[mirror_ubuntu-jammy-kernel.git] / tools / testing / selftests / memfd / memfd_test.c

#define _GNU_SOURCE
#define __EXPORTED_HEADERS__

#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <linux/falloc.h>
#include <linux/fcntl.h>
#include <linux/memfd.h>
#include <sched.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/wait.h>
#include <unistd.h>

#define MFD_DEF_SIZE 8192
#define STACK_SIZE 65536

static int sys_memfd_create(const char *name,
			    unsigned int flags)
{
	return syscall(__NR_memfd_create, name, flags);
}

static int mfd_assert_new(const char *name, loff_t sz, unsigned int flags)
{
	int r, fd;

	fd = sys_memfd_create(name, flags);
	if (fd < 0) {
		printf("memfd_create(\"%s\", %u) failed: %m\n",
		       name, flags);
		abort();
	}

	r = ftruncate(fd, sz);
	if (r < 0) {
		printf("ftruncate(%llu) failed: %m\n", (unsigned long long)sz);
		abort();
	}

	return fd;
}

static void mfd_fail_new(const char *name, unsigned int flags)
{
	int r;

	r = sys_memfd_create(name, flags);
	if (r >= 0) {
		printf("memfd_create(\"%s\", %u) succeeded, but failure expected\n",
		       name, flags);
		close(r);
		abort();
	}
}

static unsigned int mfd_assert_get_seals(int fd)
{
	int r;

	r = fcntl(fd, F_GET_SEALS);
	if (r < 0) {
		printf("GET_SEALS(%d) failed: %m\n", fd);
		abort();
	}

	return (unsigned int)r;
}

static void mfd_assert_has_seals(int fd, unsigned int seals)
{
	unsigned int s;

	s = mfd_assert_get_seals(fd);
	if (s != seals) {
		printf("%u != %u = GET_SEALS(%d)\n", seals, s, fd);
		abort();
	}
}

static void mfd_assert_add_seals(int fd, unsigned int seals)
{
	int r;
	unsigned int s;

	s = mfd_assert_get_seals(fd);
	r = fcntl(fd, F_ADD_SEALS, seals);
	if (r < 0) {
		printf("ADD_SEALS(%d, %u -> %u) failed: %m\n", fd, s, seals);
		abort();
	}
}

static void mfd_fail_add_seals(int fd, unsigned int seals)
{
	int r;
	unsigned int s;

	r = fcntl(fd, F_GET_SEALS);
	if (r < 0)
		s = 0;
	else
		s = (unsigned int)r;

	r = fcntl(fd, F_ADD_SEALS, seals);
	if (r >= 0) {
		printf("ADD_SEALS(%d, %u -> %u) didn't fail as expected\n",
				fd, s, seals);
		abort();
	}
}

static void mfd_assert_size(int fd, size_t size)
{
	struct stat st;
	int r;

	r = fstat(fd, &st);
	if (r < 0) {
		printf("fstat(%d) failed: %m\n", fd);
		abort();
	} else if (st.st_size != size) {
		printf("wrong file size %lld, but expected %lld\n",
		       (long long)st.st_size, (long long)size);
		abort();
	}
}

static int mfd_assert_dup(int fd)
{
	int r;

	r = dup(fd);
	if (r < 0) {
		printf("dup(%d) failed: %m\n", fd);
		abort();
	}

	return r;
}

static void *mfd_assert_mmap_shared(int fd)
{
	void *p;

	p = mmap(NULL,
		 MFD_DEF_SIZE,
		 PROT_READ | PROT_WRITE,
		 MAP_SHARED,
		 fd,
		 0);
	if (p == MAP_FAILED) {
		printf("mmap() failed: %m\n");
		abort();
	}

	return p;
}

static void *mfd_assert_mmap_private(int fd)
{
	void *p;

	p = mmap(NULL,
		 MFD_DEF_SIZE,
		 PROT_READ,
		 MAP_PRIVATE,
		 fd,
		 0);
	if (p == MAP_FAILED) {
		printf("mmap() failed: %m\n");
		abort();
	}

	return p;
}

static int mfd_assert_open(int fd, int flags, mode_t mode)
{
	char buf[512];
	int r;

	sprintf(buf, "/proc/self/fd/%d", fd);
	r = open(buf, flags, mode);
	if (r < 0) {
		printf("open(%s) failed: %m\n", buf);
		abort();
	}

	return r;
}

static void mfd_fail_open(int fd, int flags, mode_t mode)
{
	char buf[512];
	int r;

	sprintf(buf, "/proc/self/fd/%d", fd);
	r = open(buf, flags, mode);
	if (r >= 0) {
		printf("open(%s) didn't fail as expected\n", buf);
		abort();
	}
}

static void mfd_assert_read(int fd)
{
	char buf[16];
	void *p;
	ssize_t l;

	l = read(fd, buf, sizeof(buf));
	if (l != sizeof(buf)) {
		printf("read() failed: %m\n");
		abort();
	}

	/* verify PROT_READ *is* allowed */
	p = mmap(NULL,
		 MFD_DEF_SIZE,
		 PROT_READ,
		 MAP_PRIVATE,
		 fd,
		 0);
	if (p == MAP_FAILED) {
		printf("mmap() failed: %m\n");
		abort();
	}
	munmap(p, MFD_DEF_SIZE);

	/* verify MAP_PRIVATE is *always* allowed (even writable) */
	p = mmap(NULL,
		 MFD_DEF_SIZE,
		 PROT_READ | PROT_WRITE,
		 MAP_PRIVATE,
		 fd,
		 0);
	if (p == MAP_FAILED) {
		printf("mmap() failed: %m\n");
		abort();
	}
	munmap(p, MFD_DEF_SIZE);
}

static void mfd_assert_write(int fd)
{
	ssize_t l;
	void *p;
	int r;

	/* verify write() succeeds */
	l = write(fd, "\0\0\0\0", 4);
	if (l != 4) {
		printf("write() failed: %m\n");
		abort();
	}

	/* verify PROT_READ | PROT_WRITE is allowed */
	p = mmap(NULL,
		 MFD_DEF_SIZE,
		 PROT_READ | PROT_WRITE,
		 MAP_SHARED,
		 fd,
		 0);
	if (p == MAP_FAILED) {
		printf("mmap() failed: %m\n");
		abort();
	}
	*(char *)p = 0;
	munmap(p, MFD_DEF_SIZE);

	/* verify PROT_WRITE is allowed */
	p = mmap(NULL,
		 MFD_DEF_SIZE,
		 PROT_WRITE,
		 MAP_SHARED,
		 fd,
		 0);
	if (p == MAP_FAILED) {
		printf("mmap() failed: %m\n");
		abort();
	}
	*(char *)p = 0;
	munmap(p, MFD_DEF_SIZE);

	/* verify PROT_READ with MAP_SHARED is allowed and a following
	 * mprotect(PROT_WRITE) allows writing */
	p = mmap(NULL,
		 MFD_DEF_SIZE,
		 PROT_READ,
		 MAP_SHARED,
		 fd,
		 0);
	if (p == MAP_FAILED) {
		printf("mmap() failed: %m\n");
		abort();
	}

	r = mprotect(p, MFD_DEF_SIZE, PROT_READ | PROT_WRITE);
	if (r < 0) {
		printf("mprotect() failed: %m\n");
		abort();
	}

	*(char *)p = 0;
	munmap(p, MFD_DEF_SIZE);

	/* verify PUNCH_HOLE works */
	r = fallocate(fd,
		      FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
		      0,
		      MFD_DEF_SIZE);
	if (r < 0) {
		printf("fallocate(PUNCH_HOLE) failed: %m\n");
		abort();
	}
}

static void mfd_fail_write(int fd)
{
	ssize_t l;
	void *p;
	int r;

	/* verify write() fails */
	l = write(fd, "data", 4);
	if (l != -EPERM) {
		printf("expected EPERM on write(), but got %d: %m\n", (int)l);
		abort();
	}

	/* verify PROT_READ | PROT_WRITE is not allowed */
	p = mmap(NULL,
		 MFD_DEF_SIZE,
		 PROT_READ | PROT_WRITE,
		 MAP_SHARED,
		 fd,
		 0);
	if (p != MAP_FAILED) {
		printf("mmap() didn't fail as expected\n");
		abort();
	}

	/* verify PROT_WRITE is not allowed */
	p = mmap(NULL,
		 MFD_DEF_SIZE,
		 PROT_WRITE,
		 MAP_SHARED,
		 fd,
		 0);
	if (p != MAP_FAILED) {
		printf("mmap() didn't fail as expected\n");
		abort();
	}

	/* Verify PROT_READ with MAP_SHARED with a following mprotect is not
	 * allowed. Note that for r/w the kernel already prevents the mmap. */
	p = mmap(NULL,
		 MFD_DEF_SIZE,
		 PROT_READ,
		 MAP_SHARED,
		 fd,
		 0);
	if (p != MAP_FAILED) {
		r = mprotect(p, MFD_DEF_SIZE, PROT_READ | PROT_WRITE);
		if (r >= 0) {
			printf("mmap()+mprotect() didn't fail as expected\n");
			abort();
		}
	}

	/* verify PUNCH_HOLE fails */
	r = fallocate(fd,
		      FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
		      0,
		      MFD_DEF_SIZE);
	if (r >= 0) {
		printf("fallocate(PUNCH_HOLE) didn't fail as expected\n");
		abort();
	}
}

static void mfd_assert_shrink(int fd)
{
	int r, fd2;

	r = ftruncate(fd, MFD_DEF_SIZE / 2);
	if (r < 0) {
		printf("ftruncate(SHRINK) failed: %m\n");
		abort();
	}

	mfd_assert_size(fd, MFD_DEF_SIZE / 2);

	fd2 = mfd_assert_open(fd,
			      O_RDWR | O_CREAT | O_TRUNC,
			      S_IRUSR | S_IWUSR);
	close(fd2);

	mfd_assert_size(fd, 0);
}

static void mfd_fail_shrink(int fd)
{
	int r;

	r = ftruncate(fd, MFD_DEF_SIZE / 2);
	if (r >= 0) {
		printf("ftruncate(SHRINK) didn't fail as expected\n");
		abort();
	}

	mfd_fail_open(fd,
		      O_RDWR | O_CREAT | O_TRUNC,
		      S_IRUSR | S_IWUSR);
}

static void mfd_assert_grow(int fd)
{
	int r;

	r = ftruncate(fd, MFD_DEF_SIZE * 2);
	if (r < 0) {
		printf("ftruncate(GROW) failed: %m\n");
		abort();
	}

	mfd_assert_size(fd, MFD_DEF_SIZE * 2);

	r = fallocate(fd,
		      0,
		      0,
		      MFD_DEF_SIZE * 4);
	if (r < 0) {
		printf("fallocate(ALLOC) failed: %m\n");
		abort();
	}

	mfd_assert_size(fd, MFD_DEF_SIZE * 4);
}

static void mfd_fail_grow(int fd)
{
	int r;

	r = ftruncate(fd, MFD_DEF_SIZE * 2);
	if (r >= 0) {
		printf("ftruncate(GROW) didn't fail as expected\n");
		abort();
	}

	r = fallocate(fd,
		      0,
		      0,
		      MFD_DEF_SIZE * 4);
	if (r >= 0) {
		printf("fallocate(ALLOC) didn't fail as expected\n");
		abort();
	}
}

static void mfd_assert_grow_write(int fd)
{
	static char buf[MFD_DEF_SIZE * 8];
	ssize_t l;

	l = pwrite(fd, buf, sizeof(buf), 0);
	if (l != sizeof(buf)) {
		printf("pwrite() failed: %m\n");
		abort();
	}

	mfd_assert_size(fd, MFD_DEF_SIZE * 8);
}

static void mfd_fail_grow_write(int fd)
{
	static char buf[MFD_DEF_SIZE * 8];
	ssize_t l;

	l = pwrite(fd, buf, sizeof(buf), 0);
	if (l == sizeof(buf)) {
		printf("pwrite() didn't fail as expected\n");
		abort();
	}
}

static int idle_thread_fn(void *arg)
{
	sigset_t set;
	int sig;

	/* dummy waiter; SIGTERM terminates us anyway */
	sigemptyset(&set);
	sigaddset(&set, SIGTERM);
	sigwait(&set, &sig);

	return 0;
}

static pid_t spawn_idle_thread(unsigned int flags)
{
	uint8_t *stack;
	pid_t pid;

	stack = malloc(STACK_SIZE);
	if (!stack) {
		printf("malloc(STACK_SIZE) failed: %m\n");
		abort();
	}

	pid = clone(idle_thread_fn,
		    stack + STACK_SIZE,
		    SIGCHLD | flags,
		    NULL);
	if (pid < 0) {
		printf("clone() failed: %m\n");
		abort();
	}

	return pid;
}

static void join_idle_thread(pid_t pid)
{
	kill(pid, SIGTERM);
	waitpid(pid, NULL, 0);
}

/*
 * Test memfd_create() syscall
 * Verify syscall-argument validation, including name checks, flag validation
 * and more.
 */
static void test_create(void)
{
	char buf[2048];
	int fd;

	/* test NULL name */
	mfd_fail_new(NULL, 0);

	/* test over-long name (not zero-terminated) */
	memset(buf, 0xff, sizeof(buf));
	mfd_fail_new(buf, 0);

	/* test over-long zero-terminated name */
	memset(buf, 0xff, sizeof(buf));
	buf[sizeof(buf) - 1] = 0;
	mfd_fail_new(buf, 0);

	/* verify "" is a valid name */
	fd = mfd_assert_new("", 0, 0);
	close(fd);

	/* verify invalid O_* open flags */
	mfd_fail_new("", 0x0100);
	mfd_fail_new("", ~MFD_CLOEXEC);
	mfd_fail_new("", ~MFD_ALLOW_SEALING);
	mfd_fail_new("", ~0);
	mfd_fail_new("", 0x80000000U);

	/* verify MFD_CLOEXEC is allowed */
	fd = mfd_assert_new("", 0, MFD_CLOEXEC);
	close(fd);

	/* verify MFD_ALLOW_SEALING is allowed */
	fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING);
	close(fd);

	/* verify MFD_ALLOW_SEALING | MFD_CLOEXEC is allowed */
	fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING | MFD_CLOEXEC);
	close(fd);
}

/*
 * Test basic sealing
 * A very basic sealing test to see whether setting/retrieving seals works.
 */
static void test_basic(void)
{
	int fd;

	fd = mfd_assert_new("kern_memfd_basic",
			    MFD_DEF_SIZE,
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);

	/* add basic seals */
	mfd_assert_has_seals(fd, 0);
	mfd_assert_add_seals(fd, F_SEAL_SHRINK |
				 F_SEAL_WRITE);
	mfd_assert_has_seals(fd, F_SEAL_SHRINK |
				 F_SEAL_WRITE);

	/* add them again */
	mfd_assert_add_seals(fd, F_SEAL_SHRINK |
				 F_SEAL_WRITE);
	mfd_assert_has_seals(fd, F_SEAL_SHRINK |
				 F_SEAL_WRITE);

	/* add more seals and seal against sealing */
	mfd_assert_add_seals(fd, F_SEAL_GROW | F_SEAL_SEAL);
	mfd_assert_has_seals(fd, F_SEAL_SHRINK |
				 F_SEAL_GROW |
				 F_SEAL_WRITE |
				 F_SEAL_SEAL);

	/* verify that sealing no longer works */
	mfd_fail_add_seals(fd, F_SEAL_GROW);
	mfd_fail_add_seals(fd, 0);

	close(fd);

	/* verify sealing does not work without MFD_ALLOW_SEALING */
	fd = mfd_assert_new("kern_memfd_basic",
			    MFD_DEF_SIZE,
			    MFD_CLOEXEC);
	mfd_assert_has_seals(fd, F_SEAL_SEAL);
	mfd_fail_add_seals(fd, F_SEAL_SHRINK |
			       F_SEAL_GROW |
			       F_SEAL_WRITE);
	mfd_assert_has_seals(fd, F_SEAL_SEAL);
	close(fd);
}

/*
 * Test SEAL_WRITE
 * Test whether SEAL_WRITE actually prevents modifications.
 */
static void test_seal_write(void)
{
	int fd;

	fd = mfd_assert_new("kern_memfd_seal_write",
			    MFD_DEF_SIZE,
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
	mfd_assert_has_seals(fd, 0);
	mfd_assert_add_seals(fd, F_SEAL_WRITE);
	mfd_assert_has_seals(fd, F_SEAL_WRITE);

	mfd_assert_read(fd);
	mfd_fail_write(fd);
	mfd_assert_shrink(fd);
	mfd_assert_grow(fd);
	mfd_fail_grow_write(fd);

	close(fd);
}

/*
 * Test SEAL_SHRINK
 * Test whether SEAL_SHRINK actually prevents shrinking
 */
static void test_seal_shrink(void)
{
	int fd;

	fd = mfd_assert_new("kern_memfd_seal_shrink",
			    MFD_DEF_SIZE,
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
	mfd_assert_has_seals(fd, 0);
	mfd_assert_add_seals(fd, F_SEAL_SHRINK);
	mfd_assert_has_seals(fd, F_SEAL_SHRINK);

	mfd_assert_read(fd);
	mfd_assert_write(fd);
	mfd_fail_shrink(fd);
	mfd_assert_grow(fd);
	mfd_assert_grow_write(fd);

	close(fd);
}

/*
 * Test SEAL_GROW
 * Test whether SEAL_GROW actually prevents growing
 */
static void test_seal_grow(void)
{
	int fd;

	fd = mfd_assert_new("kern_memfd_seal_grow",
			    MFD_DEF_SIZE,
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
	mfd_assert_has_seals(fd, 0);
	mfd_assert_add_seals(fd, F_SEAL_GROW);
	mfd_assert_has_seals(fd, F_SEAL_GROW);

	mfd_assert_read(fd);
	mfd_assert_write(fd);
	mfd_assert_shrink(fd);
	mfd_fail_grow(fd);
	mfd_fail_grow_write(fd);

	close(fd);
}

/*
 * Test SEAL_SHRINK | SEAL_GROW
 * Test whether SEAL_SHRINK | SEAL_GROW actually prevents resizing
 */
static void test_seal_resize(void)
{
	int fd;

	fd = mfd_assert_new("kern_memfd_seal_resize",
			    MFD_DEF_SIZE,
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
	mfd_assert_has_seals(fd, 0);
	mfd_assert_add_seals(fd, F_SEAL_SHRINK | F_SEAL_GROW);
	mfd_assert_has_seals(fd, F_SEAL_SHRINK | F_SEAL_GROW);

	mfd_assert_read(fd);
	mfd_assert_write(fd);
	mfd_fail_shrink(fd);
	mfd_fail_grow(fd);
	mfd_fail_grow_write(fd);

	close(fd);
}

/*
 * Test sharing via dup()
 * Test that seals are shared between dupped FDs and they're all equal.
 */
static void test_share_dup(void)
{
	int fd, fd2;

	fd = mfd_assert_new("kern_memfd_share_dup",
			    MFD_DEF_SIZE,
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
	mfd_assert_has_seals(fd, 0);

	fd2 = mfd_assert_dup(fd);
	mfd_assert_has_seals(fd2, 0);

	mfd_assert_add_seals(fd, F_SEAL_WRITE);
	mfd_assert_has_seals(fd, F_SEAL_WRITE);
	mfd_assert_has_seals(fd2, F_SEAL_WRITE);

	mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);

	mfd_assert_add_seals(fd, F_SEAL_SEAL);
	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);

	mfd_fail_add_seals(fd, F_SEAL_GROW);
	mfd_fail_add_seals(fd2, F_SEAL_GROW);
	mfd_fail_add_seals(fd, F_SEAL_SEAL);
	mfd_fail_add_seals(fd2, F_SEAL_SEAL);

	close(fd2);

	mfd_fail_add_seals(fd, F_SEAL_GROW);
	close(fd);
}

/*
 * Test sealing with active mmap()s
 * Modifying seals is only allowed if no other mmap() refs exist.
 */
static void test_share_mmap(void)
{
	int fd;
	void *p;

	fd = mfd_assert_new("kern_memfd_share_mmap",
			    MFD_DEF_SIZE,
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
	mfd_assert_has_seals(fd, 0);

	/* shared/writable ref prevents sealing WRITE, but allows others */
	p = mfd_assert_mmap_shared(fd);
	mfd_fail_add_seals(fd, F_SEAL_WRITE);
	mfd_assert_has_seals(fd, 0);
	mfd_assert_add_seals(fd, F_SEAL_SHRINK);
	mfd_assert_has_seals(fd, F_SEAL_SHRINK);
	munmap(p, MFD_DEF_SIZE);

	/* readable ref allows sealing */
	p = mfd_assert_mmap_private(fd);
	mfd_assert_add_seals(fd, F_SEAL_WRITE);
	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
	munmap(p, MFD_DEF_SIZE);

	close(fd);
}

/*
 * Test sealing with open(/proc/self/fd/%d)
 * Via /proc we can get access to a separate file-context for the same memfd.
 * This is *not* like dup(), but like a real separate open(). Make sure the
 * semantics are as expected and we correctly check for RDONLY / WRONLY / RDWR.
 */
static void test_share_open(void)
{
	int fd, fd2;

	fd = mfd_assert_new("kern_memfd_share_open",
			    MFD_DEF_SIZE,
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
	mfd_assert_has_seals(fd, 0);

	fd2 = mfd_assert_open(fd, O_RDWR, 0);
	mfd_assert_add_seals(fd, F_SEAL_WRITE);
	mfd_assert_has_seals(fd, F_SEAL_WRITE);
	mfd_assert_has_seals(fd2, F_SEAL_WRITE);

	mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);

	close(fd);
	fd = mfd_assert_open(fd2, O_RDONLY, 0);

	mfd_fail_add_seals(fd, F_SEAL_SEAL);
	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);

	close(fd2);
	fd2 = mfd_assert_open(fd, O_RDWR, 0);

	mfd_assert_add_seals(fd2, F_SEAL_SEAL);
	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);

	close(fd2);
	close(fd);
}

/*
 * Test sharing via fork()
 * Test whether seal-modifications work as expected with forked childs.
 */
static void test_share_fork(void)
{
	int fd;
	pid_t pid;

	fd = mfd_assert_new("kern_memfd_share_fork",
			    MFD_DEF_SIZE,
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
	mfd_assert_has_seals(fd, 0);

	pid = spawn_idle_thread(0);
	mfd_assert_add_seals(fd, F_SEAL_SEAL);
	mfd_assert_has_seals(fd, F_SEAL_SEAL);

	mfd_fail_add_seals(fd, F_SEAL_WRITE);
	mfd_assert_has_seals(fd, F_SEAL_SEAL);

	join_idle_thread(pid);

	mfd_fail_add_seals(fd, F_SEAL_WRITE);
	mfd_assert_has_seals(fd, F_SEAL_SEAL);

	close(fd);
}

int main(int argc, char **argv)
{
	pid_t pid;

	printf("memfd: CREATE\n");
	test_create();
	printf("memfd: BASIC\n");
	test_basic();

	printf("memfd: SEAL-WRITE\n");
	test_seal_write();
	printf("memfd: SEAL-SHRINK\n");
	test_seal_shrink();
	printf("memfd: SEAL-GROW\n");
	test_seal_grow();
	printf("memfd: SEAL-RESIZE\n");
	test_seal_resize();

	printf("memfd: SHARE-DUP\n");
	test_share_dup();
	printf("memfd: SHARE-MMAP\n");
	test_share_mmap();
	printf("memfd: SHARE-OPEN\n");
	test_share_open();
	printf("memfd: SHARE-FORK\n");
	test_share_fork();

	/* Run test-suite in a multi-threaded environment with a shared
	 * file-table. */
	pid = spawn_idle_thread(CLONE_FILES | CLONE_FS | CLONE_VM);
	printf("memfd: SHARE-DUP (shared file-table)\n");
	test_share_dup();
	printf("memfd: SHARE-MMAP (shared file-table)\n");
	test_share_mmap();
	printf("memfd: SHARE-OPEN (shared file-table)\n");
	test_share_open();
	printf("memfd: SHARE-FORK (shared file-table)\n");
	test_share_fork();
	join_idle_thread(pid);

	printf("memfd: DONE\n");

	return 0;
}
Commit	Line	Data
4f5ce5e8 DH	1	#define _GNU_SOURCE
	2	#define __EXPORTED_HEADERS__
	3
	4	#include <errno.h>
	5	#include <inttypes.h>
	6	#include <limits.h>
	7	#include <linux/falloc.h>
	8	#include <linux/fcntl.h>
	9	#include <linux/memfd.h>
	10	#include <sched.h>
	11	#include <stdio.h>
	12	#include <stdlib.h>
	13	#include <signal.h>
	14	#include <string.h>
	15	#include <sys/mman.h>
	16	#include <sys/stat.h>
	17	#include <sys/syscall.h>
c1ee4831	18	#include <sys/wait.h>
4f5ce5e8 DH	19	#include <unistd.h>
	20
	21	#define MFD_DEF_SIZE 8192
1f78dda2	22	#define STACK_SIZE 65536
4f5ce5e8 DH	23
	24	static int sys_memfd_create(const char *name,
	25	unsigned int flags)
	26	{
	27	return syscall(__NR_memfd_create, name, flags);
	28	}
	29
	30	static int mfd_assert_new(const char *name, loff_t sz, unsigned int flags)
	31	{
	32	int r, fd;
	33
	34	fd = sys_memfd_create(name, flags);
	35	if (fd < 0) {
	36	printf("memfd_create(\"%s\", %u) failed: %m\n",
	37	name, flags);
	38	abort();
	39	}
	40
	41	r = ftruncate(fd, sz);
	42	if (r < 0) {
	43	printf("ftruncate(%llu) failed: %m\n", (unsigned long long)sz);
	44	abort();
	45	}
	46
	47	return fd;
	48	}
	49
	50	static void mfd_fail_new(const char *name, unsigned int flags)
	51	{
	52	int r;
	53
	54	r = sys_memfd_create(name, flags);
	55	if (r >= 0) {
	56	printf("memfd_create(\"%s\", %u) succeeded, but failure expected\n",
	57	name, flags);
	58	close(r);
	59	abort();
	60	}
	61	}
	62
57e67900	63	static unsigned int mfd_assert_get_seals(int fd)
4f5ce5e8	64	{
57e67900	65	int r;
4f5ce5e8 DH	66
	67	r = fcntl(fd, F_GET_SEALS);
	68	if (r < 0) {
	69	printf("GET_SEALS(%d) failed: %m\n", fd);
	70	abort();
	71	}
	72
57e67900	73	return (unsigned int)r;
4f5ce5e8 DH	74	}
4f5ce5e8 DH	75
57e67900	76	static void mfd_assert_has_seals(int fd, unsigned int seals)
4f5ce5e8	77	{
57e67900	78	unsigned int s;
4f5ce5e8 DH	79
	80	s = mfd_assert_get_seals(fd);
	81	if (s != seals) {
57e67900	82	printf("%u != %u = GET_SEALS(%d)\n", seals, s, fd);
4f5ce5e8 DH	83	abort();
	84	}
	85	}
	86
57e67900	87	static void mfd_assert_add_seals(int fd, unsigned int seals)
4f5ce5e8	88	{
57e67900 PK	89	int r;
57e67900 PK	90	unsigned int s;
4f5ce5e8 DH	91
	92	s = mfd_assert_get_seals(fd);
	93	r = fcntl(fd, F_ADD_SEALS, seals);
	94	if (r < 0) {
57e67900	95	printf("ADD_SEALS(%d, %u -> %u) failed: %m\n", fd, s, seals);
4f5ce5e8 DH	96	abort();
	97	}
	98	}
	99
57e67900	100	static void mfd_fail_add_seals(int fd, unsigned int seals)
4f5ce5e8	101	{
57e67900 PK	102	int r;
57e67900 PK	103	unsigned int s;
4f5ce5e8 DH	104
	105	r = fcntl(fd, F_GET_SEALS);
	106	if (r < 0)
	107	s = 0;
	108	else
57e67900	109	s = (unsigned int)r;
4f5ce5e8 DH	110
	111	r = fcntl(fd, F_ADD_SEALS, seals);
	112	if (r >= 0) {
57e67900 PK	113	printf("ADD_SEALS(%d, %u -> %u) didn't fail as expected\n",
57e67900 PK	114	fd, s, seals);
4f5ce5e8 DH	115	abort();
	116	}
	117	}
	118
	119	static void mfd_assert_size(int fd, size_t size)
	120	{
	121	struct stat st;
	122	int r;
	123
	124	r = fstat(fd, &st);
	125	if (r < 0) {
	126	printf("fstat(%d) failed: %m\n", fd);
	127	abort();
	128	} else if (st.st_size != size) {
	129	printf("wrong file size %lld, but expected %lld\n",
	130	(long long)st.st_size, (long long)size);
	131	abort();
	132	}
	133	}
	134
	135	static int mfd_assert_dup(int fd)
	136	{
	137	int r;
	138
	139	r = dup(fd);
	140	if (r < 0) {
	141	printf("dup(%d) failed: %m\n", fd);
	142	abort();
	143	}
	144
	145	return r;
	146	}
	147
	148	static void *mfd_assert_mmap_shared(int fd)
	149	{
	150	void *p;
	151
	152	p = mmap(NULL,
	153	MFD_DEF_SIZE,
	154	PROT_READ \| PROT_WRITE,
	155	MAP_SHARED,
	156	fd,
	157	0);
	158	if (p == MAP_FAILED) {
	159	printf("mmap() failed: %m\n");
	160	abort();
	161	}
	162
	163	return p;
	164	}
	165
	166	static void *mfd_assert_mmap_private(int fd)
	167	{
	168	void *p;
	169
	170	p = mmap(NULL,
	171	MFD_DEF_SIZE,
	172	PROT_READ,
	173	MAP_PRIVATE,
	174	fd,
	175	0);
	176	if (p == MAP_FAILED) {
	177	printf("mmap() failed: %m\n");
	178	abort();
179	}
180
181	return p;
182	}
183
184	static int mfd_assert_open(int fd, int flags, mode_t mode)
185	{
186	char buf[512];
187	int r;
188
189	sprintf(buf, "/proc/self/fd/%d", fd);
190	r = open(buf, flags, mode);
191	if (r < 0) {
192	printf("open(%s) failed: %m\n", buf);
193	abort();
194	}
195
196	return r;
197	}
198
199	static void mfd_fail_open(int fd, int flags, mode_t mode)
200	{
201	char buf[512];
202	int r;
203
204	sprintf(buf, "/proc/self/fd/%d", fd);
205	r = open(buf, flags, mode);
206	if (r >= 0) {
2ed36928	207	printf("open(%s) didn't fail as expected\n", buf);
4f5ce5e8 DH	208	abort();
	209	}
	210	}
	211
	212	static void mfd_assert_read(int fd)
	213	{
	214	char buf[16];
	215	void *p;
	216	ssize_t l;
	217
	218	l = read(fd, buf, sizeof(buf));
	219	if (l != sizeof(buf)) {
	220	printf("read() failed: %m\n");
	221	abort();
	222	}
	223
	224	/* verify PROT_READ is allowed */
	225	p = mmap(NULL,
	226	MFD_DEF_SIZE,
	227	PROT_READ,
	228	MAP_PRIVATE,
	229	fd,
	230	0);
	231	if (p == MAP_FAILED) {
	232	printf("mmap() failed: %m\n");
	233	abort();
	234	}
	235	munmap(p, MFD_DEF_SIZE);
	236
	237	/* verify MAP_PRIVATE is always allowed (even writable) */
	238	p = mmap(NULL,
	239	MFD_DEF_SIZE,
	240	PROT_READ \| PROT_WRITE,
	241	MAP_PRIVATE,
	242	fd,
	243	0);
	244	if (p == MAP_FAILED) {
	245	printf("mmap() failed: %m\n");
	246	abort();
	247	}
	248	munmap(p, MFD_DEF_SIZE);
	249	}
	250
	251	static void mfd_assert_write(int fd)
	252	{
	253	ssize_t l;
	254	void *p;
	255	int r;
	256
	257	/* verify write() succeeds */
	258	l = write(fd, "\0\0\0\0", 4);
	259	if (l != 4) {
	260	printf("write() failed: %m\n");
	261	abort();
	262	}
	263
	264	/* verify PROT_READ \| PROT_WRITE is allowed */
	265	p = mmap(NULL,
	266	MFD_DEF_SIZE,
	267	PROT_READ \| PROT_WRITE,
	268	MAP_SHARED,
	269	fd,
	270	0);
	271	if (p == MAP_FAILED) {
272	printf("mmap() failed: %m\n");
273	abort();
274	}
275	(char )p = 0;
276	munmap(p, MFD_DEF_SIZE);
277
278	/* verify PROT_WRITE is allowed */
279	p = mmap(NULL,
280	MFD_DEF_SIZE,
281	PROT_WRITE,
282	MAP_SHARED,
283	fd,
284	0);
285	if (p == MAP_FAILED) {
286	printf("mmap() failed: %m\n");
287	abort();
288	}
289	(char )p = 0;
290	munmap(p, MFD_DEF_SIZE);
291
292	/* verify PROT_READ with MAP_SHARED is allowed and a following
293	* mprotect(PROT_WRITE) allows writing */
294	p = mmap(NULL,
295	MFD_DEF_SIZE,
296	PROT_READ,
297	MAP_SHARED,
298	fd,
299	0);
300	if (p == MAP_FAILED) {
301	printf("mmap() failed: %m\n");
302	abort();
303	}
304
305	r = mprotect(p, MFD_DEF_SIZE, PROT_READ \| PROT_WRITE);
306	if (r < 0) {
307	printf("mprotect() failed: %m\n");
308	abort();
309	}
310
311	(char )p = 0;
312	munmap(p, MFD_DEF_SIZE);
313
314	/* verify PUNCH_HOLE works */
315	r = fallocate(fd,
316	FALLOC_FL_PUNCH_HOLE \| FALLOC_FL_KEEP_SIZE,
317	0,
318	MFD_DEF_SIZE);
319	if (r < 0) {
320	printf("fallocate(PUNCH_HOLE) failed: %m\n");
321	abort();
322	}
323	}
324
325	static void mfd_fail_write(int fd)
326	{
327	ssize_t l;
328	void *p;
329	int r;
330
331	/* verify write() fails */
332	l = write(fd, "data", 4);
333	if (l != -EPERM) {
334	printf("expected EPERM on write(), but got %d: %m\n", (int)l);
335	abort();
336	}
337
338	/* verify PROT_READ \| PROT_WRITE is not allowed */
339	p = mmap(NULL,
340	MFD_DEF_SIZE,
341	PROT_READ \| PROT_WRITE,
342	MAP_SHARED,
343	fd,
344	0);
345	if (p != MAP_FAILED) {
346	printf("mmap() didn't fail as expected\n");
347	abort();
348	}
349
350	/* verify PROT_WRITE is not allowed */
351	p = mmap(NULL,
352	MFD_DEF_SIZE,
353	PROT_WRITE,
354	MAP_SHARED,
355	fd,
356	0);
357	if (p != MAP_FAILED) {
358	printf("mmap() didn't fail as expected\n");
359	abort();
360	}
361
362	/* Verify PROT_READ with MAP_SHARED with a following mprotect is not
363	* allowed. Note that for r/w the kernel already prevents the mmap. */
364	p = mmap(NULL,
365	MFD_DEF_SIZE,
366	PROT_READ,
367	MAP_SHARED,
368	fd,
369	0);
370	if (p != MAP_FAILED) {
371	r = mprotect(p, MFD_DEF_SIZE, PROT_READ \| PROT_WRITE);
372	if (r >= 0) {
373	printf("mmap()+mprotect() didn't fail as expected\n");
374	abort();
375	}
376	}
377
378	/* verify PUNCH_HOLE fails */
379	r = fallocate(fd,
380	FALLOC_FL_PUNCH_HOLE \| FALLOC_FL_KEEP_SIZE,
381	0,
382	MFD_DEF_SIZE);
383	if (r >= 0) {
384	printf("fallocate(PUNCH_HOLE) didn't fail as expected\n");
385	abort();
386	}
387	}
388
389	static void mfd_assert_shrink(int fd)
390	{
391	int r, fd2;
392
393	r = ftruncate(fd, MFD_DEF_SIZE / 2);
394	if (r < 0) {
395	printf("ftruncate(SHRINK) failed: %m\n");
396	abort();
397	}
398
399	mfd_assert_size(fd, MFD_DEF_SIZE / 2);
400
401	fd2 = mfd_assert_open(fd,
402	O_RDWR \| O_CREAT \| O_TRUNC,
403	S_IRUSR \| S_IWUSR);
404	close(fd2);
405
406	mfd_assert_size(fd, 0);
407	}
408
409	static void mfd_fail_shrink(int fd)
410	{
411	int r;
412
413	r = ftruncate(fd, MFD_DEF_SIZE / 2);
414	if (r >= 0) {
415	printf("ftruncate(SHRINK) didn't fail as expected\n");
416	abort();
417	}
418
419	mfd_fail_open(fd,
420	O_RDWR \| O_CREAT \| O_TRUNC,
421	S_IRUSR \| S_IWUSR);
422	}
423
424	static void mfd_assert_grow(int fd)
425	{
426	int r;
427
428	r = ftruncate(fd, MFD_DEF_SIZE * 2);
429	if (r < 0) {
430	printf("ftruncate(GROW) failed: %m\n");
431	abort();
432	}
433
434	mfd_assert_size(fd, MFD_DEF_SIZE * 2);
435
436	r = fallocate(fd,
437	0,
438	0,
439	MFD_DEF_SIZE * 4);
440	if (r < 0) {
441	printf("fallocate(ALLOC) failed: %m\n");
442	abort();
443	}
444
445	mfd_assert_size(fd, MFD_DEF_SIZE * 4);
446	}
447
448	static void mfd_fail_grow(int fd)
449	{
450	int r;
451
452	r = ftruncate(fd, MFD_DEF_SIZE * 2);
453	if (r >= 0) {
454	printf("ftruncate(GROW) didn't fail as expected\n");
455	abort();
456	}
457
458	r = fallocate(fd,
459	0,
460	0,
461	MFD_DEF_SIZE * 4);
462	if (r >= 0) {
463	printf("fallocate(ALLOC) didn't fail as expected\n");
464	abort();
465	}
466	}
467
468	static void mfd_assert_grow_write(int fd)
469	{
470	static char buf[MFD_DEF_SIZE * 8];
471	ssize_t l;
472
473	l = pwrite(fd, buf, sizeof(buf), 0);
474	if (l != sizeof(buf)) {
475	printf("pwrite() failed: %m\n");
476	abort();
477	}
478
479	mfd_assert_size(fd, MFD_DEF_SIZE * 8);
480	}
481
482	static void mfd_fail_grow_write(int fd)
483	{
484	static char buf[MFD_DEF_SIZE * 8];
485	ssize_t l;
486
487	l = pwrite(fd, buf, sizeof(buf), 0);
488	if (l == sizeof(buf)) {
489	printf("pwrite() didn't fail as expected\n");
490	abort();
491	}
492	}
493
494	static int idle_thread_fn(void *arg)
495	{
496	sigset_t set;
497	int sig;
498
499	/* dummy waiter; SIGTERM terminates us anyway */
500	sigemptyset(&set);
501	sigaddset(&set, SIGTERM);
502	sigwait(&set, &sig);
503
504	return 0;
505	}
506
507	static pid_t spawn_idle_thread(unsigned int flags)
508	{
509	uint8_t *stack;
510	pid_t pid;
511
512	stack = malloc(STACK_SIZE);
513	if (!stack) {
514	printf("malloc(STACK_SIZE) failed: %m\n");
515	abort();
516	}
517
518	pid = clone(idle_thread_fn,
519	stack + STACK_SIZE,
520	SIGCHLD \| flags,
521	NULL);
522	if (pid < 0) {
523	printf("clone() failed: %m\n");
524	abort();
525	}
526
527	return pid;
528	}
529
530	static void join_idle_thread(pid_t pid)
531	{
532	kill(pid, SIGTERM);
533	waitpid(pid, NULL, 0);
534	}
535
536	/*
537	* Test memfd_create() syscall
538	* Verify syscall-argument validation, including name checks, flag validation
539	* and more.
540	*/
541	static void test_create(void)
542	{
543	char buf[2048];
544	int fd;
545
546	/* test NULL name */
547	mfd_fail_new(NULL, 0);
548
549	/* test over-long name (not zero-terminated) */
550	memset(buf, 0xff, sizeof(buf));
551	mfd_fail_new(buf, 0);
552
553	/* test over-long zero-terminated name */
554	memset(buf, 0xff, sizeof(buf));
555	buf[sizeof(buf) - 1] = 0;
556	mfd_fail_new(buf, 0);
557
558	/* verify "" is a valid name */
559	fd = mfd_assert_new("", 0, 0);
560	close(fd);
561
562	/* verify invalid O_* open flags */
563	mfd_fail_new("", 0x0100);
564	mfd_fail_new("", ~MFD_CLOEXEC);
565	mfd_fail_new("", ~MFD_ALLOW_SEALING);
566	mfd_fail_new("", ~0);
567	mfd_fail_new("", 0x80000000U);
568
569	/* verify MFD_CLOEXEC is allowed */
570	fd = mfd_assert_new("", 0, MFD_CLOEXEC);
571	close(fd);
572
573	/* verify MFD_ALLOW_SEALING is allowed */
574	fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING);
575	close(fd);
576
577	/* verify MFD_ALLOW_SEALING \| MFD_CLOEXEC is allowed */
578	fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING \| MFD_CLOEXEC);
579	close(fd);
580	}
581
582	/*
583	* Test basic sealing
584	* A very basic sealing test to see whether setting/retrieving seals works.
585	*/
586	static void test_basic(void)
587	{
588	int fd;
589
590	fd = mfd_assert_new("kern_memfd_basic",
591	MFD_DEF_SIZE,
592	MFD_CLOEXEC \| MFD_ALLOW_SEALING);
593
594	/* add basic seals */
595	mfd_assert_has_seals(fd, 0);
596	mfd_assert_add_seals(fd, F_SEAL_SHRINK \|
597	F_SEAL_WRITE);
598	mfd_assert_has_seals(fd, F_SEAL_SHRINK \|
599	F_SEAL_WRITE);
600
601	/* add them again */
602	mfd_assert_add_seals(fd, F_SEAL_SHRINK \|
603	F_SEAL_WRITE);
604	mfd_assert_has_seals(fd, F_SEAL_SHRINK \|
605	F_SEAL_WRITE);
606
607	/* add more seals and seal against sealing */
608	mfd_assert_add_seals(fd, F_SEAL_GROW \| F_SEAL_SEAL);
609	mfd_assert_has_seals(fd, F_SEAL_SHRINK \|
610	F_SEAL_GROW \|
611	F_SEAL_WRITE \|
612	F_SEAL_SEAL);
613
614	/* verify that sealing no longer works */
615	mfd_fail_add_seals(fd, F_SEAL_GROW);
616	mfd_fail_add_seals(fd, 0);
617
618	close(fd);
619
620	/* verify sealing does not work without MFD_ALLOW_SEALING */
621	fd = mfd_assert_new("kern_memfd_basic",
622	MFD_DEF_SIZE,
623	MFD_CLOEXEC);
624	mfd_assert_has_seals(fd, F_SEAL_SEAL);
625	mfd_fail_add_seals(fd, F_SEAL_SHRINK \|
626	F_SEAL_GROW \|
627	F_SEAL_WRITE);
628	mfd_assert_has_seals(fd, F_SEAL_SEAL);
629	close(fd);
630	}
631
632	/*
633	* Test SEAL_WRITE
634	* Test whether SEAL_WRITE actually prevents modifications.
635	*/
636	static void test_seal_write(void)
637	{
638	int fd;
639
640	fd = mfd_assert_new("kern_memfd_seal_write",
641	MFD_DEF_SIZE,
642	MFD_CLOEXEC \| MFD_ALLOW_SEALING);
643	mfd_assert_has_seals(fd, 0);
644	mfd_assert_add_seals(fd, F_SEAL_WRITE);
645	mfd_assert_has_seals(fd, F_SEAL_WRITE);
646
647	mfd_assert_read(fd);
648	mfd_fail_write(fd);
649	mfd_assert_shrink(fd);
650	mfd_assert_grow(fd);
651	mfd_fail_grow_write(fd);
652
653	close(fd);
654	}
655
656	/*
657	* Test SEAL_SHRINK
658	* Test whether SEAL_SHRINK actually prevents shrinking
659	*/
660	static void test_seal_shrink(void)
661	{
662	int fd;
663
664	fd = mfd_assert_new("kern_memfd_seal_shrink",
665	MFD_DEF_SIZE,
666	MFD_CLOEXEC \| MFD_ALLOW_SEALING);
667	mfd_assert_has_seals(fd, 0);
668	mfd_assert_add_seals(fd, F_SEAL_SHRINK);
669	mfd_assert_has_seals(fd, F_SEAL_SHRINK);
670
671	mfd_assert_read(fd);
672	mfd_assert_write(fd);
673	mfd_fail_shrink(fd);
674	mfd_assert_grow(fd);
675	mfd_assert_grow_write(fd);
676
677	close(fd);
678	}
679
680	/*
681	* Test SEAL_GROW
682	* Test whether SEAL_GROW actually prevents growing
683	*/
684	static void test_seal_grow(void)
685	{
686	int fd;
687
688	fd = mfd_assert_new("kern_memfd_seal_grow",
689	MFD_DEF_SIZE,
690	MFD_CLOEXEC \| MFD_ALLOW_SEALING);
691	mfd_assert_has_seals(fd, 0);
692	mfd_assert_add_seals(fd, F_SEAL_GROW);
693	mfd_assert_has_seals(fd, F_SEAL_GROW);
694
695	mfd_assert_read(fd);
696	mfd_assert_write(fd);
697	mfd_assert_shrink(fd);
698	mfd_fail_grow(fd);
699	mfd_fail_grow_write(fd);
700
701	close(fd);
702	}
703
704	/*
705	* Test SEAL_SHRINK \| SEAL_GROW
706	* Test whether SEAL_SHRINK \| SEAL_GROW actually prevents resizing
707	*/
708	static void test_seal_resize(void)
709	{
710	int fd;
711
712	fd = mfd_assert_new("kern_memfd_seal_resize",
713	MFD_DEF_SIZE,
714	MFD_CLOEXEC \| MFD_ALLOW_SEALING);
715	mfd_assert_has_seals(fd, 0);
716	mfd_assert_add_seals(fd, F_SEAL_SHRINK \| F_SEAL_GROW);
717	mfd_assert_has_seals(fd, F_SEAL_SHRINK \| F_SEAL_GROW);
718
719	mfd_assert_read(fd);
720	mfd_assert_write(fd);
721	mfd_fail_shrink(fd);
722	mfd_fail_grow(fd);
723	mfd_fail_grow_write(fd);
724
725	close(fd);
726	}
727
728	/*
729	* Test sharing via dup()
730	* Test that seals are shared between dupped FDs and they're all equal.
731	*/
732	static void test_share_dup(void)
733	{
734	int fd, fd2;
735
736	fd = mfd_assert_new("kern_memfd_share_dup",
737	MFD_DEF_SIZE,
738	MFD_CLOEXEC \| MFD_ALLOW_SEALING);
739	mfd_assert_has_seals(fd, 0);
740
741	fd2 = mfd_assert_dup(fd);
742	mfd_assert_has_seals(fd2, 0);
743
744	mfd_assert_add_seals(fd, F_SEAL_WRITE);
745	mfd_assert_has_seals(fd, F_SEAL_WRITE);
746	mfd_assert_has_seals(fd2, F_SEAL_WRITE);
747
748	mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
749	mfd_assert_has_seals(fd, F_SEAL_WRITE \| F_SEAL_SHRINK);
750	mfd_assert_has_seals(fd2, F_SEAL_WRITE \| F_SEAL_SHRINK);
751
752	mfd_assert_add_seals(fd, F_SEAL_SEAL);
753	mfd_assert_has_seals(fd, F_SEAL_WRITE \| F_SEAL_SHRINK \| F_SEAL_SEAL);
754	mfd_assert_has_seals(fd2, F_SEAL_WRITE \| F_SEAL_SHRINK \| F_SEAL_SEAL);
755
756	mfd_fail_add_seals(fd, F_SEAL_GROW);
757	mfd_fail_add_seals(fd2, F_SEAL_GROW);
758	mfd_fail_add_seals(fd, F_SEAL_SEAL);
759	mfd_fail_add_seals(fd2, F_SEAL_SEAL);
760
761	close(fd2);
762
763	mfd_fail_add_seals(fd, F_SEAL_GROW);
764	close(fd);
765	}
766
767	/*
768	* Test sealing with active mmap()s
769	* Modifying seals is only allowed if no other mmap() refs exist.
770	*/
771	static void test_share_mmap(void)
772	{
773	int fd;
774	void *p;
775
776	fd = mfd_assert_new("kern_memfd_share_mmap",
777	MFD_DEF_SIZE,
778	MFD_CLOEXEC \| MFD_ALLOW_SEALING);
779	mfd_assert_has_seals(fd, 0);
780
781	/* shared/writable ref prevents sealing WRITE, but allows others */
782	p = mfd_assert_mmap_shared(fd);
783	mfd_fail_add_seals(fd, F_SEAL_WRITE);
784	mfd_assert_has_seals(fd, 0);
785	mfd_assert_add_seals(fd, F_SEAL_SHRINK);
786	mfd_assert_has_seals(fd, F_SEAL_SHRINK);
787	munmap(p, MFD_DEF_SIZE);
788
789	/* readable ref allows sealing */
790	p = mfd_assert_mmap_private(fd);
791	mfd_assert_add_seals(fd, F_SEAL_WRITE);
792	mfd_assert_has_seals(fd, F_SEAL_WRITE \| F_SEAL_SHRINK);
793	munmap(p, MFD_DEF_SIZE);
794
795	close(fd);
796	}
797
798	/*
799	* Test sealing with open(/proc/self/fd/%d)
800	* Via /proc we can get access to a separate file-context for the same memfd.
801	* This is not like dup(), but like a real separate open(). Make sure the
802	* semantics are as expected and we correctly check for RDONLY / WRONLY / RDWR.
803	*/
804	static void test_share_open(void)
805	{
806	int fd, fd2;
807
808	fd = mfd_assert_new("kern_memfd_share_open",
809	MFD_DEF_SIZE,
810	MFD_CLOEXEC \| MFD_ALLOW_SEALING);
811	mfd_assert_has_seals(fd, 0);
812
813	fd2 = mfd_assert_open(fd, O_RDWR, 0);
814	mfd_assert_add_seals(fd, F_SEAL_WRITE);
815	mfd_assert_has_seals(fd, F_SEAL_WRITE);
816	mfd_assert_has_seals(fd2, F_SEAL_WRITE);
817
818	mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
819	mfd_assert_has_seals(fd, F_SEAL_WRITE \| F_SEAL_SHRINK);
820	mfd_assert_has_seals(fd2, F_SEAL_WRITE \| F_SEAL_SHRINK);
821
822	close(fd);
823	fd = mfd_assert_open(fd2, O_RDONLY, 0);
824
825	mfd_fail_add_seals(fd, F_SEAL_SEAL);
826	mfd_assert_has_seals(fd, F_SEAL_WRITE \| F_SEAL_SHRINK);
827	mfd_assert_has_seals(fd2, F_SEAL_WRITE \| F_SEAL_SHRINK);
828
829	close(fd2);
830	fd2 = mfd_assert_open(fd, O_RDWR, 0);
831
832	mfd_assert_add_seals(fd2, F_SEAL_SEAL);
833	mfd_assert_has_seals(fd, F_SEAL_WRITE \| F_SEAL_SHRINK \| F_SEAL_SEAL);
834	mfd_assert_has_seals(fd2, F_SEAL_WRITE \| F_SEAL_SHRINK \| F_SEAL_SEAL);
835
836	close(fd2);
837	close(fd);
838	}
839
840	/*
841	* Test sharing via fork()
842	* Test whether seal-modifications work as expected with forked childs.
843	*/
844	static void test_share_fork(void)
845	{
846	int fd;
847	pid_t pid;
848
849	fd = mfd_assert_new("kern_memfd_share_fork",
850	MFD_DEF_SIZE,
851	MFD_CLOEXEC \| MFD_ALLOW_SEALING);
852	mfd_assert_has_seals(fd, 0);
853
854	pid = spawn_idle_thread(0);
855	mfd_assert_add_seals(fd, F_SEAL_SEAL);
856	mfd_assert_has_seals(fd, F_SEAL_SEAL);
857
858	mfd_fail_add_seals(fd, F_SEAL_WRITE);
859	mfd_assert_has_seals(fd, F_SEAL_SEAL);
860
861	join_idle_thread(pid);
862
863	mfd_fail_add_seals(fd, F_SEAL_WRITE);
864	mfd_assert_has_seals(fd, F_SEAL_SEAL);
865
866	close(fd);
867	}
868
869	int main(int argc, char **argv)
870	{
871	pid_t pid;
872
873	printf("memfd: CREATE\n");
874	test_create();
875	printf("memfd: BASIC\n");
876	test_basic();
877
878	printf("memfd: SEAL-WRITE\n");
879	test_seal_write();
880	printf("memfd: SEAL-SHRINK\n");
881	test_seal_shrink();
882	printf("memfd: SEAL-GROW\n");
883	test_seal_grow();
884	printf("memfd: SEAL-RESIZE\n");
885	test_seal_resize();
886
887	printf("memfd: SHARE-DUP\n");
888	test_share_dup();
889	printf("memfd: SHARE-MMAP\n");
890	test_share_mmap();
891	printf("memfd: SHARE-OPEN\n");
892	test_share_open();
893	printf("memfd: SHARE-FORK\n");
894	test_share_fork();
895
896	/* Run test-suite in a multi-threaded environment with a shared
897	* file-table. */
898	pid = spawn_idle_thread(CLONE_FILES \| CLONE_FS \| CLONE_VM);
899	printf("memfd: SHARE-DUP (shared file-table)\n");
900	test_share_dup();
901	printf("memfd: SHARE-MMAP (shared file-table)\n");
902	test_share_mmap();
903	printf("memfd: SHARE-OPEN (shared file-table)\n");
904	test_share_open();
905	printf("memfd: SHARE-FORK (shared file-table)\n");
906	test_share_fork();
907	join_idle_thread(pid);
908
909	printf("memfd: DONE\n");
910
911	return 0;
912	}