[PATCH] staging: rtl8192e: rtl_core: Fix possible null-pointer dereference in _rtl92e_pci_disconnect()

[PATCH] staging: rtl8192e: rtl_core: Fix possible null-pointer dereference in _rtl92e_pci_disconnect()

[Tuo Li]

The variable dev is checked in:
  if (dev)

This indicates that it can be NULL. If so, a null-pointer dereference will 
occur:
  priv = rtllib_priv(dev);

However, the value of priv is not used in the remaining part of this 
function. Thus the else-branch can be removed to fix this posible 
null-pointer dereference.

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Tuo Li <islituo@gmail.com>
---
 drivers/staging/rtl8192e/rtl8192e/rtl_core.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/staging/rtl8192e/rtl8192e/rtl_core.c b/drivers/staging/rtl8192e/rtl8192e/rtl_core.c
index e85d9c2cdc96..0eb37a95b519 100644
--- a/drivers/staging/rtl8192e/rtl8192e/rtl_core.c
+++ b/drivers/staging/rtl8192e/rtl8192e/rtl_core.c
@@ -2557,8 +2557,6 @@ static void _rtl92e_pci_disconnect(struct pci_dev *pdev)
 			release_mem_region(pci_resource_start(pdev, 1),
 					pci_resource_len(pdev, 1));
 		}
-	} else {
-		priv = rtllib_priv(dev);
 	}
 
 	pci_disable_device(pdev);
-- 
2.25.1

Re: [PATCH] staging: rtl8192e: rtl_core: Fix possible null-pointer dereference in _rtl92e_pci_disconnect()

[Dan Carpenter]

On Tue, Aug 10, 2021 at 08:11:35PM -0700, Tuo Li wrote:
> The variable dev is checked in:
>   if (dev)
> 
> This indicates that it can be NULL. If so, a null-pointer dereference will 
> occur:
>   priv = rtllib_priv(dev);
> 
> However, the value of priv is not used in the remaining part of this 
> function. Thus the else-branch can be removed to fix this posible 
> null-pointer dereference.
> 
> Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
> Signed-off-by: Tuo Li <islituo@gmail.com>

Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>

Smatch was not smart enough to spot the dereference inside rtllib_priv().
Fortunately, the "dev" variable can't be NULL at this point.

regards,
dan carpenter