From: Mimi Zohar <zohar@linux.ibm.com>
To: Aditya Garg <gargaditya08@live.com>,
"jarkko@kernel.org" <jarkko@kernel.org>,
"dmitry.kasatkin@gmail.com" <dmitry.kasatkin@gmail.com>,
"jmorris@namei.org" <jmorris@namei.org>,
"serge@hallyn.com" <serge@hallyn.com>,
"ast@kernel.org" <ast@kernel.org>,
"daniel@iogearbox.net" <daniel@iogearbox.net>,
"andrii@kernel.org" <andrii@kernel.org>,
"kafai@fb.com" <kafai@fb.com>,
"songliubraving@fb.com" <songliubraving@fb.com>,
"yhs@fb.com" <yhs@fb.com>,
"john.fastabend@gmail.com" <john.fastabend@gmail.com>,
"kpsingh@kernel.org" <kpsingh@kernel.org>
Cc: "linux-integrity@vger.kernel.org"
<linux-integrity@vger.kernel.org>,
"keyrings@vger.kernel.org" <keyrings@vger.kernel.org>,
"linux-security-module@vger.kernel.org"
<linux-security-module@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
Orlando Chamberlain <redecorating@protonmail.com>,
"admin@kodeit.net" <admin@kodeit.net>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH v5] efi: Do not import certificates from UEFI Secure Boot for T2 Macs
Date: Thu, 14 Apr 2022 09:30:42 -0400 [thread overview]
Message-ID: <9aca02b10ff179a8297b06df11bde4faa8a39650.camel@linux.ibm.com> (raw)
In-Reply-To: <E9C28706-2546-40BF-B32C-66A047BE9EFB@live.com>
On Wed, 2022-04-13 at 14:04 +0000, Aditya Garg wrote:
> From: Aditya Garg <gargaditya08@live.com>
>
> On Apple T2 Macs, when Linux reads the db and dbx efi variables to load
> UEFI Secure Boot certificates, a page fault occurs in Apple firmware
> code and EFI services are disabled with the following logs:
>
> 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 also occurs when some other variables are read (see examples below,
> there are many more), but only when these variables are read at an early
> stage like db and dbx are to load UEFI certs.
>
> BridgeOSBootSessionUUID-4d1ede05-38c7-4a6a-9cc6-4bcca8b38c14
> KEK-8be4df61-93ca-11d2-aa0d-00e098032b8c
>
> On these Macs, we skip reading the EFI variables for the UEFI certificates.
> As a result without certificates, secure boot signature verification fails.
> As these Macs have a non-standard implementation of secure boot that only
> uses Apple's and Microsoft's keys (users can't add their own), securely
> booting Linux was never supported on this hardware, so skipping it
> shouldn't cause a regression.
Based on your explanation, there seems to be two issues - inability to
read EFI variables, "users can't add their own" keys. Neither of which
mean "a non-standard implementation of secure boot". Please fix the
"cause" and "affect" in the patch description and comments.
thanks,
Mimi
next prev parent reply other threads:[~2022-04-14 13:45 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-10 10:49 [PATCH v3 RESEND] efi: Do not import certificates from UEFI Secure Boot for T2 Macs Aditya Garg
2022-04-12 12:32 ` Mimi Zohar
2022-04-12 14:13 ` Aditya Garg
2022-04-12 15:13 ` Mimi Zohar
2022-04-12 15:40 ` Aditya Garg
2022-04-12 16:38 ` Aditya Garg
2022-04-12 16:40 ` [PATCH v4] " Aditya Garg
2022-04-12 16:44 ` [PATCH v4 RESEND] " Aditya Garg
2022-04-12 17:16 ` Mimi Zohar
2022-04-13 14:03 ` Aditya Garg
2022-04-13 14:04 ` [PATCH v5] " Aditya Garg
2022-04-14 13:30 ` Mimi Zohar [this message]
2022-04-15 6:17 ` Aditya Garg
2022-04-15 6:19 ` [PATCH v6] " Aditya Garg
2022-04-15 16:26 ` Mimi Zohar
2022-04-15 17:02 ` Aditya Garg
2022-04-15 17:02 ` [PATCH v7] " Aditya Garg
2022-04-22 17:39 ` [PATCH v7 RESEND] " Aditya Garg
2022-05-13 15:24 ` [PATCH v7] " Mimi Zohar
2022-05-13 18:31 ` Aditya Garg
2022-05-15 12:41 ` Mimi Zohar
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