From mboxrd@z Thu Jan 1 00:00:00 1970 From: 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> References: Cc: richard -rw- weinberger , netdev@vger.kernel.org, Mathias Krause To: "David S. Miller" Return-path: 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) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: 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?". -- 1.7.10.4