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 void minijail_reset_signal_mask(struct minijail *j); 62 void minijail_namespace_vfs(struct minijail *j); 63 void minijail_namespace_enter_vfs(struct minijail *j, const char *ns_path); 64 void minijail_new_session_keyring(struct minijail *j); 65 66 /* 67 * This option is *dangerous* as it negates most of the functionality of 68 * minijail_namespace_vfs(). You very likely don't need this. 69 */ 70 void minijail_skip_remount_private(struct minijail *j); 71 void minijail_namespace_ipc(struct minijail *j); 72 void minijail_namespace_net(struct minijail *j); 73 void minijail_namespace_enter_net(struct minijail *j, const char *ns_path); 74 void minijail_namespace_cgroups(struct minijail *j); 75 /* Closes all open file descriptors after forking. */ 76 void minijail_close_open_fds(struct minijail *j); 77 /* 78 * Implies namespace_vfs and remount_proc_readonly. 79 * WARNING: this is NOT THREAD SAFE. See the block comment in </libminijail.c>. 80 */ 81 void minijail_namespace_pids(struct minijail *j); 82 void minijail_namespace_user(struct minijail *j); 83 void minijail_namespace_user_disable_setgroups(struct minijail *j); 84 int minijail_uidmap(struct minijail *j, const char *uidmap); 85 int minijail_gidmap(struct minijail *j, const char *gidmap); 86 void minijail_remount_proc_readonly(struct minijail *j); 87 void minijail_run_as_init(struct minijail *j); 88 int minijail_write_pid_file(struct minijail *j, const char *path); 89 void minijail_inherit_usergroups(struct minijail *j); 90 /* 91 * Changes the jailed process's syscall table to the alt_syscall table 92 * named |table|. 93 */ 94 int minijail_use_alt_syscall(struct minijail *j, const char *table); 95 96 /* 97 * Adds the jailed process to the cgroup given by |path|. |path| should be the 98 * full path to the cgroups "tasks" file. 99 * Example: /sys/fs/cgroup/cpu/jailed_procs/tasks adds to the "jailed_procs" cpu 100 * cgroup. 101 */ 102 int minijail_add_to_cgroup(struct minijail *j, const char *path); 103 104 /* 105 * minijail_enter_chroot: enables chroot() restriction for @j 106 * @j minijail to apply restriction to 107 * @dir directory to chroot() to. Owned by caller. 108 * 109 * Enters @dir, binding all bind mounts specified with minijail_bind() into 110 * place. Requires @dir to contain all necessary directories for bind mounts 111 * (i.e., if you have requested a bind mount at /etc, /etc must exist in @dir.) 112 * 113 * Returns 0 on success. 114 */ 115 int minijail_enter_chroot(struct minijail *j, const char *dir); 116 int minijail_enter_pivot_root(struct minijail *j, const char *dir); 117 118 /* 119 * minijail_get_original_path: returns the path of a given file outside of the 120 * chroot. 121 * @j minijail to obtain the path from. 122 * @chroot_path path inside of the chroot() to. 123 * 124 * When executing a binary in a chroot or pivot_root, return path to the binary 125 * outside of the chroot. 126 * 127 * Returns a string containing the path. This must be freed by the caller. 128 */ 129 char *minijail_get_original_path(struct minijail *j, const char *chroot_path); 130 131 /* 132 * minijail_mount_tmp: enables mounting of a 64M tmpfs filesystem on /tmp. 133 * As be rules of bind mounts, /tmp must exist in chroot. 134 */ 135 void minijail_mount_tmp(struct minijail *j); 136 137 /* 138 * minijail_mount_tmp_size: enables mounting of a tmpfs filesystem on /tmp. 139 * As be rules of bind mounts, /tmp must exist in chroot. Size is in bytes. 140 */ 141 void minijail_mount_tmp_size(struct minijail *j, size_t size); 142 143 /* 144 * minijail_mount_with_data: when entering minijail @j, 145 * mounts @src at @dst with @flags and @data. 146 * @j minijail to bind inside 147 * @src source to bind 148 * @dest location to bind (inside chroot) 149 * @type type of filesystem 150 * @flags flags passed to mount 151 * @data data arguments passed to mount(2), e.g. "mode=755" 152 * 153 * This may be called multiple times; all mounts will be applied in the order 154 * of minijail_mount() calls. 155 */ 156 int minijail_mount_with_data(struct minijail *j, const char *src, 157 const char *dest, const char *type, 158 unsigned long flags, const char *data); 159 160 /* 161 * minijail_mount: when entering minijail @j, mounts @src at @dst with @flags 162 * @j minijail to bind inside 163 * @src source to bind 164 * @dest location to bind (inside chroot) 165 * @type type of filesystem 166 * @flags flags passed to mount 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(struct minijail *j, const char *src, const char *dest, 172 const char *type, unsigned long flags); 173 174 /* 175 * minijail_bind: bind-mounts @src into @j as @dest, optionally writeable 176 * @j minijail to bind inside 177 * @src source to bind 178 * @dest location to bind (inside chroot) 179 * @writeable 1 if the bind mount should be writeable 180 * 181 * This may be called multiple times; all bindings will be applied in the order 182 * of minijail_bind() calls. 183 */ 184 int minijail_bind(struct minijail *j, const char *src, const char *dest, 185 int writeable); 186 187 /* 188 * Lock this process into the given minijail. Note that this procedure cannot 189 * fail, since there is no way to undo privilege-dropping; therefore, if any 190 * part of the privilege-drop fails, minijail_enter() will abort the entire 191 * process. 192 * 193 * Some restrictions cannot be enabled this way (pid namespaces) and attempting 194 * to do so will cause an abort. 195 */ 196 void minijail_enter(const struct minijail *j); 197 198 /* 199 * Run the specified command in the given minijail, execve(2)-style. This is 200 * required if minijail_namespace_pids() was used. 201 */ 202 int minijail_run(struct minijail *j, const char *filename, 203 char *const argv[]); 204 205 /* 206 * Run the specified command in the given minijail, execve(2)-style. 207 * Used with static binaries, or on systems without support for LD_PRELOAD. 208 */ 209 int minijail_run_no_preload(struct minijail *j, const char *filename, 210 char *const argv[]); 211 212 /* 213 * Run the specified command in the given minijail, execve(2)-style. 214 * Update |*pchild_pid| with the pid of the child. 215 */ 216 int minijail_run_pid(struct minijail *j, const char *filename, 217 char *const argv[], pid_t *pchild_pid); 218 219 /* 220 * Run the specified command in the given minijail, execve(2)-style. 221 * Update |*pstdin_fd| with a fd that allows writing to the child's 222 * standard input. 223 */ 224 int minijail_run_pipe(struct minijail *j, const char *filename, 225 char *const argv[], int *pstdin_fd); 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 * Update |*pstdin_fd| with a fd that allows writing to the child's 231 * standard input. 232 * Update |*pstdout_fd| with a fd that allows reading from the child's 233 * standard output. 234 * Update |*pstderr_fd| with a fd that allows reading from the child's 235 * standard error. 236 */ 237 int minijail_run_pid_pipes(struct minijail *j, const char *filename, 238 char *const argv[], pid_t *pchild_pid, 239 int *pstdin_fd, int *pstdout_fd, int *pstderr_fd); 240 241 /* 242 * Run the specified command in the given minijail, execve(2)-style. 243 * Update |*pchild_pid| with the pid of the child. 244 * Update |*pstdin_fd| with a fd that allows writing to the child's 245 * standard input. 246 * Update |*pstdout_fd| with a fd that allows reading from the child's 247 * standard output. 248 * Update |*pstderr_fd| with a fd that allows reading from the child's 249 * standard error. 250 * Used with static binaries, or on systems without support for LD_PRELOAD. 251 */ 252 int minijail_run_pid_pipes_no_preload(struct minijail *j, const char *filename, 253 char *const argv[], pid_t *pchild_pid, 254 int *pstdin_fd, int *pstdout_fd, 255 int *pstderr_fd); 256 257 /* 258 * Kill the specified minijail. The minijail must have been created with pid 259 * namespacing; if it was, all processes inside it are atomically killed. 260 */ 261 int minijail_kill(struct minijail *j); 262 263 /* 264 * Wait for all processes in the specified minijail to exit. Returns the exit 265 * status of the _first_ process spawned in the jail. 266 */ 267 int minijail_wait(struct minijail *j); 268 269 /* 270 * Frees the given minijail. It does not matter if the process is inside the 271 * minijail or not. 272 */ 273 void minijail_destroy(struct minijail *j); 274 275 #ifdef __cplusplus 276 }; /* extern "C" */ 277 #endif 278 279 #endif /* !_LIBMINIJAIL_H_ */ 280
