1 files changed, 559 insertions, 0 deletions

diff --git a/tools/testing/selftests/pidfd/pidfd_setns_test.c b/tools/testing/selftests/pidfd/pidfd_setns_test.c
new file mode 100644
index 000000000..6e2f2cd40
--- /dev/null
+++ b/tools/testing/selftests/pidfd/pidfd_setns_test.c
@@ -0,0 +1,559 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <linux/types.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syscall.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+
+#include "pidfd.h"
+#include "../clone3/clone3_selftests.h"
+#include "../kselftest_harness.h"
+
+enum {
+	PIDFD_NS_USER,
+	PIDFD_NS_MNT,
+	PIDFD_NS_PID,
+	PIDFD_NS_UTS,
+	PIDFD_NS_IPC,
+	PIDFD_NS_NET,
+	PIDFD_NS_CGROUP,
+	PIDFD_NS_PIDCLD,
+	PIDFD_NS_TIME,
+	PIDFD_NS_MAX
+};
+
+const struct ns_info {
+	const char *name;
+	int flag;
+} ns_info[] = {
+	[PIDFD_NS_USER]   = { "user",             CLONE_NEWUSER,   },
+	[PIDFD_NS_MNT]    = { "mnt",              CLONE_NEWNS,     },
+	[PIDFD_NS_PID]    = { "pid",              CLONE_NEWPID,    },
+	[PIDFD_NS_UTS]    = { "uts",              CLONE_NEWUTS,    },
+	[PIDFD_NS_IPC]    = { "ipc",              CLONE_NEWIPC,    },
+	[PIDFD_NS_NET]    = { "net",              CLONE_NEWNET,    },
+	[PIDFD_NS_CGROUP] = { "cgroup",           CLONE_NEWCGROUP, },
+	[PIDFD_NS_PIDCLD] = { "pid_for_children", 0,               },
+	[PIDFD_NS_TIME]	  = { "time",             CLONE_NEWTIME,   },
+};
+
+FIXTURE(current_nsset)
+{
+	pid_t pid;
+	int pidfd;
+	int nsfds[PIDFD_NS_MAX];
+
+	pid_t child_pid_exited;
+	int child_pidfd_exited;
+
+	pid_t child_pid1;
+	int child_pidfd1;
+	int child_nsfds1[PIDFD_NS_MAX];
+
+	pid_t child_pid2;
+	int child_pidfd2;
+	int child_nsfds2[PIDFD_NS_MAX];
+};
+
+static int sys_waitid(int which, pid_t pid, int options)
+{
+	return syscall(__NR_waitid, which, pid, NULL, options, NULL);
+}
+
+pid_t create_child(int *pidfd, unsigned flags)
+{
+	struct __clone_args args = {
+		.flags		= CLONE_PIDFD | flags,
+		.exit_signal	= SIGCHLD,
+		.pidfd		= ptr_to_u64(pidfd),
+	};
+
+	return sys_clone3(&args, sizeof(struct clone_args));
+}
+
+static bool switch_timens(void)
+{
+	int fd, ret;
+
+	if (unshare(CLONE_NEWTIME))
+		return false;
+
+	fd = open("/proc/self/ns/time_for_children", O_RDONLY | O_CLOEXEC);
+	if (fd < 0)
+		return false;
+
+	ret = setns(fd, CLONE_NEWTIME);
+	close(fd);
+	return ret == 0;
+}
+
+static ssize_t read_nointr(int fd, void *buf, size_t count)
+{
+	ssize_t ret;
+
+	do {
+		ret = read(fd, buf, count);
+	} while (ret < 0 && errno == EINTR);
+
+	return ret;
+}
+
+static ssize_t write_nointr(int fd, const void *buf, size_t count)
+{
+	ssize_t ret;
+
+	do {
+		ret = write(fd, buf, count);
+	} while (ret < 0 && errno == EINTR);
+
+	return ret;
+}
+
+FIXTURE_SETUP(current_nsset)
+{
+	int i, proc_fd, ret;
+	int ipc_sockets[2];
+	char c;
+
+	for (i = 0; i < PIDFD_NS_MAX; i++) {
+		self->nsfds[i]		= -EBADF;
+		self->child_nsfds1[i]	= -EBADF;
+		self->child_nsfds2[i]	= -EBADF;
+	}
+
+	proc_fd = open("/proc/self/ns", O_DIRECTORY | O_CLOEXEC);
+	ASSERT_GE(proc_fd, 0) {
+		TH_LOG("%m - Failed to open /proc/self/ns");
+	}
+
+	self->pid = getpid();
+	for (i = 0; i < PIDFD_NS_MAX; i++) {
+		const struct ns_info *info = &ns_info[i];
+		self->nsfds[i] = openat(proc_fd, info->name, O_RDONLY | O_CLOEXEC);
+		if (self->nsfds[i] < 0) {
+			EXPECT_EQ(errno, ENOENT) {
+				TH_LOG("%m - Failed to open %s namespace for process %d",
+				       info->name, self->pid);
+			}
+		}
+	}
+
+	self->pidfd = sys_pidfd_open(self->pid, 0);
+	EXPECT_GT(self->pidfd, 0) {
+		TH_LOG("%m - Failed to open pidfd for process %d", self->pid);
+	}
+
+	/* Create task that exits right away. */
+	self->child_pid_exited = create_child(&self->child_pidfd_exited,
+					      CLONE_NEWUSER | CLONE_NEWNET);
+	EXPECT_GT(self->child_pid_exited, 0);
+
+	if (self->child_pid_exited == 0)
+		_exit(EXIT_SUCCESS);
+
+	ASSERT_EQ(sys_waitid(P_PID, self->child_pid_exited, WEXITED | WNOWAIT), 0);
+
+	self->pidfd = sys_pidfd_open(self->pid, 0);
+	EXPECT_GE(self->pidfd, 0) {
+		TH_LOG("%m - Failed to open pidfd for process %d", self->pid);
+	}
+
+	ret = socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
+	EXPECT_EQ(ret, 0);
+
+	/* Create tasks that will be stopped. */
+	self->child_pid1 = create_child(&self->child_pidfd1,
+					CLONE_NEWUSER | CLONE_NEWNS |
+					CLONE_NEWCGROUP | CLONE_NEWIPC |
+					CLONE_NEWUTS | CLONE_NEWPID |
+					CLONE_NEWNET);
+	EXPECT_GE(self->child_pid1, 0);
+
+	if (self->child_pid1 == 0) {
+		close(ipc_sockets[0]);
+
+		if (!switch_timens())
+			_exit(EXIT_FAILURE);
+
+		if (write_nointr(ipc_sockets[1], "1", 1) < 0)
+			_exit(EXIT_FAILURE);
+
+		close(ipc_sockets[1]);
+
+		pause();
+		_exit(EXIT_SUCCESS);
+	}
+
+	close(ipc_sockets[1]);
+	ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
+	close(ipc_sockets[0]);
+
+	ret = socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
+	EXPECT_EQ(ret, 0);
+
+	self->child_pid2 = create_child(&self->child_pidfd2,
+					CLONE_NEWUSER | CLONE_NEWNS |
+					CLONE_NEWCGROUP | CLONE_NEWIPC |
+					CLONE_NEWUTS | CLONE_NEWPID |
+					CLONE_NEWNET);
+	EXPECT_GE(self->child_pid2, 0);
+
+	if (self->child_pid2 == 0) {
+		close(ipc_sockets[0]);
+
+		if (!switch_timens())
+			_exit(EXIT_FAILURE);
+
+		if (write_nointr(ipc_sockets[1], "1", 1) < 0)
+			_exit(EXIT_FAILURE);
+
+		close(ipc_sockets[1]);
+
+		pause();
+		_exit(EXIT_SUCCESS);
+	}
+
+	close(ipc_sockets[1]);
+	ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
+	close(ipc_sockets[0]);
+
+	for (i = 0; i < PIDFD_NS_MAX; i++) {
+		char p[100];
+
+		const struct ns_info *info = &ns_info[i];
+
+		self->nsfds[i] = openat(proc_fd, info->name, O_RDONLY | O_CLOEXEC);
+		if (self->nsfds[i] < 0) {
+			EXPECT_EQ(errno, ENOENT) {
+				TH_LOG("%m - Failed to open %s namespace for process %d",
+				       info->name, self->pid);
+			}
+		}
+
+		ret = snprintf(p, sizeof(p), "/proc/%d/ns/%s",
+			       self->child_pid1, info->name);
+		EXPECT_GT(ret, 0);
+		EXPECT_LT(ret, sizeof(p));
+
+		self->child_nsfds1[i] = open(p, O_RDONLY | O_CLOEXEC);
+		if (self->child_nsfds1[i] < 0) {
+			EXPECT_EQ(errno, ENOENT) {
+				TH_LOG("%m - Failed to open %s namespace for process %d",
+				       info->name, self->child_pid1);
+			}
+		}
+
+		ret = snprintf(p, sizeof(p), "/proc/%d/ns/%s",
+			       self->child_pid2, info->name);
+		EXPECT_GT(ret, 0);
+		EXPECT_LT(ret, sizeof(p));
+
+		self->child_nsfds2[i] = open(p, O_RDONLY | O_CLOEXEC);
+		if (self->child_nsfds2[i] < 0) {
+			EXPECT_EQ(errno, ENOENT) {
+				TH_LOG("%m - Failed to open %s namespace for process %d",
+				       info->name, self->child_pid1);
+			}
+		}
+	}
+
+	close(proc_fd);
+}
+
+FIXTURE_TEARDOWN(current_nsset)
+{
+	int i;
+
+	ASSERT_EQ(sys_pidfd_send_signal(self->child_pidfd1,
+					SIGKILL, NULL, 0), 0);
+	ASSERT_EQ(sys_pidfd_send_signal(self->child_pidfd2,
+					SIGKILL, NULL, 0), 0);
+
+	for (i = 0; i < PIDFD_NS_MAX; i++) {
+		if (self->nsfds[i] >= 0)
+			close(self->nsfds[i]);
+		if (self->child_nsfds1[i] >= 0)
+			close(self->child_nsfds1[i]);
+		if (self->child_nsfds2[i] >= 0)
+			close(self->child_nsfds2[i]);
+	}
+
+	if (self->child_pidfd1 >= 0)
+		EXPECT_EQ(0, close(self->child_pidfd1));
+	if (self->child_pidfd2 >= 0)
+		EXPECT_EQ(0, close(self->child_pidfd2));
+	ASSERT_EQ(sys_waitid(P_PID, self->child_pid_exited, WEXITED), 0);
+	ASSERT_EQ(sys_waitid(P_PID, self->child_pid1, WEXITED), 0);
+	ASSERT_EQ(sys_waitid(P_PID, self->child_pid2, WEXITED), 0);
+}
+
+static int preserve_ns(const int pid, const char *ns)
+{
+	int ret;
+	char path[50];
+
+	ret = snprintf(path, sizeof(path), "/proc/%d/ns/%s", pid, ns);
+	if (ret < 0 || (size_t)ret >= sizeof(path))
+		return -EIO;
+
+	return open(path, O_RDONLY | O_CLOEXEC);
+}
+
+static int in_same_namespace(int ns_fd1, pid_t pid2, const char *ns)
+{
+	int ns_fd2 = -EBADF;
+	int ret = -1;
+	struct stat ns_st1, ns_st2;
+
+	ret = fstat(ns_fd1, &ns_st1);
+	if (ret < 0)
+		return -1;
+
+	ns_fd2 = preserve_ns(pid2, ns);
+	if (ns_fd2 < 0)
+		return -1;
+
+	ret = fstat(ns_fd2, &ns_st2);
+	close(ns_fd2);
+	if (ret < 0)
+		return -1;
+
+	/* processes are in the same namespace */
+	if ((ns_st1.st_dev == ns_st2.st_dev) &&
+	    (ns_st1.st_ino == ns_st2.st_ino))
+		return 1;
+
+	/* processes are in different namespaces */
+	return 0;
+}
+
+/* Test that we can't pass garbage to the kernel. */
+TEST_F(current_nsset, invalid_flags)
+{
+	ASSERT_NE(setns(self->pidfd, 0), 0);
+	EXPECT_EQ(errno, EINVAL);
+
+	ASSERT_NE(setns(self->pidfd, -1), 0);
+	EXPECT_EQ(errno, EINVAL);
+
+	ASSERT_NE(setns(self->pidfd, CLONE_VM), 0);
+	EXPECT_EQ(errno, EINVAL);
+
+	ASSERT_NE(setns(self->pidfd, CLONE_NEWUSER | CLONE_VM), 0);
+	EXPECT_EQ(errno, EINVAL);
+}
+
+/* Test that we can't attach to a task that has already exited. */
+TEST_F(current_nsset, pidfd_exited_child)
+{
+	int i;
+	pid_t pid;
+
+	ASSERT_NE(setns(self->child_pidfd_exited, CLONE_NEWUSER | CLONE_NEWNET),
+		  0);
+	EXPECT_EQ(errno, ESRCH);
+
+	pid = getpid();
+	for (i = 0; i < PIDFD_NS_MAX; i++) {
+		const struct ns_info *info = &ns_info[i];
+		/* Verify that we haven't changed any namespaces. */
+		if (self->nsfds[i] >= 0)
+			ASSERT_EQ(in_same_namespace(self->nsfds[i], pid, info->name), 1);
+	}
+}
+
+TEST_F(current_nsset, pidfd_incremental_setns)
+{
+	int i;
+	pid_t pid;
+
+	pid = getpid();
+	for (i = 0; i < PIDFD_NS_MAX; i++) {
+		const struct ns_info *info = &ns_info[i];
+		int nsfd;
+
+		if (self->child_nsfds1[i] < 0)
+			continue;
+
+		if (info->flag) {
+			ASSERT_EQ(setns(self->child_pidfd1, info->flag), 0) {
+				TH_LOG("%m - Failed to setns to %s namespace of %d via pidfd %d",
+				       info->name, self->child_pid1,
+				       self->child_pidfd1);
+			}
+		}
+
+		/* Verify that we have changed to the correct namespaces. */
+		if (info->flag == CLONE_NEWPID)
+			nsfd = self->nsfds[i];
+		else
+			nsfd = self->child_nsfds1[i];
+		ASSERT_EQ(in_same_namespace(nsfd, pid, info->name), 1) {
+			TH_LOG("setns failed to place us correctly into %s namespace of %d via pidfd %d",
+			       info->name, self->child_pid1,
+			       self->child_pidfd1);
+		}
+		TH_LOG("Managed to correctly setns to %s namespace of %d via pidfd %d",
+		       info->name, self->child_pid1, self->child_pidfd1);
+	}
+}
+
+TEST_F(current_nsset, nsfd_incremental_setns)
+{
+	int i;
+	pid_t pid;
+
+	pid = getpid();
+	for (i = 0; i < PIDFD_NS_MAX; i++) {
+		const struct ns_info *info = &ns_info[i];
+		int nsfd;
+
+		if (self->child_nsfds1[i] < 0)
+			continue;
+
+		if (info->flag) {
+			ASSERT_EQ(setns(self->child_nsfds1[i], info->flag), 0) {
+				TH_LOG("%m - Failed to setns to %s namespace of %d via nsfd %d",
+				       info->name, self->child_pid1,
+				       self->child_nsfds1[i]);
+			}
+		}
+
+		/* Verify that we have changed to the correct namespaces. */
+		if (info->flag == CLONE_NEWPID)
+			nsfd = self->nsfds[i];
+		else
+			nsfd = self->child_nsfds1[i];
+		ASSERT_EQ(in_same_namespace(nsfd, pid, info->name), 1) {
+			TH_LOG("setns failed to place us correctly into %s namespace of %d via nsfd %d",
+			       info->name, self->child_pid1,
+			       self->child_nsfds1[i]);
+		}
+		TH_LOG("Managed to correctly setns to %s namespace of %d via nsfd %d",
+		       info->name, self->child_pid1, self->child_nsfds1[i]);
+	}
+}
+
+TEST_F(current_nsset, pidfd_one_shot_setns)
+{
+	unsigned flags = 0;
+	int i;
+	pid_t pid;
+
+	for (i = 0; i < PIDFD_NS_MAX; i++) {
+		const struct ns_info *info = &ns_info[i];
+
+		if (self->child_nsfds1[i] < 0)
+			continue;
+
+		flags |= info->flag;
+		TH_LOG("Adding %s namespace of %d to list of namespaces to attach to",
+		       info->name, self->child_pid1);
+	}
+
+	ASSERT_EQ(setns(self->child_pidfd1, flags), 0) {
+		TH_LOG("%m - Failed to setns to namespaces of %d",
+		       self->child_pid1);
+	}
+
+	pid = getpid();
+	for (i = 0; i < PIDFD_NS_MAX; i++) {
+		const struct ns_info *info = &ns_info[i];
+		int nsfd;
+
+		if (self->child_nsfds1[i] < 0)
+			continue;
+
+		/* Verify that we have changed to the correct namespaces. */
+		if (info->flag == CLONE_NEWPID)
+			nsfd = self->nsfds[i];
+		else
+			nsfd = self->child_nsfds1[i];
+		ASSERT_EQ(in_same_namespace(nsfd, pid, info->name), 1) {
+			TH_LOG("setns failed to place us correctly into %s namespace of %d",
+			       info->name, self->child_pid1);
+		}
+		TH_LOG("Managed to correctly setns to %s namespace of %d",
+		       info->name, self->child_pid1);
+	}
+}
+
+TEST_F(current_nsset, no_foul_play)
+{
+	unsigned flags = 0;
+	int i;
+
+	for (i = 0; i < PIDFD_NS_MAX; i++) {
+		const struct ns_info *info = &ns_info[i];
+
+		if (self->child_nsfds1[i] < 0)
+			continue;
+
+		flags |= info->flag;
+		if (info->flag) /* No use logging pid_for_children. */
+			TH_LOG("Adding %s namespace of %d to list of namespaces to attach to",
+			       info->name, self->child_pid1);
+	}
+
+	ASSERT_EQ(setns(self->child_pidfd1, flags), 0) {
+		TH_LOG("%m - Failed to setns to namespaces of %d vid pidfd %d",
+		       self->child_pid1, self->child_pidfd1);
+	}
+
+	/*
+	 * Can't setns to a user namespace outside of our hierarchy since we
+	 * don't have caps in there and didn't create it. That means that under
+	 * no circumstances should we be able to setns to any of the other
+	 * ones since they aren't owned by our user namespace.
+	 */
+	for (i = 0; i < PIDFD_NS_MAX; i++) {
+		const struct ns_info *info = &ns_info[i];
+
+		if (self->child_nsfds2[i] < 0 || !info->flag)
+			continue;
+
+		ASSERT_NE(setns(self->child_pidfd2, info->flag), 0) {
+			TH_LOG("Managed to setns to %s namespace of %d via pidfd %d",
+			       info->name, self->child_pid2,
+			       self->child_pidfd2);
+		}
+		TH_LOG("%m - Correctly failed to setns to %s namespace of %d via pidfd %d",
+		       info->name, self->child_pid2,
+		       self->child_pidfd2);
+
+		ASSERT_NE(setns(self->child_nsfds2[i], info->flag), 0) {
+			TH_LOG("Managed to setns to %s namespace of %d via nsfd %d",
+			       info->name, self->child_pid2,
+			       self->child_nsfds2[i]);
+		}
+		TH_LOG("%m - Correctly failed to setns to %s namespace of %d via nsfd %d",
+		       info->name, self->child_pid2,
+		       self->child_nsfds2[i]);
+	}
+}
+
+TEST(setns_einval)
+{
+	int fd;
+
+	fd = sys_memfd_create("rostock", 0);
+	EXPECT_GT(fd, 0);
+
+	ASSERT_NE(setns(fd, 0), 0);
+	EXPECT_EQ(errno, EINVAL);
+	close(fd);
+}
+
+TEST_HARNESS_MAIN