Patina: Fix RAW FFS file handling and harden section parsing

[vineelko]

Description

1. Handle RAW File types:

   • The current implementation tries to produce sections irrespective of the file
     type. This do not hold true for RAW file types. As per PI spec below,

     The file type EFI_FV_FILETYPE_RAW denotes a file that does not contain
     sections and is treated as a raw data file. The consumer of this type of
     file must have a priori knowledge of its format and content. Because there
     are no sections, there are no construction rules.

   • Trying to decode the body of these files as Section header can result in
     incorrect parsing.

   Fixes the following bug:

   [ INFO]: \patina\sdk\patina\src\pi\serializable\serializable_fv.rs@078: Parsing FV: d2c29ba7-3809-480f-9c3d-de389c61425a
   [ INFO]: \patina\sdk\patina\src\pi\serializable\serializable_fv.rs@089:     Parsing file: 197db236-f856-4924-90f8-cdf12fb875f3
   [ INFO]: \patina\sdk\patina\src\pi\fw_fs.rs@801: Section type 0x0 unrecognized 4 1, treating as opaque with no metadata
   [ERROR]: dxe_readiness_capture\src\lib.rs@031: panicked at \patina\sdk\patina\src\pi\fw_fs.rs:805:56:
   [ERROR]: dxe_readiness_capture\src\lib.rs@031: slice index starts at 4 but ends at 1
   

2. Improve safety in FFS section parsing by replacing direct slice indexing with
   bounds checked get() calls and proper error propagation when buffers are
   malformed. General code cleanup.

---

• Impacts functionality?
• Impacts security?
• Breaking change?
• Includes tests?
• Includes documentation?

How This Was Tested

Booted to UEFI Shell on Q35

Integration Instructions

NA

[patina-automation]

ℹ️ QEMU Validation Skipped - PR Merged

The Patina QEMU PR validation workflow did not run because the PR was merged before validation started.

Workflow run: https://github.com/OpenDevicePartnership/patina/actions/runs/22963784661

Note: Previous results are available in this comment's edit history.

This comment was automatically generated by the Patina QEMU PR Validation Post workflow.

[codecov]

Codecov Report

❌ Patch coverage is 96.87500% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
sdk/patina/src/pi/fw_fs.rs	96.77%	2 Missing ⚠️

📢 Thoughts on this report? Let us know!

[vineelko]

Please hold on this PR, Got the fv from IDC folks, It looks like there is more to the actual bug. I will notify once I finished root causing the issue.

[vineelko]

As mentioned before, the section parsing failed with below error(Section Type 0x0).

[ INFO]: E:\repos\patina\sdk\patina\src\pi\serializable\serializable_fv.rs@078: Parsing FV: d2c29ba7-3809-480f-9c3d-de389c61425a
[ INFO]: E:\repos\patina\sdk\patina\src\pi\serializable\serializable_fv.rs@089:     Parsing file: 197db236-f856-4924-90f8-cdf12fb875f3
[ INFO]: E:\repos\patina\sdk\patina\src\pi\fw_fs.rs@801: Section type 0x0 unrecognized 4 1, treating as opaque with no metadata
[ERROR]: dxe_readiness_capture\src\lib.rs@031: panicked at E:\repos\patina\sdk\patina\src\pi\fw_fs.rs:805:56:
[ERROR]: dxe_readiness_capture\src\lib.rs@031: slice index starts at 4 but ends at 1

The parsing of sections in the section iterator required few fixes, especially around handling SectionType::ALL to ensure parity with the C UEFI implementation, where the entire body is returned.

However, after looking at the FV, The current implementation attempts to produce sections regardless of the file type. This assumption does not hold true for RAW file types. According to the PI specification below,

Trying to decode the body of these files as Section header can result in incorrect parsing. This is addressed in the latest iteration.

PR is up for review.

[makubacki]

@vineelko, the PR title gives the impression this is a broad FFS section parsing issue and I think it really comes down to RAW files and some other cleanup. If that's the case, could you consider updating the title?

[vineelko]

Fixed the title Michael.