Add static memory and dynamic memory

[aidangarske]

Description

Add static memory (zero-malloc) support with compile-time toggle

• Add --enable-dynamic-mem configure option; default is static (no malloc)
• Guard wolfSPDM_New() behind WOLFSPDM_DYNAMIC_MEMORY define
• Refactor Init/New/Free: Init does XMEMSET clean slate, New calls Init
  and sets isDynamic flag, Free uses wc_ForceZero and conditional XFREE
• Add wolfSPDM_InitStatic() and WOLFSPDM_CTX_STATIC_SIZE for consumers
  to allocate context inline without heap allocation
• Generate wolfspdm/options.h from config.h so consumers (e.g. wolfTPM)
  pick up WOLFSPDM_DYNAMIC_MEMORY and WOLFSPDM_NUVOTON defines
• Add options.h to .gitignore (auto-generated build artifact)
• Update unit_test.c and test_spdm.c for both static and dynamic paths

Tested across all 4 configurations:
dynamic-mem + spdm-emu: PASS --emu
static + spdm-emu: PASS --emu
dynamic-mem + Nuvoton: PASS (5/5)
static + Nuvoton: PASS (5/5)

• Update CI tests for new --enable-dynamic-mem

[Copilot]

Pull request overview

This PR adds compile-time toggleable static memory (zero-malloc) support to wolfSPDM, making dynamic memory allocation opt-in rather than default. The primary goal is to enable zero-malloc operation for embedded systems while maintaining backward compatibility for users who prefer dynamic allocation.

Changes:

• Added --enable-dynamic-mem configure option (default: static/no malloc) to control memory allocation strategy
• Refactored context management: wolfSPDM_Init() now does clean-slate initialization, wolfSPDM_New() is guarded behind WOLFSPDM_DYNAMIC_MEMORY define, and wolfSPDM_Free() handles both static and dynamic contexts
• Introduced auto-generated wolfspdm/options.h to propagate build configuration to downstream consumers (e.g., wolfTPM)
• Optimized stack usage by reducing oversized local buffers and eliminating redundant copies in encryption path
• Updated CI workflows to test all combinations of build configurations (2 OS × 2 debug × 2 nuvoton × 2 dynamic-mem = 16 test configurations)

Reviewed changes

Copilot reviewed 13 out of 14 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
wolfspdm/spdm.h	Added options.h include, updated API documentation for static/dynamic usage patterns, added WOLFSPDM_CTX_STATIC_SIZE constant, conditionally compiled wolfSPDM_New()
src/spdm_context.c	Refactored Init/New/Free functions: Init does XMEMSET clean slate, New calls Init and sets isDynamic flag, Free uses wc_ForceZero and conditional XFREE based on isDynamic
src/spdm_internal.h	Added isDynamic flag to WOLFSPDM_CTX, included memory.h for wc_ForceZero
src/spdm_session.c	Reduced local buffer sizes from oversized allocations to more precise sizes (e.g., VERSION rxBuf: 64→32, CAPABILITIES: 32→24)
src/spdm_secured.c	Removed redundant ciphertext buffer, encrypt directly into output buffer to save ~4KB stack space, reduced buffer overhead from +64 to +48 bytes
src/spdm_crypto.c	Reduced derSig buffer from 128 to 104 bytes (P-384 DER signature max size)
test/unit_test.c	Updated tests to use stack-allocated contexts for static path, conditionally compiled test_context_new_free() behind WOLFSPDM_DYNAMIC_MEMORY
test/test_spdm.c	Changed to use static buffer (g_ctxBuf) with wolfSPDM_InitStatic() instead of wolfSPDM_New()
configure.ac	Added --enable-dynamic-mem option with default=no
config.h.in	Added WOLFSPDM_DYNAMIC_MEMORY configuration define
Makefile.am	Added build rule to generate wolfspdm/options.h from config.h, added options.h to installed headers and CLEANFILES
.gitignore	Added wolfspdm/options.h to ignore list
.github/workflows/build-test.yml	Added dynamic-mem to test matrix (16 total configurations)
.github/workflows/memory-check.yml	Added dynamic-mem to Valgrind test matrix

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