Patchwork crypto: chtls - use after free in chtls_pt_recvmsg()

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Submitter Dan Carpenter
Date June 1, 2018, 7:59 a.m.
Message ID <20180601075852.fn5hongkasesi2ep@kili.mountain>
Download mbox | patch
Permalink /patch/10442631/
State Accepted
Delegated to: Herbert Xu
Headers show

Comments

Dan Carpenter - June 1, 2018, 7:59 a.m.
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>
Herbert Xu - June 15, 2018, 3:13 p.m.
On Fri, Jun 01, 2018 at 10:59:25AM +0300, Dan Carpenter wrote:
> 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>

Patch applied.  Thanks.

Patch

diff --git a/drivers/crypto/chelsio/chtls/chtls_io.c b/drivers/crypto/chelsio/chtls/chtls_io.c
index 51fc6821cbbf..708e232e3cdf 100644
--- a/drivers/crypto/chelsio/chtls/chtls_io.c
+++ b/drivers/crypto/chelsio/chtls/chtls_io.c
@@ -1548,15 +1548,14 @@  static int chtls_pt_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 			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))