[PATCH net] chelsio/chtls: prevent potential integer overflow on 32bit

[Dan Carpenter]

The "gl->tot_len" variable is controlled by the user.  It comes from
process_responses().  On 32bit systems, the "gl->tot_len +
sizeof(struct cpl_pass_accept_req) + sizeof(struct rss_header)" addition
could have an integer wrapping bug.  Use size_add() to prevent this.

Fixes: a08943947873 ("crypto: chtls - Register chtls with net tls")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
I fixed a similar bug earlier:
https://lore.kernel.org/all/86b404e1-4a75-4a35-a34e-e3054fa554c7@stanley.mountain

 .../net/ethernet/chelsio/inline_crypto/chtls/chtls_main.c    | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_main.c b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_main.c
index 96fd31d75dfd..daa1ebaef511 100644
--- a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_main.c
+++ b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_main.c
@@ -346,8 +346,9 @@ static struct sk_buff *copy_gl_to_skb_pkt(const struct pkt_gl *gl,
 	 * driver. Once driver synthesizes cpl_pass_accept_req the skb will go
 	 * through the regular cpl_pass_accept_req processing in TOM.
 	 */
-	skb = alloc_skb(gl->tot_len + sizeof(struct cpl_pass_accept_req)
-			- pktshift, GFP_ATOMIC);
+	skb = alloc_skb(size_add(gl->tot_len,
+				 sizeof(struct cpl_pass_accept_req)) -
+			pktshift, GFP_ATOMIC);
 	if (unlikely(!skb))
 		return NULL;
 	__skb_put(skb, gl->tot_len + sizeof(struct cpl_pass_accept_req)
-- 
2.45.2