1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2019 Facebook 4 * Copyright 2020 Google LLC. 5 */ 6 7 #include <linux/rculist.h> 8 #include <linux/list.h> 9 #include <linux/hash.h> 10 #include <linux/types.h> 11 #include <linux/spinlock.h> 12 #include <linux/bpf.h> 13 #include <linux/bpf_local_storage.h> 14 #include <net/sock.h> 15 #include <uapi/linux/sock_diag.h> 16 #include <uapi/linux/btf.h> 17 #include <linux/bpf_lsm.h> 18 #include <linux/btf_ids.h> 19 #include <linux/fdtable.h> 20 #include <linux/rcupdate_trace.h> 21 22 DEFINE_BPF_STORAGE_CACHE(inode_cache); 23 24 static struct bpf_local_storage __rcu ** 25 inode_storage_ptr(void *owner) 26 { 27 struct inode *inode = owner; 28 struct bpf_storage_blob *bsb; 29 30 bsb = bpf_inode(inode); 31 if (!bsb) 32 return NULL; 33 return &bsb->storage; 34 } 35 36 static struct bpf_local_storage_data *inode_storage_lookup(struct inode *inode, 37 struct bpf_map *map, 38 bool cacheit_lockit) 39 { 40 struct bpf_local_storage *inode_storage; 41 struct bpf_local_storage_map *smap; 42 struct bpf_storage_blob *bsb; 43 44 bsb = bpf_inode(inode); 45 if (!bsb) 46 return NULL; 47 48 inode_storage = 49 rcu_dereference_check(bsb->storage, bpf_rcu_lock_held()); 50 if (!inode_storage) 51 return NULL; 52 53 smap = (struct bpf_local_storage_map *)map; 54 return bpf_local_storage_lookup(inode_storage, smap, cacheit_lockit); 55 } 56 57 void bpf_inode_storage_free(struct inode *inode) 58 { 59 struct bpf_local_storage *local_storage; 60 struct bpf_storage_blob *bsb; 61 62 bsb = bpf_inode(inode); 63 if (!bsb) 64 return; 65 66 rcu_read_lock(); 67 68 local_storage = rcu_dereference(bsb->storage); 69 if (!local_storage) { 70 rcu_read_unlock(); 71 return; 72 } 73 74 bpf_local_storage_destroy(local_storage); 75 rcu_read_unlock(); 76 } 77 78 static void *bpf_fd_inode_storage_lookup_elem(struct bpf_map *map, void *key) 79 { 80 struct bpf_local_storage_data *sdata; 81 CLASS(fd_raw, f)(*(int *)key); 82 83 if (fd_empty(f)) 84 return ERR_PTR(-EBADF); 85 86 sdata = inode_storage_lookup(file_inode(fd_file(f)), map, true); 87 return sdata ? sdata->data : NULL; 88 } 89 90 static long bpf_fd_inode_storage_update_elem(struct bpf_map *map, void *key, 91 void *value, u64 map_flags) 92 { 93 struct bpf_local_storage_data *sdata; 94 CLASS(fd_raw, f)(*(int *)key); 95 96 if (fd_empty(f)) 97 return -EBADF; 98 if (!inode_storage_ptr(file_inode(fd_file(f)))) 99 return -EBADF; 100 101 sdata = bpf_local_storage_update(file_inode(fd_file(f)), 102 (struct bpf_local_storage_map *)map, 103 value, map_flags, GFP_ATOMIC); 104 return PTR_ERR_OR_ZERO(sdata); 105 } 106 107 static int inode_storage_delete(struct inode *inode, struct bpf_map *map) 108 { 109 struct bpf_local_storage_data *sdata; 110 111 sdata = inode_storage_lookup(inode, map, false); 112 if (!sdata) 113 return -ENOENT; 114 115 bpf_selem_unlink(SELEM(sdata), false); 116 117 return 0; 118 } 119 120 static long bpf_fd_inode_storage_delete_elem(struct bpf_map *map, void *key) 121 { 122 CLASS(fd_raw, f)(*(int *)key); 123 124 if (fd_empty(f)) 125 return -EBADF; 126 return inode_storage_delete(file_inode(fd_file(f)), map); 127 } 128 129 /* *gfp_flags* is a hidden argument provided by the verifier */ 130 BPF_CALL_5(bpf_inode_storage_get, struct bpf_map *, map, struct inode *, inode, 131 void *, value, u64, flags, gfp_t, gfp_flags) 132 { 133 struct bpf_local_storage_data *sdata; 134 135 WARN_ON_ONCE(!bpf_rcu_lock_held()); 136 if (flags & ~(BPF_LOCAL_STORAGE_GET_F_CREATE)) 137 return (unsigned long)NULL; 138 139 /* explicitly check that the inode_storage_ptr is not 140 * NULL as inode_storage_lookup returns NULL in this case and 141 * bpf_local_storage_update expects the owner to have a 142 * valid storage pointer. 143 */ 144 if (!inode || !inode_storage_ptr(inode)) 145 return (unsigned long)NULL; 146 147 sdata = inode_storage_lookup(inode, map, true); 148 if (sdata) 149 return (unsigned long)sdata->data; 150 151 /* This helper must only called from where the inode is guaranteed 152 * to have a refcount and cannot be freed. 153 */ 154 if (flags & BPF_LOCAL_STORAGE_GET_F_CREATE) { 155 sdata = bpf_local_storage_update( 156 inode, (struct bpf_local_storage_map *)map, value, 157 BPF_NOEXIST, gfp_flags); 158 return IS_ERR(sdata) ? (unsigned long)NULL : 159 (unsigned long)sdata->data; 160 } 161 162 return (unsigned long)NULL; 163 } 164 165 BPF_CALL_2(bpf_inode_storage_delete, 166 struct bpf_map *, map, struct inode *, inode) 167 { 168 WARN_ON_ONCE(!bpf_rcu_lock_held()); 169 if (!inode) 170 return -EINVAL; 171 172 /* This helper must only called from where the inode is guaranteed 173 * to have a refcount and cannot be freed. 174 */ 175 return inode_storage_delete(inode, map); 176 } 177 178 static int notsupp_get_next_key(struct bpf_map *map, void *key, 179 void *next_key) 180 { 181 return -ENOTSUPP; 182 } 183 184 static struct bpf_map *inode_storage_map_alloc(union bpf_attr *attr) 185 { 186 return bpf_local_storage_map_alloc(attr, &inode_cache, false); 187 } 188 189 static void inode_storage_map_free(struct bpf_map *map) 190 { 191 bpf_local_storage_map_free(map, &inode_cache, NULL); 192 } 193 194 const struct bpf_map_ops inode_storage_map_ops = { 195 .map_meta_equal = bpf_map_meta_equal, 196 .map_alloc_check = bpf_local_storage_map_alloc_check, 197 .map_alloc = inode_storage_map_alloc, 198 .map_free = inode_storage_map_free, 199 .map_get_next_key = notsupp_get_next_key, 200 .map_lookup_elem = bpf_fd_inode_storage_lookup_elem, 201 .map_update_elem = bpf_fd_inode_storage_update_elem, 202 .map_delete_elem = bpf_fd_inode_storage_delete_elem, 203 .map_check_btf = bpf_local_storage_map_check_btf, 204 .map_mem_usage = bpf_local_storage_map_mem_usage, 205 .map_btf_id = &bpf_local_storage_map_btf_id[0], 206 .map_owner_storage_ptr = inode_storage_ptr, 207 }; 208 209 BTF_ID_LIST_SINGLE(bpf_inode_storage_btf_ids, struct, inode) 210 211 const struct bpf_func_proto bpf_inode_storage_get_proto = { 212 .func = bpf_inode_storage_get, 213 .gpl_only = false, 214 .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL, 215 .arg1_type = ARG_CONST_MAP_PTR, 216 .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL, 217 .arg2_btf_id = &bpf_inode_storage_btf_ids[0], 218 .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL, 219 .arg4_type = ARG_ANYTHING, 220 }; 221 222 const struct bpf_func_proto bpf_inode_storage_delete_proto = { 223 .func = bpf_inode_storage_delete, 224 .gpl_only = false, 225 .ret_type = RET_INTEGER, 226 .arg1_type = ARG_CONST_MAP_PTR, 227 .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL, 228 .arg2_btf_id = &bpf_inode_storage_btf_ids[0], 229 }; 230