linux/net/xfrm
Florian Westphal 862591bf4f xfrm: skip policies marked as dead while rehashing
syzkaller triggered following KASAN splat:

BUG: KASAN: slab-out-of-bounds in xfrm_hash_rebuild+0xdbe/0xf00 net/xfrm/xfrm_policy.c:618
read of size 2 at addr ffff8801c8e92fe4 by task kworker/1:1/23 [..]
Workqueue: events xfrm_hash_rebuild [..]
 __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:428
 xfrm_hash_rebuild+0xdbe/0xf00 net/xfrm/xfrm_policy.c:618
 process_one_work+0xbbf/0x1b10 kernel/workqueue.c:2112
 worker_thread+0x223/0x1990 kernel/workqueue.c:2246 [..]

The reproducer triggers:
1016                 if (error) {
1017                         list_move_tail(&walk->walk.all, &x->all);
1018                         goto out;
1019                 }

in xfrm_policy_walk() via pfkey (it sets tiny rcv space, dump
callback returns -ENOBUFS).

In this case, *walk is located the pfkey socket struct, so this socket
becomes visible in the global policy list.

It looks like this is intentional -- phony walker has walk.dead set to 1
and all other places skip such "policies".

Ccing original authors of the two commits that seem to expose this
issue (first patch missed ->dead check, second patch adds pfkey
sockets to policies dumper list).

Fixes: 880a6fab8f ("xfrm: configure policy hash table thresholds by netlink")
Fixes: 12a169e7d8 ("ipsec: Put dumpers on the dump list")
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Timo Teras <timo.teras@iki.fi>
Cc: Christophe Gouault <christophe.gouault@6wind.com>
Reported-by: syzbot <bot+c028095236fcb6f4348811565b75084c754dc729@syzkaller.appspotmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2017-12-30 09:18:47 +01:00
..
Kconfig Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2017-02-16 21:25:49 -05:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xfrm_algo.c xfrm: use IS_ENABLED() instead of checking for built-in or module 2016-09-10 21:19:11 -07:00
xfrm_device.c xfrm: Fix negative device refcount on offload failure. 2017-09-11 10:36:51 +02:00
xfrm_hash.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xfrm_hash.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xfrm_input.c xfrm: Reinject transport-mode packets through tasklet 2017-12-19 08:23:21 +01:00
xfrm_ipcomp.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-11-04 13:48:30 -05:00
xfrm_output.c xfrm: Fix GSO for IPsec with GRE tunnel. 2017-10-31 09:20:35 +01:00
xfrm_policy.c xfrm: skip policies marked as dead while rehashing 2017-12-30 09:18:47 +01:00
xfrm_proc.c proc: Reduce cache miss in xfrm_statistics_seq_show 2016-09-30 01:50:45 -04:00
xfrm_replay.c xfrm: Add xfrm_replay_overflow functions for offloading 2017-04-14 10:07:01 +02:00
xfrm_state.c xfrm: Forbid state updates from changing encap type 2017-12-30 09:18:47 +01:00
xfrm_sysctl.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xfrm_user.c xfrm: Fix stack-out-of-bounds with misconfigured transport mode policies. 2017-12-08 08:07:25 +01:00