CVE-2022-49357 Information

Description

In the Linux kernel the following vulnerability has been resolved:

efi: Do not import certificates from UEFI Secure Boot for T2 Macs

On Apple T2 Macs when Linux attempts to read the db and dbx efi variables at early boot to load UEFI Secure Boot certificates a page fault occurs in Apple firmware code and EFI runtime services are disabled with the following logs:

[Firmware Bug]: Page fault caused by firmware at PA: 0xffffb1edc0068000 WARNING: CPU: 3 PID: 104 at arch/x86/platform/efi/quirks.c:735 efi_crash_gracefully_on_page_fault+0x50/0xf0 (Removed some logs from here) Call Trace: page_fault_oops+0x4f/0x2c0 ? search_bpf_extables+0x6b/0x80 ? search_module_extables+0x50/0x80 ? search_exception_tables+0x5b/0x60 kernelmode_fixup_or_oops+0x9e/0x110 __bad_area_nosemaphore+0x155/0x190 bad_area_nosemaphore+0x16/0x20 do_kern_addr_fault+0x8c/0xa0 exc_page_fault+0xd8/0x180 asm_exc_page_fault+0x1e/0x30 (Removed some logs from here) ? __efi_call+0x28/0x30 ? switch_mm+0x20/0x30 ? efi_call_rts+0x19a/0x8e0 ? process_one_work+0x222/0x3f0 ? worker_thread+0x4a/0x3d0 ? kthread+0x17a/0x1a0 ? process_one_work+0x3f0/0x3f0 ? set_kthread_struct+0x40/0x40 ? ret_from_fork+0x22/0x30 —[ end trace 1f82023595a5927f ]— efi: Froze efi_rts_wq and disabled EFI Runtime Services integrity: Couldn’t get size: 0x8000000000000015 integrity: MODSIGN: Couldn’t get UEFI db list efi: EFI Runtime Services are disabled! integrity: Couldn’t get size: 0x8000000000000015 integrity: Couldn’t get UEFI dbx list integrity: Couldn’t get size: 0x8000000000000015 integrity: Couldn’t get mokx list integrity: Couldn’t get size: 0x80000000

So we avoid reading these UEFI variables and thus prevent the crash.

Reference

https://git.kernel.org/stable/c/155ca952c7ca19aa32ecfb7373a32bbc2e1ec6eb https://git.kernel.org/stable/c/1f7264f0510f519b4e4f575a8f0579ea65e7592e https://git.kernel.org/stable/c/65237307f88f5200782ae7f243bdd385e37cde5d https://git.kernel.org/stable/c/b1cda6dd2c44771f042d65f0d17bec322ef99a0a https://git.kernel.org/stable/c/b34786b25d75f9c119696e6bdf3827f54ae3601b https://git.kernel.org/stable/c/c072cab98bac11f6ef9db640fb51834d9552e2e6