gtk2/gtk/gtkiconcachevalidator.c

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/* gtkiconcachevalidator.c
* Copyright (C) 2007 Red Hat, Inc
*
* This 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.
*
* This 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 this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include "config.h"
#include "gtkiconcachevalidator.h"
#include <glib.h>
#include <gdk-pixbuf/gdk-pixdata.h>
#define VERBOSE(x)
#define check(name,condition) \
if (!(condition)) \
{ \
VERBOSE(g_print ("bad %s\n", (name))); \
return FALSE; \
}
static inline gboolean
get_uint16 (CacheInfo *info,
guint32 offset,
guint16 *value)
{
if (offset < info->cache_size)
{
*value = GUINT16_FROM_BE(*(guint16*)(info->cache + offset));
return TRUE;
}
else
{
*value = 0;
return FALSE;
}
}
static inline gboolean
get_uint32 (CacheInfo *info,
guint32 offset,
guint32 *value)
{
if (offset < info->cache_size)
{
*value = GUINT32_FROM_BE(*(guint32*)(info->cache + offset));
return TRUE;
}
else
{
*value = 0;
return FALSE;
}
}
static gboolean
check_version (CacheInfo *info)
{
guint16 major, minor;
check ("major version", get_uint16 (info, 0, &major) && major == 1);
check ("minor version", get_uint16 (info, 2, &minor) && minor == 0);
return TRUE;
}
static gboolean
check_string (CacheInfo *info,
guint32 offset)
{
check ("string offset", offset < info->cache_size);
if (info->flags & CHECK_STRINGS)
{
gint i;
gchar c;
/* assume no string is longer than 1k */
for (i = 0; i < 1024; i++)
{
check ("string offset", offset + i < info->cache_size)
c = *(info->cache + offset + i);
if (c == '\0')
break;
check ("string content", g_ascii_isgraph (c));
}
check ("string length", i < 1024);
}
return TRUE;
}
static gboolean
check_string_utf8 (CacheInfo *info,
guint32 offset)
{
check ("string offset", offset < info->cache_size);
if (info->flags & CHECK_STRINGS)
{
gint i;
gchar c;
/* assume no string is longer than 1k */
for (i = 0; i < 1024; i++)
{
check ("string offset", offset + i < info->cache_size)
c = *(info->cache + offset + i);
if (c == '\0')
break;
}
check ("string length", i < 1024);
check ("string utf8 data", g_utf8_validate((char *)(info->cache + offset), -1, NULL));
}
return TRUE;
}
static gboolean
check_directory_list (CacheInfo *info,
guint32 offset)
{
guint32 directory_offset;
gint i;
check ("offset, directory list", get_uint32 (info, offset, &info->n_directories));
for (i = 0; i < info->n_directories; i++)
{
check ("offset, directory", get_uint32 (info, offset + 4 + 4 * i, &directory_offset));
if (!check_string (info, directory_offset))
return FALSE;
}
return TRUE;
}
static gboolean
check_pixel_data (CacheInfo *info,
guint32 offset)
{
guint32 type;
guint32 length;
check ("offset, pixel data type", get_uint32 (info, offset, &type));
check ("offset, pixel data length", get_uint32 (info, offset + 4, &length));
check ("pixel data type", type == 0);
check ("pixel data length", offset + 8 + length < info->cache_size);
if (info->flags & CHECK_PIXBUFS)
{
GdkPixdata data;
check ("pixel data", gdk_pixdata_deserialize (&data, length,
info->cache + offset + 8,
NULL));
}
return TRUE;
}
static gboolean
check_embedded_rect (CacheInfo *info,
guint32 offset)
{
check ("embedded rect", offset + 4 < info->cache_size);
return TRUE;
}
static gboolean
check_attach_point_list (CacheInfo *info,
guint32 offset)
{
guint32 n_attach_points;
check ("offset, attach point list", get_uint32 (info, offset, &n_attach_points));
check ("attach points", offset + 4 + 4 * n_attach_points < info->cache_size);
return TRUE;
}
static gboolean
check_display_name_list (CacheInfo *info,
guint32 offset)
{
guint32 n_display_names, ofs;
gint i;
check ("offset, display name list",
get_uint32 (info, offset, &n_display_names));
for (i = 0; i < n_display_names; i++)
{
get_uint32(info, offset + 4 + 8 * i, &ofs);
if (!check_string (info, ofs))
return FALSE;
get_uint32(info, offset + 4 + 8 * i + 4, &ofs);
if (!check_string_utf8 (info, ofs))
return FALSE;
}
return TRUE;
}
static gboolean
check_meta_data (CacheInfo *info,
guint32 offset)
{
guint32 embedded_rect_offset;
guint32 attach_point_list_offset;
guint32 display_name_list_offset;
check ("offset, embedded rect",
get_uint32 (info, offset, &embedded_rect_offset));
check ("offset, attach point list",
get_uint32 (info, offset + 4, &attach_point_list_offset));
check ("offset, display name list",
get_uint32 (info, offset + 8, &display_name_list_offset));
if (embedded_rect_offset != 0)
{
if (!check_embedded_rect (info, embedded_rect_offset))
return FALSE;
}
if (attach_point_list_offset != 0)
{
if (!check_attach_point_list (info, attach_point_list_offset))
return FALSE;
}
if (display_name_list_offset != 0)
{
if (!check_display_name_list (info, display_name_list_offset))
return FALSE;
}
return TRUE;
}
static gboolean
check_image_data (CacheInfo *info,
guint32 offset)
{
guint32 pixel_data_offset;
guint32 meta_data_offset;
check ("offset, pixel data", get_uint32 (info, offset, &pixel_data_offset));
check ("offset, meta data", get_uint32 (info, offset + 4, &meta_data_offset));
if (pixel_data_offset != 0)
{
if (!check_pixel_data (info, pixel_data_offset))
return FALSE;
}
if (meta_data_offset != 0)
{
if (!check_meta_data (info, meta_data_offset))
return FALSE;
}
return TRUE;
}
static gboolean
check_image (CacheInfo *info,
guint32 offset)
{
guint16 index;
guint16 flags;
guint32 image_data_offset;
check ("offset, image index", get_uint16 (info, offset, &index));
check ("offset, image flags", get_uint16 (info, offset + 2, &flags));
check ("offset, image data offset",
get_uint32 (info, offset + 4, &image_data_offset));
check ("image index", index < info->n_directories);
check ("image flags", flags < 16);
if (image_data_offset != 0)
{
if (!check_image_data (info, image_data_offset))
return FALSE;
}
return TRUE;
}
static gboolean
check_image_list (CacheInfo *info,
guint32 offset)
{
guint32 n_images;
gint i;
check ("offset, image list", get_uint32 (info, offset, &n_images));
for (i = 0; i < n_images; i++)
{
if (!check_image (info, offset + 4 + 8 * i))
return FALSE;
}
return TRUE;
}
static gboolean
check_icon (CacheInfo *info,
guint32 offset)
{
guint32 chain_offset;
guint32 name_offset;
guint32 image_list_offset;
check ("offset, icon chain", get_uint32 (info, offset, &chain_offset));
check ("offset, icon name", get_uint32 (info, offset + 4, &name_offset));
check ("offset, icon image list", get_uint32 (info, offset + 8,
&image_list_offset));
if (!check_string (info, name_offset))
return FALSE;
if (!check_image_list (info, image_list_offset))
return FALSE;
if (chain_offset != 0xffffffff)
{
if (!check_icon (info, chain_offset))
return FALSE;
}
return TRUE;
}
static gboolean
check_hash (CacheInfo *info,
guint32 offset)
{
guint32 n_buckets, icon_offset;
gint i;
check ("offset, hash size", get_uint32 (info, offset, &n_buckets));
for (i = 0; i < n_buckets; i++)
{
check ("offset, hash chain",
get_uint32 (info, offset + 4 + 4 * i, &icon_offset));
if (icon_offset != 0xffffffff)
{
if (!check_icon (info, icon_offset))
return FALSE;
}
}
return TRUE;
}
/**
* _gtk_icon_cache_validate:
* @info: a CacheInfo structure
*
* Validates the icon cache passed in the @cache and
* @cache_size fields of the @info structure. The
* validator checks that offsets specified in the
* cache do not point outside the mapped area, that
* strings look reasonable, and that pixbufs can
* be deserialized. The amount of validation can
* be controlled with the @flags field.
*
* Return value: %TRUE if the cache is valid
*/
gboolean
_gtk_icon_cache_validate (CacheInfo *info)
{
guint32 hash_offset;
guint32 directory_list_offset;
if (!check_version (info))
return FALSE;
check ("header, hash offset", get_uint32 (info, 4, &hash_offset));
check ("header, directory list offset", get_uint32 (info, 8, &directory_list_offset));
if (!check_directory_list (info, directory_list_offset))
return FALSE;
if (!check_hash (info, hash_offset))
return FALSE;
return TRUE;
}