netfilter: nftables: avoid potential overflows on 32bit arches

User space could ask for very large hash tables, we need to make sure
our size computations wont overflow.

nf_tables_newset() needs to double check the u64 size
will fit into size_t field.

Fixes: 0ed6389c483d ("netfilter: nf_tables: rename set implementations")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 926da6e..d63d2d8 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -4184,6 +4184,7 @@ static int nf_tables_newset(struct sk_buff *skb, const struct nfnl_info *info,
        unsigned char *udata;
        struct nft_set *set;
        struct nft_ctx ctx;
+       size_t alloc_size;
        u64 timeout;
        char *name;
        int err, i;
@@ -4329,8 +4330,10 @@ static int nf_tables_newset(struct sk_buff *skb, const struct nfnl_info *info,
        size = 0;
        if (ops->privsize != NULL)
                size = ops->privsize(nla, &desc);
-
-       set = kvzalloc(sizeof(*set) + size + udlen, GFP_KERNEL);
+       alloc_size = sizeof(*set) + size + udlen;
+       if (alloc_size < size)
+               return -ENOMEM;
+       set = kvzalloc(alloc_size, GFP_KERNEL);
        if (!set)
                return -ENOMEM;
 

diff --git a/net/netfilter/nft_set_hash.c b/net/netfilter/nft_set_hash.c
index 328f2ce..7b3d0a7 100644 (file)
--- a/net/netfilter/nft_set_hash.c
+++ b/net/netfilter/nft_set_hash.c
@@ -623,7 +623,7 @@ static u64 nft_hash_privsize(const struct nlattr * const nla[],
                             const struct nft_set_desc *desc)
 {
        return sizeof(struct nft_hash) +
-              nft_hash_buckets(desc->size) * sizeof(struct hlist_head);
+              (u64)nft_hash_buckets(desc->size) * sizeof(struct hlist_head);
 }
 
 static int nft_hash_init(const struct nft_set *set,
@@ -663,8 +663,8 @@ static bool nft_hash_estimate(const struct nft_set_desc *desc, u32 features,
                return false;
 
        est->size   = sizeof(struct nft_hash) +
-                     nft_hash_buckets(desc->size) * sizeof(struct hlist_head) +
-                     desc->size * sizeof(struct nft_hash_elem);
+                     (u64)nft_hash_buckets(desc->size) * sizeof(struct hlist_head) +
+                     (u64)desc->size * sizeof(struct nft_hash_elem);
        est->lookup = NFT_SET_CLASS_O_1;
        est->space  = NFT_SET_CLASS_O_N;
 
@@ -681,8 +681,8 @@ static bool nft_hash_fast_estimate(const struct nft_set_desc *desc, u32 features
                return false;
 
        est->size   = sizeof(struct nft_hash) +
-                     nft_hash_buckets(desc->size) * sizeof(struct hlist_head) +
-                     desc->size * sizeof(struct nft_hash_elem);
+                     (u64)nft_hash_buckets(desc->size) * sizeof(struct hlist_head) +
+                     (u64)desc->size * sizeof(struct nft_hash_elem);
        est->lookup = NFT_SET_CLASS_O_1;
        est->space  = NFT_SET_CLASS_O_N;