1 /* Copyright (c) 2012 The Chromium OS Authors. All rights reserved. 2 * Use of this source code is governed by a BSD-style license that can be 3 * found in the LICENSE file. 4 */ 5 6 /* 7 * The general pattern of use here: 8 * 1) Construct a minijail with minijail_new() 9 * 2) Apply the desired restrictions to it 10 * 3) Enter it, which locks the current process inside it, or: 11 * 3) Run a process inside it 12 * 4) Destroy it. 13 */ 14 15 #ifndef _LIBMINIJAIL_H_ 16 #define _LIBMINIJAIL_H_ 17 18 #include <stdint.h> 19 #include <sys/types.h> 20 21 #ifdef __cplusplus 22 extern "C" { 23 #endif 24 25 enum { 26 MINIJAIL_ERR_PRELOAD = 252, 27 MINIJAIL_ERR_JAIL = 253, 28 MINIJAIL_ERR_INIT = 254, 29 }; 30 31 struct minijail; 32 33 /* Allocates a new minijail with no restrictions. */ 34 struct minijail *minijail_new(void); 35 36 /* 37 * These functions add restrictions to the minijail. They are not applied until 38 * minijail_enter() is called. See the documentation in minijail0.1 for 39 * explanations in detail of what the restrictions do. 40 */ 41 void minijail_change_uid(struct minijail *j, uid_t uid); 42 void minijail_change_gid(struct minijail *j, gid_t gid); 43 /* Copies |list|. */ 44 void minijail_set_supplementary_gids(struct minijail *j, size_t size, 45 const gid_t *list); 46 void minijail_keep_supplementary_gids(struct minijail *j); 47 /* Stores user to change to and copies |user| for internal consistency. */ 48 int minijail_change_user(struct minijail *j, const char *user); 49 /* Does not take ownership of |group|. */ 50 int minijail_change_group(struct minijail *j, const char *group); 51 void minijail_use_seccomp(struct minijail *j); 52 void minijail_no_new_privs(struct minijail *j); 53 void minijail_use_seccomp_filter(struct minijail *j); 54 void minijail_set_seccomp_filter_tsync(struct minijail *j); 55 void minijail_parse_seccomp_filters(struct minijail *j, const char *path); 56 void minijail_parse_seccomp_filters_from_fd(struct minijail *j, int fd); 57 void minijail_log_seccomp_filter_failures(struct minijail *j); 58 /* 'minijail_use_caps' and 'minijail_capbset_drop' are mutually exclusive. */ 59 void minijail_use_caps(struct minijail *j, uint64_t capmask); 60 void minijail_capbset_drop(struct minijail *j, uint64_t capmask); 61 /* 'minijail_set_ambient_caps' requires 'minijail_use_caps'. */ 62 void minijail_set_ambient_caps(struct minijail *j); 63 void minijail_reset_signal_mask(struct minijail *j); 64 void minijail_namespace_vfs(struct minijail *j); 65 void minijail_namespace_enter_vfs(struct minijail *j, const char *ns_path); 66 void minijail_new_session_keyring(struct minijail *j); 67 void minijail_skip_setting_securebits(struct minijail *j, 68 uint64_t securebits_skip_mask); 69 70 /* 71 * This option is *dangerous* as it negates most of the functionality of 72 * minijail_namespace_vfs(). You very likely don't need this. 73 */ 74 void minijail_skip_remount_private(struct minijail *j); 75 void minijail_namespace_ipc(struct minijail *j); 76 void minijail_namespace_uts(struct minijail *j); 77 int minijail_namespace_set_hostname(struct minijail *j, const char *name); 78 void minijail_namespace_net(struct minijail *j); 79 void minijail_namespace_enter_net(struct minijail *j, const char *ns_path); 80 void minijail_namespace_cgroups(struct minijail *j); 81 /* Closes all open file descriptors after forking. */ 82 void minijail_close_open_fds(struct minijail *j); 83 /* 84 * Implies namespace_vfs and remount_proc_readonly. 85 * WARNING: this is NOT THREAD SAFE. See the block comment in </libminijail.c>. 86 */ 87 void minijail_namespace_pids(struct minijail *j); 88 void minijail_namespace_user(struct minijail *j); 89 void minijail_namespace_user_disable_setgroups(struct minijail *j); 90 int minijail_uidmap(struct minijail *j, const char *uidmap); 91 int minijail_gidmap(struct minijail *j, const char *gidmap); 92 void minijail_remount_proc_readonly(struct minijail *j); 93 void minijail_run_as_init(struct minijail *j); 94 int minijail_write_pid_file(struct minijail *j, const char *path); 95 void minijail_inherit_usergroups(struct minijail *j); 96 /* 97 * Changes the jailed process's syscall table to the alt_syscall table 98 * named |table|. 99 */ 100 int minijail_use_alt_syscall(struct minijail *j, const char *table); 101 102 /* Sets the given runtime limit. See getrlimit(2). */ 103 int minijail_rlimit(struct minijail *j, int type, uint32_t cur, uint32_t max); 104 105 /* 106 * Adds the jailed process to the cgroup given by |path|. |path| should be the 107 * full path to the cgroups "tasks" file. 108 * Example: /sys/fs/cgroup/cpu/jailed_procs/tasks adds to the "jailed_procs" cpu 109 * cgroup. 110 */ 111 int minijail_add_to_cgroup(struct minijail *j, const char *path); 112 113 /* 114 * Install signal handlers in the minijail process that forward received 115 * signals to the jailed child process. 116 */ 117 int minijail_forward_signals(struct minijail *j); 118 119 /* 120 * minijail_enter_chroot: enables chroot() restriction for @j 121 * @j minijail to apply restriction to 122 * @dir directory to chroot() to. Owned by caller. 123 * 124 * Enters @dir, binding all bind mounts specified with minijail_bind() into 125 * place. Requires @dir to contain all necessary directories for bind mounts 126 * (i.e., if you have requested a bind mount at /etc, /etc must exist in @dir.) 127 * 128 * Returns 0 on success. 129 */ 130 int minijail_enter_chroot(struct minijail *j, const char *dir); 131 int minijail_enter_pivot_root(struct minijail *j, const char *dir); 132 133 /* 134 * minijail_get_original_path: returns the path of a given file outside of the 135 * chroot. 136 * @j minijail to obtain the path from. 137 * @chroot_path path inside of the chroot() to. 138 * 139 * When executing a binary in a chroot or pivot_root, return path to the binary 140 * outside of the chroot. 141 * 142 * Returns a string containing the path. This must be freed by the caller. 143 */ 144 char *minijail_get_original_path(struct minijail *j, const char *chroot_path); 145 146 /* 147 * minijail_mount_tmp: enables mounting of a 64M tmpfs filesystem on /tmp. 148 * As be rules of bind mounts, /tmp must exist in chroot. 149 */ 150 void minijail_mount_tmp(struct minijail *j); 151 152 /* 153 * minijail_mount_tmp_size: enables mounting of a tmpfs filesystem on /tmp. 154 * As be rules of bind mounts, /tmp must exist in chroot. Size is in bytes. 155 */ 156 void minijail_mount_tmp_size(struct minijail *j, size_t size); 157 158 /* 159 * minijail_mount_with_data: when entering minijail @j, 160 * mounts @src at @dst with @flags and @data. 161 * @j minijail to bind inside 162 * @src source to bind 163 * @dest location to bind (inside chroot) 164 * @type type of filesystem 165 * @flags flags passed to mount 166 * @data data arguments passed to mount(2), e.g. "mode=755" 167 * 168 * This may be called multiple times; all mounts will be applied in the order 169 * of minijail_mount() calls. 170 */ 171 int minijail_mount_with_data(struct minijail *j, const char *src, 172 const char *dest, const char *type, 173 unsigned long flags, const char *data); 174 175 /* 176 * minijail_mount: when entering minijail @j, mounts @src at @dst with @flags 177 * @j minijail to bind inside 178 * @src source to bind 179 * @dest location to bind (inside chroot) 180 * @type type of filesystem 181 * @flags flags passed to mount 182 * 183 * This may be called multiple times; all mounts will be applied in the order 184 * of minijail_mount() calls. 185 */ 186 int minijail_mount(struct minijail *j, const char *src, const char *dest, 187 const char *type, unsigned long flags); 188 189 /* 190 * minijail_bind: bind-mounts @src into @j as @dest, optionally writeable 191 * @j minijail to bind inside 192 * @src source to bind 193 * @dest location to bind (inside chroot) 194 * @writeable 1 if the bind mount should be writeable 195 * 196 * This may be called multiple times; all bindings will be applied in the order 197 * of minijail_bind() calls. 198 */ 199 int minijail_bind(struct minijail *j, const char *src, const char *dest, 200 int writeable); 201 202 /* 203 * Lock this process into the given minijail. Note that this procedure cannot 204 * fail, since there is no way to undo privilege-dropping; therefore, if any 205 * part of the privilege-drop fails, minijail_enter() will abort the entire 206 * process. 207 * 208 * Some restrictions cannot be enabled this way (pid namespaces) and attempting 209 * to do so will cause an abort. 210 */ 211 void minijail_enter(const struct minijail *j); 212 213 /* 214 * Run the specified command in the given minijail, execve(2)-style. This is 215 * required if minijail_namespace_pids() was used. 216 */ 217 int minijail_run(struct minijail *j, const char *filename, 218 char *const argv[]); 219 220 /* 221 * Run the specified command in the given minijail, execve(2)-style. 222 * Used with static binaries, or on systems without support for LD_PRELOAD. 223 */ 224 int minijail_run_no_preload(struct minijail *j, const char *filename, 225 char *const argv[]); 226 227 /* 228 * Run the specified command in the given minijail, execve(2)-style. 229 * Update |*pchild_pid| with the pid of the child. 230 */ 231 int minijail_run_pid(struct minijail *j, const char *filename, 232 char *const argv[], pid_t *pchild_pid); 233 234 /* 235 * Run the specified command in the given minijail, execve(2)-style. 236 * Update |*pstdin_fd| with a fd that allows writing to the child's 237 * standard input. 238 */ 239 int minijail_run_pipe(struct minijail *j, const char *filename, 240 char *const argv[], int *pstdin_fd); 241 242 /* 243 * Run the specified command in the given minijail, execve(2)-style. 244 * Update |*pchild_pid| with the pid of the child. 245 * Update |*pstdin_fd| with a fd that allows writing to the child's 246 * standard input. 247 * Update |*pstdout_fd| with a fd that allows reading from the child's 248 * standard output. 249 * Update |*pstderr_fd| with a fd that allows reading from the child's 250 * standard error. 251 */ 252 int minijail_run_pid_pipes(struct minijail *j, const char *filename, 253 char *const argv[], pid_t *pchild_pid, 254 int *pstdin_fd, int *pstdout_fd, int *pstderr_fd); 255 256 /* 257 * Run the specified command in the given minijail, execve(2)-style. 258 * Update |*pchild_pid| with the pid of the child. 259 * Update |*pstdin_fd| with a fd that allows writing to the child's 260 * standard input. 261 * Update |*pstdout_fd| with a fd that allows reading from the child's 262 * standard output. 263 * Update |*pstderr_fd| with a fd that allows reading from the child's 264 * standard error. 265 * Used with static binaries, or on systems without support for LD_PRELOAD. 266 */ 267 int minijail_run_pid_pipes_no_preload(struct minijail *j, const char *filename, 268 char *const argv[], pid_t *pchild_pid, 269 int *pstdin_fd, int *pstdout_fd, 270 int *pstderr_fd); 271 272 /* 273 * Kill the specified minijail. The minijail must have been created with pid 274 * namespacing; if it was, all processes inside it are atomically killed. 275 */ 276 int minijail_kill(struct minijail *j); 277 278 /* 279 * Wait for all processes in the specified minijail to exit. Returns the exit 280 * status of the _first_ process spawned in the jail. 281 */ 282 int minijail_wait(struct minijail *j); 283 284 /* 285 * Frees the given minijail. It does not matter if the process is inside the 286 * minijail or not. 287 */ 288 void minijail_destroy(struct minijail *j); 289 290 #ifdef __cplusplus 291 }; /* extern "C" */ 292 #endif 293 294 #endif /* !_LIBMINIJAIL_H_ */ 295