diff options
| author | Eric Dumazet <edumazet@google.com> | 2021-05-06 05:53:23 -0700 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2021-05-07 10:01:29 +0200 |
| commit | a54754ec9891830ba548e2010c889e3c8146e449 (patch) | |
| tree | 5806f69223da2a63bf2461b97985be43b3b23bc8 /net | |
| parent | 85dfd816fabfc16e71786eda0a33a7046688b5b0 (diff) | |
netfilter: nftables: avoid overflows in nft_hash_buckets()
Number of buckets being stored in 32bit variables, we have to
ensure that no overflows occur in nft_hash_buckets()
syzbot injected a size == 0x40000000 and reported:
UBSAN: shift-out-of-bounds in ./include/linux/log2.h:57:13
shift exponent 64 is too large for 64-bit type 'long unsigned int'
CPU: 1 PID: 29539 Comm: syz-executor.4 Not tainted 5.12.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x141/0x1d7 lib/dump_stack.c:120
ubsan_epilogue+0xb/0x5a lib/ubsan.c:148
__ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:327
__roundup_pow_of_two include/linux/log2.h:57 [inline]
nft_hash_buckets net/netfilter/nft_set_hash.c:411 [inline]
nft_hash_estimate.cold+0x19/0x1e net/netfilter/nft_set_hash.c:652
nft_select_set_ops net/netfilter/nf_tables_api.c:3586 [inline]
nf_tables_newset+0xe62/0x3110 net/netfilter/nf_tables_api.c:4322
nfnetlink_rcv_batch+0xa09/0x24b0 net/netfilter/nfnetlink.c:488
nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:612 [inline]
nfnetlink_rcv+0x3af/0x420 net/netfilter/nfnetlink.c:630
netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1338
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1927
sock_sendmsg_nosec net/socket.c:654 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:674
____sys_sendmsg+0x6e8/0x810 net/socket.c:2350
___sys_sendmsg+0xf3/0x170 net/socket.c:2404
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2433
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
Fixes: 0ed6389c483d ("netfilter: nf_tables: rename set implementations")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/netfilter/nft_set_hash.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/net/netfilter/nft_set_hash.c b/net/netfilter/nft_set_hash.c index 58f576abcd4a..328f2ce32e4c 100644 --- a/net/netfilter/nft_set_hash.c +++ b/net/netfilter/nft_set_hash.c @@ -412,9 +412,17 @@ static void nft_rhash_destroy(const struct nft_set *set) (void *)set); } +/* Number of buckets is stored in u32, so cap our result to 1U<<31 */ +#define NFT_MAX_BUCKETS (1U << 31) + static u32 nft_hash_buckets(u32 size) { - return roundup_pow_of_two(size * 4 / 3); + u64 val = div_u64((u64)size * 4, 3); + + if (val >= NFT_MAX_BUCKETS) + return NFT_MAX_BUCKETS; + + return roundup_pow_of_two(val); } static bool nft_rhash_estimate(const struct nft_set_desc *desc, u32 features, |