96 lines
2.6 KiB
Go
96 lines
2.6 KiB
Go
package jwt
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import (
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"context"
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"fmt"
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"time"
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gojwt "github.com/dgrijalva/jwt-go"
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"github.com/influxdata/chronograf"
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)
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// Test if JWT implements Authenticator
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var _ chronograf.Authenticator = &JWT{}
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// JWT represents a javascript web token that can be validated or marshaled into string.
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type JWT struct {
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Secret string
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Now func() time.Time
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}
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// NewJWT creates a new JWT using time.Now; secret is used for signing and validating.
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func NewJWT(secret string) JWT {
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return JWT{
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Secret: secret,
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Now: time.Now,
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}
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}
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// Ensure Claims implements the jwt.Claims interface
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var _ gojwt.Claims = &Claims{}
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// Claims extends jwt.StandardClaims Valid to make sure claims has a subject.
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type Claims struct {
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gojwt.StandardClaims
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}
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// Valid adds an empty subject test to the StandardClaims checks.
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func (c *Claims) Valid() error {
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if err := c.StandardClaims.Valid(); err != nil {
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return err
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} else if c.StandardClaims.Subject == "" {
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return fmt.Errorf("claim has no subject")
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}
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return nil
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}
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// Authenticate checks if the jwtToken is signed correctly and validates with Claims.
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func (j *JWT) Authenticate(ctx context.Context, jwtToken string) (chronograf.Principal, error) {
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gojwt.TimeFunc = j.Now
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// Check for expected signing method.
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alg := func(token *gojwt.Token) (interface{}, error) {
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if _, ok := token.Method.(*gojwt.SigningMethodHMAC); !ok {
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return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
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}
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return []byte(j.Secret), nil
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}
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// 1. Checks for expired tokens
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// 2. Checks if time is after the issued at
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// 3. Check if time is after not before (nbf)
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// 4. Check if subject is not empty
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token, err := gojwt.ParseWithClaims(jwtToken, &Claims{}, alg)
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if err != nil {
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return "", err
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} else if !token.Valid {
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return "", err
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}
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claims, ok := token.Claims.(*Claims)
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if !ok {
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return "", fmt.Errorf("unable to convert claims to standard claims")
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}
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return chronograf.Principal(claims.Subject), nil
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}
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// Token creates a signed JWT token from user that expires at Now + duration
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func (j *JWT) Token(ctx context.Context, user chronograf.Principal, duration time.Duration) (string, error) {
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// Create a new token object, specifying signing method and the claims
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// you would like it to contain.
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now := j.Now().UTC()
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claims := &Claims{
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gojwt.StandardClaims{
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Subject: string(user),
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ExpiresAt: now.Add(duration).Unix(),
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IssuedAt: now.Unix(),
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NotBefore: now.Unix(),
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},
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}
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token := gojwt.NewWithClaims(gojwt.SigningMethodHS256, claims)
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// Sign and get the complete encoded token as a string using the secret
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return token.SignedString([]byte(j.Secret))
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}
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