rdma/cxgb4: Prevent potential integer overflow on 32bit

JIRA: https://issues.redhat.com/browse/RHEL-83218

commit bd96a39
Author: Dan Carpenter <dan.carpenter@linaro.org>
Date:   Sat Nov 30 13:01:37 2024 +0300

    rdma/cxgb4: Prevent potential integer overflow on 32bit

    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: 1cab775 ("RDMA/cxgb4: Fix LE hash collision bug for passive open connection")
    Link: https://patch.msgid.link/r/86b404e1-4a75-4a35-a34e-e3054fa554c7@stanley.mountain
    Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
    Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

Signed-off-by: Kamal Heib <kheib@redhat.com>

Author: Kamalheib

drivers/infiniband/hw/cxgb4/device.c

@@ -1114,8 +1114,10 @@ static inline struct sk_buff *copy_gl_to_skb_pkt(const struct pkt_gl *gl,
 	 * The math here assumes sizeof cpl_pass_accept_req >= sizeof
 	 * cpl_rx_pkt.
 	 */
-	skb = alloc_skb(gl->tot_len + sizeof(struct cpl_pass_accept_req) +
-			sizeof(struct rss_header) - pktshift, GFP_ATOMIC);
+	skb = alloc_skb(size_add(gl->tot_len,
+				 sizeof(struct cpl_pass_accept_req) +
+				 sizeof(struct rss_header)) - pktshift,
+			GFP_ATOMIC);
 	if (unlikely(!skb))
 		return NULL;