* general protection fault in ip6_pol_route
@ 2025-02-04 13:47 YAN KANG
2025-02-04 14:07 ` Eric Dumazet
0 siblings, 1 reply; 3+ messages in thread
From: YAN KANG @ 2025-02-04 13:47 UTC (permalink / raw)
To: Eric Dumazet, David S. Miller, David Ahern, Jakub Kicinski,
Paolo Abeni, Simon Horman, netdev, linux-kernel
Dear maintainers,
I found a kernel bug titiled "general protection fault in ip6_pol_route" while using modified syzkaller fuzzing tool. I Itested it on the latest Linux upstream version (6.13.0-rc7) .
After preliminary analysis, the rootcause may be in ip6_pol_route function net/ipv6/route.c
res is a stack object. [1]
fib6_select_path(net, &res, fl6, oif, false, skb, strict) call may initialize res->nh.[2]
rt = rt6_get_pcpu_route( &res); [3]
pcpu_rt = this_cpu_read(*res->nh->rt6i_pcpu); // *res->nh is NULL, crash
in [2], res->nh can be initialized in several ways,possibly one of which initializes it to NULL.
Unfortunately, I don't have any reproducer for this bug yet.
If you fix this issue, please add the following tag to the commit:
Reported-by: yan kang <kangyan91@outlook.com>
Reported-by: yue sun <samsun1006219@gmail.com
I hope it helps.
Best regards
yan kang
Kernel crash log is listed below.
==================================================================
crash log
==================================================================
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000013: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f]
CPU: 1 UID: 0 PID: 12 Comm: kworker/u8:1 Not tainted 6.13.0-rc7-00003-gd4774759e15b-dirty #87
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Workqueue: ipv6_addrconf addrconf_dad_work
RIP: 0010:rt6_get_pcpu_route net/ipv6/route.c:1411 [inline]
RIP: 0010:ip6_pol_route+0x3be/0x1210 net/ipv6/route.c:2264
Code: f7 4d 85 f6 0f 84 40 03 00 00 e8 3d 8f cb f7 49 8d be 98 00 00 00 4c 89 f3 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 1a 0d 00 00 45 8b ae 98 00 00
RSP: 0018:ffffc900001e87d0 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000004 RCX: ffffffff89cd3195
RDX: 0000000000000013 RSI: ffffffff89cd31a3 RDI: 000000000000009c
RBP: ffff88812a010000 R08: 0000000000000001 R09: ffff888110288000
R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000080
R13: ffffc900001e8b20 R14: 0000000000000004 R15: ffffc900001e8860
FS: 0000000000000000(0000) GS:ffff888135e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc23d35b344 CR3: 000000010570e000 CR4: 0000000000752ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<IRQ>
pol_lookup_func include/net/ip6_fib.h:616 [inline]
fib6_rule_lookup+0x538/0x720 net/ipv6/fib6_rules.c:117
ip6_route_input_lookup net/ipv6/route.c:2300 [inline]
ip6_route_input+0x66e/0xc20 net/ipv6/route.c:2596
ip6_rcv_finish_core.constprop.0+0x1aa/0x5e0 net/ipv6/ip6_input.c:66
ip6_rcv_finish net/ipv6/ip6_input.c:77 [inline]
NF_HOOK include/linux/netfilter.h:314 [inline]
NF_HOOK include/linux/netfilter.h:308 [inline]
ipv6_rcv+0x1e7/0x690 net/ipv6/ip6_input.c:309
__netif_receive_skb_one_core+0x12e/0x1f0 net/core/dev.c:5672
__netif_receive_skb+0x1d/0x150 net/core/dev.c:5785
process_backlog+0x319/0x1460 net/core/dev.c:6117
__napi_poll.constprop.0+0xb6/0x540 net/core/dev.c:6877
napi_poll net/core/dev.c:6946 [inline]
net_rx_action+0x9d2/0xe30 net/core/dev.c:7068
handle_softirqs+0x1bf/0x850 kernel/softirq.c:554
do_softirq kernel/softirq.c:455 [inline]
do_softirq+0xac/0xe0 kernel/softirq.c:442
</IRQ>
<TASK>
__local_bh_enable_ip+0x100/0x120 kernel/softirq.c:382
local_bh_enable include/linux/bottom_half.h:33 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline]
__dev_queue_xmit+0x1b98/0x4160 net/core/dev.c:4461
dev_queue_xmit include/linux/netdevice.h:3168 [inline]
neigh_resolve_output net/core/neighbour.c:1514 [inline]
neigh_resolve_output+0x58e/0x900 net/core/neighbour.c:1494
neigh_output include/net/neighbour.h:539 [inline]
ip6_finish_output2+0xae5/0x1ec0 net/ipv6/ip6_output.c:141
__ip6_finish_output net/ipv6/ip6_output.c:215 [inline]
ip6_finish_output+0x713/0x1230 net/ipv6/ip6_output.c:226
NF_HOOK_COND include/linux/netfilter.h:303 [inline]
ip6_output+0x203/0x550 net/ipv6/ip6_output.c:247
dst_output include/net/dst.h:450 [inline]
NF_HOOK include/linux/netfilter.h:314 [inline]
ndisc_send_skb+0xa65/0x1c70 net/ipv6/ndisc.c:511
ndisc_send_ns+0xb5/0x130 net/ipv6/ndisc.c:669
addrconf_dad_work+0xd3a/0x1610 net/ipv6/addrconf.c:4303
process_one_work+0x99f/0x1bb0 kernel/workqueue.c:3229
process_scheduled_works kernel/workqueue.c:3310 [inline]
worker_thread+0x66e/0xe80 kernel/workqueue.c:3391
kthread+0x2c7/0x3b0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:rt6_get_pcpu_route net/ipv6/route.c:1411 [inline]
RIP: 0010:ip6_pol_route+0x3be/0x1210 net/ipv6/route.c:2264
Code: f7 4d 85 f6 0f 84 40 03 00 00 e8 3d 8f cb f7 49 8d be 98 00 00 00 4c 89 f3 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 1a 0d 00 00 45 8b ae 98 00 00
RSP: 0018:ffffc900001e87d0 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000004 RCX: ffffffff89cd3195
RDX: 0000000000000013 RSI: ffffffff89cd31a3 RDI: 000000000000009c
RBP: ffff88812a010000 R08: 0000000000000001 R09: ffff888110288000
R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000080
R13: ffffc900001e8b20 R14: 0000000000000004 R15: ffffc900001e8860
FS: 0000000000000000(0000) GS:ffff888135e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc23d35b344 CR3: 000000010570e000 CR4: 0000000000752ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400
PKRU: 55555554
----------------
Code disassembly (best guess):
0: f7 4d 85 f6 0f 84 40 testl $0x40840ff6,-0x7b(%rbp)
7: 03 00 add (%rax),%eax
9: 00 e8 add %ch,%al
b: 3d 8f cb f7 49 cmp $0x49f7cb8f,%eax
10: 8d be 98 00 00 00 lea 0x98(%rsi),%edi
16: 4c 89 f3 mov %r14,%rbx
19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
20: fc ff df
23: 48 89 fa mov %rdi,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax <-- trapping instruction
2e: 84 c0 test %al,%al
30: 74 08 je 0x3a
32: 3c 03 cmp $0x3,%al
34: 0f 8e 1a 0d 00 00 jle 0xd54
3a: 45 rex.RB
3b: 8b .byte 0x8b
3c: ae scas %es:(%rdi),%al
3d: 98 cwtl
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: general protection fault in ip6_pol_route
2025-02-04 13:47 general protection fault in ip6_pol_route YAN KANG
@ 2025-02-04 14:07 ` Eric Dumazet
2025-02-05 11:33 ` Hillf Danton
0 siblings, 1 reply; 3+ messages in thread
From: Eric Dumazet @ 2025-02-04 14:07 UTC (permalink / raw)
To: YAN KANG
Cc: David S. Miller, David Ahern, Jakub Kicinski, Paolo Abeni,
Simon Horman, netdev, linux-kernel
On Tue, Feb 4, 2025 at 2:47 PM YAN KANG <kangyan91@outlook.com> wrote:
>
> Dear maintainers,
>
> I found a kernel bug titiled "general protection fault in ip6_pol_route" while using modified syzkaller fuzzing tool. I Itested it on the latest Linux upstream version (6.13.0-rc7) .
>
>
> After preliminary analysis, the rootcause may be in ip6_pol_route function net/ipv6/route.c
> res is a stack object. [1]
> fib6_select_path(net, &res, fl6, oif, false, skb, strict) call may initialize res->nh.[2]
> rt = rt6_get_pcpu_route( &res); [3]
> pcpu_rt = this_cpu_read(*res->nh->rt6i_pcpu); // *res->nh is NULL, crash
>
> in [2], res->nh can be initialized in several ways,possibly one of which initializes it to NULL.
>
> Unfortunately, I don't have any reproducer for this bug yet.
>
> If you fix this issue, please add the following tag to the commit:
> Reported-by: yan kang <kangyan91@outlook.com>
> Reported-by: yue sun <samsun1006219@gmail.com
>
>
This is a dup of a syzbot report under investigation.
Unless you have a repro and/or a patch, I would recommend you not
sending these fuzzer reports anymore.
Releasing such reports without a fix is an obvious security risk.
Thank you.
> I hope it helps.
> Best regards
> yan kang
>
> Kernel crash log is listed below.
>
> ==================================================================
> crash log
> ==================================================================
>
> Oops: general protection fault, probably for non-canonical address 0xdffffc0000000013: 0000 [#1] PREEMPT SMP KASAN NOPTI
> KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f]
> CPU: 1 UID: 0 PID: 12 Comm: kworker/u8:1 Not tainted 6.13.0-rc7-00003-gd4774759e15b-dirty #87
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
> Workqueue: ipv6_addrconf addrconf_dad_work
> RIP: 0010:rt6_get_pcpu_route net/ipv6/route.c:1411 [inline]
> RIP: 0010:ip6_pol_route+0x3be/0x1210 net/ipv6/route.c:2264
> Code: f7 4d 85 f6 0f 84 40 03 00 00 e8 3d 8f cb f7 49 8d be 98 00 00 00 4c 89 f3 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 1a 0d 00 00 45 8b ae 98 00 00
> RSP: 0018:ffffc900001e87d0 EFLAGS: 00010203
> RAX: dffffc0000000000 RBX: 0000000000000004 RCX: ffffffff89cd3195
> RDX: 0000000000000013 RSI: ffffffff89cd31a3 RDI: 000000000000009c
> RBP: ffff88812a010000 R08: 0000000000000001 R09: ffff888110288000
> R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000080
> R13: ffffc900001e8b20 R14: 0000000000000004 R15: ffffc900001e8860
> FS: 0000000000000000(0000) GS:ffff888135e00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fc23d35b344 CR3: 000000010570e000 CR4: 0000000000752ef0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400
> PKRU: 55555554
> Call Trace:
> <IRQ>
> pol_lookup_func include/net/ip6_fib.h:616 [inline]
> fib6_rule_lookup+0x538/0x720 net/ipv6/fib6_rules.c:117
> ip6_route_input_lookup net/ipv6/route.c:2300 [inline]
> ip6_route_input+0x66e/0xc20 net/ipv6/route.c:2596
> ip6_rcv_finish_core.constprop.0+0x1aa/0x5e0 net/ipv6/ip6_input.c:66
> ip6_rcv_finish net/ipv6/ip6_input.c:77 [inline]
> NF_HOOK include/linux/netfilter.h:314 [inline]
> NF_HOOK include/linux/netfilter.h:308 [inline]
> ipv6_rcv+0x1e7/0x690 net/ipv6/ip6_input.c:309
> __netif_receive_skb_one_core+0x12e/0x1f0 net/core/dev.c:5672
> __netif_receive_skb+0x1d/0x150 net/core/dev.c:5785
> process_backlog+0x319/0x1460 net/core/dev.c:6117
> __napi_poll.constprop.0+0xb6/0x540 net/core/dev.c:6877
> napi_poll net/core/dev.c:6946 [inline]
> net_rx_action+0x9d2/0xe30 net/core/dev.c:7068
> handle_softirqs+0x1bf/0x850 kernel/softirq.c:554
> do_softirq kernel/softirq.c:455 [inline]
> do_softirq+0xac/0xe0 kernel/softirq.c:442
> </IRQ>
> <TASK>
> __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:382
> local_bh_enable include/linux/bottom_half.h:33 [inline]
> rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline]
> __dev_queue_xmit+0x1b98/0x4160 net/core/dev.c:4461
> dev_queue_xmit include/linux/netdevice.h:3168 [inline]
> neigh_resolve_output net/core/neighbour.c:1514 [inline]
> neigh_resolve_output+0x58e/0x900 net/core/neighbour.c:1494
> neigh_output include/net/neighbour.h:539 [inline]
> ip6_finish_output2+0xae5/0x1ec0 net/ipv6/ip6_output.c:141
> __ip6_finish_output net/ipv6/ip6_output.c:215 [inline]
> ip6_finish_output+0x713/0x1230 net/ipv6/ip6_output.c:226
> NF_HOOK_COND include/linux/netfilter.h:303 [inline]
> ip6_output+0x203/0x550 net/ipv6/ip6_output.c:247
> dst_output include/net/dst.h:450 [inline]
> NF_HOOK include/linux/netfilter.h:314 [inline]
> ndisc_send_skb+0xa65/0x1c70 net/ipv6/ndisc.c:511
> ndisc_send_ns+0xb5/0x130 net/ipv6/ndisc.c:669
> addrconf_dad_work+0xd3a/0x1610 net/ipv6/addrconf.c:4303
> process_one_work+0x99f/0x1bb0 kernel/workqueue.c:3229
> process_scheduled_works kernel/workqueue.c:3310 [inline]
> worker_thread+0x66e/0xe80 kernel/workqueue.c:3391
> kthread+0x2c7/0x3b0 kernel/kthread.c:389
> ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
> ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
> </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:rt6_get_pcpu_route net/ipv6/route.c:1411 [inline]
> RIP: 0010:ip6_pol_route+0x3be/0x1210 net/ipv6/route.c:2264
> Code: f7 4d 85 f6 0f 84 40 03 00 00 e8 3d 8f cb f7 49 8d be 98 00 00 00 4c 89 f3 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 1a 0d 00 00 45 8b ae 98 00 00
> RSP: 0018:ffffc900001e87d0 EFLAGS: 00010203
> RAX: dffffc0000000000 RBX: 0000000000000004 RCX: ffffffff89cd3195
> RDX: 0000000000000013 RSI: ffffffff89cd31a3 RDI: 000000000000009c
> RBP: ffff88812a010000 R08: 0000000000000001 R09: ffff888110288000
> R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000080
> R13: ffffc900001e8b20 R14: 0000000000000004 R15: ffffc900001e8860
> FS: 0000000000000000(0000) GS:ffff888135e00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fc23d35b344 CR3: 000000010570e000 CR4: 0000000000752ef0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400
> PKRU: 55555554
> ----------------
> Code disassembly (best guess):
> 0: f7 4d 85 f6 0f 84 40 testl $0x40840ff6,-0x7b(%rbp)
> 7: 03 00 add (%rax),%eax
> 9: 00 e8 add %ch,%al
> b: 3d 8f cb f7 49 cmp $0x49f7cb8f,%eax
> 10: 8d be 98 00 00 00 lea 0x98(%rsi),%edi
> 16: 4c 89 f3 mov %r14,%rbx
> 19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
> 20: fc ff df
> 23: 48 89 fa mov %rdi,%rdx
> 26: 48 c1 ea 03 shr $0x3,%rdx
> * 2a: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax <-- trapping instruction
> 2e: 84 c0 test %al,%al
> 30: 74 08 je 0x3a
> 32: 3c 03 cmp $0x3,%al
> 34: 0f 8e 1a 0d 00 00 jle 0xd54
> 3a: 45 rex.RB
> 3b: 8b .byte 0x8b
> 3c: ae scas %es:(%rdi),%al
> 3d: 98 cwtl
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: general protection fault in ip6_pol_route
2025-02-04 14:07 ` Eric Dumazet
@ 2025-02-05 11:33 ` Hillf Danton
0 siblings, 0 replies; 3+ messages in thread
From: Hillf Danton @ 2025-02-05 11:33 UTC (permalink / raw)
To: Eric Dumazet; +Cc: YAN KANG, netdev, LKML
On Tue, 4 Feb 2025 15:07:49 +0100 Eric Dumazet <edumazet@google.com>
> On Tue, Feb 4, 2025 at 2:47 PM YAN KANG <kangyan91@outlook.com> wrote:
> >
> > Dear maintainers,
> >
> > I found a kernel bug titiled "general protection fault in ip6_pol_route" while using modified syzkaller fuzzing tool. I Itested it on the latest Linux upstream version (6.13.0-rc7) .
> >
> >
> > After preliminary analysis, the rootcause may be in ip6_pol_route function net/ipv6/route.c
> > res is a stack object. [1]
> > fib6_select_path(net, &res, fl6, oif, false, skb, strict) call may initialize res->nh.[2]
> > rt = rt6_get_pcpu_route( &res); [3]
> > pcpu_rt = this_cpu_read(*res->nh->rt6i_pcpu); // *res->nh is NULL, crash
> >
> > in [2], res->nh can be initialized in several ways,possibly one of which initializes it to NULL.
> >
> > Unfortunately, I don't have any reproducer for this bug yet.
> >
> > If you fix this issue, please add the following tag to the commit:
> > Reported-by: yan kang <kangyan91@outlook.com>
> > Reported-by: yue sun <samsun1006219@gmail.com
> >
> This is a dup of a syzbot report under investigation.
>
> Unless you have a repro and/or a patch, I would recommend you not
> sending these fuzzer reports anymore.
>
> Releasing such reports without a fix is an obvious security risk.
>
Can you specify a bit why report like this one links to security risk, Eric,
given no fix yet delivered to the syzbot report [1] so far?
[1] https://yhbt.net/lore/lkml/67a21f26.050a0220.163cdc.0068.GAE@google.com/
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2025-02-05 12:08 UTC | newest]
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2025-02-04 13:47 general protection fault in ip6_pol_route YAN KANG
2025-02-04 14:07 ` Eric Dumazet
2025-02-05 11:33 ` Hillf Danton
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