feat: add ELF and MCUboot signing support with format abstraction (Phase 2)#55
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feat: add ELF and MCUboot signing support with format abstraction (Phase 2)#55
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…ase 2) Introduce format-agnostic signing architecture and initial support for ELF binary and MCUboot firmware image signing. New modules: - format/mod.rs: FormatType enum, SignableArtifact trait, format detection with polyglot file validation (SC-15, AS-17) - format/elf.rs: ELF parser with section header consistency validation (SC-12), overlap detection (UCA-13), resource bounds (UCA-17), and full-file hashing (AS-14 defense) - format/mcuboot.rs: MCUboot parser with independent image size verification (SC-13, UCA-14, AS-15) CLI changes: - New --format flag on sign and verify subcommands (wasm|elf|mcuboot) - Format consistency validation (declared vs detected magic bytes) - ELF signing produces detached .sig file - MCUboot signing embeds signature in TLV trailer Architecture: - SignableArtifact trait: compute_hash, attach_signature, detach_signature, serialize, content_bytes — shared interface for all formats - Domain separation per format: "wasmsig", "elfsig", "mcubootsig" - Content type IDs: WASM=0x01, ELF=0x02, MCUboot=0x03 - Ed25519 signing core unchanged — format handlers only do parsing/hashing 26 new tests covering format detection, ELF parsing, MCUboot parsing, resource bounds, and section overlap validation. Implements: FEAT-2 Refs: SC-12, SC-13, SC-15, UCA-13, UCA-14, UCA-17, AS-14, AS-15, AS-17 Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Complete the requirement → design → implementation → verification chain for ELF and MCUboot signing: Requirements: CR-12 (ELF section validation), CR-13 (MCUboot size verification), CR-14 (explicit format flag), CR-15 (resource bounds), CR-16 (domain-separated signing) Design: CD-13 (SignableArtifact trait), CD-14 (ELF module), CD-15 (MCUboot module), CD-16 (format detection) Implementation: CI-1 (format/mod.rs), CI-2 (format/elf.rs), CI-3 (format/mcuboot.rs) Verification: CV-12 (ELF tests), CV-13 (MCUboot tests), CV-14 (format detection tests), CV-15 (fuzz targets, draft) Total: 305 artifacts, 95.1% traceability coverage. Implements: FEAT-2 Refs: SC-12, SC-13, SC-15, CR-12, CR-13, CR-14, CR-15, CR-16 Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
…t CLI Used rivet add/link/modify CLI commands to: - Create REQ-11 (ELF and MCUboot E2E test requirement) - Link REQ-3, REQ-4 to FEAT-2 (resolving orphan warnings) - Link REQ-11 to FEAT-2 Refs: FEAT-2, REQ-3, REQ-4, REQ-11 Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Configure synth as a rivet external and add traces-to links from sigil's binary signing artifacts to synth's ELF backend and reproducibility requirements: sigil:SC-12 → synth:ARCH-003 (ELF section validation depends on ELF output) sigil:H-15 → synth:ARCH-003, synth:NFR-002 (transcoding hazard) sigil:L-7 → synth:L-6, synth:ARCH-003 (attestation chain continuity) sigil:SC-14 → synth:FR-002, synth:VER-001 (chain maintenance) sigil:DF-13 → synth:ARCH-003, synth:NFR-002 (attestation data flow) Reverse links added in synth repo: synth:ARCH-003 → sigil:CR-12, sigil:CD-14, sigil:FEAT-2 synth:NFR-002 → sigil:L-7, sigil:SC-14 Refs: FEAT-2, SC-12, SC-14, H-15, L-7, DF-13 Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Summary
Phase 2 of the STPA-Sec implementation plan — extends sigil beyond WASM to sign ELF binaries and MCUboot firmware images.
New architecture
SignableArtifacttrait — format-agnostic interface:compute_hash,attach_signature,detach_signature,serializeFormatTypeenum —Wasm | Elf | Mcubootwith content type IDs, domain separation, and magic byte detectionELF signing (
format/elf.rs).sigfile) — proper ELF section embedding is future workMCUboot signing (
format/mcuboot.rs)ih_img_sizeheader (SC-13, UCA-14)CLI
Test plan
cargo test— 616 tests pass (26 new format tests)cargo build— clean compilation with#![forbid(unsafe_code)]🤖 Generated with Claude Code