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: c8a6153b6c59 ("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 --- 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); }