diff --git a/api/user.go b/api/user.go
index 68a4e6d56c..40bac7bd51 100644
--- a/api/user.go
+++ b/api/user.go
@@ -81,36 +81,7 @@ func createUser(c *Context, w http.ResponseWriter, r *http.Request) {
 
 	hash := r.URL.Query().Get("h")
 
-	shouldVerifyHash := true
-
-	if team.Type == model.TEAM_INVITE && len(team.AllowedDomains) > 0 && len(hash) == 0 {
-		domains := strings.Fields(strings.TrimSpace(strings.ToLower(strings.Replace(strings.Replace(team.AllowedDomains, "@", " ", -1), ",", " ", -1))))
-
-		matched := false
-		for _, d := range domains {
-			if strings.HasSuffix(user.Email, "@"+d) {
-				matched = true
-				break
-			}
-		}
-
-		if matched {
-			shouldVerifyHash = false
-		} else {
-			c.Err = model.NewAppError("createUser", "The signup link does not appear to be valid", "allowed domains failed")
-			return
-		}
-	}
-
-	if team.Type == model.TEAM_OPEN {
-		shouldVerifyHash = false
-	}
-
-	if len(hash) > 0 {
-		shouldVerifyHash = true
-	}
-
-	if shouldVerifyHash {
+	if IsVerifyHashRequired(user, team, hash) {
 		data := r.URL.Query().Get("d")
 		props := model.MapFromJson(strings.NewReader(data))
 
@@ -147,6 +118,38 @@ func createUser(c *Context, w http.ResponseWriter, r *http.Request) {
 
 }
 
+func IsVerifyHashRequired(user *model.User, team *model.Team, hash string) bool {
+	shouldVerifyHash := true
+
+	if team.Type == model.TEAM_INVITE && len(team.AllowedDomains) > 0 && len(hash) == 0 && user != nil {
+		domains := strings.Fields(strings.TrimSpace(strings.ToLower(strings.Replace(strings.Replace(team.AllowedDomains, "@", " ", -1), ",", " ", -1))))
+
+		matched := false
+		for _, d := range domains {
+			if strings.HasSuffix(user.Email, "@"+d) {
+				matched = true
+				break
+			}
+		}
+
+		if matched {
+			shouldVerifyHash = false
+		} else {
+			return true
+		}
+	}
+
+	if team.Type == model.TEAM_OPEN {
+		shouldVerifyHash = false
+	}
+
+	if len(hash) > 0 {
+		shouldVerifyHash = true
+	}
+
+	return shouldVerifyHash
+}
+
 func CreateValet(c *Context, team *model.Team) *model.User {
 	valet := &model.User{}
 	valet.TeamId = team.Id
@@ -1223,21 +1226,7 @@ func getStatuses(c *Context, w http.ResponseWriter, r *http.Request) {
 	}
 }
 
-func GetAuthorizationCode(c *Context, w http.ResponseWriter, r *http.Request, service, redirectUri string) {
-	params := mux.Vars(r)
-	teamName := params["team"]
-
-	if len(teamName) == 0 {
-		c.Err = model.NewAppError("GetAuthorizationCode", "Invalid team name", "team_name="+teamName)
-		c.Err.StatusCode = http.StatusBadRequest
-		return
-	}
-
-	// Make sure team exists
-	if result := <-Srv.Store.Team().GetByName(teamName); result.Err != nil {
-		c.Err = result.Err
-		return
-	}
+func GetAuthorizationCode(c *Context, w http.ResponseWriter, r *http.Request, teamName, service, redirectUri string) {
 
 	if s, ok := utils.Cfg.SSOSettings[service]; !ok || !s.Allow {
 		c.Err = model.NewAppError("GetAuthorizationCode", "Unsupported OAuth service provider", "service="+service)
diff --git a/web/react/components/signup_user_complete.jsx b/web/react/components/signup_user_complete.jsx
index 1b1fe15fb5..577651b901 100644
--- a/web/react/components/signup_user_complete.jsx
+++ b/web/react/components/signup_user_complete.jsx
@@ -119,7 +119,7 @@ module.exports = React.createClass({
                 <div className="form-group form-group--small">
                     <span></span>
                 </div>
-                <p>{"Choose your username and password for the " + this.props.teamDisplayName + " " + strings.Team} <a href={"/"+this.props.teamName+"/signup/gitlab"}>{"or sign up with GitLab."}</a></p>
+                <p>{"Choose your username and password for the " + this.props.teamDisplayName + " " + strings.Team} <a href={"/"+this.props.teamName+"/signup/gitlab"+window.location.search}>{"or sign up with GitLab."}</a></p>
                 <p>Your username can be made of lowercase letters and numbers.</p>
                 <label className="control-label">Username</label>
                 <div className={ name_error ? "form-group has-error" : "form-group" }>
diff --git a/web/web.go b/web/web.go
index ef2bae6242..975b650023 100644
--- a/web/web.go
+++ b/web/web.go
@@ -453,10 +453,48 @@ func resetPassword(c *api.Context, w http.ResponseWriter, r *http.Request) {
 func signupWithOAuth(c *api.Context, w http.ResponseWriter, r *http.Request) {
 	params := mux.Vars(r)
 	service := params["service"]
+	teamName := params["team"]
+
+	if len(teamName) == 0 {
+		c.Err = model.NewAppError("signupWithOAuth", "Invalid team name", "team_name="+teamName)
+		c.Err.StatusCode = http.StatusBadRequest
+		return
+	}
+
+	hash := r.URL.Query().Get("h")
+
+	var team *model.Team
+	if result := <-api.Srv.Store.Team().GetByName(teamName); result.Err != nil {
+		c.Err = result.Err
+		return
+	} else {
+		team = result.Data.(*model.Team)
+	}
+
+	if api.IsVerifyHashRequired(nil, team, hash) {
+		data := r.URL.Query().Get("d")
+		props := model.MapFromJson(strings.NewReader(data))
+
+		if !model.ComparePassword(hash, fmt.Sprintf("%v:%v", data, utils.Cfg.ServiceSettings.InviteSalt)) {
+			c.Err = model.NewAppError("createUser", "The signup link does not appear to be valid", "")
+			return
+		}
+
+		t, err := strconv.ParseInt(props["time"], 10, 64)
+		if err != nil || model.GetMillis()-t > 1000*60*60*48 { // 48 hours
+			c.Err = model.NewAppError("createUser", "The signup link has expired", "")
+			return
+		}
+
+		if team.Id != props["id"] {
+			c.Err = model.NewAppError("createUser", "Invalid team name", data)
+			return
+		}
+	}
 
 	redirectUri := c.GetSiteURL() + "/signup/" + service + "/complete"
 
-	api.GetAuthorizationCode(c, w, r, service, redirectUri)
+	api.GetAuthorizationCode(c, w, r, teamName, service, redirectUri)
 }
 
 func signupCompleteOAuth(c *api.Context, w http.ResponseWriter, r *http.Request) {
@@ -522,11 +560,23 @@ func signupCompleteOAuth(c *api.Context, w http.ResponseWriter, r *http.Request)
 func loginWithOAuth(c *api.Context, w http.ResponseWriter, r *http.Request) {
 	params := mux.Vars(r)
 	service := params["service"]
-	l4g.Debug(service)
+	teamName := params["team"]
+
+	if len(teamName) == 0 {
+		c.Err = model.NewAppError("loginWithOAuth", "Invalid team name", "team_name="+teamName)
+		c.Err.StatusCode = http.StatusBadRequest
+		return
+	}
+
+	// Make sure team exists
+	if result := <-api.Srv.Store.Team().GetByName(teamName); result.Err != nil {
+		c.Err = result.Err
+		return
+	}
 
 	redirectUri := c.GetSiteURL() + "/login/" + service + "/complete"
 
-	api.GetAuthorizationCode(c, w, r, service, redirectUri)
+	api.GetAuthorizationCode(c, w, r, teamName, service, redirectUri)
 }
 
 func loginCompleteOAuth(c *api.Context, w http.ResponseWriter, r *http.Request) {