From patchwork Thu Apr 14 13:13:58 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: 562473 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 01FA6C35296 for ; Thu, 14 Apr 2022 13:39:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243466AbiDNNlr (ORCPT ); Thu, 14 Apr 2022 09:41:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60102 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344485AbiDNNcQ (ORCPT ); Thu, 14 Apr 2022 09:32:16 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5DD701838A; Thu, 14 Apr 2022 06:29:51 -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 dfw.source.kernel.org (Postfix) with ESMTPS id EE6FD60C14; Thu, 14 Apr 2022 13:29:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 05B23C385A5; Thu, 14 Apr 2022 13:29:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649942990; bh=FomcOLTOekwEIH+iOHyPbBhkepnkpoHru2AtF8wkD1Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Tm9MlVaYb22ArlHMgansHne5BCEHF2WLqeUz1F1hMCjOAD1UoIrmz97q7IF04otOh RVbZNF9JV66M2WaQmM7XWRmiaKK4S4GOeagbhM1KfN7PMsAV5Mo2i1ITyp+U3iUpUE k8kJDV1eVisVtqquM+stbJymVnek8Fk90/ZZtrXQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , =?utf-8?q?Michal_Koutn?= =?utf-8?q?=C3=BD?= , Tejun Heo , Ovidiu Panait Subject: [PATCH 4.19 335/338] selftests: cgroup: Test open-time cgroup namespace usage for migration checks Date: Thu, 14 Apr 2022 15:13:58 +0200 Message-Id: <20220414110848.427179082@linuxfoundation.org> X-Mailer: git-send-email 2.35.2 In-Reply-To: <20220414110838.883074566@linuxfoundation.org> References: <20220414110838.883074566@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 [OP: backport to v4.19: adjust context, add wait.h and fcntl.h includes] Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman --- tools/testing/selftests/cgroup/test_core.c | 99 +++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) --- a/tools/testing/selftests/cgroup/test_core.c +++ b/tools/testing/selftests/cgroup/test_core.c @@ -1,8 +1,13 @@ /* SPDX-License-Identifier: GPL-2.0 */ +#define _GNU_SOURCE #include +#include #include +#include #include +#include +#include #include #include @@ -421,6 +426,99 @@ 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); @@ -434,6 +532,7 @@ struct corecg_test { T(test_cgcore_invalid_domain), T(test_cgcore_populated), T(test_cgcore_lesser_euid_open), + T(test_cgcore_lesser_ns_open), }; #undef T