Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759538Ab2HIUEs (ORCPT ); Thu, 9 Aug 2012 16:04:48 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:33816 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750848Ab2HIUEq (ORCPT ); Thu, 9 Aug 2012 16:04:46 -0400 Message-ID: <5024179D.30308@inktank.com> Date: Thu, 09 Aug 2012 13:03:41 -0700 From: Alex Elder User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120714 Thunderbird/14.0 MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: [PATCH] lib/parser.c: avoid overflow in match_number() Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2121 Lines: 65 The result of converting an integer value to another signed integer type that's unable to represent the original value is implementation defined. (See notes in section 6.3.1.3 of the C standard.) In match_number(), the result of simple_strtol() (which returns type long) is assigned to a value of type int. Instead, handle the result of simple_strtol() in a well-defined way, and return -ERANGE if the result won't fit in the int variable used to hold the parsed result. No current callers pay attention to the particular error value returned, so this additional return code shouldn't do any harm. Signed-off-by: Alex Elder --- lib/parser.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) Index: b/lib/parser.c =================================================================== --- a/lib/parser.c +++ b/lib/parser.c @@ -122,13 +122,14 @@ int match_token(char *s, const match_tab * * Description: Given a &substring_t and a base, attempts to parse the substring * as a number in that base. On success, sets @result to the integer represented - * by the string and returns 0. Returns either -ENOMEM or -EINVAL on failure. + * by the string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure. */ static int match_number(substring_t *s, int *result, int base) { char *endp; char *buf; int ret; + long val; size_t len = s->to - s->from; buf = kmalloc(len + 1, GFP_KERNEL); @@ -136,10 +137,15 @@ static int match_number(substring_t *s, return -ENOMEM; memcpy(buf, s->from, len); buf[len] = '\0'; - *result = simple_strtol(buf, &endp, base); + ret = 0; + val = simple_strtol(buf, &endp, base); if (endp == buf) ret = -EINVAL; + else if (val < (long) INT_MIN || val > (long) INT_MAX) + ret = -ERANGE; + else + *result = (int) val; kfree(buf); return ret; } -- 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/