gamlastan

A comprehensive Rust SAML 2.0 library built on zero-copy XML parsing. The library implements the full SAML 2.0 specification with errata corrections and passes the Italian SPID (Sistema Pubblico di Identita Digitale) conformance test suite (263/263 tests).

The plan is to become Rust equivalent of pysaml2 project. We will not be 100% compatible, but will try to close the gap. We thank the amazing maintainers of the pysaml2 project for maintaining the stack for the community.

The workspace requires Rust 1.88 or later.

The unreleased 0.10 series uses uppsala 0.12, bergshamra 0.11 and kryptering 0.7. Consumers that exchange XML documents, keys or signers with gamlastan must use matching versions, or use the re-exports in gamlastan::xml and gamlastan::crypto. The crypto stack uses the RustCrypto provider with legacy, post-quantum and PKCS#11 support; the SAML algorithm policy still controls which algorithms are accepted.

Workspace Structure

Crate	Description
gamlastan	Core SAML 2.0 library: types, XML, crypto, metadata, bindings, security, profiles
gamlastan-actix	actix-web integration (extractors, responders, handlers, middleware)
gamlastan-mdq	Metadata Query Protocol (MDQ) client: fetch entity metadata on demand, verify, and cache

The gamlastan crate contains the following modules:

Module	Description
core	Core SAML 2.0 types (Issuer, NameID, Assertions, StatusCode, Conditions, etc.)
xml	XML serialization/deserialization via uppsala
crypto	Cryptographic operations (signing, verification) via bergshamra
metadata	SAML metadata types, SPID extensions, caching, and validation
bindings	HTTP Redirect, POST, Artifact, SOAP, PAOS bindings and RelayState handling
attribute_map	Attribute name conversion between wire names and local names (pysaml2 attribute_maps), with shipped maps
idp	IdP side: release policy, entity categories, NameID store, authn broker, assertion store, and the orchestrator that assembles responses
security	35-check assertion validator, replay cache, clock skew handling
profiles	Web Browser SSO (SP + IdP), SLO, ECP, artifact resolution, name ID management, Sweden Connect deployment profile

Deployment Profiles

In addition to the core SAML 2.0 profiles, gamlastan ships national deployment profiles that layer restrictions and extensions on Web Browser SSO:

Profile	Module	Description
Italian SPID	(built into core, metadata, security)	Italian public digital identity system; validated by the SPID conformance suite (see below)
Sweden Connect	profiles::swedenconnect	Deployment Profile for the Swedish eID Framework (Sweden Connect / DIGG)

The swedenconnect module implements the Swedish eID Framework as a restriction and extension of Web Browser SSO, covering:

• Levels of Assurance -- the LevelOfAssurance enum, exact-comparison RequestedAuthnContext building, and the section 6.3.4 LoA matching check.
• Deployment configuration -- SwedenConnectConfig yields a profile-correct SecurityConfig (<= 1 minute clock skew, signed + encrypted responses, Destination/Recipient checks).
• Metadata extensions -- mdui:UIInfo, mdattr:EntityAttributes (entity categories + assurance certification), shibmd:Scope, and idpdisc:DiscoveryResponse.
• Principal selection -- the psc:PrincipalSelection request extension and psc:RequestedPrincipalSelection metadata extension.
• Authentication for Signature -- the csig:SignMessage and sap:SADRequest request extensions (section 7).
• SP-side request/response -- AuthnRequest construction (section 5) and Response processing: decrypt, signature verification, LoA match, structural checks (section 6).
• IdP-side responses -- Response and error construction (sections 6 and 6.4).

The ordinary Web Browser SSO profile is fully covered. Holder-of-key is supported at the metadata/constant and SubjectConfirmation-method level; the mutual-TLS transport requirement is a deployment concern outside the library. The DSS/SAP SignRequest/SignResponse envelope and SAD verification are out of scope.

Building an IdP

gamlastan::idp::orchestrator composes the IdP primitives into the Web Browser SSO response flow. The application supplies the authenticated subject and its attributes; the engine decides ForceAuthn, IsPassive and RequestedAuthnContext (check_request), derives the NameID, releases attributes, and signs the response (create_authn_response), or answers with a signed protocol error (create_denial_response). Identity and assertion stores are traits (IdentityStore, AssertionStore), with in-memory implementations and a conformance suite, idp::ident::conformance, to check a database-backed one.

gamlastan-actix provides ready handlers on top of it (AuthnSubjectCallback), and example-idp is a runnable reference. Several defaults follow pysaml2 and are permissive (attribute release, accepted NameID formats); the idp::orchestrator module docs list the ones to review before production, and ADR 0045 has the design.

Performance

See the SAML pipeline benchmark guide for reproducible native parsing and verification measurements and their limitations.

Security

gamlastan is built to fail closed against the SAML attack classes catalogued in samlattacks.md. The enforced controls — signature binding against XML Signature Wrapping, request correlation, ready-handler trust boundaries, and fail-closed key extraction and input validation — are documented in docs/security-hardening.md, with the rationale for each decision captured in the Architecture Decision Records.

License

BSD-2-Clause