From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Fri, 1 Jun 2018 10:59:25 +0300
Subject: crypto: chtls - use after free in chtls_pt_recvmsg()
Patch-mainline: v4.18-rc2
Git-commit: f70b359b3830b7a5b72c78136edc740839b67acd
References: bsc#1104270 FATE#325931

We call chtls_free_skb() but then we dereference it on the next lines.
Also "skb" can't be NULL, we just dereferenced it on the line before.

I have moved the free down a couple lines to fix this issue.

Fixes: 17a7d24aa89d ("crypto: chtls - generic handling of data and hdr")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/crypto/chelsio/chtls/chtls_io.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--- a/drivers/crypto/chelsio/chtls/chtls_io.c
+++ b/drivers/crypto/chelsio/chtls/chtls_io.c
@@ -1548,15 +1548,14 @@ skip_copy:
 			tp->urg_data = 0;
 
 		if ((avail + offset) >= skb->len) {
-			if (likely(skb))
-				chtls_free_skb(sk, skb);
-			buffers_freed++;
 			if (ULP_SKB_CB(skb)->flags & ULPCB_FLAG_TLS_HDR) {
 				tp->copied_seq += skb->len;
 				hws->rcvpld = skb->hdr_len;
 			} else {
 				tp->copied_seq += hws->rcvpld;
 			}
+			chtls_free_skb(sk, skb);
+			buffers_freed++;
 			hws->copied_seq = 0;
 			if (copied >= target &&
 			    !skb_peek(&sk->sk_receive_queue))