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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: syzbot+8bb053b5d63595ab47db@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?id=0d8351bbe54fd04a492c2daab0164138db008042
Fixes: 90017accff ("sctp: Add GSO support")
Suggested-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Acked-by: Xin Long <lucien.xin@gmail.com>
Link: https://lore.kernel.org/r/20240214082224.10168-1-dmantipov@yandex.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Dmitry Antipov 2024-02-14 11:22:24 +03:00 committed by Jakub Kicinski
parent e5b2e810da
commit 4e45170d9a
1 changed files with 10 additions and 4 deletions
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14
net/sctp/inqueue.c
View File

@ -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. */