4.9-stable review patch. If anyone has any objections, please let me know.
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From: Xin Long lucien.xin@gmail.com
[ Upstream commit 6910e25de2257e2c82c7a2d126e3463cd8e50810 ]
In Commit 1f45f78f8e51 ("sctp: allow GSO frags to access the chunk too"), it held the chunk in sctp_ulpevent_make_rcvmsg to access it safely later in recvmsg. However, it also added sctp_chunk_put in fail_mark err path, which is only triggered before holding the chunk.
syzbot reported a use-after-free crash happened on this err path, where it shouldn't call sctp_chunk_put.
This patch simply removes this call.
Fixes: 1f45f78f8e51 ("sctp: allow GSO frags to access the chunk too") Reported-by: syzbot+141d898c5f24489db4aa@syzkaller.appspotmail.com Signed-off-by: Xin Long lucien.xin@gmail.com Acked-by: Neil Horman nhorman@tuxdriver.com Acked-by: Marcelo Ricardo Leitner marcelo.leitner@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sctp/ulpevent.c | 1 - 1 file changed, 1 deletion(-)
--- a/net/sctp/ulpevent.c +++ b/net/sctp/ulpevent.c @@ -723,7 +723,6 @@ struct sctp_ulpevent *sctp_ulpevent_make return event;
fail_mark: - sctp_chunk_put(chunk); kfree_skb(skb); fail: return NULL;