linux-kernel - Re: [PATCH v3] efi: Do not import certificates from UEFI Secure Boot for T2 Macs

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Message-ID: <522D95FA-C088-4488-B240-1E97274CEB74@live.com>
Date:   Wed, 23 Feb 2022 13:49:29 +0000
From:   Aditya Garg <gargaditya08@...e.com>
To:     David Laight <David.Laight@...LAB.COM>
CC:     Ard Biesheuvel <ardb@...nel.org>,
        Matthew Garrett <mjg59@...f.ucam.org>,
        Jeremy Kerr <jk@...abs.org>,
        "joeyli.kernel@...il.com" <joeyli.kernel@...il.com>,
        "zohar@...ux.ibm.com" <zohar@...ux.ibm.com>,
        "jmorris@...ei.org" <jmorris@...ei.org>,
        "eric.snowberg@...cle.com" <eric.snowberg@...cle.com>,
        "dhowells@...hat.com" <dhowells@...hat.com>,
        "jlee@...e.com" <jlee@...e.com>,
        "James.Bottomley@...senpartnership.com" 
        <James.Bottomley@...senPartnership.com>,
        "jarkko@...nel.org" <jarkko@...nel.org>,
        "mic@...ikod.net" <mic@...ikod.net>,
        "dmitry.kasatkin@...il.com" <dmitry.kasatkin@...il.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
        "linux-security-module@...r.kernel.org" 
        <linux-security-module@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "keyrings@...r.kernel.org" <keyrings@...r.kernel.org>,
        "linux-integrity@...r.kernel.org" <linux-integrity@...r.kernel.org>,
        Orlando Chamberlain <redecorating@...tonmail.com>,
        Aun-Ali Zaidi <admin@...eit.net>
Subject: Re: [PATCH v3] efi: Do not import certificates from UEFI Secure Boot
 for T2 Macs



> On 10-Feb-2022, at 4:17 PM, Aditya Garg <gargaditya08@...e.com> wrote:
> 
> From: Aditya Garg <gargaditya08@...e.com>
> 
> 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@...r.kernel.org
> Signed-off-by: Aditya Garg <gargaditya08@...e.com>
> ---
> v2 :- Reduce code size of the table.
> V3 :- Close the brackets which were left open by mistake.
> .../platform_certs/keyring_handler.h          |  8 ++++
> security/integrity/platform_certs/load_uefi.c | 48 +++++++++++++++++++
> 2 files changed, 56 insertions(+)
> 
Hi

May I have any updates on this patch?