderr, "dlopen(): %s\n", dl_mesg); |
| return 1; |
| } |
| minijail_run(j, argv[0], argv); |
| } else { |
| fprintf(stderr, |
| "Target program '%s' is not a valid ELF file.\n", |
| argv[0]); |
| return 1; |
| } |
| |
| free(program_path); |
| |
| if (exit_immediately) { |
| info("not running init loop, exiting immediately"); |
| return 0; |
| } |
| return minijail_wait(j); |
| } |