Add OAuth2 API scope registration and enforcement

Register v1 API scopes in coredata, advertise them in OIDC discovery and protected-resource metadata, show them on the consent screen, and enforce scope-to-action mapping in the IAM Authorizer before policy evaluation. Signed-off-by: Ludovic Vielle <ludovic@probo.com>
2026-06-15 17:33:15 +02:00
parent 25151fa089
commit 3ebb221a9b
56 changed files with 1918 additions and 290 deletions
--- a/pkg/iam/oauth2/id_token.go
+++ b/pkg/iam/oauth2/id_token.go
@@ -0,0 +1,108 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+package oauth2
+
+import (
+	"crypto/rsa"
+	"crypto/sha256"
+	"encoding/base64"
+	"time"
+
+	"go.probo.inc/probo/pkg/coredata"
+	"go.probo.inc/probo/pkg/gid"
+	"go.probo.inc/probo/pkg/uri"
+)
+
+type (
+	// SigningKey pairs an RSA private key with its key ID. All entries are
+	// published in the JWKS endpoint. Keys with Active set to true are
+	// used for signing new tokens; when multiple keys are active, the
+	// service round-robins between them.
+	SigningKey struct {
+		PrivateKey *rsa.PrivateKey
+		KID        string
+		Active     bool
+	}
+
+	IDTokenClaims struct {
+		Issuer        uri.URI               `json:"iss"`
+		Subject       string                `json:"sub"`
+		Audience      string                `json:"aud"`
+		ExpiresAt     int64                 `json:"exp"`
+		IssuedAt      int64                 `json:"iat"`
+		AuthTime      int64                 `json:"auth_time"`
+		Nonce         string                `json:"nonce,omitempty"`
+		AtHash        string                `json:"at_hash,omitempty"`
+		Email         string                `json:"email,omitempty"`
+		EmailVerified *bool                 `json:"email_verified,omitempty"`
+		Name          string                `json:"name,omitempty"`
+		Scope         coredata.OAuth2Scopes `json:"-"`
+	}
+
+	SigningKeys []SigningKey
+)
+
+// ComputeAtHash computes the at_hash claim value for an access token.
+// Per OIDC Core §3.1.3.6: left half of SHA-256 hash, base64url-encoded.
+func ComputeAtHash(accessToken string) string {
+	h := sha256.Sum256([]byte(accessToken))
+	return base64.RawURLEncoding.EncodeToString(h[:16])
+}
+
+func NewIDTokenClaims(
+	issuer uri.URI,
+	identityID gid.GID,
+	clientID gid.GID,
+	authTime time.Time,
+	scopes coredata.OAuth2Scopes,
+	nonce string,
+	accessToken string,
+	email string,
+	emailVerified bool,
+	fullName string,
+	ttl time.Duration,
+) *IDTokenClaims {
+	now := time.Now()
+
+	claims := &IDTokenClaims{
+		Issuer:    issuer,
+		Subject:   identityID.String(),
+		Audience:  clientID.String(),
+		ExpiresAt: now.Add(ttl).Unix(),
+		IssuedAt:  now.Unix(),
+		AuthTime:  authTime.Unix(),
+		Scope:     scopes,
+	}
+
+	if nonce != "" {
+		claims.Nonce = nonce
+	}
+
+	if accessToken != "" {
+		claims.AtHash = ComputeAtHash(accessToken)
+	}
+
+	for _, scope := range scopes {
+		switch scope {
+		case ScopeEmail:
+			claims.Email = email
+			claims.EmailVerified = &emailVerified
+		case ScopeProfile:
+			claims.Name = fullName
+		}
+	}
+
+	return claims
+}