Message-ID: <CAOOmCE-9M6rJSC6Tcvts6Z=1k0t1nrK_9P02TVLfYnJu8yfgww@mail.gmail.com>
Date:   Thu, 18 May 2023 11:12:55 -0500
From:   Jorge Lopez <jorgealtxwork@...il.com>
To:     Randy Dunlap <rdunlap@...radead.org>
Cc:     hdegoede@...hat.com, platform-driver-x86@...r.kernel.org,
        linux-kernel@...r.kernel.org, thomas@...ch.de,
        ilpo.jarvinen@...ux.intel.com
Subject: Re: [PATCH v14 01/13] hp-bioscfg: Documentation

On Wed, May 17, 2023 at 6:42 PM Randy Dunlap <rdunlap@...radead.org> wrote:
>
> 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@...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."

I will update the text and provide a more comprehensive statement.
For instance...  "Values are separated using semi-colon (``;``) and
listed according to their priority."
>
> > +                                     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).

Date format will be changed to Month Year across the file.
Thank you.
>
> > +KernelVersion:       5.18
> > +Contact:     "Jorge Lopez" <jorge.lopez2@...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@...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@...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@...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@...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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