diff options
| author | Shihuang Liu <shlomojune6@gmail.com> | 2026-07-22 19:39:19 +0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-07-23 07:00:35 -0700 |
| commit | ea20c44935d6142daecfa9b39d635033a7553e1b (patch) | |
| tree | 8723a33edd251ec6e448ffe6ae72c95ca66547ae | |
| parent | 249447ff83967980ed6751660665cc682ff84e0c (diff) | |
amt: fix use-after-free in AMT delayed works
When an AMT device is removed, pending delayed works can still access
the freed amt_dev structure, which may result in kernel crashes or
memory corruption.
amt_dev_stop() cancels req_wq and discovery_wq with
cancel_delayed_work_sync(), but these works can be scheduled again
from event_wq after the cancellation. This allows delayed works to
access the freed amt_dev structure after the netdev has been released.
The following is a simple race scenario:
CPU0 CPU1
amt_dev_stop()
cancel_delayed_work_sync()
amt_event_work()
mod_delayed_work(req_wq)
free netdev
req_wq accesses freed amt_dev
Use disable_delayed_work_sync() in amt_dev_stop() to prevent req_wq and
discovery_wq from being queued again and wait for running work items
to complete.
The delayed works are disabled after initialization in
amt_newlink() and enabled only when the device is successfully opened.
This keeps the delayed work lifecycle synchronized with the lifetime
of the AMT device.
Fixes: cbc21dc1cfe9 ("amt: add data plane of amt interface")
Cc: stable@vger.kernel.org
Signed-off-by: Shihuang Liu <shlomojune6@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Taehee Yoo <ap420073@gmail.com>
Link: https://patch.msgid.link/20260722113919.7723-1-shlomojune6@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | drivers/net/amt.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/net/amt.c b/drivers/net/amt.c index b733309b866f..182a41d59a75 100644 --- a/drivers/net/amt.c +++ b/drivers/net/amt.c @@ -3034,9 +3034,15 @@ static int amt_dev_open(struct net_device *dev) amt->event_idx = 0; amt->nr_events = 0; + enable_delayed_work(&amt->discovery_wq); + enable_delayed_work(&amt->req_wq); + err = amt_socket_create(amt); - if (err) + if (err) { + disable_delayed_work(&amt->req_wq); + disable_delayed_work(&amt->discovery_wq); return err; + } amt->req_cnt = 0; amt->remote_ip = 0; @@ -3062,8 +3068,8 @@ static int amt_dev_stop(struct net_device *dev) struct sock *sk; int i; - cancel_delayed_work_sync(&amt->req_wq); - cancel_delayed_work_sync(&amt->discovery_wq); + disable_delayed_work_sync(&amt->req_wq); + disable_delayed_work_sync(&amt->discovery_wq); cancel_delayed_work_sync(&amt->secret_wq); /* shutdown */ @@ -3317,6 +3323,8 @@ static int amt_newlink(struct net_device *dev, INIT_DELAYED_WORK(&amt->req_wq, amt_req_work); INIT_DELAYED_WORK(&amt->secret_wq, amt_secret_work); INIT_WORK(&amt->event_wq, amt_event_work); + disable_delayed_work(&amt->req_wq); + disable_delayed_work(&amt->discovery_wq); INIT_LIST_HEAD(&amt->tunnel_list); return 0; err: |