Subject: [PATCH 03/11] packet: Do not leak dev refcounts on error exit

From: Jason Gunthorpe <[email-masked]>
Date: Tue, 8 Jan 2019 23:27:06 +0000

[ 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 <[email-masked]>
Signed-off-by: Jason Gunthorpe <[email-masked]>
Acked-by: Willem de Bruijn <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/packet/af_packet.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 0541cfc93440..b6ea0fadb34f 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2628,7 +2628,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
 		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;
@@ -2828,7 +2828,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
 		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;
-- 
2.20.1