[PATCH v1] staging: rtl8723bs: fix stale recv_frame free in recv_func_posthandle()

[Yuho Choi]

recv_func_posthandle() saved the original recv_frame pointer before
calling recvframe_chk_defrag().

On the last-fragment reassembly path, recvframe_chk_defrag() may return
the first fragment as the new frame while freeing the original
last-fragment frame when draining the defrag queue.

If process_recv_indicatepkts() then fails, recv_func_posthandle() frees
the saved pre-defrag pointer again, which can result in a stale pointer
free.

Free the current recv_frame on the failure path instead of the saved
pre-defrag pointer.

Fixes: 554c0a3abf21 ("staging: Add rtl8723bs sdio wifi driver")
Co-developed-by: Myeonghun Pak <mhun512@xxxxxxxxx>
Signed-off-by: Myeonghun Pak <mhun512@xxxxxxxxx>
Co-developed-by: Ijae Kim <ae878000@xxxxxxxxx>
Signed-off-by: Ijae Kim <ae878000@xxxxxxxxx>
Co-developed-by: Taegyu Kim <tmk5904@xxxxxxx>
Signed-off-by: Taegyu Kim <tmk5904@xxxxxxx>
Signed-off-by: Yuho Choi <dbgh9129@xxxxxxxxx>
---
 drivers/staging/rtl8723bs/core/rtw_recv.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/staging/rtl8723bs/core/rtw_recv.c b/drivers/staging/rtl8723bs/core/rtw_recv.c
index 337671b1211f0..a404b6fc97723 100644
--- a/drivers/staging/rtl8723bs/core/rtw_recv.c
+++ b/drivers/staging/rtl8723bs/core/rtw_recv.c
@@ -2139,7 +2139,6 @@ static int recv_func_prehandle(struct adapter *padapter, union recv_frame *rfram
 static int recv_func_posthandle(struct adapter *padapter, union recv_frame *prframe)
 {
 	int ret = _SUCCESS;
-	union recv_frame *orig_prframe = prframe;
 	struct recv_priv *precvpriv = &padapter->recvpriv;
 	struct __queue *pfree_recv_queue = &padapter->recvpriv.free_recv_queue;
 
@@ -2163,7 +2162,7 @@ static int recv_func_posthandle(struct adapter *padapter, union recv_frame *prfr
 
 	ret = process_recv_indicatepkts(padapter, prframe);
 	if (ret != _SUCCESS) {
-		rtw_free_recvframe(orig_prframe, pfree_recv_queue);/* free this recv_frame */
+		rtw_free_recvframe(prframe, pfree_recv_queue);/* free this recv_frame */
 		goto _recv_data_drop;
 	}
 
-- 
2.50.1 (Apple Git-155)