From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758187AbaHHVa4 (ORCPT ); Fri, 8 Aug 2014 17:30:56 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:40697 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757169AbaHHUs7 (ORCPT ); Fri, 8 Aug 2014 16:48:59 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: "Don A. Bailey" , Greg Kroah-Hartman , Kamal Mostafa Subject: [PATCH 3.13 055/259] lz4: add overrun checks to lz4_uncompress_unknownoutputsize() Date: Fri, 8 Aug 2014 13:37:58 -0700 Message-Id: <1407530482-4483-56-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1407530482-4483-1-git-send-email-kamal@canonical.com> References: <1407530482-4483-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11.6 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Greg Kroah-Hartman commit 4a3a99045177369700c60d074c0e525e8093b0fc upstream. Jan points out that I forgot to make the needed fixes to the lz4_uncompress_unknownoutputsize() function to mirror the changes done in lz4_decompress() with regards to potential pointer overflows. The only in-kernel user of this function is the zram code, which only takes data from a valid compressed buffer that it made itself, so it's not a big issue. But due to external kernel modules using this function, it's better to be safe here. Reported-by: Jan Beulich Cc: "Don A. Bailey" Signed-off-by: Greg Kroah-Hartman Signed-off-by: Kamal Mostafa --- lib/lz4/lz4_decompress.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c index b74da44..7a85967 100644 --- a/lib/lz4/lz4_decompress.c +++ b/lib/lz4/lz4_decompress.c @@ -192,6 +192,8 @@ static int lz4_uncompress_unknownoutputsize(const char *source, char *dest, int s = 255; while ((ip < iend) && (s == 255)) { s = *ip++; + if (unlikely(length > (size_t)(length + s))) + goto _output_error; length += s; } } @@ -232,6 +234,8 @@ static int lz4_uncompress_unknownoutputsize(const char *source, char *dest, if (length == ML_MASK) { while (ip < iend) { int s = *ip++; + if (unlikely(length > (size_t)(length + s))) + goto _output_error; length += s; if (s == 255) continue; @@ -284,7 +288,7 @@ static int lz4_uncompress_unknownoutputsize(const char *source, char *dest, /* write overflow error detected */ _output_error: - return (int) (-(((char *) ip) - source)); + return -1; } int lz4_decompress(const unsigned char *src, size_t *src_len, -- 1.9.1