Commit 4e45170d authored by Dmitry Antipov's avatar Dmitry Antipov Committed by Jakub Kicinski
Browse files

net: sctp: fix skb leak in sctp_inq_free() 



In case of GSO, 'chunk->skb' pointer may point to an entry from
fraglist created in 'sctp_packet_gso_append()'. To avoid freeing
random fraglist entry (and so undefined behavior and/or memory
leak), introduce 'sctp_inq_chunk_free()' helper to ensure that
'chunk->skb' is set to 'chunk->head_skb' (i.e. fraglist head)
before calling 'sctp_chunk_free()', and use the aforementioned
helper in 'sctp_inq_pop()' as well.

Reported-by: default avatar <syzbot+8bb053b5d63595ab47db@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?id=0d8351bbe54fd04a492c2daab0164138db008042


Fixes: 90017acc ("sctp: Add GSO support")
Suggested-by: default avatarXin Long <lucien.xin@gmail.com>
Signed-off-by: default avatarDmitry Antipov <dmantipov@yandex.ru>
Acked-by: default avatarXin Long <lucien.xin@gmail.com>
Link: https://lore.kernel.org/r/20240214082224.10168-1-dmantipov@yandex.ru


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent e5b2e810

net/sctp/inqueue.c

+10 −4
Original line number Diff line number Diff line
@@ -38,6 +38,14 @@ void sctp_inq_init(struct sctp_inq *queue) 
	INIT_WORK(&queue->immediate, NULL);

}



/* Properly release the chunk which is being worked on. */

static inline void sctp_inq_chunk_free(struct sctp_chunk *chunk)

{

	if (chunk->head_skb)

		chunk->skb = chunk->head_skb;

	sctp_chunk_free(chunk);

}



/* Release the memory associated with an SCTP inqueue.  */

void sctp_inq_free(struct sctp_inq *queue)

{
@@ -53,7 +61,7 @@ void sctp_inq_free(struct sctp_inq *queue) 
	 * free it as well.

	 */

	if (queue->in_progress) {

		sctp_chunk_free(queue->in_progress);

		sctp_inq_chunk_free(queue->in_progress);

		queue->in_progress = NULL;

	}

}
@@ -130,9 +138,7 @@ struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue) 
				goto new_skb;

			}



			if (chunk->head_skb)

				chunk->skb = chunk->head_skb;

			sctp_chunk_free(chunk);

			sctp_inq_chunk_free(chunk);

			chunk = queue->in_progress = NULL;

		} else {

			/* Nothing to do. Next chunk in the packet, please. */