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KASAN: stack-out-of-bounds Write in nft_ct_get_eval

Status: closed as invalid on 2025/12/11 18:37
Subsystems: netfilter
[Documentation on labels]
First crash: 41d, last: 41d

Sample crash report:
==================================================================
BUG: KASAN: stack-out-of-bounds in nft_ct_get_eval+0x100d/0x15c0 net/netfilter/nft_ct.c:-1
Write of size 16 at addr ffffc90000a0868c by task syz.5.5707/28826

CPU: 1 UID: 0 PID: 28826 Comm: syz.5.5707 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:200
 __asan_memcpy+0x40/0x70 mm/kasan/shadow.c:106
 nft_ct_get_eval+0x100d/0x15c0 net/netfilter/nft_ct.c:-1
 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
 nft_do_chain+0x40c/0x1920 net/netfilter/nf_tables_core.c:285
 nft_do_chain_ipv4+0x154/0x210 net/netfilter/nft_chain_filter.c:23
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623
 nf_hook include/linux/netfilter.h:273 [inline]
 NF_HOOK+0x206/0x3a0 include/linux/netfilter.h:316
 __netif_receive_skb_one_core net/core/dev.c:6079 [inline]
 __netif_receive_skb+0x143/0x380 net/core/dev.c:6192
 process_backlog+0x60e/0x14f0 net/core/dev.c:6544
 __napi_poll+0xc7/0x360 net/core/dev.c:7594
 napi_poll net/core/dev.c:7657 [inline]
 net_rx_action+0x5f7/0xdf0 net/core/dev.c:7784
 handle_softirqs+0x286/0x870 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:sk_peek_offset_bwd include/net/sock.h:725 [inline]
RIP: 0010:sk_peek_offset_fwd include/net/sock.h:733 [inline]
RIP: 0010:__unix_dgram_recvmsg+0x8b4/0xd60 net/unix/af_unix.c:2673
Code: df 48 8b 4c 24 48 0f b6 04 01 84 c0 4c 8b 7c 24 28 48 8b 54 24 18 0f 85 db 03 00 00 8b 1a bf ff ff ff ff 89 de e8 0c 9c cf f7 <85> db 0f 89 1a 02 00 00 e8 bf 97 cf f7 49 8d 5c 24 38 48 89 d8 48
RSP: 0018:ffffc900048776a0 EFLAGS: 00000297
RAX: ffffffff89f06c04 RBX: 00000000ffffffff RCX: 0000000000000002
RDX: ffff888030191e40 RSI: 00000000ffffffff RDI: 00000000ffffffff
RBP: ffffc90004877830 R08: ffffc9000487775f R09: 0000000000000000
R10: ffffc90004877740 R11: fffff5200090eeec R12: ffff8880925c4140
R13: 0000000080000002 R14: ffff8880925c4174 R15: 1ffff9200090eee4
 sock_recvmsg_nosec+0x186/0x1c0 net/socket.c:1078
 ____sys_recvmsg+0x3aa/0x460 net/socket.c:2848
 ___sys_recvmsg+0x1b5/0x510 net/socket.c:2892
 do_recvmmsg+0x36a/0x770 net/socket.c:2979
 __sys_recvmmsg+0x19d/0x280 net/socket.c:3061
 __do_compat_sys_recvmmsg_time32 net/compat.c:418 [inline]
 __se_compat_sys_recvmmsg_time32 net/compat.c:414 [inline]
 __ia32_compat_sys_recvmmsg_time32+0xbf/0xe0 net/compat.c:414
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xb6/0x2b0 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7f32539
Code: 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f540555c EFLAGS: 00000206 ORIG_RAX: 0000000000000151
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00000000800000c0
RDX: 0000000000010106 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

The buggy address belongs to a 0-page vmalloc region starting at 0xffffc90000a01000 allocated at map_irq_stack arch/x86/kernel/irq_64.c:49 [inline]
The buggy address belongs to a 0-page vmalloc region starting at 0xffffc90000a01000 allocated at irq_init_percpu_irqstack+0x342/0x4a0 arch/x86/kernel/irq_64.c:76
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xb8908
flags: 0xfff00000002000(reserved|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000002000 ffffea0002e24208 ffffea0002e24208 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffffc90000a08580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90000a08600: 00 00 00 00 f1 f1 f1 f1 00 00 00 00 00 00 00 00
>ffffc90000a08680: 00 00 f2 f2 f2 f2 00 00 00 00 00 00 00 00 00 00
                         ^
 ffffc90000a08700: 00 00 00 00 00 00 f2 f2 f2 f2 00 00 f3 f3 f3 f3
 ffffc90000a08780: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
==================================================================
----------------
Code disassembly (best guess):
   0:	df 48 8b             	fisttps -0x75(%rax)
   3:	4c 24 48             	rex.WR and $0x48,%al
   6:	0f b6 04 01          	movzbl (%rcx,%rax,1),%eax
   a:	84 c0                	test   %al,%al
   c:	4c 8b 7c 24 28       	mov    0x28(%rsp),%r15
  11:	48 8b 54 24 18       	mov    0x18(%rsp),%rdx
  16:	0f 85 db 03 00 00    	jne    0x3f7
  1c:	8b 1a                	mov    (%rdx),%ebx
  1e:	bf ff ff ff ff       	mov    $0xffffffff,%edi
  23:	89 de                	mov    %ebx,%esi
  25:	e8 0c 9c cf f7       	call   0xf7cf9c36
* 2a:	85 db                	test   %ebx,%ebx <-- trapping instruction
  2c:	0f 89 1a 02 00 00    	jns    0x24c
  32:	e8 bf 97 cf f7       	call   0xf7cf97f6
  37:	49 8d 5c 24 38       	lea    0x38(%r12),%rbx
  3c:	48 89 d8             	mov    %rbx,%rax
  3f:	48                   	rex.W

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/11 11:14 upstream 4427259cc7f7 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 KASAN: stack-out-of-bounds Write in nft_ct_get_eval
* Struck through repros no longer work on HEAD.