QubesOS/qubes-linux-utils
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity
b8b4e105c0
qubes-linux-utils/core/imgconverter.py
Wojciech Porczyk 59fb8daa03
site-packages/qubes/imgconverter.py 
This module does three things:
- secure image transfer protocol between VMs
- icon tinting for appmenus
- generic icon (padlock) generation
2014-01-14 16:04:03 +01:00

300 lines
9.9 KiB
Python
Executable File
Raw Blame History

#!/usr/bin/python2 -O
'''Qubes Image Converter
Toolkit for secure transfer and conversion of images between Qubes VMs.'''
# The Qubes OS Project, http://www.qubes-os.org
#
# Copyright (C) 2013 Wojciech Porczyk <wojciech@porczyk.eu>
#
# 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
import colorsys
import math
import os.path
import re
import cStringIO as StringIO
import subprocess
import sys
import unittest
import cairo
# those are for "zOMG UlTRa HD! WalLLpapPer 8K!!1!" to work seamlessly;
# 8192 * 5120 * 4 B = 160 MiB, so DoS by memory exhaustion is unlikely
MAX_WIDTH = 8192
MAX_HEIGHT = 5120
# current max raster icon size in hicolor theme is 256 as of 2013/fedora-18
# beyond that one probably shall use scalable icons
# (SVG is currently unsupported)
ICON_MAXSIZE = 512
# header consists of two decimal numbers, SPC and LF
re_imghdr = re.compile(r'^\d+ \d+\n$')
imghdrlen = lambda w, h: int(math.ceil(math.log10(w)) \
+ math.ceil(math.log10(h)) \
+ 2)
class Image(object):
def __init__(self, rgba, size):
'''This class is not meant to be instantiated directly. Use one of:
get_from_stream(), get_from_vm(), get_xdg_icon_from_vm(), get_through_dvm()'''
self._rgba = rgba
self._size = size
def save(self, dst):
'Save image to disk. dst may specify format, like png:aqq.gif'
p = subprocess.Popen(['convert',
'-depth', '8',
'-size', '{0[0]}x{0[1]}'.format(self._size),
'rgba:-', dst], stdin=subprocess.PIPE)
p.stdin.write(self._rgba)
p.stdin.close()
if p.wait():
raise Exception('Conversion failed')
def tint(self, colour):
'''Return new tinted image'''
r, g, b = hex_to_float(colour)
h, _, s = colorsys.rgb_to_hls(r, g, b)
result = StringIO.StringIO()
for i in xrange(0, self._size[0] * self._size[1] * 4, 4):
r, g, b, a = tuple(ord(c) / 255. for c in self._rgba[i:i+4])
_, l, _ = colorsys.rgb_to_hls(r, g, b)
r, g, b = colorsys.hls_to_rgb(h, l, s)
result.write(''.join(chr(int(i * 255)) for i in [r, g, b, a]))
return self.__class__(rgba=result.getvalue(), size=self._size)
@classmethod
def load_from_file(cls, filename):
'''Loads image from local file.
WARNING: always load trusted images.'''
p = subprocess.Popen(['identify', '-format', '%w %h', filename],
stdout=subprocess.PIPE)
size = tuple(int(i) for i in p.stdout.read().strip().split())
p.stdout.close()
p.wait()
p = subprocess.Popen(['convert', filename, '-depth', '8', 'rgba:-'],
stdout=subprocess.PIPE)
rgba = p.stdout.read()
p.stdout.close()
p.wait()
return cls(rgba=rgba, size=size)
@classmethod
def get_from_stream(cls, stream, max_width=MAX_WIDTH, max_height=MAX_HEIGHT):
'''Carefully parse image data from stream.
THIS METHOD IS SECURITY-SENSITIVE'''
maxhdrlen = imghdrlen(max_width, max_height)
untrusted_header = stream.readline(maxhdrlen)
if not re_imghdr.match(untrusted_header):
raise ValueError('Image format violation')
header = untrusted_header
del untrusted_header
untrusted_width, untrusted_height = (int(i) for i in header.rstrip().split())
if not (0 < untrusted_width <= max_width \
and 0 < untrusted_height <= max_height):
raise ValueError('Image size constraint violation:'
' width={width} height={height}'
' max_width={max_width} max_height={max_height}'.format(
width=untrusted_width, height=untrusted_height,
max_width=max_width, max_height=max_height))
width, height = untrusted_width, untrusted_height
del untrusted_width, untrusted_height
expected_data_len = width * height * 4 # RGBA
untrusted_data = stream.read(expected_data_len)
if len(untrusted_data) != expected_data_len:
raise ValueError( \
'Image data length violation (is {0}, should be {1})'.format( \
len(untrusted_data), expected_data_len))
data = untrusted_data
del untrusted_data
return cls(rgba=data, size=(width, height))
@classmethod
def get_from_vm(cls, vm, src, **kwargs):
'Get image from VM by QUBESRPC (qubes.GetImageRGBA).'
p = vm.run('QUBESRPC qubes.GetImageRGBA dom0', passio_popen=True)
p.stdin.write('{0}\n'.format(src))
p.stdin.close()
img = cls.get_from_stream(p.stdout, **kwargs)
p.stdout.close()
if p.wait():
raise Exception('Something went wrong with receiver')
return img
@classmethod
def get_xdg_icon_from_vm(cls, vm, icon, **kwargs):
'Get image from VM. If path is not absolute, get it from hicolor theme.'
if not os.path.isabs(icon):
icon = 'xdgicon:' + icon
return cls.get_from_vm(vm, icon,
max_width=ICON_MAXSIZE, max_height=ICON_MAXSIZE, **kwargs)
@classmethod
def get_through_dvm(cls, filename, **kwargs):
'''Master end of image filter: writes untrusted image to stdout and
expects header+RGBA on stdin. This method is invoked from qvm-imgconverter-client.'''
filetype = None
if ':' in filename:
filetype, filename = filename.split(':', 1)[0]
sys.stdout.write('{0}:-\n'.format(filetype))
else:
sys.stdout.write('-\n')
try:
sys.stdout.write(open(filename).read())
except Exception, e:
raise Exception('Something went wrong: {0!s}'.format(e))
finally:
sys.stdout.close()
return cls.get_from_stream(sys.stdin, **kwargs)
def hex_to_float(colour, channels=3, depth=8):
'''Convert hex colour definition to tuple of floats.'''
if depth % 4 != 0:
raise NotImplementedError('depths not divisible by 4 are unsupported')
length = channels * depth / 4
step = depth / 4
# get rid of '#' or '0x' in front of hex values
colour = colour[-length:]
return tuple(int(colour[i:i+step], 0x10) / float(2**depth - 1) for i in range(0, length, step))
def tint(src, dst, colour):
'''Tint image to reflect vm label.
src and dst may specify format, like png:aqq.gif'''
Image.load_from_file(src).tint(colour).save(dst)
def make_padlock(dst, colour, size=ICON_MAXSIZE):
cs = cairo.ImageSurface(cairo.FORMAT_ARGB32, size, size)
cr = cairo.Context(cs)
cr.set_source_rgb(*hex_to_float(colour))
cr.set_line_width(.125 * size)
cr.rectangle(.125 * size, .5 * size, .75 * size, .4375 * size)
cr.fill()
cr.move_to(.25 * size, .5 * size)
cr.line_to(.25 * size, .375 * size)
cr.arc(.5 * size, .375 * size, .25 * size, math.pi, 2 * math.pi)
cr.move_to(.75 * size, .375 * size) # this is unneccessary, but helps readability
cr.line_to(.75 * size, .5 * size)
cr.stroke()
cs.write_to_png(dst)
class TestCaseImage(unittest.TestCase):
def setUp(self):
self.rgba = \
'\x00\x00\x00\xff' '\xff\x00\x00\xff' \
'\x00\xff\x00\xff' '\x00\x00\x00\xff'
self.size = (2, 2)
self.image = Image(rgba=self.rgba, size=self.size)
def test_00_init(self):
self.assertEqual(self.image._rgba, self.rgba)
self.assertEqual(self.image._size, self.size)
def test_01_tint(self):
image = self.image.tint('#0000ff')
self.assertEqual(image._rgba,
'\x00\x00\x00\xff' '\x00\x00\xff\xff'
'\x00\x00\xff\xff' '\x00\x00\x00\xff')
def test_10_get_from_stream(self):
io = StringIO.StringIO('{0[0]} {0[1]}\n{1}'.format(self.size, self.rgba))
image = Image.get_from_stream(io)
self.assertEqual(image._rgba, self.rgba)
self.assertEqual(image._size, self.size)
def test_11_get_from_stream_malformed(self):
io = StringIO.StringIO('{0[0]} {0[1]}\n{1}'.format(self.size, self.rgba[-1])) # one byte too short
with self.assertRaises(Exception):
image = Image.get_from_stream(io)
def test_12_get_from_stream_too_big(self):
io = StringIO.StringIO('{0[0]} {0[1]}\n{1}'.format(self.size, self.rgba)) # 2x2
with self.assertRaises(Exception):
image = Image.get_from_stream(io, max_width=1)
io.seek(0)
with self.assertRaises(Exception):
image = Image.get_from_stream(io, max_height=1)
class TestCaseFunctionsAndConstants(unittest.TestCase):
def test_00_imghdrlen(self):
self.assertEqual(imghdrlen(8, 15), len('8 15\n'))
def test_01_re_imghdr(self):
self.assertTrue(re_imghdr.match('8 15\n'))
self.assertIsNone(re_imghdr.match('8 15'))
self.assertIsNone(re_imghdr.match('815\n'))
self.assertIsNone(re_imghdr.match('x yx\n'))
def test_10_hex_to_float_result_00(self):
self.assertEqual(hex_to_float('#000000'), (0.0, 0.0, 0.0))
def test_11_hex_to_float_result_ff(self):
self.assertEqual(hex_to_float('0xffffff'), (1.0, 1.0, 1.0))
def test_12_hex_to_float_depth_3_not_implemented(self):
with self.assertRaises(NotImplementedError):
hex_to_float('123456', depth=3)
if __name__ == '__main__':
unittest.main()
# vim: ft=python sw=4 ts=4 et
Reference in New Issue View Git Blame Copy Permalink