| From b895bdf5d643b6feb7c60856326dd4feb6981560 Mon Sep 17 00:00:00 2001 |
| From: Eric Dumazet <edumazet@google.com> |
| Date: Fri, 9 Apr 2021 08:49:39 -0700 |
| Subject: netfilter: nft_limit: avoid possible divide error in nft_limit_init |
| |
| From: Eric Dumazet <edumazet@google.com> |
| |
| commit b895bdf5d643b6feb7c60856326dd4feb6981560 upstream. |
| |
| div_u64() divides u64 by u32. |
| |
| nft_limit_init() wants to divide u64 by u64, use the appropriate |
| math function (div64_u64) |
| |
| divide error: 0000 [#1] PREEMPT SMP KASAN |
| CPU: 1 PID: 8390 Comm: syz-executor188 Not tainted 5.12.0-rc4-syzkaller #0 |
| Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 |
| RIP: 0010:div_u64_rem include/linux/math64.h:28 [inline] |
| RIP: 0010:div_u64 include/linux/math64.h:127 [inline] |
| RIP: 0010:nft_limit_init+0x2a2/0x5e0 net/netfilter/nft_limit.c:85 |
| Code: ef 4c 01 eb 41 0f 92 c7 48 89 de e8 38 a5 22 fa 4d 85 ff 0f 85 97 02 00 00 e8 ea 9e 22 fa 4c 0f af f3 45 89 ed 31 d2 4c 89 f0 <49> f7 f5 49 89 c6 e8 d3 9e 22 fa 48 8d 7d 48 48 b8 00 00 00 00 00 |
| RSP: 0018:ffffc90009447198 EFLAGS: 00010246 |
| RAX: 0000000000000000 RBX: 0000200000000000 RCX: 0000000000000000 |
| RDX: 0000000000000000 RSI: ffffffff875152e6 RDI: 0000000000000003 |
| RBP: ffff888020f80908 R08: 0000200000000000 R09: 0000000000000000 |
| R10: ffffffff875152d8 R11: 0000000000000000 R12: ffffc90009447270 |
| R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 |
| FS: 000000000097a300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 |
| CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 |
| CR2: 00000000200001c4 CR3: 0000000026a52000 CR4: 00000000001506e0 |
| DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 |
| DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 |
| Call Trace: |
| nf_tables_newexpr net/netfilter/nf_tables_api.c:2675 [inline] |
| nft_expr_init+0x145/0x2d0 net/netfilter/nf_tables_api.c:2713 |
| nft_set_elem_expr_alloc+0x27/0x280 net/netfilter/nf_tables_api.c:5160 |
| nf_tables_newset+0x1997/0x3150 net/netfilter/nf_tables_api.c:4321 |
| nfnetlink_rcv_batch+0x85a/0x21b0 net/netfilter/nfnetlink.c:456 |
| nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:580 [inline] |
| nfnetlink_rcv+0x3af/0x420 net/netfilter/nfnetlink.c:598 |
| 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 |
| entry_SYSCALL_64_after_hwframe+0x44/0xae |
| |
| Fixes: c26844eda9d4 ("netfilter: nf_tables: Fix nft limit burst handling") |
| Fixes: 3e0f64b7dd31 ("netfilter: nft_limit: fix packet ratelimiting") |
| Signed-off-by: Eric Dumazet <edumazet@google.com> |
| Diagnosed-by: Luigi Rizzo <lrizzo@google.com> |
| Reported-by: syzbot <syzkaller@googlegroups.com> |
| Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/netfilter/nft_limit.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/net/netfilter/nft_limit.c |
| +++ b/net/netfilter/nft_limit.c |
| @@ -76,13 +76,13 @@ static int nft_limit_init(struct nft_lim |
| return -EOVERFLOW; |
| |
| if (pkts) { |
| - tokens = div_u64(limit->nsecs, limit->rate) * limit->burst; |
| + tokens = div64_u64(limit->nsecs, limit->rate) * limit->burst; |
| } else { |
| /* The token bucket size limits the number of tokens can be |
| * accumulated. tokens_max specifies the bucket size. |
| * tokens_max = unit * (rate + burst) / rate. |
| */ |
| - tokens = div_u64(limit->nsecs * (limit->rate + limit->burst), |
| + tokens = div64_u64(limit->nsecs * (limit->rate + limit->burst), |
| limit->rate); |
| } |
| |