Commit 741f338b authored by Ondrej Holy's avatar Ondrej Holy

user-accounts: Check username validity over usermod

Username policies differ across the distributions. See the discussion on:
!359

It is not possible to hard-code some rules here without the need for
downstream modifications. Let's check the validity of usernames dynamically
over "usermod" to prevent this.

Just be careful that this is based on undocumented usermod behavior, which
may change in the future.
parent ed22dd28
Pipeline #57098 passed with stages
in 7 minutes and 9 seconds
......@@ -94,6 +94,7 @@ struct _CcAddUserDialog {
gint local_username_timeout_id;
ActUserPasswordMode local_password_mode;
gint local_password_timeout_id;
gboolean local_valid_username;
guint realmd_watch;
CcRealmManager *realm_manager;
......@@ -277,22 +278,14 @@ update_password_strength (CcAddUserDialog *self)
static gboolean
local_validate (CcAddUserDialog *self)
{
gboolean valid_login;
gboolean valid_name;
gboolean valid_password;
const gchar *name;
const gchar *password;
const gchar *verify;
gchar *tip;
gint strength;
name = gtk_combo_box_text_get_active_text (self->local_username_combo);
valid_login = is_valid_username (name, &tip);
gtk_label_set_label (self->local_username_hint_label, tip);
g_free (tip);
if (valid_login) {
if (self->local_valid_username) {
set_entry_validation_checkmark (self->local_username_entry);
}
......@@ -311,15 +304,45 @@ local_validate (CcAddUserDialog *self)
valid_password = TRUE;
}
return valid_name && valid_login && valid_password;
return valid_name && self->local_valid_username && valid_password;
}
static void local_username_is_valid_cb (GObject *source_object,
GAsyncResult *result,
gpointer user_data)
{
CcAddUserDialog *self = CC_ADD_USER_DIALOG (user_data);
g_autoptr(GError) error = NULL;
g_autofree gchar *tip = NULL;
g_autofree gchar *name = NULL;
g_autofree gchar *username = NULL;
gboolean valid;
valid = is_valid_username_finish (result, &tip, &username, &error);
if (error != NULL) {
g_warning ("Could not check username by usermod: %s", error->message);
valid = TRUE;
}
name = gtk_combo_box_text_get_active_text (self->local_username_combo);
if (g_strcmp0 (name, username) == 0) {
self->local_valid_username = valid;
gtk_label_set_label (self->local_username_hint_label, tip);
dialog_validate (self);
}
g_object_unref (self);
}
static gboolean
local_username_timeout (CcAddUserDialog *self)
{
g_autofree gchar *name = NULL;
self->local_username_timeout_id = 0;
dialog_validate (self);
name = gtk_combo_box_text_get_active_text (self->local_username_combo);
is_valid_username_async (name, NULL, local_username_is_valid_cb, g_object_ref (self));
return FALSE;
}
......@@ -357,6 +380,7 @@ local_username_combo_changed_cb (CcAddUserDialog *self)
clear_entry_validation_error (self->local_username_entry);
gtk_widget_set_sensitive (GTK_WIDGET (self->add_button), FALSE);
self->local_valid_username = FALSE;
self->local_username_timeout_id = g_timeout_add (PASSWORD_CHECK_TIMEOUT, (GSourceFunc) local_username_timeout, self);
}
......
......@@ -389,61 +389,147 @@ is_valid_name (const gchar *name)
return !is_empty;
}
gboolean
is_valid_username (const gchar *username, gchar **tip)
typedef struct {
gchar *username;
gchar *tip;
} isValidUsernameData;
static void
is_valid_username_data_free (isValidUsernameData *data)
{
gboolean empty;
gboolean in_use;
gboolean too_long;
gboolean valid;
const gchar *c;
g_free (data->username);
g_free (data->tip);
g_free (data);
}
/* Taken from usermod.c in shadow-utils. */
#define E_SUCCESS 0
#define E_BAD_ARG 3
#define E_NOTFOUND 6
static void
is_valid_username_child_watch_cb (GPid pid,
gint status,
gpointer user_data)
{
GTask *task = G_TASK (user_data);
isValidUsernameData *data = g_task_get_task_data (task);
GError *error = NULL;
gboolean valid = FALSE;
const gchar *tip = NULL;
if (WIFEXITED (status)) {
switch (WEXITSTATUS (status)) {
case E_NOTFOUND:
valid = TRUE;
break;
case E_BAD_ARG:
tip = _("The username should usually only consist of lower case letters from a-z, digits and the following characters: - _");
valid = FALSE;
break;
case E_SUCCESS:
tip = _("Sorry, that user name isn’t available. Please try another.");
valid = FALSE;
break;
}
}
if (valid || tip != NULL) {
data->tip = g_strdup (tip);
g_task_return_boolean (task, valid);
}
else {
g_spawn_check_exit_status (status, &error);
g_task_return_error (task, error);
}
g_spawn_close_pid (pid);
g_object_unref (task);
}
void
is_valid_username_async (const gchar *username,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer callback_data)
{
GTask *task;
isValidUsernameData *data;
gchar *argv[6];
GPid pid;
GError *error;
task = g_task_new (NULL, cancellable, callback, callback_data);
g_task_set_source_tag (task, is_valid_username_async);
data = g_new0 (isValidUsernameData, 1);
data->username = g_strdup (username);
g_task_set_task_data (task, data, (GDestroyNotify) is_valid_username_data_free);
if (username == NULL || username[0] == '\0') {
empty = TRUE;
in_use = FALSE;
too_long = FALSE;
} else {
empty = FALSE;
in_use = is_username_used (username);
too_long = strlen (username) > get_username_max_length ();
g_task_return_boolean (task, FALSE);
g_object_unref (task);
return;
}
valid = TRUE;
if (!in_use && !empty && !too_long) {
/* First char must be a letter, and it must only composed
* of ASCII letters, digits, and a '.', '-', '_'
*/
for (c = username; *c; c++) {
if (! ((*c >= 'a' && *c <= 'z') ||
(*c >= 'A' && *c <= 'Z') ||
(*c >= '0' && *c <= '9') ||
(*c == '_') || (*c == '.') ||
(*c == '-' && c != username)))
valid = FALSE;
}
else if (strlen (username) > get_username_max_length ()) {
data->tip = g_strdup (_("The username is too long."));
g_task_return_boolean (task, FALSE);
g_object_unref (task);
return;
}
valid = !empty && !in_use && !too_long && valid;
/* "usermod --login" is meant to be used to change a username, but the
* exit codes can be safely abused to check the validity of username.
* However, the current "usermod" implementation may change in the
* future, so it would be nice to have some official way for this
* instead of relying on the current "--login" implementation.
*/
argv[0] = "usermod";
argv[1] = "--login";
argv[2] = data->username;
argv[3] = "--";
argv[4] = data->username;
argv[5] = NULL;
if (!g_spawn_async (NULL, argv, NULL,
G_SPAWN_SEARCH_PATH | G_SPAWN_DO_NOT_REAP_CHILD |
G_SPAWN_STDOUT_TO_DEV_NULL | G_SPAWN_STDERR_TO_DEV_NULL,
NULL, NULL, &pid, &error)) {
g_task_return_error (task, error);
g_object_unref (task);
if (!empty && (in_use || too_long || !valid)) {
if (in_use) {
*tip = g_strdup (_("Sorry, that user name isn’t available. Please try another."));
}
else if (too_long) {
*tip = g_strdup_printf (_("The username is too long."));
}
else if (username[0] == '-') {
*tip = g_strdup (_("The username cannot start with a “-”."));
}
else {
*tip = g_strdup (_("The username should only consist of upper and lower case letters from a-z, digits and the following characters: . - _"));
}
return;
}
else {
*tip = g_strdup (_("This will be used to name your home folder and can’t be changed."));
g_child_watch_add (pid, (GChildWatchFunc) is_valid_username_child_watch_cb, task);
}
gboolean
is_valid_username_finish (GAsyncResult *result,
gchar **tip,
gchar **username,
GError **error)
{
GTask *task;
isValidUsernameData *data;
g_return_val_if_fail (g_task_is_valid (result, NULL), FALSE);
task = G_TASK (result);
data = g_task_get_task_data (task);
if (tip != NULL) {
*tip = g_steal_pointer (&data->tip);
if (*tip == NULL)
*tip = g_strdup (_("This will be used to name your home folder and can’t be changed."));
}
return valid;
if (username != NULL)
*username = g_steal_pointer (&data->username);
return g_task_propagate_boolean (task, error);
}
GdkPixbuf *
......
......@@ -41,8 +41,15 @@ void clear_entry_validation_error (GtkEntry *entry);
gsize get_username_max_length (void);
gboolean is_username_used (const gchar *username);
gboolean is_valid_name (const gchar *name);
gboolean is_valid_username (const gchar *name,
gchar **tip);
void is_valid_username_async (const gchar *username,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer callback_data);
gboolean is_valid_username_finish (GAsyncResult *result,
gchar **tip,
gchar **username,
GError **error);
GdkPixbuf *round_image (GdkPixbuf *pixbuf,
gint icon_size);
void generate_user_avatar (ActUser *user);
......
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