From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752780Ab3J3RQf (ORCPT ); Wed, 30 Oct 2013 13:16:35 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:21318 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752040Ab3J3RQd (ORCPT ); Wed, 30 Oct 2013 13:16:33 -0400 Date: Wed, 30 Oct 2013 20:12:51 +0300 From: Dan Carpenter To: "John W. Linville" Cc: libertas-dev@lists.infradead.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [patch v2] libertas: potential oops in debugfs Message-ID: <20131030171251.GA4130@longonot.mountain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131025144452.GA28451@ngolde.de> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If we do a zero size allocation then it will oops. Also we can't be sure the user passes us a NUL terminated string so I've added a terminator. This code can only be triggered by root. Reported-by: Nico Golde Reported-by: Fabian Yamaguchi Signed-off-by: Dan Carpenter diff --git a/drivers/net/wireless/libertas/debugfs.c b/drivers/net/wireless/libertas/debugfs.c index 668dd27..1917348 100644 --- a/drivers/net/wireless/libertas/debugfs.c +++ b/drivers/net/wireless/libertas/debugfs.c @@ -913,7 +913,10 @@ static ssize_t lbs_debugfs_write(struct file *f, const char __user *buf, char *p2; struct debug_data *d = f->private_data; - pdata = kmalloc(cnt, GFP_KERNEL); + if (cnt == 0) + return 0; + + pdata = kmalloc(cnt + 1, GFP_KERNEL); if (pdata == NULL) return 0; @@ -922,6 +925,7 @@ static ssize_t lbs_debugfs_write(struct file *f, const char __user *buf, kfree(pdata); return 0; } + pdata[cnt] = '\0'; p0 = pdata; for (i = 0; i < num_of_items; i++) {