// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#define __EXPORTED_HEADERS__
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <linux/falloc.h>
#include <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>
#include <ctype.h>
#include "common.h"
#define MEMFD_STR "memfd:"
#define MEMFD_HUGE_STR "memfd-hugetlb:"
#define SHARED_FT_STR "(shared file-table)"
#define MFD_DEF_SIZE 8192
#define STACK_SIZE 65536
#define F_SEAL_EXEC 0x0020
#define F_WX_SEALS (F_SEAL_SHRINK | \
F_SEAL_GROW | \
F_SEAL_WRITE | \
F_SEAL_FUTURE_WRITE | \
F_SEAL_EXEC)
#define MFD_NOEXEC_SEAL 0x0008U
/*
* Default is not to test hugetlbfs
*/
static size_t mfd_def_size = MFD_DEF_SIZE;
static const char *memfd_str = MEMFD_STR;
static ssize_t fd2name(int fd, char *buf, size_t bufsize)
{
char buf1[PATH_MAX];
int size;
ssize_t nbytes;
size = snprintf(buf1, PATH_MAX, "/proc/self/fd/%d", fd);
if (size < 0) {
printf("snprintf(%d) failed on %m\n", fd);
abort();
}
/*
* reserver one byte for string termination.
*/
nbytes = readlink(buf1, buf, bufsize-1);
if (nbytes == -1) {
printf("readlink(%s) failed %m\n", buf1);
abort();
}
buf[nbytes] = '\0';
return nbytes;
}
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 sysctl_assert_write(const char *val)
{
int fd = open("/proc/sys/vm/memfd_noexec", O_WRONLY | O_CLOEXEC);
if (fd < 0) {
printf("open sysctl failed: %m\n");
abort();
}
if (write(fd, val, strlen(val)) < 0) {
printf("write sysctl %s failed: %m\n", val);
abort();
}
}
static void sysctl_fail_write(const char *val)
{
int fd = open("/proc/sys/vm/memfd_noexec", O_WRONLY | O_CLOEXEC);
if (fd < 0) {
printf("open sysctl failed: %m\n");
abort();
}
if (write(fd, val, strlen(val)) >= 0) {
printf("write sysctl %s succeeded, but failure expected\n",
val);
abort();
}
}
static void sysctl_assert_equal(const char *val)
{
char *p, buf[128] = {};
int fd = open("/proc/sys/vm/memfd_noexec", O_RDONLY | O_CLOEXEC);
if (fd < 0) {
printf("open sysctl failed: %m\n");
abort();
}
if (read(fd, buf, sizeof(buf)) < 0) {
printf("read sysctl failed: %m\n");
abort();
}
/* Strip trailing whitespace. */
p = buf;
while (!isspace(*p))
p++;
*p = '\0';
if (strcmp(buf, val) != 0) {
printf("unexpected sysctl value: expected %s, got %s\n", val, buf);
abort();
}
}
static int mfd_assert_reopen_fd(int fd_in)
{
int fd;
char path[100];
sprintf(path, "/proc/self/fd/%d", fd_in);
fd = open(path, O_RDWR);
if (fd < 0) {
printf("re-open of existing fd %d failed\n", fd_in);
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)
{
char buf[PATH_MAX];
unsigned int s;
fd2name(fd, buf, PATH_MAX);
s = mfd_assert_get_seals(fd);
if (s != seals) {
printf("%u != %u = GET_SEALS(%s)\n", seals, s, buf);
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);
}
/* Test that PROT_READ + MAP_SHARED mappings work. */
static void mfd_assert_read_shared(int fd)
{
void *p;
/* verify PROT_READ and MAP_SHARED *is* allowed */
p = mmap(NULL,
mfd_def_size,
PROT_READ,
MAP_SHARED,
fd,
0);
if (p == MAP_FAILED) {
printf("mmap() failed: %m\n");
abort();
}
munmap(p, mfd_def_size);
}
static void mfd_assert_fork_private_write(int fd)
{
int *p;
pid_t pid;
p = mmap(NULL,
mfd_def_size,
PROT_READ | PROT_WRITE,
MAP_PRIVATE,
fd,
0);
if (p == MAP_FAILED) {
printf("mmap() failed: %m\n");
abort();
}
p[0] = 22;
pid = fork();
if (pid == 0) {
p[0] = 33;
exit(0);
} else {
waitpid(pid, NULL, 0);
if (p[0] != 22) {
printf("MAP_PRIVATE copy-on-write failed: %m\n");
abort();
}
}
munmap(p, mfd_def_size);
}
static void mfd_assert_write(int fd)
{
ssize_t l;
void *p;
int r;
/*
* huegtlbfs does not support write, but we want to
* verify everything else here.
*/
if (!hugetlbfs_test) {
/* 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();
}
munmap(p, mfd_def_size);
}
/* 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;
ssize_t l;
/* hugetlbfs does not support write */
if (hugetlbfs_test)
return;
buf = malloc(mfd_def_size * 8);
if (!buf) {
printf("malloc(%zu) failed: %m\n", mfd_def_size * 8);
abort();
}
l = pwrite(fd, buf, mfd_def_size * 8, 0);
if (l != (mfd_def_size * 8)) {
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;
ssize_t l;
/* hugetlbfs does not support write */
if (hugetlbfs_test)
return;
buf = malloc(mfd_def_size * 8);
if (!buf) {
printf("malloc(%zu) failed: %m\n", mfd_def_size * 8);
abort();
}
l = pwrite(fd, buf, mfd_def_size * 8, 0);
if (l == (mfd_def_size * 8)) {
printf("pwrite() didn't fail as expected\n");
abort();
}
}
static void mfd_assert_mode(int fd, int mode)
{
struct stat st;
char buf[PATH_MAX];
fd2name(fd, buf, PATH_MAX);
if (fstat(fd, &st) < 0) {
printf("fstat(%s) failed: %m\n", buf);
abort();
}
if ((st.st_mode & 07777) != mode) {
printf("fstat(%s) wrong file mode 0%04o, but expected 0%04o\n",
buf, (int)st.st_mode & 07777, mode);
abort();
}
}
static void mfd_assert_chmod(int fd, int mode)
{
char buf[PATH_MAX];
fd2name(fd, buf, PATH_MAX);
if (fchmod(fd, mode) < 0) {
printf("fchmod(%s, 0%04o) failed: %m\n", buf, mode);
abort();
}
mfd_assert_mode(fd, mode);
}
static void mfd_fail_chmod(int fd, int mode)
{
struct stat st;
char buf[PATH_MAX];
fd2name(fd, buf, PATH_MAX);
if (fstat(fd, &st) < 0) {
printf("fstat(%s) failed: %m\n", buf);
abort();
}
if (fchmod(fd, mode) == 0) {
printf("fchmod(%s, 0%04o) didn't fail as expected\n",
buf, mode);
abort();
}
/* verify that file mode bits did not change */
mfd_assert_mode(fd, st.st_mode & 07777);
}
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_thread(unsigned int flags, int (*fn)(void *), void *arg)
{
uint8_t *stack;
pid_t pid;
stack = malloc(STACK_SIZE);
if (!stack) {
printf("malloc(STACK_SIZE) failed: %m\n");
abort();
}
pid = clone(fn, stack + STACK_SIZE, SIGCHLD | flags, arg);
if (pid < 0) {
printf("clone() failed: %m\n");
abort();
}
return pid;
}
static void join_thread(pid_t pid)
{
int wstatus;
if (waitpid(pid, &wstatus, 0) < 0) {
printf("newpid thread: waitpid() failed: %m\n");
abort();
}
if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) != 0) {
printf("newpid thread: exited with non-zero error code %d\n",
WEXITSTATUS(wstatus));
abort();
}
if (WIFSIGNALED(wstatus)) {
printf("newpid thread: killed by signal %d\n",
WTERMSIG(wstatus));
abort();
}
}
static pid_t spawn_idle_thread(unsigned int flags)
{
return spawn_thread(flags, idle_thread_fn, NULL);
}
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;
printf("%s CREATE\n", memfd_str);
/* 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 EXEC and NOEXEC_SEAL can't both be set */
mfd_fail_new("", MFD_EXEC | MFD_NOEXEC_SEAL);
/* 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;
printf("%s BASIC\n", memfd_str);
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;
printf("%s SEAL-WRITE\n", memfd_str);
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_FUTURE_WRITE
* Test whether SEAL_FUTURE_WRITE actually prevents modifications.
*/
static void test_seal_future_write(void)
{
int fd, fd2;
void *p;
printf("%s SEAL-FUTURE-WRITE\n", memfd_str);
fd = mfd_assert_new("kern_memfd_seal_future_write",
mfd_def_size,
MFD_CLOEXEC | MFD_ALLOW_SEALING);
p = mfd_assert_mmap_shared(fd);
mfd_assert_has_seals(fd, 0);
mfd_assert_add_seals(fd, F_SEAL_FUTURE_WRITE);
mfd_assert_has_seals(fd, F_SEAL_FUTURE_WRITE);
/* read should pass, writes should fail */
mfd_assert_read(fd);
mfd_assert_read_shared(fd);
mfd_fail_write(fd);
fd2 = mfd_assert_reopen_fd(fd);
/* read should pass, writes should still fail */
mfd_assert_read(fd2);
mfd_assert_read_shared(fd2);
mfd_fail_write(fd2);
mfd_assert_fork_private_write(fd);
munmap(p, mfd_def_size);
close(fd2);
close(fd);
}
/*
* Test SEAL_SHRINK
* Test whether SEAL_SHRINK actually prevents shrinking
*/
static void test_seal_shrink(void)
{
int fd;
printf("%s SEAL-SHRINK\n", memfd_str);
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;
printf("%s SEAL-GROW\n", memfd_str);
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;
printf("%s SEAL-RESIZE\n", memfd_str);
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 SEAL_EXEC
* Test fd is created with exec and allow sealing.
* chmod() cannot change x bits after sealing.
*/
static void test_exec_seal(void)
{
int fd;
printf("%s SEAL-EXEC\n", memfd_str);
printf("%s Apply SEAL_EXEC\n", memfd_str);
fd = mfd_assert_new("kern_memfd_seal_exec",
mfd_def_size,
MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_EXEC);
mfd_assert_mode(fd, 0777);
mfd_assert_chmod(fd, 0644);
mfd_assert_has_seals(fd, 0);
mfd_assert_add_seals(fd, F_SEAL_EXEC);
mfd_assert_has_seals(fd, F_SEAL_EXEC);
mfd_assert_chmod(fd, 0600);
mfd_fail_chmod(fd, 0777);
mfd_fail_chmod(fd, 0670);
mfd_fail_chmod(fd, 0605);
mfd_fail_chmod(fd, 0700);
mfd_fail_chmod(fd, 0100);
mfd_assert_chmod(fd, 0666);
mfd_assert_write(fd);
close(fd);
printf("%s Apply ALL_SEALS\n", memfd_str);
fd = mfd_assert_new("kern_memfd_seal_exec",
mfd_def_size,
MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_EXEC);
mfd_assert_mode(fd, 0777);
mfd_assert_chmod(fd, 0700);
mfd_assert_has_seals(fd, 0);
mfd_assert_add_seals(fd, F_SEAL_EXEC);
mfd_assert_has_seals(fd, F_WX_SEALS);
mfd_fail_chmod(fd, 0711);
mfd_fail_chmod(fd, 0600);
mfd_fail_write(fd);
close(fd);
}
/*
* Test EXEC_NO_SEAL
* Test fd is created with exec and not allow sealing.
*/
static void test_exec_no_seal(void)
{
int fd;
printf("%s EXEC_NO_SEAL\n", memfd_str);
/* Create with EXEC but without ALLOW_SEALING */
fd = mfd_assert_new("kern_memfd_exec_no_sealing",
mfd_def_size,
MFD_CLOEXEC | MFD_EXEC);
mfd_assert_mode(fd, 0777);
mfd_assert_has_seals(fd, F_SEAL_SEAL);
mfd_assert_chmod(fd, 0666);
close(fd);
}
/*
* Test memfd_create with MFD_NOEXEC flag
*/
static void test_noexec_seal(void)
{
int fd;
printf("%s NOEXEC_SEAL\n", memfd_str);
/* Create with NOEXEC and ALLOW_SEALING */
fd = mfd_assert_new("kern_memfd_noexec",
mfd_def_size,
MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_NOEXEC_SEAL);
mfd_assert_mode(fd, 0666);
mfd_assert_has_seals(fd, F_SEAL_EXEC);
mfd_fail_chmod(fd, 0777);
close(fd);
/* Create with NOEXEC but without ALLOW_SEALING */
fd = mfd_assert_new("kern_memfd_noexec",
mfd_def_size,
MFD_CLOEXEC | MFD_NOEXEC_SEAL);
mfd_assert_mode(fd, 0666);
mfd_assert_has_seals(fd, F_SEAL_EXEC);
mfd_fail_chmod(fd, 0777);
close(fd);
}
static void test_sysctl_sysctl0(void)
{
int fd;
sysctl_assert_equal("0");
fd = mfd_assert_new("kern_memfd_sysctl_0_dfl",
mfd_def_size,
MFD_CLOEXEC | MFD_ALLOW_SEALING);
mfd_assert_mode(fd, 0777);
mfd_assert_has_seals(fd, 0);
mfd_assert_chmod(fd, 0644);
close(fd);
}
static void test_sysctl_set_sysctl0(void)
{
sysctl_assert_write("0");
test_sysctl_sysctl0();
}
static void test_sysctl_sysctl1(void)
{
int fd;
sysctl_assert_equal("1");
fd = mfd_assert_new("kern_memfd_sysctl_1_dfl",
mfd_def_size,
MFD_CLOEXEC | MFD_ALLOW_SEALING);
mfd_assert_mode(fd, 0666);
mfd_assert_has_seals(fd, F_SEAL_EXEC);
mfd_fail_chmod(fd, 0777);
close(fd);
fd = mfd_assert_new("kern_memfd_sysctl_1_exec",
mfd_def_size,
MFD_CLOEXEC | MFD_EXEC | MFD_ALLOW_SEALING);
mfd_assert_mode(fd, 0777);
mfd_assert_has_seals(fd, 0);
mfd_assert_chmod(fd, 0644);
close(fd);
fd = mfd_assert_new("kern_memfd_sysctl_1_noexec",
mfd_def_size,
MFD_CLOEXEC | MFD_NOEXEC_SEAL | MFD_ALLOW_SEALING);
mfd_assert_mode(fd, 0666);
mfd_assert_has_seals(fd, F_SEAL_EXEC);
mfd_fail_chmod(fd, 0777);
close(fd);
}
static void test_sysctl_set_sysctl1(void)
{
sysctl_assert_write("1");
test_sysctl_sysctl1();
}
static void test_sysctl_sysctl2(void)
{
int fd;
sysctl_assert_equal("2");
fd = mfd_assert_new("kern_memfd_sysctl_2_dfl",
mfd_def_size,
MFD_CLOEXEC | MFD_ALLOW_SEALING);
mfd_assert_mode(fd, 0666);
mfd_assert_has_seals(fd, F_SEAL_EXEC);
mfd_fail_chmod(fd, 0777);
close(fd);
mfd_fail_new("kern_memfd_sysctl_2_exec",
MFD_CLOEXEC | MFD_EXEC | MFD_ALLOW_SEALING);
fd = mfd_assert_new("kern_memfd_sysctl_2_noexec",
mfd_def_size,
MFD_CLOEXEC | MFD_NOEXEC_SEAL | MFD_ALLOW_SEALING);
mfd_assert_mode(fd, 0666);
mfd_assert_has_seals(fd, F_SEAL_EXEC);
mfd_fail_chmod(fd, 0777);
close(fd);
}
static void test_sysctl_set_sysctl2(void)
{
sysctl_assert_write("2");
test_sysctl_sysctl2();
}
static int sysctl_simple_child(void *arg)
{
printf("%s sysctl 0\n", memfd_str);
test_sysctl_set_sysctl0();
printf("%s sysctl 1\n", memfd_str);
test_sysctl_set_sysctl1();
printf("%s sysctl 0\n", memfd_str);
test_sysctl_set_sysctl0();
printf("%s sysctl 2\n", memfd_str);
test_sysctl_set_sysctl2();
printf("%s sysctl 1\n", memfd_str);
test_sysctl_set_sysctl1();
printf("%s sysctl 0\n", memfd_str);
test_sysctl_set_sysctl0();
return 0;
}
/*
* Test sysctl
* A very basic test to make sure the core sysctl semantics work.
*/
static void test_sysctl_simple(void)
{
int pid = spawn_thread(CLONE_NEWPID, sysctl_simple_child, NULL);
join_thread(pid);
}
static int sysctl_nested(void *arg)
{
void (*fn)(void) = arg;
fn();
return 0;
}
static int sysctl_nested_wait(void *arg)
{
/* Wait for a SIGCONT. */
kill(getpid(), SIGSTOP);
return sysctl_nested(arg);
}
static void test_sysctl_sysctl1_failset(void)
{
sysctl_fail_write("0");
test_sysctl_sysctl1();
}
static void test_sysctl_sysctl2_failset(void)
{
sysctl_fail_write("1");
test_sysctl_sysctl2();
sysctl_fail_write("0");
test_sysctl_sysctl2();
}
static int sysctl_nested_child(void *arg)
{
int pid;
printf("%s nested sysctl 0\n", memfd_str);
sysctl_assert_write("0");
/* A further nested pidns works the same. */
pid = spawn_thread(CLONE_NEWPID, sysctl_simple_child, NULL);
join_thread(pid);
printf("%s nested sysctl 1\n", memfd_str);
sysctl_assert_write("1");
/* Child inherits our setting. */
pid = spawn_thread(CLONE_NEWPID, sysctl_nested, test_sysctl_sysctl1);
join_thread(pid);
/* Child cannot raise the setting. */
pid = spawn_thread(CLONE_NEWPID, sysctl_nested,
test_sysctl_sysctl1_failset);
join_thread(pid);
/* Child can lower the setting. */
pid = spawn_thread(CLONE_NEWPID, sysctl_nested,
test_sysctl_set_sysctl2);
join_thread(pid);
/* Child lowering the setting has no effect on our setting. */
test_sysctl_sysctl1();
printf("%s nested sysctl 2\n", memfd_str);
sysctl_assert_write("2");
/* Child inherits our setting. */
pid = spawn_thread(CLONE_NEWPID, sysctl_nested, test_sysctl_sysctl2);
join_thread(pid);
/* Child cannot raise the setting. */
pid = spawn_thread(CLONE_NEWPID, sysctl_nested,
test_sysctl_sysctl2_failset);
join_thread(pid);
/* Verify that the rules are actually inherited after fork. */
printf("%s nested sysctl 0 -> 1 after fork\n", memfd_str);
sysctl_assert_write("0");
pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
test_sysctl_sysctl1_failset);
sysctl_assert_write("1");
kill(pid, SIGCONT);
join_thread(pid);
printf("%s nested sysctl 0 -> 2 after fork\n", memfd_str);
sysctl_assert_write("0");
pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
test_sysctl_sysctl2_failset);
sysctl_assert_write("2");
kill(pid, SIGCONT);
join_thread(pid);
/*
* Verify that the current effective setting is saved on fork, meaning
* that the parent lowering the sysctl doesn't affect already-forked
* children.
*/
printf("%s nested sysctl 2 -> 1 after fork\n", memfd_str);
sysctl_assert_write("2");
pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
test_sysctl_sysctl2);
sysctl_assert_write("1");
kill(pid, SIGCONT);
join_thread(pid);
printf("%s nested sysctl 2 -> 0 after fork\n", memfd_str);
sysctl_assert_write("2");
pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
test_sysctl_sysctl2);
sysctl_assert_write("0");
kill(pid, SIGCONT);
join_thread(pid);
printf("%s nested sysctl 1 -> 0 after fork\n", memfd_str);
sysctl_assert_write("1");
pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
test_sysctl_sysctl1);
sysctl_assert_write("0");
kill(pid, SIGCONT);
join_thread(pid);
return 0;
}
/*
* Test sysctl with nested pid namespaces
* Make sure that the sysctl nesting semantics work correctly.
*/
static void test_sysctl_nested(void)
{
int pid = spawn_thread(CLONE_NEWPID, sysctl_nested_child, NULL);
join_thread(pid);
}
/*
* Test sharing via dup()
* Test that seals are shared between dupped FDs and they're all equal.
*/
static void test_share_dup(char *banner, char *b_suffix)
{
int fd, fd2;
printf("%s %s %s\n", memfd_str, banner, b_suffix);
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(char *banner, char *b_suffix)
{
int fd;
void *p;
printf("%s %s %s\n", memfd_str, banner, b_suffix);
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(char *banner, char *b_suffix)
{
int fd, fd2;
printf("%s %s %s\n", memfd_str, banner, b_suffix);
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 children.
*/
static void test_share_fork(char *banner, char *b_suffix)
{
int fd;
pid_t pid;
printf("%s %s %s\n", memfd_str, banner, b_suffix);
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;
if (argc == 2) {
if (!strcmp(argv[1], "hugetlbfs")) {
unsigned long hpage_size = default_huge_page_size();
if (!hpage_size) {
printf("Unable to determine huge page size\n");
abort();
}
hugetlbfs_test = 1;
memfd_str = MEMFD_HUGE_STR;
mfd_def_size = hpage_size * 2;
} else {
printf("Unknown option: %s\n", argv[1]);
abort();
}
}
test_create();
test_basic();
test_exec_seal();
test_exec_no_seal();
test_noexec_seal();
test_seal_write();
test_seal_future_write();
test_seal_shrink();
test_seal_grow();
test_seal_resize();
test_sysctl_simple();
test_sysctl_nested();
test_share_dup("SHARE-DUP", "");
test_share_mmap("SHARE-MMAP", "");
test_share_open("SHARE-OPEN", "");
test_share_fork("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);
test_share_dup("SHARE-DUP", SHARED_FT_STR);
test_share_mmap("SHARE-MMAP", SHARED_FT_STR);
test_share_open("SHARE-OPEN", SHARED_FT_STR);
test_share_fork("SHARE-FORK", SHARED_FT_STR);
join_idle_thread(pid);
printf("memfd: DONE\n");
return 0;
}
Codebase Browser
linux