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vduse: prevent uninitialized memory accesses

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If the VDUSE application provides a smaller config space
than the driver expects, the driver may use uninitialized
memory from the stack.

This patch prevents it by initializing the buffer passed by
the driver to store the config value.

This fix addresses CVE-2022-2308.

Cc: stable@vger.kernel.org # v5.15+
Fixes: c8a6153b6c ("vduse: Introduce VDUSE - vDPA Device in Userspace")
Reviewed-by: Xie Yongji <xieyongji@bytedance.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Message-Id: <20220831154923.97809-1-maxime.coquelin@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
This commit is contained in:
Maxime Coquelin 2022-08-31 17:49:23 +02:00 committed by Michael S. Tsirkin
parent 37fafe6b61
commit 46f8a29272
1 changed files with 7 additions and 2 deletions
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9
drivers/vdpa/vdpa_user/vduse_dev.c
View File

@ -673,10 +673,15 @@ static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset,
{
struct vduse_dev *dev = vdpa_to_vduse(vdpa);
if (offset > dev->config_size ||
len > dev->config_size - offset)
/* Initialize the buffer in case of partial copy. */
memset(buf, 0, len);
if (offset > dev->config_size)
return;
if (len > dev->config_size - offset)
len = dev->config_size - offset;
memcpy(buf, dev->config + offset, len);
}