initial commit

Author: progrium

.gitignore

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+execd

LICENSE

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+Copyright (C) 2014 Jeff Lindsay
+
+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 AUTHORS OR 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.

Makefile

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+
+build:
+	go build .

README.md

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+# execd
+
+A very lightweight SSH server frontend written in Go. The backend auth and execution logic is handled by commands you specify, letting you customize its behavior via your own scripts/executables.
+
+## Using execd
+```
+Usage: ./execd [options] <auth-handler> <exec-handler>
+
+  -d=false: debug mode displays handler output
+  -e=false: pass environment to handlers
+  -k="": pem file of private keys (read from SSH_PRIVATE_KEYS by default)
+  -p="22": port to listen on
+  -s=false: run exec handler via SHELL
+```
+#### auth-handler $user $key
+
+ * `$user` argument is the name of the user being used to attempt the connection
+ * `$key` argument is the public key data being provided for authentication
+
+auth-handler is the path to an executable that's used for authenticating incoming SSH connections. If it returns with exit status 0, the connection will be allowed, otherwise it will be denied. The output of auth-handler must be empty, or key-value pairs in the form `KEY=value` separated by newlines, which will be added to the environment of exec-handler.
+
+Although auth-handler is required, you can still achieve no-auth open access by providing `/usr/bin/true` as auth-handler.
+
+#### exec-handler $command...
+
+ * `$command...` arguments is the command line that was specified to run by the SSH client
+
+exec-handler is the path to an executable that's used to execute the command provided by the client. The meaning of that is quite flexible. All of the stdout and stderr is returned to the client, including the exit status. If the client provides stdin, that's passed to the exec-handler. Any environment variables provided by the auth-handler output will be available to exec-handler, as well as `$USER` and `$SSH_ORIGINAL_COMMAND` environment variables.
+
+## Credit / History
+
+It started with [gitreceive](https://github.com/progrium/gitreceive), which was then used in [Dokku](https://github.com/progrium/dokku). Then I made a more generalized version of gitreceive, more similar to execd, called [sshcommand](https://github.com/progrium/sshcommand), which eventually replaced gitreceive in Dokku. When I started work on Flynn, the first projects included [gitreceived](https://github.com/flynn/gitreceived) (a standalone daemon version of gitreceive). This was refined by the Flynn community, namely Jonathan Rudenberg. 
+
+Eventually I came to realize gitreceived could be generalized / simplified further in a way that could be used *with* the original gitreceive, *and* replace sshcommand, *and* be used in Dokku, *and* potentially replace gitreceived in Flynn. This project takes learnings from all those projects, though mostly gitreceived.
+
+## Sponsors
+
+This project was made possible thanks to [DigitalOcean](http://digitalocean.com).
+
+## License
+
+BSD

SPONSORS

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+DigitalOcean 	http://digitalocean.com

example/authcheck

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+#!/bin/bash
+
+USER="$1"
+KEY="$2"
+
+generate_fingerprint() {
+  awk '{print $2}' | base64 -d | md5sum | awk '{print $1}' | sed -e 's/../:&/2g'
+}
+
+echo "USER=$USER"
+echo "FINGERPRINT=$(echo "$KEY" | generate_fingerprint)"
+
+grep "$KEY" "/home/$USER/.ssh/authorized_keys" > /dev/null 2>&1

example/helloworld

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+#!/bin/bash
+echo "Hello world"
+read hello
+echo "OK: $hello"

example/host_pk.pem

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+-----BEGIN DSA PRIVATE KEY-----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+-----END DSA PRIVATE KEY-----

example/id_dsa

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+-----BEGIN DSA PRIVATE KEY-----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+-----END DSA PRIVATE KEY-----

example/id_dsa.pub

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+ssh-dss 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 [email protected]