From: Xin Long lucien.xin@gmail.com
[ Upstream commit 02968ccf0125d39b08ecef5946300a8a873c0942 ]
Now sctp increases sk_wmem_alloc by 1 when doing set_owner_w for the skb allocked in sctp_packet_transmit and decreases by 1 when freeing this skb.
But when this skb goes through networking stack, some subcomponents might change skb->truesize and add the same amount on sk_wmem_alloc. However sctp doesn't know the amount to decrease by, it would cause a leak on sk->sk_wmem_alloc and the sock can never be freed.
Xiumei found this issue when it hit esp_output_head() by using sctp over ipsec, where skb->truesize is added and so is sk->sk_wmem_alloc.
Since sctp has used sk_wmem_queued to count for writable space since Commit cd305c74b0f8 ("sctp: use sk_wmem_queued to check for writable space"), it's ok to fix it by counting sk_wmem_alloc by skb truesize in sctp_packet_transmit.
Fixes: cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible") Reported-by: Xiumei Mu xmu@redhat.com Signed-off-by: Xin Long lucien.xin@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/sctp/output.c | 21 +-------------------- 1 file changed, 1 insertion(+), 20 deletions(-)
diff --git a/net/sctp/output.c b/net/sctp/output.c index 08601223b0bfa..b0e74a3e77ec5 100644 --- a/net/sctp/output.c +++ b/net/sctp/output.c @@ -399,25 +399,6 @@ finish: return retval; }
-static void sctp_packet_release_owner(struct sk_buff *skb) -{ - sk_free(skb->sk); -} - -static void sctp_packet_set_owner_w(struct sk_buff *skb, struct sock *sk) -{ - skb_orphan(skb); - skb->sk = sk; - skb->destructor = sctp_packet_release_owner; - - /* - * The data chunks have already been accounted for in sctp_sendmsg(), - * therefore only reserve a single byte to keep socket around until - * the packet has been transmitted. - */ - refcount_inc(&sk->sk_wmem_alloc); -} - static void sctp_packet_gso_append(struct sk_buff *head, struct sk_buff *skb) { if (SCTP_OUTPUT_CB(head)->last == head) @@ -604,7 +585,7 @@ int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp) if (!head) goto out; skb_reserve(head, packet->overhead + MAX_HEADER); - sctp_packet_set_owner_w(head, sk); + skb_set_owner_w(head, sk);
/* set sctp header */ sh = skb_push(head, sizeof(struct sctphdr));