From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932105Ab2L1Tnh (ORCPT ); Fri, 28 Dec 2012 14:43:37 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:55265 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754736Ab2L1TST (ORCPT ); Fri, 28 Dec 2012 14:18:19 -0500 Message-Id: <20121228190354.138959026@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Fri, 28 Dec 2012 20:05:24 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Mark Brown Subject: [ 114/173] regmap: debugfs: Avoid overflows for very small reads In-Reply-To: <20121228190330.025298996@decadent.org.uk> X-SA-Exim-Connect-IP: 151.217.219.220 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 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mark Brown commit db04328c167ff8e7c57f4a3532214aeada3a82fd upstream. 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 [bwh: Backported to 3.2: formatted length is tot_len] Signed-off-by: Ben Hutchings --- drivers/base/regmap/regmap-debugfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/base/regmap/regmap-debugfs.c +++ b/drivers/base/regmap/regmap-debugfs.c @@ -67,7 +67,7 @@ static ssize_t regmap_map_read_file(stru /* If we're in the region the user is trying to read */ if (p >= *ppos) { /* ...but not beyond it */ - if (buf_pos >= count - 1 - tot_len) + if (buf_pos + 1 + tot_len >= count) break; /* Format the register */