From patchwork Sun Apr 17 21:04:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Ludovic_Court=C3=A8s?= X-Patchwork-Id: 38636 Return-Path: X-Original-To: patchwork@mira.cbaines.net Delivered-To: patchwork@mira.cbaines.net Received: by mira.cbaines.net (Postfix, from userid 113) id 229C427BBE9; Sun, 17 Apr 2022 22:06:24 +0100 (BST) X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on mira.cbaines.net X-Spam-Level: X-Spam-Status: No, score=-2.7 required=5.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,MAILING_LIST_MULTI,SPF_HELO_PASS autolearn=unavailable autolearn_force=no version=3.4.6 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mira.cbaines.net (Postfix) with ESMTPS id 7A76327BBE9 for ; Sun, 17 Apr 2022 22:06:23 +0100 (BST) Received: from localhost ([::1]:39122 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ngC6A-0006si-M5 for patchwork@mira.cbaines.net; Sun, 17 Apr 2022 17:06:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:32874) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ngC5r-0006Fu-Lq for guix-patches@gnu.org; Sun, 17 Apr 2022 17:06:03 -0400 Received: from debbugs.gnu.org ([209.51.188.43]:43545) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1ngC5r-0000Xq-CT for guix-patches@gnu.org; Sun, 17 Apr 2022 17:06:03 -0400 Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1ngC5r-000269-6o for guix-patches@gnu.org; Sun, 17 Apr 2022 17:06:03 -0400 X-Loop: help-debbugs@gnu.org Subject: [bug#54997] [PATCH 04/12] Add (guix least-authority). Resent-From: Ludovic =?utf-8?q?Court=C3=A8s?= Original-Sender: "Debbugs-submit" Resent-CC: guix-patches@gnu.org Resent-Date: Sun, 17 Apr 2022 21:06:03 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 54997 X-GNU-PR-Package: guix-patches X-GNU-PR-Keywords: patch To: 54997@debbugs.gnu.org Cc: Ludovic =?utf-8?q?Court=C3=A8s?= Received: via spool by 54997-submit@debbugs.gnu.org id=B54997.16502295517956 (code B ref 54997); Sun, 17 Apr 2022 21:06:03 +0000 Received: (at 54997) by debbugs.gnu.org; 17 Apr 2022 21:05:51 +0000 Received: from localhost ([127.0.0.1]:37420 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ngC5e-00024A-TD for submit@debbugs.gnu.org; Sun, 17 Apr 2022 17:05:51 -0400 Received: from eggs.gnu.org ([209.51.188.92]:39446) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ngC5Y-00022R-S4 for 54997@debbugs.gnu.org; Sun, 17 Apr 2022 17:05:45 -0400 Received: from fencepost.gnu.org ([2001:470:142:3::e]:58432) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ngC5T-0000VY-N8; Sun, 17 Apr 2022 17:05:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=MIME-Version:References:In-Reply-To:Date:Subject:To: From; bh=d6/DPBbhkS1XwGbod43NES4lGvcR+/kUYIR+TVHhgW0=; b=RsDYF7s8GZ8jX+t7Wxnq WerDTerkqnvXcdbM2aXruSKHNDNeorIlQYa7t1q+KXzDA3HncgpWTVdN+IDKxoFBkLb3309DgiagG /RfnDFGrYaIfoq5qXog86XMdooeEqPi00VNalUCNOSk3uhb+SwAY3uUl7Qmu9De6MZigmdnRdU5SM 3KisbyxjcQfyNlsxl7VJYrDP82SjkocOCNIzA9N8xAcH9V677acDvS53idAJTEjs/YZQftnrL/G0f ESlAG5d/CLnlMSP3aTMxzlKTekoRmVILUOoWVf2mmT/QX14cv+S9Ntk/CWUq7PAVqzvrBUUxTI+2u mykJAiA6aGPlPg==; Received: from [2a01:e0a:1d:7270:af76:b9b:ca24:c465] (port=38870 helo=gnu.org) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1ngC5T-000268-AS; Sun, 17 Apr 2022 17:05:39 -0400 From: Ludovic =?utf-8?q?Court=C3=A8s?= Date: Sun, 17 Apr 2022 23:04:45 +0200 Message-Id: <20220417210453.27884-4-ludo@gnu.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220417210453.27884-1-ludo@gnu.org> References: <20220417210453.27884-1-ludo@gnu.org> MIME-Version: 1.0 X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: guix-patches@gnu.org List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-patches-bounces+patchwork=mira.cbaines.net@gnu.org Sender: "Guix-patches" X-getmail-retrieved-from-mailbox: Patches * guix/least-authority.scm: New file. * Makefile.am (MODULES): Add it. * gnu/build/shepherd.scm (default-mounts): Make public. --- Makefile.am | 1 + gnu/build/shepherd.scm | 3 +- guix/least-authority.scm | 131 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 134 insertions(+), 1 deletion(-) create mode 100644 guix/least-authority.scm diff --git a/Makefile.am b/Makefile.am index fecce7c6f7..d0d58da4e3 100644 --- a/Makefile.am +++ b/Makefile.am @@ -130,6 +130,7 @@ MODULES = \ guix/cache.scm \ guix/cve.scm \ guix/workers.scm \ + guix/least-authority.scm \ guix/ipfs.scm \ guix/build-system.scm \ guix/build-system/android-ndk.scm \ diff --git a/gnu/build/shepherd.scm b/gnu/build/shepherd.scm index d52e53eb78..f4caefce3c 100644 --- a/gnu/build/shepherd.scm +++ b/gnu/build/shepherd.scm @@ -31,7 +31,8 @@ (define-module (gnu build shepherd) exec-command %precious-signals) #:autoload (shepherd system) (unblock-signals) - #:export (make-forkexec-constructor/container + #:export (default-mounts + make-forkexec-constructor/container fork+exec-command/container)) ;;; Commentary: diff --git a/guix/least-authority.scm b/guix/least-authority.scm new file mode 100644 index 0000000000..806c47508f --- /dev/null +++ b/guix/least-authority.scm @@ -0,0 +1,131 @@ +;;; GNU Guix --- Functional package management for GNU +;;; Copyright © 2022 Ludovic Courtès +;;; +;;; This file is part of GNU Guix. +;;; +;;; GNU Guix is free software; you can redistribute it and/or modify it +;;; under the terms of the GNU General Public License as published by +;;; the Free Software Foundation; either version 3 of the License, or (at +;;; your option) any later version. +;;; +;;; GNU Guix is distributed in the hope that it will be useful, but +;;; WITHOUT ANY WARRANTY; without even the implied warranty of +;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +;;; GNU General Public License for more details. +;;; +;;; You should have received a copy of the GNU General Public License +;;; along with GNU Guix. If not, see . + +(define-module (guix least-authority) + #:use-module (guix gexp) + #:use-module (guix modules) + #:use-module ((guix store) #:select (%store-prefix)) + #:autoload (gnu build linux-container) (%namespaces) + #:autoload (gnu system file-systems) (file-system-mapping + file-system-mapping-source + spec->file-system + file-system->spec + file-system-mapping->bind-mount) + #:export (least-authority-wrapper)) + +;;; Commentary: +;;; +;;; This module provides tools to execute programs with the least authority +;;; necessary, using Linux namespaces. +;;; +;;; Code: + +(define %precious-variables + ;; Environment variables preserved by the wrapper by default. + '("HOME" "USER" "LOGNAME" "DISPLAY" "XAUTHORITY" "TERM" "TZ" "PAGER")) + +(define* (least-authority-wrapper program + #:key (name "pola-wrapper") + (guest-uid 1000) + (guest-gid 1000) + (mappings '()) + (namespaces %namespaces) + (directory "/") + (preserved-environment-variables + %precious-variables)) + "Return a wrapper of PROGRAM that executes it with the least authority. + +PROGRAM is executed in separate namespaces according to NAMESPACES, a list of +symbols; it turns with GUEST-UID and GUEST-GID. MAPPINGS is a list of + records indicating directories mirrored inside the +execution environment of PROGRAM. DIRECTORY is the working directory of the +wrapped process. Each environment listed in PRESERVED-ENVIRONMENT-VARIABLES +is preserved; other environment variables are erased." + (define code + (with-imported-modules (source-module-closure + '((gnu system file-systems) + (gnu build shepherd) + (gnu build linux-container))) + #~(begin + (use-modules (gnu system file-systems) + (gnu build linux-container) + ((gnu build shepherd) #:select (default-mounts)) + (srfi srfi-1)) + + (define variables + (filter-map (lambda (variable) + (let ((value (getenv variable))) + (and value + (string-append variable "=" value)))) + '#$preserved-environment-variables)) + + (define (read-file file) + (call-with-input-file file read)) + + (define references + (delete-duplicates + (append-map read-file + '#$(map references-file + (cons program + (map file-system-mapping-source + mappings)))))) + + (define (store? file-system) + (string=? (file-system-mount-point file-system) + #$(%store-prefix))) + + (define mounts + (append (map (lambda (item) + (file-system-mapping->bind-mount + (file-system-mapping (source item) + (target item)))) + references) + (remove store? + (default-mounts + #:namespaces '#$namespaces)) + (map spec->file-system + '#$(map (compose file-system->spec + file-system-mapping->bind-mount) + mappings)))) + + (define (reify-exit-status status) + (cond ((status:exit-val status) => exit) + ((or (status:term-sig status) + (status:stop-sig status)) + => (lambda (signal) + (format (current-error-port) + "~a terminated with signal ~a~%" + #$program signal) + (exit 126))))) + + ;; Note: 'call-with-container' creates a sub-process that this one + ;; waits for. This might seem suboptimal but unshare(2) isn't + ;; really applicable: the process would still run in the same PID + ;; namespace. + + (reify-exit-status + (call-with-container mounts + (lambda () + (chdir #$directory) + (environ variables) + (apply execl #$program #$program (cdr (command-line)))) + #:guest-uid #$guest-uid + #:guest-gid #$guest-gid + #:namespaces '#$namespaces))))) + + (program-file name code))