If copy_struct_from_user() fails at the start of the function then this
function calls put_user(rsp.length, &r->response.length) before
"rsp.length" is set to zero. That is a potential security issue because
it discloses kernel stack data to user space.
Fixes: 178f6ab77e61 ("platform/surface: Add Surface Aggregator user-space interface")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
drivers/platform/surface/surface_aggregator_cdev.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/platform/surface/surface_aggregator_cdev.c b/drivers/platform/surface/surface_aggregator_cdev.c
index 340d15b148b9..05e9eb118d76 100644
--- a/drivers/platform/surface/surface_aggregator_cdev.c
+++ b/drivers/platform/surface/surface_aggregator_cdev.c
@@ -67,7 +67,7 @@ static long ssam_cdev_request(struct ssam_cdev *cdev, unsigned long arg)
struct ssam_cdev_request __user *r;
struct ssam_cdev_request rqst;
struct ssam_request spec;
- struct ssam_response rsp;
+ struct ssam_response rsp = {};
const void __user *plddata;
void __user *rspdata;
int status = 0, ret = 0, tmp;
@@ -96,8 +96,6 @@ static long ssam_cdev_request(struct ssam_cdev *cdev, unsigned long arg)
spec.flags |= SSAM_REQUEST_UNSEQUENCED;
rsp.capacity = rqst.response.length;
- rsp.length = 0;
- rsp.pointer = NULL;
/* Get request payload from user-space. */
if (spec.length) {
--
2.29.2
