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/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
/* gcr-secure-buffer.c - secure memory gtkentry buffer
Copyright (C) 2009 Stefan Walter
The Gnome Keyring Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The Gnome Keyring Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the Gnome Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
Author: Stef Walter <stef@memberwebs.com>
*/
#include "config.h"
#include "gcr-secure-entry-buffer.h"
#include "egg/egg-secure-memory.h"
#include <string.h>
/**
* SECTION:gcr-secure-entry-buffer
* @title: GcrSecureEntryBuffer
* @short_description: a GtkEntryBuffer that uses non-pageable memory
*
* It's good practice to try to keep passwords or sensitive secrets out of
* pageable memory whenever possible, so that they don't get written to disk.
*
* This is a #GtkEntryBuffer to be used with #GtkEntry which uses non-pageable
* memory to store a password placed in the entry. In order to make any sense
* at all, the entry must have it's visibility turned off, and just be displaying
* place holder characters for the text. That is, a password style entry.
*
* Use gtk_entry_new_with_buffer() or gtk_entry_set_buffer() to set this buffer
* on an entry.
*/
/**
* GcrSecureEntryBuffer:
*
* A #GtkEntryBuffer which uses non-pageable memory for passwords or secrets.
*/
/**
* GcrSecureEntryBufferClass:
* @parent_class: parent class
*
* The class for #GcrSecureEntryBuffer.
*/
EGG_SECURE_DECLARE (secure_entry_buffer);
/* Initial size of buffer, in bytes */
#define MIN_SIZE 16
struct _GcrSecureEntryBufferPrivate
{
gchar *text;
gsize text_size;
gsize text_bytes;
guint text_chars;
};
G_DEFINE_TYPE (GcrSecureEntryBuffer, gcr_secure_entry_buffer, GTK_TYPE_ENTRY_BUFFER);
static const gchar *
gcr_secure_entry_buffer_real_get_text (GtkEntryBuffer *buffer,
gsize *n_bytes)
{
GcrSecureEntryBuffer *self = GCR_SECURE_ENTRY_BUFFER (buffer);
if (n_bytes)
*n_bytes = self->pv->text_bytes;
if (!self->pv->text)
return "";
return self->pv->text;
}
static guint
gcr_secure_entry_buffer_real_get_length (GtkEntryBuffer *buffer)
{
GcrSecureEntryBuffer *self = GCR_SECURE_ENTRY_BUFFER (buffer);
return self->pv->text_chars;
}
static guint
gcr_secure_entry_buffer_real_insert_text (GtkEntryBuffer *buffer,
guint position,
const gchar *chars,
guint n_chars)
{
GcrSecureEntryBuffer *self = GCR_SECURE_ENTRY_BUFFER (buffer);
GcrSecureEntryBufferPrivate *pv = self->pv;
gsize n_bytes;
gsize at;
n_bytes = g_utf8_offset_to_pointer (chars, n_chars) - chars;
/* Need more memory */
if (n_bytes + pv->text_bytes + 1 > pv->text_size) {
/* Calculate our new buffer size */
while (n_bytes + pv->text_bytes + 1 > pv->text_size) {
if (pv->text_size == 0) {
pv->text_size = MIN_SIZE;
} else {
if (2 * pv->text_size < GTK_ENTRY_BUFFER_MAX_SIZE) {
pv->text_size *= 2;
} else {
pv->text_size = GTK_ENTRY_BUFFER_MAX_SIZE;
if (n_bytes > pv->text_size - pv->text_bytes - 1) {
n_bytes = pv->text_size - pv->text_bytes - 1;
n_bytes = g_utf8_find_prev_char (chars, chars + n_bytes + 1) - chars;
n_chars = g_utf8_strlen (chars, n_bytes);
}
break;
}
}
}
pv->text = egg_secure_realloc (pv->text, pv->text_size);
}
/* Actual text insertion */
at = g_utf8_offset_to_pointer (pv->text, position) - pv->text;
g_memmove (pv->text + at + n_bytes, pv->text + at, pv->text_bytes - at);
memcpy (pv->text + at, chars, n_bytes);
/* Book keeping */
pv->text_bytes += n_bytes;
pv->text_chars += n_chars;
pv->text[pv->text_bytes] = '\0';
gtk_entry_buffer_emit_inserted_text (buffer, position, chars, n_chars);
return n_chars;
}
static guint
gcr_secure_entry_buffer_real_delete_text (GtkEntryBuffer *buffer,
guint position,
guint n_chars)
{
GcrSecureEntryBuffer *self = GCR_SECURE_ENTRY_BUFFER (buffer);
GcrSecureEntryBufferPrivate *pv = self->pv;
gsize start, end;
if (position > pv->text_chars)
position = pv->text_chars;
if (position + n_chars > pv->text_chars)
n_chars = pv->text_chars - position;
if (n_chars > 0) {
start = g_utf8_offset_to_pointer (pv->text, position) - pv->text;
end = g_utf8_offset_to_pointer (pv->text, position + n_chars) - pv->text;
g_memmove (pv->text + start, pv->text + end, pv->text_bytes + 1 - end);
pv->text_chars -= n_chars;
pv->text_bytes -= (end - start);
gtk_entry_buffer_emit_deleted_text (buffer, position, n_chars);
}
return n_chars;
}
static void
gcr_secure_entry_buffer_init (GcrSecureEntryBuffer *self)
{
GcrSecureEntryBufferPrivate *pv;
pv = self->pv = G_TYPE_INSTANCE_GET_PRIVATE (self, GCR_TYPE_SECURE_ENTRY_BUFFER, GcrSecureEntryBufferPrivate);
pv->text = NULL;
pv->text_chars = 0;
pv->text_bytes = 0;
pv->text_size = 0;
}
static void
gcr_secure_entry_buffer_finalize (GObject *obj)
{
GcrSecureEntryBuffer *self = GCR_SECURE_ENTRY_BUFFER (obj);
GcrSecureEntryBufferPrivate *pv = self->pv;
if (pv->text) {
egg_secure_strfree (pv->text);
pv->text = NULL;
pv->text_bytes = pv->text_size = 0;
pv->text_chars = 0;
}
G_OBJECT_CLASS (gcr_secure_entry_buffer_parent_class)->finalize (obj);
}
static void
gcr_secure_entry_buffer_class_init (GcrSecureEntryBufferClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
GtkEntryBufferClass *buffer_class = GTK_ENTRY_BUFFER_CLASS (klass);
gobject_class->finalize = gcr_secure_entry_buffer_finalize;
buffer_class->get_text = gcr_secure_entry_buffer_real_get_text;
buffer_class->get_length = gcr_secure_entry_buffer_real_get_length;
buffer_class->insert_text = gcr_secure_entry_buffer_real_insert_text;
buffer_class->delete_text = gcr_secure_entry_buffer_real_delete_text;
g_type_class_add_private (gobject_class, sizeof (GcrSecureEntryBufferPrivate));
}
/**
* gcr_secure_entry_buffer_new:
*
* Create a new #GcrSecureEntryBuffer, a #GtkEntryBuffer which uses
* non-pageable memory for the text.
*
* Returns: (transfer full): the new entry buffer
*/
GtkEntryBuffer *
gcr_secure_entry_buffer_new (void)
{
return g_object_new (GCR_TYPE_SECURE_ENTRY_BUFFER, NULL);
}
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