From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2D72EC433DF for ; Wed, 27 May 2020 11:19:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 14472207CB for ; Wed, 27 May 2020 11:19:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388160AbgE0LTI (ORCPT ); Wed, 27 May 2020 07:19:08 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:57006 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387619AbgE0LTI (ORCPT ); Wed, 27 May 2020 07:19:08 -0400 Received: from ip5f5af183.dynamic.kabel-deutschland.de ([95.90.241.131] helo=wittgenstein.fritz.box) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1jdu5R-0000AW-CA; Wed, 27 May 2020 11:19:05 +0000 From: Christian Brauner To: linux-kernel@vger.kernel.org, Kees Cook Cc: Andy Lutomirski , Tycho Andersen , Matt Denton , Sargun Dhillon , Jann Horn , Chris Palmer , Aleksa Sarai , Robert Sesek , Jeffrey Vander Stoep , Linux Containers , Christian Brauner Subject: [PATCH 2/2] tests: test seccomp filter notifications Date: Wed, 27 May 2020 13:19:02 +0200 Message-Id: <20200527111902.163213-2-christian.brauner@ubuntu.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200527111902.163213-1-christian.brauner@ubuntu.com> References: <20200527111902.163213-1-christian.brauner@ubuntu.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This verifies we're correctly notified when a seccomp filter becomes unused when a notifier is in use. Signed-off-by: Christian Brauner --- tools/testing/selftests/seccomp/seccomp_bpf.c | 137 ++++++++++++++++++ 1 file changed, 137 insertions(+) diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index c0aa46ce14f6..472b93b1c3d5 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -45,12 +45,14 @@ #include #include #include +#include #include #include #include #include "../kselftest_harness.h" +#include "../clone3/clone3_selftests.h" #ifndef PR_SET_PTRACER # define PR_SET_PTRACER 0x59616d61 @@ -3686,6 +3688,141 @@ TEST(user_notification_continue) } } +TEST(user_notification_filter_empty) +{ + pid_t pid; + long ret; + int status; + struct pollfd pollfd; + struct clone_args args = { + .flags = CLONE_FILES, + .exit_signal = SIGCHLD, + }; + + ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); + ASSERT_EQ(0, ret) { + TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); + } + + pid = sys_clone3(&args, sizeof(args)); + ASSERT_GE(pid, 0); + + if (pid == 0) { + int listener; + + listener = user_trap_syscall(__NR_mknod, SECCOMP_FILTER_FLAG_NEW_LISTENER); + if (listener < 0) + _exit(EXIT_FAILURE); + + if (dup2(listener, 200) != 200) + _exit(EXIT_FAILURE); + + close(listener); + + _exit(EXIT_SUCCESS); + } + + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); + + /* + * The seccomp filter has become unused so we should be notified once + * the kernel gets around to cleaning up task struct. + */ + pollfd.fd = 200; + pollfd.events = POLLHUP; + + EXPECT_GT(poll(&pollfd, 1, -1), 0); + EXPECT_GT((pollfd.revents & POLLHUP) ?: 0, 0); +} + +static void *do_thread(void *data) +{ + return NULL; +} + +TEST(user_notification_filter_empty_threaded) +{ + pid_t pid; + long ret; + int status; + struct pollfd pollfd; + struct clone_args args = { + .flags = CLONE_FILES, + .exit_signal = SIGCHLD, + }; + + ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); + ASSERT_EQ(0, ret) { + TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); + } + + pid = sys_clone3(&args, sizeof(args)); + ASSERT_GE(pid, 0); + + if (pid == 0) { + pid_t pid1, pid2; + int listener, status; + pthread_t thread; + + listener = user_trap_syscall(__NR_dup, SECCOMP_FILTER_FLAG_NEW_LISTENER); + if (listener < 0) + _exit(EXIT_FAILURE); + + if (dup2(listener, 200) != 200) + _exit(EXIT_FAILURE); + + close(listener); + + pid1 = fork(); + if (pid1 < 0) + _exit(EXIT_FAILURE); + + if (pid1 == 0) + _exit(EXIT_SUCCESS); + + pid2 = fork(); + if (pid2 < 0) + _exit(EXIT_FAILURE); + + if (pid2 == 0) + _exit(EXIT_SUCCESS); + + if (pthread_create(&thread, NULL, do_thread, NULL) || + pthread_join(thread, NULL)) + _exit(EXIT_FAILURE); + + if (pthread_create(&thread, NULL, do_thread, NULL) || + pthread_join(thread, NULL)) + _exit(EXIT_FAILURE); + + if (waitpid(pid1, &status, 0) != pid1 || !WIFEXITED(status) || + WEXITSTATUS(status)) + _exit(EXIT_FAILURE); + + if (waitpid(pid2, &status, 0) != pid2 || !WIFEXITED(status) || + WEXITSTATUS(status)) + _exit(EXIT_FAILURE); + + exit(EXIT_SUCCESS); + } + + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); + + /* + * The seccomp filter has become unused so we should be notified once + * the kernel gets around to cleaning up task struct. + */ + pollfd.fd = 200; + pollfd.events = POLLHUP; + + EXPECT_GT(poll(&pollfd, 1, -1), 0); + EXPECT_GT((pollfd.revents & POLLHUP) ?: 0, 0); +} + /* * TODO: * - add microbenchmarks -- 2.26.2