| Message ID | 20240212082202.17927-1-dmantipov@yandex.ru (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v2] net: sctp: fix skb leak in sctp_inq_free() | expand |
On Mon, 12 Feb 2024 11:22:02 +0300 Dmitry Antipov wrote: > 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_chunk_release()' 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. Please repost this as a separate thread, per: https://www.kernel.org/doc/html/next/process/maintainer-netdev.html#resending-after-review Xin Long is probably out for New Year celebrations, anyway.
On Mon, Feb 12, 2024 at 7:25 PM Jakub Kicinski <kuba@kernel.org> wrote: > > On Mon, 12 Feb 2024 11:22:02 +0300 Dmitry Antipov wrote: > > 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_chunk_release()' 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. > > Please repost this as a separate thread, per: > https://www.kernel.org/doc/html/next/process/maintainer-netdev.html#resending-after-review and instead of sctp_chunk_release(), please use a better name like "sctp_inq_chunk_free()" when you repost. Thanks. > Xin Long is probably out for New Year celebrations, anyway. > -- > pw-bot: cr
diff --git a/net/sctp/inqueue.c b/net/sctp/inqueue.c index 7182c5a450fb..9ec172405ff4 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_chunk_release(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_chunk_release(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_chunk_release(chunk); chunk = queue->in_progress = NULL; } else { /* Nothing to do. Next chunk in the packet, please. */
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_chunk_release()' 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: 90017accff61 ("sctp: Add GSO support") Suggested-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> --- v2: factor the fix out to helper function (Jakub Kicinski) --- net/sctp/inqueue.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)