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, ...) \ 25noinline 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) 34BTF_SET_START(bpf_lsm_hooks) 35#include <linux/lsm_hook_defs.h> 36#undef LSM_HOOK 37BTF_SET_END(bpf_lsm_hooks) 38 39/* List of LSM hooks that should operate on 'current' cgroup regardless 40 * of function signature. 41 */ 42BTF_SET_START(bpf_lsm_current_hooks) 43/* operate on freshly allocated sk without any cgroup association */ 44#ifdef CONFIG_SECURITY_NETWORK 45BTF_ID(func, bpf_lsm_sk_alloc_security) 46BTF_ID(func, bpf_lsm_sk_free_security) 47#endif 48BTF_SET_END(bpf_lsm_current_hooks) 49 50/* List of LSM hooks that trigger while the socket is properly locked. 51 */ 52BTF_SET_START(bpf_lsm_locked_sockopt_hooks) 53#ifdef CONFIG_SECURITY_NETWORK 54BTF_ID(func, bpf_lsm_sock_graft) 55BTF_ID(func, bpf_lsm_inet_csk_clone) 56BTF_ID(func, bpf_lsm_inet_conn_established) 57#endif 58BTF_SET_END(bpf_lsm_locked_sockopt_hooks) 59 60/* List of LSM hooks that trigger while the socket is _not_ locked, 61 * but it's ok to call bpf_{g,s}etsockopt because the socket is still 62 * in the early init phase. 63 */ 64BTF_SET_START(bpf_lsm_unlocked_sockopt_hooks) 65#ifdef CONFIG_SECURITY_NETWORK 66BTF_ID(func, bpf_lsm_socket_post_create) 67BTF_ID(func, bpf_lsm_socket_socketpair) 68#endif 69BTF_SET_END(bpf_lsm_unlocked_sockopt_hooks) 70 71#ifdef CONFIG_CGROUP_BPF 72void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog, 73 bpf_func_t *bpf_func) 74{ 75 const struct btf_param *args __maybe_unused; 76 77 if (btf_type_vlen(prog->aux->attach_func_proto) < 1 || 78 btf_id_set_contains(&bpf_lsm_current_hooks, 79 prog->aux->attach_btf_id)) { 80 *bpf_func = __cgroup_bpf_run_lsm_current; 81 return; 82 } 83 84#ifdef CONFIG_NET 85 args = btf_params(prog->aux->attach_func_proto); 86 87 if (args[0].type == btf_sock_ids[BTF_SOCK_TYPE_SOCKET]) 88 *bpf_func = __cgroup_bpf_run_lsm_socket; 89 else if (args[0].type == btf_sock_ids[BTF_SOCK_TYPE_SOCK]) 90 *bpf_func = __cgroup_bpf_run_lsm_sock; 91 else 92#endif 93 *bpf_func = __cgroup_bpf_run_lsm_current; 94} 95#endif 96 97int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog, 98 const struct bpf_prog *prog) 99{ 100 if (!prog->gpl_compatible) { 101 bpf_log(vlog, 102 "LSM programs must have a GPL compatible license\n"); 103 return -EINVAL; 104 } 105 106 if (!btf_id_set_contains(&bpf_lsm_hooks, prog->aux->attach_btf_id)) { 107 bpf_log(vlog, "attach_btf_id %u points to wrong type name %s\n", 108 prog->aux->attach_btf_id, prog->aux->attach_func_name); 109 return -EINVAL; 110 } 111 112 return 0; 113} 114 115/* Mask for all the currently supported BPRM option flags */ 116#define BPF_F_BRPM_OPTS_MASK BPF_F_BPRM_SECUREEXEC 117 118BPF_CALL_2(bpf_bprm_opts_set, struct linux_binprm *, bprm, u64, flags) 119{ 120 if (flags & ~BPF_F_BRPM_OPTS_MASK) 121 return -EINVAL; 122 123 bprm->secureexec = (flags & BPF_F_BPRM_SECUREEXEC); 124 return 0; 125} 126 127BTF_ID_LIST_SINGLE(bpf_bprm_opts_set_btf_ids, struct, linux_binprm) 128 129static const struct bpf_func_proto bpf_bprm_opts_set_proto = { 130 .func = bpf_bprm_opts_set, 131 .gpl_only = false, 132 .ret_type = RET_INTEGER, 133 .arg1_type = ARG_PTR_TO_BTF_ID, 134 .arg1_btf_id = &bpf_bprm_opts_set_btf_ids[0], 135 .arg2_type = ARG_ANYTHING, 136}; 137 138BPF_CALL_3(bpf_ima_inode_hash, struct inode *, inode, void *, dst, u32, size) 139{ 140 return ima_inode_hash(inode, dst, size); 141} 142 143static bool bpf_ima_inode_hash_allowed(const struct bpf_prog *prog) 144{ 145 return bpf_lsm_is_sleepable_hook(prog->aux->attach_btf_id); 146} 147 148BTF_ID_LIST_SINGLE(bpf_ima_inode_hash_btf_ids, struct, inode) 149 150static const struct bpf_func_proto bpf_ima_inode_hash_proto = { 151 .func = bpf_ima_inode_hash, 152 .gpl_only = false, 153 .might_sleep = true, 154 .ret_type = RET_INTEGER, 155 .arg1_type = ARG_PTR_TO_BTF_ID, 156 .arg1_btf_id = &bpf_ima_inode_hash_btf_ids[0], 157 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 158 .arg3_type = ARG_CONST_SIZE, 159 .allowed = bpf_ima_inode_hash_allowed, 160}; 161 162BPF_CALL_3(bpf_ima_file_hash, struct file *, file, void *, dst, u32, size) 163{ 164 return ima_file_hash(file, dst, size); 165} 166 167BTF_ID_LIST_SINGLE(bpf_ima_file_hash_btf_ids, struct, file) 168 169static const struct bpf_func_proto bpf_ima_file_hash_proto = { 170 .func = bpf_ima_file_hash, 171 .gpl_only = false, 172 .might_sleep = true, 173 .ret_type = RET_INTEGER, 174 .arg1_type = ARG_PTR_TO_BTF_ID, 175 .arg1_btf_id = &bpf_ima_file_hash_btf_ids[0], 176 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 177 .arg3_type = ARG_CONST_SIZE, 178 .allowed = bpf_ima_inode_hash_allowed, 179}; 180 181BPF_CALL_1(bpf_get_attach_cookie, void *, ctx) 182{ 183 struct bpf_trace_run_ctx *run_ctx; 184 185 run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx); 186 return run_ctx->bpf_cookie; 187} 188 189static const struct bpf_func_proto bpf_get_attach_cookie_proto = { 190 .func = bpf_get_attach_cookie, 191 .gpl_only = false, 192 .ret_type = RET_INTEGER, 193 .arg1_type = ARG_PTR_TO_CTX, 194}; 195 196static const struct bpf_func_proto * 197bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 198{ 199 const struct bpf_func_proto *func_proto; 200 201 if (prog->expected_attach_type == BPF_LSM_CGROUP) { 202 func_proto = cgroup_common_func_proto(func_id, prog); 203 if (func_proto) 204 return func_proto; 205 } 206 207 switch (func_id) { 208 case BPF_FUNC_inode_storage_get: 209 return &bpf_inode_storage_get_proto; 210 case BPF_FUNC_inode_storage_delete: 211 return &bpf_inode_storage_delete_proto; 212#ifdef CONFIG_NET 213 case BPF_FUNC_sk_storage_get: 214 return &bpf_sk_storage_get_proto; 215 case BPF_FUNC_sk_storage_delete: 216 return &bpf_sk_storage_delete_proto; 217#endif /* CONFIG_NET */ 218 case BPF_FUNC_spin_lock: 219 return &bpf_spin_lock_proto; 220 case BPF_FUNC_spin_unlock: 221 return &bpf_spin_unlock_proto; 222 case BPF_FUNC_bprm_opts_set: 223 return &bpf_bprm_opts_set_proto; 224 case BPF_FUNC_ima_inode_hash: 225 return &bpf_ima_inode_hash_proto; 226 case BPF_FUNC_ima_file_hash: 227 return &bpf_ima_file_hash_proto; 228 case BPF_FUNC_get_attach_cookie: 229 return bpf_prog_has_trampoline(prog) ? &bpf_get_attach_cookie_proto : NULL; 230#ifdef CONFIG_NET 231 case BPF_FUNC_setsockopt: 232 if (prog->expected_attach_type != BPF_LSM_CGROUP) 233 return NULL; 234 if (btf_id_set_contains(&bpf_lsm_locked_sockopt_hooks, 235 prog->aux->attach_btf_id)) 236 return &bpf_sk_setsockopt_proto; 237 if (btf_id_set_contains(&bpf_lsm_unlocked_sockopt_hooks, 238 prog->aux->attach_btf_id)) 239 return &bpf_unlocked_sk_setsockopt_proto; 240 return NULL; 241 case BPF_FUNC_getsockopt: 242 if (prog->expected_attach_type != BPF_LSM_CGROUP) 243 return NULL; 244 if (btf_id_set_contains(&bpf_lsm_locked_sockopt_hooks, 245 prog->aux->attach_btf_id)) 246 return &bpf_sk_getsockopt_proto; 247 if (btf_id_set_contains(&bpf_lsm_unlocked_sockopt_hooks, 248 prog->aux->attach_btf_id)) 249 return &bpf_unlocked_sk_getsockopt_proto; 250 return NULL; 251#endif 252 default: 253 return tracing_prog_func_proto(func_id, prog); 254 } 255} 256 257/* The set of hooks which are called without pagefaults disabled and are allowed 258 * to "sleep" and thus can be used for sleepable BPF programs. 259 */ 260BTF_SET_START(sleepable_lsm_hooks) 261BTF_ID(func, bpf_lsm_bpf) 262BTF_ID(func, bpf_lsm_bpf_map) 263BTF_ID(func, bpf_lsm_bpf_map_create) 264BTF_ID(func, bpf_lsm_bpf_map_free) 265BTF_ID(func, bpf_lsm_bpf_prog) 266BTF_ID(func, bpf_lsm_bpf_prog_load) 267BTF_ID(func, bpf_lsm_bpf_prog_free) 268BTF_ID(func, bpf_lsm_bpf_token_create) 269BTF_ID(func, bpf_lsm_bpf_token_free) 270BTF_ID(func, bpf_lsm_bpf_token_cmd) 271BTF_ID(func, bpf_lsm_bpf_token_capable) 272BTF_ID(func, bpf_lsm_bprm_check_security) 273BTF_ID(func, bpf_lsm_bprm_committed_creds) 274BTF_ID(func, bpf_lsm_bprm_committing_creds) 275BTF_ID(func, bpf_lsm_bprm_creds_for_exec) 276BTF_ID(func, bpf_lsm_bprm_creds_from_file) 277BTF_ID(func, bpf_lsm_capget) 278BTF_ID(func, bpf_lsm_capset) 279BTF_ID(func, bpf_lsm_cred_prepare) 280BTF_ID(func, bpf_lsm_file_ioctl) 281BTF_ID(func, bpf_lsm_file_lock) 282BTF_ID(func, bpf_lsm_file_open) 283BTF_ID(func, bpf_lsm_file_receive) 284 285BTF_ID(func, bpf_lsm_inode_create) 286BTF_ID(func, bpf_lsm_inode_free_security) 287BTF_ID(func, bpf_lsm_inode_getattr) 288BTF_ID(func, bpf_lsm_inode_getxattr) 289BTF_ID(func, bpf_lsm_inode_mknod) 290BTF_ID(func, bpf_lsm_inode_need_killpriv) 291BTF_ID(func, bpf_lsm_inode_post_setxattr) 292BTF_ID(func, bpf_lsm_inode_readlink) 293BTF_ID(func, bpf_lsm_inode_rename) 294BTF_ID(func, bpf_lsm_inode_rmdir) 295BTF_ID(func, bpf_lsm_inode_setattr) 296BTF_ID(func, bpf_lsm_inode_setxattr) 297BTF_ID(func, bpf_lsm_inode_symlink) 298BTF_ID(func, bpf_lsm_inode_unlink) 299BTF_ID(func, bpf_lsm_kernel_module_request) 300BTF_ID(func, bpf_lsm_kernel_read_file) 301BTF_ID(func, bpf_lsm_kernfs_init_security) 302 303#ifdef CONFIG_SECURITY_PATH 304BTF_ID(func, bpf_lsm_path_unlink) 305BTF_ID(func, bpf_lsm_path_mkdir) 306BTF_ID(func, bpf_lsm_path_rmdir) 307BTF_ID(func, bpf_lsm_path_truncate) 308BTF_ID(func, bpf_lsm_path_symlink) 309BTF_ID(func, bpf_lsm_path_link) 310BTF_ID(func, bpf_lsm_path_rename) 311BTF_ID(func, bpf_lsm_path_chmod) 312BTF_ID(func, bpf_lsm_path_chown) 313#endif /* CONFIG_SECURITY_PATH */ 314 315#ifdef CONFIG_KEYS 316BTF_ID(func, bpf_lsm_key_free) 317#endif /* CONFIG_KEYS */ 318 319BTF_ID(func, bpf_lsm_mmap_file) 320BTF_ID(func, bpf_lsm_netlink_send) 321BTF_ID(func, bpf_lsm_path_notify) 322BTF_ID(func, bpf_lsm_release_secctx) 323BTF_ID(func, bpf_lsm_sb_alloc_security) 324BTF_ID(func, bpf_lsm_sb_eat_lsm_opts) 325BTF_ID(func, bpf_lsm_sb_kern_mount) 326BTF_ID(func, bpf_lsm_sb_mount) 327BTF_ID(func, bpf_lsm_sb_remount) 328BTF_ID(func, bpf_lsm_sb_set_mnt_opts) 329BTF_ID(func, bpf_lsm_sb_show_options) 330BTF_ID(func, bpf_lsm_sb_statfs) 331BTF_ID(func, bpf_lsm_sb_umount) 332BTF_ID(func, bpf_lsm_settime) 333 334#ifdef CONFIG_SECURITY_NETWORK 335BTF_ID(func, bpf_lsm_inet_conn_established) 336 337BTF_ID(func, bpf_lsm_socket_accept) 338BTF_ID(func, bpf_lsm_socket_bind) 339BTF_ID(func, bpf_lsm_socket_connect) 340BTF_ID(func, bpf_lsm_socket_create) 341BTF_ID(func, bpf_lsm_socket_getpeername) 342BTF_ID(func, bpf_lsm_socket_getpeersec_dgram) 343BTF_ID(func, bpf_lsm_socket_getsockname) 344BTF_ID(func, bpf_lsm_socket_getsockopt) 345BTF_ID(func, bpf_lsm_socket_listen) 346BTF_ID(func, bpf_lsm_socket_post_create) 347BTF_ID(func, bpf_lsm_socket_recvmsg) 348BTF_ID(func, bpf_lsm_socket_sendmsg) 349BTF_ID(func, bpf_lsm_socket_shutdown) 350BTF_ID(func, bpf_lsm_socket_socketpair) 351#endif /* CONFIG_SECURITY_NETWORK */ 352 353BTF_ID(func, bpf_lsm_syslog) 354BTF_ID(func, bpf_lsm_task_alloc) 355BTF_ID(func, bpf_lsm_current_getsecid_subj) 356BTF_ID(func, bpf_lsm_task_getsecid_obj) 357BTF_ID(func, bpf_lsm_task_prctl) 358BTF_ID(func, bpf_lsm_task_setscheduler) 359BTF_ID(func, bpf_lsm_task_to_inode) 360BTF_ID(func, bpf_lsm_userns_create) 361BTF_SET_END(sleepable_lsm_hooks) 362 363BTF_SET_START(untrusted_lsm_hooks) 364BTF_ID(func, bpf_lsm_bpf_map_free) 365BTF_ID(func, bpf_lsm_bpf_prog_free) 366BTF_ID(func, bpf_lsm_file_alloc_security) 367BTF_ID(func, bpf_lsm_file_free_security) 368#ifdef CONFIG_SECURITY_NETWORK 369BTF_ID(func, bpf_lsm_sk_alloc_security) 370BTF_ID(func, bpf_lsm_sk_free_security) 371#endif /* CONFIG_SECURITY_NETWORK */ 372BTF_ID(func, bpf_lsm_task_free) 373BTF_SET_END(untrusted_lsm_hooks) 374 375bool bpf_lsm_is_sleepable_hook(u32 btf_id) 376{ 377 return btf_id_set_contains(&sleepable_lsm_hooks, btf_id); 378} 379 380bool bpf_lsm_is_trusted(const struct bpf_prog *prog) 381{ 382 return !btf_id_set_contains(&untrusted_lsm_hooks, prog->aux->attach_btf_id); 383} 384 385const struct bpf_prog_ops lsm_prog_ops = { 386}; 387 388const struct bpf_verifier_ops lsm_verifier_ops = { 389 .get_func_proto = bpf_lsm_func_proto, 390 .is_valid_access = btf_ctx_access, 391}; 392