From: Maxime Coquelin maxime.coquelin@redhat.com
commit 46f8a29272e51b6df7393d58fc5cb8967397ef2b upstream.
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 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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/vdpa/vdpa_user/vduse_dev.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
--- a/drivers/vdpa/vdpa_user/vduse_dev.c +++ b/drivers/vdpa/vdpa_user/vduse_dev.c @@ -655,10 +655,15 @@ static void vduse_vdpa_get_config(struct { 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); }