From: Xin Long <lucien.xin@gmail.com>
To: network dev <netdev@vger.kernel.org>, linux-sctp@vger.kernel.org
Cc: davem@davemloft.net, kuba@kernel.org,
Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
Neil Horman <nhorman@tuxdriver.com>
Subject: [PATCH net] sctp: check asoc strreset_chunk in sctp_generate_reconf_event
Date: Wed, 20 Apr 2022 16:52:41 -0400 [thread overview]
Message-ID: <3000f8b12920ae81b84dceead6dcc90bb00c0403.1650487961.git.lucien.xin@gmail.com> (raw)
A null pointer reference issue can be triggered when the response of a
stream reconf request arrives after the timer is triggered, such as:
send Incoming SSN Reset Request --->
CPU0:
reconf timer is triggered,
go to the handler code before hold sk lock
<--- reply with Outgoing SSN Reset Request
CPU1:
process Outgoing SSN Reset Request,
and set asoc->strreset_chunk to NULL
CPU0:
continue the handler code, hold sk lock,
and try to hold asoc->strreset_chunk, crash!
In Ying Xu's testing, the call trace is:
[ ] BUG: kernel NULL pointer dereference, address: 0000000000000010
[ ] RIP: 0010:sctp_chunk_hold+0xe/0x40 [sctp]
[ ] Call Trace:
[ ] <IRQ>
[ ] sctp_sf_send_reconf+0x2c/0x100 [sctp]
[ ] sctp_do_sm+0xa4/0x220 [sctp]
[ ] sctp_generate_reconf_event+0xbd/0xe0 [sctp]
[ ] call_timer_fn+0x26/0x130
This patch is to fix it by returning from the timer handler if asoc
strreset_chunk is already set to NULL.
Fixes: 7b9438de0cd4 ("sctp: add stream reconf timer")
Reported-by: Ying Xu <yinxu@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
---
net/sctp/sm_sideeffect.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index b3815b568e8e..463c4a58d2c3 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -458,6 +458,10 @@ void sctp_generate_reconf_event(struct timer_list *t)
goto out_unlock;
}
+ /* This happens when the response arrives after the timer is triggered. */
+ if (!asoc->strreset_chunk)
+ goto out_unlock;
+
error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_RECONF),
asoc->state, asoc->ep, asoc,
--
2.31.1
next reply other threads:[~2022-04-20 20:52 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-20 20:52 Xin Long [this message]
2022-04-21 10:18 ` [PATCH net] sctp: check asoc strreset_chunk in sctp_generate_reconf_event David Miller
2022-04-21 15:04 ` Xin Long
2022-04-23 13:18 ` Marcelo Ricardo Leitner
2022-04-23 21:40 ` patchwork-bot+netdevbpf
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