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Rust SIP — specification references

Authoritative references for in-process Authenticode “SIP logic” (digest scope, PKCS#7 embedding rules). Link-only; do not paste non-open licensed SDK headers verbatim.

PE / COFF

PKCS#7 / Authenticode OIDs (checklist)

  • ContentType SignedData: 1.2.840.113549.1.7.2
  • SPC_INDIRECT_DATA_OBJID: 1.3.6.1.4.1.311.2.1.4
  • Digest algorithms: SHA-256 2.16.840.1.101.3.4.2.1, SHA-1 1.3.14.3.2.26
  • RFC3161 countersignature (Tier 1b): nested PKCS#7 / CMS timestamp token

Implementation notes

  • PE Authenticode digest in this repo delegates to the authenticode crate (google/authenticode-rs) (authenticode_digest), using object PeFile32 / PeFile64 as PeTrait inputs. For tooling and future page-hash alignment, pe_authenticode_digest_file_ranges (psign-sip-digest pe_digest) returns the ordered list of file byte ranges that participate in that digest (validated by unit tests against pe_authenticode_digest).
  • PKCS#7 encode + RSA signing for a standalone Rust signer path is not complete yet; see rust-sip-architecture.md.

PE image digest vs SPC_PE_IMAGE_PAGE_HASHES

The subject digest embedded in SpcIndirectDataContent follows authenticode_digest: it hashes the PE in several disjoint file ranges — skipping the optional-header checksum DWORD, skipping the security directory slot in the data directory, hashing sections in ascending virtual/raw start order, then any trailing file tail excluding the WIN_CERTIFICATE table. See authenticode-rs authenticode_digest.rs.

Page-hash authenticated attributes (1.3.6.1.4.1.311.2.3.1 / .2) carry a separate flat table of (end_offset, digest) pairs. Native WinVerifyTrust /ph validates those entries against PE bytes with rules that do not reduce to “hash contiguous raw slices from offset 0”. The portable CLI command psign-tool portable verify-pe-page-hashes implements an experimental contiguous raw-file model only — closing Tier 1c parity requires matching WINTRUST/CryptSIP page-boundary and exclusion semantics (or reusing their outputs via FFI on Windows).

The subject-digest disjoint ranges are enumerated in-code as pe_authenticode_digest_file_ranges for tooling (same segment order as authenticode_digest).

Writable working directories

Binaries under Program Files are often not writable side-by-side with caches or databases some tools create. If a workflow fails with access denied, copy signtool.exe / WINTRUST.dll (or other inputs) to %TEMP% or another user-writable directory and run against that path.

WINTRUST PE SIP: page hashes and SPC_LINK

WintrustSetDefaultIncludePEPageHashes controls the default inclusion of PE page-hash authenticated attributes (related to native /ph and SIGNTOOL_PAGE_HASHES).

SignerSignEx dwFlags semantics flow through SIP_SUBJECTINFO.dwFlags. The inbox PE SIP chooses whether to emit page-hash attributes (CreatePageHashesAttribute) vs a simpler SPC_LINK encoding:

  • If SPC_EXC_PE_PAGE_HASHES_FLAG (0x10) is clear and (SPC_INC_PE_PAGE_HASHES_FLAG (0x100) is set or the process default from WintrustSetDefaultIncludePEPageHashes is on), the SIP builds page-hash authenticated attributes and the encoded SPC_LINK path includes that blob (dwLinkChoice == 2 in Microsoft’s layout).
  • Otherwise the SIP takes the branch without that serialized page-hash payload (dwLinkChoice == 3).

Portable Rust signing needs the same precedence (explicit exclude wins; else explicit include or process default) to match signtool.exe / SignerSignEx3 when page hashing is enabled.

SignerSignEx3 and SIP glue

SignerSignEx3 routes subject hashing and PKCS#7 embedding through the registered CryptSIP implementation for the file type.

MSIX / APPX / bundles — APPX_SIP_CLIENT_DATA

Microsoft’s sample for programmatic app-package signing requires pSipData to point at APPX_SIP_CLIENT_DATA, whose pSignerParams references the same SIGNER_SIGN_EX2_PARAMS-shaped aggregate SignerSignEx3 uses (with pSipData inside that aggregate pointing back at APPX_SIP_CLIENT_DATA — a deliberate cycle).

AppxSip expects SIP_SUBJECTINFO.pClientData to reference valid APPX_SIP_CLIENT_DATA (initialized along AppxSipPutSignedDataMsg); null or invalid client data yields APPX_E_MISSING_PUBLIC_KEY_OR_REQUIRED_DATA (0x80080209). mssign32 passes SignerSignEx3 pSipData through to pClientData for the SIP call chain.

psign (src/win/sign_core.rs) passes this APPX_SIP_CLIENT_DATA + SIGNER_SIGN_EX2_PARAMS layout for every CodeSignFormat::MsixFamily SignerSignEx3 call (embedded and decoupled /dlib + /dmdf — digest callbacks use the separate pDigestSignInfo parameter).

Other optional SignerSignEx3 parameters

  • pCryptoPolicy (PCERT_STRONG_SIGN_PARA) — NULL in-tree; strong-sign policy checks from CERT_STRONG_SIGN_PARA are not applied by psign on sign.
  • pDigestSignInfo — used only for decoupled /dlib + /dmdf signing; standard embedded signing leaves this NULL except that path.