linux/net/xfrm
subashab@codeaurora.org 0c4fb66a93 xfrm: Fix crash observed during device unregistration and decryption
[ Upstream commit 071d36bf21 ]

A crash is observed when a decrypted packet is processed in receive
path. get_rps_cpus() tries to dereference the skb->dev fields but it
appears that the device is freed from the poison pattern.

[<ffffffc000af58ec>] get_rps_cpu+0x94/0x2f0
[<ffffffc000af5f94>] netif_rx_internal+0x140/0x1cc
[<ffffffc000af6094>] netif_rx+0x74/0x94
[<ffffffc000bc0b6c>] xfrm_input+0x754/0x7d0
[<ffffffc000bc0bf8>] xfrm_input_resume+0x10/0x1c
[<ffffffc000ba6eb8>] esp_input_done+0x20/0x30
[<ffffffc0000b64c8>] process_one_work+0x244/0x3fc
[<ffffffc0000b7324>] worker_thread+0x2f8/0x418
[<ffffffc0000bb40c>] kthread+0xe0/0xec

-013|get_rps_cpu(
     |    dev = 0xFFFFFFC08B688000,
     |    skb = 0xFFFFFFC0C76AAC00 -> (
     |      dev = 0xFFFFFFC08B688000 -> (
     |        name =
"......................................................
     |        name_hlist = (next = 0xAAAAAAAAAAAAAAAA, pprev =
0xAAAAAAAAAAA

Following are the sequence of events observed -

- Encrypted packet in receive path from netdevice is queued
- Encrypted packet queued for decryption (asynchronous)
- Netdevice brought down and freed
- Packet is decrypted and returned through callback in esp_input_done
- Packet is queued again for process in network stack using netif_rx

Since the device appears to have been freed, the dereference of
skb->dev in get_rps_cpus() leads to an unhandled page fault
exception.

Fix this by holding on to device reference when queueing packets
asynchronously and releasing the reference on call back return.

v2: Make the change generic to xfrm as mentioned by Steffen and
update the title to xfrm

Suggested-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jerome Stanislaus <jeromes@codeaurora.org>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
History 2016-05-01 00:06:14 +02:00
..
Kconfig net/xfrm: remove depends on CONFIG_EXPERIMENTAL 2013-01-11 11:40:03 -08:00
Makefile xfrm: make xfrm_algo.c a module 2012-05-15 13:13:34 -04:00
xfrm_algo.c net: move pskb_put() to core code 2013-11-07 19:28:58 -05:00
xfrm_hash.c net: allow GFP_HIGHMEM in __vmalloc() 2010-11-21 10:04:04 -08:00
xfrm_hash.h net: misc: Remove extern from function prototypes 2013-10-19 19:12:11 -04:00
xfrm_input.c xfrm: Fix crash observed during device unregistration and decryption 2016-05-01 00:06:14 +02:00
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 net: make skb_gso_segment error handling more robust 2015-05-20 13:25:55 +01:00
xfrm_policy.c xfrm: dst_entries_init() per-net dst_ops 2016-01-28 11:57:51 +00:00
xfrm_proc.c net: clean up snmp stats code 2014-05-07 16:06:05 -04:00
xfrm_replay.c xfrm: Fix aevent generation for each received packet 2013-09-25 07:32:48 +02:00
xfrm_state.c xfrm: fix a race in xfrm_state_lookup_byspi 2015-06-11 11:25:00 +01:00
xfrm_sysctl.c net: Don't export sysctls to unprivileged users 2012-11-18 20:30:55 -05:00
xfrm_user.c xfrm: Fix installation of AH IPsec SAs 2014-06-30 07:42:12 +02:00