From d31c937c566005dedf41a60c6b5bd5e7b26f221b Mon Sep 17 00:00:00 2001
From: Eric Harney <eharney@redhat.com>
Date: Tue, 31 Mar 2015 19:48:17 -0400
Subject: [PATCH] Disallow backing files when uploading volumes to image

Volumes with a header referencing a backing file can leak
file data into the destination image when uploading a
volume to an image.

Halt the upload process if the volume data references a
backing file to prevent this.

Closes-Bug: #1415087
Change-Id: Iab9718794e7f7e8444015712cfa08c46848ebf78
(cherry picked from commit 9634b76ba5886d6c2f2128d550cb005dabf48213)
Conflicts:
    cinder/tests/test_image_utils.py (backport to old tests)
---
 cinder/image/image_utils.py      | 14 ++++++++++++++
 cinder/tests/test_image_utils.py | 13 +++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/cinder/image/image_utils.py b/cinder/image/image_utils.py
index 160dfe7..cac0072 100644
--- a/cinder/image/image_utils.py
+++ b/cinder/image/image_utils.py
@@ -312,6 +312,20 @@ def upload_volume(context, image_service, image_meta, volume_path,
     with fileutils.remove_path_on_error(tmp):
         LOG.debug("%s was %s, converting to %s" %
                   (image_id, volume_format, image_meta['disk_format']))
+
+        data = qemu_img_info(volume_path)
+        backing_file = data.backing_file
+        fmt = data.file_format
+        if backing_file is not None:
+            # Disallow backing files as a security measure.
+            # This prevents a user from writing an image header into a raw
+            # volume with a backing file pointing to data they wish to
+            # access.
+            raise exception.ImageUnacceptable(
+                image_id=image_id,
+                reason=_("fmt=%(fmt)s backed by:%(backing_file)s")
+                % {'fmt': fmt, 'backing_file': backing_file})
+
         convert_image(volume_path, tmp, image_meta['disk_format'],
                       bps_limit=CONF.volume_copy_bps_limit)
 
diff --git a/cinder/tests/test_image_utils.py b/cinder/tests/test_image_utils.py
index 86168c0..2cf571a 100644
--- a/cinder/tests/test_image_utils.py
+++ b/cinder/tests/test_image_utils.py
@@ -462,6 +462,10 @@ def test_upload_volume(self, mock_stat, bps_limit=0):
         volume_utils.setup_blkio_cgroup(mox.IgnoreArg(), mox.IgnoreArg(),
                                         bps_limit).AndReturn(prefix)
 
+        utils.execute(
+            'env', 'LC_ALL=C', 'qemu-img', 'info',
+            mox.IgnoreArg(), run_as_root=True).AndReturn(
+                (TEST_RET, 'ignored'))
         utils.execute(*cmd, run_as_root=True)
         utils.execute(
             'env', 'LC_ALL=C', 'qemu-img', 'info',
@@ -497,6 +501,11 @@ def test_upload_volume_with_bps_limit(self, mock_stat):
 
         volume_utils.setup_blkio_cgroup(mox.IgnoreArg(), mox.IgnoreArg(),
                                         bps_limit).AndReturn(prefix)
+
+        utils.execute(
+            'env', 'LC_ALL=C', 'qemu-img', 'info',
+            mox.IgnoreArg(), run_as_root=True).AndReturn(
+                (TEST_RET, 'ignored'))
         utils.execute(*cmd, run_as_root=True)
         utils.execute(
             'env', 'LC_ALL=C', 'qemu-img', 'info',
@@ -534,6 +543,10 @@ def test_upload_volume_on_error(self, mock_stat):
         m.StubOutWithMock(utils, 'execute')
         m.StubOutWithMock(volume_utils, 'check_for_odirect_support')
 
+        utils.execute(
+            'env', 'LC_ALL=C', 'qemu-img', 'info',
+            mox.IgnoreArg(), run_as_root=True).AndReturn(
+                (TEST_RET, 'ignored'))
         utils.execute('qemu-img', 'convert', '-O', 'qcow2',
                       mox.IgnoreArg(), mox.IgnoreArg(), run_as_root=True)
         utils.execute(