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-rw-r--r--tools/testing/selftests/memfd/memfd_test.c1080
1 files changed, 1080 insertions, 0 deletions
diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c
new file mode 100644
index 000000000..fba322d1c
--- /dev/null
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -0,0 +1,1080 @@
+// 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 <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>
+
+#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
+
+/*
+ * Default is not to test hugetlbfs
+ */
+static size_t mfd_def_size = MFD_DEF_SIZE;
+static const char *memfd_str = MEMFD_STR;
+
+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 int mfd_assert_reopen_fd(int fd_in)
+{
+ int r, 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)
+{
+ 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);
+}
+
+/* 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 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;
+
+ 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 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 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 childs.
+ */
+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_seal_write();
+ test_seal_future_write();
+ test_seal_shrink();
+ test_seal_grow();
+ test_seal_resize();
+
+ 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;
+}