Re: [moderation/CI] Re: netfilter: switch ipset to rhashtable

#syz upstream

On Thu, Aug 6, 2026 at 4:43 PM syzbot ci
<[email protected]> wrote:
>
> syzbot ci has tested the following series
>
> [v1] netfilter: switch ipset to rhashtable
> https://lore.kernel.org/all/[email protected]
> * [PATCH nf 1/7] netfilter: ipset: remove need to allocate memory on delete operations
> * [PATCH nf 2/7] netfilter: ipset: let destroy callbacks adjust ext mem size
> * [PATCH nf 3/7] netfilter: ipset: add rhashtable boilerplate stubs
> * [PATCH nf 4/7] netfilter: ipset: add rhltable boilerplate stubs
> * [PATCH nf 5/7] netfilter: ipset: replace internal hash table with rhashtable
> * [PATCH nf 6/7] netfilter: ipset: re-add forceadd support for rhashtable
> * [PATCH nf 7/7] netfilter: ipset: also report mem size for cidr storage to userspace
>
> and found the following issues:
> * UBSAN: shift-out-of-bounds in hash_netiface6_head
> * UBSAN: shift-out-of-bounds in hash_netportnet6_head
>
> Full report is available here:
> https://ci.syzbot.org/series/e7969a90-d2b3-4da4-8795-4c3794dae0f0
>
> ***
>
> UBSAN: shift-out-of-bounds in hash_netiface6_head
>
> tree:      nf
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/netfilter/nf.git
> base:      44871eadd07a7f004aa00cb87399461eea08c630
> arch:      amd64
> compiler:  Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
> config:    https://ci.syzbot.org/builds/81d26051-7806-406c-9355-fbf52dca8f68/config
> syz repro: https://ci.syzbot.org/findings/cb9f585e-5753-41c6-b732-20d1d77f5564/syz_repro
>
> ------------[ cut here ]------------
> UBSAN: shift-out-of-bounds in net/netfilter/ipset/ip_set_hash_gen.h:1120:46
> shift exponent 32 is too large for 32-bit type 'u32' (aka 'unsigned int')
> CPU: 1 UID: 0 PID: 5865 Comm: syz.2.19 Not tainted syzkaller #0 PREEMPT(full)
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
>  ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
>  __ubsan_handle_shift_out_of_bounds+0x36d/0x400 lib/ubsan.c:494
>  hash_netiface6_head+0x89e/0x970 net/netfilter/ipset/ip_set_hash_gen.h:1120
>  ip_set_dump_do+0x1476/0x1920 net/netfilter/ipset/ip_set_core.c:1664
>  netlink_dump+0x711/0xee0 net/netlink/af_netlink.c:2331
>  __netlink_dump_start+0x589/0x7b0 net/netlink/af_netlink.c:2446
>  netlink_dump_start include/linux/netlink.h:341 [inline]
>  ip_set_dump+0x15b/0x1f0 net/netfilter/ipset/ip_set_core.c:1730
>  nfnetlink_rcv_msg+0xcc2/0x12b0 net/netfilter/nfnetlink.c:300
>  netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
>  nfnetlink_rcv+0x2b9/0x28c0 net/netfilter/nfnetlink.c:667
>  netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
>  netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345
>  netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
>  sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775
>  __sock_sendmsg net/socket.c:790 [inline]
>  ____sys_sendmsg+0x54e/0x850 net/socket.c:2684
>  ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738
>  __sys_sendmsg net/socket.c:2770 [inline]
>  __do_sys_sendmsg net/socket.c:2775 [inline]
>  __se_sys_sendmsg net/socket.c:2773 [inline]
>  __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773
>  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>  do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f7b3159e019
> Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f7b323e2028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00007f7b31825fa0 RCX: 00007f7b3159e019
> RDX: 0000000000008080 RSI: 0000200000000180 RDI: 0000000000000004
> RBP: 00007f7b3163500c R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007f7b31826038 R14: 00007f7b31825fa0 R15: 00007ffdc35054d8
>  </TASK>
> ---[ end trace ]---
>
>
> ***
>
> UBSAN: shift-out-of-bounds in hash_netportnet6_head
>
> tree:      nf
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/netfilter/nf.git
> base:      44871eadd07a7f004aa00cb87399461eea08c630
> arch:      amd64
> compiler:  Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
> config:    https://ci.syzbot.org/builds/81d26051-7806-406c-9355-fbf52dca8f68/config
> syz repro: https://ci.syzbot.org/findings/0f098de1-ac6a-4b30-8a0d-ea1586a67851/syz_repro
>
> ------------[ cut here ]------------
> UBSAN: shift-out-of-bounds in net/netfilter/ipset/ip_set_hash_gen.h:1120:46
> shift exponent 32 is too large for 32-bit type 'u32' (aka 'unsigned int')
> CPU: 1 UID: 0 PID: 5838 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
>  ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
>  __ubsan_handle_shift_out_of_bounds+0x36d/0x400 lib/ubsan.c:494
>  hash_netportnet6_head+0x97a/0xa40 net/netfilter/ipset/ip_set_hash_gen.h:1120
>  ip_set_dump_do+0x1476/0x1920 net/netfilter/ipset/ip_set_core.c:1664
>  netlink_dump+0x711/0xee0 net/netlink/af_netlink.c:2331
>  __netlink_dump_start+0x589/0x7b0 net/netlink/af_netlink.c:2446
>  netlink_dump_start include/linux/netlink.h:341 [inline]
>  ip_set_dump+0x15b/0x1f0 net/netfilter/ipset/ip_set_core.c:1730
>  nfnetlink_rcv_msg+0xcc2/0x12b0 net/netfilter/nfnetlink.c:300
>  netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
>  nfnetlink_rcv+0x2b9/0x28c0 net/netfilter/nfnetlink.c:667
>  netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
>  netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345
>  netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
>  sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775
>  __sock_sendmsg net/socket.c:790 [inline]
>  ____sys_sendmsg+0x54e/0x850 net/socket.c:2684
>  ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738
>  __sys_sendmsg net/socket.c:2770 [inline]
>  __do_sys_sendmsg net/socket.c:2775 [inline]
>  __se_sys_sendmsg net/socket.c:2773 [inline]
>  __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773
>  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>  do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f44dc59e019
> Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f44dd41d028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00007f44dc825fa0 RCX: 00007f44dc59e019
> RDX: 0000000000000000 RSI: 0000200000000200 RDI: 0000000000000004
> RBP: 00007f44dc63500c R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007f44dc826038 R14: 00007f44dc825fa0 R15: 00007ffdbc9c05c8
>  </TASK>
> ---[ end trace ]---
>
>
> ***
>
> If these findings have caused you to resend the series or submit a
> separate fix, please add the following tag to your commit message:
>   Tested-by: [email protected]
>
> ---
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>
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