drone/internal/auth/authn/token.go
2023-09-07 00:58:23 +00:00

124 lines
3.3 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/api/request"
"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, sourceRouter SourceRouter) (*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 {
// Check query param first (as that's most immediately visible to caller)
if queryToken, ok := request.GetAccessTokenFromQuery(r); ok {
return queryToken
}
// check authorization header next
headerToken := r.Header.Get(request.HeaderAuthorization)
switch {
// in case of git push / pull it would be basic auth and token is in password
case strings.HasPrefix(headerToken, "Basic "):
// return pwd either way - if it's invalid pwd is empty string which we'd return anyway
_, pwd, _ := r.BasicAuth()
return pwd
// strip bearer prefix if present
case strings.HasPrefix(headerToken, "Bearer "):
return headerToken[7:]
// otherwise use value as is
case headerToken != "":
return headerToken
}
// check cookies last (as that's least visible to caller)
if cookieToken, ok := request.GetTokenFromCookie(r); ok {
return cookieToken
}
// no token found
return ""
}