2022-08-31 16:18:21

by Maxime Coquelin

Subject: [PATCH v3] vduse: prevent uninitialized memory accesses

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: [email protected] # v5.15+
Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace")
Reviewed-by: Xie Yongji <[email protected]>
Acked-by: Jason Wang <[email protected]>
Signed-off-by: Maxime Coquelin <[email protected]>
---
drivers/vdpa/vdpa_user/vduse_dev.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 41c0b29739f1..35dceee3ed56 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -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);
}

--
2.37.2

2022-08-31 17:03:10

by Chaitanya Kulkarni

Subject: Re: [PATCH v3] vduse: prevent uninitialized memory accesses

On 8/31/22 08:49, Maxime Coquelin wrote:
> 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: [email protected] # v5.15+
> Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace")
> Reviewed-by: Xie Yongji <[email protected]>
> Acked-by: Jason Wang <[email protected]>
> Signed-off-by: Maxime Coquelin <[email protected]>
> ---

Looks good.

Reviewed-by: Chaitanya Kulkarni <[email protected]>