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Groups > linux.kernel > #1530192
| From | Ard Biesheuvel <ard.biesheuvel@linaro.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 5/7] efi: Get the secure boot status [ver #3] |
| Date | 2016-11-25 13:50 +0100 |
| Message-ID | <sHo71-CC-57@gated-at.bofh.it> (permalink) |
| References | (3 earlier) <sHliN-7iy-11@gated-at.bofh.it> <sHlsu-7lD-25@gated-at.bofh.it> <sHnuh-m5-5@gated-at.bofh.it> <sHnND-wd-9@gated-at.bofh.it> <sHo70-CC-35@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 25 November 2016 at 12:35, David Howells <dhowells@redhat.com> wrote:
> Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>
>> Yes. In pre-2.6, DeployedMode is not a reserved name, and so it may be
>> possible for someone to slip in a DeployedMode=0 on a secure boot
>> enabled system to trick the kernel into thinking lockdown should be
>> disabled.
>
> How does one get the version number? Unfortunately, searching the document
> for 'version' doesn't help as every page has that in the footer:-/
>
There is a 'revision' field in the header ('hdr') of the EFI system
table, so something like
(sys_table_arg->hdr.revision >> 16) > 2 ||
((sys_table_arg->hdr.revision >> 16) == 2 &&
(sys_table_arg->hdr.revision & 0xffff) >= 6)
should do the trick I think
>> > + if (val == 1)
>> > + return 0;
>>
>> I think the logic is the wrong way around here. Secure Boot is enabled
>> if SecureBoot=1 and SetupMode=0, unless DeployedMode=0. So you should
>> return 0 here if val == 0, but only when running on 2.6 or later.
>
> Good point.
>
> David
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[PATCH 0/7] efi: Pass secure boot mode to kernel [ver #3] David Howells <dhowells@redhat.com> - 2016-11-23 14:00 +0100
[PATCH 2/7] x86/efi: Allow invocation of arbitrary runtime services [ver #3] David Howells <dhowells@redhat.com> - 2016-11-23 14:00 +0100
[PATCH 4/7] efi: Add SHIM and image security database GUID definitions [ver #3] David Howells <dhowells@redhat.com> - 2016-11-23 14:00 +0100
[PATCH 7/7] efi: Add EFI_SECURE_BOOT bit [ver #3] David Howells <dhowells@redhat.com> - 2016-11-23 14:00 +0100
[PATCH 1/7] efi: use typed function pointers for runtime services table [ver #3] David Howells <dhowells@redhat.com> - 2016-11-23 14:00 +0100
[PATCH 6/7] efi: Disable secure boot if shim is in insecure mode [ver #3] David Howells <dhowells@redhat.com> - 2016-11-23 14:00 +0100
[PATCH 5/7] efi: Get the secure boot status [ver #3] David Howells <dhowells@redhat.com> - 2016-11-23 14:00 +0100
Re: [PATCH 5/7] efi: Get the secure boot status [ver #3] James Bottomley <James.Bottomley@HansenPartnership.com> - 2016-11-24 20:50 +0100
Re: [PATCH 5/7] efi: Get the secure boot status [ver #3] David Howells <dhowells@redhat.com> - 2016-11-25 10:50 +0100
Re: [PATCH 5/7] efi: Get the secure boot status [ver #3] Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-11-25 11:00 +0100
Re: [PATCH 5/7] efi: Get the secure boot status [ver #3] David Howells <dhowells@redhat.com> - 2016-11-25 13:10 +0100
Re: [PATCH 5/7] efi: Get the secure boot status [ver #3] Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-11-25 13:30 +0100
Re: [PATCH 5/7] efi: Get the secure boot status [ver #3] David Howells <dhowells@redhat.com> - 2016-11-25 13:50 +0100
Re: [PATCH 5/7] efi: Get the secure boot status [ver #3] Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-11-25 13:50 +0100
Re: [PATCH 5/7] efi: Get the secure boot status [ver #3] David Howells <dhowells@redhat.com> - 2016-11-25 14:10 +0100
Re: [PATCH 5/7] efi: Get the secure boot status [ver #3] Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-11-25 14:30 +0100
Re: [PATCH 5/7] efi: Get the secure boot status [ver #3] David Howells <dhowells@redhat.com> - 2016-11-25 14:10 +0100
Re: [PATCH 5/7] efi: Get the secure boot status [ver #3] Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-11-25 15:00 +0100
Re: [PATCH 5/7] efi: Get the secure boot status [ver #3] David Howells <dhowells@redhat.com> - 2016-11-25 17:00 +0100
Re: [PATCH 5/7] efi: Get the secure boot status [ver #3] David Howells <dhowells@redhat.com> - 2016-11-25 18:00 +0100
Re: [PATCH 5/7] efi: Get the secure boot status [ver #3] David Howells <dhowells@redhat.com> - 2016-11-25 18:00 +0100
Re: [PATCH 5/7] efi: Get the secure boot status [ver #3] Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-11-25 18:00 +0100
[PATCH 3/7] arm/efi: Allow invocation of arbitrary runtime services [ver #3] David Howells <dhowells@redhat.com> - 2016-11-23 14:00 +0100
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