From d1ac8a98f312da20784723b53c62ad67766d5cb7 Mon Sep 17 00:00:00 2001
From: Mateusz Jurczyk <mjurczyk@google.com>
Date: Wed, 24 May 2017 12:42:26 +0200
Subject: nfc: Ensure presence of required attributes in the activate_target
 handler

commit a0323b979f81ad2deb2c8836eab506534891876a upstream.

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 <mjurczyk@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
index ea023b3..102c681 100644
--- a/net/nfc/netlink.c
+++ b/net/nfc/netlink.c
@@ -910,7 +910,9 @@ 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]);
-- 
cgit v0.10.2