diff options
| author | Xin Long <lucien.xin@gmail.com> | 2020-03-04 16:51:42 +0800 |
|---|---|---|
| committer | Steffen Klassert <steffen.klassert@secunet.com> | 2020-03-04 12:41:29 +0100 |
| commit | d1d17a359ce6901545c075d7401c10179d9cedfd (patch) | |
| tree | d2797217da57d960946e48f731accea6fafeb709 | |
| parent | edf0d283d988c0c7da53fa2cc1388649263470de (diff) | |
esp: remove the skb from the chain when it's enqueued in cryptd_wq
Xiumei found a panic in esp offload:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
RIP: 0010:esp_output_done+0x101/0x160 [esp4]
Call Trace:
? esp_output+0x180/0x180 [esp4]
cryptd_aead_crypt+0x4c/0x90
cryptd_queue_worker+0x6e/0xa0
process_one_work+0x1a7/0x3b0
worker_thread+0x30/0x390
? create_worker+0x1a0/0x1a0
kthread+0x112/0x130
? kthread_flush_work_fn+0x10/0x10
ret_from_fork+0x35/0x40
It was caused by that skb secpath is used in esp_output_done() after it's
been released elsewhere.
The tx path for esp offload is:
__dev_queue_xmit()->
validate_xmit_skb_list()->
validate_xmit_xfrm()->
esp_xmit()->
esp_output_tail()->
aead_request_set_callback(esp_output_done) <--[1]
crypto_aead_encrypt() <--[2]
In [1], .callback is set, and in [2] it will trigger the worker schedule,
later on a kernel thread will call .callback(esp_output_done), as the call
trace shows.
But in validate_xmit_xfrm():
skb_list_walk_safe(skb, skb2, nskb) {
...
err = x->type_offload->xmit(x, skb2, esp_features); [esp_xmit]
...
}
When the err is -EINPROGRESS, which means this skb2 will be enqueued and
later gets encrypted and sent out by .callback later in a kernel thread,
skb2 should be removed fromt skb chain. Otherwise, it will get processed
again outside validate_xmit_xfrm(), which could release skb secpath, and
cause the panic above.
This patch is to remove the skb from the chain when it's enqueued in
cryptd_wq. While at it, remove the unnecessary 'if (!skb)' check.
Fixes: 3dca3f38cfb8 ("xfrm: Separate ESP handling from segmentation for GRO packets.")
Reported-by: Xiumei Mu <xmu@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
| -rw-r--r-- | net/xfrm/xfrm_device.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/net/xfrm/xfrm_device.c b/net/xfrm/xfrm_device.c index 3231ec628544..e2db468cf50e 100644 --- a/net/xfrm/xfrm_device.c +++ b/net/xfrm/xfrm_device.c @@ -78,8 +78,8 @@ struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t featur int err; unsigned long flags; struct xfrm_state *x; - struct sk_buff *skb2, *nskb; struct softnet_data *sd; + struct sk_buff *skb2, *nskb, *pskb = NULL; netdev_features_t esp_features = features; struct xfrm_offload *xo = xfrm_offload(skb); struct sec_path *sp; @@ -168,14 +168,14 @@ struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t featur } else { if (skb == skb2) skb = nskb; - - if (!skb) - return NULL; + else + pskb->next = nskb; continue; } skb_push(skb2, skb2->data - skb_mac_header(skb2)); + pskb = skb2; } return skb; |