1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (c) 2019 Facebook
4 * Copyright 2020 Google LLC.
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>
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>
22 DEFINE_BPF_STORAGE_CACHE(inode_cache);
24 static struct bpf_local_storage __rcu **
25 inode_storage_ptr(void *owner)
27 struct inode *inode = owner;
28 struct bpf_storage_blob *bsb;
30 bsb = bpf_inode(inode);
36 static struct bpf_local_storage_data *inode_storage_lookup(struct inode *inode,
40 struct bpf_local_storage *inode_storage;
41 struct bpf_local_storage_map *smap;
42 struct bpf_storage_blob *bsb;
44 bsb = bpf_inode(inode);
49 rcu_dereference_check(bsb->storage, bpf_rcu_lock_held());
53 smap = (struct bpf_local_storage_map *)map;
54 return bpf_local_storage_lookup(inode_storage, smap, cacheit_lockit);
57 void bpf_inode_storage_free(struct inode *inode)
59 struct bpf_local_storage_elem *selem;
60 struct bpf_local_storage *local_storage;
61 bool free_inode_storage = false;
62 struct bpf_storage_blob *bsb;
65 bsb = bpf_inode(inode);
71 local_storage = rcu_dereference(bsb->storage);
77 /* Neither the bpf_prog nor the bpf-map's syscall
78 * could be modifying the local_storage->list now.
79 * Thus, no elem can be added-to or deleted-from the
80 * local_storage->list by the bpf_prog or by the bpf-map's syscall.
82 * It is racing with bpf_local_storage_map_free() alone
83 * when unlinking elem from the local_storage->list and
84 * the map's bucket->list.
86 raw_spin_lock_bh(&local_storage->lock);
87 hlist_for_each_entry_safe(selem, n, &local_storage->list, snode) {
88 /* Always unlink from map before unlinking from
91 bpf_selem_unlink_map(selem);
92 free_inode_storage = bpf_selem_unlink_storage_nolock(
93 local_storage, selem, false);
95 raw_spin_unlock_bh(&local_storage->lock);
98 /* free_inoode_storage should always be true as long as
99 * local_storage->list was non-empty.
101 if (free_inode_storage)
102 kfree_rcu(local_storage, rcu);
105 static void *bpf_fd_inode_storage_lookup_elem(struct bpf_map *map, void *key)
107 struct bpf_local_storage_data *sdata;
114 return ERR_PTR(-EBADF);
116 sdata = inode_storage_lookup(f->f_inode, map, true);
118 return sdata ? sdata->data : NULL;
121 static int bpf_fd_inode_storage_update_elem(struct bpf_map *map, void *key,
122 void *value, u64 map_flags)
124 struct bpf_local_storage_data *sdata;
132 if (!inode_storage_ptr(f->f_inode)) {
137 sdata = bpf_local_storage_update(f->f_inode,
138 (struct bpf_local_storage_map *)map,
141 return PTR_ERR_OR_ZERO(sdata);
144 static int inode_storage_delete(struct inode *inode, struct bpf_map *map)
146 struct bpf_local_storage_data *sdata;
148 sdata = inode_storage_lookup(inode, map, false);
152 bpf_selem_unlink(SELEM(sdata));
157 static int bpf_fd_inode_storage_delete_elem(struct bpf_map *map, void *key)
167 err = inode_storage_delete(f->f_inode, map);
172 BPF_CALL_4(bpf_inode_storage_get, struct bpf_map *, map, struct inode *, inode,
173 void *, value, u64, flags)
175 struct bpf_local_storage_data *sdata;
177 WARN_ON_ONCE(!bpf_rcu_lock_held());
178 if (flags & ~(BPF_LOCAL_STORAGE_GET_F_CREATE))
179 return (unsigned long)NULL;
181 /* explicitly check that the inode_storage_ptr is not
182 * NULL as inode_storage_lookup returns NULL in this case and
183 * bpf_local_storage_update expects the owner to have a
184 * valid storage pointer.
186 if (!inode || !inode_storage_ptr(inode))
187 return (unsigned long)NULL;
189 sdata = inode_storage_lookup(inode, map, true);
191 return (unsigned long)sdata->data;
193 /* This helper must only called from where the inode is guaranteed
194 * to have a refcount and cannot be freed.
196 if (flags & BPF_LOCAL_STORAGE_GET_F_CREATE) {
197 sdata = bpf_local_storage_update(
198 inode, (struct bpf_local_storage_map *)map, value,
200 return IS_ERR(sdata) ? (unsigned long)NULL :
201 (unsigned long)sdata->data;
204 return (unsigned long)NULL;
207 BPF_CALL_2(bpf_inode_storage_delete,
208 struct bpf_map *, map, struct inode *, inode)
210 WARN_ON_ONCE(!bpf_rcu_lock_held());
214 /* This helper must only called from where the inode is guaranteed
215 * to have a refcount and cannot be freed.
217 return inode_storage_delete(inode, map);
220 static int notsupp_get_next_key(struct bpf_map *map, void *key,
226 static struct bpf_map *inode_storage_map_alloc(union bpf_attr *attr)
228 struct bpf_local_storage_map *smap;
230 smap = bpf_local_storage_map_alloc(attr);
232 return ERR_CAST(smap);
234 smap->cache_idx = bpf_local_storage_cache_idx_get(&inode_cache);
238 static void inode_storage_map_free(struct bpf_map *map)
240 struct bpf_local_storage_map *smap;
242 smap = (struct bpf_local_storage_map *)map;
243 bpf_local_storage_cache_idx_free(&inode_cache, smap->cache_idx);
244 bpf_local_storage_map_free(smap, NULL);
247 static int inode_storage_map_btf_id;
248 const struct bpf_map_ops inode_storage_map_ops = {
249 .map_meta_equal = bpf_map_meta_equal,
250 .map_alloc_check = bpf_local_storage_map_alloc_check,
251 .map_alloc = inode_storage_map_alloc,
252 .map_free = inode_storage_map_free,
253 .map_get_next_key = notsupp_get_next_key,
254 .map_lookup_elem = bpf_fd_inode_storage_lookup_elem,
255 .map_update_elem = bpf_fd_inode_storage_update_elem,
256 .map_delete_elem = bpf_fd_inode_storage_delete_elem,
257 .map_check_btf = bpf_local_storage_map_check_btf,
258 .map_btf_name = "bpf_local_storage_map",
259 .map_btf_id = &inode_storage_map_btf_id,
260 .map_owner_storage_ptr = inode_storage_ptr,
263 BTF_ID_LIST_SINGLE(bpf_inode_storage_btf_ids, struct, inode)
265 const struct bpf_func_proto bpf_inode_storage_get_proto = {
266 .func = bpf_inode_storage_get,
268 .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
269 .arg1_type = ARG_CONST_MAP_PTR,
270 .arg2_type = ARG_PTR_TO_BTF_ID,
271 .arg2_btf_id = &bpf_inode_storage_btf_ids[0],
272 .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL,
273 .arg4_type = ARG_ANYTHING,
276 const struct bpf_func_proto bpf_inode_storage_delete_proto = {
277 .func = bpf_inode_storage_delete,
279 .ret_type = RET_INTEGER,
280 .arg1_type = ARG_CONST_MAP_PTR,
281 .arg2_type = ARG_PTR_TO_BTF_ID,
282 .arg2_btf_id = &bpf_inode_storage_btf_ids[0],