webdav: parse and return sharepoint error response

fixes #3176

backend/webdav/odrvcookie/fetch.go

@@ -5,6 +5,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/xml"
+	"fmt"
 	"html/template"
 	"net/http"
 	"net/http/cookiejar"
@@ -32,13 +33,13 @@ type CookieResponse struct {
 	FedAuth http.Cookie
 }
 
-// SuccessResponse hold a response from the sharepoint webdav
-type SuccessResponse struct {
+// SharepointSuccessResponse holds a response from a successful microsoft login
+type SharepointSuccessResponse struct {
 	XMLName xml.Name            `xml:"Envelope"`
-	Succ    SuccessResponseBody `xml:"Body"`
+	Body    SuccessResponseBody `xml:"Body"`
 }
 
-// SuccessResponseBody is the body of a success response, it holds the token
+// SuccessResponseBody is the body of a successful response, it holds the token
 type SuccessResponseBody struct {
 	XMLName xml.Name
 	Type    string    `xml:"RequestSecurityTokenResponse>TokenType"`
@@ -47,6 +48,24 @@ type SuccessResponseBody struct {
 	Token   string    `xml:"RequestSecurityTokenResponse>RequestedSecurityToken>BinarySecurityToken"`
 }
 
+// SharepointError holds a error response microsoft login
+type SharepointError struct {
+	XMLName xml.Name          `xml:"Envelope"`
+	Body    ErrorResponseBody `xml:"Body"`
+}
+
+func (e *SharepointError) Error() string {
+	return fmt.Sprintf("%s: %s (%s)", e.Body.FaultCode, e.Body.Reason, e.Body.Detail)
+}
+
+// ErrorResponseBody contains the body of a erroneous repsonse
+type ErrorResponseBody struct {
+	XMLName   xml.Name
+	FaultCode string `xml:"Fault>Code>Subcode>Value"`
+	Reason    string `xml:"Fault>Reason>Text"`
+	Detail    string `xml:"Fault>Detail>error>internalerror>text"`
+}
+
 // reqString is a template that gets populated with the user data in order to retrieve a "BinarySecurityToken"
 const reqString = `<s:Envelope xmlns:s="http://www.w3.org/2003/05/soap-envelope"
 xmlns:a="http://www.w3.org/2005/08/addressing"
@@ -100,7 +119,7 @@ func (ca *CookieAuth) Cookies(ctx context.Context) (*CookieResponse, error) {
 	return ca.getSPCookie(tokenResp)
 }
 
-func (ca *CookieAuth) getSPCookie(conf *SuccessResponse) (*CookieResponse, error) {
+func (ca *CookieAuth) getSPCookie(conf *SharepointSuccessResponse) (*CookieResponse, error) {
 	spRoot, err := url.Parse(ca.endpoint)
 	if err != nil {
 		return nil, errors.Wrap(err, "Error while constructing endpoint URL")
@@ -123,7 +142,7 @@ func (ca *CookieAuth) getSPCookie(conf *SuccessResponse) (*CookieResponse, error
 	}
 
 	// Send the previously acquired Token as a Post parameter
-	if _, err = client.Post(u.String(), "text/xml", strings.NewReader(conf.Succ.Token)); err != nil {
+	if _, err = client.Post(u.String(), "text/xml", strings.NewReader(conf.Body.Token)); err != nil {
 		return nil, errors.Wrap(err, "Error while grabbing cookies from endpoint: %v")
 	}
 
@@ -141,7 +160,7 @@ func (ca *CookieAuth) getSPCookie(conf *SuccessResponse) (*CookieResponse, error
 	return &cookieResponse, nil
 }
 
-func (ca *CookieAuth) getSPToken(ctx context.Context) (conf *SuccessResponse, err error) {
+func (ca *CookieAuth) getSPToken(ctx context.Context) (conf *SharepointSuccessResponse, err error) {
 	reqData := map[string]interface{}{
 		"Username": ca.user,
 		"Password": ca.pass,
@@ -177,12 +196,21 @@ func (ca *CookieAuth) getSPToken(ctx context.Context) (conf *SuccessResponse, er
 	}
 	s := respBuf.Bytes()
 
-	conf = &SuccessResponse{}
+	conf = &SharepointSuccessResponse{}
 	err = xml.Unmarshal(s, conf)
+	if conf.Body.Token == "" {
+		// xml Unmarshal won't fail if the response doesn't contain a token
+		// However, the token will be empty
+		sErr := &SharepointError{}
+
+		errSErr := xml.Unmarshal(s, sErr)
+		if errSErr == nil {
+			return nil, sErr
+		}
+	}
+
 	if err != nil {
-		// FIXME: Try to parse with FailedResponse struct (check for server error code)
 		return nil, errors.Wrap(err, "Error while reading endpoint response")
 	}
-
 	return
 }