From 78ef3b19d40aa6f63412ba961ab5c8bf0939237e Mon Sep 17 00:00:00 2001
From: Runxi Yu <me@runxiyu.org>
Date: Wed, 12 Feb 2025 17:08:27 +0800
Subject: ssh.go: Add anonymous SSH cloning

---
 ssh.go | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 ssh.go

(limited to 'ssh.go')

diff --git a/ssh.go b/ssh.go
new file mode 100644
index 0000000..e1b9ff1
--- /dev/null
+++ b/ssh.go
@@ -0,0 +1,82 @@
+package main
+
+import (
+	"fmt"
+	"net"
+	"os"
+	"os/exec"
+
+	glider_ssh "github.com/gliderlabs/ssh"
+	"go.lindenii.runxiyu.org/lindenii-common/clog"
+	go_ssh "golang.org/x/crypto/ssh"
+)
+
+func serve_ssh() error {
+	hostKeyBytes, err := os.ReadFile(config.SSH.Key)
+	if err != nil {
+		return err
+	}
+
+	hostKey, err := go_ssh.ParsePrivateKey(hostKeyBytes)
+	if err != nil {
+		return err
+	}
+
+	server := &glider_ssh.Server{
+		Handler: func(session glider_ssh.Session) {
+			client_public_key := session.PublicKey()
+			var client_public_key_string string
+			if client_public_key != nil {
+				client_public_key_string = string(go_ssh.MarshalAuthorizedKey(client_public_key))
+			}
+			_ = client_public_key_string
+
+			cmd := session.Command()
+
+			if len(cmd) < 2 {
+				fmt.Fprintln(session.Stderr(), "Insufficient arguments")
+				return
+			}
+
+			if cmd[0] != "git-upload-pack" {
+				fmt.Fprintln(session.Stderr(), "Unsupported command")
+				return
+			}
+
+			proc := exec.CommandContext(session.Context(), cmd[0], "/home/runxiyu/git/forge.git")
+			proc.Stdin = session
+			proc.Stdout = session
+			proc.Stderr = session.Stderr()
+
+			err := proc.Start()
+			if err != nil {
+				fmt.Fprintln(session.Stderr(), "Error while starting process:", err)
+				return
+			}
+			err = proc.Wait()
+			if exitError, ok := err.(*exec.ExitError); ok {
+				fmt.Fprintln(session.Stderr(), "Process exited with error", exitError.ExitCode())
+			} else if err != nil {
+				fmt.Fprintln(session.Stderr(), "Error while waiting for process:", err)
+			}
+		},
+		PublicKeyHandler:           func(ctx glider_ssh.Context, key glider_ssh.PublicKey) bool { return true },
+		KeyboardInteractiveHandler: func(ctx glider_ssh.Context, challenge go_ssh.KeyboardInteractiveChallenge) bool { return true },
+	}
+
+	server.AddHostKey(hostKey)
+
+	listener, err := net.Listen("tcp", ":2222")
+	if err != nil {
+		return err
+	}
+
+	go func() {
+		err = server.Serve(listener)
+		if err != nil {
+			clog.Fatal(1, "Serving SSH: "+err.Error())
+		}
+	}()
+
+	return nil
+}
-- 
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