drone/internal/auth/authn/token.go

111 lines
2.7 KiB
Go

// Copyright 2022 Harness Inc. All rights reserved.
// Use of this source code is governed by the Polyform Free Trial License
// that can be found in the LICENSE.md file for this repository.
package authn
import (
"errors"
"fmt"
"net/http"
"strings"
"github.com/harness/gitness/internal/auth"
"github.com/harness/gitness/internal/store"
"github.com/harness/gitness/internal/token"
"github.com/harness/gitness/types"
"github.com/dgrijalva/jwt-go"
)
var _ Authenticator = (*TokenAuthenticator)(nil)
/*
* Authenticates a user by checking for an access token in the
* "Authorization" header or the "access_token" form value.
*/
type TokenAuthenticator struct {
principalStore store.PrincipalStore
tokenStore store.TokenStore
}
func NewTokenAuthenticator(
principalStore store.PrincipalStore,
tokenStore store.TokenStore) *TokenAuthenticator {
return &TokenAuthenticator{
principalStore: principalStore,
tokenStore: tokenStore,
}
}
func (a *TokenAuthenticator) Authenticate(r *http.Request, caller APICaller) (*auth.Session, error) {
ctx := r.Context()
str := extractToken(r)
if len(str) == 0 {
return nil, ErrNoAuthData
}
var principal *types.Principal
var err error
claims := &token.JWTClaims{}
parsed, err := jwt.ParseWithClaims(str, claims, func(token_ *jwt.Token) (interface{}, error) {
principal, err = a.principalStore.Find(ctx, claims.PrincipalID)
if err != nil {
return nil, fmt.Errorf("failed to get principal for token: %w", err)
}
return []byte(principal.Salt), nil
})
if err != nil {
return nil, fmt.Errorf("parsing of JWT claims failed: %w", err)
}
if !parsed.Valid {
return nil, errors.New("parsed JWT token is invalid")
}
if _, ok := parsed.Method.(*jwt.SigningMethodHMAC); !ok {
return nil, errors.New("invalid HMAC signature for JWT")
}
// ensure tkn exists
tkn, err := a.tokenStore.Find(ctx, claims.TokenID)
if err != nil {
return nil, fmt.Errorf("failed to find token in db: %w", err)
}
// protect against faked JWTs for other principals in case of single salt leak
if principal.ID != tkn.PrincipalID {
return nil, fmt.Errorf("JWT was for principal %d while db token was for principal %d",
principal.ID, tkn.PrincipalID)
}
return &auth.Session{
Principal: *principal,
Metadata: &auth.TokenMetadata{
TokenType: tkn.Type,
TokenID: tkn.ID,
Grants: tkn.Grants,
},
}, nil
}
func extractToken(r *http.Request) string {
bearer := r.Header.Get("Authorization")
if bearer == "" {
return r.FormValue("access_token")
}
// pull/push git operations will require auth using
// Basic realm
if strings.HasPrefix(bearer, "Basic") {
_, tkn, ok := r.BasicAuth()
if !ok {
return ""
}
return tkn
}
bearer = strings.TrimPrefix(bearer, "Bearer ")
return bearer
}