3 files changed, 505 insertions, 0 deletions
diff --git a/tools/testing/selftests/uevent/Makefile b/tools/testing/selftests/uevent/Makefile
new file mode 100644
index 000000000000..f7baa9aa2932
--- /dev/null
+++ b/tools/testing/selftests/uevent/Makefile
@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: GPL-2.0
+all:
+
+include ../lib.mk
+
+.PHONY: all clean
+
+BINARIES := uevent_filtering
+CFLAGS += -Wl,-no-as-needed -Wall
+
+uevent_filtering: uevent_filtering.c ../kselftest.h ../kselftest_harness.h
+	$(CC) $(CFLAGS) $< -o $@
+
+TEST_PROGS += $(BINARIES)
+EXTRA_CLEAN := $(BINARIES)
+
+all: $(BINARIES)
diff --git a/tools/testing/selftests/uevent/config b/tools/testing/selftests/uevent/config
new file mode 100644
index 000000000000..1038f4515be8
--- /dev/null
+++ b/tools/testing/selftests/uevent/config
@@ -0,0 +1,2 @@
+CONFIG_USER_NS=y
+CONFIG_NET=y
diff --git a/tools/testing/selftests/uevent/uevent_filtering.c b/tools/testing/selftests/uevent/uevent_filtering.c
new file mode 100644
index 000000000000..f83391aa42cf
--- /dev/null
+++ b/tools/testing/selftests/uevent/uevent_filtering.c
@@ -0,0 +1,486 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/netlink.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/prctl.h>
+#include <sys/socket.h>
+#include <sched.h>
+#include <sys/eventfd.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "../kselftest.h"
+#include "../kselftest_harness.h"
+
+#define __DEV_FULL "/sys/devices/virtual/mem/full/uevent"
+#define __UEVENT_BUFFER_SIZE (2048 * 2)
+#define __UEVENT_HEADER "add@/devices/virtual/mem/full"
+#define __UEVENT_HEADER_LEN sizeof("add@/devices/virtual/mem/full")
+#define __UEVENT_LISTEN_ALL -1
+
+ssize_t read_nointr(int fd, void *buf, size_t count)
+{
+	ssize_t ret;
+
+again:
+	ret = read(fd, buf, count);
+	if (ret < 0 && errno == EINTR)
+		goto again;
+
+	return ret;
+}
+
+ssize_t write_nointr(int fd, const void *buf, size_t count)
+{
+	ssize_t ret;
+
+again:
+	ret = write(fd, buf, count);
+	if (ret < 0 && errno == EINTR)
+		goto again;
+
+	return ret;
+}
+
+int wait_for_pid(pid_t pid)
+{
+	int status, ret;
+
+again:
+	ret = waitpid(pid, &status, 0);
+	if (ret == -1) {
+		if (errno == EINTR)
+			goto again;
+
+		return -1;
+	}
+
+	if (ret != pid)
+		goto again;
+
+	if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
+		return -1;
+
+	return 0;
+}
+
+static int uevent_listener(unsigned long post_flags, bool expect_uevent,
+			   int sync_fd)
+{
+	int sk_fd, ret;
+	socklen_t sk_addr_len;
+	int fret = -1, rcv_buf_sz = __UEVENT_BUFFER_SIZE;
+	uint64_t sync_add = 1;
+	struct sockaddr_nl sk_addr = { 0 }, rcv_addr = { 0 };
+	char buf[__UEVENT_BUFFER_SIZE] = { 0 };
+	struct iovec iov = { buf, __UEVENT_BUFFER_SIZE };
+	char control[CMSG_SPACE(sizeof(struct ucred))];
+	struct msghdr hdr = {
+		&rcv_addr, sizeof(rcv_addr), &iov, 1,
+		control,   sizeof(control),  0,
+	};
+
+	sk_fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC,
+		       NETLINK_KOBJECT_UEVENT);
+	if (sk_fd < 0) {
+		fprintf(stderr, "%s - Failed to open uevent socket\n", strerror(errno));
+		return -1;
+	}
+
+	ret = setsockopt(sk_fd, SOL_SOCKET, SO_RCVBUF, &rcv_buf_sz,
+			 sizeof(rcv_buf_sz));
+	if (ret < 0) {
+		fprintf(stderr, "%s - Failed to set socket options\n", strerror(errno));
+		goto on_error;
+	}
+
+	sk_addr.nl_family = AF_NETLINK;
+	sk_addr.nl_groups = __UEVENT_LISTEN_ALL;
+
+	sk_addr_len = sizeof(sk_addr);
+	ret = bind(sk_fd, (struct sockaddr *)&sk_addr, sk_addr_len);
+	if (ret < 0) {
+		fprintf(stderr, "%s - Failed to bind socket\n", strerror(errno));
+		goto on_error;
+	}
+
+	ret = getsockname(sk_fd, (struct sockaddr *)&sk_addr, &sk_addr_len);
+	if (ret < 0) {
+		fprintf(stderr, "%s - Failed to retrieve socket name\n", strerror(errno));
+		goto on_error;
+	}
+
+	if ((size_t)sk_addr_len != sizeof(sk_addr)) {
+		fprintf(stderr, "Invalid socket address size\n");
+		goto on_error;
+	}
+
+	if (post_flags & CLONE_NEWUSER) {
+		ret = unshare(CLONE_NEWUSER);
+		if (ret < 0) {
+			fprintf(stderr,
+				"%s - Failed to unshare user namespace\n",
+				strerror(errno));
+			goto on_error;
+		}
+	}
+
+	if (post_flags & CLONE_NEWNET) {
+		ret = unshare(CLONE_NEWNET);
+		if (ret < 0) {
+			fprintf(stderr,
+				"%s - Failed to unshare network namespace\n",
+				strerror(errno));
+			goto on_error;
+		}
+	}
+
+	ret = write_nointr(sync_fd, &sync_add, sizeof(sync_add));
+	close(sync_fd);
+	if (ret != sizeof(sync_add)) {
+		fprintf(stderr, "Failed to synchronize with parent process\n");
+		goto on_error;
+	}
+
+	fret = 0;
+	for (;;) {
+		ssize_t r;
+
+		r = recvmsg(sk_fd, &hdr, 0);
+		if (r <= 0) {
+			fprintf(stderr, "%s - Failed to receive uevent\n", strerror(errno));
+			ret = -1;
+			break;
+		}
+
+		/* ignore libudev messages */
+		if (memcmp(buf, "libudev", 8) == 0)
+			continue;
+
+		/* ignore uevents we didn't trigger */
+		if (memcmp(buf, __UEVENT_HEADER, __UEVENT_HEADER_LEN) != 0)
+			continue;
+
+		if (!expect_uevent) {
+			fprintf(stderr, "Received unexpected uevent:\n");
+			ret = -1;
+		}
+
+		if (TH_LOG_ENABLED) {
+			/* If logging is enabled dump the received uevent. */
+			(void)write_nointr(STDERR_FILENO, buf, r);
+			(void)write_nointr(STDERR_FILENO, "\n", 1);
+		}
+
+		break;
+	}
+
+on_error:
+	close(sk_fd);
+
+	return fret;
+}
+
+int trigger_uevent(unsigned int times)
+{
+	int fd, ret;
+	unsigned int i;
+
+	fd = open(__DEV_FULL, O_RDWR | O_CLOEXEC);
+	if (fd < 0) {
+		if (errno != ENOENT)
+			return -EINVAL;
+
+		return -1;
+	}
+
+	for (i = 0; i < times; i++) {
+		ret = write_nointr(fd, "add\n", sizeof("add\n") - 1);
+		if (ret < 0) {
+			fprintf(stderr, "Failed to trigger uevent\n");
+			break;
+		}
+	}
+	close(fd);
+
+	return ret;
+}
+
+int set_death_signal(void)
+{
+	int ret;
+	pid_t ppid;
+
+	ret = prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
+
+	/* Check whether we have been orphaned. */
+	ppid = getppid();
+	if (ppid == 1) {
+		pid_t self;
+
+		self = getpid();
+		ret = kill(self, SIGKILL);
+	}
+
+	if (ret < 0)
+		return -1;
+
+	return 0;
+}
+
+static int do_test(unsigned long pre_flags, unsigned long post_flags,
+		   bool expect_uevent, int sync_fd)
+{
+	int ret;
+	uint64_t wait_val;
+	pid_t pid;
+	sigset_t mask;
+	sigset_t orig_mask;
+	struct timespec timeout;
+
+	sigemptyset(&mask);
+	sigaddset(&mask, SIGCHLD);
+
+	ret = sigprocmask(SIG_BLOCK, &mask, &orig_mask);
+	if (ret < 0) {
+		fprintf(stderr, "%s- Failed to block SIGCHLD\n", strerror(errno));
+		return -1;
+	}
+
+	pid = fork();
+	if (pid < 0) {
+		fprintf(stderr, "%s - Failed to fork() new process\n", strerror(errno));
+		return -1;
+	}
+
+	if (pid == 0) {
+		/* Make sure that we go away when our parent dies. */
+		ret = set_death_signal();
+		if (ret < 0) {
+			fprintf(stderr, "Failed to set PR_SET_PDEATHSIG to SIGKILL\n");
+			_exit(EXIT_FAILURE);
+		}
+
+		if (pre_flags & CLONE_NEWUSER) {
+			ret = unshare(CLONE_NEWUSER);
+			if (ret < 0) {
+				fprintf(stderr,
+					"%s - Failed to unshare user namespace\n",
+					strerror(errno));
+				_exit(EXIT_FAILURE);
+			}
+		}
+
+		if (pre_flags & CLONE_NEWNET) {
+			ret = unshare(CLONE_NEWNET);
+			if (ret < 0) {
+				fprintf(stderr,
+					"%s - Failed to unshare network namespace\n",
+					strerror(errno));
+				_exit(EXIT_FAILURE);
+			}
+		}
+
+		if (uevent_listener(post_flags, expect_uevent, sync_fd) < 0)
+			_exit(EXIT_FAILURE);
+
+		_exit(EXIT_SUCCESS);
+	}
+
+	ret = read_nointr(sync_fd, &wait_val, sizeof(wait_val));
+	if (ret != sizeof(wait_val)) {
+		fprintf(stderr, "Failed to synchronize with child process\n");
+		_exit(EXIT_FAILURE);
+	}
+
+	/* Trigger 10 uevents to account for the case where the kernel might
+	 * drop some.
+	 */
+	ret = trigger_uevent(10);
+	if (ret < 0)
+		fprintf(stderr, "Failed triggering uevents\n");
+
+	/* Wait for 2 seconds before considering this failed. This should be
+	 * plenty of time for the kernel to deliver the uevent even under heavy
+	 * load.
+	 */
+	timeout.tv_sec = 2;
+	timeout.tv_nsec = 0;
+
+again:
+	ret = sigtimedwait(&mask, NULL, &timeout);
+	if (ret < 0) {
+		if (errno == EINTR)
+			goto again;
+
+		if (!expect_uevent)
+			ret = kill(pid, SIGTERM); /* success */
+		else
+			ret = kill(pid, SIGUSR1); /* error */
+		if (ret < 0)
+			return -1;
+	}
+
+	ret = wait_for_pid(pid);
+	if (ret < 0)
+		return -1;
+
+	return ret;
+}
+
+static void signal_handler(int sig)
+{
+	if (sig == SIGTERM)
+		_exit(EXIT_SUCCESS);
+
+	_exit(EXIT_FAILURE);
+}
+
+TEST(uevent_filtering)
+{
+	int ret, sync_fd;
+	struct sigaction act;
+
+	if (geteuid()) {
+		TH_LOG("Uevent filtering tests require root privileges. Skipping test");
+		_exit(KSFT_SKIP);
+	}
+
+	ret = access(__DEV_FULL, F_OK);
+	EXPECT_EQ(0, ret) {
+		if (errno == ENOENT) {
+			TH_LOG(__DEV_FULL " does not exist. Skipping test");
+			_exit(KSFT_SKIP);
+		}
+
+		_exit(KSFT_FAIL);
+	}
+
+	act.sa_handler = signal_handler;
+	act.sa_flags = 0;
+	sigemptyset(&act.sa_mask);
+
+	ret = sigaction(SIGTERM, &act, NULL);
+	ASSERT_EQ(0, ret);
+
+	sync_fd = eventfd(0, EFD_CLOEXEC);
+	ASSERT_GE(sync_fd, 0);
+
+	/*
+	 * Setup:
+	 * - Open uevent listening socket in initial network namespace owned by
+	 *   initial user namespace.
+	 * - Trigger uevent in initial network namespace owned by initial user
+	 *   namespace.
+	 * Expected Result:
+	 * - uevent listening socket receives uevent
+	 */
+	ret = do_test(0, 0, true, sync_fd);
+	ASSERT_EQ(0, ret) {
+		goto do_cleanup;
+	}
+
+	/*
+	 * Setup:
+	 * - Open uevent listening socket in non-initial network namespace
+	 *   owned by initial user namespace.
+	 * - Trigger uevent in initial network namespace owned by initial user
+	 *   namespace.
+	 * Expected Result:
+	 * - uevent listening socket receives uevent
+	 */
+	ret = do_test(CLONE_NEWNET, 0, true, sync_fd);
+	ASSERT_EQ(0, ret) {
+		goto do_cleanup;
+	}
+
+	/*
+	 * Setup:
+	 * - unshare user namespace
+	 * - Open uevent listening socket in initial network namespace
+	 *   owned by initial user namespace.
+	 * - Trigger uevent in initial network namespace owned by initial user
+	 *   namespace.
+	 * Expected Result:
+	 * - uevent listening socket receives uevent
+	 */
+	ret = do_test(CLONE_NEWUSER, 0, true, sync_fd);
+	ASSERT_EQ(0, ret) {
+		goto do_cleanup;
+	}
+
+	/*
+	 * Setup:
+	 * - Open uevent listening socket in non-initial network namespace
+	 *   owned by non-initial user namespace.
+	 * - Trigger uevent in initial network namespace owned by initial user
+	 *   namespace.
+	 * Expected Result:
+	 * - uevent listening socket receives no uevent
+	 */
+	ret = do_test(CLONE_NEWUSER | CLONE_NEWNET, 0, false, sync_fd);
+	ASSERT_EQ(0, ret) {
+		goto do_cleanup;
+	}
+
+	/*
+	 * Setup:
+	 * - Open uevent listening socket in initial network namespace
+	 *   owned by initial user namespace.
+	 * - unshare network namespace
+	 * - Trigger uevent in initial network namespace owned by initial user
+	 *   namespace.
+	 * Expected Result:
+	 * - uevent listening socket receives uevent
+	 */
+	ret = do_test(0, CLONE_NEWNET, true, sync_fd);
+	ASSERT_EQ(0, ret) {
+		goto do_cleanup;
+	}
+
+	/*
+	 * Setup:
+	 * - Open uevent listening socket in initial network namespace
+	 *   owned by initial user namespace.
+	 * - unshare user namespace
+	 * - Trigger uevent in initial network namespace owned by initial user
+	 *   namespace.
+	 * Expected Result:
+	 * - uevent listening socket receives uevent
+	 */
+	ret = do_test(0, CLONE_NEWUSER, true, sync_fd);
+	ASSERT_EQ(0, ret) {
+		goto do_cleanup;
+	}
+
+	/*
+	 * Setup:
+	 * - Open uevent listening socket in initial network namespace
+	 *   owned by initial user namespace.
+	 * - unshare user namespace
+	 * - unshare network namespace
+	 * - Trigger uevent in initial network namespace owned by initial user
+	 *   namespace.
+	 * Expected Result:
+	 * - uevent listening socket receives uevent
+	 */
+	ret = do_test(0, CLONE_NEWUSER | CLONE_NEWNET, true, sync_fd);
+	ASSERT_EQ(0, ret) {
+		goto do_cleanup;
+	}
+
+do_cleanup:
+	close(sync_fd);
+}
+
+TEST_HARNESS_MAIN