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From: Dan Carpenter <dan.carpenter@oracle.com>
To: "Michael S. Tsirkin" <mst@redhat.com>, Jason Wang <jasowang@redhat.com>
Cc: virtualization@lists.linux-foundation.org,
	kernel-janitors@vger.kernel.org
Subject: [PATCH 2/2] vdpa: Fix pointer math bug in vdpasim_get_config()
Date: Mon, 6 Apr 2020 17:45:52 +0300	[thread overview]
Message-ID: <20200406144552.GF68494@mwanda> (raw)
In-Reply-To: <20200406144509.GE68494@mwanda>

If "offset" is non-zero then we end up copying from beyond the end of
the config because of pointer math.  We can fix this by casting the
struct to a u8 pointer.

Fixes: 2c53d0f64c06 ("vdpasim: vDPA device simulator")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
Is it really worth letting people specify the offset?

 drivers/vdpa/vdpa_sim/vdpa_sim.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index b3c800653056..e03c25765513 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -509,7 +509,7 @@ static void vdpasim_get_config(struct vdpa_device *vdpa, unsigned int offset,
 	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 
 	if (offset + len < sizeof(struct virtio_net_config))
-		memcpy(buf, &vdpasim->config + offset, len);
+		memcpy(buf, (u8 *)&vdpasim->config + offset, len);
 }
 
 static void vdpasim_set_config(struct vdpa_device *vdpa, unsigned int offset,
-- 
2.25.1

  reply	other threads:[~2020-04-06 14:45 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-06 14:45 [PATCH 1/2] vdpa: Signedness bugs in vdpasim_work() Dan Carpenter
2020-04-06 14:45 ` Dan Carpenter [this message]
2020-04-09  2:06   ` [PATCH 2/2] vdpa: Fix pointer math bug in vdpasim_get_config() Jason Wang
2020-04-09  2:05 ` [PATCH 1/2] vdpa: Signedness bugs in vdpasim_work() Jason Wang

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