forked from crewjam/saml
/
request_tracker_jwt.go
75 lines (66 loc) · 2.14 KB
/
request_tracker_jwt.go
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package samlsp
import (
"crypto/rsa"
"fmt"
"time"
"github.com/golang-jwt/jwt/v4"
"github.com/ZackaryWelch/saml"
)
var defaultJWTSigningMethod = jwt.SigningMethodRS256
// JWTTrackedRequestCodec encodes TrackedRequests as signed JWTs
type JWTTrackedRequestCodec struct {
SigningMethod jwt.SigningMethod
Audience string
Issuer string
MaxAge time.Duration
Key *rsa.PrivateKey
}
var _ TrackedRequestCodec = JWTTrackedRequestCodec{}
// JWTTrackedRequestClaims represents the JWT claims for a tracked request.
type JWTTrackedRequestClaims struct {
jwt.RegisteredClaims
TrackedRequest
SAMLAuthnRequest bool `json:"saml-authn-request"`
}
// Encode returns an encoded string representing the TrackedRequest.
func (s JWTTrackedRequestCodec) Encode(value TrackedRequest) (string, error) {
now := saml.TimeNow()
claims := JWTTrackedRequestClaims{
RegisteredClaims: jwt.RegisteredClaims{
Audience: jwt.ClaimStrings{s.Audience},
ExpiresAt: jwt.NewNumericDate(now.Add(s.MaxAge)),
IssuedAt: jwt.NewNumericDate(now),
Issuer: s.Issuer,
NotBefore: jwt.NewNumericDate(now), // TODO(ross): correct for clock skew
Subject: value.Index,
},
TrackedRequest: value,
SAMLAuthnRequest: true,
}
token := jwt.NewWithClaims(s.SigningMethod, claims)
return token.SignedString(s.Key)
}
// Decode returns a Tracked request from an encoded string.
func (s JWTTrackedRequestCodec) Decode(signed string) (*TrackedRequest, error) {
parser := jwt.Parser{
ValidMethods: []string{s.SigningMethod.Alg()},
}
claims := JWTTrackedRequestClaims{}
_, err := parser.ParseWithClaims(signed, &claims, func(*jwt.Token) (interface{}, error) {
return s.Key.Public(), nil
})
if err != nil {
return nil, err
}
if !claims.VerifyAudience(s.Audience, true) {
return nil, fmt.Errorf("expected audience %q, got %q", s.Audience, claims.Audience)
}
if !claims.VerifyIssuer(s.Issuer, true) {
return nil, fmt.Errorf("expected issuer %q, got %q", s.Issuer, claims.Issuer)
}
if !claims.SAMLAuthnRequest {
return nil, fmt.Errorf("expected saml-authn-request")
}
claims.TrackedRequest.Index = claims.Subject
return &claims.TrackedRequest, nil
}