Crate acdp_safe_http 

SSRF defenses for server-side cross-registry resolution (RFC-ACDP-0006 §7).

Single source of SSRF policy

This module is the single source of truth for ACDP’s SSRF policy across both the client and server features. The server-scoped path (crate::registry::safe_http) does not reimplement any of this — it only re-exports SsrfPolicy from here (see src/registry/safe_http.rs). Any change to blocked IP ranges, the HTTPS-only rule, redirect limits, or DNS-rebinding handling therefore applies to client and server alike; there is no second copy to keep in sync. Do not add a divergent implementation under registry/.

When a registry resolves a foreign acdp:// reference on behalf of a consumer, it must defend against attacker-supplied URIs that target the registry’s own internal network. This module implements the policy decisions enumerated by §7:

• §7.1 Reject loopback, RFC 1918 / 4193 private ranges, link-local, multicast, the AWS / GCP metadata endpoint (169.254.169.254), and the IPv6 equivalents.
• §7.2 HTTPS-only.
• §7.3 Response-size caps.
• §7.5 Maximum redirects, same-authority only.
• §7.6 DNS rebinding protection. [SsrfPolicy::pin_resolved_ip] resolves a hostname once, validates every returned IP, and returns a [SocketAddr] that the caller pins into reqwest::Client::builder().resolve(host, addr) — so the filter and the connection use the same IP, defeating a hostile DNS server flipping the answer between the two. Per §7.1 the resolution is rejected outright if any returned IP is forbidden — a public answer cannot mask a private one.

Structs

SsrfPolicy

SSRF policy applied to outbound HTTP requests.

SsrfRejection

A rejection produced by the classify_* SSRF checks: a stable SsrfReason discriminant plus a human-readable detail.

Enums

SsrfReason

Stable, machine-readable reason an SSRF check rejected a target.

Constants

MAX_CONTEXT_BYTES

Maximum body bytes for a context retrieval (RFC-ACDP-0006 §7.3).

MAX_METADATA_BYTES

Maximum body bytes for capabilities or DID documents (§7.3).

MAX_REDIRECTS

Maximum HTTP redirects to follow (§7.5).