Return-path: Received: from mail-wm0-f52.google.com ([74.125.82.52]:37469 "EHLO mail-wm0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763408AbdEXKmb (ORCPT ); Wed, 24 May 2017 06:42:31 -0400 Received: by mail-wm0-f52.google.com with SMTP id d127so63105825wmf.0 for ; Wed, 24 May 2017 03:42:30 -0700 (PDT) From: Mateusz Jurczyk To: Samuel Ortiz , "David S. Miller" Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, security@kernel.org Subject: [PATCH] nfc: Ensure presence of required attributes in the activate_target netlink handler Date: Wed, 24 May 2017 12:42:26 +0200 Message-Id: <20170524104226.14841-1-mjurczyk@google.com> (sfid-20170524_124354_594408_E5ECD255) Sender: linux-wireless-owner@vger.kernel.org List-ID: Check that the NFC_ATTR_TARGET_INDEX and NFC_ATTR_PROTOCOLS attributes (in addition to NFC_ATTR_DEVICE_INDEX) are provided by the netlink client prior to accessing them. This prevents potential unhandled NULL pointer dereference exceptions which can be triggered by malicious user-mode programs, if they omit one or both of these attributes. Signed-off-by: Mateusz Jurczyk --- net/nfc/netlink.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c index 6b0850e63e09..b251fb936a27 100644 --- a/net/nfc/netlink.c +++ b/net/nfc/netlink.c @@ -907,7 +907,9 @@ static int nfc_genl_activate_target(struct sk_buff *skb, struct genl_info *info) u32 device_idx, target_idx, protocol; int rc; - if (!info->attrs[NFC_ATTR_DEVICE_INDEX]) + if (!info->attrs[NFC_ATTR_DEVICE_INDEX] || + !info->attrs[NFC_ATTR_TARGET_INDEX] || + !info->attrs[NFC_ATTR_PROTOCOLS]) return -EINVAL; device_idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]); -- 2.13.0.219.gdb65acc882-goog