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Commit 4f5ce5e8 authored by David Herrmann's avatar David Herrmann Committed by Linus Torvalds
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selftests: add memfd_create() + sealing tests 



Some basic tests to verify sealing on memfds works as expected and
guarantees the advertised semantics.

Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Acked-by: default avatarHugh Dickins <hughd@google.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Ryan Lortie <desrt@desrt.ca>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Daniel Mack <zonque@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9183df25

tools/testing/selftests/Makefile

+1 −0
Original line number Original line Diff line number Diff line
@@ -2,6 +2,7 @@ TARGETS = breakpoints 
TARGETS += cpu-hotplug

TARGETS += cpu-hotplug

TARGETS += efivarfs

TARGETS += efivarfs

TARGETS += kcmp

TARGETS += kcmp

TARGETS += memfd

TARGETS += memory-hotplug

TARGETS += memory-hotplug

TARGETS += mqueue

TARGETS += mqueue

TARGETS += net

TARGETS += net

tools/testing/selftests/memfd/.gitignore

0 → 100644
+2 −0
Original line number Original line Diff line number Diff line 
memfd_test

memfd-test-file

tools/testing/selftests/memfd/Makefile

0 → 100644
+29 −0
Original line number Original line Diff line number Diff line 
uname_M := $(shell uname -m 2>/dev/null || echo not)

ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/i386/)

ifeq ($(ARCH),i386)

	ARCH := X86

endif

ifeq ($(ARCH),x86_64)

	ARCH := X86

endif



CFLAGS += -I../../../../arch/x86/include/generated/uapi/

CFLAGS += -I../../../../arch/x86/include/uapi/

CFLAGS += -I../../../../include/uapi/

CFLAGS += -I../../../../include/



all:

ifeq ($(ARCH),X86)

	gcc $(CFLAGS) memfd_test.c -o memfd_test

else

	echo "Not an x86 target, can't build memfd selftest"

endif



run_tests: all

ifeq ($(ARCH),X86)

	gcc $(CFLAGS) memfd_test.c -o memfd_test

endif

	@./memfd_test || echo "memfd_test: [FAIL]"



clean:

	$(RM) memfd_test

tools/testing/selftests/memfd/memfd_test.c

0 → 100644
+913 −0
Original line number Original line Diff line number Diff line 
#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 <unistd.h>



#define MFD_DEF_SIZE 8192

#define STACK_SIZE 65535



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 __u64 mfd_assert_get_seals(int fd)

{

	long r;



	r = fcntl(fd, F_GET_SEALS);

	if (r < 0) {

		printf("GET_SEALS(%d) failed: %m\n", fd);

		abort();

	}



	return r;

}



static void mfd_assert_has_seals(int fd, __u64 seals)

{

	__u64 s;



	s = mfd_assert_get_seals(fd);

	if (s != seals) {

		printf("%llu != %llu = GET_SEALS(%d)\n",

		       (unsigned long long)seals, (unsigned long long)s, fd);

		abort();

	}

}



static void mfd_assert_add_seals(int fd, __u64 seals)

{

	long r;

	__u64 s;



	s = mfd_assert_get_seals(fd);

	r = fcntl(fd, F_ADD_SEALS, seals);

	if (r < 0) {

		printf("ADD_SEALS(%d, %llu -> %llu) failed: %m\n",

		       fd, (unsigned long long)s, (unsigned long long)seals);

		abort();

	}

}



static void mfd_fail_add_seals(int fd, __u64 seals)

{

	long r;

	__u64 s;



	r = fcntl(fd, F_GET_SEALS);

	if (r < 0)

		s = 0;

	else

		s = r;



	r = fcntl(fd, F_ADD_SEALS, seals);

	if (r >= 0) {

		printf("ADD_SEALS(%d, %llu -> %llu) didn't fail as expected\n",

		       fd, (unsigned long long)s, (unsigned long long)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");

		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;

}