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

x86/hyperv: Disable IBT when hypercall page lacks ENDBR instruction

On hardware that supports Indirect Branch Tracking (IBT), Hyper-V VMs with ConfigVersion 9.3 or later support IBT in the guest. However, current versions of Hyper-V have a bug in that there's not an ENDBR64 instruction at the beginning of the hypercall page. Since hypercalls are made with an indirect call to the hypercall page, all hypercall attempts fail with an exception and Linux panics.

A Hyper-V fix is in progress to add ENDBR64. But guard against the Linux panic by clearing X86_FEATURE_IBT if the hypercall page doesn't start with ENDBR. The VM will boot and run without IBT.

If future Linux 32-bit kernels were to support IBT, additional hypercall page hackery would be needed to make IBT work for such kernels in a Hyper-V VM.

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

x86/hyperv: Disable IBT when hypercall page lacks ENDBR instruction

On hardware that supports Indirect Branch Tracking (IBT), Hyper-V VMs with ConfigVersion 9.3 or later support IBT in the guest. However, current versions of Hyper-V have a bug in that there's not an ENDBR64 instruction at the beginning of the hypercall page. Since hypercalls are made with an indirect call to the hypercall page, all hypercall attempts fail with an exception and Linux panics.

A Hyper-V fix is in progress to add ENDBR64. But guard against the Linux panic by clearing X86_FEATURE_IBT if the hypercall page doesn't start with ENDBR. The VM will boot and run without IBT.

If future Linux 32-bit kernels were to support IBT, additional hypercall page hackery would be needed to make IBT work for such kernels in a Hyper-V VM.

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:Pro:14.04:LTS: linux, Ubuntu:Pro:14.04:LTS: linux-aws, Ubuntu:Pro:14.04:LTS: linux-azure, Ubuntu:Pro:14.04:LTS: linux-lts-xenial, Ubuntu:Pro:16.04:LTS: linux, Ubuntu:Pro:16.04:LTS: linux-aws, 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 and 171 more

In the Linux kernel, the following vulnerability has been resolved: x86/hyperv: Disable IBT when hypercall page lacks ENDBR instruction On hardware that supports Indirect Branch Tracking (IBT), Hyper-V VMs with ConfigVersion 9.3 or later support IBT in the guest. However, current versions of Hyper-V have a bug in that there's not an ENDBR64 instruction at the beginning of the hypercall page. Since hypercalls are made with an indirect call to the hypercall page, all hypercall attempts fail with an exception and Linux panics. A Hyper-V fix is in progress to add ENDBR64. But guard against the Linux panic by clearing X86_FEATURE_IBT if the hypercall page doesn't start with ENDBR. The VM will boot and run without IBT. If future Linux 32-bit kernels were to support IBT, additional hypercall page hackery would be needed to make IBT work for such kernels in a Hyper-V VM.