Aditya Garg 2ba7d24fa2 efi: Do not import certificates from UEFI Secure Boot
On T2 Macs, the secure boot is handled by the T2 Chip. If enabled, only
macOS and Windows are allowed to boot on these machines. Thus we need to
disable secure boot for Linux. If we boot into Linux after disabling
secure boot, if CONFIG_LOAD_UEFI_KEYS is enabled, EFI Runtime services
fail to start, with the following logs in dmesg

Call Trace:
 <TASK>
 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
 </TASK>
---[ 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

This patch prevents querying of these UEFI variables, since these Macs
seem to use a non-standard EFI hardware

Cc: stable@vger.kernel.org
Signed-off-by: Aditya Garg <gargaditya08@live.com>
Signed-off-by: Aun-Ali Zaidi <admin@kodeit.net>
2022-03-25 01:57:15 +00:00
2022-03-16 14:26:52 +01:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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