Affected: Alpaquita:23: linux-lts, Alpaquita:stream: linux-lts

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

sched/psi: use kernfs polling functions for PSI trigger polling

Destroying psi trigger in cgroup_file_release causes UAF issues when a cgroup is removed from under a polling process. This is happening because cgroup removal causes a call to cgroup_file_release while the actual file is still alive. Destroying the trigger at this point would also destroy its waitqueue head and if there is still a polling process on that file accessing the waitqueue, it will step on the freed pointer:

do_select vfs_poll do_rmdir cgroup_rmdir kernfs_drain_open_files cgroup_file_release cgroup_pressure_release psi_trigger_destroy wake_up_pollfree(&t->event_wait) // vfs_poll is unblocked synchronize_rcu kfree(t) poll_freewait -> UAF access to the trigger's waitqueue head

Patch [1] fixed this issue for epoll() case using wake_up_pollfree(), however the same issue exists for synchronous poll() case. The root cause of this issue is that the lifecycles of the psi trigger's waitqueue and of the file associated with the trigger are different. Fix this by using kernfs_generic_poll function when polling on cgroup-specific psi t…

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

sched/psi: use kernfs polling functions for PSI trigger polling

Destroying psi trigger in cgroup_file_release causes UAF issues when a cgroup is removed from under a polling process. This is happening because cgroup removal causes a call to cgroup_file_release while the actual file is still alive. Destroying the trigger at this point would also destroy its waitqueue head and if there is still a polling process on that file accessing the waitqueue, it will step on the freed pointer:

do_select vfs_poll do_rmdir cgroup_rmdir kernfs_drain_open_files cgroup_file_release cgroup_pressure_release psi_trigger_destroy wake_up_pollfree(&t->event_wait) // vfs_poll is unblocked synchronize_rcu kfree(t) poll_freewait -> UAF access to the trigger's waitqueue head

Patch [1] fixed this issue for epoll() case using wake_up_pollfree(), however the same issue exists for synchronous poll() case. The root cause of this issue is that the lifecycles of the psi trigger's waitqueue and of the file associated with the trigger are different. Fix this by using kernfs_generic_poll function when polling on cgroup-specific psi t…

kernel: use after free in i2c kernel: bluetooth: BR/EDR Bluetooth Impersonation Attacks (BIAS) kernel: hwmon: (lm90) Prevent integer overflow/underflow in hysteresis calculations kernel: asix: fix uninit-value in asix_mdio_read() kernel: tty: tty_buffer: Fix the softlockup issue in flush_to_ldisc kernel: hwmon: (w83793) Fix NULL pointer dereference by removing unnecessary structure field kernel: hwmon: (w83791d) Fix NULL pointer dereference by removing unnecessary structure field kernel: powerpc/64s: fix program check interrupt emergency stack path kernel: powerpc/64s: Fix unrecoverable MCE calling async handler from NMI kernel: lib/generic-radix-tree.c: Don't overflow in peek() kernel: powerpc/smp: do not decrement idle task preempt count in CPU offline kernel: can: isotp: isotp_sendmsg(): add result check for wait_event_interruptible() kernel: usbnet: sanity check for maxpacket kernel: nvmem: Fix shift-out-of-bound (UBSAN) with byte size cells kernel: aio: fix use-after-free due to missing POLLFREE handling kernel: powerpc/pseries: Fix potential memleak in papr_get_attr() kernel: of: fdt: fix off-by-one error in unflatten_dt_nodes() kernel: thermal/int340x_thermal: handle data_vault when the value is ZERO_SIZE_PTR kernel: vt_ioctl: fix array_index_nospec in vt_setactivate kernel: bpf: Fix crash due to out of bounds access into reg2btf_ids. kernel: lz4: fix LZ4_decompress_safe_partial read out of bound kernel: x86/mce: Work around an erratum on fast string copy instructions…

Security update for the Linux Kernel

Affected: Ubuntu:16.04:LTS: linux-hwe-edge, Ubuntu:18.04:LTS: linux-aws-5.0, Ubuntu:18.04:LTS: linux-aws-5.3, Ubuntu:Pro:18.04:LTS: linux-aws-5.4, Ubuntu:18.04:LTS: linux-azure, Ubuntu:18.04:LTS: linux-azure-5.3, Ubuntu:Pro:18.04:LTS: linux-azure-5.4, Ubuntu:18.04:LTS: linux-azure-edge, Ubuntu:18.04:LTS: linux-gcp, Ubuntu:18.04:LTS: linux-gcp-5.3 and 144 more

In the Linux kernel, the following vulnerability has been resolved: sched/psi: use kernfs polling functions for PSI trigger polling Destroying psi trigger in cgroup_file_release causes UAF issues when a cgroup is removed from under a polling process. This is happening because cgroup removal causes a call to cgroup_file_release while the actual file is still alive. Destroying the trigger at this point would also destroy its waitqueue head and if there is still a polling process on that file accessing the waitqueue, it will step on the freed pointer: do_select vfs_poll do_rmdir cgroup_rmdir kernfs_drain_open_files cgroup_file_release cgroup_pressure_release psi_trigger_destroy wake_up_pollfree(&t->event_wait) // vfs_poll is unblocked synchronize_rcu kfree(t) poll_freewait -> UAF access to the trigger's waitqueue head Patch [1] fixed this issue for epoll() case using wake_up_pollfree(), however the same issue exists for synchronous poll() case. The root cause of this issue is that the lifecycles of the psi trigger's waitqueue and of the file associated with the trigger are different. Fix this by using kernfs_generic_poll function when polling on cgroup-specific psi trigg…

Ein Angreifer kann mehrere Schwachstellen im Linux-Kernel ausnutzen, um nicht näher spezifizierte Angriffe durchzuführen, die möglicherweise zu einer Denial-of-Service- Bedingung führen oder eine Speicherbeschädigung verursachen können.