From: Xin Long lucien.xin@gmail.com
[ 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@gmail.com Signed-off-by: Xin Long lucien.xin@gmail.com Link: https://lore.kernel.org/r/831a3dc100c4908ff76e5bcc363be97f2778bc0b.165878706... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/sctp/associola.c | 5 ++--- net/sctp/stream.c | 19 +++---------------- 2 files changed, 5 insertions(+), 19 deletions(-)
diff --git a/net/sctp/associola.c b/net/sctp/associola.c index be29da09cc7a..3460abceba44 100644 --- a/net/sctp/associola.c +++ b/net/sctp/associola.c @@ -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; diff --git a/net/sctp/stream.c b/net/sctp/stream.c index 6dc95dcc0ff4..ef9fceadef8d 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)