From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Rasmus Villemoes , Mark Brown Subject: [PATCH 4.2 189/258] regmap: debugfs: Ensure we dont underflow when printing access masks Date: Sat, 17 Oct 2015 18:58:22 -0700 Message-Id: <20151018014738.988786807@linuxfoundation.org> In-Reply-To: <20151018014729.976101177@linuxfoundation.org> References: <20151018014729.976101177@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mark Brown commit b763ec17ac762470eec5be8ebcc43e4f8b2c2b82 upstream. If a read is attempted which is smaller than the line length then we may underflow the subtraction we're doing with the unsigned size_t type so move some of the calculation to be additions on the right hand side instead in order to avoid this. Reported-by: Rasmus Villemoes Signed-off-by: Mark Brown Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- 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 @@ -432,7 +432,7 @@ static ssize_t regmap_access_read_file(s /* 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 + tot_len + 1 >= count) break; /* Format the register */