53 lines
1.4 KiB
Go
53 lines
1.4 KiB
Go
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package auth
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import (
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"context"
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"fmt"
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"github.com/lestrrat-go/jwx/v2/jwt"
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)
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// Validator validates a bearer JWT's signature, issuer, audience, and
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// exp/nbf claims against a cached JWKS (design.md §8).
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type Validator struct {
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Issuer string
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Audience string
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Keys KeySetProvider
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}
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// NewValidator does the OIDC discovery + JWKS cache setup and returns a
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// ready-to-use Validator. Fails fast if the discovery document or initial
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// JWKS fetch is unreachable.
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func NewValidator(ctx context.Context, issuerURL, audience string) (*Validator, error) {
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doc, err := FetchDiscoveryDocument(ctx, issuerURL)
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if err != nil {
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return nil, fmt.Errorf("new validator: %w", err)
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}
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cache, err := NewJWKSCache(ctx, doc.JWKSURI)
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if err != nil {
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return nil, fmt.Errorf("new validator: %w", err)
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}
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return &Validator{Issuer: doc.Issuer, Audience: audience, Keys: cache}, nil
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}
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// Validate parses and verifies tokenString: signature against the current
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// JWKS, plus iss/aud/exp/nbf claims. Returns the parsed token on success.
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func (v *Validator) Validate(ctx context.Context, tokenString string) (jwt.Token, error) {
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set, err := v.Keys.Get(ctx)
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if err != nil {
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return nil, fmt.Errorf("validate: fetch key set: %w", err)
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}
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token, err := jwt.Parse(
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[]byte(tokenString),
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jwt.WithKeySet(set),
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jwt.WithValidate(true),
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jwt.WithIssuer(v.Issuer),
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jwt.WithAudience(v.Audience),
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)
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if err != nil {
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return nil, fmt.Errorf("validate: %w", err)
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}
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return token, nil
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}
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