Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
nfc: nci: fix double completion race in nci_data_exchange_complete
nci_close_device() and nci_rx_work can both call nci_data_exchange_complete() concurrently. After commit 4527025d440ce8 (“nfc: nci: fix circular locking dependency in nci_close_device”) moved flush_workqueue(ndev->rx_wq) after mutex_unlock(&ndev->req_lock), rx_work is no longer serialized with the explicit completion call in the close path. Both callers read the non-NULL callback pointer and invoke rawsock_data_exchange_complete(), which calls sock_put() – but only one sock_hold() was taken, so the second sock_put() underflows the refcount and frees the socket while it is still in use.
Replace the bare clear_bit(NCI_DATA_EXCHANGE) with test_and_clear_bit() so that only the first caller proceeds to invoke the callback.
Details
- Affected product:
- Debian 11 ELS
- Affected packages:
- linux @ 5.10.270
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Debian 12 | Planned | — |
| Debian 13 | Planned | — |