1 // SPDX-License-Identifier: GPL-2.0 2 3 /* 4 * Copyright (C) 2020 Google LLC. 5 */ 6 7 #include <linux/filter.h> 8 #include <linux/bpf.h> 9 #include <linux/btf.h> 10 #include <linux/binfmts.h> 11 #include <linux/lsm_hooks.h> 12 #include <linux/bpf_lsm.h> 13 #include <linux/kallsyms.h> 14 #include <linux/bpf_verifier.h> 15 #include <net/bpf_sk_storage.h> 16 #include <linux/bpf_local_storage.h> 17 #include <linux/btf_ids.h> 18 #include <linux/ima.h> 19 #include <linux/bpf-cgroup.h> 20 21 /* For every LSM hook that allows attachment of BPF programs, declare a nop 22 * function where a BPF program can be attached. 23 */ 24 #define LSM_HOOK(RET, DEFAULT, NAME, ...) \ 25 noinline RET bpf_lsm_##NAME(__VA_ARGS__) \ 26 { \ 27 return DEFAULT; \ 28 } 29 30 #include <linux/lsm_hook_defs.h> 31 #undef LSM_HOOK 32 33 #define LSM_HOOK(RET, DEFAULT, NAME, ...) BTF_ID(func, bpf_lsm_##NAME) 34 BTF_SET_START(bpf_lsm_hooks) 35 #include <linux/lsm_hook_defs.h> 36 #undef LSM_HOOK 37 BTF_SET_END(bpf_lsm_hooks) 38 39 /* List of LSM hooks that should operate on 'current' cgroup regardless 40 * of function signature. 41 */ 42 BTF_SET_START(bpf_lsm_current_hooks) 43 /* operate on freshly allocated sk without any cgroup association */ 44 #ifdef CONFIG_SECURITY_NETWORK 45 BTF_ID(func, bpf_lsm_sk_alloc_security) 46 BTF_ID(func, bpf_lsm_sk_free_security) 47 #endif 48 BTF_SET_END(bpf_lsm_current_hooks) 49 50 /* List of LSM hooks that trigger while the socket is properly locked. 51 */ 52 BTF_SET_START(bpf_lsm_locked_sockopt_hooks) 53 #ifdef CONFIG_SECURITY_NETWORK 54 BTF_ID(func, bpf_lsm_socket_sock_rcv_skb) 55 BTF_ID(func, bpf_lsm_sock_graft) 56 BTF_ID(func, bpf_lsm_inet_csk_clone) 57 BTF_ID(func, bpf_lsm_inet_conn_established) 58 #endif 59 BTF_SET_END(bpf_lsm_locked_sockopt_hooks) 60 61 /* List of LSM hooks that trigger while the socket is _not_ locked, 62 * but it's ok to call bpf_{g,s}etsockopt because the socket is still 63 * in the early init phase. 64 */ 65 BTF_SET_START(bpf_lsm_unlocked_sockopt_hooks) 66 #ifdef CONFIG_SECURITY_NETWORK 67 BTF_ID(func, bpf_lsm_socket_post_create) 68 BTF_ID(func, bpf_lsm_socket_socketpair) 69 #endif 70 BTF_SET_END(bpf_lsm_unlocked_sockopt_hooks) 71 72 #ifdef CONFIG_CGROUP_BPF 73 void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog, 74 bpf_func_t *bpf_func) 75 { 76 const struct btf_param *args __maybe_unused; 77 78 if (btf_type_vlen(prog->aux->attach_func_proto) < 1 || 79 btf_id_set_contains(&bpf_lsm_current_hooks, 80 prog->aux->attach_btf_id)) { 81 *bpf_func = __cgroup_bpf_run_lsm_current; 82 return; 83 } 84 85 #ifdef CONFIG_NET 86 args = btf_params(prog->aux->attach_func_proto); 87 88 if (args[0].type == btf_sock_ids[BTF_SOCK_TYPE_SOCKET]) 89 *bpf_func = __cgroup_bpf_run_lsm_socket; 90 else if (args[0].type == btf_sock_ids[BTF_SOCK_TYPE_SOCK]) 91 *bpf_func = __cgroup_bpf_run_lsm_sock; 92 else 93 #endif 94 *bpf_func = __cgroup_bpf_run_lsm_current; 95 } 96 #endif 97 98 int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog, 99 const struct bpf_prog *prog) 100 { 101 if (!prog->gpl_compatible) { 102 bpf_log(vlog, 103 "LSM programs must have a GPL compatible license\n"); 104 return -EINVAL; 105 } 106 107 if (!btf_id_set_contains(&bpf_lsm_hooks, prog->aux->attach_btf_id)) { 108 bpf_log(vlog, "attach_btf_id %u points to wrong type name %s\n", 109 prog->aux->attach_btf_id, prog->aux->attach_func_name); 110 return -EINVAL; 111 } 112 113 return 0; 114 } 115 116 /* Mask for all the currently supported BPRM option flags */ 117 #define BPF_F_BRPM_OPTS_MASK BPF_F_BPRM_SECUREEXEC 118 119 BPF_CALL_2(bpf_bprm_opts_set, struct linux_binprm *, bprm, u64, flags) 120 { 121 if (flags & ~BPF_F_BRPM_OPTS_MASK) 122 return -EINVAL; 123 124 bprm->secureexec = (flags & BPF_F_BPRM_SECUREEXEC); 125 return 0; 126 } 127 128 BTF_ID_LIST_SINGLE(bpf_bprm_opts_set_btf_ids, struct, linux_binprm) 129 130 static const struct bpf_func_proto bpf_bprm_opts_set_proto = { 131 .func = bpf_bprm_opts_set, 132 .gpl_only = false, 133 .ret_type = RET_INTEGER, 134 .arg1_type = ARG_PTR_TO_BTF_ID, 135 .arg1_btf_id = &bpf_bprm_opts_set_btf_ids[0], 136 .arg2_type = ARG_ANYTHING, 137 }; 138 139 BPF_CALL_3(bpf_ima_inode_hash, struct inode *, inode, void *, dst, u32, size) 140 { 141 return ima_inode_hash(inode, dst, size); 142 } 143 144 static bool bpf_ima_inode_hash_allowed(const struct bpf_prog *prog) 145 { 146 return bpf_lsm_is_sleepable_hook(prog->aux->attach_btf_id); 147 } 148 149 BTF_ID_LIST_SINGLE(bpf_ima_inode_hash_btf_ids, struct, inode) 150 151 static const struct bpf_func_proto bpf_ima_inode_hash_proto = { 152 .func = bpf_ima_inode_hash, 153 .gpl_only = false, 154 .might_sleep = true, 155 .ret_type = RET_INTEGER, 156 .arg1_type = ARG_PTR_TO_BTF_ID, 157 .arg1_btf_id = &bpf_ima_inode_hash_btf_ids[0], 158 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 159 .arg3_type = ARG_CONST_SIZE, 160 .allowed = bpf_ima_inode_hash_allowed, 161 }; 162 163 BPF_CALL_3(bpf_ima_file_hash, struct file *, file, void *, dst, u32, size) 164 { 165 return ima_file_hash(file, dst, size); 166 } 167 168 BTF_ID_LIST_SINGLE(bpf_ima_file_hash_btf_ids, struct, file) 169 170 static const struct bpf_func_proto bpf_ima_file_hash_proto = { 171 .func = bpf_ima_file_hash, 172 .gpl_only = false, 173 .might_sleep = true, 174 .ret_type = RET_INTEGER, 175 .arg1_type = ARG_PTR_TO_BTF_ID, 176 .arg1_btf_id = &bpf_ima_file_hash_btf_ids[0], 177 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 178 .arg3_type = ARG_CONST_SIZE, 179 .allowed = bpf_ima_inode_hash_allowed, 180 }; 181 182 BPF_CALL_1(bpf_get_attach_cookie, void *, ctx) 183 { 184 struct bpf_trace_run_ctx *run_ctx; 185 186 run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx); 187 return run_ctx->bpf_cookie; 188 } 189 190 static const struct bpf_func_proto bpf_get_attach_cookie_proto = { 191 .func = bpf_get_attach_cookie, 192 .gpl_only = false, 193 .ret_type = RET_INTEGER, 194 .arg1_type = ARG_PTR_TO_CTX, 195 }; 196 197 static const struct bpf_func_proto * 198 bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 199 { 200 const struct bpf_func_proto *func_proto; 201 202 if (prog->expected_attach_type == BPF_LSM_CGROUP) { 203 func_proto = cgroup_common_func_proto(func_id, prog); 204 if (func_proto) 205 return func_proto; 206 } 207 208 switch (func_id) { 209 case BPF_FUNC_inode_storage_get: 210 return &bpf_inode_storage_get_proto; 211 case BPF_FUNC_inode_storage_delete: 212 return &bpf_inode_storage_delete_proto; 213 #ifdef CONFIG_NET 214 case BPF_FUNC_sk_storage_get: 215 return &bpf_sk_storage_get_proto; 216 case BPF_FUNC_sk_storage_delete: 217 return &bpf_sk_storage_delete_proto; 218 #endif /* CONFIG_NET */ 219 case BPF_FUNC_spin_lock: 220 return &bpf_spin_lock_proto; 221 case BPF_FUNC_spin_unlock: 222 return &bpf_spin_unlock_proto; 223 case BPF_FUNC_bprm_opts_set: 224 return &bpf_bprm_opts_set_proto; 225 case BPF_FUNC_ima_inode_hash: 226 return &bpf_ima_inode_hash_proto; 227 case BPF_FUNC_ima_file_hash: 228 return &bpf_ima_file_hash_proto; 229 case BPF_FUNC_get_attach_cookie: 230 return bpf_prog_has_trampoline(prog) ? &bpf_get_attach_cookie_proto : NULL; 231 #ifdef CONFIG_NET 232 case BPF_FUNC_setsockopt: 233 if (prog->expected_attach_type != BPF_LSM_CGROUP) 234 return NULL; 235 if (btf_id_set_contains(&bpf_lsm_locked_sockopt_hooks, 236 prog->aux->attach_btf_id)) 237 return &bpf_sk_setsockopt_proto; 238 if (btf_id_set_contains(&bpf_lsm_unlocked_sockopt_hooks, 239 prog->aux->attach_btf_id)) 240 return &bpf_unlocked_sk_setsockopt_proto; 241 return NULL; 242 case BPF_FUNC_getsockopt: 243 if (prog->expected_attach_type != BPF_LSM_CGROUP) 244 return NULL; 245 if (btf_id_set_contains(&bpf_lsm_locked_sockopt_hooks, 246 prog->aux->attach_btf_id)) 247 return &bpf_sk_getsockopt_proto; 248 if (btf_id_set_contains(&bpf_lsm_unlocked_sockopt_hooks, 249 prog->aux->attach_btf_id)) 250 return &bpf_unlocked_sk_getsockopt_proto; 251 return NULL; 252 #endif 253 default: 254 return tracing_prog_func_proto(func_id, prog); 255 } 256 } 257 258 /* The set of hooks which are called without pagefaults disabled and are allowed 259 * to "sleep" and thus can be used for sleepable BPF programs. 260 */ 261 BTF_SET_START(sleepable_lsm_hooks) 262 BTF_ID(func, bpf_lsm_bpf) 263 BTF_ID(func, bpf_lsm_bpf_map) 264 BTF_ID(func, bpf_lsm_bpf_map_alloc_security) 265 BTF_ID(func, bpf_lsm_bpf_map_free_security) 266 BTF_ID(func, bpf_lsm_bpf_prog) 267 BTF_ID(func, bpf_lsm_bprm_check_security) 268 BTF_ID(func, bpf_lsm_bprm_committed_creds) 269 BTF_ID(func, bpf_lsm_bprm_committing_creds) 270 BTF_ID(func, bpf_lsm_bprm_creds_for_exec) 271 BTF_ID(func, bpf_lsm_bprm_creds_from_file) 272 BTF_ID(func, bpf_lsm_capget) 273 BTF_ID(func, bpf_lsm_capset) 274 BTF_ID(func, bpf_lsm_cred_prepare) 275 BTF_ID(func, bpf_lsm_file_ioctl) 276 BTF_ID(func, bpf_lsm_file_lock) 277 BTF_ID(func, bpf_lsm_file_open) 278 BTF_ID(func, bpf_lsm_file_receive) 279 280 #ifdef CONFIG_SECURITY_NETWORK 281 BTF_ID(func, bpf_lsm_inet_conn_established) 282 #endif /* CONFIG_SECURITY_NETWORK */ 283 284 BTF_ID(func, bpf_lsm_inode_create) 285 BTF_ID(func, bpf_lsm_inode_free_security) 286 BTF_ID(func, bpf_lsm_inode_getattr) 287 BTF_ID(func, bpf_lsm_inode_getxattr) 288 BTF_ID(func, bpf_lsm_inode_mknod) 289 BTF_ID(func, bpf_lsm_inode_need_killpriv) 290 BTF_ID(func, bpf_lsm_inode_post_setxattr) 291 BTF_ID(func, bpf_lsm_inode_readlink) 292 BTF_ID(func, bpf_lsm_inode_rename) 293 BTF_ID(func, bpf_lsm_inode_rmdir) 294 BTF_ID(func, bpf_lsm_inode_setattr) 295 BTF_ID(func, bpf_lsm_inode_setxattr) 296 BTF_ID(func, bpf_lsm_inode_symlink) 297 BTF_ID(func, bpf_lsm_inode_unlink) 298 BTF_ID(func, bpf_lsm_kernel_module_request) 299 BTF_ID(func, bpf_lsm_kernel_read_file) 300 BTF_ID(func, bpf_lsm_kernfs_init_security) 301 302 #ifdef CONFIG_KEYS 303 BTF_ID(func, bpf_lsm_key_free) 304 #endif /* CONFIG_KEYS */ 305 306 BTF_ID(func, bpf_lsm_mmap_file) 307 BTF_ID(func, bpf_lsm_netlink_send) 308 BTF_ID(func, bpf_lsm_path_notify) 309 BTF_ID(func, bpf_lsm_release_secctx) 310 BTF_ID(func, bpf_lsm_sb_alloc_security) 311 BTF_ID(func, bpf_lsm_sb_eat_lsm_opts) 312 BTF_ID(func, bpf_lsm_sb_kern_mount) 313 BTF_ID(func, bpf_lsm_sb_mount) 314 BTF_ID(func, bpf_lsm_sb_remount) 315 BTF_ID(func, bpf_lsm_sb_set_mnt_opts) 316 BTF_ID(func, bpf_lsm_sb_show_options) 317 BTF_ID(func, bpf_lsm_sb_statfs) 318 BTF_ID(func, bpf_lsm_sb_umount) 319 BTF_ID(func, bpf_lsm_settime) 320 321 #ifdef CONFIG_SECURITY_NETWORK 322 BTF_ID(func, bpf_lsm_socket_accept) 323 BTF_ID(func, bpf_lsm_socket_bind) 324 BTF_ID(func, bpf_lsm_socket_connect) 325 BTF_ID(func, bpf_lsm_socket_create) 326 BTF_ID(func, bpf_lsm_socket_getpeername) 327 BTF_ID(func, bpf_lsm_socket_getpeersec_dgram) 328 BTF_ID(func, bpf_lsm_socket_getsockname) 329 BTF_ID(func, bpf_lsm_socket_getsockopt) 330 BTF_ID(func, bpf_lsm_socket_listen) 331 BTF_ID(func, bpf_lsm_socket_post_create) 332 BTF_ID(func, bpf_lsm_socket_recvmsg) 333 BTF_ID(func, bpf_lsm_socket_sendmsg) 334 BTF_ID(func, bpf_lsm_socket_shutdown) 335 BTF_ID(func, bpf_lsm_socket_socketpair) 336 #endif /* CONFIG_SECURITY_NETWORK */ 337 338 BTF_ID(func, bpf_lsm_syslog) 339 BTF_ID(func, bpf_lsm_task_alloc) 340 BTF_ID(func, bpf_lsm_current_getsecid_subj) 341 BTF_ID(func, bpf_lsm_task_getsecid_obj) 342 BTF_ID(func, bpf_lsm_task_prctl) 343 BTF_ID(func, bpf_lsm_task_setscheduler) 344 BTF_ID(func, bpf_lsm_task_to_inode) 345 BTF_ID(func, bpf_lsm_userns_create) 346 BTF_SET_END(sleepable_lsm_hooks) 347 348 BTF_SET_START(untrusted_lsm_hooks) 349 BTF_ID(func, bpf_lsm_bpf_map_free_security) 350 BTF_ID(func, bpf_lsm_bpf_prog_alloc_security) 351 BTF_ID(func, bpf_lsm_bpf_prog_free_security) 352 BTF_ID(func, bpf_lsm_file_alloc_security) 353 BTF_ID(func, bpf_lsm_file_free_security) 354 #ifdef CONFIG_SECURITY_NETWORK 355 BTF_ID(func, bpf_lsm_sk_alloc_security) 356 BTF_ID(func, bpf_lsm_sk_free_security) 357 #endif /* CONFIG_SECURITY_NETWORK */ 358 BTF_ID(func, bpf_lsm_task_free) 359 BTF_SET_END(untrusted_lsm_hooks) 360 361 bool bpf_lsm_is_sleepable_hook(u32 btf_id) 362 { 363 return btf_id_set_contains(&sleepable_lsm_hooks, btf_id); 364 } 365 366 bool bpf_lsm_is_trusted(const struct bpf_prog *prog) 367 { 368 return !btf_id_set_contains(&untrusted_lsm_hooks, prog->aux->attach_btf_id); 369 } 370 371 const struct bpf_prog_ops lsm_prog_ops = { 372 }; 373 374 const struct bpf_verifier_ops lsm_verifier_ops = { 375 .get_func_proto = bpf_lsm_func_proto, 376 .is_valid_access = btf_ctx_access, 377 }; 378