From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752583AbdFAQWV (ORCPT ); Thu, 1 Jun 2017 12:22:21 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33201 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752054AbdFAPov (ORCPT ); Thu, 1 Jun 2017 11:44:51 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Arnd Bergmann" , "Greg Kroah-Hartman" Date: Thu, 01 Jun 2017 16:43:15 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 053/212] staging: rtl: fix possible NULL pointer dereference In-Reply-To: X-SA-Exim-Connect-IP: 82.70.136.246 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.44-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann commit 6e017006022abfea5d2466cad936065f45763ad1 upstream. gcc-7 detects that wlanhdr_to_ethhdr() in two drivers calls memcpy() with a destination argument that an earlier function call may have set to NULL: staging/rtl8188eu/core/rtw_recv.c: In function 'wlanhdr_to_ethhdr': staging/rtl8188eu/core/rtw_recv.c:1318:2: warning: argument 1 null where non-null expected [-Wnonnull] staging/rtl8712/rtl871x_recv.c: In function 'r8712_wlanhdr_to_ethhdr': staging/rtl8712/rtl871x_recv.c:649:2: warning: argument 1 null where non-null expected [-Wnonnull] I'm fixing this by adding a NULL pointer check and returning failure from the function, which is hopefully already handled properly. This seems to date back to when the drivers were originally added, so backporting the fix to stable seems appropriate. There are other related realtek drivers in the kernel, but none of them contain a function with a similar name or produce this warning. Fixes: 1cc18a22b96b ("staging: r8188eu: Add files for new driver - part 5") Fixes: 2865d42c78a9 ("staging: r8712u: Add the new driver to the mainline kernel") Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- --- a/drivers/staging/rtl8188eu/core/rtw_recv.c +++ b/drivers/staging/rtl8188eu/core/rtw_recv.c @@ -1419,10 +1419,14 @@ static int wlanhdr_to_ethhdr(struct recv eth_type = 0x8712; /* append rx status for mp test packets */ ptr = recvframe_pull(precvframe, (rmv_len-sizeof(struct ethhdr)+2)-24); + if (!ptr) + return _FAIL; memcpy(ptr, get_rxmem(precvframe), 24); ptr += 24; } else { ptr = recvframe_pull(precvframe, (rmv_len-sizeof(struct ethhdr) + (bsnaphdr ? 2 : 0))); + if (!ptr) + return _FAIL; } memcpy(ptr, pattrib->dst, ETH_ALEN); --- a/drivers/staging/rtl8712/rtl871x_recv.c +++ b/drivers/staging/rtl8712/rtl871x_recv.c @@ -639,11 +639,16 @@ sint r8712_wlanhdr_to_ethhdr(union recv_ /* append rx status for mp test packets */ ptr = recvframe_pull(precvframe, (rmv_len - sizeof(struct ethhdr) + 2) - 24); + if (!ptr) + return _FAIL; memcpy(ptr, get_rxmem(precvframe), 24); ptr += 24; - } else + } else { ptr = recvframe_pull(precvframe, (rmv_len - sizeof(struct ethhdr) + (bsnaphdr ? 2 : 0))); + if (!ptr) + return _FAIL; + } memcpy(ptr, pattrib->dst, ETH_ALEN); memcpy(ptr+ETH_ALEN, pattrib->src, ETH_ALEN);