* [PATCH v2 net 0/3] net: af_packet: be careful when expanding mac header size
@ 2022-06-02 16:18 Eric Dumazet
2022-06-02 16:18 ` [PATCH v2 net 1/3] net: CONFIG_DEBUG_NET depends on CONFIG_NET Eric Dumazet
` (3 more replies)
0 siblings, 4 replies; 6+ messages in thread
From: Eric Dumazet @ 2022-06-02 16:18 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: netdev, Willem de Bruijn, Eric Dumazet, Eric Dumazet
From: Eric Dumazet <edumazet@google.com>
A recent regression in af_packet needed a preliminary debug patch,
which will presumably be useful for next bugs hunting.
The af_packet fix is to make sure MAC headers are contained in
skb linear part, as GSO stack requests.
v2: CONFIG_DEBUG_NET depends on CONFIG_NET to avoid compile
errors found by kernel bots.
Eric Dumazet (3):
net: CONFIG_DEBUG_NET depends on CONFIG_NET
net: add debug info to __skb_pull()
net/af_packet: make sure to pull mac header
include/linux/skbuff.h | 9 ++++++++-
net/Kconfig.debug | 2 +-
net/packet/af_packet.c | 6 ++++--
3 files changed, 13 insertions(+), 4 deletions(-)
--
2.36.1.255.ge46751e96f-goog
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v2 net 1/3] net: CONFIG_DEBUG_NET depends on CONFIG_NET
2022-06-02 16:18 [PATCH v2 net 0/3] net: af_packet: be careful when expanding mac header size Eric Dumazet
@ 2022-06-02 16:18 ` Eric Dumazet
2022-06-02 16:18 ` [PATCH v2 net 2/3] net: add debug info to __skb_pull() Eric Dumazet
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Eric Dumazet @ 2022-06-02 16:18 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: netdev, Willem de Bruijn, Eric Dumazet, Eric Dumazet
From: Eric Dumazet <edumazet@google.com>
It makes little sense to debug networking stacks
if networking is not compiled in.
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/Kconfig.debug | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/Kconfig.debug b/net/Kconfig.debug
index a5781cf63b16b32e5360df1ca26a753b6505d81f..e6ae11cc2fb7cb90e6a0c063d2135ee1839c3ead 100644
--- a/net/Kconfig.debug
+++ b/net/Kconfig.debug
@@ -20,7 +20,7 @@ config NET_NS_REFCNT_TRACKER
config DEBUG_NET
bool "Add generic networking debug"
- depends on DEBUG_KERNEL
+ depends on DEBUG_KERNEL && NET
help
Enable extra sanity checks in networking.
This is mostly used by fuzzers, but is safe to select.
--
2.36.1.255.ge46751e96f-goog
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 net 2/3] net: add debug info to __skb_pull()
2022-06-02 16:18 [PATCH v2 net 0/3] net: af_packet: be careful when expanding mac header size Eric Dumazet
2022-06-02 16:18 ` [PATCH v2 net 1/3] net: CONFIG_DEBUG_NET depends on CONFIG_NET Eric Dumazet
@ 2022-06-02 16:18 ` Eric Dumazet
2022-06-02 16:18 ` [PATCH v2 net 3/3] net/af_packet: make sure to pull mac header Eric Dumazet
2022-06-02 18:20 ` [PATCH v2 net 0/3] net: af_packet: be careful when expanding mac header size patchwork-bot+netdevbpf
3 siblings, 0 replies; 6+ messages in thread
From: Eric Dumazet @ 2022-06-02 16:18 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: netdev, Willem de Bruijn, Eric Dumazet, Eric Dumazet
From: Eric Dumazet <edumazet@google.com>
While analyzing yet another syzbot report, I found the following
patch very useful. It allows to better understand what went wrong.
This debug info is only enabled if CONFIG_DEBUG_NET=y,
which is the case for syzbot builds.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
---
include/linux/skbuff.h | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index da96f0d3e753fb7996631bc9350c0c8e0ec5966e..d3d10556f0faea8c8c1deed5715716d4916011d1 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2696,7 +2696,14 @@ void *skb_pull(struct sk_buff *skb, unsigned int len);
static inline void *__skb_pull(struct sk_buff *skb, unsigned int len)
{
skb->len -= len;
- BUG_ON(skb->len < skb->data_len);
+ if (unlikely(skb->len < skb->data_len)) {
+#if defined(CONFIG_DEBUG_NET)
+ skb->len += len;
+ pr_err("__skb_pull(len=%u)\n", len);
+ skb_dump(KERN_ERR, skb, false);
+#endif
+ BUG();
+ }
return skb->data += len;
}
--
2.36.1.255.ge46751e96f-goog
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 net 3/3] net/af_packet: make sure to pull mac header
2022-06-02 16:18 [PATCH v2 net 0/3] net: af_packet: be careful when expanding mac header size Eric Dumazet
2022-06-02 16:18 ` [PATCH v2 net 1/3] net: CONFIG_DEBUG_NET depends on CONFIG_NET Eric Dumazet
2022-06-02 16:18 ` [PATCH v2 net 2/3] net: add debug info to __skb_pull() Eric Dumazet
@ 2022-06-02 16:18 ` Eric Dumazet
2022-06-02 19:49 ` Michael S. Tsirkin
2022-06-02 18:20 ` [PATCH v2 net 0/3] net: af_packet: be careful when expanding mac header size patchwork-bot+netdevbpf
3 siblings, 1 reply; 6+ messages in thread
From: Eric Dumazet @ 2022-06-02 16:18 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: netdev, Willem de Bruijn, Eric Dumazet, Eric Dumazet, syzbot,
Hangbin Liu, Michael S . Tsirkin
From: Eric Dumazet <edumazet@google.com>
GSO assumes skb->head contains link layer headers.
tun device in some case can provide base 14 bytes,
regardless of VLAN being used or not.
After blamed commit, we can end up setting a network
header offset of 18+, we better pull the missing
bytes to avoid a posible crash in GSO.
syzbot report was:
kernel BUG at include/linux/skbuff.h:2699!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 3601 Comm: syz-executor210 Not tainted 5.18.0-syzkaller-11338-g2c5ca23f7414 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__skb_pull include/linux/skbuff.h:2699 [inline]
RIP: 0010:skb_mac_gso_segment+0x48f/0x530 net/core/gro.c:136
Code: 00 48 c7 c7 00 96 d4 8a c6 05 cb d3 45 06 01 e8 26 bb d0 01 e9 2f fd ff ff 49 c7 c4 ea ff ff ff e9 f1 fe ff ff e8 91 84 19 fa <0f> 0b 48 89 df e8 97 44 66 fa e9 7f fd ff ff e8 ad 44 66 fa e9 48
RSP: 0018:ffffc90002e2f4b8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000012 RCX: 0000000000000000
RDX: ffff88805bb58000 RSI: ffffffff8760ed0f RDI: 0000000000000004
RBP: 0000000000005dbc R08: 0000000000000004 R09: 0000000000000fe0
R10: 0000000000000fe4 R11: 0000000000000000 R12: 0000000000000fe0
R13: ffff88807194d780 R14: 1ffff920005c5e9b R15: 0000000000000012
FS: 000055555730f300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000200015c0 CR3: 0000000071ff8000 CR4: 0000000000350ee0
Call Trace:
<TASK>
__skb_gso_segment+0x327/0x6e0 net/core/dev.c:3411
skb_gso_segment include/linux/netdevice.h:4749 [inline]
validate_xmit_skb+0x6bc/0xf10 net/core/dev.c:3669
validate_xmit_skb_list+0xbc/0x120 net/core/dev.c:3719
sch_direct_xmit+0x3d1/0xbe0 net/sched/sch_generic.c:327
__dev_xmit_skb net/core/dev.c:3815 [inline]
__dev_queue_xmit+0x14a1/0x3a00 net/core/dev.c:4219
packet_snd net/packet/af_packet.c:3071 [inline]
packet_sendmsg+0x21cb/0x5550 net/packet/af_packet.c:3102
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:734
____sys_sendmsg+0x6eb/0x810 net/socket.c:2492
___sys_sendmsg+0xf3/0x170 net/socket.c:2546
__sys_sendmsg net/socket.c:2575 [inline]
__do_sys_sendmsg net/socket.c:2584 [inline]
__se_sys_sendmsg net/socket.c:2582 [inline]
__x64_sys_sendmsg+0x132/0x220 net/socket.c:2582
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f4b95da06c9
Code: 28 c3 e8 4a 15 00 00 66 2e 0f 1f 84 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd7defc4c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ffd7defc4f0 RCX: 00007f4b95da06c9
RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 0000000000000003 R08: bb1414ac00000050 R09: bb1414ac00000050
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd7defc4e0 R14: 00007ffd7defc4d8 R15: 00007ffd7defc4d4
</TASK>
Fixes: dfed913e8b55 ("net/af_packet: add VLAN support for AF_PACKET SOCK_RAW GSO")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
---
net/packet/af_packet.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 677f9cfa9660816a160a11bfa4c291431412005f..ca6e92a229239f9093900bf9249396cf0d410104 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1935,8 +1935,10 @@ static void packet_parse_headers(struct sk_buff *skb, struct socket *sock)
/* Move network header to the right position for VLAN tagged packets */
if (likely(skb->dev->type == ARPHRD_ETHER) &&
eth_type_vlan(skb->protocol) &&
- __vlan_get_protocol(skb, skb->protocol, &depth) != 0)
- skb_set_network_header(skb, depth);
+ __vlan_get_protocol(skb, skb->protocol, &depth) != 0) {
+ if (pskb_may_pull(skb, depth))
+ skb_set_network_header(skb, depth);
+ }
skb_probe_transport_header(skb);
}
--
2.36.1.255.ge46751e96f-goog
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v2 net 0/3] net: af_packet: be careful when expanding mac header size
2022-06-02 16:18 [PATCH v2 net 0/3] net: af_packet: be careful when expanding mac header size Eric Dumazet
` (2 preceding siblings ...)
2022-06-02 16:18 ` [PATCH v2 net 3/3] net/af_packet: make sure to pull mac header Eric Dumazet
@ 2022-06-02 18:20 ` patchwork-bot+netdevbpf
3 siblings, 0 replies; 6+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-06-02 18:20 UTC (permalink / raw)
To: Eric Dumazet; +Cc: davem, kuba, pabeni, netdev, willemb, edumazet
Hello:
This series was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:
On Thu, 2 Jun 2022 09:18:56 -0700 you wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> A recent regression in af_packet needed a preliminary debug patch,
> which will presumably be useful for next bugs hunting.
>
> The af_packet fix is to make sure MAC headers are contained in
> skb linear part, as GSO stack requests.
>
> [...]
Here is the summary with links:
- [v2,net,1/3] net: CONFIG_DEBUG_NET depends on CONFIG_NET
https://git.kernel.org/netdev/net/c/eb0b39efb7d9
- [v2,net,2/3] net: add debug info to __skb_pull()
https://git.kernel.org/netdev/net/c/22296a5c0cd3
- [v2,net,3/3] net/af_packet: make sure to pull mac header
https://git.kernel.org/netdev/net/c/e9d3f80935b6
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2 net 3/3] net/af_packet: make sure to pull mac header
2022-06-02 16:18 ` [PATCH v2 net 3/3] net/af_packet: make sure to pull mac header Eric Dumazet
@ 2022-06-02 19:49 ` Michael S. Tsirkin
0 siblings, 0 replies; 6+ messages in thread
From: Michael S. Tsirkin @ 2022-06-02 19:49 UTC (permalink / raw)
To: Eric Dumazet
Cc: David S . Miller, Jakub Kicinski, Paolo Abeni, netdev,
Willem de Bruijn, Eric Dumazet, syzbot, Hangbin Liu
On Thu, Jun 02, 2022 at 09:18:59AM -0700, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> GSO assumes skb->head contains link layer headers.
>
> tun device in some case can provide base 14 bytes,
> regardless of VLAN being used or not.
>
> After blamed commit, we can end up setting a network
> header offset of 18+, we better pull the missing
> bytes to avoid a posible crash in GSO.
>
> syzbot report was:
> kernel BUG at include/linux/skbuff.h:2699!
> invalid opcode: 0000 [#1] PREEMPT SMP KASAN
> CPU: 1 PID: 3601 Comm: syz-executor210 Not tainted 5.18.0-syzkaller-11338-g2c5ca23f7414 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:__skb_pull include/linux/skbuff.h:2699 [inline]
> RIP: 0010:skb_mac_gso_segment+0x48f/0x530 net/core/gro.c:136
> Code: 00 48 c7 c7 00 96 d4 8a c6 05 cb d3 45 06 01 e8 26 bb d0 01 e9 2f fd ff ff 49 c7 c4 ea ff ff ff e9 f1 fe ff ff e8 91 84 19 fa <0f> 0b 48 89 df e8 97 44 66 fa e9 7f fd ff ff e8 ad 44 66 fa e9 48
> RSP: 0018:ffffc90002e2f4b8 EFLAGS: 00010293
> RAX: 0000000000000000 RBX: 0000000000000012 RCX: 0000000000000000
> RDX: ffff88805bb58000 RSI: ffffffff8760ed0f RDI: 0000000000000004
> RBP: 0000000000005dbc R08: 0000000000000004 R09: 0000000000000fe0
> R10: 0000000000000fe4 R11: 0000000000000000 R12: 0000000000000fe0
> R13: ffff88807194d780 R14: 1ffff920005c5e9b R15: 0000000000000012
> FS: 000055555730f300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00000000200015c0 CR3: 0000000071ff8000 CR4: 0000000000350ee0
> Call Trace:
> <TASK>
> __skb_gso_segment+0x327/0x6e0 net/core/dev.c:3411
> skb_gso_segment include/linux/netdevice.h:4749 [inline]
> validate_xmit_skb+0x6bc/0xf10 net/core/dev.c:3669
> validate_xmit_skb_list+0xbc/0x120 net/core/dev.c:3719
> sch_direct_xmit+0x3d1/0xbe0 net/sched/sch_generic.c:327
> __dev_xmit_skb net/core/dev.c:3815 [inline]
> __dev_queue_xmit+0x14a1/0x3a00 net/core/dev.c:4219
> packet_snd net/packet/af_packet.c:3071 [inline]
> packet_sendmsg+0x21cb/0x5550 net/packet/af_packet.c:3102
> sock_sendmsg_nosec net/socket.c:714 [inline]
> sock_sendmsg+0xcf/0x120 net/socket.c:734
> ____sys_sendmsg+0x6eb/0x810 net/socket.c:2492
> ___sys_sendmsg+0xf3/0x170 net/socket.c:2546
> __sys_sendmsg net/socket.c:2575 [inline]
> __do_sys_sendmsg net/socket.c:2584 [inline]
> __se_sys_sendmsg net/socket.c:2582 [inline]
> __x64_sys_sendmsg+0x132/0x220 net/socket.c:2582
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x46/0xb0
> RIP: 0033:0x7f4b95da06c9
> Code: 28 c3 e8 4a 15 00 00 66 2e 0f 1f 84 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffd7defc4c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00007ffd7defc4f0 RCX: 00007f4b95da06c9
> RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003
> RBP: 0000000000000003 R08: bb1414ac00000050 R09: bb1414ac00000050
> R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007ffd7defc4e0 R14: 00007ffd7defc4d8 R15: 00007ffd7defc4d4
> </TASK>
>
> Fixes: dfed913e8b55 ("net/af_packet: add VLAN support for AF_PACKET SOCK_RAW GSO")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reported-by: syzbot <syzkaller@googlegroups.com>
> Acked-by: Hangbin Liu <liuhangbin@gmail.com>
> Acked-by: Willem de Bruijn <willemb@google.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> net/packet/af_packet.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
> index 677f9cfa9660816a160a11bfa4c291431412005f..ca6e92a229239f9093900bf9249396cf0d410104 100644
> --- a/net/packet/af_packet.c
> +++ b/net/packet/af_packet.c
> @@ -1935,8 +1935,10 @@ static void packet_parse_headers(struct sk_buff *skb, struct socket *sock)
> /* Move network header to the right position for VLAN tagged packets */
> if (likely(skb->dev->type == ARPHRD_ETHER) &&
> eth_type_vlan(skb->protocol) &&
> - __vlan_get_protocol(skb, skb->protocol, &depth) != 0)
> - skb_set_network_header(skb, depth);
> + __vlan_get_protocol(skb, skb->protocol, &depth) != 0) {
> + if (pskb_may_pull(skb, depth))
> + skb_set_network_header(skb, depth);
> + }
>
> skb_probe_transport_header(skb);
> }
> --
> 2.36.1.255.ge46751e96f-goog
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-06-02 19:50 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-06-02 16:18 [PATCH v2 net 0/3] net: af_packet: be careful when expanding mac header size Eric Dumazet
2022-06-02 16:18 ` [PATCH v2 net 1/3] net: CONFIG_DEBUG_NET depends on CONFIG_NET Eric Dumazet
2022-06-02 16:18 ` [PATCH v2 net 2/3] net: add debug info to __skb_pull() Eric Dumazet
2022-06-02 16:18 ` [PATCH v2 net 3/3] net/af_packet: make sure to pull mac header Eric Dumazet
2022-06-02 19:49 ` Michael S. Tsirkin
2022-06-02 18:20 ` [PATCH v2 net 0/3] net: af_packet: be careful when expanding mac header size patchwork-bot+netdevbpf
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