Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Colin King <colin.king@canonical.com>
To:     Potnuri Bharat Teja <bharat@chelsio.com>,
        Doug Ledford <dledford@redhat.com>,
        Jason Gunthorpe <jgg@ziepe.ca>, linux-rdma@vger.kernel.org
Cc:     kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] RDMA/cxgb4: fix null pointer dereference on alloc_skb failure
Date:   Sat, 13 Apr 2019 17:00:26 +0100
Message-Id: <20190413160026.5873-1-colin.king@canonical.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Colin Ian King <colin.king@canonical.com>

Currently if alloc_skb fails to allocate the skb a null skb is passed
to t4_set_arp_err_handler and this ends up dereferencing the null skb.
Avoid the null pointer dereference by checking for a null skb and
returning early.

Addresses-Coverity: ("Dereference null return")
Fixes: b38a0ad8ec11 ("RDMA/cxgb4: Set arp error handler for PASS_ACCEPT_RPL messages")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/infiniband/hw/cxgb4/cm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/infiniband/hw/cxgb4/cm.c b/drivers/infiniband/hw/cxgb4/cm.c
index 1e68d87b663d..0f3b1193d5f8 100644
--- a/drivers/infiniband/hw/cxgb4/cm.c
+++ b/drivers/infiniband/hw/cxgb4/cm.c
@@ -460,6 +460,8 @@ static struct sk_buff *get_skb(struct sk_buff *skb, int len, gfp_t gfp)
 		skb_reset_transport_header(skb);
 	} else {
 		skb = alloc_skb(len, gfp);
+		if (!skb)
+			return NULL;
 	}
 	t4_set_arp_err_handler(skb, NULL, NULL);
 	return skb;
-- 
2.20.1