From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758408Ab3AOWcP (ORCPT ); Tue, 15 Jan 2013 17:32:15 -0500 Received: from mail.kernel.org ([198.145.19.201]:42590 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758376Ab3AOWcI (ORCPT ); Tue, 15 Jan 2013 17:32:08 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Mark Brown Subject: [ 120/221] regmap: debugfs: Avoid overflows for very small reads Date: Tue, 15 Jan 2013 10:50:47 -0800 Message-Id: <20130115185006.701616100@linuxfoundation.org> X-Mailer: git-send-email 1.8.1.336.g94702dd In-Reply-To: <20130115184958.025580322@linuxfoundation.org> References: <20130115184958.025580322@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.7-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 Cc: stable@vger.kernel.org --- 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 @@ -90,7 +90,7 @@ 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 */