WebAuthn CredentialID field needs to be increased in size (#20530)

WebAuthn have updated their specification to set the maximum size of the
CredentialID to 1023 bytes. This is somewhat larger than our current
size and therefore we need to migrate.

The PR changes the struct to add CredentialIDBytes and migrates the CredentialID string 
to the bytes field before another migration drops the old CredentialID field. Another migration
renames this field back.

Fix #20457

Signed-off-by: Andrew Thornton <art27@cantab.net>

2 files changed, 9 insertions, 14 deletions

diff --git a/models/auth/webauthn.go b/models/auth/webauthn.go
index 2dc3043780..d3062342f5 100644
--- a/models/auth/webauthn.go
+++ b/models/auth/webauthn.go
@@ -6,7 +6,6 @@ package auth
 
 import (
 	"context"
-	"encoding/base32"
 	"fmt"
 	"strings"
 
@@ -20,14 +19,14 @@ import (
 // ErrWebAuthnCredentialNotExist represents a "ErrWebAuthnCRedentialNotExist" kind of error.
 type ErrWebAuthnCredentialNotExist struct {
 	ID           int64
-	CredentialID string
+	CredentialID []byte
 }
 
 func (err ErrWebAuthnCredentialNotExist) Error() string {
-	if err.CredentialID == "" {
+	if len(err.CredentialID) == 0 {
 		return fmt.Sprintf("WebAuthn credential does not exist [id: %d]", err.ID)
 	}
-	return fmt.Sprintf("WebAuthn credential does not exist [credential_id: %s]", err.CredentialID)
+	return fmt.Sprintf("WebAuthn credential does not exist [credential_id: %x]", err.CredentialID)
 }
 
 // IsErrWebAuthnCredentialNotExist checks if an error is a ErrWebAuthnCredentialNotExist.
@@ -43,7 +42,7 @@ type WebAuthnCredential struct {
 	Name            string
 	LowerName       string `xorm:"unique(s)"`
 	UserID          int64  `xorm:"INDEX unique(s)"`
-	CredentialID    string `xorm:"INDEX VARCHAR(410)"`
+	CredentialID    []byte `xorm:"INDEX VARBINARY(1024)"`
 	PublicKey       []byte
 	AttestationType string
 	AAGUID          []byte
@@ -94,9 +93,8 @@ type WebAuthnCredentialList []*WebAuthnCredential
 func (list WebAuthnCredentialList) ToCredentials() []webauthn.Credential {
 	creds := make([]webauthn.Credential, 0, len(list))
 	for _, cred := range list {
-		credID, _ := base32.HexEncoding.DecodeString(cred.CredentialID)
 		creds = append(creds, webauthn.Credential{
-			ID:              credID,
+			ID:              cred.CredentialID,
 			PublicKey:       cred.PublicKey,
 			AttestationType: cred.AttestationType,
 			Authenticator: webauthn.Authenticator{
@@ -164,11 +162,11 @@ func HasWebAuthnRegistrationsByUID(uid int64) (bool, error) {
 }
 
 // GetWebAuthnCredentialByCredID returns WebAuthn credential by credential ID
-func GetWebAuthnCredentialByCredID(userID int64, credID string) (*WebAuthnCredential, error) {
+func GetWebAuthnCredentialByCredID(userID int64, credID []byte) (*WebAuthnCredential, error) {
 	return getWebAuthnCredentialByCredID(db.DefaultContext, userID, credID)
 }
 
-func getWebAuthnCredentialByCredID(ctx context.Context, userID int64, credID string) (*WebAuthnCredential, error) {
+func getWebAuthnCredentialByCredID(ctx context.Context, userID int64, credID []byte) (*WebAuthnCredential, error) {
 	cred := new(WebAuthnCredential)
 	if found, err := db.GetEngine(ctx).Where("user_id = ? AND credential_id = ?", userID, credID).Get(cred); err != nil {
 		return nil, err
@@ -187,7 +185,7 @@ func createCredential(ctx context.Context, userID int64, name string, cred *weba
 	c := &WebAuthnCredential{
 		UserID:          userID,
 		Name:            name,
-		CredentialID:    base32.HexEncoding.EncodeToString(cred.ID),
+		CredentialID:    cred.ID,
 		PublicKey:       cred.PublicKey,
 		AttestationType: cred.AttestationType,
 		AAGUID:          cred.Authenticator.AAGUID,
diff --git a/models/auth/webauthn_test.go b/models/auth/webauthn_test.go
index 216bf11080..cc39691ce2 100644
--- a/models/auth/webauthn_test.go
+++ b/models/auth/webauthn_test.go
@@ -5,7 +5,6 @@
 package auth
 
 import (
-	"encoding/base32"
 	"testing"
 
 	"code.gitea.io/gitea/models/unittest"
@@ -61,9 +60,7 @@ func TestCreateCredential(t *testing.T) {
 	res, err := CreateCredential(1, "WebAuthn Created Credential", &webauthn.Credential{ID: []byte("Test")})
 	assert.NoError(t, err)
 	assert.Equal(t, "WebAuthn Created Credential", res.Name)
-	bs, err := base32.HexEncoding.DecodeString(res.CredentialID)
-	assert.NoError(t, err)
-	assert.Equal(t, []byte("Test"), bs)
+	assert.Equal(t, []byte("Test"), res.CredentialID)
 
 	unittest.AssertExistsIf(t, true, &WebAuthnCredential{Name: "WebAuthn Created Credential", UserID: 1})
 }