| Message ID | 1461700422-3506-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c index 85d1d47..f53c2ab 100644 --- a/net/xfrm/xfrm_input.c +++ b/net/xfrm/xfrm_input.c @@ -277,12 +277,15 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type) XFRM_SKB_CB(skb)->seq.input.hi = seq_hi; skb_dst_force(skb); + dev_hold(skb->dev); nexthdr = x->type->input(x, skb); if (nexthdr == -EINPROGRESS) return 0; resume: + dev_put(skb->dev); + spin_lock(&x->lock); if (nexthdr <= 0) { if (nexthdr == -EBADMSG) {
This is a note to let you know that I have just added a patch titled xfrm: Fix crash observed during device unregistration and decryption to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue This patch is scheduled to be released in version 3.19.8-ckt20. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.19.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From c15d4f3b0c8f5f8e9804b81ad662ff10caefda7e Mon Sep 17 00:00:00 2001 From: "subashab@codeaurora.org" <subashab@codeaurora.org> Date: Wed, 23 Mar 2016 22:39:50 -0600 Subject: xfrm: Fix crash observed during device unregistration and decryption [ Upstream commit 071d36bf21bcc837be00cea55bcef8d129e7f609 ] 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: Kamal Mostafa <kamal@canonical.com> --- net/xfrm/xfrm_input.c | 3 +++ 1 file changed, 3 insertions(+) -- 2.7.4