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SubjectRe: [PATCH v14 01/13] hp-bioscfg: Documentation
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Hi--

On 5/17/23 08:50, Jorge Lopez wrote:
> HP BIOS Configuration driver purpose is to provide a driver supporting
> the latest sysfs class firmware attributes framework allowing the user
> to change BIOS settings and security solutions on HP Inc.’s commercial
> notebooks.
>
> Many features of HP Commercial notebooks can be managed using Windows
> Management Instrumentation (WMI). WMI is an implementation of Web-Based
> Enterprise Management (WBEM) that provides a standards-based interface
> for changing and monitoring system settings. HP BIOSCFG driver provides
> a native Linux solution and the exposed features facilitates the
> migration to Linux environments.
>
> The Linux security features to be provided in hp-bioscfg driver enables
> managing the BIOS settings and security solutions via sysfs, a virtual
> filesystem that can be used by user-mode applications. The new
> documentation cover HP-specific firmware sysfs attributes such Secure
> Platform Management and Sure Start. Each section provides security
> feature description and identifies sysfs directories and files exposed
> by the driver.
>
> Many HP Commercial notebooks include a feature called Secure Platform
> Management (SPM), which replaces older password-based BIOS settings
> management with public key cryptography. PC secure product management
> begins when a target system is provisioned with cryptographic keys
> that are used to ensure the integrity of communications between system
> management utilities and the BIOS.
>
> HP Commercial notebooks have several BIOS settings that control its
> behaviour and capabilities, many of which are related to security.
> To prevent unauthorized changes to these settings, the system can
> be configured to use a cryptographic signature-based authorization
> string that the BIOS will use to verify authorization to modify the
> setting.
>
> Linux Security components are under development and not published yet.
> The only linux component is the driver (hp bioscfg) at this time.
> Other published security components are under Windows.
>

IMO it doesn't help to have this blurb repeated in each patch.

The commit message should describe what this patch does and why.

> Signed-off-by: Jorge Lopez <jorge.lopez2@hp.com>
>
> ---
> Based on the latest platform-drivers-x86.git/for-next
> ---
> .../testing/sysfs-class-firmware-attributes | 102 +++++++++++++++++-
> 1 file changed, 100 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-class-firmware-attributes b/Documentation/ABI/testing/sysfs-class-firmware-attributes
> index 4cdba3477176..f8d6c089228b 100644
> --- a/Documentation/ABI/testing/sysfs-class-firmware-attributes
> +++ b/Documentation/ABI/testing/sysfs-class-firmware-attributes
> @@ -22,6 +22,11 @@ Description:
> - integer: a range of numerical values
> - string
>
> + HP specific types
> + -----------------
> + - ordered-list - a set of ordered list valid values
> +
> +
> All attribute types support the following values:
>
> current_value:
> @@ -126,6 +131,22 @@ Description:
> value will not be effective through sysfs until this rule is
> met.
>
> + HP specific class extensions
> + ------------------------------
> +
> + On HP systems the following additional attributes are available:
> +
> + "ordered-list"-type specific properties:
> +
> + elements:
> + A file that can be read to obtain the possible
> + list of values of the <attr>. Values are separated using
> + semi-colon (``;``). The order individual elements are listed
> + according to their priority. An element listed first has the

I have trouble parsing "The order individual elements are list
according to their property."

> + highest priority. Writing the list in a different order to
> + current_value alters the priority order for the particular
> + attribute.
> +
> What: /sys/class/firmware-attributes/*/authentication/
> Date: February 2021
> KernelVersion: 5.11
> @@ -206,7 +227,7 @@ Description:
> Drivers may emit a CHANGE uevent when a password is set or unset
> userspace may check it again.
>
> - On Dell and Lenovo systems, if Admin password is set, then all BIOS attributes
> + On Dell, Lenovo and HP systems, if Admin password is set, then all BIOS attributes
> require password validation.
> On Lenovo systems if you change the Admin password the new password is not active until
> the next boot.

> @@ -364,3 +394,71 @@ Description:
> use it to enable extra debug attributes or BIOS features for testing purposes.
>
> Note that any changes to this attribute requires a reboot for changes to take effect.
> +
> +
> + HP specific class extensions - Secure Platform Manager (SPM)
> + --------------------------------
> +
> +What: /sys/class/firmware-attributes/*/authentication/SPM/kek
> +Date: March 29

Date: should be Month Year or Month Day Year according to other files
(although it is apparently not specified as far as my quick searching
found).

> +KernelVersion: 5.18
> +Contact: "Jorge Lopez" <jorge.lopez2@hp.com>
> +Description:
> + 'kek' Key-Encryption-Key is a write-only file that can be used to configure the
> + RSA public key that will be used by the BIOS to verify
> + signatures when setting the signing key. When written,
> + the bytes should correspond to the KEK certificate
> + (x509 .DER format containing an OU). The size of the
> + certificate must be less than or equal to 4095 bytes.
> +
> +What: /sys/class/firmware-attributes/*/authentication/SPM/sk
> +Date: March 29

Ditto.

> +KernelVersion: 5.18
> +Contact: "Jorge Lopez" <jorge.lopez2@hp.com>
> +Description:
> + 'sk' Signature Key is a write-only file that can be used to configure the RSA
> + public key that will be used by the BIOS to verify signatures
> + when configuring BIOS settings and security features. When
> + written, the bytes should correspond to the modulus of the
> + public key. The exponent is assumed to be 0x10001.
> +
> +What: /sys/class/firmware-attributes/*/authentication/SPM/status
> +Date: March 29

Ditto.

> +KernelVersion: 5.18
> +Contact: "Jorge Lopez" <jorge.lopez2@hp.com>
> +Description:
> + 'status' is a read-only file that returns ASCII text in JSON format reporting
> + the status information.
> +
> + "State": "not provisioned | provisioned | provisioning in progress ",
> + "Version": " Major. Minor ",
> + "Nonce": <16-bit unsigned number display in base 10>,
> + "FeaturesInUse": <16-bit unsigned number display in base 10>,
> + "EndorsementKeyMod": "<256 bytes in base64>",
> + "SigningKeyMod": "<256 bytes in base64>"
> +
> +What: /sys/class/firmware-attributes/*/attributes/Sure_Start/audit_log_entries
> +Date: March 29

Ditto.

> +KernelVersion: 5.18
> +Contact: "Jorge Lopez" <jorge.lopez2@hp.com>
> +Description:
> + 'audit_log_entries' is a read-only file that returns the events in the log.
> +
> + Audit log entry format
> +
> + Byte 0-15: Requested Audit Log entry (Each Audit log is 16 bytes)
> + Byte 16-127: Unused
> +
> +What: /sys/class/firmware-attributes/*/attributes/Sure_Start/audit_log_entry_count
> +Date: March 29

Ditto.

> +KernelVersion: 5.18
> +Contact: "Jorge Lopez" <jorge.lopez2@hp.com>
> +Description:
> + 'audit_log_entry_count' is a read-only file that returns the number of existing
> + audit log events available to be read. Values are separated using comma (``,``)
> +
> + [No of entries],[log entry size],[Max number of entries supported]
> +
> + log entry size identifies audit log size for the current BIOS version.
> + The current size is 16 bytes but it can be up to 128 bytes long in future BIOS
> + versions.

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