[PATCH v2 2/4] staging: rtl8723bs: fix double free when register_netdev() fails

[Yi Cong]

From: Yi Cong <yicong@xxxxxxxxxx>

When register_netdev() fails, the error_register_netdev label in
_rtw_drv_register_netdev() frees the adapter and netdev via
rtw_free_drv_sw()/rtw_free_netdev() and then returns _FAIL.

The caller rtw_drv_init(), however, still holds a non-NULL if1 on this
failure path and jumps to free_if1, where rtw_sdio_if1_deinit() invokes
rtw_free_drv_sw() and rtw_free_netdev() again on the same already-freed
objects, resulting in a double free / use-after-free.

Drop the freeing from error_register_netdev and let rtw_sdio_if1_deinit()
perform the tear-down, which is the single owner for this path.

Fixes: 554c0a3abf21 ("staging: Add rtl8723bs sdio wifi driver")
Signed-off-by: Yi Cong <yicong@xxxxxxxxxx>
---
 drivers/staging/rtl8723bs/os_dep/os_intfs.c | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/drivers/staging/rtl8723bs/os_dep/os_intfs.c b/drivers/staging/rtl8723bs/os_dep/os_intfs.c
index f31196f54b3e0..84633a51e2db7 100644
--- a/drivers/staging/rtl8723bs/os_dep/os_intfs.c
+++ b/drivers/staging/rtl8723bs/os_dep/os_intfs.c
@@ -754,7 +754,6 @@ u8 rtw_free_drv_sw(struct adapter *padapter)
 
 static int _rtw_drv_register_netdev(struct adapter *padapter, char *name)
 {
-	int ret = _SUCCESS;
 	struct net_device *pnetdev = padapter->pnetdev;
 
 	/* alloc netdev name */
@@ -765,19 +764,10 @@ static int _rtw_drv_register_netdev(struct adapter *padapter, char *name)
 
 	/* Tell the network stack we exist */
 	if (register_netdev(pnetdev) != 0) {
-		ret = _FAIL;
-		goto error_register_netdev;
+		return _FAIL;
 	}
 
-	return ret;
-
-error_register_netdev:
-
-	rtw_free_drv_sw(padapter);
-
-	rtw_free_netdev(pnetdev);
-
-	return ret;
+	return _SUCCESS;
 }
 
 int rtw_drv_register_netdev(struct adapter *if1)
-- 
2.25.1