bekkalokk/gitea: set up gitea-web sync units

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 +1,146 @@
+{ config, pkgs, lib, ... }:
+let
+  organizations = [
+    "Drift"
+    "Projects"
+    "Kurs"
+  ];
+
+  cfg = config.services.gitea;
+
+  program = pkgs.writers.writePython3 "gitea-web-secret-provider" {
+    libraries = with pkgs.python3Packages; [ requests ];
+    flakeIgnore = [
+      "E501" # Line over 80 chars lol
+      "E201" # "whitespace after {"
+      "E202" # "whitespace after }"
+      "E251" # unexpected spaces around keyword / parameter equals
+      "W391" # Newline at end of file
+    ];
+    makeWrapperArgs = [
+      "--prefix PATH : ${(lib.makeBinPath [ pkgs.openssh ])}"
+    ];
+  } (lib.pipe ./gitea-web-secret-provider.py [
+    builtins.readFile
+    (lib.splitString "\n")
+    (lib.drop 2)
+    lib.concatLines
+  ]);
+
+  commonHardening = {
+    NoNewPrivileges = true;
+    PrivateTmp = true;
+    PrivateDevices = true;
+    ProtectSystem = true;
+    ProtectHome = true;
+    ProtectControlGroups = true;
+    ProtectKernelModules = true;
+    ProtectKernelTunables = true;
+    RestrictAddressFamilies = [ "AF_INET" "AF_INET6" ];
+    RestrictRealtime = true;
+    RestrictSUIDSGID = true;
+    MemoryDenyWriteExecute = true;
+    LockPersonality = true;
+  };
+in
+{
+  sops.secrets."gitea/web-secret-provider/token" = {
+    owner = "gitea";
+    group = "gitea";
+    restartUnits = [
+      "gitea-web-secret-provider@"
+    ] ++ (map (org: "gitea-web-secret-provider@${org}") organizations);
+  };
+
+  systemd.tmpfiles.settings."10-gitea-web-secret-provider"."/var/lib/gitea-web/authorized_keys.d".d = {
+    user = "gitea";
+    group = "gitea";
+    mode = "700";
+  };
+
+  systemd.slices.system-giteaweb = {
+    description = "Gitea web directories";
+    wantedBy = [ "multi-user.target" ];
+  };
+
+  # 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 = "Ensure all repos in %i has an SSH key to push web content";
+      requires = [ "gitea.service" "network.target" ];
+      serviceConfig = {
+        Slice = "system-giteaweb.slice";
+        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} ${args}";
+        User = "gitea";
+        Group = "gitea";
+        StateDirectory = "%i";
+        LoadCredential = [
+          "token:${config.sops.secrets."gitea/web-secret-provider/token".path}"
+        ];
+      } // commonHardening;
+    };
+
+    "gitea-web-chown@" = {
+      description = "Ensure all gitea-web content is owned by the gitea user";
+      serviceConfig = {
+        Slice = "system-giteaweb.slice";
+        Type = "oneshot";
+        ExecStart = "${pkgs.coreutils}/bin/chown -R gitea:gitea '%S/gitea-web'";
+
+        StateDirectory = "%i";
+
+        LoadCredential = [
+          "token:${config.sops.secrets."gitea/web-secret-provider/token".path}"
+        ];
+
+        PrivateNetwork = true;
+      } // commonHardening;
+    };
+  };
+
+  systemd.timers = {
+    "gitea-web-secret-provider@" = {
+      description = "Ensure all repos in %i has an SSH key to push web content";
+      timerConfig = {
+        RandomizedDelaySec = "1h";
+        Persistent = true;
+        Unit = "gitea-web-secret-provider@%i.service";
+        OnCalendar = "daily";
+      };
+    };
+
+    "gitea-web-chown@" = {
+      description = "Ensure all gitea-web content is owned by the gitea user";
+      timerConfig = {
+        RandomizedDelaySec = "10m";
+        Persistent = true;
+        Unit = "gitea-web-chown@%i.service";
+        OnCalendar = "hourly";
+      };
+    };
+  };
+
+  systemd.targets.timers.wants = lib.mapCartesianProduct ({ timer, org }: "${timer}@${org}.timer") {
+    timer = [
+      "gitea-web-secret-provider"
+      "gitea-web-chown"
+    ];
+    org = organizations;
+  };
+
+  services.openssh.authorizedKeysFiles = map (org: "/var/lib/gitea-web/authorized_keys.d/${org}") organizations;
+}

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

@@ -0,0 +1,107 @@
+#!/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
+from pathlib import Path
+
+
+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)
+    os.makedirs(Path(args.authorized_keys_path).parent, 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()

secrets/bekkalokk/bekkalokk.yaml

@@ -1,4 +1,6 @@
 gitea:
+    web-secret-provider:
+        token: ENC[AES256_GCM,data:pHmBKxrNcLifl4sjR44AGEElfdachja35Tl/InsqvBWturaeTv4R0w==,iv:emBWfXQs2VNqtpDp5iA5swNC+24AWDYYXo6nvN+Fwx4=,tag:lkhSVSs6IqhHpfDPOX0wQA==,type:str]
     password: ENC[AES256_GCM,data:hlNzdU1ope0t50/3aztyLeXjMHd2vFPpwURX+Iu8f49DOqgSnEMtV+KtLA==,iv:qljRnSnchL5cFmaUAfCH9GQYQxcy5cyWejgk1x6bFgI=,tag:tIhboFU5kZsj5oAQR3hLbw==,type:str]
     database: ENC[AES256_GCM,data:UlS33IdCEyeSvT6ngpmnkBWHuSEqsB//DT+3b7C+UwbD8UXWJlsLf1X8/w==,iv:mPRW5ldyZaHP+y/0vC2JGSLZmlkhgmkvXPk4LazkSDs=,tag:gGk6Z/nbPvzE1zG+tJC8Sw==,type:str]
     email-password: ENC[AES256_GCM,data:KRwC+aL1aPvJuXt91Oq1ttATMnFTnuUy,iv:ats8TygB/2pORkaTZzPOLufZ9UmvVAKoRcWNvYF1z6w=,tag:Do0fA+4cZ3+l7JJyu8hjBg==,type:str]
@@ -90,8 +92,8 @@ sops:
             UHpLRkdQTnhkeGlWVG9VS1hkWktyckEKAdwnA9URLYZ50lMtXrU9Q09d0L3Zfsyr
             4UsvjjdnFtsXwEZ9ZzOQrpiN0Oz24s3csw5KckDni6kslaloJZsLGg==
             -----END AGE ENCRYPTED FILE-----
-    lastmodified: "2024-05-26T02:07:41Z"
-    mac: ENC[AES256_GCM,data:CRaJefV1zcJc6eyzyjTLgd0+Wv46VT8o4iz2YAGU+c2b/Cr97Tj290LoEO6UXTI3uFwVfzii2yZ2l+4FK3nVVriD4Cx1O/9qWcnLa5gfK30U0zof6AsJx8qtGu1t6oiPlGUCF7sT0BW9Wp8cPumrY6cZp9QbhmIDV0o0aJNUNN4=,iv:8OSYV1eG6kYlJD4ovZZhcD1GaYnmy7vHPa/+7egM1nE=,tag:OPI13rpDh2l1ViFj8TBFWg==,type:str]
+    lastmodified: "2024-08-13T19:49:24Z"
+    mac: ENC[AES256_GCM,data:AeJ53D+8A8mHYRmVHdqhcS1ZTbqVe5gQqJsJjMk4T/ZlNX8/V4M9mqAW2FB9m/JSdj234gDu+PBHcW70ZrCqeVsoUW/ETVgUX3W2gBmBgYJiRETp8I7/eks/5YEV6vIIxQsZNP/9dZTNX4T2wD74ELl23NSTXA/6k2tyzBlTMYo=,iv:DABafHvw+5w0PHCKqLgpwmQnv0uHOTyj+s8gdnHFTZ4=,tag:SNZ7W+6zdyuuv2AB9ir8eg==,type:str]
     pgp:
         - created_at: "2024-08-04T00:03:28Z"
           enc: |-
@@ -114,4 +116,4 @@ sops:
             -----END PGP MESSAGE-----
           fp: F7D37890228A907440E1FD4846B9228E814A2AAC
     unencrypted_suffix: _unencrypted
-    version: 3.8.1
+    version: 3.9.0