This is a note to let you know that I've just added the patch titled
net: sctp: fix skb leak in sctp_inq_free()
to the 6.1-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:
net-sctp-fix-skb-leak-in-sctp_inq_free.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 46fa42f00af85de45310a2b2d92096d1c21a1ad6
Author: Dmitry Antipov <dmantipov@xxxxxxxxx>
Date: Wed Feb 14 11:22:24 2024 +0300
net: sctp: fix skb leak in sctp_inq_free()
[ Upstream commit 4e45170d9acc2d5ae8f545bf3f2f67504a361338 ]
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: syzbot+8bb053b5d63595ab47db@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?id=0d8351bbe54fd04a492c2daab0164138db008042
Fixes: 90017accff61 ("sctp: Add GSO support")
Suggested-by: Xin Long <lucien.xin@xxxxxxxxx>
Signed-off-by: Dmitry Antipov <dmantipov@xxxxxxxxx>
Acked-by: Xin Long <lucien.xin@xxxxxxxxx>
Link: https://lore.kernel.org/r/20240214082224.10168-1-dmantipov@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/sctp/inqueue.c b/net/sctp/inqueue.c
index 7182c5a450fb5..5c16521818058 100644
--- a/net/sctp/inqueue.c
+++ b/net/sctp/inqueue.c
@@ -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. */
