From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754405Ab0C3Qp4 (ORCPT ); Tue, 30 Mar 2010 12:45:56 -0400 Received: from mail-bw0-f209.google.com ([209.85.218.209]:41015 "EHLO mail-bw0-f209.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752536Ab0C3Qpy (ORCPT ); Tue, 30 Mar 2010 12:45:54 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:mail-followup-to:references :mime-version:content-type:content-disposition:in-reply-to :user-agent; b=KOJvRW+H0GAJVakG4o8iQQK0vIQlssuj1dlKN2sx90B0o29RWDGK8xX2tf7IZwjDdR OcAUScDqzui4phXfWJZNHNETCzCpcqkcEHWXy+YG8mv2h1NTbgzPaKKVN0P3APqMbeB6 nYQ6nsoDeVjvvNsRlwZqbMwWJUuUqXeWx6xBU= Date: Tue, 30 Mar 2010 19:45:42 +0300 From: Dan Carpenter To: "Eric W. Biederman" Cc: Martin Schwidefsky , Heiko Carstens , linux390@de.ibm.com, Hans-Joachim Picht , Sebastian Ott , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [patch v2] s390: potential buffer overflow Message-ID: <20100330164542.GN5069@bicker> Mail-Followup-To: Dan Carpenter , "Eric W. Biederman" , Martin Schwidefsky , Heiko Carstens , linux390@de.ibm.com, Hans-Joachim Picht , Sebastian Ott , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org References: <20100330094342.GJ5069@bicker> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org "len" hasn't been properly range checked so we shouldn't use it as an array offset. This can only be written to by root but it would still be annoying to accidentally write more than 3 characters and corrupt your memory. Signed-off-by: Dan Carpenter --- v2. Removed a superfluous chunk from my first patch. I didn't understand how ->maxlen worked. diff --git a/drivers/s390/char/sclp_async.c b/drivers/s390/char/sclp_async.c index f449c69..38a9f55 100644 --- a/drivers/s390/char/sclp_async.c +++ b/drivers/s390/char/sclp_async.c @@ -84,7 +84,7 @@ static int proc_handler_callhome(struct ctl_table *ctl, int write, rc = copy_from_user(buf, buffer, sizeof(buf)); if (rc != 0) return -EFAULT; - buf[len - 1] = '\0'; + buf[sizeof(buf) - 1] = '\0'; if (strict_strtoul(buf, 0, &val) != 0) return -EINVAL; if (val != 0 && val != 1)