programs/workerbee: Mount VCS directories in readonly To prevent command execution on host, and other unwanted changes idk. The most vulnerable point here is git hooks. Protecting only ".git/hooks" is not enough as the attacker can modify "core.hooksPath" on repository config.

Changes

2 changed files (+77/-0)

• programs/workerbee/default.nix
  • @@ -81,6 +81,14 @@ stdenvNoCC.mkDerivation rec {
    --long project \ --require-parameter \ -d "Project directory to bind mount" + + complete -c ${name} \ + --condition "__fish_seen_subcommand_from incus; and __fish_seen_subcommand_from $incus_commands" \ + --long mutable \ + --require-parameter \ + -d "Directory types to disable readonly mode" \ + --no-files \ + -a "git\t'.git directory under PROJECT' jj\t'.jj directory under PROJECT'" EOF) ''; }
• programs/workerbee/src/incus_config.zig
  • @@ -36,6 +36,7 @@ const incus = struct {
    shift: bool = true, source: []const u8, path: []const u8, + readonly: bool = false, }; };
  • @@ -55,6 +56,12 @@ const Options = struct {
    /// Wayland socket to bind. wayland_socket: ?WaylandSocket = null, + /// Enable writes to "$PROJECT/.git". + mutable_git_dir: bool = false, + + /// Enable writes to "$PROJECT/.jj". + mutable_jj_dir: bool = false, + const WriteError = std.Io.Writer.Error || std.mem.Allocator.Error; fn writeJson(self: *const Options, allocator: std.mem.Allocator, writer: *std.Io.Writer) WriteError!void {
  • @@ -110,6 +117,24 @@ const Options = struct {
    .source = project_dir, .path = "/home/workerbee/project", }); + + if (!self.mutable_git_dir) { + try json.objectField("git"); + try json.write(incus.DiskDevice{ + .source = try std.fs.path.join(allocator, &.{ project_dir, ".git" }), + .path = "/home/workerbee/project/.git", + .readonly = true, + }); + } + + if (!self.mutable_jj_dir) { + try json.objectField("jj"); + try json.write(incus.DiskDevice{ + .source = try std.fs.path.join(allocator, &.{ project_dir, ".jj" }), + .path = "/home/workerbee/project/.jj", + .readonly = true, + }); + } } try json.endObject();
  • @@ -138,6 +163,15 @@ const help =
    \\ Project directory to bind mount. To use this option, \\ host and local machine MUST be the same. \\ + \\--mutable <VALUE>[,<VALUE>...] + \\ Comma-separated list of directories to disable readonly + \\ mount. To prevent unintentional command execution on + \\ container host, certain directories are mounted in + \\ readonly mode. You can allow writes certain directories + \\ using this option. Available values are: + \\ * git ... $PROJECT/.git + \\ * jj ... $PROJECT/.jj + \\ ; pub fn run(allocator: std.mem.Allocator, args: *std.process.ArgIterator) !exit.Code {
  • @@ -213,10 +247,45 @@ pub fn run(allocator: std.mem.Allocator, args: *std.process.ArgIterator) !exit.C
    continue; } + if (std.mem.eql(u8, arg, "--mutable")) { + const values = args.next() orelse { + std.log.err("{s} option requires a value", .{arg}); + return .incorrect_usage; + }; + + var values_iter = std.mem.splitScalar(u8, values, ','); + while (values_iter.next()) |value| { + if (std.mem.eql(u8, value, "git")) { + options.mutable_git_dir = true; + continue; + } + + if (std.mem.eql(u8, value, "jj")) { + options.mutable_jj_dir = true; + continue; + } + + std.log.err("Unknown value {s} at {s} option", .{ value, arg }); + return .incorrect_usage; + } + + continue; + } + std.log.err("Unknown option value: {s}", .{arg}); return .incorrect_usage; } + if (options.mutable_git_dir and options.project_dir == null) { + std.log.err("--mutable=git requires --project option", .{}); + return .incorrect_usage; + } + + if (options.mutable_jj_dir and options.project_dir == null) { + std.log.err("--mutable=jj requires --project option", .{}); + return .incorrect_usage; + } + var output_buffer: [1024]u8 = undefined; var output_writer = std.fs.File.stdout().writer(&output_buffer); const writer = &output_writer.interface;