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, Andy Shevchenko , Aaro Koskinen , Al Viro , Catalin Marinas , Andrew Morton , Linus Torvalds Subject: [PATCH 4.3 024/200] lib/hexdump.c: truncate output in case of overflow Date: Sun, 14 Feb 2016 14:20:31 -0800 Message-Id: <20160214222218.002015676@linuxfoundation.org> In-Reply-To: <20160214222217.084543173@linuxfoundation.org> References: <20160214222217.084543173@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.3-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: Greg Kroah-Hartman --- lib/hexdump.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/lib/hexdump.c +++ b/lib/hexdump.c @@ -169,11 +169,15 @@ int hex_dump_to_buffer(const void *buf, } } 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)