Commit b520e574 authored by Masahiro Fujiwara's avatar Masahiro Fujiwara Committed by Greg Kroah-Hartman
Browse files

gtp: fix an use-before-init in gtp_newlink()

[ Upstream commit 51467431200b91682b89d31317e35dcbca1469ce ]

*_pdp_find() from gtp_encap_recv() would trigger a crash when a peer
sends GTP packets while creating new GTP device.

RIP: 0010:gtp1_pdp_find.isra.0+0x68/0x90 [gtp]
<SNIP>
Call Trace:
 <IRQ>
 gtp_encap_recv+0xc2/0x2e0 [gtp]
 ? gtp1_pdp_find.isra.0+0x90/0x90 [gtp]
 udp_queue_rcv_one_skb+0x1fe/0x530
 udp_queue_rcv_skb+0x40/0x1b0
 udp_unicast_rcv_skb.isra.0+0x78/0x90
 __udp4_lib_rcv+0x5af/0xc70
 udp_rcv+0x1a/0x20
 ip_protocol_deliver_rcu+0xc5/0x1b0
 ip_local_deliver_finish+0x48/0x50
 ip_local_deliver+0xe5/0xf0
 ? ip_protocol_deliver_rcu+0x1b0/0x1b0

gtp_encap_enable() should be called after gtp_hastable_new() otherwise
*_pdp_find() will access the uninitialized hash table.

Fixes: 1e3a3abd

 ("gtp: make GTP sockets in gtp_newlink optional")
Signed-off-by: default avatarMasahiro Fujiwara <fujiwara.masahiro@gmail.com>
Link: https://lore.kernel.org/r/20201027114846.3924-1-fujiwara.masahiro@gmail.com

Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9921e777
......@@ -663,10 +663,6 @@ static int gtp_newlink(struct net *src_net, struct net_device *dev,
gtp = netdev_priv(dev);
err = gtp_encap_enable(gtp, data);
if (err < 0)
return err;
if (!data[IFLA_GTP_PDP_HASHSIZE]) {
hashsize = 1024;
} else {
......@@ -677,12 +673,16 @@ static int gtp_newlink(struct net *src_net, struct net_device *dev,
err = gtp_hashtable_new(gtp, hashsize);
if (err < 0)
goto out_encap;
return err;
err = gtp_encap_enable(gtp, data);
if (err < 0)
goto out_hashtable;
err = register_netdevice(dev);
if (err < 0) {
netdev_dbg(dev, "failed to register new netdev %d\n", err);
goto out_hashtable;
goto out_encap;
}
gn = net_generic(dev_net(dev), gtp_net_id);
......@@ -693,11 +693,11 @@ static int gtp_newlink(struct net *src_net, struct net_device *dev,
return 0;
out_encap:
gtp_encap_disable(gtp);
out_hashtable:
kfree(gtp->addr_hash);
kfree(gtp->tid_hash);
out_encap:
gtp_encap_disable(gtp);
return err;
}
......
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