MGASA-2021-0117

This kernel update is based on upstream 5.10.20 and fixes at least the following security issues:

A NULL pointer dereference flaw was found in the Linux kernel's GPU Nouveau driver functionality in versions prior to 5.12-rc1 in the way the user calls ioctl DRM_IOCTL_NOUVEAU_CHANNEL_ALLOC. This flaw allows a local user to crash the system. (CVE-2020-25639).

An issue was discovered in the Linux kernel through 5.11.3, as used with Xen PV. A certain part of the netback driver lacks necessary treatment of errors such as failed memory allocations (as a result of changes to the handling of grant mapping errors). A host OS denial of service may occur during misbehavior of a networking frontend driver. NOTE: this issue exists because of an incomplete fix for CVE-2021-26931. (CVE-2021-28038 / XSA-367)

An issue was discovered in the Linux kernel 5.9.x through 5.11.3, as used with Xen. In some less-common configurations, an x86 PV guest OS user can crash a Dom0 or driver domain via a large amount of I/O activity. The issue relates to misuse of guest physical addresses when a configuration has CONFIG_XEN_UNPOPULATED_ALLOC but not CONFIG_XEN_BALLOON_MEMORY_HOTPLUG. (CVE-2021-28039 / XSA-369)

It also adds a critical fix for filesystem level corruption:

• on setups with swapfiles on filesystems sitting on top of brd, zram, btt or pmem, then when the system starts to swap out pages, at which point it corrupts filesystem blocks that don't belong to the swapfile.

It also adds the following fixes:

• Input: elan_i2c - add new trackpoint report type 0x5F
• Input: elantech - fix protocol errors for some trackpoints
• net: usb: qmi_wwan: support ZTE P685M modem
• tty: fix up iterate_tty_read() EOVERFLOW handling
• tty: fix up hung_up_tty_read() conversion
• tty: clean up legacy leftovers from n_tty line discipline
• tty: teach n_tty line discipline about the new "cookie continuations"
• tty: teach the n_tty ICANON case about the new "cookie continuations" too
• x86_64-server config:
  • enable NUMA balancing
  • make CONNECTOR builtin to enable PROC_EVENTS (mga#28312)
  • support 512 cores/threads

For other upstream fixes, see the referenced changelogs.