path: root/net/xfrm/xfrm_input.c
diff options
authorsubashab@codeaurora.org <subashab@codeaurora.org>2016-03-23 22:39:50 -0600
committerDavid S. Miller <davem@davemloft.net>2016-03-24 14:29:36 -0400
commit071d36bf21bcc837be00cea55bcef8d129e7f609 (patch)
tree6440db1a522f4a2fbe17f6c5ebc1b2611e5f7771 /net/xfrm/xfrm_input.c
parentMerge tag 'trace-v4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace (diff)
xfrm: Fix crash observed during device unregistration and decryption
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>
Diffstat (limited to 'net/xfrm/xfrm_input.c')
1 files changed, 3 insertions, 0 deletions
diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index ad7f5b3f9b61..1c4ad477ce93 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -292,12 +292,15 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
XFRM_SKB_CB(skb)->seq.input.hi = seq_hi;
+ dev_hold(skb->dev);
nexthdr = x->type->input(x, skb);
if (nexthdr == -EINPROGRESS)
return 0;
+ dev_put(skb->dev);
if (nexthdr <= 0) {
if (nexthdr == -EBADMSG) {