From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756190Ab0C3Jnz (ORCPT ); Tue, 30 Mar 2010 05:43:55 -0400 Received: from mail-bw0-f209.google.com ([209.85.218.209]:41909 "EHLO mail-bw0-f209.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756106Ab0C3Jnx (ORCPT ); Tue, 30 Mar 2010 05:43:53 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:mail-followup-to:mime-version :content-type:content-disposition:user-agent; b=i/8Z47Bn/f8Vfkf/QWPeR46HRKgjiJMAx5DEG7QLq8bg/wobAy0SSHrsCmyOGlG6CA 6s287GJ4K877xBgE16oIR78GnXtjmU50vVy/k37mKAeGNNj9d/jxS/pKvfOp+3ZhUhQ/ DGRUaLiM5MK7+bRTcQF1KBrx9XIkutGm5lkpc= Date: Tue, 30 Mar 2010 12:43:42 +0300 From: Dan Carpenter To: Martin Schwidefsky Cc: Heiko Carstens , linux390@de.ibm.com, Hans-Joachim Picht , "Eric W. Biederman" , Sebastian Ott , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [patch] s390: potential buffer overflow Message-ID: <20100330094342.GJ5069@bicker> Mail-Followup-To: Dan Carpenter , Martin Schwidefsky , Heiko Carstens , linux390@de.ibm.com, Hans-Joachim Picht , "Eric W. Biederman" , Sebastian Ott , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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 --- I don't have a cross compile environment to compile this. Sorry. :/ diff --git a/drivers/s390/char/sclp_async.c b/drivers/s390/char/sclp_async.c index f449c69..72c2e90 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) @@ -99,6 +99,7 @@ static int proc_handler_callhome(struct ctl_table *ctl, int write, static struct ctl_table callhome_table[] = { { .procname = "callhome", + .maxlen = 3, .mode = 0644, .proc_handler = proc_handler_callhome, },