1 files changed, 142 insertions, 0 deletions
diff --git a/modules/auth/sso/oauth2.go b/modules/auth/sso/oauth2.go
new file mode 100644
index 0000000000..e677490b80
--- /dev/null
+++ b/modules/auth/sso/oauth2.go
@@ -0,0 +1,142 @@
+// Copyright 2014 The Gogs Authors. All rights reserved.
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package sso
+
+import (
+	"strings"
+	"time"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/timeutil"
+
+	"gitea.com/macaron/macaron"
+	"gitea.com/macaron/session"
+)
+
+// Ensure the struct implements the interface.
+var (
+	_ SingleSignOn = &OAuth2{}
+)
+
+// CheckOAuthAccessToken returns uid of user from oauth token
+func CheckOAuthAccessToken(accessToken string) int64 {
+	// JWT tokens require a "."
+	if !strings.Contains(accessToken, ".") {
+		return 0
+	}
+	token, err := models.ParseOAuth2Token(accessToken)
+	if err != nil {
+		log.Trace("ParseOAuth2Token: %v", err)
+		return 0
+	}
+	var grant *models.OAuth2Grant
+	if grant, err = models.GetOAuth2GrantByID(token.GrantID); err != nil || grant == nil {
+		return 0
+	}
+	if token.Type != models.TypeAccessToken {
+		return 0
+	}
+	if token.ExpiresAt < time.Now().Unix() || token.IssuedAt > time.Now().Unix() {
+		return 0
+	}
+	return grant.UserID
+}
+
+// OAuth2 implements the SingleSignOn interface and authenticates requests
+// (API requests only) by looking for an OAuth token in query parameters or the
+// "Authorization" header.
+type OAuth2 struct {
+}
+
+// Init does nothing as the OAuth2 implementation does not need to allocate any resources
+func (o *OAuth2) Init() error {
+	return nil
+}
+
+// Free does nothing as the OAuth2 implementation does not have to release any resources
+func (o *OAuth2) Free() error {
+	return nil
+}
+
+// userIDFromToken returns the user id corresponding to the OAuth token.
+func (o *OAuth2) userIDFromToken(ctx *macaron.Context) int64 {
+	// Check access token.
+	tokenSHA := ctx.Query("token")
+	if len(tokenSHA) == 0 {
+		tokenSHA = ctx.Query("access_token")
+	}
+	if len(tokenSHA) == 0 {
+		// Well, check with header again.
+		auHead := ctx.Req.Header.Get("Authorization")
+		if len(auHead) > 0 {
+			auths := strings.Fields(auHead)
+			if len(auths) == 2 && (auths[0] == "token" || strings.ToLower(auths[0]) == "bearer") {
+				tokenSHA = auths[1]
+			}
+		}
+	}
+	if len(tokenSHA) == 0 {
+		return 0
+	}
+
+	// Let's see if token is valid.
+	if strings.Contains(tokenSHA, ".") {
+		uid := CheckOAuthAccessToken(tokenSHA)
+		if uid != 0 {
+			ctx.Data["IsApiToken"] = true
+		}
+		return uid
+	}
+	t, err := models.GetAccessTokenBySHA(tokenSHA)
+	if err != nil {
+		if models.IsErrAccessTokenNotExist(err) || models.IsErrAccessTokenEmpty(err) {
+			log.Error("GetAccessTokenBySHA: %v", err)
+		}
+		return 0
+	}
+	t.UpdatedUnix = timeutil.TimeStampNow()
+	if err = models.UpdateAccessToken(t); err != nil {
+		log.Error("UpdateAccessToken: %v", err)
+	}
+	ctx.Data["IsApiToken"] = true
+	return t.UID
+}
+
+// IsEnabled returns true as this plugin is enabled by default and its not possible
+// to disable it from settings.
+func (o *OAuth2) IsEnabled() bool {
+	return true
+}
+
+// VerifyAuthData extracts the user ID from the OAuth token in the query parameters
+// or the "Authorization" header and returns the corresponding user object for that ID.
+// If verification is successful returns an existing user object.
+// Returns nil if verification fails.
+func (o *OAuth2) VerifyAuthData(ctx *macaron.Context, sess session.Store) *models.User {
+	if !models.HasEngine {
+		return nil
+	}
+
+	if !isAPIPath(ctx) && !isAttachmentDownload(ctx) {
+		return nil
+	}
+
+	id := o.userIDFromToken(ctx)
+	if id <= 0 {
+		return nil
+	}
+
+	user, err := models.GetUserByID(id)
+	if err != nil {
+		if !models.IsErrUserNotExist(err) {
+			log.Error("GetUserByName: %v", err)
+		}
+		return nil
+	}
+
+	return user
+}