[PATCH 4.4 044/104] packet: Do not leak dev refcounts on error exit

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

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

From: Jason Gunthorpe <j...@mellanox.com>

[ Upstream commit d972f3dce8d161e2142da0ab1ef25df00e2f21a9 ]

'dev' is non NULL when the addr_len check triggers so it must goto a label
that does the dev_put otherwise dev will have a leaked refcount.

This bug causes the ib_ipoib module to become unloadable when using
systemd-network as it triggers this check on InfiniBand links.

Fixes: 99137b7888f4 ("packet: validate address length")
Reported-by: Leon Romanovsky <leo...@mellanox.com>
Signed-off-by: Jason Gunthorpe <j...@mellanox.com>
Acked-by: Willem de Bruijn <will...@google.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 net/packet/af_packet.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2514,7 +2514,7 @@ static int tpacket_snd(struct packet_soc
                addr    = saddr->sll_halen ? saddr->sll_addr : NULL;
                dev = dev_get_by_index(sock_net(&po->sk), saddr->sll_ifindex);
                if (addr && dev && saddr->sll_halen < dev->addr_len)
-                       goto out;
+                       goto out_put;
        }
 
        err = -ENXIO;
@@ -2683,7 +2683,7 @@ static int packet_snd(struct socket *soc
                addr    = saddr->sll_halen ? saddr->sll_addr : NULL;
                dev = dev_get_by_index(sock_net(sk), saddr->sll_ifindex);
                if (addr && dev && saddr->sll_halen < dev->addr_len)
-                       goto out;
+                       goto out_unlock;
        }
 
        err = -ENXIO;