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net: fix proc_fs init handling in af_packet and tls 

proc_fs was used, in af_packet, without a surrounding #ifdef,
although there is no hard dependency on proc_fs.
That caused the initialization of the af_packet module to fail
when CONFIG_PROC_FS=n.

Specifically, proc_create_net() was used in af_packet.c,
and when it fails, packet_net_init() returns -ENOMEM.
It will always fail when the kernel is compiled without proc_fs,
because, proc_create_net() for example always returns NULL.

The calling order that starts in af_packet.c is as follows:
packet_init()
register_pernet_subsys()
register_pernet_operations()
__register_pernet_operations()
ops_init()
ops->init() (packet_net_ops.init=packet_net_init())
proc_create_net()

It worked in the past because register_pernet_subsys()'s return value
wasn't checked before this Commit 36096f2f4f ("packet: Fix error path in
packet_init.").
It always returned an error, but was not checked before, so everything
was working even when CONFIG_PROC_FS=n.

The fix here is simply to add the necessary #ifdef.

This also fixes a similar error in tls_proc.c, that was found by Jakub
Kicinski.

Fixes: d26b698dd3 ("net/tls: add skeleton of MIB statistics")
Fixes: 36096f2f4f ("packet: Fix error path in packet_init")
Signed-off-by: Yonatan Linik <yonatanlinik@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Yonatan Linik 2020-12-14 22:25:50 +02:00 committed by Jakub Kicinski
parent 102f19d611
commit a268e0f245
2 changed files with 5 additions and 0 deletions
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2
net/packet/af_packet.c
View File

@ -4629,9 +4629,11 @@ static int __net_init packet_net_init(struct net *net)
mutex_init(&net->packet.sklist_lock);
INIT_HLIST_HEAD(&net->packet.sklist);
#ifdef CONFIG_PROC_FS
if (!proc_create_net("packet", 0, net->proc_net, &packet_seq_ops,
sizeof(struct seq_net_private)))
return -ENOMEM;
#endif /* CONFIG_PROC_FS */
return 0;
}

3
net/tls/tls_proc.c
View File

@ -37,9 +37,12 @@ static int tls_statistics_seq_show(struct seq_file *seq, void *v)
int __net_init tls_proc_init(struct net *net)
{
#ifdef CONFIG_PROC_FS
if (!proc_create_net_single("tls_stat", 0444, net->proc_net,
tls_statistics_seq_show, NULL))
return -ENOMEM;
#endif /* CONFIG_PROC_FS */
return 0;
}