[PATCH v2] vduse: Validate vq_num in vduse_validate_config()

[Harshit Mogalapalli]

Add a limit to 'config->vq_num' which is user controlled data which
comes from an vduse_ioctl to prevent large memory allocations.

This is found using static analysis with smatch.

Suggested-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>
---
v1->v2: Change title of the commit and description, add a limit to
	vq_num.

Note: I think here 0xffff is the max size of vring =  no: of vqueues.
Only compile and boot tested.
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 35dceee3ed56..31017ebc4d7c 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -1440,6 +1440,9 @@ static bool vduse_validate_config(struct vduse_dev_config *config)
 	if (config->config_size > PAGE_SIZE)
 		return false;
 
+	if (config->vq_num > 0xffff)
+		return false;
+
 	if (!device_is_allowed(config->device_id))
 		return false;
 
-- 
2.38.1