From: Stanislav Fomichev <sdf@google.com>
To: netdev@vger.kernel.org
Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, Stanislav Fomichev <sdf@google.com>,
Paul Mackerras <paulus@samba.org>,
linux-ppp@vger.kernel.org,
syzbot+41cab52ab62ee99ed24a@syzkaller.appspotmail.com
Subject: [PATCH net-next] ppp: associate skb with a device at tx
Date: Mon, 21 Nov 2022 10:29:13 -0800 [thread overview]
Message-ID: <20221121182913.2166006-1-sdf@google.com> (raw)
Syzkaller triggered flow dissector warning with the following:
r0 = openat$ppp(0xffffffffffffff9c, &(0x7f0000000000), 0xc0802, 0x0)
ioctl$PPPIOCNEWUNIT(r0, 0xc004743e, &(0x7f00000000c0))
ioctl$PPPIOCSACTIVE(r0, 0x40107446, &(0x7f0000000240)={0x2, &(0x7f0000000180)=[{0x20, 0x0, 0x0, 0xfffff034}, {0x6}]})
pwritev(r0, &(0x7f0000000040)=[{&(0x7f0000000140)='\x00!', 0x2}], 0x1, 0x0, 0x0)
[ 9.485814] WARNING: CPU: 3 PID: 329 at net/core/flow_dissector.c:1016 __skb_flow_dissect+0x1ee0/0x1fa0
[ 9.485929] skb_get_poff+0x53/0xa0
[ 9.485937] bpf_skb_get_pay_offset+0xe/0x20
[ 9.485944] ? ppp_send_frame+0xc2/0x5b0
[ 9.485949] ? _raw_spin_unlock_irqrestore+0x40/0x60
[ 9.485958] ? __ppp_xmit_process+0x7a/0xe0
[ 9.485968] ? ppp_xmit_process+0x5b/0xb0
[ 9.485974] ? ppp_write+0x12a/0x190
[ 9.485981] ? do_iter_write+0x18e/0x2d0
[ 9.485987] ? __import_iovec+0x30/0x130
[ 9.485997] ? do_pwritev+0x1b6/0x240
[ 9.486016] ? trace_hardirqs_on+0x47/0x50
[ 9.486023] ? __x64_sys_pwritev+0x24/0x30
[ 9.486026] ? do_syscall_64+0x3d/0x80
[ 9.486031] ? entry_SYSCALL_64_after_hwframe+0x63/0xcd
Flow dissector tries to find skb net namespace either via device
or via socket. Neigher is set in ppp_send_frame, so let's manually
use ppp->dev.
Cc: Paul Mackerras <paulus@samba.org>
Cc: linux-ppp@vger.kernel.org
Reported-by: syzbot+41cab52ab62ee99ed24a@syzkaller.appspotmail.com
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
drivers/net/ppp/ppp_generic.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index 9206c660a72e..d4c821c8cf57 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -1743,6 +1743,8 @@ ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
int len;
unsigned char *cp;
+ skb->dev = ppp->dev;
+
if (proto < 0x8000) {
#ifdef CONFIG_PPP_FILTER
/* check if we should pass this packet */
--
2.38.1.584.g0f3c55d4c2-goog
next reply other threads:[~2022-11-21 18:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-21 18:29 Stanislav Fomichev [this message]
2022-11-23 13:00 ` [PATCH net-next] ppp: associate skb with a device at tx patchwork-bot+netdevbpf
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