From: Dan Carpenter <dan.carpen...@oracle.com>

[ Upstream commit cf16fe9243bfa2863491026fc727618c7c593c84 ]

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.carpen...@oracle.com>
Link: https://lore.kernel.org/r/20200406144552.GF68494@mwanda
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
Acked-by: Jason Wang <jasow...@redhat.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 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 412fa85ba3653..67956db75013f 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -522,7 +522,7 @@ 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



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