In the Linux kernel, the following vulnerability has been resolved:

drivers: usb: host: Fix deadlock in oxu_bus_suspend()

There is a deadlock in oxu_bus_suspend(), which is shown below:

(Thread 1) | (Thread 2) | timer_action() oxu_bus_suspend() | mod_timer() spin_lock_irq() //(1) | (wait a time) ... | oxu_watchdog() del_timer_sync() | spin_lock_irq() //(2) (wait timer to stop) | ...

We hold oxu->lock in position (1) of thread 1, and use del_timer_sync() to wait timer to stop, but timer handler also need oxu->lock in position (2) of thread 2. As a result, oxu_bus_suspend() will block forever.

This patch extracts del_timer_sync() from the protection of spin_lock_irq(), which could let timer handler to obtain the needed lock.

In the Linux kernel, the following vulnerability has been resolved:

drivers: usb: host: Fix deadlock in oxu_bus_suspend()

There is a deadlock in oxu_bus_suspend(), which is shown below:

(Thread 1) | (Thread 2) | timer_action() oxu_bus_suspend() | mod_timer() spin_lock_irq() //(1) | (wait a time) ... | oxu_watchdog() del_timer_sync() | spin_lock_irq() //(2) (wait timer to stop) | ...

We hold oxu->lock in position (1) of thread 1, and use del_timer_sync() to wait timer to stop, but timer handler also need oxu->lock in position (2) of thread 2. As a result, oxu_bus_suspend() will block forever.

This patch extracts del_timer_sync() from the protection of spin_lock_irq(), which could let timer handler to obtain the needed lock.

Affected: openEuler:20.03-LTS-SP4: kernel

The Linux Kernel, the operating system core itself. Security Fix(es):

In the Linux kernel, the following vulnerability has been resolved:

nfc: nci: add flush_workqueue to prevent uaf

Our detector found a concurrent use-after-free bug when detaching an NCI device. The main reason for this bug is the unexpected scheduling between the used delayed mechanism (timer and workqueue).

The race can be demonstrated below:

Thread-1 Thread-2 | nci_dev_up() | nci_open_device() | __nci_request(nci_reset_req) | nci_send_cmd | queue_work(cmd_work) nci_unregister_device() | nci_close_device() | ... del_timer_sync(cmd_timer)[1] | ... | Worker nci_free_device() | nci_cmd_work() kfree(ndev)[3] | mod_timer(cmd_timer)[2]

In short, the cleanup routine thought that the cmd_timer has already been detached by [1] but the mod_timer can re-attach the timer [2], even it is already released [3], resulting in UAF.

This UAF is easy to trigger, crash trace by POC is like below

[ 66.703713] ================================================================== [ 66.703974] BUG: KASAN: use-after-free in enqueue_timer+0x448/0x490 [ 66.703974] Write of size 8 at addr ffff888009fb7058 by task kworker/u4…

Security update for the Linux Kernel

Affected: Ubuntu:Pro:14.04:LTS: linux-azure, Ubuntu:Pro:14.04:LTS: linux, Ubuntu:Pro:14.04:LTS: linux-aws, Ubuntu:Pro:14.04:LTS: linux-lts-xenial, Ubuntu:Pro:16.04:LTS: linux-aws-hwe, Ubuntu:Pro:16.04:LTS: linux-azure, Ubuntu:Pro:16.04:LTS: linux-gcp, Ubuntu:Pro:16.04:LTS: linux-hwe, Ubuntu:Pro:16.04:LTS: linux-oracle, Ubuntu:Pro:16.04:LTS: linux and 145 more

In the Linux kernel, the following vulnerability has been resolved: drivers: usb: host: Fix deadlock in oxu_bus_suspend() There is a deadlock in oxu_bus_suspend(), which is shown below: (Thread 1) | (Thread 2) | timer_action() oxu_bus_suspend() | mod_timer() spin_lock_irq() //(1) | (wait a time) ... | oxu_watchdog() del_timer_sync() | spin_lock_irq() //(2) (wait timer to stop) | ... We hold oxu->lock in position (1) of thread 1, and use del_timer_sync() to wait timer to stop, but timer handler also need oxu->lock in position (2) of thread 2. As a result, oxu_bus_suspend() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_irq(), which could let timer handler to obtain the needed lock.