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 4017A329391; Wed, 29 Oct 2025 12:25:22 +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=1761740722; cv=none; b=JCV2O2lC+BRfIQdjzQf2EAhBphltzoCgLaBvyXAiNmV3RYTc4jc0Old4NUvR/uVzSI5V53XxTJUWgVx2x8Nl03RNYrjXbXh7c+qNAiXY9QEZaGEPDSrOFMtESGnBt27EqcVYdS7f0cxesAQIzMTnrHs3QOGxlozLch21UegjuMc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761740722; c=relaxed/simple; bh=M5JYL/ItXnif2Vw7+GSIT6vFRcZ0KyLdqVkykps56SU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=KEWBdAXAhwS8GTQHATO3V+ABmgWZmXndotZVel6aBAXduTswGmor7e7jq6kts9kzSZ+eMwFy5HvH6EsrxyqEur3kA3ycowb24gYt9bd396qsqUM7U+mL6c1g7MXg0qMR/jEvlBecQnkqIUHLyHskWn+ANTagel2/NnBulKQaE5w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QJ42iSYi; 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="QJ42iSYi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 94822C4CEFD; Wed, 29 Oct 2025 12:25:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761740722; bh=M5JYL/ItXnif2Vw7+GSIT6vFRcZ0KyLdqVkykps56SU=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=QJ42iSYiEc0/SyvSVlMLEFslZsDmPFkoufbTXhoF8eA1/9D3aerbubBsP7uwRRQTj ijj4DpmiN1CrJs58YtxNOexc9bBbTbEUOWoXLREV3paCtBOtfU8VsfRKB0yCLW+Hlm ZJ2XEorkEUzezWDkqDi5J4WK+IsdWxWfJWD9pJzP39I+BMb1aHRh4H+VZUuy7yr+62 /XJoyPpMMtLtmekHz2DBC8NQjvzoao0P7juPfC9BbzSfoBvfkSm0u4WhSffniub+1L 0drIWd5BM7rBQYxNxYjE6tCpo1gyKeD1Adki6AY2cGzEYJq8rxjTSfRY9ZPuLTTeZ2 us23UfdlMp5kg== From: Christian Brauner Date: Wed, 29 Oct 2025 13:21:09 +0100 Subject: [PATCH v4 56/72] selftests/namespaces: second inactive namespace resurrection test Precedence: bulk X-Mailing-List: linux-fsdevel@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: <20251029-work-namespace-nstree-listns-v4-56-2e6f823ebdc0@kernel.org> References: <20251029-work-namespace-nstree-listns-v4-0-2e6f823ebdc0@kernel.org> In-Reply-To: <20251029-work-namespace-nstree-listns-v4-0-2e6f823ebdc0@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=4149; i=brauner@kernel.org; h=from:subject:message-id; bh=M5JYL/ItXnif2Vw7+GSIT6vFRcZ0KyLdqVkykps56SU=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWQysfUbrJ9/6Vgc76cNQlJ1u7707VtZsk97wYKImLCiF d56/5zYO0pZGMS4GGTFFFkc2k3C5ZbzVGw2ytSAmcPKBDKEgYtTACZyUIuR4cCMs8nh2nov4u78 EtqVHFjQ+3H6761crjE9+5qPL4oM38zIsP5/wvqSpG97G63clD/fk/vrdu1zxHRuhyDLz96hUg+ 42AA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Test that socket file descriptors keep network namespaces active. Create a network namespace, create a socket in it, then exit the namespace. The namespace should remain active while the socket FD is held. Signed-off-by: Christian Brauner --- .../testing/selftests/namespaces/siocgskns_test.c | 126 +++++++++++++++++++++ 1 file changed, 126 insertions(+) diff --git a/tools/testing/selftests/namespaces/siocgskns_test.c b/tools/testing/selftests/namespaces/siocgskns_test.c index 0c9098624cd4..0ad5e39b7e16 100644 --- a/tools/testing/selftests/namespaces/siocgskns_test.c +++ b/tools/testing/selftests/namespaces/siocgskns_test.c @@ -69,4 +69,130 @@ TEST(siocgskns_basic) close(current_netns_fd); } +/* + * Test that socket file descriptors keep network namespaces active. + * Create a network namespace, create a socket in it, then exit the namespace. + * The namespace should remain active while the socket FD is held. + */ +TEST(siocgskns_keeps_netns_active) +{ + int sock_fd, netns_fd, test_fd; + int ipc_sockets[2]; + pid_t pid; + int status; + struct stat st; + + EXPECT_EQ(socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets), 0); + + pid = fork(); + ASSERT_GE(pid, 0); + + if (pid == 0) { + /* Child: create new netns and socket */ + close(ipc_sockets[0]); + + if (unshare(CLONE_NEWNET) < 0) { + TH_LOG("unshare(CLONE_NEWNET) failed: %s", strerror(errno)); + close(ipc_sockets[1]); + exit(1); + } + + /* Create a socket in the new network namespace */ + sock_fd = socket(AF_INET, SOCK_DGRAM, 0); + if (sock_fd < 0) { + TH_LOG("socket() failed: %s", strerror(errno)); + close(ipc_sockets[1]); + exit(1); + } + + /* Send socket FD to parent via SCM_RIGHTS */ + struct msghdr msg = {0}; + struct iovec iov = {0}; + char buf[1] = {'X'}; + char cmsg_buf[CMSG_SPACE(sizeof(int))]; + + iov.iov_base = buf; + iov.iov_len = 1; + msg.msg_iov = &iov; + msg.msg_iovlen = 1; + msg.msg_control = cmsg_buf; + msg.msg_controllen = sizeof(cmsg_buf); + + struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg); + cmsg->cmsg_level = SOL_SOCKET; + cmsg->cmsg_type = SCM_RIGHTS; + cmsg->cmsg_len = CMSG_LEN(sizeof(int)); + memcpy(CMSG_DATA(cmsg), &sock_fd, sizeof(int)); + + if (sendmsg(ipc_sockets[1], &msg, 0) < 0) { + close(sock_fd); + close(ipc_sockets[1]); + exit(1); + } + + close(sock_fd); + close(ipc_sockets[1]); + exit(0); + } + + /* Parent: receive socket FD */ + close(ipc_sockets[1]); + + struct msghdr msg = {0}; + struct iovec iov = {0}; + char buf[1]; + char cmsg_buf[CMSG_SPACE(sizeof(int))]; + + iov.iov_base = buf; + iov.iov_len = 1; + msg.msg_iov = &iov; + msg.msg_iovlen = 1; + msg.msg_control = cmsg_buf; + msg.msg_controllen = sizeof(cmsg_buf); + + ssize_t n = recvmsg(ipc_sockets[0], &msg, 0); + close(ipc_sockets[0]); + ASSERT_EQ(n, 1); + + struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg); + ASSERT_NE(cmsg, NULL); + ASSERT_EQ(cmsg->cmsg_type, SCM_RIGHTS); + + memcpy(&sock_fd, CMSG_DATA(cmsg), sizeof(int)); + + /* Wait for child to exit */ + waitpid(pid, &status, 0); + ASSERT_TRUE(WIFEXITED(status)); + if (WEXITSTATUS(status) != 0) + SKIP(close(sock_fd); return, "Child failed to create namespace"); + + /* Get network namespace from socket */ + netns_fd = ioctl(sock_fd, SIOCGSKNS); + if (netns_fd < 0) { + close(sock_fd); + if (errno == ENOTTY || errno == EINVAL) + SKIP(return, "SIOCGSKNS not supported"); + ASSERT_GE(netns_fd, 0); + } + + ASSERT_EQ(fstat(netns_fd, &st), 0); + + /* + * Namespace should still be active because socket FD keeps it alive. + * Try to access it via /proc/self/fd/. + */ + char path[64]; + snprintf(path, sizeof(path), "/proc/self/fd/%d", netns_fd); + test_fd = open(path, O_RDONLY); + ASSERT_GE(test_fd, 0); + close(test_fd); + close(netns_fd); + + /* Close socket - namespace should become inactive */ + close(sock_fd); + + /* Try SIOCGSKNS again - should fail since socket is closed */ + ASSERT_LT(ioctl(sock_fd, SIOCGSKNS), 0); +} + TEST_HARNESS_MAIN -- 2.47.3