This is a note to let you know that I've just added the patch titled
sctp: leave the err path free in sctp_stream_init to sctp_stream_free
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sctp-leave-the-err-path-free-in-sctp_stream_init-to-.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 59e88348aee82011fb00db676d8ad971518e0003
Author: Xin Long <lucien.xin@xxxxxxxxx>
Date: Mon Jul 25 18:11:06 2022 -0400
sctp: leave the err path free in sctp_stream_init to sctp_stream_free
[ Upstream commit 181d8d2066c000ba0a0e6940a7ad80f1a0e68e9d ]
A NULL pointer dereference was reported by Wei Chen:
BUG: kernel NULL pointer dereference, address: 0000000000000000
RIP: 0010:__list_del_entry_valid+0x26/0x80
Call Trace:
<TASK>
sctp_sched_dequeue_common+0x1c/0x90
sctp_sched_prio_dequeue+0x67/0x80
__sctp_outq_teardown+0x299/0x380
sctp_outq_free+0x15/0x20
sctp_association_free+0xc3/0x440
sctp_do_sm+0x1ca7/0x2210
sctp_assoc_bh_rcv+0x1f6/0x340
This happens when calling sctp_sendmsg without connecting to server first.
In this case, a data chunk already queues up in send queue of client side
when processing the INIT_ACK from server in sctp_process_init() where it
calls sctp_stream_init() to alloc stream_in. If it fails to alloc stream_in
all stream_out will be freed in sctp_stream_init's err path. Then in the
asoc freeing it will crash when dequeuing this data chunk as stream_out
is missing.
As we can't free stream out before dequeuing all data from send queue, and
this patch is to fix it by moving the err path stream_out/in freeing in
sctp_stream_init() to sctp_stream_free() which is eventually called when
freeing the asoc in sctp_association_free(). This fix also makes the code
in sctp_process_init() more clear.
Note that in sctp_association_init() when it fails in sctp_stream_init(),
sctp_association_free() will not be called, and in that case it should
go to 'stream_free' err path to free stream instead of 'fail_init'.
Fixes: 5bbbbe32a431 ("sctp: introduce stream scheduler foundations")
Reported-by: Wei Chen <harperchen1110@xxxxxxxxx>
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Link: https://lore.kernel.org/r/831a3dc100c4908ff76e5bcc363be97f2778bc0b.1658787066.git.lucien.xin@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index fb6f62264e87..f960b0e1e552 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -224,9 +224,8 @@ static struct sctp_association *sctp_association_init(
if (!sctp_ulpq_init(&asoc->ulpq, asoc))
goto fail_init;
- if (sctp_stream_init(&asoc->stream, asoc->c.sinit_num_ostreams,
- 0, gfp))
- goto fail_init;
+ if (sctp_stream_init(&asoc->stream, asoc->c.sinit_num_ostreams, 0, gfp))
+ goto stream_free;
/* Initialize default path MTU. */
asoc->pathmtu = sp->pathmtu;
diff --git a/net/sctp/stream.c b/net/sctp/stream.c
index cd20638b6151..56762745d6e4 100644
--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -137,7 +137,7 @@ int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
ret = sctp_stream_alloc_out(stream, outcnt, gfp);
if (ret)
- goto out_err;
+ return ret;
for (i = 0; i < stream->outcnt; i++)
SCTP_SO(stream, i)->state = SCTP_STREAM_OPEN;
@@ -145,22 +145,9 @@ int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
handle_in:
sctp_stream_interleave_init(stream);
if (!incnt)
- goto out;
-
- ret = sctp_stream_alloc_in(stream, incnt, gfp);
- if (ret)
- goto in_err;
-
- goto out;
+ return 0;
-in_err:
- sched->free(stream);
- genradix_free(&stream->in);
-out_err:
- genradix_free(&stream->out);
- stream->outcnt = 0;
-out:
- return ret;
+ return sctp_stream_alloc_in(stream, incnt, gfp);
}
int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid)
