Libguestfs - Mar 2011 - Python Hivex Assertion Failed

Good afternoon,

I am working with the hivex python bindings and having trouble with an
assertion failure.

The code I run is based on the blog post from 11/28/10 and is:

import hivex
h = hivex.Hivex("ntuser.dat")
r = h.root()
key = h.node_get_child(r)

The assert failure happens when I call any of the "node" functions,
even "node_name()".

The error message I get each time is:
python: hivex-py.c:52: get_handle:
    Assertion 'obj' failed

When I print r (h.root() result), I get a long integer "4128".  (Which
makes sense -- that would be shortly into the second bin, where the
root of the hive should be).  The hivex.3 man page indicates that the
return value for the root() function should be a handle, aka integer,
so it seems to be right.

I don't think it's the hive -- i tried a couple different ones, albeit
all from the same machine.  I also ran it with a perl based registry
library and it was fine.

I'm using Ubuntu and python 2.6.

Any suggestions on what the problem might be?  Thanks!

Elizabeth

On Thu, Mar 31, 2011 at 01:17:19PM -0400, Elizabeth Schweinsberg
wrote:
> Good afternoon,
> 
> I am working with the hivex python bindings and having trouble with an
> assertion failure.
> 
> The code I run is based on the blog post from 11/28/10 and is:
> 
> import hivex
> h = hivex.Hivex("ntuser.dat")
> r = h.root()
> key = h.node_get_child(r)
node_get_child needs 2 args there, and it returns a node (not a "key"
although the terminology for Registry entries is confusing and
contradictory).  You probably mean something like:

  node = h.node_get_child (r, "foo")

where "foo" is the case-insensitive name of the child you want to get.
> The assert failure happens when I call any of the "node"
functions,
> even "node_name()".
> 
> The error message I get each time is:
> python: hivex-py.c:52: get_handle:
>     Assertion 'obj' failed
> 
> When I print r (h.root() result), I get a long integer "4128". 
(Which
> makes sense -- that would be shortly into the second bin, where the
> root of the hive should be).  The hivex.3 man page indicates that the
> return value for the root() function should be a handle, aka integer,
> so it seems to be right.
> 
> I don't think it's the hive -- i tried a couple different ones,
albeit
> all from the same machine.  I also ran it with a perl based registry
> library and it was fine.
> 
> I'm using Ubuntu and python 2.6.
> 
> Any suggestions on what the problem might be?  Thanks!
How are you calling node_name?  Note that the Python API isn't really
"object oriented", it's just the C API translated literally into
Python.  All "methods" are part of the hivex base class, and there are
no other classes.  Therefore:

  s = r.node_name() // wrong
  s = h.node_name (r) // correct

This program works for me:

----------------------------------------------------------------------
#!/usr/bin/python
import hivex
h = hivex.Hivex ("/tmp/software")
r = h.root ()
node = h.node_get_child (r, "Microsoft")
print r
print h.node_name (r)
print h.node_name (node)
----------------------------------------------------------------------

----------------------------------------------------------------------
$ chmod +x /tmp/test.py
$ /tmp/test.py
4128
CMI-CreateHive{199DAFC2-6F16-4946-BF90-5A3FC3A60902}
Microsoft
----------------------------------------------------------------------

hivex-1.2.4-7.fc15.x86_64
python-2.7.1-6.fc15.x86_64

The "name" of the root node isn't necessarily something that makes
sense.  There is a note about this in the man page.

If you can't make it work, please send a more complete example, and if
you think the fault lies in the hive itself, then put the hive online.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
libguestfs lets you edit virtual machines.  Supports shell scripting,
bindings from many languages.  http://libguestfs.org

On Fri, Apr 01, 2011 at 03:01:58PM -0400, Elizabeth Schweinsberg
wrote:
> Richard,
> 
> Thanks for the reply.  I'm beginning to think it's Ubuntu
that's the
> problem.  I acquired a SOFTWARE hive and ran the code you sent on it
> and I get the same error.  I even upgraded to Python 2.7.
> 
> My runs:
> 
> -------- Your code with my software hive --------
> emschwe at station12:~/jean2$ cat test-hivex.py
> #!/usr/bin/python
> import hivex
> h = hivex.Hivex("software")
> r = h.root()
> node = h.node_get_child(r, "Microsoft")
> print r
> print h.node_name(r)
> print h.node_name(node)
> 
> emschwe at station12:~/jean2$ ./test-hivex.py
> python: hivex-py.c:52: get_handle: Assertion `obj' failed.
> Aborted
> emschwe at station12:~/jean2$
> 
> 
> ----- My version on NTUSER.DAT -----
> emschwe at station12:~/jean2$ cat test-hivex.py
> #!/usr/bin/python
> import hivex
> h = hivex.Hivex("NTUSER.004.DAT")
> r = h.root()
> node = h.node_get_child(r, "Software")
> print r
> print h.node_name(r)
> print h.node_name(node)
> 
> emschwe at station12:~/jean2$ ./test-hivex.py
> python: hivex-py.c:52: get_handle: Assertion `obj' failed.
> Aborted
> emschwe at station12:~/jean2$
> 
> I uploaded the NTUSER.DAT file here:
> 
> [...]
I cannot get to that URL.  It wants me to log in or something.
> If you are able to process it on your system, then I'll know it's
the
> installation and I should start all over (again).
Which version are you running?  The Ubuntu version in universe doesn't
even have any Python bindings.  Are you compiling it from source?

Please let's keep replies on the list to benefit others who might come
across the same problem.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-p2v converts physical machines to virtual machines.  Boot with a
live CD or over the network (PXE) and turn machines into Xen guests.
http://et.redhat.com/~rjones/virt-p2v