Adding upstream version 0.28.1.

Signed-off-by: Daniel Baumann <daniel@debian.org>

tools/auth/apple.go

@@ -0,0 +1,166 @@
+package auth
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"strings"
+
+	"github.com/golang-jwt/jwt/v5"
+	"github.com/pocketbase/pocketbase/tools/types"
+	"github.com/spf13/cast"
+	"golang.org/x/oauth2"
+)
+
+func init() {
+	Providers[NameApple] = wrapFactory(NewAppleProvider)
+}
+
+var _ Provider = (*Apple)(nil)
+
+// NameApple is the unique name of the Apple provider.
+const NameApple string = "apple"
+
+// Apple allows authentication via Apple OAuth2.
+//
+// [OIDC differences]: https://bitbucket.org/openid/connect/src/master/How-Sign-in-with-Apple-differs-from-OpenID-Connect.md
+type Apple struct {
+	BaseProvider
+
+	jwksURL string
+}
+
+// NewAppleProvider creates a new Apple provider instance with some defaults.
+func NewAppleProvider() *Apple {
+	return &Apple{
+		BaseProvider: BaseProvider{
+			ctx:         context.Background(),
+			displayName: "Apple",
+			pkce:        true,
+			scopes:      []string{"name", "email"},
+			authURL:     "https://appleid.apple.com/auth/authorize",
+			tokenURL:    "https://appleid.apple.com/auth/token",
+		},
+		jwksURL: "https://appleid.apple.com/auth/keys",
+	}
+}
+
+// FetchAuthUser returns an AuthUser instance based on the provided token.
+//
+// API reference: https://developer.apple.com/documentation/sign_in_with_apple/tokenresponse.
+func (p *Apple) FetchAuthUser(token *oauth2.Token) (*AuthUser, error) {
+	data, err := p.FetchRawUserInfo(token)
+	if err != nil {
+		return nil, err
+	}
+
+	rawUser := map[string]any{}
+	if err := json.Unmarshal(data, &rawUser); err != nil {
+		return nil, err
+	}
+
+	extracted := struct {
+		Id            string `json:"sub"`
+		Name          string `json:"name"`
+		Email         string `json:"email"`
+		EmailVerified any    `json:"email_verified"` // could be string or bool
+		User          struct {
+			Name struct {
+				FirstName string `json:"firstName"`
+				LastName  string `json:"lastName"`
+			} `json:"name"`
+		} `json:"user"`
+	}{}
+	if err := json.Unmarshal(data, &extracted); err != nil {
+		return nil, err
+	}
+
+	user := &AuthUser{
+		Id:           extracted.Id,
+		Name:         extracted.Name,
+		RawUser:      rawUser,
+		AccessToken:  token.AccessToken,
+		RefreshToken: token.RefreshToken,
+	}
+
+	user.Expiry, _ = types.ParseDateTime(token.Expiry)
+
+	if cast.ToBool(extracted.EmailVerified) {
+		user.Email = extracted.Email
+	}
+
+	if user.Name == "" {
+		user.Name = strings.TrimSpace(extracted.User.Name.FirstName + " " + extracted.User.Name.LastName)
+	}
+
+	return user, nil
+}
+
+// FetchRawUserInfo implements Provider.FetchRawUserInfo interface.
+//
+// Apple doesn't have a UserInfo endpoint and claims about users
+// are instead included in the "id_token" (https://openid.net/specs/openid-connect-core-1_0.html#id_tokenExample)
+func (p *Apple) FetchRawUserInfo(token *oauth2.Token) ([]byte, error) {
+	idToken, _ := token.Extra("id_token").(string)
+
+	claims, err := p.parseAndVerifyIdToken(idToken)
+	if err != nil {
+		return nil, err
+	}
+
+	// Apple only returns the user object the first time the user authorizes the app
+	// https://developer.apple.com/documentation/sign_in_with_apple/sign_in_with_apple_js/configuring_your_webpage_for_sign_in_with_apple#3331292
+	rawUser, _ := token.Extra("user").(string)
+	if rawUser != "" {
+		user := map[string]any{}
+		err = json.Unmarshal([]byte(rawUser), &user)
+		if err != nil {
+			return nil, err
+		}
+		claims["user"] = user
+	}
+
+	return json.Marshal(claims)
+}
+
+func (p *Apple) parseAndVerifyIdToken(idToken string) (jwt.MapClaims, error) {
+	if idToken == "" {
+		return nil, errors.New("empty id_token")
+	}
+
+	// extract the token header params and claims
+	// ---
+	claims := jwt.MapClaims{}
+	t, _, err := jwt.NewParser().ParseUnverified(idToken, claims)
+	if err != nil {
+		return nil, err
+	}
+
+	// validate common claims per https://developer.apple.com/documentation/sign_in_with_apple/sign_in_with_apple_rest_api/verifying_a_user#3383769
+	// ---
+	jwtValidator := jwt.NewValidator(
+		jwt.WithExpirationRequired(),
+		jwt.WithIssuedAt(),
+		jwt.WithLeeway(idTokenLeeway),
+		jwt.WithIssuer("https://appleid.apple.com"),
+		jwt.WithAudience(p.clientId),
+	)
+	err = jwtValidator.Validate(claims)
+	if err != nil {
+		return nil, err
+	}
+
+	// validate id_token signature
+	//
+	// note: this step could be technically considered optional because we trust
+	// the token which is a result of direct TLS communication with the provider
+	// (see also https://openid.net/specs/openid-connect-core-1_0.html#IDTokenValidation)
+	// ---
+	kid, _ := t.Header["kid"].(string)
+	err = validateIdTokenSignature(p.ctx, idToken, p.jwksURL, kid)
+	if err != nil {
+		return nil, err
+	}
+
+	return claims, nil
+}