From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C708C34677C; Tue, 21 Oct 2025 11:46:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761047200; cv=none; b=nYFZzTpBjEgQMcybXT5PIjtg8PK/RArlnJgWI04+VobFq3Z6d7KuR6HYSkbQWdpuYi9bnxejWOrgUnpV4ginGjUjSQWerox25XE2ifwVkSdMB7U/ZFyAc/NxBJVVN4rMHAzeAB/HltpVKbQoR3D0AvU9G3C2v1nQQKF0RbbtKr0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761047200; c=relaxed/simple; bh=fdHj1hsijB+BXri97N5cswYO4dlb02Ygb6q9aUmDKdA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=WANbBim0GYXMkEReOMA9YjBTtgx/GVNQ9imunjYruMzcC/OEDCYvzBLYmx3e6q8x/2FPdaO12FQ0skYfoR22HDn2WG2FtySxlGkpleKqStJPp3FpHyDTIyVvYikoCGSRTcsdQZChYzfcE0UmaMucsIupd8rdA6ew3IhSq+XYBYM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oi19gwlJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oi19gwlJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A7E4CC4CEFD; Tue, 21 Oct 2025 11:46:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761047200; bh=fdHj1hsijB+BXri97N5cswYO4dlb02Ygb6q9aUmDKdA=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=oi19gwlJDUVhq5kUDd2QIp9gj8Ozagb2CCM0FG9NP6s6XVp2mk7P89DDN0eAWUBtc LjvB9vnrVgqud9FLgUISHHaU2rIUAJEiTwgBpnrpqlvooJbOotEim4VMSgFID9B8oj gaiCiGKswkoQ1VU01OjYSokTpG9NZzTetraQpfC6A8NpLfa/4pJgRc9z8p5g6ik/hi fWqVaYE7I38MjhI2aAvvZZ95ftK7khleYq0phGL0ZmqYC+PETek/NFLuUrLdWLl2h9 NeHsVOHdggxVjrSGP5UEpKHo8miN7qBob8e7NODs/c0/aWd8KUB12u1EcFfq13UUa1 3/P8cR5gMdMHA== From: Christian Brauner Date: Tue, 21 Oct 2025 13:43:38 +0200 Subject: [PATCH RFC DRAFT 32/50] selftests/namespaces: fourteenth active reference count tests Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20251021-work-namespace-nstree-listns-v1-32-ad44261a8a5b@kernel.org> References: <20251021-work-namespace-nstree-listns-v1-0-ad44261a8a5b@kernel.org> In-Reply-To: <20251021-work-namespace-nstree-listns-v1-0-ad44261a8a5b@kernel.org> To: linux-fsdevel@vger.kernel.org, Josef Bacik , Jeff Layton Cc: Jann Horn , Mike Yuan , =?utf-8?q?Zbigniew_J=C4=99drzejewski-Szmek?= , Lennart Poettering , Daan De Meyer , Aleksa Sarai , Amir Goldstein , Tejun Heo , Johannes Weiner , Thomas Gleixner , Alexander Viro , Jan Kara , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, bpf@vger.kernel.org, Eric Dumazet , Jakub Kicinski , netdev@vger.kernel.org, Arnd Bergmann , Christian Brauner X-Mailer: b4 0.15-dev-96507 X-Developer-Signature: v=1; a=openpgp-sha256; l=4527; i=brauner@kernel.org; h=from:subject:message-id; bh=fdHj1hsijB+BXri97N5cswYO4dlb02Ygb6q9aUmDKdA=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWR8L3zHnPpjlhT3rxaDCDvFE8fW83ydeO3TmYfMnGU+r 5Omnlzk21HKwiDGxSArpsji0G4SLrecp2KzUaYGzBxWJpAhDFycAjCRZAOG/yHO/lwv6o7PNvTm D3n7wiQpo3rZ3alBD+eq2KeI9XrkZTAyPDz9i9PNxqCLaYOW7b77z7hszvdIRSt1FgSztcmUFEZ yAgA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Test that user namespace as a child also propagates correctly. Create user_A -> user_B, verify when user_B is active that user_A is also active. This is different from non-user namespace children. Signed-off-by: Christian Brauner --- .../selftests/namespaces/ns_active_ref_test.c | 138 +++++++++++++++++++++ 1 file changed, 138 insertions(+) diff --git a/tools/testing/selftests/namespaces/ns_active_ref_test.c b/tools/testing/selftests/namespaces/ns_active_ref_test.c index 4c077223b05c..1eb4dc07e924 100644 --- a/tools/testing/selftests/namespaces/ns_active_ref_test.c +++ b/tools/testing/selftests/namespaces/ns_active_ref_test.c @@ -1914,4 +1914,142 @@ TEST(ns_parent_multiple_children_refcount) } } +/* + * Test that user namespace as a child also propagates correctly. + * Create user_A -> user_B, verify when user_B is active that user_A + * is also active. This is different from non-user namespace children. + */ +TEST(ns_userns_child_propagation) +{ + struct file_handle *ua_handle, *ub_handle; + int ret, pipefd[2]; + pid_t pid; + int status; + __u64 ua_id, ub_id; + char ua_buf[sizeof(*ua_handle) + MAX_HANDLE_SZ]; + char ub_buf[sizeof(*ub_handle) + MAX_HANDLE_SZ]; + + ASSERT_EQ(pipe(pipefd), 0); + pid = fork(); + ASSERT_GE(pid, 0); + + if (pid == 0) { + close(pipefd[0]); + + /* Create user_A */ + if (setup_userns() < 0) { + close(pipefd[1]); + exit(1); + } + + int ua_fd = open("/proc/self/ns/user", O_RDONLY); + if (ua_fd < 0) { + close(pipefd[1]); + exit(1); + } + if (ioctl(ua_fd, NS_GET_ID, &ua_id) < 0) { + close(ua_fd); + close(pipefd[1]); + exit(1); + } + close(ua_fd); + + /* Create user_B (child of user_A) */ + if (setup_userns() < 0) { + close(pipefd[1]); + exit(1); + } + + int ub_fd = open("/proc/self/ns/user", O_RDONLY); + if (ub_fd < 0) { + close(pipefd[1]); + exit(1); + } + if (ioctl(ub_fd, NS_GET_ID, &ub_id) < 0) { + close(ub_fd); + close(pipefd[1]); + exit(1); + } + close(ub_fd); + + /* Send both namespace IDs */ + write(pipefd[1], &ua_id, sizeof(ua_id)); + write(pipefd[1], &ub_id, sizeof(ub_id)); + close(pipefd[1]); + exit(0); + } + + close(pipefd[1]); + + /* Read both namespace IDs - fixed size, no parsing needed */ + ret = read(pipefd[0], &ua_id, sizeof(ua_id)); + if (ret != sizeof(ua_id)) { + close(pipefd[0]); + waitpid(pid, NULL, 0); + SKIP(return, "Failed to read user_A namespace ID"); + } + + ret = read(pipefd[0], &ub_id, sizeof(ub_id)); + close(pipefd[0]); + if (ret != sizeof(ub_id)) { + waitpid(pid, NULL, 0); + SKIP(return, "Failed to read user_B namespace ID"); + } + + /* Construct file handles from namespace IDs */ + ua_handle = (struct file_handle *)ua_buf; + ua_handle->handle_bytes = sizeof(struct nsfs_file_handle); + ua_handle->handle_type = FILEID_NSFS; + struct nsfs_file_handle *ua_fh = (struct nsfs_file_handle *)ua_handle->f_handle; + ua_fh->ns_id = ua_id; + ua_fh->ns_type = 0; + ua_fh->ns_inum = 0; + + ub_handle = (struct file_handle *)ub_buf; + ub_handle->handle_bytes = sizeof(struct nsfs_file_handle); + ub_handle->handle_type = FILEID_NSFS; + struct nsfs_file_handle *ub_fh = (struct nsfs_file_handle *)ub_handle->f_handle; + ub_fh->ns_id = ub_id; + ub_fh->ns_type = 0; + ub_fh->ns_inum = 0; + + /* Open user_B before child exits */ + int ub_fd = open_by_handle_at(FD_NSFS_ROOT, ub_handle, O_RDONLY); + if (ub_fd < 0) { + waitpid(pid, NULL, 0); + SKIP(return, "Failed to open user_B"); + } + + waitpid(pid, &status, 0); + ASSERT_TRUE(WIFEXITED(status)); + if (WEXITSTATUS(status) != 0) { + close(ub_fd); + SKIP(return, "Child failed"); + } + + /* With user_B active, user_A should also be active */ + TH_LOG("Testing user_A active when child user_B is active"); + int ua_fd = open_by_handle_at(FD_NSFS_ROOT, ua_handle, O_RDONLY); + ASSERT_GE(ua_fd, 0); + + /* Close user_B */ + TH_LOG("Closing user_B"); + close(ub_fd); + + /* user_A should remain active (we hold direct ref) */ + int ua_fd2 = open_by_handle_at(FD_NSFS_ROOT, ua_handle, O_RDONLY); + ASSERT_GE(ua_fd2, 0); + close(ua_fd2); + + /* Close user_A - should become inactive */ + TH_LOG("Closing user_A - should become inactive"); + close(ua_fd); + + ua_fd = open_by_handle_at(FD_NSFS_ROOT, ua_handle, O_RDONLY); + if (ua_fd >= 0) { + close(ua_fd); + TH_LOG("Warning: user_A still active"); + } +} + TEST_HARNESS_MAIN -- 2.47.3