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sctp: leave the err path free in sctp_stream_init to sctp_stream_free 

[ Upstream commit 181d8d2066 ]

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: 5bbbbe32a4 ("sctp: introduce stream scheduler foundations")
Reported-by: Wei Chen <harperchen1110@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Link: https://lore.kernel.org/r/831a3dc100c4908ff76e5bcc363be97f2778bc0b.1658787066.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Xin Long 2022-07-25 18:11:06 -04:00 committed by Greg Kroah-Hartman
parent 39e03b53a1
commit d99f144acc
2 changed files with 5 additions and 19 deletions
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5
net/sctp/associola.c
View File

@ -229,9 +229,8 @@ 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;

19
net/sctp/stream.c
View File

@ -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;
return 0;
ret = sctp_stream_alloc_in(stream, incnt, gfp);
if (ret)
goto in_err;
goto out;
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)