Add support for loading RDI-related stuff using ordinals instead of
function names. Remove exports from the extensions/etc. This is another
step in the direction to make the DLLs less obvious.
Extensions no longer have their own name in the library metadata.
They're all "extension.dll". Metsrv is now "server.dll" and the two
non-extensions are "plugin.dll". I was going for something a little less
obvious.
This required changes to the RDI functionality.
Enumeration of commands was a bit of a hack, and still resultsed in
strings (like "stdapi") to appear in binaries, and also meant that
extensions needed to identify themselves.
This code changes the way this works. Extensions no longer have a name.
Instead they have an internal ID tha maps to the command sets they
support. To enumerate extension commands, MSF will ask for a range of
commands, and if any command IDs fit within that range, they'll be
returned.
This moves us towards a nicer way of handling things across all the
meterpreters.
We now use ints, and hopefully this means we don't have as much obvious
stuff in the binaries!
```
$ # Before:
$ strings metsrv.x86.dll | grep core_ | wc -l
46
$ # After:
$ strings metsrv.x86.dll | grep core_ | wc -l
0
```
Big win, and it's even bigger for the likes of stdapi.
Had to fix a bunch of other stuff along the way, including a subtle
issue with the Powershell Meterp bindings.
The 'common' library has been removed. The only project that actually
used it was metsrv, so the code that metsrv required from common is now
directly compiled in as part of that project.
The common folder now contains files that are importanta cross all of
the projects, with a primary focus on the new "API" style function. What
this means is that MetSrv has an API that it exposes through a function
pointer that is passed to the extension when it's initialised. This
pointer references a structure with all the API functions wired in. This
means that:
* Extensions don't need to know anything about metsrv at compile time.
* The delay loading code can be removed, which was one of the last
instances of "metsrv.dll" as a string.
* Metsrv.dll no longer exports any functions.
More to come.
* Make sure POSIX has the new extension command enumeration function.
* Add support for deinit of extensions.
* Make sure extensions are tracked like they in Windows.
* Fix up a few export definitions.
* Stop using strncpy_s in POSIX code.
This commit contains a bunch of code tidying (formatting, spaces, naming, etc) as well as new exports for each of the modules so that the extension can be identified. The plan is for the loader to know which modules are loaded so that when stageless meterpreter fires up MSF can query the existing extensions and load the appropriate functionality on the client side.
This adds registry access methods that do an atomic open/<action>/close on
registry keys. They improve efficiency and safety, since we're not passing
HKEY's back and forth to enumerate or read registry keys. This fits the common
use pattern in MSF better anyway.
Added support for a the getsid command so that it's easy to
determine the SID of the current user. This will be useful for
a number of different use cases.
A few minor issues around formatting collisions, nothing huge.
.gitignore fixes too
Conflicts:
source/common/base_dispatch_common.c
source/extensions/stdapi/server/stdapi.c
This is a new command in the stdapi which allows the caller to pass in a set of
environment variable names and retrieve a hash of the names and values.
MSF side has been attempting to open keys to see if they exist, which isn't
fantastic as it results in an error. This change adds a function which indicates
to the caller if the given reg key exists.
Fixed up the cusom command declarations in the sniffer extension so
that they're using the new macros. I don't know how they were missed.
Various bits of tidying up, while trying to sort out the sniffer prob.
This work contains a bunch of changes around command dispatching. The
goals for this bit of work were to:
* Provide the ability for commands to be executed on the same thread as
the server rather than always creating new threads and executing them on
those threads.
* Have the means for _special_ commands, such as `exit` and `migrate` to
shut down the server cleanly without having to rely on signalling across
threads or by doing brutal thread termination via shared global handles.
This should not only fix the dirty shutdown problem on Windows which
leaves tasks dangling (or based on the prior attempt at fixing, crashing
stuff as well), it should also help clean up the shutdown process in
POSIX.
These changes hit a very important part of Meterpreter and so should be
reviewed with intense scrutnity. I expect this PR to garner a log of
critique and most likely a number of changes before being included in the
main line.
The `PacketDispatcher` was modified to include a new function pointer
called an `inline_handler`. This new member indicates that there's a
handler which should be invoked inline. While this sits alongside the
existing `handler`, they are actually mutually exclusive. If an
`inline_handler` is specified then the `handler` is ignored and it is
assumed that the command is intended to be handled inline. The signature
of the inline handler is different to the standard handler, and this is
why a new function pointer was added rather than a simple flag. Addition of
this parameter meant that the basic command structure changed, and that
obviously affects all of the extensions and their respective commands.
This changeset therefore updates each of those command declarations so
that they use the new macros that hide this detail.
Other things to be mindful of:
* This version of the code reads the command's `method` prior to invoking
any other function, and after that the command itself is passed around to
the threaded or non-threaded routes for invocation. An extra thread
parameter was included as as result, and an overload for the
`thread_create` function was added which supported this new parameter.
This was named `thread_create3` because
`thread_create_with_another_paramter` sounded a bit crap.
* The migration code, which originally had a `thread_kill` and an event
wait once the new meterpreter session had been created, has been modified
to not do any waiting at all. Instead it finishes execution as fast as
possible and returns control to the server which should respond by
shutting down in a clean way.
* Originally the code always attempted to call a command handler in the
base command list and then, if found, would also call an "overload" in
the extension commands list. From the investigation that I did, it
appears that the overloaded methods did nothing in the base (they'd
early out during invocation). As a result, the new way of doing things
acts like a 'true' overload in that the extension commands are searched
first, and if one is found this is the command that is executed. Any
base commands with the same method name will not get executed. In the
case where there is no extension command found, the base command list is
then queried. If a command is found that command is instead invoked.
* The POSIX version still compiles cleanly, but I've never been able to
build a version that runs on my machines. I'm not sure if there's a
trick to getting POSIX builds to run, and if there is I don't know it.
Whoever scrutinises this build should make sure that the POSIX version
that they build can still run and (hopefully) exit cleanly.
I've added lots of documentation, but there's always room for improvement.
Hopefully this will fix the `*_tcp` side of Redmine 8438.
Bring on the feedback!
