Initial working version.

.gitignore

@@ -262,3 +262,6 @@ __pycache__/
 
 # Ubuntu headers (for IntelliSense)
 /linux/include
+
+# Release packages
+/*.zip

COPYING.PuTTY

@@ -0,0 +1,29 @@
+Part of weasel-pageant is derived from the PuTTY program, whose original
+license is reproduced below.
+
+
+PuTTY is copyright 1997-2011 Simon Tatham.
+
+Portions copyright Robert de Bath, Joris van Rantwijk, Delian
+Delchev, Andreas Schultz, Jeroen Massar, Wez Furlong, Nicolas Barry,
+Justin Bradford, Ben Harris, Malcolm Smith, Ahmad Khalifa, Markus
+Kuhn, Colin Watson, and CORE SDI S.A.
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation files
+(the "Software"), to deal in the Software without restriction,
+including without limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of the Software,
+and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE
+FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
+CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.md

@@ -0,0 +1,171 @@
+weasel-pageant
+--------------
+
+`weasel-pageant` allows you to use SSH keys held by [PuTTY's](https://www.chiark.greenend.org.uk/~sgtatham/putty/)
+Pageant "daemon" (or compatible, such as the version of Pageant included in 
+[PuTTY-CAC](https://github.com/NoMoreFood/putty-cac) or the SSH agent mode in
+[Gpg4win](https://www.gpg4win.org/)) from inside the
+[Windows Subsystem for Linux](https://msdn.microsoft.com/en-us/commandline/wsl/about).
+
+The source (and this documentation) is heavily based on
+[`ssh-pageant`](https://github.com/cuviper/ssh-pageant) 1.4 by Josh Stone, which allows
+interacting with Pageant from Cygwin/MSYS programs.
+
+`weasel-pageant` works like `ssh-agent`, except that it leaves the key storage to
+PuTTY's Pageant.  It sets up an authentication socket and prints the environment
+variables, which allows the OpenSSH client to use it. It works by executing from the
+WSL side a Win32 helper program which interfaces with Pageant and communicating with
+it through pipes.
+
+It is probably the most useful if your SSH keys can't be copied to the WSL environment,
+such as when using a smart card for SSH authentication. Both Pageant-CAC and Gpg4win
+have been tested (note that when using Gpg4win, only the SSH authentication functionality
+will be forwarded; the Windows-side `gpg-agent` will not be available on the WSL side).
+
+**SECURITY NOTICE:** All the usual security caveats applicable to WSL apply here too.
+Most importantly, all interaction with the Win32 world happens with the credentials of
+the user who started the WSL environment. In practice, *if you allow someone else to
+log in to your WSL environment remotely, they can access the SSH keys stored in your
+Pageant with `weasel-pageant`.* This is a fundamental part of how WSL works; if you
+are not sure of what you're doing, do not  allow remote access to your WSL enviroment
+(i.e. by starting an SSH server).
+
+**COMPATIBILITY NOTICE:** `weasel-pageant` does not, and will never work on
+a version of Windows 10 older than 1703 ("Creators Update"), because
+it requires the new [Windows/Ubuntu interoperability support](https://blogs.msdn.microsoft.com/wsl/2016/10/19/windows-and-ubuntu-interoperability/)
+feature shipped with version 1703 (compatibility with older Insider
+builds is unclear). Presumably it should work with newer Insider builds,
+but has not been tested on anything more recent than build 15063.413.
+
+If you are still using Anniversary Update, you may be able to use the (unrelated)
+[wsl-ssh-pageant](https://github.com/benpye/wsl-ssh-pageant).
+
+## Installation
+
+### From binaries
+
+Download the zip file from the releases page and unpack it in a convenient location
+*on the Windows part of your drive*. Because WSL can only execute Win32 binaries from
+`drvfs` locations, `weasel-pageant` *will not work* if unpacked inside the WSL
+filesystem (onto an `lxfs` mount). (Advanced users may place only `helper.exe` on
+`drvfs`, but in general it is easier to keep the pieces together.)
+
+### From source
+
+A VS2017 project is included. You will need the "Desktop development with C++" and
+"Linux development with C++" features.
+
+1. In VS2017, set up a connection to your WSL environment (or a remote Linux machine)
+   in Options → Cross Platform → Connection Manager.
+
+2. Optional: If you intend to work on the Linux sources, copy the contents of
+   `/usr/include` into `weasel-pageant/include` under the project directory.
+   This is not required for the build, but will make Intellisense more useful.
+
+3. Hit Build Solution and both the Linux executable and the Win32 helper will be built.
+
+If you want to create a binary package, you can use the `create_pkg.py` script
+at the root of the project. This should work with Python 3.4 or newer on either
+Windows or Linux.
+
+Alternatively you can build the Linux executable directly on Linux and only use
+Visual Studio for the Win32 helper (no Makefile or similar is supplied at the moment).
+In theory the helper should be buildable with MinGW-w64 for a fully Linux-based
+build, but this has not been tested.
+
+The release binaries have been built with VS2017 15.3.0 Preview 2.0.
+
+## Usage
+
+Using `weasel-pageant` is generally similar to using `ssh-agent` on Linux and
+similar operating systems. 
+
+1. Ensure that PuTTY's Pageant is running (and holds your SSH keys).
+    * ssh-pageant does not start Pageant itself.
+    * Recommended: Add Pageant to your Windows startup/Autostart configuration
+      so it is always available.
+
+2. Edit your `~/.bashrc` (or `~/.bash_profile`) to add the following:
+
+        eval $(<location where you unpacked the zip>/weasel-pageant -r -a "/tmp/.weasel-pageant-$USERNAME")
+
+    To explain:
+
+    * This leverages the `-r`/`--reuse` option in combination with `-a SOCKET`,
+      which will only start a new daemon if the specified path does not accept connections
+      already.  If the socket appears to be active, it will just set `SSH_AUTH_SOCK` and exit.
+
+    * The exact path used for `-a` is arbitrary.  The socket will be created
+      with only user-accessible permissions, but you may still want to use a more
+      private path than shown above if multiple users can access your WSL instance.
+
+    * When using this, the `weasel-pageant` daemon and its helper process `helper.exe`
+      remains active (both will be visible in the Windows task manager).  You should not
+      kill these processes, since open shells might still be using the socket. 
+
+    * Using `eval` will set the environment variables in the current shell.
+      By default, `weasel-pageant` tries to detect the current shell and output
+      appropriate commands. If detection fails, then use the `-S SHELL` option
+      to define a shell type manually.
+
+3. Restart your shell or type (when using bash) `. ~/.bashrc`. Typing `ssh-add -l`
+   should now list the keys you have registered in Pageant.
+
+## Options
+
+`weasel-pageant` aims to be compatible with `ssh-agent` options, with a few extras:
+
+    $ weasel-pageant -h
+    Usage: weasel-pageant [options] [command [arg ...]]
+    Options:
+      -h, --help     Show this help.
+      -v, --version  Display version information.
+      -c             Generate C-shell commands on stdout.
+      -s             Generate Bourne shell commands on stdout.
+      -S SHELL       Generate shell command for "bourne", "csh", or "fish".
+      -k             Kill the current weasel-pageant.
+      -d             Enable debug mode.
+      -q             Enable quiet mode.
+      -a SOCKET      Create socket on a specific path.
+      -r, --reuse    Allow to reuse an existing -a SOCKET.
+      -H, --helper   Path to the Win32 helper binary (default: /mnt/c/Program Files/weasel-pageant/helper.exe).
+      -t TIME        Limit key lifetime in seconds (not supported by Pageant).
+
+By default, the Win32 helper will be searched for in the same directory where `weasel-pageant`
+is stored. If you have placed it elsewhere, the `-H` flag can be used to set the location.
+
+## Known issues
+
+* The Win32 helper cannot be restarted if it's killed or crashes. There appears to be a bug
+  in WSL that causes pipes passed to Win32 executables to be unusable after some point
+  in program execution (possibly related to forking processes or opening sockets). Currently,
+  `weasel-pageant` will exit if it detects that the helper has exited.
+
+## Uninstallation
+
+To uninstall, just remove the extracted files and any modifications you made
+to your shell initialization files (i.e. `.bashrc`).
+
+## Version History
+
+* 2017-06-25: 1.0 - Initial release.
+
+## Contributions
+
+Please send bug reports using Github's Issues feature. Pull requests are also
+welcome, though if you intend to do major changes it's recommended to open an
+issue first.
+
+------------------------------------------------------------------------------
+Copyright 2017  Valtteri Vuorikoski
+
+Based on `ssh-pageant`, copyright (C) 2009-2014  Josh Stone  
+
+Licensed under the GNU GPL version 3 or later, http://gnu.org/licenses/gpl.html
+
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law.
+
+See the `COPYING` file for license details.  
+Part of `weasel-pageant` is derived from the PuTTY program, whose original license is
+in the file `COPYING.PuTTY`.

create_pkg.py

@@ -0,0 +1,55 @@
+#
+# weasel-pageant packaging script.
+# 
+# Copyright 2017  Valtteri Vuorikoski
+#
+# This file is part of weasel-pageant, and 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 3 of the License, or (at your option) any later version.
+#
+
+import sys
+import zipfile
+
+CURRENT_VERSION = '1.0'
+
+try:
+  reltype = sys.argv[1]
+except IndexError:
+  reltype = 'release'
+
+if reltype not in ('release', 'debug'):
+  print('usage: create_pkg release|debug', file=sys.stderr)
+  sys.exit(1)
+
+manifest = [
+  'COPYING',
+  'COPYING.PuTTY',
+  'README.md'
+]
+
+if reltype == 'release':
+  dirname = 'weasel-pageant-%s' % CURRENT_VERSION
+  manifest.extend([
+    'x64/Release/helper.exe',
+    'linux/bin/x64/Release/weasel-pageant'
+  ])
+else:
+  dirname = 'weasel-pageant-%s-%s' % (reltype, CURRENT_VERSION)
+  manifest.extend([
+    'x64/Debug/helper.exe',
+    'linux/bin/x64/Debug/weasel-pageant'
+  ])
+
+outname = dirname + '.zip'
+zipf = zipfile.ZipFile(outname, 'w', compression=zipfile.ZIP_DEFLATED)
+
+def basename(x):
+  return x.rsplit('/')[-1]
+
+for fname in manifest:
+  zipf.write(fname, '%s/%s' % (dirname, basename(fname)))
+
+zipf.close()
+sys.exit(0)

linux/common.h

@@ -0,0 +1,30 @@
+#pragma once
+
+/*
+* weasel-pageant Linux/Win32 common header.
+* Copyright 2017  Valtteri Vuorikoski
+* Based on ssh-pageant, copyright 2009,2014  Josh Stone
+*
+* This file is part of weasel-pageant, and 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 3 of the License, or (at your option) any later version.
+*/
+
+// This file may be included from both the Linux and the Win32 code.
+
+#define AGENT_MAX_MSGLEN  8192
+
+#define WSLP_CHILD_FLAG_DEBUG (1 << 0)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+	static inline uint32_t msglen(const void *p) {
+		return 4 + ntohl(*(const uint32_t *)p);
+	}
+
+#ifdef __cplusplus
+};
+#endif

linux/linux.vcxproj

@@ -69,13 +69,31 @@
     <RemoteCCompileToolExe>gcc</RemoteCCompileToolExe>
     <RemoteLdToolExe>gcc</RemoteLdToolExe>
     <IncludePath>$(IncludePath);$(ProjectDir)include\x86_64-linux-gnu;$(ProjectDir)include;$(ISenseIncludePath)</IncludePath>
+    <TargetName>weasel-pageant</TargetName>
+    <TargetExt />
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <IncludePath>$(IncludePath);$(ProjectDir)include\x86_64-linux-gnu;$(ProjectDir)include;$(ISenseIncludePath)</IncludePath>
+    <TargetName>weasel-pageant</TargetName>
+    <TargetExt />
   </PropertyGroup>
   <ItemGroup>
     <ClCompile Include="main.c" />
   </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="common.h" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="..\README.md" />
+  </ItemGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
     <ClCompile>
-      <PreprocessorDefinitions>_GNU_SOURCE=1;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>_GNU_SOURCE=1</PreprocessorDefinitions>
+    </ClCompile>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <ClCompile>
+      <PreprocessorDefinitions>_GNU_SOURCE=1</PreprocessorDefinitions>
     </ClCompile>
   </ItemDefinitionGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />