From patchwork Mon Jul 30 05:45:14 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mathias Krause X-Patchwork-Id: 173962 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 2AB662C0092 for ; Mon, 30 Jul 2012 15:46:22 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751661Ab2G3FqD (ORCPT ); Mon, 30 Jul 2012 01:46:03 -0400 Received: from mail-bk0-f46.google.com ([209.85.214.46]:44899 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751166Ab2G3FqC (ORCPT ); Mon, 30 Jul 2012 01:46:02 -0400 Received: by bkwj10 with SMTP id j10so2653596bkw.19 for ; Sun, 29 Jul 2012 22:46:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; bh=0uGM3vj1Hhow4/rWJFZhWUqPf9WsK0vyZcoU4B5w7Do=; b=z1bySg8Aa1dN2xACT4m9Cu3jTf/NGw7Nuxh2Y7mR9Swe6j2KdkDJsNYuyLqueOCzRo X7jX8N/13+xs3gO4ikDTdF4ou2Mv3lV6JyyJ6KmCU8StIxW7fSTBMhC87nsGE8U7x1dY /jp84ryaDS3a3nwnbNGzmG/kwJcv5YwZIx4LV8SQq/w8OFqjstkC5BSmLktaCu3apVoT b1A6NCNeVUrJEl1jZUCvwpKTx7rIJZAYd0+v9OyJ46jPVv1blKZgn9EzHqjvGYNfRpie tCQPfS8bm7Ntok77V+Aer0BlvjuokgNZB7XDYy95k4M86k0uS0rfGqpVMLz9gMY5frdh mlXQ== Received: by 10.204.145.82 with SMTP id c18mr3464928bkv.133.1343627160664; Sun, 29 Jul 2012 22:46:00 -0700 (PDT) Received: from jig.fritz.box (pD9EB5AF0.dip.t-dialin.net. [217.235.90.240]) by mx.google.com with ESMTPS id u8sm3021799bks.0.2012.07.29.22.45.58 (version=TLSv1/SSLv3 cipher=OTHER); Sun, 29 Jul 2012 22:45:59 -0700 (PDT) From: Mathias Krause To: "David S. Miller" Cc: richard -rw- weinberger , netdev@vger.kernel.org, Mathias Krause Subject: [PATCH v2] net/tun: fix ioctl() based info leaks Date: Mon, 30 Jul 2012 07:45:14 +0200 Message-Id: <1343627114-17899-1-git-send-email-minipli@googlemail.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: References: Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The tun module leaks up to 36 bytes of memory by not fully initializing a structure located on the stack that gets copied to user memory by the TUNGETIFF and SIOCGIFHWADDR ioctl()s. Signed-off-by: Mathias Krause --- v2: - removed braces around else branch - minor adjustment of the commit message drivers/net/tun.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 987aeef..01255ff 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1252,9 +1252,11 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, int vnet_hdr_sz; int ret; - if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) + if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) { if (copy_from_user(&ifr, argp, ifreq_len)) return -EFAULT; + } else + memset(&ifr, 0, sizeof(ifr)); if (cmd == TUNGETFEATURES) { /* Currently this just means: "what IFF flags are valid?".