[PATCH 3.12 138/142] intel_scu_ipcutil: underflow in scu_reg_access()

[Jiri Slaby]

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit b1d353ad3d5835b16724653b33c05124e1b5acf1 upstream.

"count" is controlled by the user and it can be negative.  Let's prevent
that by making it unsigned.  You have to have CAP_SYS_RAWIO to call this
function so the bug is not as serious as it could be.

Fixes: 5369c02d951a ('intel_scu_ipc: Utility driver for intel scu ipc')
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Darren Hart <dvhart@xxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 drivers/platform/x86/intel_scu_ipcutil.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/platform/x86/intel_scu_ipcutil.c b/drivers/platform/x86/intel_scu_ipcutil.c
index 02bc5a6343c3..aa454241489c 100644
--- a/drivers/platform/x86/intel_scu_ipcutil.c
+++ b/drivers/platform/x86/intel_scu_ipcutil.c
@@ -49,7 +49,7 @@ struct scu_ipc_data {
 
 static int scu_reg_access(u32 cmd, struct scu_ipc_data  *data)
 {
-	int count = data->count;
+	unsigned int count = data->count;
 
 	if (count == 0 || count == 3 || count > 4)
 		return -EINVAL;
-- 
2.7.1