[MM-57942] Fix a panic on password is too long (#27449)

* return error from bcrypt, handle gracefully; remove dead code

* linting

* linting

* i18n

* fix test

* fill out translations

server/public/model/user.go

@@ -14,6 +14,8 @@ import (
 	"time"
 	"unicode/utf8"
 
+	"github.com/pkg/errors"
+
 	"golang.org/x/crypto/bcrypt"
 	"golang.org/x/text/language"
 
@@ -378,10 +380,6 @@ func (u *User) IsValid() *AppError {
 		return InvalidUserError("auth_data_pwd", u.Id, *u.AuthData)
 	}
 
-	if len(u.Password) > UserPasswordMaxLength {
-		return InvalidUserError("password_limit", u.Id, "")
-	}
-
 	if !IsValidLocale(u.Locale) {
 		return InvalidUserError("locale", u.Id, u.Locale)
 	}
@@ -430,7 +428,7 @@ func NormalizeEmail(email string) string {
 // PreSave will set the Id and Username if missing.  It will also fill
 // in the CreateAt, UpdateAt times.  It will also hash the password.  It should
 // be run before saving the user to the db.
-func (u *User) PreSave() {
+func (u *User) PreSave() *AppError {
 	if u.Id == "" {
 		u.Id = NewId()
 	}
@@ -477,7 +475,15 @@ func (u *User) PreSave() {
 	}
 
 	if u.Password != "" {
-		u.Password = HashPassword(u.Password)
+		hashed, err := HashPassword(u.Password)
+		if errors.Is(err, bcrypt.ErrPasswordTooLong) {
+			return NewAppError("User.PreSave", "model.user.pre_save.password_too_long.app_error",
+				nil, "user_id="+u.Id, http.StatusBadRequest).Wrap(err)
+		} else if err != nil {
+			return NewAppError("User.PreSave", "model.user.pre_save.password_hash.app_error",
+				nil, "user_id="+u.Id, http.StatusBadRequest).Wrap(err)
+		}
+		u.Password = hashed
 	}
 
 	cs := u.GetCustomStatus()
@@ -485,6 +491,8 @@ func (u *User) PreSave() {
 		cs.PreSave()
 		u.SetCustomStatus(cs)
 	}
+
+	return nil
 }
 
 // PreUpdate should be run before updating the user in the db.
@@ -928,13 +936,13 @@ func (u *UserPatch) SetField(fieldName string, fieldValue string) {
 }
 
 // HashPassword generates a hash using the bcrypt.GenerateFromPassword
-func HashPassword(password string) string {
+func HashPassword(password string) (string, error) {
 	hash, err := bcrypt.GenerateFromPassword([]byte(password), 10)
 	if err != nil {
-		panic(err)
+		return "", err
 	}
 
-	return string(hash)
+	return string(hash), nil
 }
 
 var validUsernameChars = regexp.MustCompile(`^[a-z0-9\.\-_]+$`)

server/public/model/user_test.go

@@ -9,6 +9,8 @@ import (
 	"strings"
 	"testing"
 
+	"golang.org/x/crypto/bcrypt"
+
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
@@ -47,12 +49,19 @@ func TestUserDeepCopy(t *testing.T) {
 
 func TestUserPreSave(t *testing.T) {
 	user := User{Password: "test"}
-	user.PreSave()
+	err := user.PreSave()
+	require.Nil(t, err)
 	user.Etag(true, true)
 	assert.NotNil(t, user.Timezone, "Timezone is nil")
 	assert.Equal(t, user.Timezone["useAutomaticTimezone"], "true", "Timezone is not set to default")
 }
 
+func TestUserPreSavePwdTooLong(t *testing.T) {
+	user := User{Password: strings.Repeat("1234567890", 8)}
+	err := user.PreSave()
+	assert.ErrorIs(t, err, bcrypt.ErrPasswordTooLong)
+}
+
 func TestUserPreUpdate(t *testing.T) {
 	user := User{Password: "test"}
 	user.PreUpdate()