Rust wrapper: add wolfssl::wolfcrypt::kdf, wolfssl::wolfcrypt::prf

[holtrop]

Description

Rust wrapper: add wolfssl::wolfcrypt::kdf, wolfssl::wolfcrypt::prf

Testing

How did you test?

Checklist

• added tests
• updated/added doxygen
• updated appropriate READMEs
• Updated manual and documentation

[Copilot]

Pull Request Overview

This PR adds Rust wrapper modules for wolfCrypt's Key Derivation Function (KDF) and Pseudo Random Function (PRF) capabilities. The changes include new public API modules, test coverage, and refactoring of existing code to use consistent core::ptr::null* instead of std::ptr::null*.

• Adds wolfssl::wolfcrypt::kdf module with TLS 1.3 HKDF and SSH KDF functions
• Adds wolfssl::wolfcrypt::prf module for PRF operations with various hash algorithms
• Standardizes null pointer usage across the codebase to use core::ptr for better no_std compatibility

Reviewed Changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
wrapper/rust/wolfssl/src/wolfcrypt/kdf.rs	New module implementing TLS 1.3 HKDF extract/expand and SSH KDF wrappers
wrapper/rust/wolfssl/src/wolfcrypt/prf.rs	New module implementing PRF wrapper with support for multiple hash algorithms
wrapper/rust/wolfssl/tests/test_kdf.rs	Test cases for TLS 1.3 HKDF and SSH KDF functions
wrapper/rust/wolfssl/tests/test_prf.rs	Test case for PRF with SHA-384
wrapper/rust/wolfssl/src/wolfcrypt.rs	Exports the new kdf and prf modules
wrapper/rust/include.am	Adds new source and test files to build system
wrapper/rust/wolfssl/tests/test_hmac.rs	Updates to use SHA256::DIGEST_SIZE constant instead of raw FFI constant
wrapper/rust/wolfssl/tests/test_hkdf.rs	Updates to use SHA256::DIGEST_SIZE constant instead of raw FFI constant
wrapper/rust/wolfssl/src/wolfcrypt/hkdf.rs	Updates documentation examples to use SHA256::DIGEST_SIZE
wrapper/rust/wolfssl/src/wolfcrypt/sha.rs	Standardizes to use core::ptr::null_mut()
wrapper/rust/wolfssl/src/wolfcrypt/rsa.rs	Standardizes to use core::ptr::null_mut()
wrapper/rust/wolfssl/src/wolfcrypt/ecc.rs	Standardizes to use core::ptr::null_mut()
wrapper/rust/wolfssl/src/wolfcrypt/dh.rs	Standardizes to use core::ptr::null()
wrapper/rust/wolfssl/src/wolfcrypt/aes.rs	Standardizes to use core::ptr::null() and core::ptr::null_mut()
doc/dox_comments/header_files/hmac.h	Corrects documentation comment for wc_Tls13_HKDF_Expand_Label

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