Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754689AbcD0AWo (ORCPT ); Tue, 26 Apr 2016 20:22:44 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:39970 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753889AbcDZXNv (ORCPT ); Tue, 26 Apr 2016 19:13:51 -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" , "David S. Miller" Date: Wed, 27 Apr 2016 01:02:21 +0200 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 205/217] farsync: fix off-by-one bug in fst_add_one In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8426:ae4:c500:9cba:69ae:962d:6167 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 Content-Length: 2399 Lines: 53 3.16.35-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann commit e725a66c0202b5f36c2f9d59d26a65c53bbf21f7 upstream. gcc-6 finds an out of bounds access in the fst_add_one function when calculating the end of the mmio area: drivers/net/wan/farsync.c: In function 'fst_add_one': drivers/net/wan/farsync.c:418:53: error: index 2 denotes an offset greater than size of 'u8[2][8192] {aka unsigned char[2][8192]}' [-Werror=array-bounds] #define BUF_OFFSET(X) (BFM_BASE + offsetof(struct buf_window, X)) ^ include/linux/compiler-gcc.h:158:21: note: in definition of macro '__compiler_offsetof' __builtin_offsetof(a, b) ^ drivers/net/wan/farsync.c:418:37: note: in expansion of macro 'offsetof' #define BUF_OFFSET(X) (BFM_BASE + offsetof(struct buf_window, X)) ^~~~~~~~ drivers/net/wan/farsync.c:2519:36: note: in expansion of macro 'BUF_OFFSET' + BUF_OFFSET ( txBuffer[i][NUM_TX_BUFFER][0]); ^~~~~~~~~~ The warning is correct, but not critical because this appears to be a write-only variable that is set by each WAN driver but never accessed afterwards. I'm taking the minimal fix here, using the correct pointer by pointing 'mem_end' to the last byte inside of the register area as all other WAN drivers do, rather than the first byte outside of it. An alternative would be to just remove the mem_end member entirely. Signed-off-by: Arnd Bergmann Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- drivers/net/wan/farsync.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/net/wan/farsync.c +++ b/drivers/net/wan/farsync.c @@ -2516,7 +2516,7 @@ fst_add_one(struct pci_dev *pdev, const dev->mem_start = card->phys_mem + BUF_OFFSET ( txBuffer[i][0][0]); dev->mem_end = card->phys_mem - + BUF_OFFSET ( txBuffer[i][NUM_TX_BUFFER][0]); + + BUF_OFFSET ( txBuffer[i][NUM_TX_BUFFER - 1][LEN_RX_BUFFER - 1]); dev->base_addr = card->pci_conf; dev->irq = card->irq;