Jorge Lucangeli Obes | d613ab2 | 2015-03-03 14:22:50 -0800 | [diff] [blame] | 1 | /* Copyright (c) 2012 The Chromium OS Authors. All rights reserved. |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 2 | * Use of this source code is governed by a BSD-style license that can be |
Will Drewry | 32ac9f5 | 2011-08-18 21:36:27 -0500 | [diff] [blame] | 3 | * found in the LICENSE file. |
| 4 | */ |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 5 | |
| 6 | #define _BSD_SOURCE |
| 7 | #define _GNU_SOURCE |
Jorge Lucangeli Obes | c2c9bcc | 2012-05-01 09:30:24 -0700 | [diff] [blame] | 8 | |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 9 | #include <asm/unistd.h> |
Will Drewry | 32ac9f5 | 2011-08-18 21:36:27 -0500 | [diff] [blame] | 10 | #include <ctype.h> |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 11 | #include <errno.h> |
Jorge Lucangeli Obes | 1563b5b | 2014-07-10 07:01:53 -0700 | [diff] [blame] | 12 | #include <fcntl.h> |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 13 | #include <grp.h> |
| 14 | #include <inttypes.h> |
Will Drewry | fe4a372 | 2011-09-16 14:50:50 -0500 | [diff] [blame] | 15 | #include <limits.h> |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 16 | #include <linux/capability.h> |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 17 | #include <pwd.h> |
| 18 | #include <sched.h> |
| 19 | #include <signal.h> |
Will Drewry | 2f54b6a | 2011-09-16 13:45:31 -0500 | [diff] [blame] | 20 | #include <stdarg.h> |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 21 | #include <stdbool.h> |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 22 | #include <stddef.h> |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 23 | #include <stdio.h> |
| 24 | #include <stdlib.h> |
| 25 | #include <string.h> |
| 26 | #include <syscall.h> |
| 27 | #include <sys/capability.h> |
| 28 | #include <sys/mount.h> |
Will Drewry | f89aef5 | 2011-09-16 16:48:57 -0500 | [diff] [blame] | 29 | #include <sys/param.h> |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 30 | #include <sys/prctl.h> |
Jorge Lucangeli Obes | 1563b5b | 2014-07-10 07:01:53 -0700 | [diff] [blame] | 31 | #include <sys/stat.h> |
| 32 | #include <sys/types.h> |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 33 | #include <sys/user.h> |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 34 | #include <sys/wait.h> |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 35 | #include <unistd.h> |
| 36 | |
| 37 | #include "libminijail.h" |
| 38 | #include "libminijail-private.h" |
| 39 | |
Jorge Lucangeli Obes | a21c8fc | 2015-07-15 16:22:34 -0700 | [diff] [blame] | 40 | #include "signal_handler.h" |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 41 | #include "syscall_filter.h" |
Jorge Lucangeli Obes | a6b034d | 2012-08-07 15:29:20 -0700 | [diff] [blame] | 42 | #include "util.h" |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 43 | |
Lei Zhang | eee3155 | 2012-10-17 21:27:10 -0700 | [diff] [blame] | 44 | #ifdef HAVE_SECUREBITS_H |
| 45 | #include <linux/securebits.h> |
| 46 | #else |
| 47 | #define SECURE_ALL_BITS 0x15 |
| 48 | #define SECURE_ALL_LOCKS (SECURE_ALL_BITS << 1) |
| 49 | #endif |
| 50 | |
Will Drewry | 32ac9f5 | 2011-08-18 21:36:27 -0500 | [diff] [blame] | 51 | /* Until these are reliably available in linux/prctl.h */ |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 52 | #ifndef PR_SET_SECCOMP |
Jorge Lucangeli Obes | c2c9bcc | 2012-05-01 09:30:24 -0700 | [diff] [blame] | 53 | # define PR_SET_SECCOMP 22 |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 54 | #endif |
| 55 | |
Andrew Bresticker | eac2894 | 2015-11-11 16:04:46 -0800 | [diff] [blame] | 56 | #ifndef PR_ALT_SYSCALL |
| 57 | # define PR_ALT_SYSCALL 0x43724f53 |
| 58 | #endif |
| 59 | |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 60 | /* For seccomp_filter using BPF. */ |
| 61 | #ifndef PR_SET_NO_NEW_PRIVS |
| 62 | # define PR_SET_NO_NEW_PRIVS 38 |
| 63 | #endif |
| 64 | #ifndef SECCOMP_MODE_FILTER |
| 65 | # define SECCOMP_MODE_FILTER 2 /* uses user-supplied filter. */ |
Will Drewry | 32ac9f5 | 2011-08-18 21:36:27 -0500 | [diff] [blame] | 66 | #endif |
| 67 | |
Utkarsh Sanghi | 0ef8a66 | 2014-08-18 15:50:11 -0700 | [diff] [blame] | 68 | #ifdef USE_SECCOMP_SOFTFAIL |
| 69 | # define SECCOMP_SOFTFAIL 1 |
| 70 | #else |
| 71 | # define SECCOMP_SOFTFAIL 0 |
| 72 | #endif |
| 73 | |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 74 | struct mountpoint { |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 75 | char *src; |
| 76 | char *dest; |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 77 | char *type; |
| 78 | unsigned long flags; |
| 79 | struct mountpoint *next; |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 80 | }; |
| 81 | |
Will Drewry | f89aef5 | 2011-09-16 16:48:57 -0500 | [diff] [blame] | 82 | struct minijail { |
Jorge Lucangeli Obes | 4ae30cc | 2014-04-10 15:35:33 -0700 | [diff] [blame] | 83 | /* |
Jorge Lucangeli Obes | c8b21e1 | 2014-06-13 14:26:16 -0700 | [diff] [blame] | 84 | * WARNING: if you add a flag here you need to make sure it's |
| 85 | * accounted for in minijail_pre{enter|exec}() below. |
Jorge Lucangeli Obes | 4ae30cc | 2014-04-10 15:35:33 -0700 | [diff] [blame] | 86 | */ |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 87 | struct { |
| 88 | int uid:1; |
| 89 | int gid:1; |
Jorge Lucangeli Obes | d16ac49 | 2015-12-03 14:44:35 -0800 | [diff] [blame] | 90 | int usergroups:1; |
| 91 | int suppl_gids:1; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 92 | int caps:1; |
| 93 | int vfs:1; |
Jorge Lucangeli Obes | 1563b5b | 2014-07-10 07:01:53 -0700 | [diff] [blame] | 94 | int enter_vfs:1; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 95 | int pids:1; |
Dylan Reid | f794247 | 2015-11-18 17:55:26 -0800 | [diff] [blame] | 96 | int ipc:1; |
Elly Fong-Jones | 6c08630 | 2013-03-20 17:15:28 -0400 | [diff] [blame] | 97 | int net:1; |
Dylan Reid | 1102f5a | 2015-09-15 11:52:20 -0700 | [diff] [blame] | 98 | int enter_net:1; |
Yu-Hsi Chiang | 10e9123 | 2015-08-05 14:40:45 +0800 | [diff] [blame] | 99 | int userns:1; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 100 | int seccomp:1; |
Dylan Reid | 791f577 | 2015-09-14 20:02:42 -0700 | [diff] [blame] | 101 | int remount_proc_ro:1; |
Jorge Lucangeli Obes | c2c9bcc | 2012-05-01 09:30:24 -0700 | [diff] [blame] | 102 | int no_new_privs:1; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 103 | int seccomp_filter:1; |
Jorge Lucangeli Obes | bda833c | 2012-07-31 16:25:56 -0700 | [diff] [blame] | 104 | int log_seccomp_filter:1; |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 105 | int chroot:1; |
Yu-Hsi Chiang | 64d65a7 | 2015-08-13 17:43:27 +0800 | [diff] [blame] | 106 | int pivot_root:1; |
Lee Campbell | 11af062 | 2014-05-22 12:36:04 -0700 | [diff] [blame] | 107 | int mount_tmp:1; |
Yu-Hsi Chiang | 3e954ec | 2015-07-28 16:48:14 +0800 | [diff] [blame] | 108 | int do_init:1; |
Yu-Hsi Chiang | 3cc05ea | 2015-08-11 11:23:17 +0800 | [diff] [blame] | 109 | int pid_file:1; |
Andrew Bresticker | eac2894 | 2015-11-11 16:04:46 -0800 | [diff] [blame] | 110 | int alt_syscall:1; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 111 | } flags; |
| 112 | uid_t uid; |
| 113 | gid_t gid; |
| 114 | gid_t usergid; |
| 115 | char *user; |
Jorge Lucangeli Obes | d16ac49 | 2015-12-03 14:44:35 -0800 | [diff] [blame] | 116 | size_t suppl_gid_count; |
| 117 | gid_t *suppl_gid_list; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 118 | uint64_t caps; |
| 119 | pid_t initpid; |
Jorge Lucangeli Obes | 1563b5b | 2014-07-10 07:01:53 -0700 | [diff] [blame] | 120 | int mountns_fd; |
Dylan Reid | 1102f5a | 2015-09-15 11:52:20 -0700 | [diff] [blame] | 121 | int netns_fd; |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 122 | char *chrootdir; |
Yu-Hsi Chiang | 3cc05ea | 2015-08-11 11:23:17 +0800 | [diff] [blame] | 123 | char *pid_file_path; |
Yu-Hsi Chiang | 10e9123 | 2015-08-05 14:40:45 +0800 | [diff] [blame] | 124 | char *uidmap; |
| 125 | char *gidmap; |
Jorge Lucangeli Obes | c2ba9f5 | 2015-12-01 07:58:10 -0800 | [diff] [blame] | 126 | size_t filter_len; |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 127 | struct sock_fprog *filter_prog; |
Jorge Lucangeli Obes | c2ba9f5 | 2015-12-01 07:58:10 -0800 | [diff] [blame] | 128 | char *alt_syscall_table; |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 129 | struct mountpoint *mounts_head; |
| 130 | struct mountpoint *mounts_tail; |
Jorge Lucangeli Obes | c2ba9f5 | 2015-12-01 07:58:10 -0800 | [diff] [blame] | 131 | size_t mounts_count; |
Will Drewry | f89aef5 | 2011-09-16 16:48:57 -0500 | [diff] [blame] | 132 | }; |
| 133 | |
Jorge Lucangeli Obes | 4ae30cc | 2014-04-10 15:35:33 -0700 | [diff] [blame] | 134 | /* |
| 135 | * Strip out flags meant for the parent. |
| 136 | * We keep things that are not inherited across execve(2) (e.g. capabilities), |
| 137 | * or are easier to set after execve(2) (e.g. seccomp filters). |
| 138 | */ |
| 139 | void minijail_preenter(struct minijail *j) |
| 140 | { |
| 141 | j->flags.vfs = 0; |
Jorge Lucangeli Obes | 1563b5b | 2014-07-10 07:01:53 -0700 | [diff] [blame] | 142 | j->flags.enter_vfs = 0; |
Dylan Reid | 791f577 | 2015-09-14 20:02:42 -0700 | [diff] [blame] | 143 | j->flags.remount_proc_ro = 0; |
Jorge Lucangeli Obes | 4ae30cc | 2014-04-10 15:35:33 -0700 | [diff] [blame] | 144 | j->flags.pids = 0; |
Yu-Hsi Chiang | 3e954ec | 2015-07-28 16:48:14 +0800 | [diff] [blame] | 145 | j->flags.do_init = 0; |
Yu-Hsi Chiang | 3cc05ea | 2015-08-11 11:23:17 +0800 | [diff] [blame] | 146 | j->flags.pid_file = 0; |
Jorge Lucangeli Obes | 4ae30cc | 2014-04-10 15:35:33 -0700 | [diff] [blame] | 147 | } |
| 148 | |
| 149 | /* |
| 150 | * Strip out flags meant for the child. |
| 151 | * We keep things that are inherited across execve(2). |
| 152 | */ |
| 153 | void minijail_preexec(struct minijail *j) |
| 154 | { |
| 155 | int vfs = j->flags.vfs; |
Jorge Lucangeli Obes | 1563b5b | 2014-07-10 07:01:53 -0700 | [diff] [blame] | 156 | int enter_vfs = j->flags.enter_vfs; |
Dylan Reid | 791f577 | 2015-09-14 20:02:42 -0700 | [diff] [blame] | 157 | int remount_proc_ro = j->flags.remount_proc_ro; |
Yu-Hsi Chiang | 10e9123 | 2015-08-05 14:40:45 +0800 | [diff] [blame] | 158 | int userns = j->flags.userns; |
Jorge Lucangeli Obes | 4ae30cc | 2014-04-10 15:35:33 -0700 | [diff] [blame] | 159 | if (j->user) |
| 160 | free(j->user); |
| 161 | j->user = NULL; |
Jorge Lucangeli Obes | e81a52f | 2015-12-04 16:05:23 -0800 | [diff] [blame] | 162 | if (j->suppl_gid_list) |
| 163 | free(j->suppl_gid_list); |
| 164 | j->suppl_gid_list = NULL; |
Jorge Lucangeli Obes | 4ae30cc | 2014-04-10 15:35:33 -0700 | [diff] [blame] | 165 | memset(&j->flags, 0, sizeof(j->flags)); |
| 166 | /* Now restore anything we meant to keep. */ |
| 167 | j->flags.vfs = vfs; |
Jorge Lucangeli Obes | 1563b5b | 2014-07-10 07:01:53 -0700 | [diff] [blame] | 168 | j->flags.enter_vfs = enter_vfs; |
Dylan Reid | 791f577 | 2015-09-14 20:02:42 -0700 | [diff] [blame] | 169 | j->flags.remount_proc_ro = remount_proc_ro; |
Yu-Hsi Chiang | 10e9123 | 2015-08-05 14:40:45 +0800 | [diff] [blame] | 170 | j->flags.userns = userns; |
Jorge Lucangeli Obes | 4ae30cc | 2014-04-10 15:35:33 -0700 | [diff] [blame] | 171 | /* Note, |pids| will already have been used before this call. */ |
| 172 | } |
| 173 | |
| 174 | /* Minijail API. */ |
| 175 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 176 | struct minijail API *minijail_new(void) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 177 | { |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 178 | return calloc(1, sizeof(struct minijail)); |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 179 | } |
| 180 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 181 | void API minijail_change_uid(struct minijail *j, uid_t uid) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 182 | { |
| 183 | if (uid == 0) |
| 184 | die("useless change to uid 0"); |
| 185 | j->uid = uid; |
| 186 | j->flags.uid = 1; |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 187 | } |
| 188 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 189 | void API minijail_change_gid(struct minijail *j, gid_t gid) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 190 | { |
| 191 | if (gid == 0) |
| 192 | die("useless change to gid 0"); |
| 193 | j->gid = gid; |
| 194 | j->flags.gid = 1; |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 195 | } |
| 196 | |
Jorge Lucangeli Obes | d16ac49 | 2015-12-03 14:44:35 -0800 | [diff] [blame] | 197 | int API minijail_set_supplementary_gids(struct minijail *j, size_t size, |
| 198 | const gid_t *list) |
| 199 | { |
Jorge Lucangeli Obes | 06940be | 2015-12-04 18:09:21 -0800 | [diff] [blame^] | 200 | size_t i; |
| 201 | |
Jorge Lucangeli Obes | d16ac49 | 2015-12-03 14:44:35 -0800 | [diff] [blame] | 202 | if (j->flags.usergroups) |
| 203 | die("cannot inherit *and* set supplementary groups"); |
| 204 | |
| 205 | if (size == 0) |
| 206 | return -EINVAL; |
| 207 | |
| 208 | /* Copy the gid_t array. */ |
| 209 | j->suppl_gid_list = calloc(size, sizeof(gid_t)); |
| 210 | if (!j->suppl_gid_list) { |
| 211 | return -ENOMEM; |
| 212 | } |
Jorge Lucangeli Obes | 06940be | 2015-12-04 18:09:21 -0800 | [diff] [blame^] | 213 | for (i = 0; i < size; i++) { |
Jorge Lucangeli Obes | d16ac49 | 2015-12-03 14:44:35 -0800 | [diff] [blame] | 214 | j->suppl_gid_list[i] = list[i]; |
| 215 | } |
| 216 | j->suppl_gid_count = size; |
| 217 | j->flags.suppl_gids = 1; |
| 218 | return 0; |
| 219 | } |
| 220 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 221 | int API minijail_change_user(struct minijail *j, const char *user) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 222 | { |
| 223 | char *buf = NULL; |
| 224 | struct passwd pw; |
| 225 | struct passwd *ppw = NULL; |
| 226 | ssize_t sz = sysconf(_SC_GETPW_R_SIZE_MAX); |
| 227 | if (sz == -1) |
| 228 | sz = 65536; /* your guess is as good as mine... */ |
Elly Jones | eb300c5 | 2011-09-22 14:35:43 -0400 | [diff] [blame] | 229 | |
Elly Jones | dd3e851 | 2012-01-23 15:13:38 -0500 | [diff] [blame] | 230 | /* |
| 231 | * sysconf(_SC_GETPW_R_SIZE_MAX), under glibc, is documented to return |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 232 | * the maximum needed size of the buffer, so we don't have to search. |
| 233 | */ |
| 234 | buf = malloc(sz); |
| 235 | if (!buf) |
| 236 | return -ENOMEM; |
| 237 | getpwnam_r(user, &pw, buf, sz, &ppw); |
Elly Jones | dd3e851 | 2012-01-23 15:13:38 -0500 | [diff] [blame] | 238 | /* |
| 239 | * We're safe to free the buffer here. The strings inside pw point |
| 240 | * inside buf, but we don't use any of them; this leaves the pointers |
| 241 | * dangling but it's safe. ppw points at pw if getpwnam_r succeeded. |
| 242 | */ |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 243 | free(buf); |
Jorge Lucangeli Obes | 4e48065 | 2014-03-26 10:56:42 -0700 | [diff] [blame] | 244 | /* getpwnam_r(3) does *not* set errno when |ppw| is NULL. */ |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 245 | if (!ppw) |
Jorge Lucangeli Obes | 4e48065 | 2014-03-26 10:56:42 -0700 | [diff] [blame] | 246 | return -1; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 247 | minijail_change_uid(j, ppw->pw_uid); |
| 248 | j->user = strdup(user); |
| 249 | if (!j->user) |
| 250 | return -ENOMEM; |
| 251 | j->usergid = ppw->pw_gid; |
| 252 | return 0; |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 253 | } |
| 254 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 255 | int API minijail_change_group(struct minijail *j, const char *group) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 256 | { |
Jorge Lucangeli Obes | a21c8fc | 2015-07-15 16:22:34 -0700 | [diff] [blame] | 257 | char *buf = NULL; |
Yabin Cui | 1b21c8f | 2015-07-22 10:34:45 -0700 | [diff] [blame] | 258 | struct group gr; |
| 259 | struct group *pgr = NULL; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 260 | ssize_t sz = sysconf(_SC_GETGR_R_SIZE_MAX); |
| 261 | if (sz == -1) |
| 262 | sz = 65536; /* and mine is as good as yours, really */ |
Elly Jones | eb300c5 | 2011-09-22 14:35:43 -0400 | [diff] [blame] | 263 | |
Elly Jones | dd3e851 | 2012-01-23 15:13:38 -0500 | [diff] [blame] | 264 | /* |
| 265 | * sysconf(_SC_GETGR_R_SIZE_MAX), under glibc, is documented to return |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 266 | * the maximum needed size of the buffer, so we don't have to search. |
| 267 | */ |
| 268 | buf = malloc(sz); |
| 269 | if (!buf) |
| 270 | return -ENOMEM; |
| 271 | getgrnam_r(group, &gr, buf, sz, &pgr); |
Elly Jones | dd3e851 | 2012-01-23 15:13:38 -0500 | [diff] [blame] | 272 | /* |
| 273 | * We're safe to free the buffer here. The strings inside gr point |
| 274 | * inside buf, but we don't use any of them; this leaves the pointers |
| 275 | * dangling but it's safe. pgr points at gr if getgrnam_r succeeded. |
| 276 | */ |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 277 | free(buf); |
Jorge Lucangeli Obes | 4e48065 | 2014-03-26 10:56:42 -0700 | [diff] [blame] | 278 | /* getgrnam_r(3) does *not* set errno when |pgr| is NULL. */ |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 279 | if (!pgr) |
Jorge Lucangeli Obes | 4e48065 | 2014-03-26 10:56:42 -0700 | [diff] [blame] | 280 | return -1; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 281 | minijail_change_gid(j, pgr->gr_gid); |
| 282 | return 0; |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 283 | } |
| 284 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 285 | void API minijail_use_seccomp(struct minijail *j) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 286 | { |
| 287 | j->flags.seccomp = 1; |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 288 | } |
| 289 | |
Jorge Lucangeli Obes | c2c9bcc | 2012-05-01 09:30:24 -0700 | [diff] [blame] | 290 | void API minijail_no_new_privs(struct minijail *j) |
| 291 | { |
| 292 | j->flags.no_new_privs = 1; |
| 293 | } |
| 294 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 295 | void API minijail_use_seccomp_filter(struct minijail *j) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 296 | { |
| 297 | j->flags.seccomp_filter = 1; |
Will Drewry | 32ac9f5 | 2011-08-18 21:36:27 -0500 | [diff] [blame] | 298 | } |
| 299 | |
Jorge Lucangeli Obes | bda833c | 2012-07-31 16:25:56 -0700 | [diff] [blame] | 300 | void API minijail_log_seccomp_filter_failures(struct minijail *j) |
| 301 | { |
| 302 | j->flags.log_seccomp_filter = 1; |
| 303 | } |
| 304 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 305 | void API minijail_use_caps(struct minijail *j, uint64_t capmask) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 306 | { |
| 307 | j->caps = capmask; |
| 308 | j->flags.caps = 1; |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 309 | } |
| 310 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 311 | void API minijail_namespace_vfs(struct minijail *j) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 312 | { |
| 313 | j->flags.vfs = 1; |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 314 | } |
| 315 | |
Jorge Lucangeli Obes | 1563b5b | 2014-07-10 07:01:53 -0700 | [diff] [blame] | 316 | void API minijail_namespace_enter_vfs(struct minijail *j, const char *ns_path) |
| 317 | { |
| 318 | int ns_fd = open(ns_path, O_RDONLY); |
| 319 | if (ns_fd < 0) { |
| 320 | pdie("failed to open namespace '%s'", ns_path); |
| 321 | } |
| 322 | j->mountns_fd = ns_fd; |
| 323 | j->flags.enter_vfs = 1; |
| 324 | } |
| 325 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 326 | void API minijail_namespace_pids(struct minijail *j) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 327 | { |
Elly Jones | e58176c | 2012-01-23 11:46:17 -0500 | [diff] [blame] | 328 | j->flags.vfs = 1; |
Dylan Reid | 791f577 | 2015-09-14 20:02:42 -0700 | [diff] [blame] | 329 | j->flags.remount_proc_ro = 1; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 330 | j->flags.pids = 1; |
Yu-Hsi Chiang | 3e954ec | 2015-07-28 16:48:14 +0800 | [diff] [blame] | 331 | j->flags.do_init = 1; |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 332 | } |
| 333 | |
Dylan Reid | f794247 | 2015-11-18 17:55:26 -0800 | [diff] [blame] | 334 | void API minijail_namespace_ipc(struct minijail *j) |
| 335 | { |
| 336 | j->flags.ipc = 1; |
| 337 | } |
| 338 | |
Elly Fong-Jones | 6c08630 | 2013-03-20 17:15:28 -0400 | [diff] [blame] | 339 | void API minijail_namespace_net(struct minijail *j) |
| 340 | { |
| 341 | j->flags.net = 1; |
| 342 | } |
| 343 | |
Dylan Reid | 1102f5a | 2015-09-15 11:52:20 -0700 | [diff] [blame] | 344 | void API minijail_namespace_enter_net(struct minijail *j, const char *ns_path) |
| 345 | { |
| 346 | int ns_fd = open(ns_path, O_RDONLY); |
| 347 | if (ns_fd < 0) { |
| 348 | pdie("failed to open namespace '%s'", ns_path); |
| 349 | } |
| 350 | j->netns_fd = ns_fd; |
| 351 | j->flags.enter_net = 1; |
| 352 | } |
| 353 | |
Dylan Reid | 791f577 | 2015-09-14 20:02:42 -0700 | [diff] [blame] | 354 | void API minijail_remount_proc_readonly(struct minijail *j) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 355 | { |
| 356 | j->flags.vfs = 1; |
Dylan Reid | 791f577 | 2015-09-14 20:02:42 -0700 | [diff] [blame] | 357 | j->flags.remount_proc_ro = 1; |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 358 | } |
| 359 | |
Yu-Hsi Chiang | 10e9123 | 2015-08-05 14:40:45 +0800 | [diff] [blame] | 360 | void API minijail_namespace_user(struct minijail *j) |
| 361 | { |
| 362 | j->flags.userns = 1; |
| 363 | } |
| 364 | |
| 365 | int API minijail_uidmap(struct minijail *j, const char *uidmap) |
| 366 | { |
| 367 | j->uidmap = strdup(uidmap); |
| 368 | if (!j->uidmap) |
| 369 | return -ENOMEM; |
Yu-Hsi Chiang | 1912c5b | 2015-08-31 18:59:49 +0800 | [diff] [blame] | 370 | char *ch; |
| 371 | for (ch = j->uidmap; *ch; ch++) { |
| 372 | if (*ch == ',') |
| 373 | *ch = '\n'; |
| 374 | } |
Yu-Hsi Chiang | 10e9123 | 2015-08-05 14:40:45 +0800 | [diff] [blame] | 375 | return 0; |
| 376 | } |
| 377 | |
| 378 | int API minijail_gidmap(struct minijail *j, const char *gidmap) |
| 379 | { |
| 380 | j->gidmap = strdup(gidmap); |
| 381 | if (!j->gidmap) |
| 382 | return -ENOMEM; |
Yu-Hsi Chiang | 1912c5b | 2015-08-31 18:59:49 +0800 | [diff] [blame] | 383 | char *ch; |
| 384 | for (ch = j->gidmap; *ch; ch++) { |
| 385 | if (*ch == ',') |
| 386 | *ch = '\n'; |
| 387 | } |
Yu-Hsi Chiang | 10e9123 | 2015-08-05 14:40:45 +0800 | [diff] [blame] | 388 | return 0; |
| 389 | } |
| 390 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 391 | void API minijail_inherit_usergroups(struct minijail *j) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 392 | { |
| 393 | j->flags.usergroups = 1; |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 394 | } |
| 395 | |
Yu-Hsi Chiang | 3e954ec | 2015-07-28 16:48:14 +0800 | [diff] [blame] | 396 | void API minijail_run_as_init(struct minijail *j) |
| 397 | { |
| 398 | /* |
| 399 | * Since the jailed program will become 'init' in the new PID namespace, |
| 400 | * Minijail does not need to fork an 'init' process. |
| 401 | */ |
| 402 | j->flags.do_init = 0; |
| 403 | } |
| 404 | |
Jorge Lucangeli Obes | c8b21e1 | 2014-06-13 14:26:16 -0700 | [diff] [blame] | 405 | int API minijail_enter_chroot(struct minijail *j, const char *dir) |
| 406 | { |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 407 | if (j->chrootdir) |
| 408 | return -EINVAL; |
| 409 | j->chrootdir = strdup(dir); |
| 410 | if (!j->chrootdir) |
| 411 | return -ENOMEM; |
| 412 | j->flags.chroot = 1; |
| 413 | return 0; |
| 414 | } |
| 415 | |
Yu-Hsi Chiang | 64d65a7 | 2015-08-13 17:43:27 +0800 | [diff] [blame] | 416 | int API minijail_enter_pivot_root(struct minijail *j, const char *dir) |
| 417 | { |
| 418 | if (j->chrootdir) |
| 419 | return -EINVAL; |
| 420 | j->chrootdir = strdup(dir); |
| 421 | if (!j->chrootdir) |
| 422 | return -ENOMEM; |
| 423 | j->flags.pivot_root = 1; |
| 424 | return 0; |
| 425 | } |
| 426 | |
Dylan Reid | a14e08d | 2015-10-22 21:05:29 -0700 | [diff] [blame] | 427 | static char *append_external_path(const char *external_path, |
| 428 | const char *path_inside_chroot) |
Dylan Reid | 08946cc | 2015-09-16 19:10:57 -0700 | [diff] [blame] | 429 | { |
Dylan Reid | a14e08d | 2015-10-22 21:05:29 -0700 | [diff] [blame] | 430 | char *path; |
Dylan Reid | 08946cc | 2015-09-16 19:10:57 -0700 | [diff] [blame] | 431 | size_t pathlen; |
| 432 | |
Dylan Reid | 08946cc | 2015-09-16 19:10:57 -0700 | [diff] [blame] | 433 | /* One extra char for '/' and one for '\0', hence + 2. */ |
Dylan Reid | a14e08d | 2015-10-22 21:05:29 -0700 | [diff] [blame] | 434 | pathlen = strlen(path_inside_chroot) + strlen(external_path) + 2; |
| 435 | path = malloc(pathlen); |
| 436 | snprintf(path, pathlen, "%s/%s", external_path, path_inside_chroot); |
Dylan Reid | 08946cc | 2015-09-16 19:10:57 -0700 | [diff] [blame] | 437 | |
Dylan Reid | a14e08d | 2015-10-22 21:05:29 -0700 | [diff] [blame] | 438 | return path; |
| 439 | } |
| 440 | |
| 441 | char API *minijail_get_original_path(struct minijail *j, |
| 442 | const char *path_inside_chroot) |
| 443 | { |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 444 | struct mountpoint *b; |
Dylan Reid | a14e08d | 2015-10-22 21:05:29 -0700 | [diff] [blame] | 445 | |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 446 | b = j->mounts_head; |
Dylan Reid | a14e08d | 2015-10-22 21:05:29 -0700 | [diff] [blame] | 447 | while (b) { |
| 448 | /* |
| 449 | * If |path_inside_chroot| is the exact destination of a |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 450 | * mount, then the original path is exactly the source of |
| 451 | * the mount. |
Dylan Reid | a14e08d | 2015-10-22 21:05:29 -0700 | [diff] [blame] | 452 | * for example: "-b /some/path/exe,/chroot/path/exe" |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 453 | * mount source = /some/path/exe, mount dest = |
| 454 | * /chroot/path/exe Then when getting the original path of |
| 455 | * "/chroot/path/exe", the source of that mount, |
| 456 | * "/some/path/exe" is what should be returned. |
Dylan Reid | a14e08d | 2015-10-22 21:05:29 -0700 | [diff] [blame] | 457 | */ |
| 458 | if (!strcmp(b->dest, path_inside_chroot)) |
| 459 | return strdup(b->src); |
| 460 | |
| 461 | /* |
| 462 | * If |path_inside_chroot| is within the destination path of a |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 463 | * mount, take the suffix of the chroot path relative to the |
| 464 | * mount destination path, and append it to the mount source |
| 465 | * path. |
Dylan Reid | a14e08d | 2015-10-22 21:05:29 -0700 | [diff] [blame] | 466 | */ |
| 467 | if (!strncmp(b->dest, path_inside_chroot, strlen(b->dest))) { |
| 468 | const char *relative_path = |
| 469 | path_inside_chroot + strlen(b->dest); |
| 470 | return append_external_path(b->src, relative_path); |
| 471 | } |
| 472 | b = b->next; |
| 473 | } |
| 474 | |
| 475 | /* If there is a chroot path, append |path_inside_chroot| to that. */ |
| 476 | if (j->chrootdir) |
| 477 | return append_external_path(j->chrootdir, path_inside_chroot); |
| 478 | |
| 479 | /* No chroot, so the path outside is the same as it is inside. */ |
| 480 | return strdup(path_inside_chroot); |
Dylan Reid | 08946cc | 2015-09-16 19:10:57 -0700 | [diff] [blame] | 481 | } |
| 482 | |
Lee Campbell | 11af062 | 2014-05-22 12:36:04 -0700 | [diff] [blame] | 483 | void API minijail_mount_tmp(struct minijail *j) |
| 484 | { |
| 485 | j->flags.mount_tmp = 1; |
| 486 | } |
| 487 | |
Yu-Hsi Chiang | 3cc05ea | 2015-08-11 11:23:17 +0800 | [diff] [blame] | 488 | int API minijail_write_pid_file(struct minijail *j, const char *path) |
| 489 | { |
| 490 | j->pid_file_path = strdup(path); |
| 491 | if (!j->pid_file_path) |
| 492 | return -ENOMEM; |
| 493 | j->flags.pid_file = 1; |
| 494 | return 0; |
| 495 | } |
| 496 | |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 497 | int API minijail_mount(struct minijail *j, const char *src, const char *dest, |
| 498 | const char *type, unsigned long flags) |
Jorge Lucangeli Obes | c8b21e1 | 2014-06-13 14:26:16 -0700 | [diff] [blame] | 499 | { |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 500 | struct mountpoint *m; |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 501 | |
| 502 | if (*dest != '/') |
| 503 | return -EINVAL; |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 504 | m = calloc(1, sizeof(*m)); |
| 505 | if (!m) |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 506 | return -ENOMEM; |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 507 | m->dest = strdup(dest); |
| 508 | if (!m->dest) |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 509 | goto error; |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 510 | m->src = strdup(src); |
| 511 | if (!m->src) |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 512 | goto error; |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 513 | m->type = strdup(type); |
| 514 | if (!m->type) |
| 515 | goto error; |
| 516 | m->flags = flags; |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 517 | |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 518 | info("mount %s -> %s type %s", src, dest, type); |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 519 | |
Elly Jones | dd3e851 | 2012-01-23 15:13:38 -0500 | [diff] [blame] | 520 | /* |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 521 | * Force vfs namespacing so the mounts don't leak out into the |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 522 | * containing vfs namespace. |
| 523 | */ |
| 524 | minijail_namespace_vfs(j); |
| 525 | |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 526 | if (j->mounts_tail) |
| 527 | j->mounts_tail->next = m; |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 528 | else |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 529 | j->mounts_head = m; |
| 530 | j->mounts_tail = m; |
| 531 | j->mounts_count++; |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 532 | |
| 533 | return 0; |
| 534 | |
| 535 | error: |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 536 | free(m->src); |
| 537 | free(m->dest); |
| 538 | free(m); |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 539 | return -ENOMEM; |
| 540 | } |
| 541 | |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 542 | int API minijail_bind(struct minijail *j, const char *src, const char *dest, |
| 543 | int writeable) |
| 544 | { |
| 545 | unsigned long flags = MS_BIND; |
| 546 | |
| 547 | if (!writeable) |
| 548 | flags |= MS_RDONLY; |
| 549 | |
| 550 | return minijail_mount(j, src, dest, "", flags); |
| 551 | } |
| 552 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 553 | void API minijail_parse_seccomp_filters(struct minijail *j, const char *path) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 554 | { |
Utkarsh Sanghi | 0ef8a66 | 2014-08-18 15:50:11 -0700 | [diff] [blame] | 555 | if (prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, NULL)) { |
| 556 | if ((errno == ENOSYS) && SECCOMP_SOFTFAIL) { |
Jorge Lucangeli Obes | 43a6a86 | 2015-12-04 14:53:36 -0800 | [diff] [blame] | 557 | warn("not loading seccomp filter," |
| 558 | " seccomp not supported"); |
Utkarsh Sanghi | 0ef8a66 | 2014-08-18 15:50:11 -0700 | [diff] [blame] | 559 | return; |
| 560 | } |
| 561 | } |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 562 | FILE *file = fopen(path, "r"); |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 563 | if (!file) { |
Jorge Lucangeli Obes | 224e427 | 2012-08-02 14:31:39 -0700 | [diff] [blame] | 564 | pdie("failed to open seccomp filter file '%s'", path); |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 565 | } |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 566 | |
| 567 | struct sock_fprog *fprog = malloc(sizeof(struct sock_fprog)); |
Jorge Lucangeli Obes | bda833c | 2012-07-31 16:25:56 -0700 | [diff] [blame] | 568 | if (compile_filter(file, fprog, j->flags.log_seccomp_filter)) { |
| 569 | die("failed to compile seccomp filter BPF program in '%s'", |
| 570 | path); |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 571 | } |
| 572 | |
| 573 | j->filter_len = fprog->len; |
| 574 | j->filter_prog = fprog; |
| 575 | |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 576 | fclose(file); |
Will Drewry | 32ac9f5 | 2011-08-18 21:36:27 -0500 | [diff] [blame] | 577 | } |
| 578 | |
Andrew Bresticker | eac2894 | 2015-11-11 16:04:46 -0800 | [diff] [blame] | 579 | int API minijail_use_alt_syscall(struct minijail *j, const char *table) |
| 580 | { |
| 581 | j->alt_syscall_table = strdup(table); |
| 582 | if (!j->alt_syscall_table) |
| 583 | return -ENOMEM; |
| 584 | j->flags.alt_syscall = 1; |
| 585 | return 0; |
| 586 | } |
| 587 | |
Will Drewry | f89aef5 | 2011-09-16 16:48:57 -0500 | [diff] [blame] | 588 | struct marshal_state { |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 589 | size_t available; |
| 590 | size_t total; |
| 591 | char *buf; |
Will Drewry | f89aef5 | 2011-09-16 16:48:57 -0500 | [diff] [blame] | 592 | }; |
| 593 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 594 | void marshal_state_init(struct marshal_state *state, |
| 595 | char *buf, size_t available) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 596 | { |
| 597 | state->available = available; |
| 598 | state->buf = buf; |
| 599 | state->total = 0; |
Will Drewry | f89aef5 | 2011-09-16 16:48:57 -0500 | [diff] [blame] | 600 | } |
| 601 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 602 | void marshal_append(struct marshal_state *state, |
| 603 | char *src, size_t length) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 604 | { |
| 605 | size_t copy_len = MIN(state->available, length); |
Will Drewry | f89aef5 | 2011-09-16 16:48:57 -0500 | [diff] [blame] | 606 | |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 607 | /* Up to |available| will be written. */ |
| 608 | if (copy_len) { |
| 609 | memcpy(state->buf, src, copy_len); |
| 610 | state->buf += copy_len; |
| 611 | state->available -= copy_len; |
| 612 | } |
| 613 | /* |total| will contain the expected length. */ |
| 614 | state->total += length; |
Will Drewry | f89aef5 | 2011-09-16 16:48:57 -0500 | [diff] [blame] | 615 | } |
| 616 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 617 | void minijail_marshal_helper(struct marshal_state *state, |
| 618 | const struct minijail *j) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 619 | { |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 620 | struct mountpoint *m = NULL; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 621 | marshal_append(state, (char *)j, sizeof(*j)); |
| 622 | if (j->user) |
| 623 | marshal_append(state, j->user, strlen(j->user) + 1); |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 624 | if (j->chrootdir) |
| 625 | marshal_append(state, j->chrootdir, strlen(j->chrootdir) + 1); |
Andrew Bresticker | eac2894 | 2015-11-11 16:04:46 -0800 | [diff] [blame] | 626 | if (j->alt_syscall_table) { |
| 627 | marshal_append(state, j->alt_syscall_table, |
| 628 | strlen(j->alt_syscall_table) + 1); |
| 629 | } |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 630 | if (j->flags.seccomp_filter && j->filter_prog) { |
| 631 | struct sock_fprog *fp = j->filter_prog; |
| 632 | marshal_append(state, (char *)fp->filter, |
| 633 | fp->len * sizeof(struct sock_filter)); |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 634 | } |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 635 | for (m = j->mounts_head; m; m = m->next) { |
| 636 | marshal_append(state, m->src, strlen(m->src) + 1); |
| 637 | marshal_append(state, m->dest, strlen(m->dest) + 1); |
| 638 | marshal_append(state, m->type, strlen(m->type) + 1); |
| 639 | marshal_append(state, (char *)&m->flags, sizeof(m->flags)); |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 640 | } |
Will Drewry | f89aef5 | 2011-09-16 16:48:57 -0500 | [diff] [blame] | 641 | } |
| 642 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 643 | size_t API minijail_size(const struct minijail *j) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 644 | { |
| 645 | struct marshal_state state; |
| 646 | marshal_state_init(&state, NULL, 0); |
| 647 | minijail_marshal_helper(&state, j); |
| 648 | return state.total; |
Will Drewry | 2ddaad0 | 2011-09-16 11:36:08 -0500 | [diff] [blame] | 649 | } |
| 650 | |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 651 | int minijail_marshal(const struct minijail *j, char *buf, size_t available) |
| 652 | { |
| 653 | struct marshal_state state; |
| 654 | marshal_state_init(&state, buf, available); |
| 655 | minijail_marshal_helper(&state, j); |
| 656 | return (state.total > available); |
Will Drewry | 2ddaad0 | 2011-09-16 11:36:08 -0500 | [diff] [blame] | 657 | } |
| 658 | |
Jorge Lucangeli Obes | d0a6e2f | 2015-11-24 14:21:21 -0800 | [diff] [blame] | 659 | /* |
| 660 | * consumebytes: consumes @length bytes from a buffer @buf of length @buflength |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 661 | * @length Number of bytes to consume |
| 662 | * @buf Buffer to consume from |
| 663 | * @buflength Size of @buf |
| 664 | * |
| 665 | * Returns a pointer to the base of the bytes, or NULL for errors. |
| 666 | */ |
Jorge Lucangeli Obes | c8b21e1 | 2014-06-13 14:26:16 -0700 | [diff] [blame] | 667 | void *consumebytes(size_t length, char **buf, size_t *buflength) |
| 668 | { |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 669 | char *p = *buf; |
| 670 | if (length > *buflength) |
| 671 | return NULL; |
| 672 | *buf += length; |
| 673 | *buflength -= length; |
| 674 | return p; |
| 675 | } |
| 676 | |
Jorge Lucangeli Obes | d0a6e2f | 2015-11-24 14:21:21 -0800 | [diff] [blame] | 677 | /* |
| 678 | * consumestr: consumes a C string from a buffer @buf of length @length |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 679 | * @buf Buffer to consume |
| 680 | * @length Length of buffer |
| 681 | * |
| 682 | * Returns a pointer to the base of the string, or NULL for errors. |
| 683 | */ |
Jorge Lucangeli Obes | c8b21e1 | 2014-06-13 14:26:16 -0700 | [diff] [blame] | 684 | char *consumestr(char **buf, size_t *buflength) |
| 685 | { |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 686 | size_t len = strnlen(*buf, *buflength); |
| 687 | if (len == *buflength) |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 688 | /* There's no null-terminator. */ |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 689 | return NULL; |
| 690 | return consumebytes(len + 1, buf, buflength); |
| 691 | } |
| 692 | |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 693 | int minijail_unmarshal(struct minijail *j, char *serialized, size_t length) |
| 694 | { |
Jorge Lucangeli Obes | c2ba9f5 | 2015-12-01 07:58:10 -0800 | [diff] [blame] | 695 | size_t i; |
| 696 | size_t count; |
Will Drewry | bee7ba7 | 2011-10-21 20:47:01 -0500 | [diff] [blame] | 697 | int ret = -EINVAL; |
| 698 | |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 699 | if (length < sizeof(*j)) |
Will Drewry | bee7ba7 | 2011-10-21 20:47:01 -0500 | [diff] [blame] | 700 | goto out; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 701 | memcpy((void *)j, serialized, sizeof(*j)); |
| 702 | serialized += sizeof(*j); |
| 703 | length -= sizeof(*j); |
Will Drewry | f89aef5 | 2011-09-16 16:48:57 -0500 | [diff] [blame] | 704 | |
Will Drewry | bee7ba7 | 2011-10-21 20:47:01 -0500 | [diff] [blame] | 705 | /* Potentially stale pointers not used as signals. */ |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 706 | j->mounts_head = NULL; |
| 707 | j->mounts_tail = NULL; |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 708 | j->filter_prog = NULL; |
Will Drewry | bee7ba7 | 2011-10-21 20:47:01 -0500 | [diff] [blame] | 709 | |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 710 | if (j->user) { /* stale pointer */ |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 711 | char *user = consumestr(&serialized, &length); |
| 712 | if (!user) |
Will Drewry | bee7ba7 | 2011-10-21 20:47:01 -0500 | [diff] [blame] | 713 | goto clear_pointers; |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 714 | j->user = strdup(user); |
Will Drewry | bee7ba7 | 2011-10-21 20:47:01 -0500 | [diff] [blame] | 715 | if (!j->user) |
| 716 | goto clear_pointers; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 717 | } |
Will Drewry | f89aef5 | 2011-09-16 16:48:57 -0500 | [diff] [blame] | 718 | |
Elly Jones | a8d1e1b | 2011-10-21 15:38:00 -0400 | [diff] [blame] | 719 | if (j->chrootdir) { /* stale pointer */ |
| 720 | char *chrootdir = consumestr(&serialized, &length); |
| 721 | if (!chrootdir) |
Will Drewry | bee7ba7 | 2011-10-21 20:47:01 -0500 | [diff] [blame] | 722 | goto bad_chrootdir; |
Elly Jones | a8d1e1b | 2011-10-21 15:38:00 -0400 | [diff] [blame] | 723 | j->chrootdir = strdup(chrootdir); |
Will Drewry | bee7ba7 | 2011-10-21 20:47:01 -0500 | [diff] [blame] | 724 | if (!j->chrootdir) |
| 725 | goto bad_chrootdir; |
Elly Jones | a8d1e1b | 2011-10-21 15:38:00 -0400 | [diff] [blame] | 726 | } |
| 727 | |
Andrew Bresticker | eac2894 | 2015-11-11 16:04:46 -0800 | [diff] [blame] | 728 | if (j->alt_syscall_table) { /* stale pointer */ |
| 729 | char *alt_syscall_table = consumestr(&serialized, &length); |
| 730 | if (!alt_syscall_table) |
| 731 | goto bad_syscall_table; |
| 732 | j->alt_syscall_table = strdup(alt_syscall_table); |
| 733 | if (!j->alt_syscall_table) |
| 734 | goto bad_syscall_table; |
| 735 | } |
| 736 | |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 737 | if (j->flags.seccomp_filter && j->filter_len > 0) { |
| 738 | size_t ninstrs = j->filter_len; |
| 739 | if (ninstrs > (SIZE_MAX / sizeof(struct sock_filter)) || |
| 740 | ninstrs > USHRT_MAX) |
| 741 | goto bad_filters; |
| 742 | |
| 743 | size_t program_len = ninstrs * sizeof(struct sock_filter); |
| 744 | void *program = consumebytes(program_len, &serialized, &length); |
| 745 | if (!program) |
| 746 | goto bad_filters; |
| 747 | |
| 748 | j->filter_prog = malloc(sizeof(struct sock_fprog)); |
| 749 | j->filter_prog->len = ninstrs; |
| 750 | j->filter_prog->filter = malloc(program_len); |
| 751 | memcpy(j->filter_prog->filter, program, program_len); |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 752 | } |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 753 | |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 754 | count = j->mounts_count; |
| 755 | j->mounts_count = 0; |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 756 | for (i = 0; i < count; ++i) { |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 757 | unsigned long *flags; |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 758 | const char *dest; |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 759 | const char *type; |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 760 | const char *src = consumestr(&serialized, &length); |
| 761 | if (!src) |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 762 | goto bad_mounts; |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 763 | dest = consumestr(&serialized, &length); |
| 764 | if (!dest) |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 765 | goto bad_mounts; |
| 766 | type = consumestr(&serialized, &length); |
| 767 | if (!type) |
| 768 | goto bad_mounts; |
| 769 | flags = consumebytes(sizeof(*flags), &serialized, &length); |
| 770 | if (!flags) |
| 771 | goto bad_mounts; |
| 772 | if (minijail_mount(j, src, dest, type, *flags)) |
| 773 | goto bad_mounts; |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 774 | } |
| 775 | |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 776 | return 0; |
Will Drewry | bee7ba7 | 2011-10-21 20:47:01 -0500 | [diff] [blame] | 777 | |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 778 | bad_mounts: |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 779 | if (j->flags.seccomp_filter && j->filter_len > 0) { |
| 780 | free(j->filter_prog->filter); |
| 781 | free(j->filter_prog); |
| 782 | } |
Will Drewry | bee7ba7 | 2011-10-21 20:47:01 -0500 | [diff] [blame] | 783 | bad_filters: |
Andrew Bresticker | eac2894 | 2015-11-11 16:04:46 -0800 | [diff] [blame] | 784 | if (j->alt_syscall_table) |
| 785 | free(j->alt_syscall_table); |
| 786 | bad_syscall_table: |
Will Drewry | bee7ba7 | 2011-10-21 20:47:01 -0500 | [diff] [blame] | 787 | if (j->chrootdir) |
| 788 | free(j->chrootdir); |
| 789 | bad_chrootdir: |
| 790 | if (j->user) |
| 791 | free(j->user); |
| 792 | clear_pointers: |
| 793 | j->user = NULL; |
| 794 | j->chrootdir = NULL; |
Andrew Bresticker | eac2894 | 2015-11-11 16:04:46 -0800 | [diff] [blame] | 795 | j->alt_syscall_table = NULL; |
Will Drewry | bee7ba7 | 2011-10-21 20:47:01 -0500 | [diff] [blame] | 796 | out: |
| 797 | return ret; |
Will Drewry | 2ddaad0 | 2011-09-16 11:36:08 -0500 | [diff] [blame] | 798 | } |
| 799 | |
Yu-Hsi Chiang | 10e9123 | 2015-08-05 14:40:45 +0800 | [diff] [blame] | 800 | static void write_ugid_mappings(const struct minijail *j, int *pipe_fds) |
| 801 | { |
| 802 | int fd, ret, len; |
| 803 | size_t sz; |
| 804 | char fname[32]; |
| 805 | close(pipe_fds[0]); |
| 806 | |
| 807 | sz = sizeof(fname); |
| 808 | if (j->uidmap) { |
| 809 | ret = snprintf(fname, sz, "/proc/%d/uid_map", j->initpid); |
Jorge Lucangeli Obes | 2034274 | 2015-10-27 11:39:59 -0700 | [diff] [blame] | 810 | if (ret < 0 || (size_t)ret >= sz) |
Yu-Hsi Chiang | 10e9123 | 2015-08-05 14:40:45 +0800 | [diff] [blame] | 811 | die("failed to write file name of uid_map"); |
| 812 | fd = open(fname, O_WRONLY); |
| 813 | if (fd < 0) |
| 814 | pdie("failed to open '%s'", fname); |
| 815 | len = strlen(j->uidmap); |
| 816 | if (write(fd, j->uidmap, len) < len) |
| 817 | die("failed to set uid_map"); |
| 818 | close(fd); |
| 819 | } |
| 820 | if (j->gidmap) { |
| 821 | ret = snprintf(fname, sz, "/proc/%d/gid_map", j->initpid); |
Jorge Lucangeli Obes | 2034274 | 2015-10-27 11:39:59 -0700 | [diff] [blame] | 822 | if (ret < 0 || (size_t)ret >= sz) |
Yu-Hsi Chiang | 10e9123 | 2015-08-05 14:40:45 +0800 | [diff] [blame] | 823 | die("failed to write file name of gid_map"); |
| 824 | fd = open(fname, O_WRONLY); |
| 825 | if (fd < 0) |
| 826 | pdie("failed to open '%s'", fname); |
| 827 | len = strlen(j->gidmap); |
| 828 | if (write(fd, j->gidmap, len) < len) |
| 829 | die("failed to set gid_map"); |
| 830 | close(fd); |
| 831 | } |
| 832 | |
| 833 | close(pipe_fds[1]); |
| 834 | } |
| 835 | |
| 836 | static void enter_user_namespace(const struct minijail *j, int *pipe_fds) |
| 837 | { |
| 838 | char buf; |
| 839 | |
| 840 | close(pipe_fds[1]); |
| 841 | |
| 842 | /* Wait for parent to set up uid/gid mappings. */ |
| 843 | if (read(pipe_fds[0], &buf, 1) != 0) |
| 844 | die("failed to sync with parent"); |
| 845 | close(pipe_fds[0]); |
| 846 | |
| 847 | if (j->uidmap && setresuid(0, 0, 0)) |
| 848 | pdie("setresuid"); |
| 849 | if (j->gidmap && setresgid(0, 0, 0)) |
| 850 | pdie("setresgid"); |
| 851 | } |
| 852 | |
Jorge Lucangeli Obes | d0a6e2f | 2015-11-24 14:21:21 -0800 | [diff] [blame] | 853 | /* |
| 854 | * mount_one: Applies mounts from @m for @j, recursing as needed. |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 855 | * @j Minijail these mounts are for |
| 856 | * @m Head of list of mounts |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 857 | * |
| 858 | * Returns 0 for success. |
| 859 | */ |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 860 | static int mount_one(const struct minijail *j, struct mountpoint *m) |
Jorge Lucangeli Obes | c8b21e1 | 2014-06-13 14:26:16 -0700 | [diff] [blame] | 861 | { |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 862 | int ret; |
| 863 | char *dest; |
| 864 | int remount_ro = 0; |
| 865 | |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 866 | /* dest has a leading "/" */ |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 867 | if (asprintf(&dest, "%s%s", j->chrootdir, m->dest) < 0) |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 868 | return -ENOMEM; |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 869 | |
| 870 | /* |
| 871 | * R/O bind mounts have to be remounted since bind and ro can't both be |
| 872 | * specified in the original bind mount. Remount R/O after the initial |
| 873 | * mount. |
| 874 | */ |
| 875 | if ((m->flags & MS_BIND) && (m->flags & MS_RDONLY)) { |
| 876 | remount_ro = 1; |
| 877 | m->flags &= ~MS_RDONLY; |
Elly Jones | a105963 | 2011-12-15 15:17:07 -0500 | [diff] [blame] | 878 | } |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 879 | |
| 880 | ret = mount(m->src, dest, m->type, m->flags, NULL); |
| 881 | if (ret) |
| 882 | pdie("mount: %s -> %s", m->src, dest); |
| 883 | |
| 884 | if (remount_ro) { |
| 885 | m->flags |= MS_RDONLY; |
| 886 | ret = mount(m->src, dest, NULL, |
| 887 | m->flags | MS_REMOUNT, NULL); |
| 888 | if (ret) |
| 889 | pdie("bind ro: %s -> %s", m->src, dest); |
| 890 | } |
| 891 | |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 892 | free(dest); |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 893 | if (m->next) |
| 894 | return mount_one(j, m->next); |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 895 | return ret; |
| 896 | } |
| 897 | |
Jorge Lucangeli Obes | c8b21e1 | 2014-06-13 14:26:16 -0700 | [diff] [blame] | 898 | int enter_chroot(const struct minijail *j) |
| 899 | { |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 900 | int ret; |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 901 | |
| 902 | if (j->mounts_head && (ret = mount_one(j, j->mounts_head))) |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 903 | return ret; |
| 904 | |
| 905 | if (chroot(j->chrootdir)) |
| 906 | return -errno; |
| 907 | |
| 908 | if (chdir("/")) |
| 909 | return -errno; |
| 910 | |
| 911 | return 0; |
| 912 | } |
| 913 | |
Yu-Hsi Chiang | 64d65a7 | 2015-08-13 17:43:27 +0800 | [diff] [blame] | 914 | int enter_pivot_root(const struct minijail *j) |
| 915 | { |
Yu-Hsi Chiang | e0a530e | 2015-09-08 18:49:49 +0800 | [diff] [blame] | 916 | int ret, oldroot, newroot; |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 917 | |
| 918 | if (j->mounts_head && (ret = mount_one(j, j->mounts_head))) |
Yu-Hsi Chiang | 64d65a7 | 2015-08-13 17:43:27 +0800 | [diff] [blame] | 919 | return ret; |
| 920 | |
Jorge Lucangeli Obes | 43a6a86 | 2015-12-04 14:53:36 -0800 | [diff] [blame] | 921 | /* |
| 922 | * Keep the fd for both old and new root. |
| 923 | * It will be used in fchdir later. |
| 924 | */ |
Yu-Hsi Chiang | e0a530e | 2015-09-08 18:49:49 +0800 | [diff] [blame] | 925 | oldroot = open("/", O_DIRECTORY | O_RDONLY); |
| 926 | if (oldroot < 0) |
| 927 | pdie("failed to open / for fchdir"); |
| 928 | newroot = open(j->chrootdir, O_DIRECTORY | O_RDONLY); |
| 929 | if (newroot < 0) |
| 930 | pdie("failed to open %s for fchdir", j->chrootdir); |
| 931 | |
Jorge Lucangeli Obes | 43a6a86 | 2015-12-04 14:53:36 -0800 | [diff] [blame] | 932 | /* |
| 933 | * To ensure chrootdir is the root of a file system, |
| 934 | * do a self bind mount. |
| 935 | */ |
Yu-Hsi Chiang | 64d65a7 | 2015-08-13 17:43:27 +0800 | [diff] [blame] | 936 | if (mount(j->chrootdir, j->chrootdir, "bind", MS_BIND | MS_REC, "")) |
| 937 | pdie("failed to bind mount '%s'", j->chrootdir); |
| 938 | if (chdir(j->chrootdir)) |
| 939 | return -errno; |
Yu-Hsi Chiang | e0a530e | 2015-09-08 18:49:49 +0800 | [diff] [blame] | 940 | if (syscall(SYS_pivot_root, ".", ".")) |
Yu-Hsi Chiang | 64d65a7 | 2015-08-13 17:43:27 +0800 | [diff] [blame] | 941 | pdie("pivot_root"); |
Yu-Hsi Chiang | e0a530e | 2015-09-08 18:49:49 +0800 | [diff] [blame] | 942 | |
| 943 | /* |
| 944 | * Now the old root is mounted on top of the new root. Use fchdir to |
| 945 | * change to the old root and unmount it. |
| 946 | */ |
| 947 | if (fchdir(oldroot)) |
| 948 | pdie("failed to fchdir to old /"); |
Yu-Hsi Chiang | 64d65a7 | 2015-08-13 17:43:27 +0800 | [diff] [blame] | 949 | /* The old root might be busy, so use lazy unmount. */ |
Yu-Hsi Chiang | e0a530e | 2015-09-08 18:49:49 +0800 | [diff] [blame] | 950 | if (umount2(".", MNT_DETACH)) |
| 951 | pdie("umount(/)"); |
| 952 | /* Change back to the new root. */ |
| 953 | if (fchdir(newroot)) |
Yu-Hsi Chiang | 64d65a7 | 2015-08-13 17:43:27 +0800 | [diff] [blame] | 954 | return -errno; |
| 955 | if (chroot("/")) |
| 956 | return -errno; |
Jorge Lucangeli Obes | 46a5509 | 2015-10-12 15:31:59 -0700 | [diff] [blame] | 957 | /* Set correct CWD for getcwd(3). */ |
| 958 | if (chdir("/")) |
| 959 | return -errno; |
Yu-Hsi Chiang | 64d65a7 | 2015-08-13 17:43:27 +0800 | [diff] [blame] | 960 | |
| 961 | return 0; |
| 962 | } |
| 963 | |
Lee Campbell | 11af062 | 2014-05-22 12:36:04 -0700 | [diff] [blame] | 964 | int mount_tmp(void) |
| 965 | { |
Jorge Lucangeli Obes | 3901da6 | 2015-03-03 13:55:11 -0800 | [diff] [blame] | 966 | return mount("none", "/tmp", "tmpfs", 0, "size=64M,mode=777"); |
Lee Campbell | 11af062 | 2014-05-22 12:36:04 -0700 | [diff] [blame] | 967 | } |
| 968 | |
Dylan Reid | 791f577 | 2015-09-14 20:02:42 -0700 | [diff] [blame] | 969 | int remount_proc_readonly(const struct minijail *j) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 970 | { |
| 971 | const char *kProcPath = "/proc"; |
| 972 | const unsigned int kSafeFlags = MS_NODEV | MS_NOEXEC | MS_NOSUID; |
Elly Jones | dd3e851 | 2012-01-23 15:13:38 -0500 | [diff] [blame] | 973 | /* |
| 974 | * Right now, we're holding a reference to our parent's old mount of |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 975 | * /proc in our namespace, which means using MS_REMOUNT here would |
| 976 | * mutate our parent's mount as well, even though we're in a VFS |
| 977 | * namespace (!). Instead, remove their mount from our namespace |
Yu-Hsi Chiang | 10e9123 | 2015-08-05 14:40:45 +0800 | [diff] [blame] | 978 | * and make our own. However, if we are in a new user namespace, /proc |
| 979 | * is not seen as mounted, so don't return error if umount() fails. |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 980 | */ |
Jorge Lucangeli Obes | 805be39 | 2015-10-12 15:55:59 -0700 | [diff] [blame] | 981 | if (umount2(kProcPath, MNT_DETACH) && !j->flags.userns) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 982 | return -errno; |
| 983 | if (mount("", kProcPath, "proc", kSafeFlags | MS_RDONLY, "")) |
| 984 | return -errno; |
| 985 | return 0; |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 986 | } |
| 987 | |
Yu-Hsi Chiang | 3cc05ea | 2015-08-11 11:23:17 +0800 | [diff] [blame] | 988 | static void write_pid_file(const struct minijail *j) |
| 989 | { |
| 990 | FILE *fp = fopen(j->pid_file_path, "w"); |
| 991 | |
| 992 | if (!fp) |
| 993 | pdie("failed to open '%s'", j->pid_file_path); |
| 994 | if (fprintf(fp, "%d\n", (int)j->initpid) < 0) |
| 995 | pdie("fprintf(%s)", j->pid_file_path); |
| 996 | if (fclose(fp)) |
| 997 | pdie("fclose(%s)", j->pid_file_path); |
| 998 | } |
| 999 | |
Jorge Lucangeli Obes | 6201cf5 | 2012-08-23 11:42:27 -0700 | [diff] [blame] | 1000 | void drop_ugid(const struct minijail *j) |
| 1001 | { |
Jorge Lucangeli Obes | d16ac49 | 2015-12-03 14:44:35 -0800 | [diff] [blame] | 1002 | if (j->flags.usergroups && j->flags.suppl_gids) { |
| 1003 | die("tried to inherit *and* set supplementary groups;" |
| 1004 | " can only do one"); |
| 1005 | } |
| 1006 | |
Jorge Lucangeli Obes | 6201cf5 | 2012-08-23 11:42:27 -0700 | [diff] [blame] | 1007 | if (j->flags.usergroups) { |
| 1008 | if (initgroups(j->user, j->usergid)) |
| 1009 | pdie("initgroups"); |
Jorge Lucangeli Obes | d16ac49 | 2015-12-03 14:44:35 -0800 | [diff] [blame] | 1010 | } else if (j->flags.suppl_gids) { |
| 1011 | if (setgroups(j->suppl_gid_count, j->suppl_gid_list)) { |
| 1012 | pdie("setgroups"); |
| 1013 | } |
Jorge Lucangeli Obes | 6201cf5 | 2012-08-23 11:42:27 -0700 | [diff] [blame] | 1014 | } else { |
Jorge Lucangeli Obes | d0a6e2f | 2015-11-24 14:21:21 -0800 | [diff] [blame] | 1015 | /* |
Jorge Lucangeli Obes | d16ac49 | 2015-12-03 14:44:35 -0800 | [diff] [blame] | 1016 | * Only attempt to clear supplementary groups if we are changing |
Jorge Lucangeli Obes | d0a6e2f | 2015-11-24 14:21:21 -0800 | [diff] [blame] | 1017 | * users. |
| 1018 | */ |
Jorge Lucangeli Obes | 6201cf5 | 2012-08-23 11:42:27 -0700 | [diff] [blame] | 1019 | if ((j->uid || j->gid) && setgroups(0, NULL)) |
| 1020 | pdie("setgroups"); |
| 1021 | } |
| 1022 | |
| 1023 | if (j->flags.gid && setresgid(j->gid, j->gid, j->gid)) |
| 1024 | pdie("setresgid"); |
| 1025 | |
| 1026 | if (j->flags.uid && setresuid(j->uid, j->uid, j->uid)) |
| 1027 | pdie("setresuid"); |
| 1028 | } |
| 1029 | |
Mike Frysinger | 3adfef7 | 2013-05-09 17:19:08 -0400 | [diff] [blame] | 1030 | /* |
| 1031 | * We specifically do not use cap_valid() as that only tells us the last |
| 1032 | * valid cap we were *compiled* against (i.e. what the version of kernel |
| 1033 | * headers says). If we run on a different kernel version, then it's not |
| 1034 | * uncommon for that to be less (if an older kernel) or more (if a newer |
| 1035 | * kernel). So suck up the answer via /proc. |
| 1036 | */ |
Jorge Lucangeli Obes | 2034274 | 2015-10-27 11:39:59 -0700 | [diff] [blame] | 1037 | static unsigned int get_last_valid_cap() |
Mike Frysinger | 3adfef7 | 2013-05-09 17:19:08 -0400 | [diff] [blame] | 1038 | { |
Dylan Reid | f682d47 | 2015-09-17 21:39:07 -0700 | [diff] [blame] | 1039 | const char cap_file[] = "/proc/sys/kernel/cap_last_cap"; |
| 1040 | FILE *fp = fopen(cap_file, "re"); |
Jorge Lucangeli Obes | 2034274 | 2015-10-27 11:39:59 -0700 | [diff] [blame] | 1041 | unsigned int last_valid_cap; |
Mike Frysinger | 3adfef7 | 2013-05-09 17:19:08 -0400 | [diff] [blame] | 1042 | |
Dylan Reid | f682d47 | 2015-09-17 21:39:07 -0700 | [diff] [blame] | 1043 | if (fscanf(fp, "%u", &last_valid_cap) != 1) |
| 1044 | pdie("fscanf(%s)", cap_file); |
| 1045 | fclose(fp); |
Mike Frysinger | 3adfef7 | 2013-05-09 17:19:08 -0400 | [diff] [blame] | 1046 | |
Dylan Reid | f682d47 | 2015-09-17 21:39:07 -0700 | [diff] [blame] | 1047 | return last_valid_cap; |
Mike Frysinger | 3adfef7 | 2013-05-09 17:19:08 -0400 | [diff] [blame] | 1048 | } |
| 1049 | |
Jorge Lucangeli Obes | 2034274 | 2015-10-27 11:39:59 -0700 | [diff] [blame] | 1050 | void drop_caps(const struct minijail *j, unsigned int last_valid_cap) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1051 | { |
| 1052 | cap_t caps = cap_get_proc(); |
Kees Cook | 323878a | 2013-02-05 15:35:24 -0800 | [diff] [blame] | 1053 | cap_value_t flag[1]; |
Kees Cook | e5609ac | 2013-02-06 14:12:41 -0800 | [diff] [blame] | 1054 | const uint64_t one = 1; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1055 | unsigned int i; |
| 1056 | if (!caps) |
| 1057 | die("can't get process caps"); |
| 1058 | if (cap_clear_flag(caps, CAP_INHERITABLE)) |
| 1059 | die("can't clear inheritable caps"); |
| 1060 | if (cap_clear_flag(caps, CAP_EFFECTIVE)) |
| 1061 | die("can't clear effective caps"); |
| 1062 | if (cap_clear_flag(caps, CAP_PERMITTED)) |
| 1063 | die("can't clear permitted caps"); |
Dylan Reid | f682d47 | 2015-09-17 21:39:07 -0700 | [diff] [blame] | 1064 | for (i = 0; i < sizeof(j->caps) * 8 && i <= last_valid_cap; ++i) { |
Kees Cook | 323878a | 2013-02-05 15:35:24 -0800 | [diff] [blame] | 1065 | /* Keep CAP_SETPCAP for dropping bounding set bits. */ |
Kees Cook | e5609ac | 2013-02-06 14:12:41 -0800 | [diff] [blame] | 1066 | if (i != CAP_SETPCAP && !(j->caps & (one << i))) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1067 | continue; |
Kees Cook | 323878a | 2013-02-05 15:35:24 -0800 | [diff] [blame] | 1068 | flag[0] = i; |
| 1069 | if (cap_set_flag(caps, CAP_EFFECTIVE, 1, flag, CAP_SET)) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1070 | die("can't add effective cap"); |
Kees Cook | 323878a | 2013-02-05 15:35:24 -0800 | [diff] [blame] | 1071 | if (cap_set_flag(caps, CAP_PERMITTED, 1, flag, CAP_SET)) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1072 | die("can't add permitted cap"); |
Kees Cook | 323878a | 2013-02-05 15:35:24 -0800 | [diff] [blame] | 1073 | if (cap_set_flag(caps, CAP_INHERITABLE, 1, flag, CAP_SET)) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1074 | die("can't add inheritable cap"); |
| 1075 | } |
| 1076 | if (cap_set_proc(caps)) |
Kees Cook | 323878a | 2013-02-05 15:35:24 -0800 | [diff] [blame] | 1077 | die("can't apply initial cleaned capset"); |
| 1078 | |
| 1079 | /* |
| 1080 | * Instead of dropping bounding set first, do it here in case |
| 1081 | * the caller had a more permissive bounding set which could |
| 1082 | * have been used above to raise a capability that wasn't already |
| 1083 | * present. This requires CAP_SETPCAP, so we raised/kept it above. |
| 1084 | */ |
Dylan Reid | f682d47 | 2015-09-17 21:39:07 -0700 | [diff] [blame] | 1085 | for (i = 0; i < sizeof(j->caps) * 8 && i <= last_valid_cap; ++i) { |
Kees Cook | e5609ac | 2013-02-06 14:12:41 -0800 | [diff] [blame] | 1086 | if (j->caps & (one << i)) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1087 | continue; |
| 1088 | if (prctl(PR_CAPBSET_DROP, i)) |
| 1089 | pdie("prctl(PR_CAPBSET_DROP)"); |
| 1090 | } |
Kees Cook | 323878a | 2013-02-05 15:35:24 -0800 | [diff] [blame] | 1091 | |
| 1092 | /* If CAP_SETPCAP wasn't specifically requested, now we remove it. */ |
Kees Cook | e5609ac | 2013-02-06 14:12:41 -0800 | [diff] [blame] | 1093 | if ((j->caps & (one << CAP_SETPCAP)) == 0) { |
Kees Cook | 323878a | 2013-02-05 15:35:24 -0800 | [diff] [blame] | 1094 | flag[0] = CAP_SETPCAP; |
| 1095 | if (cap_set_flag(caps, CAP_EFFECTIVE, 1, flag, CAP_CLEAR)) |
| 1096 | die("can't clear effective cap"); |
| 1097 | if (cap_set_flag(caps, CAP_PERMITTED, 1, flag, CAP_CLEAR)) |
| 1098 | die("can't clear permitted cap"); |
| 1099 | if (cap_set_flag(caps, CAP_INHERITABLE, 1, flag, CAP_CLEAR)) |
| 1100 | die("can't clear inheritable cap"); |
| 1101 | } |
| 1102 | |
| 1103 | if (cap_set_proc(caps)) |
| 1104 | die("can't apply final cleaned capset"); |
| 1105 | |
| 1106 | cap_free(caps); |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1107 | } |
| 1108 | |
Jorge Lucangeli Obes | 6201cf5 | 2012-08-23 11:42:27 -0700 | [diff] [blame] | 1109 | void set_seccomp_filter(const struct minijail *j) |
| 1110 | { |
| 1111 | /* |
| 1112 | * Set no_new_privs. See </kernel/seccomp.c> and </kernel/sys.c> |
| 1113 | * in the kernel source tree for an explanation of the parameters. |
| 1114 | */ |
| 1115 | if (j->flags.no_new_privs) { |
| 1116 | if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) |
| 1117 | pdie("prctl(PR_SET_NO_NEW_PRIVS)"); |
| 1118 | } |
| 1119 | |
| 1120 | /* |
| 1121 | * If we're logging seccomp filter failures, |
| 1122 | * install the SIGSYS handler first. |
| 1123 | */ |
| 1124 | if (j->flags.seccomp_filter && j->flags.log_seccomp_filter) { |
| 1125 | if (install_sigsys_handler()) |
| 1126 | pdie("install SIGSYS handler"); |
| 1127 | warn("logging seccomp filter failures"); |
| 1128 | } |
| 1129 | |
| 1130 | /* |
| 1131 | * Install the syscall filter. |
| 1132 | */ |
| 1133 | if (j->flags.seccomp_filter) { |
Jorge Lucangeli Obes | 43a6a86 | 2015-12-04 14:53:36 -0800 | [diff] [blame] | 1134 | if (prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, |
| 1135 | j->filter_prog)) { |
Utkarsh Sanghi | 0ef8a66 | 2014-08-18 15:50:11 -0700 | [diff] [blame] | 1136 | if ((errno == ENOSYS) && SECCOMP_SOFTFAIL) { |
| 1137 | warn("seccomp not supported"); |
| 1138 | return; |
| 1139 | } |
Jorge Lucangeli Obes | 6201cf5 | 2012-08-23 11:42:27 -0700 | [diff] [blame] | 1140 | pdie("prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER)"); |
Utkarsh Sanghi | 0ef8a66 | 2014-08-18 15:50:11 -0700 | [diff] [blame] | 1141 | } |
Jorge Lucangeli Obes | 6201cf5 | 2012-08-23 11:42:27 -0700 | [diff] [blame] | 1142 | } |
| 1143 | } |
| 1144 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 1145 | void API minijail_enter(const struct minijail *j) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1146 | { |
Dylan Reid | f682d47 | 2015-09-17 21:39:07 -0700 | [diff] [blame] | 1147 | /* |
| 1148 | * Get the last valid cap from /proc, since /proc can be unmounted |
| 1149 | * before drop_caps(). |
| 1150 | */ |
Jorge Lucangeli Obes | 2034274 | 2015-10-27 11:39:59 -0700 | [diff] [blame] | 1151 | unsigned int last_valid_cap = get_last_valid_cap(); |
Dylan Reid | f682d47 | 2015-09-17 21:39:07 -0700 | [diff] [blame] | 1152 | |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1153 | if (j->flags.pids) |
| 1154 | die("tried to enter a pid-namespaced jail;" |
Jorge Lucangeli Obes | 1563b5b | 2014-07-10 07:01:53 -0700 | [diff] [blame] | 1155 | " try minijail_run()?"); |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1156 | |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1157 | if (j->flags.usergroups && !j->user) |
| 1158 | die("usergroup inheritance without username"); |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1159 | |
Elly Jones | dd3e851 | 2012-01-23 15:13:38 -0500 | [diff] [blame] | 1160 | /* |
| 1161 | * We can't recover from failures if we've dropped privileges partially, |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1162 | * so we don't even try. If any of our operations fail, we abort() the |
| 1163 | * entire process. |
| 1164 | */ |
Jorge Lucangeli Obes | 1563b5b | 2014-07-10 07:01:53 -0700 | [diff] [blame] | 1165 | if (j->flags.enter_vfs && setns(j->mountns_fd, CLONE_NEWNS)) |
| 1166 | pdie("setns(CLONE_NEWNS)"); |
| 1167 | |
Jorge Lucangeli Obes | 805be39 | 2015-10-12 15:55:59 -0700 | [diff] [blame] | 1168 | if (j->flags.vfs) { |
Jorge Lucangeli Obes | f7a3868 | 2015-12-04 15:43:30 -0800 | [diff] [blame] | 1169 | if (unshare(CLONE_NEWNS)) |
| 1170 | pdie("unshare(vfs)"); |
| 1171 | /* |
| 1172 | * Remount all filesystems as private. If they are shared |
| 1173 | * new bind mounts will creep out of our namespace. |
| 1174 | * https://www.kernel.org/doc/Documentation/filesystems/sharedsubtree.txt |
| 1175 | */ |
| 1176 | if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL)) |
| 1177 | pdie("mount(/, private)"); |
| 1178 | } |
Elly Fong-Jones | 6c08630 | 2013-03-20 17:15:28 -0400 | [diff] [blame] | 1179 | |
Dylan Reid | f794247 | 2015-11-18 17:55:26 -0800 | [diff] [blame] | 1180 | if (j->flags.ipc && unshare(CLONE_NEWIPC)) { |
| 1181 | pdie("unshare(ipc)"); |
| 1182 | } |
| 1183 | |
Dylan Reid | 1102f5a | 2015-09-15 11:52:20 -0700 | [diff] [blame] | 1184 | if (j->flags.enter_net) { |
| 1185 | if (setns(j->netns_fd, CLONE_NEWNET)) |
| 1186 | pdie("setns(CLONE_NEWNET)"); |
| 1187 | } else if (j->flags.net && unshare(CLONE_NEWNET)) { |
Elly Fong-Jones | 6c08630 | 2013-03-20 17:15:28 -0400 | [diff] [blame] | 1188 | pdie("unshare(net)"); |
Dylan Reid | 1102f5a | 2015-09-15 11:52:20 -0700 | [diff] [blame] | 1189 | } |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1190 | |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 1191 | if (j->flags.chroot && enter_chroot(j)) |
| 1192 | pdie("chroot"); |
| 1193 | |
Yu-Hsi Chiang | 64d65a7 | 2015-08-13 17:43:27 +0800 | [diff] [blame] | 1194 | if (j->flags.pivot_root && enter_pivot_root(j)) |
| 1195 | pdie("pivot_root"); |
| 1196 | |
Jorge Lucangeli Obes | 3901da6 | 2015-03-03 13:55:11 -0800 | [diff] [blame] | 1197 | if (j->flags.mount_tmp && mount_tmp()) |
Lee Campbell | 11af062 | 2014-05-22 12:36:04 -0700 | [diff] [blame] | 1198 | pdie("mount_tmp"); |
| 1199 | |
Dylan Reid | 791f577 | 2015-09-14 20:02:42 -0700 | [diff] [blame] | 1200 | if (j->flags.remount_proc_ro && remount_proc_readonly(j)) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1201 | pdie("remount"); |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1202 | |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1203 | if (j->flags.caps) { |
Elly Jones | dd3e851 | 2012-01-23 15:13:38 -0500 | [diff] [blame] | 1204 | /* |
| 1205 | * POSIX capabilities are a bit tricky. If we drop our |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1206 | * capability to change uids, our attempt to use setuid() |
| 1207 | * below will fail. Hang on to root caps across setuid(), then |
| 1208 | * lock securebits. |
| 1209 | */ |
| 1210 | if (prctl(PR_SET_KEEPCAPS, 1)) |
| 1211 | pdie("prctl(PR_SET_KEEPCAPS)"); |
| 1212 | if (prctl |
| 1213 | (PR_SET_SECUREBITS, SECURE_ALL_BITS | SECURE_ALL_LOCKS)) |
| 1214 | pdie("prctl(PR_SET_SECUREBITS)"); |
| 1215 | } |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1216 | |
Jorge Lucangeli Obes | c2c9bcc | 2012-05-01 09:30:24 -0700 | [diff] [blame] | 1217 | /* |
Jorge Lucangeli Obes | 6201cf5 | 2012-08-23 11:42:27 -0700 | [diff] [blame] | 1218 | * If we're setting no_new_privs, we can drop privileges |
| 1219 | * before setting seccomp filter. This way filter policies |
| 1220 | * don't need to allow privilege-dropping syscalls. |
Jorge Lucangeli Obes | c2c9bcc | 2012-05-01 09:30:24 -0700 | [diff] [blame] | 1221 | */ |
| 1222 | if (j->flags.no_new_privs) { |
Jorge Lucangeli Obes | 6201cf5 | 2012-08-23 11:42:27 -0700 | [diff] [blame] | 1223 | drop_ugid(j); |
| 1224 | if (j->flags.caps) |
Dylan Reid | f682d47 | 2015-09-17 21:39:07 -0700 | [diff] [blame] | 1225 | drop_caps(j, last_valid_cap); |
Jorge Lucangeli Obes | c2c9bcc | 2012-05-01 09:30:24 -0700 | [diff] [blame] | 1226 | |
Jorge Lucangeli Obes | 6201cf5 | 2012-08-23 11:42:27 -0700 | [diff] [blame] | 1227 | set_seccomp_filter(j); |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1228 | } else { |
Jorge Lucangeli Obes | 6201cf5 | 2012-08-23 11:42:27 -0700 | [diff] [blame] | 1229 | /* |
| 1230 | * If we're not setting no_new_privs, |
| 1231 | * we need to set seccomp filter *before* dropping privileges. |
| 1232 | * WARNING: this means that filter policies *must* allow |
| 1233 | * setgroups()/setresgid()/setresuid() for dropping root and |
| 1234 | * capget()/capset()/prctl() for dropping caps. |
| 1235 | */ |
| 1236 | set_seccomp_filter(j); |
| 1237 | |
| 1238 | drop_ugid(j); |
| 1239 | if (j->flags.caps) |
Dylan Reid | f682d47 | 2015-09-17 21:39:07 -0700 | [diff] [blame] | 1240 | drop_caps(j, last_valid_cap); |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1241 | } |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1242 | |
Elly Jones | dd3e851 | 2012-01-23 15:13:38 -0500 | [diff] [blame] | 1243 | /* |
Andrew Bresticker | eac2894 | 2015-11-11 16:04:46 -0800 | [diff] [blame] | 1244 | * Select the specified alternate syscall table. The table must not |
| 1245 | * block prctl(2) if we're using seccomp as well. |
| 1246 | */ |
| 1247 | if (j->flags.alt_syscall) { |
| 1248 | if (prctl(PR_ALT_SYSCALL, 1, j->alt_syscall_table)) |
| 1249 | pdie("prctl(PR_ALT_SYSCALL)"); |
| 1250 | } |
| 1251 | |
| 1252 | /* |
Elly Jones | dd3e851 | 2012-01-23 15:13:38 -0500 | [diff] [blame] | 1253 | * seccomp has to come last since it cuts off all the other |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1254 | * privilege-dropping syscalls :) |
| 1255 | */ |
Utkarsh Sanghi | 0ef8a66 | 2014-08-18 15:50:11 -0700 | [diff] [blame] | 1256 | if (j->flags.seccomp && prctl(PR_SET_SECCOMP, 1)) { |
| 1257 | if ((errno == ENOSYS) && SECCOMP_SOFTFAIL) { |
| 1258 | warn("seccomp not supported"); |
| 1259 | return; |
| 1260 | } |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1261 | pdie("prctl(PR_SET_SECCOMP)"); |
Utkarsh Sanghi | 0ef8a66 | 2014-08-18 15:50:11 -0700 | [diff] [blame] | 1262 | } |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1263 | } |
| 1264 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 1265 | /* TODO(wad) will visibility affect this variable? */ |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1266 | static int init_exitstatus = 0; |
| 1267 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 1268 | void init_term(int __attribute__ ((unused)) sig) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1269 | { |
| 1270 | _exit(init_exitstatus); |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1271 | } |
| 1272 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 1273 | int init(pid_t rootpid) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1274 | { |
| 1275 | pid_t pid; |
| 1276 | int status; |
| 1277 | /* so that we exit with the right status */ |
| 1278 | signal(SIGTERM, init_term); |
| 1279 | /* TODO(wad) self jail with seccomp_filters here. */ |
| 1280 | while ((pid = wait(&status)) > 0) { |
Elly Jones | dd3e851 | 2012-01-23 15:13:38 -0500 | [diff] [blame] | 1281 | /* |
| 1282 | * This loop will only end when either there are no processes |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1283 | * left inside our pid namespace or we get a signal. |
| 1284 | */ |
| 1285 | if (pid == rootpid) |
| 1286 | init_exitstatus = status; |
| 1287 | } |
| 1288 | if (!WIFEXITED(init_exitstatus)) |
| 1289 | _exit(MINIJAIL_ERR_INIT); |
| 1290 | _exit(WEXITSTATUS(init_exitstatus)); |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1291 | } |
| 1292 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 1293 | int API minijail_from_fd(int fd, struct minijail *j) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1294 | { |
| 1295 | size_t sz = 0; |
| 1296 | size_t bytes = read(fd, &sz, sizeof(sz)); |
| 1297 | char *buf; |
| 1298 | int r; |
| 1299 | if (sizeof(sz) != bytes) |
| 1300 | return -EINVAL; |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1301 | if (sz > USHRT_MAX) /* arbitrary sanity check */ |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1302 | return -E2BIG; |
| 1303 | buf = malloc(sz); |
| 1304 | if (!buf) |
| 1305 | return -ENOMEM; |
| 1306 | bytes = read(fd, buf, sz); |
| 1307 | if (bytes != sz) { |
| 1308 | free(buf); |
| 1309 | return -EINVAL; |
| 1310 | } |
| 1311 | r = minijail_unmarshal(j, buf, sz); |
| 1312 | free(buf); |
| 1313 | return r; |
Will Drewry | 2f54b6a | 2011-09-16 13:45:31 -0500 | [diff] [blame] | 1314 | } |
| 1315 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 1316 | int API minijail_to_fd(struct minijail *j, int fd) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1317 | { |
| 1318 | char *buf; |
| 1319 | size_t sz = minijail_size(j); |
| 1320 | ssize_t written; |
| 1321 | int r; |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1322 | |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1323 | if (!sz) |
| 1324 | return -EINVAL; |
| 1325 | buf = malloc(sz); |
| 1326 | r = minijail_marshal(j, buf, sz); |
| 1327 | if (r) { |
| 1328 | free(buf); |
| 1329 | return r; |
| 1330 | } |
| 1331 | /* Sends [size][minijail]. */ |
| 1332 | written = write(fd, &sz, sizeof(sz)); |
| 1333 | if (written != sizeof(sz)) { |
| 1334 | free(buf); |
| 1335 | return -EFAULT; |
| 1336 | } |
| 1337 | written = write(fd, buf, sz); |
| 1338 | if (written < 0 || (size_t) written != sz) { |
| 1339 | free(buf); |
| 1340 | return -EFAULT; |
| 1341 | } |
| 1342 | free(buf); |
| 1343 | return 0; |
Will Drewry | 2f54b6a | 2011-09-16 13:45:31 -0500 | [diff] [blame] | 1344 | } |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1345 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 1346 | int setup_preload(void) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1347 | { |
Daniel Erat | 5b7a318 | 2015-08-19 16:06:22 -0600 | [diff] [blame] | 1348 | #if defined(__ANDROID__) |
Jorge Lucangeli Obes | a21c8fc | 2015-07-15 16:22:34 -0700 | [diff] [blame] | 1349 | /* Don't use LDPRELOAD on Brillo. */ |
| 1350 | return 0; |
| 1351 | #else |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1352 | char *oldenv = getenv(kLdPreloadEnvVar) ? : ""; |
| 1353 | char *newenv = malloc(strlen(oldenv) + 2 + strlen(PRELOADPATH)); |
| 1354 | if (!newenv) |
| 1355 | return -ENOMEM; |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1356 | |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1357 | /* Only insert a separating space if we have something to separate... */ |
| 1358 | sprintf(newenv, "%s%s%s", oldenv, strlen(oldenv) ? " " : "", |
| 1359 | PRELOADPATH); |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1360 | |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1361 | /* setenv() makes a copy of the string we give it. */ |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1362 | setenv(kLdPreloadEnvVar, newenv, 1); |
| 1363 | free(newenv); |
| 1364 | return 0; |
Jorge Lucangeli Obes | a21c8fc | 2015-07-15 16:22:34 -0700 | [diff] [blame] | 1365 | #endif |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1366 | } |
| 1367 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 1368 | int setup_pipe(int fds[2]) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1369 | { |
| 1370 | int r = pipe(fds); |
| 1371 | char fd_buf[11]; |
| 1372 | if (r) |
| 1373 | return r; |
| 1374 | r = snprintf(fd_buf, sizeof(fd_buf), "%d", fds[0]); |
| 1375 | if (r <= 0) |
| 1376 | return -EINVAL; |
| 1377 | setenv(kFdEnvVar, fd_buf, 1); |
| 1378 | return 0; |
Will Drewry | f89aef5 | 2011-09-16 16:48:57 -0500 | [diff] [blame] | 1379 | } |
| 1380 | |
Jorge Lucangeli Obes | 339a113 | 2013-02-15 16:53:47 -0800 | [diff] [blame] | 1381 | int setup_pipe_end(int fds[2], size_t index) |
| 1382 | { |
| 1383 | if (index > 1) |
| 1384 | return -1; |
| 1385 | |
| 1386 | close(fds[1 - index]); |
| 1387 | return fds[index]; |
| 1388 | } |
| 1389 | |
| 1390 | int setup_and_dupe_pipe_end(int fds[2], size_t index, int fd) |
| 1391 | { |
| 1392 | if (index > 1) |
| 1393 | return -1; |
| 1394 | |
| 1395 | close(fds[1 - index]); |
| 1396 | /* dup2(2) the corresponding end of the pipe into |fd|. */ |
| 1397 | return dup2(fds[index], fd); |
| 1398 | } |
| 1399 | |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1400 | int minijail_run_internal(struct minijail *j, const char *filename, |
| 1401 | char *const argv[], pid_t *pchild_pid, |
| 1402 | int *pstdin_fd, int *pstdout_fd, int *pstderr_fd, |
| 1403 | int use_preload); |
| 1404 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 1405 | int API minijail_run(struct minijail *j, const char *filename, |
| 1406 | char *const argv[]) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1407 | { |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1408 | return minijail_run_internal(j, filename, argv, NULL, NULL, NULL, NULL, |
| 1409 | true); |
Jorge Lucangeli Obes | 9807d03 | 2012-04-17 13:36:00 -0700 | [diff] [blame] | 1410 | } |
| 1411 | |
| 1412 | int API minijail_run_pid(struct minijail *j, const char *filename, |
| 1413 | char *const argv[], pid_t *pchild_pid) |
| 1414 | { |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1415 | return minijail_run_internal(j, filename, argv, pchild_pid, |
| 1416 | NULL, NULL, NULL, true); |
Jorge Lucangeli Obes | df4bd35 | 2012-08-29 19:12:28 -0700 | [diff] [blame] | 1417 | } |
| 1418 | |
| 1419 | int API minijail_run_pipe(struct minijail *j, const char *filename, |
Jorge Lucangeli Obes | 6537a56 | 2012-09-05 10:39:40 -0700 | [diff] [blame] | 1420 | char *const argv[], int *pstdin_fd) |
Jorge Lucangeli Obes | df4bd35 | 2012-08-29 19:12:28 -0700 | [diff] [blame] | 1421 | { |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1422 | return minijail_run_internal(j, filename, argv, NULL, pstdin_fd, |
| 1423 | NULL, NULL, true); |
Jorge Lucangeli Obes | df4bd35 | 2012-08-29 19:12:28 -0700 | [diff] [blame] | 1424 | } |
| 1425 | |
Jorge Lucangeli Obes | 339a113 | 2013-02-15 16:53:47 -0800 | [diff] [blame] | 1426 | int API minijail_run_pid_pipes(struct minijail *j, const char *filename, |
Jorge Lucangeli Obes | 4ae30cc | 2014-04-10 15:35:33 -0700 | [diff] [blame] | 1427 | char *const argv[], pid_t *pchild_pid, |
| 1428 | int *pstdin_fd, int *pstdout_fd, int *pstderr_fd) |
Jorge Lucangeli Obes | 339a113 | 2013-02-15 16:53:47 -0800 | [diff] [blame] | 1429 | { |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1430 | return minijail_run_internal(j, filename, argv, pchild_pid, |
| 1431 | pstdin_fd, pstdout_fd, pstderr_fd, true); |
| 1432 | } |
| 1433 | |
| 1434 | int API minijail_run_no_preload(struct minijail *j, const char *filename, |
| 1435 | char *const argv[]) |
| 1436 | { |
| 1437 | return minijail_run_internal(j, filename, argv, NULL, NULL, NULL, NULL, |
| 1438 | false); |
| 1439 | } |
| 1440 | |
Samuel Tan | 63187f4 | 2015-10-16 13:01:53 -0700 | [diff] [blame] | 1441 | int API minijail_run_pid_pipes_no_preload(struct minijail *j, |
Jorge Lucangeli Obes | 43a6a86 | 2015-12-04 14:53:36 -0800 | [diff] [blame] | 1442 | const char *filename, |
| 1443 | char *const argv[], |
Samuel Tan | 63187f4 | 2015-10-16 13:01:53 -0700 | [diff] [blame] | 1444 | pid_t *pchild_pid, |
Jorge Lucangeli Obes | 43a6a86 | 2015-12-04 14:53:36 -0800 | [diff] [blame] | 1445 | int *pstdin_fd, int *pstdout_fd, |
| 1446 | int *pstderr_fd) { |
Samuel Tan | 63187f4 | 2015-10-16 13:01:53 -0700 | [diff] [blame] | 1447 | return minijail_run_internal(j, filename, argv, pchild_pid, |
| 1448 | pstdin_fd, pstdout_fd, pstderr_fd, false); |
| 1449 | } |
| 1450 | |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1451 | int minijail_run_internal(struct minijail *j, const char *filename, |
| 1452 | char *const argv[], pid_t *pchild_pid, |
| 1453 | int *pstdin_fd, int *pstdout_fd, int *pstderr_fd, |
| 1454 | int use_preload) |
| 1455 | { |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1456 | char *oldenv, *oldenv_copy = NULL; |
| 1457 | pid_t child_pid; |
| 1458 | int pipe_fds[2]; |
Jorge Lucangeli Obes | df4bd35 | 2012-08-29 19:12:28 -0700 | [diff] [blame] | 1459 | int stdin_fds[2]; |
Jorge Lucangeli Obes | 339a113 | 2013-02-15 16:53:47 -0800 | [diff] [blame] | 1460 | int stdout_fds[2]; |
| 1461 | int stderr_fds[2]; |
Yu-Hsi Chiang | 10e9123 | 2015-08-05 14:40:45 +0800 | [diff] [blame] | 1462 | int userns_pipe_fds[2]; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1463 | int ret; |
Elly Jones | a05d7bb | 2012-06-14 14:09:27 -0400 | [diff] [blame] | 1464 | /* We need to remember this across the minijail_preexec() call. */ |
| 1465 | int pid_namespace = j->flags.pids; |
Yu-Hsi Chiang | 3e954ec | 2015-07-28 16:48:14 +0800 | [diff] [blame] | 1466 | int do_init = j->flags.do_init; |
Ben Chan | 541c7e5 | 2011-08-26 14:55:53 -0700 | [diff] [blame] | 1467 | |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1468 | if (use_preload) { |
| 1469 | oldenv = getenv(kLdPreloadEnvVar); |
| 1470 | if (oldenv) { |
| 1471 | oldenv_copy = strdup(oldenv); |
| 1472 | if (!oldenv_copy) |
| 1473 | return -ENOMEM; |
| 1474 | } |
| 1475 | |
| 1476 | if (setup_preload()) |
| 1477 | return -EFAULT; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1478 | } |
Will Drewry | f89aef5 | 2011-09-16 16:48:57 -0500 | [diff] [blame] | 1479 | |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1480 | if (!use_preload) { |
| 1481 | if (j->flags.caps) |
| 1482 | die("Capabilities are not supported without " |
| 1483 | "LD_PRELOAD"); |
| 1484 | } |
Will Drewry | 2f54b6a | 2011-09-16 13:45:31 -0500 | [diff] [blame] | 1485 | |
Elly Jones | dd3e851 | 2012-01-23 15:13:38 -0500 | [diff] [blame] | 1486 | /* |
Jorge Lucangeli Obes | 3c84df1 | 2015-05-14 17:37:58 -0700 | [diff] [blame] | 1487 | * Make the process group ID of this process equal to its PID, so that |
| 1488 | * both the Minijail process and the jailed process can be killed |
| 1489 | * together. |
| 1490 | * Don't fail on EPERM, since setpgid(0, 0) can only EPERM when |
| 1491 | * the process is already a process group leader. |
| 1492 | */ |
| 1493 | if (setpgid(0 /* use calling PID */, 0 /* make PGID = PID */)) { |
| 1494 | if (errno != EPERM) { |
| 1495 | pdie("setpgid(0, 0)"); |
| 1496 | } |
| 1497 | } |
| 1498 | |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1499 | if (use_preload) { |
| 1500 | /* |
| 1501 | * Before we fork(2) and execve(2) the child process, we need |
| 1502 | * to open a pipe(2) to send the minijail configuration over. |
| 1503 | */ |
| 1504 | if (setup_pipe(pipe_fds)) |
| 1505 | return -EFAULT; |
| 1506 | } |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1507 | |
Jorge Lucangeli Obes | df4bd35 | 2012-08-29 19:12:28 -0700 | [diff] [blame] | 1508 | /* |
| 1509 | * If we want to write to the child process' standard input, |
| 1510 | * create the pipe(2) now. |
| 1511 | */ |
| 1512 | if (pstdin_fd) { |
| 1513 | if (pipe(stdin_fds)) |
| 1514 | return -EFAULT; |
| 1515 | } |
| 1516 | |
Jorge Lucangeli Obes | 339a113 | 2013-02-15 16:53:47 -0800 | [diff] [blame] | 1517 | /* |
| 1518 | * If we want to read from the child process' standard output, |
| 1519 | * create the pipe(2) now. |
| 1520 | */ |
| 1521 | if (pstdout_fd) { |
| 1522 | if (pipe(stdout_fds)) |
| 1523 | return -EFAULT; |
| 1524 | } |
| 1525 | |
| 1526 | /* |
| 1527 | * If we want to read from the child process' standard error, |
| 1528 | * create the pipe(2) now. |
| 1529 | */ |
| 1530 | if (pstderr_fd) { |
| 1531 | if (pipe(stderr_fds)) |
| 1532 | return -EFAULT; |
| 1533 | } |
| 1534 | |
Yu-Hsi Chiang | 10e9123 | 2015-08-05 14:40:45 +0800 | [diff] [blame] | 1535 | /* |
| 1536 | * If we want to set up a new uid/gid mapping in the user namespace, |
| 1537 | * create the pipe(2) to sync between parent and child. |
| 1538 | */ |
| 1539 | if (j->flags.userns) { |
| 1540 | if (pipe(userns_pipe_fds)) |
| 1541 | return -EFAULT; |
| 1542 | } |
| 1543 | |
Jorge Lucangeli Obes | d0a6e2f | 2015-11-24 14:21:21 -0800 | [diff] [blame] | 1544 | /* |
| 1545 | * Use sys_clone() if and only if we're creating a pid namespace. |
Elly Jones | 761b741 | 2012-06-13 15:49:52 -0400 | [diff] [blame] | 1546 | * |
| 1547 | * tl;dr: WARNING: do not mix pid namespaces and multithreading. |
| 1548 | * |
| 1549 | * In multithreaded programs, there are a bunch of locks inside libc, |
| 1550 | * some of which may be held by other threads at the time that we call |
| 1551 | * minijail_run_pid(). If we call fork(), glibc does its level best to |
| 1552 | * ensure that we hold all of these locks before it calls clone() |
| 1553 | * internally and drop them after clone() returns, but when we call |
| 1554 | * sys_clone(2) directly, all that gets bypassed and we end up with a |
| 1555 | * child address space where some of libc's important locks are held by |
| 1556 | * other threads (which did not get cloned, and hence will never release |
| 1557 | * those locks). This is okay so long as we call exec() immediately |
| 1558 | * after, but a bunch of seemingly-innocent libc functions like setenv() |
| 1559 | * take locks. |
| 1560 | * |
| 1561 | * Hence, only call sys_clone() if we need to, in order to get at pid |
| 1562 | * namespacing. If we follow this path, the child's address space might |
| 1563 | * have broken locks; you may only call functions that do not acquire |
| 1564 | * any locks. |
| 1565 | * |
| 1566 | * Unfortunately, fork() acquires every lock it can get its hands on, as |
| 1567 | * previously detailed, so this function is highly likely to deadlock |
| 1568 | * later on (see "deadlock here") if we're multithreaded. |
| 1569 | * |
| 1570 | * We might hack around this by having the clone()d child (init of the |
| 1571 | * pid namespace) return directly, rather than leaving the clone()d |
| 1572 | * process hanging around to be init for the new namespace (and having |
| 1573 | * its fork()ed child return in turn), but that process would be crippled |
| 1574 | * with its libc locks potentially broken. We might try fork()ing in the |
| 1575 | * parent before we clone() to ensure that we own all the locks, but |
| 1576 | * then we have to have the forked child hanging around consuming |
| 1577 | * resources (and possibly having file descriptors / shared memory |
| 1578 | * regions / etc attached). We'd need to keep the child around to avoid |
| 1579 | * having its children get reparented to init. |
| 1580 | * |
| 1581 | * TODO(ellyjones): figure out if the "forked child hanging around" |
| 1582 | * problem is fixable or not. It would be nice if we worked in this |
| 1583 | * case. |
| 1584 | */ |
Yu-Hsi Chiang | 10e9123 | 2015-08-05 14:40:45 +0800 | [diff] [blame] | 1585 | if (pid_namespace) { |
| 1586 | int clone_flags = CLONE_NEWPID | SIGCHLD; |
| 1587 | if (j->flags.userns) |
| 1588 | clone_flags |= CLONE_NEWUSER; |
| 1589 | child_pid = syscall(SYS_clone, clone_flags, NULL); |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1590 | } else { |
Elly Jones | 761b741 | 2012-06-13 15:49:52 -0400 | [diff] [blame] | 1591 | child_pid = fork(); |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1592 | } |
Elly Jones | 761b741 | 2012-06-13 15:49:52 -0400 | [diff] [blame] | 1593 | |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1594 | if (child_pid < 0) { |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1595 | if (use_preload) { |
| 1596 | free(oldenv_copy); |
| 1597 | } |
Lee Campbell | 1e4fc6a | 2014-06-06 17:40:02 -0700 | [diff] [blame] | 1598 | die("failed to fork child"); |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1599 | } |
Will Drewry | f89aef5 | 2011-09-16 16:48:57 -0500 | [diff] [blame] | 1600 | |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1601 | if (child_pid) { |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1602 | if (use_preload) { |
| 1603 | /* Restore parent's LD_PRELOAD. */ |
| 1604 | if (oldenv_copy) { |
| 1605 | setenv(kLdPreloadEnvVar, oldenv_copy, 1); |
| 1606 | free(oldenv_copy); |
| 1607 | } else { |
| 1608 | unsetenv(kLdPreloadEnvVar); |
| 1609 | } |
| 1610 | unsetenv(kFdEnvVar); |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1611 | } |
Jorge Lucangeli Obes | df4bd35 | 2012-08-29 19:12:28 -0700 | [diff] [blame] | 1612 | |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1613 | j->initpid = child_pid; |
Jorge Lucangeli Obes | df4bd35 | 2012-08-29 19:12:28 -0700 | [diff] [blame] | 1614 | |
Yu-Hsi Chiang | 3cc05ea | 2015-08-11 11:23:17 +0800 | [diff] [blame] | 1615 | if (j->flags.pid_file) |
| 1616 | write_pid_file(j); |
| 1617 | |
Yu-Hsi Chiang | 10e9123 | 2015-08-05 14:40:45 +0800 | [diff] [blame] | 1618 | if (j->flags.userns) |
| 1619 | write_ugid_mappings(j, userns_pipe_fds); |
| 1620 | |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1621 | if (use_preload) { |
| 1622 | /* Send marshalled minijail. */ |
| 1623 | close(pipe_fds[0]); /* read endpoint */ |
| 1624 | ret = minijail_to_fd(j, pipe_fds[1]); |
| 1625 | close(pipe_fds[1]); /* write endpoint */ |
| 1626 | if (ret) { |
| 1627 | kill(j->initpid, SIGKILL); |
| 1628 | die("failed to send marshalled minijail"); |
| 1629 | } |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1630 | } |
Jorge Lucangeli Obes | df4bd35 | 2012-08-29 19:12:28 -0700 | [diff] [blame] | 1631 | |
Jorge Lucangeli Obes | 9807d03 | 2012-04-17 13:36:00 -0700 | [diff] [blame] | 1632 | if (pchild_pid) |
| 1633 | *pchild_pid = child_pid; |
Jorge Lucangeli Obes | df4bd35 | 2012-08-29 19:12:28 -0700 | [diff] [blame] | 1634 | |
| 1635 | /* |
| 1636 | * If we want to write to the child process' standard input, |
| 1637 | * set up the write end of the pipe. |
| 1638 | */ |
Jorge Lucangeli Obes | 339a113 | 2013-02-15 16:53:47 -0800 | [diff] [blame] | 1639 | if (pstdin_fd) |
| 1640 | *pstdin_fd = setup_pipe_end(stdin_fds, |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1641 | 1 /* write end */); |
Jorge Lucangeli Obes | 339a113 | 2013-02-15 16:53:47 -0800 | [diff] [blame] | 1642 | |
| 1643 | /* |
| 1644 | * If we want to read from the child process' standard output, |
| 1645 | * set up the read end of the pipe. |
| 1646 | */ |
| 1647 | if (pstdout_fd) |
| 1648 | *pstdout_fd = setup_pipe_end(stdout_fds, |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1649 | 0 /* read end */); |
Jorge Lucangeli Obes | 339a113 | 2013-02-15 16:53:47 -0800 | [diff] [blame] | 1650 | |
| 1651 | /* |
| 1652 | * If we want to read from the child process' standard error, |
| 1653 | * set up the read end of the pipe. |
| 1654 | */ |
| 1655 | if (pstderr_fd) |
| 1656 | *pstderr_fd = setup_pipe_end(stderr_fds, |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1657 | 0 /* read end */); |
Jorge Lucangeli Obes | df4bd35 | 2012-08-29 19:12:28 -0700 | [diff] [blame] | 1658 | |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1659 | return 0; |
| 1660 | } |
| 1661 | free(oldenv_copy); |
Ben Chan | 541c7e5 | 2011-08-26 14:55:53 -0700 | [diff] [blame] | 1662 | |
Yu-Hsi Chiang | 10e9123 | 2015-08-05 14:40:45 +0800 | [diff] [blame] | 1663 | if (j->flags.userns) |
| 1664 | enter_user_namespace(j, userns_pipe_fds); |
| 1665 | |
Jorge Lucangeli Obes | df4bd35 | 2012-08-29 19:12:28 -0700 | [diff] [blame] | 1666 | /* |
| 1667 | * If we want to write to the jailed process' standard input, |
| 1668 | * set up the read end of the pipe. |
| 1669 | */ |
| 1670 | if (pstdin_fd) { |
Jorge Lucangeli Obes | 339a113 | 2013-02-15 16:53:47 -0800 | [diff] [blame] | 1671 | if (setup_and_dupe_pipe_end(stdin_fds, 0 /* read end */, |
| 1672 | STDIN_FILENO) < 0) |
Jorge Lucangeli Obes | df4bd35 | 2012-08-29 19:12:28 -0700 | [diff] [blame] | 1673 | die("failed to set up stdin pipe"); |
| 1674 | } |
| 1675 | |
Jorge Lucangeli Obes | 339a113 | 2013-02-15 16:53:47 -0800 | [diff] [blame] | 1676 | /* |
| 1677 | * If we want to read from the jailed process' standard output, |
| 1678 | * set up the write end of the pipe. |
| 1679 | */ |
| 1680 | if (pstdout_fd) { |
| 1681 | if (setup_and_dupe_pipe_end(stdout_fds, 1 /* write end */, |
| 1682 | STDOUT_FILENO) < 0) |
| 1683 | die("failed to set up stdout pipe"); |
| 1684 | } |
| 1685 | |
| 1686 | /* |
| 1687 | * If we want to read from the jailed process' standard error, |
| 1688 | * set up the write end of the pipe. |
| 1689 | */ |
| 1690 | if (pstderr_fd) { |
| 1691 | if (setup_and_dupe_pipe_end(stderr_fds, 1 /* write end */, |
| 1692 | STDERR_FILENO) < 0) |
| 1693 | die("failed to set up stderr pipe"); |
| 1694 | } |
| 1695 | |
Dylan Reid | 791f577 | 2015-09-14 20:02:42 -0700 | [diff] [blame] | 1696 | /* If running an init program, let it decide when/how to mount /proc. */ |
| 1697 | if (pid_namespace && !do_init) |
| 1698 | j->flags.remount_proc_ro = 0; |
| 1699 | |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1700 | if (use_preload) { |
| 1701 | /* Strip out flags that cannot be inherited across execve(2). */ |
| 1702 | minijail_preexec(j); |
| 1703 | } else { |
| 1704 | j->flags.pids = 0; |
| 1705 | } |
| 1706 | /* Jail this process, then execve() the target. */ |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1707 | minijail_enter(j); |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1708 | |
Yu-Hsi Chiang | 3e954ec | 2015-07-28 16:48:14 +0800 | [diff] [blame] | 1709 | if (pid_namespace && do_init) { |
Elly Jones | dd3e851 | 2012-01-23 15:13:38 -0500 | [diff] [blame] | 1710 | /* |
| 1711 | * pid namespace: this process will become init inside the new |
Yu-Hsi Chiang | 3e954ec | 2015-07-28 16:48:14 +0800 | [diff] [blame] | 1712 | * namespace. We don't want all programs we might exec to have |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1713 | * to know how to be init. Normally (do_init == 1) we fork off |
Yu-Hsi Chiang | 3e954ec | 2015-07-28 16:48:14 +0800 | [diff] [blame] | 1714 | * a child to actually run the program. If |do_init == 0|, we |
| 1715 | * let the program keep pid 1 and be init. |
Elly Jones | 761b741 | 2012-06-13 15:49:52 -0400 | [diff] [blame] | 1716 | * |
| 1717 | * If we're multithreaded, we'll probably deadlock here. See |
| 1718 | * WARNING above. |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1719 | */ |
| 1720 | child_pid = fork(); |
| 1721 | if (child_pid < 0) |
| 1722 | _exit(child_pid); |
| 1723 | else if (child_pid > 0) |
| 1724 | init(child_pid); /* never returns */ |
| 1725 | } |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1726 | |
Elly Jones | dd3e851 | 2012-01-23 15:13:38 -0500 | [diff] [blame] | 1727 | /* |
Jorge Lucangeli Obes | 5471450 | 2015-09-30 10:08:45 -0700 | [diff] [blame] | 1728 | * If we aren't pid-namespaced, or the jailed program asked to be init: |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1729 | * calling process |
| 1730 | * -> execve()-ing process |
| 1731 | * If we are: |
| 1732 | * calling process |
| 1733 | * -> init()-ing process |
| 1734 | * -> execve()-ing process |
| 1735 | */ |
| 1736 | _exit(execve(filename, argv, environ)); |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1737 | } |
| 1738 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 1739 | int API minijail_kill(struct minijail *j) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1740 | { |
| 1741 | int st; |
| 1742 | if (kill(j->initpid, SIGTERM)) |
| 1743 | return -errno; |
| 1744 | if (waitpid(j->initpid, &st, 0) < 0) |
| 1745 | return -errno; |
| 1746 | return st; |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1747 | } |
| 1748 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 1749 | int API minijail_wait(struct minijail *j) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1750 | { |
| 1751 | int st; |
| 1752 | if (waitpid(j->initpid, &st, 0) < 0) |
| 1753 | return -errno; |
Jorge Lucangeli Obes | 1530b74 | 2012-12-11 14:08:09 -0800 | [diff] [blame] | 1754 | |
Jorge Lucangeli Obes | c2c9bcc | 2012-05-01 09:30:24 -0700 | [diff] [blame] | 1755 | if (!WIFEXITED(st)) { |
Jorge Lucangeli Obes | 18d1eba | 2014-04-18 13:58:20 -0700 | [diff] [blame] | 1756 | int error_status = st; |
| 1757 | if (WIFSIGNALED(st)) { |
| 1758 | int signum = WTERMSIG(st); |
mukesh agrawal | c420a26 | 2013-06-11 17:22:42 -0700 | [diff] [blame] | 1759 | warn("child process %d received signal %d", |
Jorge Lucangeli Obes | 18d1eba | 2014-04-18 13:58:20 -0700 | [diff] [blame] | 1760 | j->initpid, signum); |
| 1761 | /* |
| 1762 | * We return MINIJAIL_ERR_JAIL if the process received |
| 1763 | * SIGSYS, which happens when a syscall is blocked by |
| 1764 | * seccomp filters. |
| 1765 | * If not, we do what bash(1) does: |
| 1766 | * $? = 128 + signum |
| 1767 | */ |
| 1768 | if (signum == SIGSYS) { |
| 1769 | error_status = MINIJAIL_ERR_JAIL; |
| 1770 | } else { |
| 1771 | error_status = 128 + signum; |
| 1772 | } |
| 1773 | } |
| 1774 | return error_status; |
Jorge Lucangeli Obes | c2c9bcc | 2012-05-01 09:30:24 -0700 | [diff] [blame] | 1775 | } |
Jorge Lucangeli Obes | 1530b74 | 2012-12-11 14:08:09 -0800 | [diff] [blame] | 1776 | |
| 1777 | int exit_status = WEXITSTATUS(st); |
| 1778 | if (exit_status != 0) |
mukesh agrawal | c420a26 | 2013-06-11 17:22:42 -0700 | [diff] [blame] | 1779 | info("child process %d exited with status %d", |
| 1780 | j->initpid, exit_status); |
Jorge Lucangeli Obes | 1530b74 | 2012-12-11 14:08:09 -0800 | [diff] [blame] | 1781 | |
| 1782 | return exit_status; |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1783 | } |
| 1784 | |
Will Drewry | 6ac9112 | 2011-10-21 16:38:58 -0500 | [diff] [blame] | 1785 | void API minijail_destroy(struct minijail *j) |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1786 | { |
Jorge Lucangeli Obes | 524c040 | 2012-01-17 11:30:23 -0800 | [diff] [blame] | 1787 | if (j->flags.seccomp_filter && j->filter_prog) { |
| 1788 | free(j->filter_prog->filter); |
| 1789 | free(j->filter_prog); |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1790 | } |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 1791 | while (j->mounts_head) { |
| 1792 | struct mountpoint *m = j->mounts_head; |
| 1793 | j->mounts_head = j->mounts_head->next; |
| 1794 | free(m->type); |
| 1795 | free(m->dest); |
| 1796 | free(m->src); |
| 1797 | free(m); |
Elly Jones | 51a5b6c | 2011-10-12 19:09:26 -0400 | [diff] [blame] | 1798 | } |
Dylan Reid | 648b220 | 2015-10-23 00:50:00 -0700 | [diff] [blame] | 1799 | j->mounts_tail = NULL; |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1800 | if (j->user) |
| 1801 | free(j->user); |
Jorge Lucangeli Obes | e81a52f | 2015-12-04 16:05:23 -0800 | [diff] [blame] | 1802 | if (j->suppl_gid_list) |
| 1803 | free(j->suppl_gid_list); |
Will Drewry | bee7ba7 | 2011-10-21 20:47:01 -0500 | [diff] [blame] | 1804 | if (j->chrootdir) |
| 1805 | free(j->chrootdir); |
Andrew Bresticker | eac2894 | 2015-11-11 16:04:46 -0800 | [diff] [blame] | 1806 | if (j->alt_syscall_table) |
| 1807 | free(j->alt_syscall_table); |
Elly Jones | e1749eb | 2011-10-07 13:54:59 -0400 | [diff] [blame] | 1808 | free(j); |
Elly Jones | cd7a904 | 2011-07-22 13:56:51 -0400 | [diff] [blame] | 1809 | } |