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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 <syzkaller@googlegroups.com>,
        Willem de Bruijn <willemb@google.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.14 017/101] packet: validate address length
Date:   Mon,  7 Jan 2019 13:32:05 +0100
Message-Id: <20190107105333.434936297@linuxfoundation.org>
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4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Willem de Bruijn <willemb@google.com>

[ Upstream commit 99137b7888f4058087895d035d81c6b2d31015c5 ]

Packet sockets with SOCK_DGRAM may pass an address for use in
dev_hard_header. Ensure that it is of sufficient length.

Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/packet/af_packet.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2665,6 +2665,8 @@ static int tpacket_snd(struct packet_soc
 		proto	= saddr->sll_protocol;
 		addr	= saddr->sll_addr;
 		dev = dev_get_by_index(sock_net(&po->sk), saddr->sll_ifindex);
+		if (addr && dev && saddr->sll_halen < dev->addr_len)
+			goto out;
 	}
 
 	err = -ENXIO;
@@ -2863,6 +2865,8 @@ static int packet_snd(struct socket *soc
 		proto	= saddr->sll_protocol;
 		addr	= saddr->sll_addr;
 		dev = dev_get_by_index(sock_net(sk), saddr->sll_ifindex);
+		if (addr && dev && saddr->sll_halen < dev->addr_len)
+			goto out;
 	}
 
 	err = -ENXIO;