gnome-control-center/panels/user-accounts/user-utils.c
Ondrej Holy 1f71ae6046 user-accounts: Check username validity over usermod
Username policies differ across the distributions. See the discussion on:
https://gitlab.gnome.org/GNOME/gnome-control-center/merge_requests/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.
2019-08-26 16:26:45 +03:00

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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*-
*
* Copyright 2009-2010 Red Hat, Inc,
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*
* Written by: Matthias Clasen <mclasen@redhat.com>
*/
#include "config.h"
#include <math.h>
#include <stdlib.h>
#include <sys/types.h>
#include <limits.h>
#include <unistd.h>
#include <utmpx.h>
#include <pwd.h>
#include <gio/gio.h>
#include <gio/gunixoutputstream.h>
#include <glib/gi18n.h>
#include <glib/gstdio.h>
#include "user-utils.h"
#define IMAGE_SIZE 512
typedef struct {
gchar *text;
gchar *placeholder_str;
GIcon *icon;
gunichar placeholder;
gulong query_id;
} IconShapeData;
static IconShapeData *
icon_shape_data_new (const gchar *text,
const gchar *placeholder,
GIcon *icon)
{
IconShapeData *data;
data = g_new0 (IconShapeData, 1);
data->text = g_strdup (text);
data->placeholder_str = g_strdup (placeholder);
data->placeholder = g_utf8_get_char_validated (placeholder, -1);
data->icon = g_object_ref (icon);
return data;
}
static void
icon_shape_data_free (gpointer user_data)
{
IconShapeData *data = user_data;
g_free (data->text);
g_free (data->placeholder_str);
g_object_unref (data->icon);
g_free (data);
}
static void
icon_shape_renderer (cairo_t *cr,
PangoAttrShape *attr,
gboolean do_path,
gpointer user_data)
{
IconShapeData *data = user_data;
gdouble x, y;
cairo_get_current_point (cr, &x, &y);
if (GPOINTER_TO_UINT (attr->data) == data->placeholder) {
gdouble ascent;
gdouble height;
GdkPixbuf *pixbuf;
GtkIconInfo *info;
ascent = pango_units_to_double (attr->ink_rect.y);
height = pango_units_to_double (attr->ink_rect.height);
info = gtk_icon_theme_lookup_by_gicon (gtk_icon_theme_get_default (),
data->icon,
(gint)height,
GTK_ICON_LOOKUP_FORCE_SIZE | GTK_ICON_LOOKUP_USE_BUILTIN);
pixbuf = gtk_icon_info_load_icon (info, NULL);
g_object_unref (info);
cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
cairo_reset_clip (cr);
gdk_cairo_set_source_pixbuf (cr, pixbuf, x, y + ascent);
cairo_paint (cr);
g_object_unref (pixbuf);
}
}
static PangoAttrList *
create_shape_attr_list_for_layout (PangoLayout *layout,
IconShapeData *data)
{
PangoAttrList *attrs;
PangoFontMetrics *metrics;
gint ascent, descent;
PangoRectangle ink_rect, logical_rect;
const gchar *p;
const gchar *text;
gint placeholder_len;
/* Get font metrics and prepare fancy shape size */
metrics = pango_context_get_metrics (pango_layout_get_context (layout),
pango_layout_get_font_description (layout),
NULL);
ascent = pango_font_metrics_get_ascent (metrics);
descent = pango_font_metrics_get_descent (metrics);
pango_font_metrics_unref (metrics);
logical_rect.x = 0;
logical_rect.y = - ascent;
logical_rect.width = ascent + descent;
logical_rect.height = ascent + descent;
ink_rect = logical_rect;
attrs = pango_attr_list_new ();
text = pango_layout_get_text (layout);
placeholder_len = strlen (data->placeholder_str);
for (p = text; (p = strstr (p, data->placeholder_str)); p += placeholder_len) {
PangoAttribute *attr;
attr = pango_attr_shape_new_with_data (&ink_rect,
&logical_rect,
GUINT_TO_POINTER (g_utf8_get_char (p)),
NULL, NULL);
attr->start_index = p - text;
attr->end_index = attr->start_index + placeholder_len;
pango_attr_list_insert (attrs, attr);
}
return attrs;
}
static gboolean
query_unlock_tooltip (GtkWidget *widget,
gint x,
gint y,
gboolean keyboard_tooltip,
GtkTooltip *tooltip,
gpointer user_data)
{
GtkWidget *label;
PangoLayout *layout;
PangoAttrList *attrs;
IconShapeData *data;
data = g_object_get_data (G_OBJECT (widget), "icon-shape-data");
label = g_object_get_data (G_OBJECT (widget), "tooltip-label");
if (label == NULL) {
label = gtk_label_new (data->text);
g_object_ref_sink (label);
g_object_set_data_full (G_OBJECT (widget),
"tooltip-label", label, g_object_unref);
}
layout = gtk_label_get_layout (GTK_LABEL (label));
pango_cairo_context_set_shape_renderer (pango_layout_get_context (layout),
icon_shape_renderer,
data, NULL);
attrs = create_shape_attr_list_for_layout (layout, data);
gtk_label_set_attributes (GTK_LABEL (label), attrs);
pango_attr_list_unref (attrs);
gtk_tooltip_set_custom (tooltip, label);
return TRUE;
}
void
setup_tooltip_with_embedded_icon (GtkWidget *widget,
const gchar *text,
const gchar *placeholder,
GIcon *icon)
{
IconShapeData *data;
data = g_object_get_data (G_OBJECT (widget), "icon-shape-data");
if (data) {
gtk_widget_set_has_tooltip (widget, FALSE);
g_signal_handler_disconnect (widget, data->query_id);
g_object_set_data (G_OBJECT (widget), "icon-shape-data", NULL);
g_object_set_data (G_OBJECT (widget), "tooltip-label", NULL);
}
if (!placeholder) {
gtk_widget_set_tooltip_text (widget, text);
return;
}
data = icon_shape_data_new (text, placeholder, icon);
g_object_set_data_full (G_OBJECT (widget),
"icon-shape-data",
data,
icon_shape_data_free);
gtk_widget_set_has_tooltip (widget, TRUE);
data->query_id = g_signal_connect (widget, "query-tooltip",
G_CALLBACK (query_unlock_tooltip), NULL);
}
gboolean
show_tooltip_now (GtkWidget *widget,
GdkEvent *event)
{
GtkSettings *settings;
gint timeout;
settings = gtk_widget_get_settings (widget);
g_object_get (settings, "gtk-tooltip-timeout", &timeout, NULL);
g_object_set (settings, "gtk-tooltip-timeout", 1, NULL);
gtk_tooltip_trigger_tooltip_query (gtk_widget_get_display (widget));
g_object_set (settings, "gtk-tooltip-timeout", timeout, NULL);
return FALSE;
}
static gboolean
query_tooltip (GtkWidget *widget,
gint x,
gint y,
gboolean keyboard_mode,
GtkTooltip *tooltip,
gpointer user_data)
{
gchar *tip;
if (GTK_ENTRY_ICON_SECONDARY == gtk_entry_get_icon_at_pos (GTK_ENTRY (widget), x, y)) {
tip = gtk_entry_get_icon_tooltip_text (GTK_ENTRY (widget),
GTK_ENTRY_ICON_SECONDARY);
gtk_tooltip_set_text (tooltip, tip);
g_free (tip);
return TRUE;
}
else {
return FALSE;
}
}
static void
icon_released (GtkEntry *entry,
GtkEntryIconPosition pos,
GdkEvent *event,
gpointer user_data)
{
GtkSettings *settings;
gint timeout;
settings = gtk_widget_get_settings (GTK_WIDGET (entry));
g_object_get (settings, "gtk-tooltip-timeout", &timeout, NULL);
g_object_set (settings, "gtk-tooltip-timeout", 1, NULL);
gtk_tooltip_trigger_tooltip_query (gtk_widget_get_display (GTK_WIDGET (entry)));
g_object_set (settings, "gtk-tooltip-timeout", timeout, NULL);
}
void
set_entry_validation_error (GtkEntry *entry,
const gchar *text)
{
g_object_set (entry, "caps-lock-warning", FALSE, NULL);
gtk_entry_set_icon_from_icon_name (entry,
GTK_ENTRY_ICON_SECONDARY,
"dialog-warning-symbolic");
gtk_entry_set_icon_activatable (entry,
GTK_ENTRY_ICON_SECONDARY,
TRUE);
g_signal_connect (entry, "icon-release",
G_CALLBACK (icon_released), FALSE);
g_signal_connect (entry, "query-tooltip",
G_CALLBACK (query_tooltip), NULL);
g_object_set (entry, "has-tooltip", TRUE, NULL);
gtk_entry_set_icon_tooltip_text (entry,
GTK_ENTRY_ICON_SECONDARY,
text);
}
void
set_entry_generation_icon (GtkEntry *entry)
{
g_object_set (entry, "caps-lock-warning", FALSE, NULL);
gtk_entry_set_icon_from_icon_name (entry, GTK_ENTRY_ICON_SECONDARY, "system-run-symbolic");
gtk_entry_set_icon_activatable (entry, GTK_ENTRY_ICON_SECONDARY, TRUE);
}
void
set_entry_validation_checkmark (GtkEntry *entry)
{
g_object_set (entry, "caps-lock-warning", FALSE, NULL);
gtk_entry_set_icon_from_icon_name (entry, GTK_ENTRY_ICON_SECONDARY, "object-select-symbolic");
gtk_entry_set_icon_activatable (entry, GTK_ENTRY_ICON_SECONDARY, FALSE);
}
void
clear_entry_validation_error (GtkEntry *entry)
{
gboolean warning;
g_object_get (entry, "caps-lock-warning", &warning, NULL);
if (warning)
return;
g_object_set (entry, "has-tooltip", FALSE, NULL);
gtk_entry_set_icon_from_pixbuf (entry,
GTK_ENTRY_ICON_SECONDARY,
NULL);
g_object_set (entry, "caps-lock-warning", TRUE, NULL);
}
/* Taken from defines.h in shadow-utils. On Linux, this value is much smaller
* than the sysconf limit LOGIN_NAME_MAX, and values larger than this will
* result in failure when running useradd. We could check UT_NAMESIZE instead,
* but that is nonstandard. Better to use POSIX utmpx.
*/
gsize
get_username_max_length (void)
{
return sizeof (((struct utmpx *)NULL)->ut_user);
}
gboolean
is_username_used (const gchar *username)
{
struct passwd *pwent;
if (username == NULL || username[0] == '\0') {
return FALSE;
}
pwent = getpwnam (username);
return pwent != NULL;
}
gboolean
is_valid_name (const gchar *name)
{
gboolean is_empty = TRUE;
const gchar *c;
/* Valid names must contain:
* 1) at least one character.
* 2) at least one non-"space" character.
*/
for (c = name; *c; c++) {
gunichar unichar;
unichar = g_utf8_get_char_validated (c, -1);
/* Partial UTF-8 sequence or end of string */
if (unichar == (gunichar) -1 || unichar == (gunichar) -2)
break;
/* Check for non-space character */
if (!g_unichar_isspace (unichar)) {
is_empty = FALSE;
break;
}
}
return !is_empty;
}
typedef struct {
gchar *username;
gchar *tip;
} isValidUsernameData;
static void
is_valid_username_data_free (isValidUsernameData *data)
{
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 isnt 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') {
g_task_return_boolean (task, FALSE);
g_object_unref (task);
return;
}
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;
}
/* "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);
return;
}
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 cant be changed."));
}
if (username != NULL)
*username = g_steal_pointer (&data->username);
return g_task_propagate_boolean (task, error);
}
GdkPixbuf *
round_image (GdkPixbuf *pixbuf)
{
GdkPixbuf *dest = NULL;
cairo_surface_t *surface;
cairo_t *cr;
gint size;
size = gdk_pixbuf_get_width (pixbuf);
surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, size, size);
cr = cairo_create (surface);
/* Clip a circle */
cairo_arc (cr, size/2, size/2, size/2, 0, 2 * G_PI);
cairo_clip (cr);
cairo_new_path (cr);
gdk_cairo_set_source_pixbuf (cr, pixbuf, 0, 0);
cairo_paint (cr);
dest = gdk_pixbuf_get_from_surface (surface, 0, 0, size, size);
cairo_surface_destroy (surface);
cairo_destroy (cr);
return dest;
}
static gchar *
extract_initials_from_name (const gchar *name)
{
GString *initials;
g_autofree gchar *p = NULL;
g_autofree gchar *normalized = NULL;
gunichar unichar;
gpointer q = NULL;
p = g_utf8_strup (name, -1);
normalized = g_utf8_normalize (g_strstrip (p), -1, G_NORMALIZE_DEFAULT_COMPOSE);
if (normalized == NULL) {
return NULL;
}
initials = g_string_new ("");
unichar = g_utf8_get_char (normalized);
g_string_append_unichar (initials, unichar);
q = g_utf8_strrchr (normalized, -1, ' ');
if (q != NULL && g_utf8_next_char (q) != NULL) {
q = g_utf8_next_char (q);
unichar = g_utf8_get_char (q);
g_string_append_unichar (initials, unichar);
}
return g_string_free (initials, FALSE);
}
static GdkRGBA
get_color_for_name (const gchar *name)
{
// https://gitlab.gnome.org/Community/Design/HIG-app-icons/blob/master/GNOME%20HIG.gpl
static gdouble gnome_color_palette[][3] = {
{ 98, 160, 234 },
{ 53, 132, 228 },
{ 28, 113, 216 },
{ 26, 95, 180 },
{ 87, 227, 137 },
{ 51, 209, 122 },
{ 46, 194, 126 },
{ 38, 162, 105 },
{ 248, 228, 92 },
{ 246, 211, 45 },
{ 245, 194, 17 },
{ 229, 165, 10 },
{ 255, 163, 72 },
{ 255, 120, 0 },
{ 230, 97, 0 },
{ 198, 70, 0 },
{ 237, 51, 59 },
{ 224, 27, 36 },
{ 192, 28, 40 },
{ 165, 29, 45 },
{ 192, 97, 203 },
{ 163, 71, 186 },
{ 129, 61, 156 },
{ 97, 53, 131 },
{ 181, 131, 90 },
{ 152, 106, 68 },
{ 134, 94, 60 },
{ 99, 69, 44 }
};
GdkRGBA color = { 255, 255, 255, 1.0 };
guint hash;
gint number_of_colors;
gint idx;
if (name == NULL || strlen (name) == 0)
return color;
hash = g_str_hash (name);
number_of_colors = G_N_ELEMENTS (gnome_color_palette);
idx = hash % number_of_colors;
color.red = gnome_color_palette[idx][0];
color.green = gnome_color_palette[idx][1];
color.blue = gnome_color_palette[idx][2];
return color;
}
static cairo_surface_t *
generate_user_picture (const gchar *name, gint size)
{
PangoFontDescription *font_desc;
g_autofree gchar *initials = extract_initials_from_name (name);
g_autofree gchar *font = g_strdup_printf ("Sans %d", (int)ceil (size / 2.5));
PangoLayout *layout;
GdkRGBA color = get_color_for_name (name);
cairo_surface_t *surface;
gint width, height;
cairo_t *cr;
surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
size,
size);
cr = cairo_create (surface);
cairo_rectangle (cr, 0, 0, size, size);
cairo_set_source_rgb (cr, color.red/255.0, color.green/255.0, color.blue/255.0);
cairo_fill (cr);
/* Draw the initials on top */
cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
layout = pango_cairo_create_layout (cr);
pango_layout_set_text (layout, initials, -1);
font_desc = pango_font_description_from_string (font);
pango_layout_set_font_description (layout, font_desc);
pango_font_description_free (font_desc);
pango_layout_get_size (layout, &width, &height);
cairo_translate (cr, size/2, size/2);
cairo_move_to (cr, - ((double)width / PANGO_SCALE)/2, - ((double)height/PANGO_SCALE)/2);
pango_cairo_show_layout (cr, layout);
cairo_destroy (cr);
return surface;
}
void
set_user_icon_data (ActUser *user,
GdkPixbuf *pixbuf)
{
gchar *path;
gint fd;
GOutputStream *stream;
GError *error;
path = g_build_filename (g_get_tmp_dir (), "gnome-control-center-user-icon-XXXXXX", NULL);
fd = g_mkstemp (path);
if (fd == -1) {
g_warning ("failed to create temporary file for image data");
g_free (path);
return;
}
stream = g_unix_output_stream_new (fd, TRUE);
error = NULL;
if (!gdk_pixbuf_save_to_stream (pixbuf, stream, "png", NULL, &error, NULL)) {
g_warning ("failed to save image: %s", error->message);
g_error_free (error);
g_object_unref (stream);
return;
}
g_object_unref (stream);
act_user_set_icon_file (user, path);
/* if we ever make the dbus call async, the g_remove call needs
* to wait for its completion
*/
g_remove (path);
g_free (path);
}
GdkPixbuf *
generate_default_avatar (ActUser *user, gint size)
{
GdkPixbuf *pixbuf = NULL;
cairo_surface_t *surface;
surface = generate_user_picture (act_user_get_real_name (user), size);
pixbuf = gdk_pixbuf_get_from_surface (surface, 0, 0, size, size);
cairo_surface_destroy (surface);
return pixbuf;
}
void
set_default_avatar (ActUser *user)
{
g_autoptr(GdkPixbuf) pixbuf = NULL;
pixbuf = generate_default_avatar (user, IMAGE_SIZE);
set_user_icon_data (user, pixbuf);
}