netfilter: ipset: Fix sparse warnings due to missing rcu annotations

Reported-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>

diff --git a/net/netfilter/ipset/ip_set_hash_gen.h b/net/netfilter/ipset/ip_set_hash_gen.h
index 7ff20ecbe185ce192137b198fad9bad1ff3aed5a..09a21dd5f12022b5be7f59a06a7cae5fcbd8258f 100644 (file)
--- a/net/netfilter/ipset/ip_set_hash_gen.h
+++ b/net/netfilter/ipset/ip_set_hash_gen.h
@@ -15,6 +15,8 @@
 #define rcu_dereference_bh(p)  rcu_dereference(p)
 #endif
 
+#define rcu_dereference_bh_nfnl(p)     rcu_dereference_bh_check(p, 1)
+
 #define CONCAT(a, b)           a##b
 #define TOKEN(a, b)            CONCAT(a, b)
 
@@ -269,7 +271,7 @@ hbucket_elem_add(struct hbucket *n, u8 ahash_max, size_t dsize)
 
 /* The generic hash structure */
 struct htype {
-       struct htable *table;   /* the hash table */
+       struct htable __rcu *table; /* the hash table */
        u32 maxelem;            /* max elements in the hash */
        u32 elements;           /* current element (vs timeout) */
        u32 initval;            /* random jhash init value */
@@ -347,10 +349,10 @@ mtype_del_cidr(struct htype *h, u8 cidr, u8 nets_length)
 
 /* Calculate the actual memory size of the set data */
 static size_t
-mtype_ahash_memsize(const struct htype *h, u8 nets_length)
+mtype_ahash_memsize(const struct htype *h, const struct htable *t,
+                   u8 nets_length)
 {
        u32 i;
-       struct htable *t = h->table;
        size_t memsize = sizeof(*h)
                         + sizeof(*t)
 #ifdef IP_SET_HASH_WITH_NETS
@@ -369,10 +371,11 @@ static void
 mtype_flush(struct ip_set *set)
 {
        struct htype *h = set->data;
-       struct htable *t = h->table;
+       struct htable *t;
        struct hbucket *n;
        u32 i;
 
+       t = rcu_dereference_bh_nfnl(h->table);
        for (i = 0; i < jhash_size(t->htable_bits); i++) {
                n = hbucket(t, i);
                if (n->size) {
@@ -397,7 +400,7 @@ mtype_destroy(struct ip_set *set)
        if (set->extensions & IPSET_EXT_TIMEOUT)
                del_timer_sync(&h->gc);
 
-       ahash_destroy(h->table);
+       ahash_destroy(rcu_dereference_bh_nfnl(h->table));
 #ifdef IP_SET_HASH_WITH_RBTREE
        rbtree_destroy(&h->rbtree);
 #endif
@@ -443,12 +446,14 @@ mtype_same_set(const struct ip_set *a, const struct ip_set *b)
 static void
 mtype_expire(struct htype *h, u8 nets_length, size_t dsize)
 {
-       struct htable *t = h->table;
+       struct htable *t;
        struct hbucket *n;
        struct mtype_elem *data;
        u32 i;
        int j;
 
+       rcu_read_lock_bh();
+       t = rcu_dereference_bh(h->table);
        for (i = 0; i < jhash_size(t->htable_bits); i++) {
                n = hbucket(t, i);
                for (j = 0; j < n->pos; j++) {
@@ -481,6 +486,7 @@ mtype_expire(struct htype *h, u8 nets_length, size_t dsize)
                        n->value = tmp;
                }
        }
+       rcu_read_unlock_bh();
 }
 
 static void
@@ -505,7 +511,7 @@ static int
 mtype_resize(struct ip_set *set, bool retried)
 {
        struct htype *h = set->data;
-       struct htable *t, *orig = h->table;
+       struct htable *t, *orig = rcu_dereference_bh_nfnl(h->table);
        u8 htable_bits = orig->htable_bits;
 #ifdef IP_SET_HASH_WITH_NETS
        u8 flags;
@@ -682,13 +688,15 @@ mtype_del(struct ip_set *set, void *value, const struct ip_set_ext *ext,
          struct ip_set_ext *mext, u32 flags)
 {
        struct htype *h = set->data;
-       struct htable *t = h->table;
+       struct htable *t;
        const struct mtype_elem *d = value;
        struct mtype_elem *data;
        struct hbucket *n;
-       int i;
+       int i, ret = -IPSET_ERR_EXIST;
        u32 key, multi = 0;
 
+       rcu_read_lock_bh();
+       t = rcu_dereference_bh(h->table);
        key = HKEY(value, h->initval, t->htable_bits);
        n = hbucket(t, key);
        for (i = 0; i < n->pos; i++) {
@@ -697,7 +705,7 @@ mtype_del(struct ip_set *set, void *value, const struct ip_set_ext *ext,
                        continue;
                if (SET_WITH_TIMEOUT(set) &&
                    ip_set_timeout_expired(ext_timeout(data, h)))
-                       return -IPSET_ERR_EXIST;
+                       goto out;
                if (i != n->pos - 1)
                        /* Not last one */
                        memcpy(data, ahash_data(n, n->pos - 1, h->dsize),
@@ -712,17 +720,22 @@ mtype_del(struct ip_set *set, void *value, const struct ip_set_ext *ext,
                        void *tmp = kzalloc((n->size - AHASH_INIT_SIZE)
                                            * h->dsize,
                                            GFP_ATOMIC);
-                       if (!tmp)
-                               return 0;
+                       if (!tmp) {
+                               ret = 0;
+                               goto out;
+                       }
                        n->size -= AHASH_INIT_SIZE;
                        memcpy(tmp, n->value, n->size * h->dsize);
                        kfree(n->value);
                        n->value = tmp;
                }
-               return 0;
+               ret = 0;
+               goto out;
        }
 
-       return -IPSET_ERR_EXIST;
+out:
+       rcu_read_unlock_bh();
+       return ret;
 }
 
 static inline int
@@ -745,7 +758,7 @@ mtype_test_cidrs(struct ip_set *set, struct mtype_elem *d,
                 struct ip_set_ext *mext, u32 flags)
 {
        struct htype *h = set->data;
-       struct htable *t = h->table;
+       struct htable *t = rcu_dereference_bh(h->table);
        struct hbucket *n;
        struct mtype_elem *data;
        int i, j = 0;
@@ -785,18 +798,22 @@ mtype_test(struct ip_set *set, void *value, const struct ip_set_ext *ext,
           struct ip_set_ext *mext, u32 flags)
 {
        struct htype *h = set->data;
-       struct htable *t = h->table;
+       struct htable *t;
        struct mtype_elem *d = value;
        struct hbucket *n;
        struct mtype_elem *data;
-       int i;
+       int i, ret = 0;
        u32 key, multi = 0;
 
+       rcu_read_lock_bh();
+       t = rcu_dereference_bh(h->table);
 #ifdef IP_SET_HASH_WITH_NETS
        /* If we test an IP address and not a network address,
         * try all possible network sizes */
-       if (CIDR(d->cidr) == SET_HOST_MASK(set->family))
-               return mtype_test_cidrs(set, d, ext, mext, flags);
+       if (CIDR(d->cidr) == SET_HOST_MASK(set->family)) {
+               ret = mtype_test_cidrs(set, d, ext, mext, flags);
+               goto out;
+       }
 #endif
 
        key = HKEY(d, h->initval, t->htable_bits);
@@ -805,10 +822,14 @@ mtype_test(struct ip_set *set, void *value, const struct ip_set_ext *ext,
                data = ahash_data(n, i, h->dsize);
                if (mtype_data_equal(data, d, &multi) &&
                    !(SET_WITH_TIMEOUT(set) &&
-                     ip_set_timeout_expired(ext_timeout(data, h))))
-                       return mtype_data_match(data, ext, mext, set, flags);
+                     ip_set_timeout_expired(ext_timeout(data, h)))) {
+                       ret = mtype_data_match(data, ext, mext, set, flags);
+                       goto out;
+               }
        }
-       return 0;
+out:
+       rcu_read_unlock_bh();
+       return ret;
 }
 
 /* Reply a HEADER request: fill out the header part of the set */
@@ -816,18 +837,18 @@ static int
 mtype_head(struct ip_set *set, struct sk_buff *skb)
 {
        const struct htype *h = set->data;
+       const struct htable *t;
        struct nlattr *nested;
        size_t memsize;
 
-       read_lock_bh(&set->lock);
-       memsize = mtype_ahash_memsize(h, NETS_LENGTH(set->family));
-       read_unlock_bh(&set->lock);
+       t = rcu_dereference_bh_nfnl(h->table);
+       memsize = mtype_ahash_memsize(h, t, NETS_LENGTH(set->family));
 
        nested = ipset_nest_start(skb, IPSET_ATTR_DATA);
        if (!nested)
                goto nla_put_failure;
        if (nla_put_net32(skb, IPSET_ATTR_HASHSIZE,
-                         htonl(jhash_size(h->table->htable_bits))) ||
+                         htonl(jhash_size(t->htable_bits))) ||
            nla_put_net32(skb, IPSET_ATTR_MAXELEM, htonl(h->maxelem)))
                goto nla_put_failure;
 #ifdef IP_SET_HASH_WITH_NETMASK
@@ -856,7 +877,7 @@ mtype_list(const struct ip_set *set,
           struct sk_buff *skb, struct netlink_callback *cb)
 {
        const struct htype *h = set->data;
-       const struct htable *t = h->table;
+       const struct htable *t = rcu_dereference_bh_nfnl(h->table);
        struct nlattr *atd, *nested;
        const struct hbucket *n;
        const struct mtype_elem *e;
@@ -956,6 +977,7 @@ TOKEN(HTYPE, _create)(struct ip_set *set, struct nlattr *tb[], u32 flags)
 #endif
        size_t hsize;
        struct HTYPE *h;
+       struct htable *t;
 
        if (!(set->family == NFPROTO_IPV4 || set->family == NFPROTO_IPV6))
                return -IPSET_ERR_INVALID_FAMILY;
@@ -1013,12 +1035,13 @@ TOKEN(HTYPE, _create)(struct ip_set *set, struct nlattr *tb[], u32 flags)
                kfree(h);
                return -ENOMEM;
        }
-       h->table = ip_set_alloc(hsize);
-       if (!h->table) {
+       t = ip_set_alloc(hsize);
+       if (!t) {
                kfree(h);
                return -ENOMEM;
        }
-       h->table->htable_bits = hbits;
+       t->htable_bits = hbits;
+       rcu_assign_pointer(h->table, t);
 
        set->data = h;
        if (set->family ==  NFPROTO_IPV4)
@@ -1096,8 +1119,8 @@ TOKEN(HTYPE, _create)(struct ip_set *set, struct nlattr *tb[], u32 flags)
        }
 
        pr_debug("create %s hashsize %u (%u) maxelem %u: %p(%p)\n",
-                set->name, jhash_size(h->table->htable_bits),
-                h->table->htable_bits, h->maxelem, set->data, h->table);
+                set->name, jhash_size(t->htable_bits),
+                t->htable_bits, h->maxelem, set->data, t);
 
        return 0;
 }