Commit 2a0c451a authored by Thomas Graf's avatar Thomas Graf Committed by David S. Miller
Browse files

ipv6: Prevent access to uninitialized fib_table_hash via /proc/net/ipv6_route 



/proc/net/ipv6_route reflects the contents of fib_table_hash. The proc
handler is installed in ip6_route_net_init() whereas fib_table_hash is
allocated in fib6_net_init() _after_ the proc handler has been installed.

This opens up a short time frame to access fib_table_hash with its pants
down.

fib6_init() as a whole can't be moved to an earlier position as it also
registers the rtnetlink message handlers which should be registered at
the end. Therefore split it into fib6_init() which is run early and
fib6_init_late() to register the rtnetlink message handlers.

Signed-off-by: default avatarThomas Graf <tgraf@suug.ch>
Reviewed-by: default avatarNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0f6efff9

include/net/ip6_fib.h

+2 −0
Original line number Diff line number Diff line
@@ -271,6 +271,8 @@ extern void fib6_run_gc(unsigned long expires, 
extern void			fib6_gc_cleanup(void);



extern int			fib6_init(void);

extern int			fib6_init_late(void);

extern void			fib6_cleanup_late(void);



#ifdef CONFIG_IPV6_MULTIPLE_TABLES

extern int			fib6_rules_init(void);

net/ipv6/ip6_fib.c

+11 −7
Original line number Diff line number Diff line
@@ -1692,21 +1692,25 @@ int __init fib6_init(void) 
	ret = register_pernet_subsys(&fib6_net_ops);

	if (ret)

		goto out_kmem_cache_create;



	ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib,

			      NULL);

	if (ret)

		goto out_unregister_subsys;

out:

	return ret;



out_unregister_subsys:

	unregister_pernet_subsys(&fib6_net_ops);

out_kmem_cache_create:

	kmem_cache_destroy(fib6_node_kmem);

	goto out;

}



int __init fib6_init_late(void)

{

	return __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib,

			       NULL);

}



void fib6_cleanup_late(void)

{

	rtnl_unregister(PF_INET6, RTM_GETROUTE);

}



void fib6_gc_cleanup(void)

{

	unregister_pernet_subsys(&fib6_net_ops);

net/ipv6/route.c

+11 −5
Original line number Diff line number Diff line
@@ -3018,10 +3018,14 @@ int __init ip6_route_init(void) 
	if (ret)

		goto out_kmem_cache;



	ret = register_pernet_subsys(&ip6_route_net_ops);

	ret = fib6_init();

	if (ret)

		goto out_dst_entries;



	ret = register_pernet_subsys(&ip6_route_net_ops);

	if (ret)

		goto out_fib6_init;



	ip6_dst_blackhole_ops.kmem_cachep = ip6_dst_ops_template.kmem_cachep;



	/* Registering of the loopback is done before this portion of code,
@@ -3035,13 +3039,13 @@ int __init ip6_route_init(void) 
	init_net.ipv6.ip6_blk_hole_entry->dst.dev = init_net.loopback_dev;

	init_net.ipv6.ip6_blk_hole_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev);

  #endif

	ret = fib6_init();

	ret = fib6_init_late();

	if (ret)

		goto out_register_subsys;



	ret = xfrm6_init();

	if (ret)

		goto out_fib6_init;

		goto out_fib6_init_late;



	ret = fib6_rules_init();

	if (ret)
@@ -3064,10 +3068,12 @@ fib6_rules_init: 
	fib6_rules_cleanup();

xfrm6_init:

	xfrm6_fini();

out_fib6_init:

	fib6_gc_cleanup();

out_fib6_init_late:

	fib6_cleanup_late();

out_register_subsys:

	unregister_pernet_subsys(&ip6_route_net_ops);

out_fib6_init:

	fib6_gc_cleanup();

out_dst_entries:

	dst_entries_destroy(&ip6_dst_blackhole_ops);

out_kmem_cache:

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