From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754410Ab2LJQZk (ORCPT ); Mon, 10 Dec 2012 11:25:40 -0500 Received: from opensource.wolfsonmicro.com ([80.75.67.52]:47776 "EHLO opensource.wolfsonmicro.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753460Ab2LJQZk (ORCPT ); Mon, 10 Dec 2012 11:25:40 -0500 From: Mark Brown To: linux-kernel@vger.kernel.org Cc: Mark Brown Subject: [PATCH 1/3] regmap: debugfs: Avoid overflows for very small reads Date: Tue, 11 Dec 2012 01:25:30 +0900 Message-Id: <1355156732-2943-1-git-send-email-broonie@opensource.wolfsonmicro.com> X-Mailer: git-send-email 1.7.10.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If count is less than the size of a register then we may hit integer wraparound when trying to move backwards to check if we're still in the buffer. Instead move the position forwards to check if it's still in the buffer, we are unlikely to be able to allocate a buffer sufficiently big to overflow here. Signed-off-by: Mark Brown --- drivers/base/regmap/regmap-debugfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c index 00fbd58..3df274e 100644 --- a/drivers/base/regmap/regmap-debugfs.c +++ b/drivers/base/regmap/regmap-debugfs.c @@ -93,7 +93,7 @@ static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from, /* If we're in the region the user is trying to read */ if (p >= *ppos) { /* ...but not beyond it */ - if (buf_pos >= count - 1 - map->debugfs_tot_len) + if (buf_pos + 1 + map->debugfs_tot_len >= count) break; /* Format the register */ -- 1.7.10.4