On Thu, Dec 17, 2020 at 05:53:18PM +0300, Vasily Averin wrote: > htable_bits() can call jhash_size(32) and trigger shift-out-of-bounds > > UBSAN: shift-out-of-bounds in net/netfilter/ipset/ip_set_hash_gen.h:151:6 > shift exponent 32 is too large for 32-bit type 'unsigned int' > CPU: 0 PID: 8498 Comm: syz-executor519 > Not tainted 5.10.0-rc7-next-20201208-syzkaller #0 > Call Trace: > __dump_stack lib/dump_stack.c:79 [inline] > dump_stack+0x107/0x163 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:395 > htable_bits net/netfilter/ipset/ip_set_hash_gen.h:151 [inline] > hash_mac_create.cold+0x58/0x9b net/netfilter/ipset/ip_set_hash_gen.h:1524 > ip_set_create+0x610/0x1380 net/netfilter/ipset/ip_set_core.c:1115 > nfnetlink_rcv_msg+0xecc/0x1180 net/netfilter/nfnetlink.c:252 > netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494 > nfnetlink_rcv+0x1ac/0x420 net/netfilter/nfnetlink.c:600 > netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] > netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330 > netlink_sendmsg+0x907/0xe40 net/netlink/af_netlink.c:1919 > sock_sendmsg_nosec net/socket.c:652 [inline] > sock_sendmsg+0xcf/0x120 net/socket.c:672 > ____sys_sendmsg+0x6e8/0x810 net/socket.c:2345 > ___sys_sendmsg+0xf3/0x170 net/socket.c:2399 > __sys_sendmsg+0xe5/0x1b0 net/socket.c:2432 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > This patch replaces htable_bits() by simple fls(hashsize - 1) call: > it alone returns valid nbits both for round and non-round hashsizes. > It is normal to set any nbits here because it is validated inside > following htable_size() call which returns 0 for nbits>31. Applied, thanks.
