WIP

hosts/bekkalokk/services/gitea/default.nix

@@ -6,7 +6,8 @@ let
 in {
   imports = [
     ./ci.nix
-    ./import-users.nix
+    ./import-users
+    ./web-secret-provider
   ];
 
   sops.secrets = {

hosts/bekkalokk/services/gitea/web-secret-provider/default.nix

@@ -0,0 +1,100 @@
+{ config, pkgs, lib, ... }:
+let
+  sops.secrets = {
+    "gitea/web-secret-provider/Drift" = {
+      owner = "gitea";
+      group = "gitea";
+      restartUnits = [ "gitea-web-secret-provider@Drift" ];
+    };
+    "gitea/web-secret-provider/Projects" = {
+      owner = "gitea";
+      group = "gitea";
+      restartUnits = [ "gitea-web-secret-provider@Projects" ];
+    };
+    "gitea/web-secret-provider/Kurs" = {
+      owner = "gitea";
+      group = "gitea";
+      restartUnits = [ "gitea-web-secret-provider@Kurs" ];
+  };
+
+  cfg = config.services.gitea;
+
+  program = pkgs.writers.writePython3 "gitea-web-secret-provider" {
+    libraries = with pkgs.python3Packages; [ requests ];
+    makeWrapperArgs = [
+      "--prefix PATH : ${(lib.makeBinPath [ pkgs.openssh ])}"
+    ];
+  } (builtins.readFile ./gitea-web-secret-provider.py);
+in
+{
+
+  # https://www.freedesktop.org/software/systemd/man/latest/systemd.unit.html#Specifiers
+  # %i - instance name (after the @)
+  # %d - secrets directory
+  # %s - /var/lib
+  systemd.services = {
+    "gitea-web-secret-provider@" = {
+      description = "Gitea web secret provider";
+      wantedBy = [ "multi-user.target" ];
+      requires = [ "gitea.service" "network.target" ];
+      serviceConfig = {
+        Type = "oneshot";
+        ExecStart = let
+          args = lib.cli.toGNUCommandLineShell { } {
+            org = "%i";
+            token-path = "%d/token";
+            api-url = "${cfg.settings.server.ROOT_URL}api/v1";
+            key-dir = "%s/%i/keys";
+            authorized-keys-path = "%s/gitea-web/authorized_keys.d/%i";
+            rrsync-path = "${pkgs.rrsync}/bin/rrsync";
+            web-dir = "%s/gitea-web/web";
+          };
+        in "${program} ${args}";
+        User = "gitea";
+        Group = "gitea";
+        Restart = "always";
+
+        StateDir = "%i";
+        WorkingDirectory = "%s/%i";
+
+        # Hardening
+        NoNewPrivileges = true;
+        PrivateTmp = true;
+        PrivateDevices = true;
+        ProtectSystem = true;
+        ProtectHome = true;
+        ProtectControlGroups = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        RestrictAddressFamilies = [ "AF_INET" "AF_INET6" ];
+        RestrictRealtime = true;
+        RestrictSUIDSGID = true;
+        MemoryDenyWriteExecute = true;
+        LockPersonality = true;
+      };
+    };
+  }
+  //
+  builtins.listToAttrs (map (org: lib.nameValuePair "gitea-web-secret-provider@${org}" {
+      serviceConfig.LoadCredential = [
+        "token:${config.sops.secrets."gitea/web-secret-provider/${org}".path}"
+      ];
+  }));
+
+  systemd.timers = {
+    "gitea-web-secret-provider@" = {
+      description = "Run the Gitea web secret provider";
+      wantedBy = [ "timers.target" ];
+      timerConfig = {
+        OnCalendar = "daily";
+        RandomizedDelaySec = "1h";
+        Persistent = true;
+        Unit = "gitea-web-secret-provider@%i.service";
+      };
+    };
+  }
+  //
+  builtins.listToAttrs (map (org: lib.nameValuePair "gitea-web-secret-provider@${org}" { }));
+
+  # services.nginx.virtualHosts.
+}

hosts/bekkalokk/services/gitea/web-secret-provider/gitea-web-secret-provider.py

@@ -0,0 +1,105 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -i python3 -p "python3.withPackages(ps: with ps; [ requests ])" openssh
+
+import argparse
+import hashlib
+import os
+import requests
+import subprocess
+
+
+def parse_args():
+    parser = argparse.ArgumentParser(description="Generate SSH keys for Gitea repositories and add them as secrets")
+    parser.add_argument("--org", required=True, help="The organization to generate keys for")
+    parser.add_argument("--token-path", metavar='PATH', required=True, help="Path to a file containing the Gitea API token")
+    parser.add_argument("--api-url", metavar='URL', help="The URL of the Gitea API", default="https://git.pvv.ntnu.no/api/v1")
+    parser.add_argument("--key-dir", metavar='PATH', help="The directory to store the generated keys in", default="/run/gitea-web-secret-provider")
+    parser.add_argument("--authorized-keys-path", metavar='PATH', help="The path to the resulting authorized_keys file", default="/etc/ssh/authorized_keys.d/gitea-web-secret-provider")
+    parser.add_argument("--rrsync-path", metavar='PATH', help="The path to the rrsync binary", default="/run/current-system/sw/bin/rrsync")
+    parser.add_argument("--web-dir", metavar='PATH', help="The directory to sync the repositories to", default="/var/www")
+    parser.add_argument("--force", action="store_true", help="Overwrite existing keys")
+    return parser.parse_args()
+
+
+def add_secret(args, token, repo, name, secret):
+    result = requests.put(
+        f"{args.api_url}/repos/{args.org}/{repo}/actions/secrets/{name}",
+        json = { 'data': secret },
+        headers = { 'Authorization': 'token ' + token },
+    )
+    if result.status_code not in (201, 204):
+        raise Exception(f"Failed to add secret: {result.json()}")
+
+
+def get_org_repo_list(args, token):
+    result = requests.get(
+        f"{args.api_url}/orgs/{args.org}/repos",
+        headers = { 'Authorization': 'token ' + token },
+    )
+    return [repo["name"] for repo in result.json()]
+
+
+def generate_ssh_key(args, repository: str):
+    keyname = hashlib.sha256(args.org.encode() + repository.encode()).hexdigest()
+
+    if not os.path.exists(os.path.join(args.key_dir, keyname)) or args.force:
+        subprocess.run(
+            [
+                "ssh-keygen",
+                *("-t", "ed25519"),
+                *("-b", "4096"),
+                *("-f", os.path.join(args.key_dir, keyname)),
+                *("-N", ""),
+                *("-C", f"{args.org}/{repository}"),
+            ],
+            check=True,
+            stdin=subprocess.DEVNULL,
+            stdout=subprocess.DEVNULL,
+            stderr=subprocess.DEVNULL
+        )
+        print(f"Generated SSH key for `{args.org}/{repository}`")
+
+    with open(os.path.join(args.key_dir, keyname), "r") as f:
+        private_key = f.read()
+
+    with open(os.path.join(args.key_dir, keyname + ".pub"), "r") as f:
+        public_key = f.read()
+
+    return private_key, public_key
+
+
+def generate_authorized_keys(args, repo_public_keys: list[tuple[str, str]]):
+    result = ""
+    for repo, public_key in repo_public_keys:
+        result += f"""
+            command="{args.rrsync_path} -wo {args.web_dir}/{args.org}/{repo}",restrict,no-agent-forwarding,no-port-forwarding,no-pty,no-X11-forwarding {public_key}
+        """.strip() + "\n"
+
+    with open(args.authorized_keys_path, "w") as f:
+        f.write(result)
+
+
+def main():
+    args = parse_args()
+
+    with open(args.token_path, "r") as f:
+        token = f.read().strip()
+
+    os.makedirs(args.key_dir, 0o700, exist_ok=True)
+
+    repos = get_org_repo_list(args, token)
+    print(f'Found {len(repos)} repositories in `{args.org}`')
+
+    repo_public_keys = []
+    for repo in repos:
+        print(f"Locating key for `{args.org}/{repo}`")
+        private_key, public_key = generate_ssh_key(args, repo)
+        add_secret(args, token, repo, "WEB_SYNC_SSH_KEY", private_key)
+        repo_public_keys.append((repo, public_key))
+
+    generate_authorized_keys(args, repo_public_keys)
+    print(f"Wrote authorized_keys file to `{args.authorized_keys_path}`")
+
+
+if __name__ == "__main__":
+    main()