Credentials issuable over unauthenticated (anonymous) sessions (§14)

[nficano]

Category: spec-conformance Severity: blocker
Location: src/Arcp.Runtime/Internal/JobSubmitFlow.fs:91-118
Spec: ARCP v1.1 §14

What

Spec §14: 'Runtimes MUST issue them [credentials] over authenticated, encrypted transports only'. If ArcpServerOptions.AllowAnonymousAuth=true and a Provisioner is also configured, an AnonymousPrincipal session can submit jobs and receive minted credentials. Nothing in ArcpServer constructor or JobSubmitFlow prevents this combination or short-circuits issuance for anonymous principals.

Evidence

let private issueCredentialsAsync (provisioner) (registry) (record: JobRecord) (ct) =
    task {
        let ctx: CredentialIssueContext = { JobId = record.JobId; Principal = record.Principal; Lease = record.Lease; LeaseConstraints = record.Constraints; ParentJobId = ... }
        try
            let! credentials = provisioner.IssueAsync(ctx, ct)
            for cred in credentials do do! registry.Track(record.JobId, cred)
            return Ok credentials
        with ...
    }

Proposed fix

In ArcpServer constructor invalidArg when AllowAnonymousAuth=true && Provisioner.IsSome. Additionally guard issueCredentialsAsync: if record.Principal is AnonymousPrincipal, return Ok [] (skip issuance) and never call the provisioner.

Acceptance criteria

• Constructing ArcpServer with AllowAnonymousAuth=true and a non-None Provisioner throws at startup; and an anonymous-authenticated session submitting a job never receives a non-empty credentials array.