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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+d4c07de0144f6f63be3a@syzkaller.appspotmail.com,
        Alexander Aring <aahringo@redhat.com>,
        Stefan Schmidt <stefan@datenfreihafen.org>
Subject: [PATCH 4.19 58/66] net: ieee802154: nl-mac: fix check on panid
Date:   Mon, 12 Apr 2021 10:41:04 +0200
Message-Id: <20210412083959.999943252@linuxfoundation.org>
In-Reply-To: <20210412083958.129944265@linuxfoundation.org>
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From: Alexander Aring <aahringo@redhat.com>

commit 6f7f657f24405f426212c09260bf7fe8a52cef33 upstream.

This patch fixes a null pointer derefence for panid handle by move the
check for the netlink variable directly before accessing them.

Reported-by: syzbot+d4c07de0144f6f63be3a@syzkaller.appspotmail.com
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20210228151817.95700-4-aahringo@redhat.com
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ieee802154/nl-mac.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/net/ieee802154/nl-mac.c
+++ b/net/ieee802154/nl-mac.c
@@ -559,9 +559,7 @@ ieee802154_llsec_parse_key_id(struct gen
 	desc->mode = nla_get_u8(info->attrs[IEEE802154_ATTR_LLSEC_KEY_MODE]);
 
 	if (desc->mode == IEEE802154_SCF_KEY_IMPLICIT) {
-		if (!info->attrs[IEEE802154_ATTR_PAN_ID] &&
-		    !(info->attrs[IEEE802154_ATTR_SHORT_ADDR] ||
-		      info->attrs[IEEE802154_ATTR_HW_ADDR]))
+		if (!info->attrs[IEEE802154_ATTR_PAN_ID])
 			return -EINVAL;
 
 		desc->device_addr.pan_id = nla_get_shortaddr(info->attrs[IEEE802154_ATTR_PAN_ID]);
@@ -570,6 +568,9 @@ ieee802154_llsec_parse_key_id(struct gen
 			desc->device_addr.mode = IEEE802154_ADDR_SHORT;
 			desc->device_addr.short_addr = nla_get_shortaddr(info->attrs[IEEE802154_ATTR_SHORT_ADDR]);
 		} else {
+			if (!info->attrs[IEEE802154_ATTR_HW_ADDR])
+				return -EINVAL;
+
 			desc->device_addr.mode = IEEE802154_ADDR_LONG;
 			desc->device_addr.extended_addr = nla_get_hwaddr(info->attrs[IEEE802154_ATTR_HW_ADDR]);
 		}