netfilter: nft_limit: avoid possible divide error in nft_limit_init

In the Linux kernel, the following vulnerability has been resolved:

netfilter: nft_limit: avoid possible divide error in nft_limit_init

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