linux-kernel - [PATCH 1/2] um: vector: Fix a potential NULL pointer dereference in 'vector_net

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Message-Id: <20181226075436.11018-1-christophe.jaillet@wanadoo.fr>
Date:   Wed, 26 Dec 2018 08:54:36 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     jdike@...toit.com, richard@....at, anton.ivanov@...bridgegreys.com,
        rppt@...ux.vnet.ibm.com, akpm@...ux-foundation.org,
        yuehaibing@...wei.com, keescook@...omium.org
Cc:     linux-um@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: [PATCH 1/2] um: vector: Fix a potential NULL pointer dereference in 'vector_net_open()'

'create_queue()' returns NULL in case of memory allocation failure. So we
must check if it succeeds in order to avoid potential NULL pointer
dereference.

For 'vp->rx_queue', the dereference would occur just one line after the
failed allocation. For 'vp->tx_queue', it would occur later during normal
processing.

Fixes: 49da7e64f33e ("High Performance UML Vector Network Driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
 arch/um/drivers/vector_kern.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/um/drivers/vector_kern.c b/arch/um/drivers/vector_kern.c
index 046fa9ea0ccc..5b917716289d 100644
--- a/arch/um/drivers/vector_kern.c
+++ b/arch/um/drivers/vector_kern.c
@@ -1182,6 +1182,8 @@ static int vector_net_open(struct net_device *dev)
 			vp->rx_header_size,
 			MAX_IOV_SIZE
 		);
+		if (!vp->rx_queue)
+			goto out_close;
 		vp->rx_queue->queue_depth = get_depth(vp->parsed);
 	} else {
 		vp->header_rxbuffer = kmalloc(
@@ -1198,6 +1200,8 @@ static int vector_net_open(struct net_device *dev)
 			vp->header_size,
 			MAX_IOV_SIZE
 		);
+		if (!vp->tx_queue)
+			goto out_close;
 	} else {
 		vp->header_txbuffer = kmalloc(vp->header_size, GFP_KERNEL);
 		if (vp->header_txbuffer == NULL)
-- 
2.19.1