Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965471AbaGRNJS (ORCPT ); Fri, 18 Jul 2014 09:09:18 -0400 Received: from bband-dyn38.178-41-141.t-com.sk ([178.41.141.38]:17428 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S965267AbaGRNJK (ORCPT ); Fri, 18 Jul 2014 09:09:10 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Greg Kroah-Hartman , "Don A. Bailey" , Jiri Slaby Subject: [PATCH 3.12 054/170] lz4: add overrun checks to lz4_uncompress_unknownoutputsize() Date: Fri, 18 Jul 2014 14:10:59 +0200 Message-Id: X-Mailer: git-send-email 2.0.0 In-Reply-To: <48e8cad86bb1241c08bdaa80db022c25068ff8e0.1405685481.git.jslaby@suse.cz> References: <48e8cad86bb1241c08bdaa80db022c25068ff8e0.1405685481.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg Kroah-Hartman 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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: Jiri Slaby --- 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 b74da447e81e..7a85967060a5 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, -- 2.0.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/