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 20 /* For every LSM hook that allows attachment of BPF programs, declare a nop 21 * function where a BPF program can be attached. 22 */ 23 #define LSM_HOOK(RET, DEFAULT, NAME, ...) \ 24 noinline RET bpf_lsm_##NAME(__VA_ARGS__) \ 25 { \ 26 return DEFAULT; \ 27 } 28 29 #include <linux/lsm_hook_defs.h> 30 #undef LSM_HOOK 31 32 #define LSM_HOOK(RET, DEFAULT, NAME, ...) BTF_ID(func, bpf_lsm_##NAME) 33 BTF_SET_START(bpf_lsm_hooks) 34 #include <linux/lsm_hook_defs.h> 35 #undef LSM_HOOK 36 BTF_SET_END(bpf_lsm_hooks) 37 38 int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog, 39 const struct bpf_prog *prog) 40 { 41 if (!prog->gpl_compatible) { 42 bpf_log(vlog, 43 "LSM programs must have a GPL compatible license\n"); 44 return -EINVAL; 45 } 46 47 if (!btf_id_set_contains(&bpf_lsm_hooks, prog->aux->attach_btf_id)) { 48 bpf_log(vlog, "attach_btf_id %u points to wrong type name %s\n", 49 prog->aux->attach_btf_id, prog->aux->attach_func_name); 50 return -EINVAL; 51 } 52 53 return 0; 54 } 55 56 /* Mask for all the currently supported BPRM option flags */ 57 #define BPF_F_BRPM_OPTS_MASK BPF_F_BPRM_SECUREEXEC 58 59 BPF_CALL_2(bpf_bprm_opts_set, struct linux_binprm *, bprm, u64, flags) 60 { 61 if (flags & ~BPF_F_BRPM_OPTS_MASK) 62 return -EINVAL; 63 64 bprm->secureexec = (flags & BPF_F_BPRM_SECUREEXEC); 65 return 0; 66 } 67 68 BTF_ID_LIST_SINGLE(bpf_bprm_opts_set_btf_ids, struct, linux_binprm) 69 70 const static struct bpf_func_proto bpf_bprm_opts_set_proto = { 71 .func = bpf_bprm_opts_set, 72 .gpl_only = false, 73 .ret_type = RET_INTEGER, 74 .arg1_type = ARG_PTR_TO_BTF_ID, 75 .arg1_btf_id = &bpf_bprm_opts_set_btf_ids[0], 76 .arg2_type = ARG_ANYTHING, 77 }; 78 79 BPF_CALL_3(bpf_ima_inode_hash, struct inode *, inode, void *, dst, u32, size) 80 { 81 return ima_inode_hash(inode, dst, size); 82 } 83 84 static bool bpf_ima_inode_hash_allowed(const struct bpf_prog *prog) 85 { 86 return bpf_lsm_is_sleepable_hook(prog->aux->attach_btf_id); 87 } 88 89 BTF_ID_LIST_SINGLE(bpf_ima_inode_hash_btf_ids, struct, inode) 90 91 const static struct bpf_func_proto bpf_ima_inode_hash_proto = { 92 .func = bpf_ima_inode_hash, 93 .gpl_only = false, 94 .ret_type = RET_INTEGER, 95 .arg1_type = ARG_PTR_TO_BTF_ID, 96 .arg1_btf_id = &bpf_ima_inode_hash_btf_ids[0], 97 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 98 .arg3_type = ARG_CONST_SIZE, 99 .allowed = bpf_ima_inode_hash_allowed, 100 }; 101 102 static const struct bpf_func_proto * 103 bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 104 { 105 switch (func_id) { 106 case BPF_FUNC_inode_storage_get: 107 return &bpf_inode_storage_get_proto; 108 case BPF_FUNC_inode_storage_delete: 109 return &bpf_inode_storage_delete_proto; 110 case BPF_FUNC_sk_storage_get: 111 return &bpf_sk_storage_get_proto; 112 case BPF_FUNC_sk_storage_delete: 113 return &bpf_sk_storage_delete_proto; 114 case BPF_FUNC_spin_lock: 115 return &bpf_spin_lock_proto; 116 case BPF_FUNC_spin_unlock: 117 return &bpf_spin_unlock_proto; 118 case BPF_FUNC_task_storage_get: 119 return &bpf_task_storage_get_proto; 120 case BPF_FUNC_task_storage_delete: 121 return &bpf_task_storage_delete_proto; 122 case BPF_FUNC_bprm_opts_set: 123 return &bpf_bprm_opts_set_proto; 124 case BPF_FUNC_ima_inode_hash: 125 return prog->aux->sleepable ? &bpf_ima_inode_hash_proto : NULL; 126 default: 127 return tracing_prog_func_proto(func_id, prog); 128 } 129 } 130 131 /* The set of hooks which are called without pagefaults disabled and are allowed 132 * to "sleep" and thus can be used for sleeable BPF programs. 133 */ 134 BTF_SET_START(sleepable_lsm_hooks) 135 BTF_ID(func, bpf_lsm_bpf) 136 BTF_ID(func, bpf_lsm_bpf_map) 137 BTF_ID(func, bpf_lsm_bpf_map_alloc_security) 138 BTF_ID(func, bpf_lsm_bpf_map_free_security) 139 BTF_ID(func, bpf_lsm_bpf_prog) 140 BTF_ID(func, bpf_lsm_bprm_check_security) 141 BTF_ID(func, bpf_lsm_bprm_committed_creds) 142 BTF_ID(func, bpf_lsm_bprm_committing_creds) 143 BTF_ID(func, bpf_lsm_bprm_creds_for_exec) 144 BTF_ID(func, bpf_lsm_bprm_creds_from_file) 145 BTF_ID(func, bpf_lsm_capget) 146 BTF_ID(func, bpf_lsm_capset) 147 BTF_ID(func, bpf_lsm_cred_prepare) 148 BTF_ID(func, bpf_lsm_file_ioctl) 149 BTF_ID(func, bpf_lsm_file_lock) 150 BTF_ID(func, bpf_lsm_file_open) 151 BTF_ID(func, bpf_lsm_file_receive) 152 BTF_ID(func, bpf_lsm_inet_conn_established) 153 BTF_ID(func, bpf_lsm_inode_create) 154 BTF_ID(func, bpf_lsm_inode_free_security) 155 BTF_ID(func, bpf_lsm_inode_getattr) 156 BTF_ID(func, bpf_lsm_inode_getxattr) 157 BTF_ID(func, bpf_lsm_inode_mknod) 158 BTF_ID(func, bpf_lsm_inode_need_killpriv) 159 BTF_ID(func, bpf_lsm_inode_post_setxattr) 160 BTF_ID(func, bpf_lsm_inode_readlink) 161 BTF_ID(func, bpf_lsm_inode_rename) 162 BTF_ID(func, bpf_lsm_inode_rmdir) 163 BTF_ID(func, bpf_lsm_inode_setattr) 164 BTF_ID(func, bpf_lsm_inode_setxattr) 165 BTF_ID(func, bpf_lsm_inode_symlink) 166 BTF_ID(func, bpf_lsm_inode_unlink) 167 BTF_ID(func, bpf_lsm_kernel_module_request) 168 BTF_ID(func, bpf_lsm_kernfs_init_security) 169 BTF_ID(func, bpf_lsm_key_free) 170 BTF_ID(func, bpf_lsm_mmap_file) 171 BTF_ID(func, bpf_lsm_netlink_send) 172 BTF_ID(func, bpf_lsm_path_notify) 173 BTF_ID(func, bpf_lsm_release_secctx) 174 BTF_ID(func, bpf_lsm_sb_alloc_security) 175 BTF_ID(func, bpf_lsm_sb_eat_lsm_opts) 176 BTF_ID(func, bpf_lsm_sb_kern_mount) 177 BTF_ID(func, bpf_lsm_sb_mount) 178 BTF_ID(func, bpf_lsm_sb_remount) 179 BTF_ID(func, bpf_lsm_sb_set_mnt_opts) 180 BTF_ID(func, bpf_lsm_sb_show_options) 181 BTF_ID(func, bpf_lsm_sb_statfs) 182 BTF_ID(func, bpf_lsm_sb_umount) 183 BTF_ID(func, bpf_lsm_settime) 184 BTF_ID(func, bpf_lsm_socket_accept) 185 BTF_ID(func, bpf_lsm_socket_bind) 186 BTF_ID(func, bpf_lsm_socket_connect) 187 BTF_ID(func, bpf_lsm_socket_create) 188 BTF_ID(func, bpf_lsm_socket_getpeername) 189 BTF_ID(func, bpf_lsm_socket_getpeersec_dgram) 190 BTF_ID(func, bpf_lsm_socket_getsockname) 191 BTF_ID(func, bpf_lsm_socket_getsockopt) 192 BTF_ID(func, bpf_lsm_socket_listen) 193 BTF_ID(func, bpf_lsm_socket_post_create) 194 BTF_ID(func, bpf_lsm_socket_recvmsg) 195 BTF_ID(func, bpf_lsm_socket_sendmsg) 196 BTF_ID(func, bpf_lsm_socket_shutdown) 197 BTF_ID(func, bpf_lsm_socket_socketpair) 198 BTF_ID(func, bpf_lsm_syslog) 199 BTF_ID(func, bpf_lsm_task_alloc) 200 BTF_ID(func, bpf_lsm_task_getsecid) 201 BTF_ID(func, bpf_lsm_task_prctl) 202 BTF_ID(func, bpf_lsm_task_setscheduler) 203 BTF_ID(func, bpf_lsm_task_to_inode) 204 BTF_SET_END(sleepable_lsm_hooks) 205 206 bool bpf_lsm_is_sleepable_hook(u32 btf_id) 207 { 208 return btf_id_set_contains(&sleepable_lsm_hooks, btf_id); 209 } 210 211 const struct bpf_prog_ops lsm_prog_ops = { 212 }; 213 214 const struct bpf_verifier_ops lsm_verifier_ops = { 215 .get_func_proto = bpf_lsm_func_proto, 216 .is_valid_access = btf_ctx_access, 217 }; 218