| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20251022-work-namespace-nstree-listns-v2-46-71a588572371@kernel.org>
Date: Wed, 22 Oct 2025 18:06:24 +0200
From: Christian Brauner <brauner@...nel.org>
To: linux-fsdevel@...r.kernel.org, Josef Bacik <josef@...icpanda.com>,
Jeff Layton <jlayton@...nel.org>
Cc: Jann Horn <jannh@...gle.com>, Mike Yuan <me@...dnzj.com>,
Zbigniew Jędrzejewski-Szmek <zbyszek@...waw.pl>,
Lennart Poettering <mzxreary@...inter.de>,
Daan De Meyer <daan.j.demeyer@...il.com>, Aleksa Sarai <cyphar@...har.com>,
Amir Goldstein <amir73il@...il.com>, Tejun Heo <tj@...nel.org>,
Johannes Weiner <hannes@...xchg.org>, Thomas Gleixner <tglx@...utronix.de>,
Alexander Viro <viro@...iv.linux.org.uk>, Jan Kara <jack@...e.cz>,
linux-kernel@...r.kernel.org, cgroups@...r.kernel.org, bpf@...r.kernel.org,
Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
netdev@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
Christian Brauner <brauner@...nel.org>
Subject: [PATCH v2 46/63] selftests/namespaces: second listns() permission
test
Test that users with CAP_SYS_ADMIN in a user namespace can see
all namespaces owned by that user namespace.
Signed-off-by: Christian Brauner <brauner@...nel.org>
---
.../selftests/namespaces/listns_permissions_test.c | 103 +++++++++++++++++++++
1 file changed, 103 insertions(+)
diff --git a/tools/testing/selftests/namespaces/listns_permissions_test.c b/tools/testing/selftests/namespaces/listns_permissions_test.c
index 87ec71560d99..803c42fc76ec 100644
--- a/tools/testing/selftests/namespaces/listns_permissions_test.c
+++ b/tools/testing/selftests/namespaces/listns_permissions_test.c
@@ -131,4 +131,107 @@ TEST(listns_unprivileged_current_only)
unexpected_count);
}
+/*
+ * Test that users with CAP_SYS_ADMIN in a user namespace can see
+ * all namespaces owned by that user namespace.
+ */
+TEST(listns_cap_sys_admin_in_userns)
+{
+ struct ns_id_req req = {
+ .size = sizeof(req),
+ .spare = 0,
+ .ns_id = 0,
+ .ns_type = 0, /* All types */
+ .spare2 = 0,
+ .user_ns_id = 0, /* Will be set to our created user namespace */
+ };
+ __u64 ns_ids[100];
+ int pipefd[2];
+ pid_t pid;
+ int status;
+ bool success;
+ ssize_t count;
+
+ ASSERT_EQ(pipe(pipefd), 0);
+
+ pid = fork();
+ ASSERT_GE(pid, 0);
+
+ if (pid == 0) {
+ int fd;
+ __u64 userns_id;
+ ssize_t ret;
+ int min_expected;
+ bool success;
+
+ close(pipefd[0]);
+
+ /* Create user namespace - we'll have CAP_SYS_ADMIN in it */
+ if (setup_userns() < 0) {
+ close(pipefd[1]);
+ exit(1);
+ }
+
+ /* Get the user namespace ID */
+ fd = open("/proc/self/ns/user", O_RDONLY);
+ if (fd < 0) {
+ close(pipefd[1]);
+ exit(1);
+ }
+
+ if (ioctl(fd, NS_GET_ID, &userns_id) < 0) {
+ close(fd);
+ close(pipefd[1]);
+ exit(1);
+ }
+ close(fd);
+
+ /* Create several namespaces owned by this user namespace */
+ unshare(CLONE_NEWNET);
+ unshare(CLONE_NEWUTS);
+ unshare(CLONE_NEWIPC);
+
+ /* List namespaces owned by our user namespace */
+ req.user_ns_id = userns_id;
+ ret = sys_listns(&req, ns_ids, ARRAY_SIZE(ns_ids), 0);
+ if (ret < 0) {
+ close(pipefd[1]);
+ exit(1);
+ }
+
+ /*
+ * We have CAP_SYS_ADMIN in this user namespace,
+ * so we should see all namespaces owned by it.
+ * That includes: net, uts, ipc, and the user namespace itself.
+ */
+ min_expected = 4;
+ success = (ret >= min_expected);
+
+ write(pipefd[1], &success, sizeof(success));
+ write(pipefd[1], &ret, sizeof(ret));
+ close(pipefd[1]);
+ exit(0);
+ }
+
+ /* Parent */
+ close(pipefd[1]);
+
+ success = false;
+ count = 0;
+ read(pipefd[0], &success, sizeof(success));
+ read(pipefd[0], &count, sizeof(count));
+ close(pipefd[0]);
+
+ waitpid(pid, &status, 0);
+ ASSERT_TRUE(WIFEXITED(status));
+
+ if (WEXITSTATUS(status) != 0) {
+ SKIP(return, "Child failed to setup namespaces");
+ }
+
+ ASSERT_TRUE(success);
+ TH_LOG("User with CAP_SYS_ADMIN saw %zd namespaces owned by their user namespace",
+ count);
+}
+
TEST_HARNESS_MAIN
--
2.47.3
Powered by blists - more mailing lists