From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753436AbcAEUZb (ORCPT ); Tue, 5 Jan 2016 15:25:31 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:45115 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752920AbcAETrk (ORCPT ); Tue, 5 Jan 2016 14:47:40 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Andy Shevchenko , Al Viro , Catalin Marinas , Andrew Morton , Linus Torvalds , Kamal Mostafa Subject: [PATCH 4.2.y-ckt 099/211] lib/hexdump.c: truncate output in case of overflow Date: Tue, 5 Jan 2016 11:43:27 -0800 Message-Id: <1452023119-25647-100-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1452023119-25647-1-git-send-email-kamal@canonical.com> References: <1452023119-25647-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.2.8-ckt1 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Shevchenko commit 9f029f540c2f7e010e4922d44ba0dfd05da79f88 upstream. There is a classical off-by-one error in case when we try to place, for example, 1+1 bytes as hex in the buffer of size 6. The expected result is to get an output truncated, but in the reality we get 6 bytes filed followed by terminating NUL. Change the logic how we fill the output in case of byte dumping into limited space. This will follow the snprintf() behaviour by truncating output even on half bytes. Fixes: 114fc1afb2de (hexdump: make it return number of bytes placed in buffer) Signed-off-by: Andy Shevchenko Reported-by: Aaro Koskinen Tested-by: Aaro Koskinen Cc: Al Viro Cc: Catalin Marinas Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Kamal Mostafa --- lib/hexdump.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/lib/hexdump.c b/lib/hexdump.c index 8d74c20..992457b 100644 --- a/lib/hexdump.c +++ b/lib/hexdump.c @@ -169,11 +169,15 @@ int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize, } } else { for (j = 0; j < len; j++) { - if (linebuflen < lx + 3) + if (linebuflen < lx + 2) goto overflow2; ch = ptr[j]; linebuf[lx++] = hex_asc_hi(ch); + if (linebuflen < lx + 2) + goto overflow2; linebuf[lx++] = hex_asc_lo(ch); + if (linebuflen < lx + 2) + goto overflow2; linebuf[lx++] = ' '; } if (j) -- 1.9.1