Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754576AbcDRChd (ORCPT ); Sun, 17 Apr 2016 22:37:33 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:36605 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752194AbcDRChb (ORCPT ); Sun, 17 Apr 2016 22:37:31 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Arnd Bergmann , "David S. Miller" Subject: [PATCH 4.4 058/137] farsync: fix off-by-one bug in fst_add_one Date: Mon, 18 Apr 2016 11:28:40 +0900 Message-Id: <20160418022511.091381711@linuxfoundation.org> X-Mailer: git-send-email 2.8.0 In-Reply-To: <20160418022507.236379264@linuxfoundation.org> References: <20160418022507.236379264@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2417 Lines: 54 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann [ Upstream commit e725a66c0202b5f36c2f9d59d26a65c53bbf21f7 ] 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: Greg Kroah-Hartman --- 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;