diff options
Diffstat (limited to 'tools/testing/selftests/memfd/memfd_test.c')
| -rw-r--r-- | tools/testing/selftests/memfd/memfd_test.c | 1080 |
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; +} |