From patchwork Tue Apr 12 06:31:09 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 560580 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E93F5C43217 for ; Tue, 12 Apr 2022 07:19:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233754AbiDLHVx (ORCPT ); Tue, 12 Apr 2022 03:21:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57812 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351889AbiDLHND (ORCPT ); Tue, 12 Apr 2022 03:13:03 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 59F79114D; Mon, 11 Apr 2022 23:54:07 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id E3632B81B4E; Tue, 12 Apr 2022 06:54:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 46415C385A6; Tue, 12 Apr 2022 06:54:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649746444; bh=UG8E96NmWmyT1eR57RezFnkCYzgTjNbUM2DsOBIh/tU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U/F7PE9BIk28pi7Ptmi/Z9+ebvUMGVUHYae9JXcjV5YozWditT7HroxkEkZFWP+bp 8Hg5nCqGww1JTcKnprB83hlDTmISBuD9KaKL0mmLdBLLzeT9CoT6MYcZ7FV8F7lESU ExfK7pM9RwcVZKYqRVztVNjfi9Uaz7UXjr8eh1Ow= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?utf-8?q?Michal_Koutn=C3=BD?= , Tejun Heo , Ovidiu Panait Subject: [PATCH 5.15 266/277] selftests: cgroup: Test open-time cgroup namespace usage for migration checks Date: Tue, 12 Apr 2022 08:31:09 +0200 Message-Id: <20220412062949.741881644@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220412062942.022903016@linuxfoundation.org> References: <20220412062942.022903016@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Tejun Heo commit bf35a7879f1dfb0d050fe779168bcf25c7de66f5 upstream. When a task is writing to an fd opened by a different task, the perm check should use the cgroup namespace of the latter task. Add a test for it. Tested-by: Michal Koutný Signed-off-by: Tejun Heo Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman --- tools/testing/selftests/cgroup/test_core.c | 97 +++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+) --- a/tools/testing/selftests/cgroup/test_core.c +++ b/tools/testing/selftests/cgroup/test_core.c @@ -1,11 +1,14 @@ /* SPDX-License-Identifier: GPL-2.0 */ +#define _GNU_SOURCE #include +#include #include #include #include #include #include +#include #include #include #include @@ -741,6 +744,99 @@ cleanup: return ret; } +struct lesser_ns_open_thread_arg { + const char *path; + int fd; + int err; +}; + +static int lesser_ns_open_thread_fn(void *arg) +{ + struct lesser_ns_open_thread_arg *targ = arg; + + targ->fd = open(targ->path, O_RDWR); + targ->err = errno; + return 0; +} + +/* + * cgroup migration permission check should be performed based on the cgroup + * namespace at the time of open instead of write. + */ +static int test_cgcore_lesser_ns_open(const char *root) +{ + static char stack[65536]; + const uid_t test_euid = 65534; /* usually nobody, any !root is fine */ + int ret = KSFT_FAIL; + char *cg_test_a = NULL, *cg_test_b = NULL; + char *cg_test_a_procs = NULL, *cg_test_b_procs = NULL; + int cg_test_b_procs_fd = -1; + struct lesser_ns_open_thread_arg targ = { .fd = -1 }; + pid_t pid; + int status; + + cg_test_a = cg_name(root, "cg_test_a"); + cg_test_b = cg_name(root, "cg_test_b"); + + if (!cg_test_a || !cg_test_b) + goto cleanup; + + cg_test_a_procs = cg_name(cg_test_a, "cgroup.procs"); + cg_test_b_procs = cg_name(cg_test_b, "cgroup.procs"); + + if (!cg_test_a_procs || !cg_test_b_procs) + goto cleanup; + + if (cg_create(cg_test_a) || cg_create(cg_test_b)) + goto cleanup; + + if (cg_enter_current(cg_test_b)) + goto cleanup; + + if (chown(cg_test_a_procs, test_euid, -1) || + chown(cg_test_b_procs, test_euid, -1)) + goto cleanup; + + targ.path = cg_test_b_procs; + pid = clone(lesser_ns_open_thread_fn, stack + sizeof(stack), + CLONE_NEWCGROUP | CLONE_FILES | CLONE_VM | SIGCHLD, + &targ); + if (pid < 0) + goto cleanup; + + if (waitpid(pid, &status, 0) < 0) + goto cleanup; + + if (!WIFEXITED(status)) + goto cleanup; + + cg_test_b_procs_fd = targ.fd; + if (cg_test_b_procs_fd < 0) + goto cleanup; + + if (cg_enter_current(cg_test_a)) + goto cleanup; + + if ((status = write(cg_test_b_procs_fd, "0", 1)) >= 0 || errno != ENOENT) + goto cleanup; + + ret = KSFT_PASS; + +cleanup: + cg_enter_current(root); + if (cg_test_b_procs_fd >= 0) + close(cg_test_b_procs_fd); + if (cg_test_b) + cg_destroy(cg_test_b); + if (cg_test_a) + cg_destroy(cg_test_a); + free(cg_test_b_procs); + free(cg_test_a_procs); + free(cg_test_b); + free(cg_test_a); + return ret; +} + #define T(x) { x, #x } struct corecg_test { int (*fn)(const char *root); @@ -757,6 +853,7 @@ struct corecg_test { T(test_cgcore_thread_migration), T(test_cgcore_destroy), T(test_cgcore_lesser_euid_open), + T(test_cgcore_lesser_ns_open), }; #undef T