1 // SPDX-License-Identifier: GPL-2.0
2 #define _GNU_SOURCE
3 #define __EXPORTED_HEADERS__
4
5 #include <errno.h>
6 #include <inttypes.h>
7 #include <limits.h>
8 #include <linux/falloc.h>
9 #include <fcntl.h>
10 #include <linux/memfd.h>
11 #include <sched.h>
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <signal.h>
15 #include <string.h>
16 #include <sys/mman.h>
17 #include <sys/stat.h>
18 #include <sys/syscall.h>
19 #include <sys/wait.h>
20 #include <unistd.h>
21 #include <ctype.h>
22
23 #include "common.h"
24
25 #define MEMFD_STR "memfd:"
26 #define MEMFD_HUGE_STR "memfd-hugetlb:"
27 #define SHARED_FT_STR "(shared file-table)"
28
29 #define MFD_DEF_SIZE 8192
30 #define STACK_SIZE 65536
31
32 #define F_SEAL_EXEC 0x0020
33
34 #define F_WX_SEALS (F_SEAL_SHRINK | \
35 F_SEAL_GROW | \
36 F_SEAL_WRITE | \
37 F_SEAL_FUTURE_WRITE | \
38 F_SEAL_EXEC)
39
40 #define MFD_NOEXEC_SEAL 0x0008U
41
42 /*
43 * Default is not to test hugetlbfs
44 */
45 static size_t mfd_def_size = MFD_DEF_SIZE;
46 static const char *memfd_str = MEMFD_STR;
47 static int newpid_thread_fn2(void *arg);
48 static void join_newpid_thread(pid_t pid);
49
fd2name(int fd,char * buf,size_t bufsize)50 static ssize_t fd2name(int fd, char *buf, size_t bufsize)
51 {
52 char buf1[PATH_MAX];
53 int size;
54 ssize_t nbytes;
55
56 size = snprintf(buf1, PATH_MAX, "/proc/self/fd/%d", fd);
57 if (size < 0) {
58 printf("snprintf(%d) failed on %m\n", fd);
59 abort();
60 }
61
62 /*
63 * reserver one byte for string termination.
64 */
65 nbytes = readlink(buf1, buf, bufsize-1);
66 if (nbytes == -1) {
67 printf("readlink(%s) failed %m\n", buf1);
68 abort();
69 }
70 buf[nbytes] = '\0';
71 return nbytes;
72 }
73
mfd_assert_new(const char * name,loff_t sz,unsigned int flags)74 static int mfd_assert_new(const char *name, loff_t sz, unsigned int flags)
75 {
76 int r, fd;
77
78 fd = sys_memfd_create(name, flags);
79 if (fd < 0) {
80 printf("memfd_create(\"%s\", %u) failed: %m\n",
81 name, flags);
82 abort();
83 }
84
85 r = ftruncate(fd, sz);
86 if (r < 0) {
87 printf("ftruncate(%llu) failed: %m\n", (unsigned long long)sz);
88 abort();
89 }
90
91 return fd;
92 }
93
sysctl_assert_write(const char * val)94 static void sysctl_assert_write(const char *val)
95 {
96 int fd = open("/proc/sys/vm/memfd_noexec", O_WRONLY | O_CLOEXEC);
97
98 if (fd < 0) {
99 printf("open sysctl failed: %m\n");
100 abort();
101 }
102
103 if (write(fd, val, strlen(val)) < 0) {
104 printf("write sysctl %s failed: %m\n", val);
105 abort();
106 }
107 }
108
sysctl_fail_write(const char * val)109 static void sysctl_fail_write(const char *val)
110 {
111 int fd = open("/proc/sys/vm/memfd_noexec", O_WRONLY | O_CLOEXEC);
112
113 if (fd < 0) {
114 printf("open sysctl failed: %m\n");
115 abort();
116 }
117
118 if (write(fd, val, strlen(val)) >= 0) {
119 printf("write sysctl %s succeeded, but failure expected\n",
120 val);
121 abort();
122 }
123 }
124
sysctl_assert_equal(const char * val)125 static void sysctl_assert_equal(const char *val)
126 {
127 char *p, buf[128] = {};
128 int fd = open("/proc/sys/vm/memfd_noexec", O_RDONLY | O_CLOEXEC);
129
130 if (fd < 0) {
131 printf("open sysctl failed: %m\n");
132 abort();
133 }
134
135 if (read(fd, buf, sizeof(buf)) < 0) {
136 printf("read sysctl failed: %m\n");
137 abort();
138 }
139
140 /* Strip trailing whitespace. */
141 p = buf;
142 while (!isspace(*p))
143 p++;
144 *p = '\0';
145
146 if (strcmp(buf, val) != 0) {
147 printf("unexpected sysctl value: expected %s, got %s\n", val, buf);
148 abort();
149 }
150 }
151
mfd_assert_reopen_fd(int fd_in)152 static int mfd_assert_reopen_fd(int fd_in)
153 {
154 int fd;
155 char path[100];
156
157 sprintf(path, "/proc/self/fd/%d", fd_in);
158
159 fd = open(path, O_RDWR);
160 if (fd < 0) {
161 printf("re-open of existing fd %d failed\n", fd_in);
162 abort();
163 }
164
165 return fd;
166 }
167
mfd_fail_new(const char * name,unsigned int flags)168 static void mfd_fail_new(const char *name, unsigned int flags)
169 {
170 int r;
171
172 r = sys_memfd_create(name, flags);
173 if (r >= 0) {
174 printf("memfd_create(\"%s\", %u) succeeded, but failure expected\n",
175 name, flags);
176 close(r);
177 abort();
178 }
179 }
180
mfd_assert_get_seals(int fd)181 static unsigned int mfd_assert_get_seals(int fd)
182 {
183 int r;
184
185 r = fcntl(fd, F_GET_SEALS);
186 if (r < 0) {
187 printf("GET_SEALS(%d) failed: %m\n", fd);
188 abort();
189 }
190
191 return (unsigned int)r;
192 }
193
mfd_assert_has_seals(int fd,unsigned int seals)194 static void mfd_assert_has_seals(int fd, unsigned int seals)
195 {
196 char buf[PATH_MAX];
197 int nbytes;
198 unsigned int s;
199 fd2name(fd, buf, PATH_MAX);
200
201 s = mfd_assert_get_seals(fd);
202 if (s != seals) {
203 printf("%u != %u = GET_SEALS(%s)\n", seals, s, buf);
204 abort();
205 }
206 }
207
mfd_assert_add_seals(int fd,unsigned int seals)208 static void mfd_assert_add_seals(int fd, unsigned int seals)
209 {
210 int r;
211 unsigned int s;
212
213 s = mfd_assert_get_seals(fd);
214 r = fcntl(fd, F_ADD_SEALS, seals);
215 if (r < 0) {
216 printf("ADD_SEALS(%d, %u -> %u) failed: %m\n", fd, s, seals);
217 abort();
218 }
219 }
220
mfd_fail_add_seals(int fd,unsigned int seals)221 static void mfd_fail_add_seals(int fd, unsigned int seals)
222 {
223 int r;
224 unsigned int s;
225
226 r = fcntl(fd, F_GET_SEALS);
227 if (r < 0)
228 s = 0;
229 else
230 s = (unsigned int)r;
231
232 r = fcntl(fd, F_ADD_SEALS, seals);
233 if (r >= 0) {
234 printf("ADD_SEALS(%d, %u -> %u) didn't fail as expected\n",
235 fd, s, seals);
236 abort();
237 }
238 }
239
mfd_assert_size(int fd,size_t size)240 static void mfd_assert_size(int fd, size_t size)
241 {
242 struct stat st;
243 int r;
244
245 r = fstat(fd, &st);
246 if (r < 0) {
247 printf("fstat(%d) failed: %m\n", fd);
248 abort();
249 } else if (st.st_size != size) {
250 printf("wrong file size %lld, but expected %lld\n",
251 (long long)st.st_size, (long long)size);
252 abort();
253 }
254 }
255
mfd_assert_dup(int fd)256 static int mfd_assert_dup(int fd)
257 {
258 int r;
259
260 r = dup(fd);
261 if (r < 0) {
262 printf("dup(%d) failed: %m\n", fd);
263 abort();
264 }
265
266 return r;
267 }
268
mfd_assert_mmap_shared(int fd)269 static void *mfd_assert_mmap_shared(int fd)
270 {
271 void *p;
272
273 p = mmap(NULL,
274 mfd_def_size,
275 PROT_READ | PROT_WRITE,
276 MAP_SHARED,
277 fd,
278 0);
279 if (p == MAP_FAILED) {
280 printf("mmap() failed: %m\n");
281 abort();
282 }
283
284 return p;
285 }
286
mfd_assert_mmap_private(int fd)287 static void *mfd_assert_mmap_private(int fd)
288 {
289 void *p;
290
291 p = mmap(NULL,
292 mfd_def_size,
293 PROT_READ,
294 MAP_PRIVATE,
295 fd,
296 0);
297 if (p == MAP_FAILED) {
298 printf("mmap() failed: %m\n");
299 abort();
300 }
301
302 return p;
303 }
304
mfd_assert_open(int fd,int flags,mode_t mode)305 static int mfd_assert_open(int fd, int flags, mode_t mode)
306 {
307 char buf[512];
308 int r;
309
310 sprintf(buf, "/proc/self/fd/%d", fd);
311 r = open(buf, flags, mode);
312 if (r < 0) {
313 printf("open(%s) failed: %m\n", buf);
314 abort();
315 }
316
317 return r;
318 }
319
mfd_fail_open(int fd,int flags,mode_t mode)320 static void mfd_fail_open(int fd, int flags, mode_t mode)
321 {
322 char buf[512];
323 int r;
324
325 sprintf(buf, "/proc/self/fd/%d", fd);
326 r = open(buf, flags, mode);
327 if (r >= 0) {
328 printf("open(%s) didn't fail as expected\n", buf);
329 abort();
330 }
331 }
332
mfd_assert_read(int fd)333 static void mfd_assert_read(int fd)
334 {
335 char buf[16];
336 void *p;
337 ssize_t l;
338
339 l = read(fd, buf, sizeof(buf));
340 if (l != sizeof(buf)) {
341 printf("read() failed: %m\n");
342 abort();
343 }
344
345 /* verify PROT_READ *is* allowed */
346 p = mmap(NULL,
347 mfd_def_size,
348 PROT_READ,
349 MAP_PRIVATE,
350 fd,
351 0);
352 if (p == MAP_FAILED) {
353 printf("mmap() failed: %m\n");
354 abort();
355 }
356 munmap(p, mfd_def_size);
357
358 /* verify MAP_PRIVATE is *always* allowed (even writable) */
359 p = mmap(NULL,
360 mfd_def_size,
361 PROT_READ | PROT_WRITE,
362 MAP_PRIVATE,
363 fd,
364 0);
365 if (p == MAP_FAILED) {
366 printf("mmap() failed: %m\n");
367 abort();
368 }
369 munmap(p, mfd_def_size);
370 }
371
372 /* Test that PROT_READ + MAP_SHARED mappings work. */
mfd_assert_read_shared(int fd)373 static void mfd_assert_read_shared(int fd)
374 {
375 void *p;
376
377 /* verify PROT_READ and MAP_SHARED *is* allowed */
378 p = mmap(NULL,
379 mfd_def_size,
380 PROT_READ,
381 MAP_SHARED,
382 fd,
383 0);
384 if (p == MAP_FAILED) {
385 printf("mmap() failed: %m\n");
386 abort();
387 }
388 munmap(p, mfd_def_size);
389 }
390
mfd_assert_fork_private_write(int fd)391 static void mfd_assert_fork_private_write(int fd)
392 {
393 int *p;
394 pid_t pid;
395
396 p = mmap(NULL,
397 mfd_def_size,
398 PROT_READ | PROT_WRITE,
399 MAP_PRIVATE,
400 fd,
401 0);
402 if (p == MAP_FAILED) {
403 printf("mmap() failed: %m\n");
404 abort();
405 }
406
407 p[0] = 22;
408
409 pid = fork();
410 if (pid == 0) {
411 p[0] = 33;
412 exit(0);
413 } else {
414 waitpid(pid, NULL, 0);
415
416 if (p[0] != 22) {
417 printf("MAP_PRIVATE copy-on-write failed: %m\n");
418 abort();
419 }
420 }
421
422 munmap(p, mfd_def_size);
423 }
424
mfd_assert_write(int fd)425 static void mfd_assert_write(int fd)
426 {
427 ssize_t l;
428 void *p;
429 int r;
430
431 /*
432 * huegtlbfs does not support write, but we want to
433 * verify everything else here.
434 */
435 if (!hugetlbfs_test) {
436 /* verify write() succeeds */
437 l = write(fd, "\0\0\0\0", 4);
438 if (l != 4) {
439 printf("write() failed: %m\n");
440 abort();
441 }
442 }
443
444 /* verify PROT_READ | PROT_WRITE is allowed */
445 p = mmap(NULL,
446 mfd_def_size,
447 PROT_READ | PROT_WRITE,
448 MAP_SHARED,
449 fd,
450 0);
451 if (p == MAP_FAILED) {
452 printf("mmap() failed: %m\n");
453 abort();
454 }
455 *(char *)p = 0;
456 munmap(p, mfd_def_size);
457
458 /* verify PROT_WRITE is allowed */
459 p = mmap(NULL,
460 mfd_def_size,
461 PROT_WRITE,
462 MAP_SHARED,
463 fd,
464 0);
465 if (p == MAP_FAILED) {
466 printf("mmap() failed: %m\n");
467 abort();
468 }
469 *(char *)p = 0;
470 munmap(p, mfd_def_size);
471
472 /* verify PROT_READ with MAP_SHARED is allowed and a following
473 * mprotect(PROT_WRITE) allows writing */
474 p = mmap(NULL,
475 mfd_def_size,
476 PROT_READ,
477 MAP_SHARED,
478 fd,
479 0);
480 if (p == MAP_FAILED) {
481 printf("mmap() failed: %m\n");
482 abort();
483 }
484
485 r = mprotect(p, mfd_def_size, PROT_READ | PROT_WRITE);
486 if (r < 0) {
487 printf("mprotect() failed: %m\n");
488 abort();
489 }
490
491 *(char *)p = 0;
492 munmap(p, mfd_def_size);
493
494 /* verify PUNCH_HOLE works */
495 r = fallocate(fd,
496 FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
497 0,
498 mfd_def_size);
499 if (r < 0) {
500 printf("fallocate(PUNCH_HOLE) failed: %m\n");
501 abort();
502 }
503 }
504
mfd_fail_write(int fd)505 static void mfd_fail_write(int fd)
506 {
507 ssize_t l;
508 void *p;
509 int r;
510
511 /* verify write() fails */
512 l = write(fd, "data", 4);
513 if (l != -EPERM) {
514 printf("expected EPERM on write(), but got %d: %m\n", (int)l);
515 abort();
516 }
517
518 /* verify PROT_READ | PROT_WRITE is not allowed */
519 p = mmap(NULL,
520 mfd_def_size,
521 PROT_READ | PROT_WRITE,
522 MAP_SHARED,
523 fd,
524 0);
525 if (p != MAP_FAILED) {
526 printf("mmap() didn't fail as expected\n");
527 abort();
528 }
529
530 /* verify PROT_WRITE is not allowed */
531 p = mmap(NULL,
532 mfd_def_size,
533 PROT_WRITE,
534 MAP_SHARED,
535 fd,
536 0);
537 if (p != MAP_FAILED) {
538 printf("mmap() didn't fail as expected\n");
539 abort();
540 }
541
542 /* Verify PROT_READ with MAP_SHARED with a following mprotect is not
543 * allowed. Note that for r/w the kernel already prevents the mmap. */
544 p = mmap(NULL,
545 mfd_def_size,
546 PROT_READ,
547 MAP_SHARED,
548 fd,
549 0);
550 if (p != MAP_FAILED) {
551 r = mprotect(p, mfd_def_size, PROT_READ | PROT_WRITE);
552 if (r >= 0) {
553 printf("mmap()+mprotect() didn't fail as expected\n");
554 abort();
555 }
556 munmap(p, mfd_def_size);
557 }
558
559 /* verify PUNCH_HOLE fails */
560 r = fallocate(fd,
561 FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
562 0,
563 mfd_def_size);
564 if (r >= 0) {
565 printf("fallocate(PUNCH_HOLE) didn't fail as expected\n");
566 abort();
567 }
568 }
569
mfd_assert_shrink(int fd)570 static void mfd_assert_shrink(int fd)
571 {
572 int r, fd2;
573
574 r = ftruncate(fd, mfd_def_size / 2);
575 if (r < 0) {
576 printf("ftruncate(SHRINK) failed: %m\n");
577 abort();
578 }
579
580 mfd_assert_size(fd, mfd_def_size / 2);
581
582 fd2 = mfd_assert_open(fd,
583 O_RDWR | O_CREAT | O_TRUNC,
584 S_IRUSR | S_IWUSR);
585 close(fd2);
586
587 mfd_assert_size(fd, 0);
588 }
589
mfd_fail_shrink(int fd)590 static void mfd_fail_shrink(int fd)
591 {
592 int r;
593
594 r = ftruncate(fd, mfd_def_size / 2);
595 if (r >= 0) {
596 printf("ftruncate(SHRINK) didn't fail as expected\n");
597 abort();
598 }
599
600 mfd_fail_open(fd,
601 O_RDWR | O_CREAT | O_TRUNC,
602 S_IRUSR | S_IWUSR);
603 }
604
mfd_assert_grow(int fd)605 static void mfd_assert_grow(int fd)
606 {
607 int r;
608
609 r = ftruncate(fd, mfd_def_size * 2);
610 if (r < 0) {
611 printf("ftruncate(GROW) failed: %m\n");
612 abort();
613 }
614
615 mfd_assert_size(fd, mfd_def_size * 2);
616
617 r = fallocate(fd,
618 0,
619 0,
620 mfd_def_size * 4);
621 if (r < 0) {
622 printf("fallocate(ALLOC) failed: %m\n");
623 abort();
624 }
625
626 mfd_assert_size(fd, mfd_def_size * 4);
627 }
628
mfd_fail_grow(int fd)629 static void mfd_fail_grow(int fd)
630 {
631 int r;
632
633 r = ftruncate(fd, mfd_def_size * 2);
634 if (r >= 0) {
635 printf("ftruncate(GROW) didn't fail as expected\n");
636 abort();
637 }
638
639 r = fallocate(fd,
640 0,
641 0,
642 mfd_def_size * 4);
643 if (r >= 0) {
644 printf("fallocate(ALLOC) didn't fail as expected\n");
645 abort();
646 }
647 }
648
mfd_assert_grow_write(int fd)649 static void mfd_assert_grow_write(int fd)
650 {
651 static char *buf;
652 ssize_t l;
653
654 /* hugetlbfs does not support write */
655 if (hugetlbfs_test)
656 return;
657
658 buf = malloc(mfd_def_size * 8);
659 if (!buf) {
660 printf("malloc(%zu) failed: %m\n", mfd_def_size * 8);
661 abort();
662 }
663
664 l = pwrite(fd, buf, mfd_def_size * 8, 0);
665 if (l != (mfd_def_size * 8)) {
666 printf("pwrite() failed: %m\n");
667 abort();
668 }
669
670 mfd_assert_size(fd, mfd_def_size * 8);
671 }
672
mfd_fail_grow_write(int fd)673 static void mfd_fail_grow_write(int fd)
674 {
675 static char *buf;
676 ssize_t l;
677
678 /* hugetlbfs does not support write */
679 if (hugetlbfs_test)
680 return;
681
682 buf = malloc(mfd_def_size * 8);
683 if (!buf) {
684 printf("malloc(%zu) failed: %m\n", mfd_def_size * 8);
685 abort();
686 }
687
688 l = pwrite(fd, buf, mfd_def_size * 8, 0);
689 if (l == (mfd_def_size * 8)) {
690 printf("pwrite() didn't fail as expected\n");
691 abort();
692 }
693 }
694
mfd_assert_mode(int fd,int mode)695 static void mfd_assert_mode(int fd, int mode)
696 {
697 struct stat st;
698 char buf[PATH_MAX];
699 int nbytes;
700
701 fd2name(fd, buf, PATH_MAX);
702
703 if (fstat(fd, &st) < 0) {
704 printf("fstat(%s) failed: %m\n", buf);
705 abort();
706 }
707
708 if ((st.st_mode & 07777) != mode) {
709 printf("fstat(%s) wrong file mode 0%04o, but expected 0%04o\n",
710 buf, (int)st.st_mode & 07777, mode);
711 abort();
712 }
713 }
714
mfd_assert_chmod(int fd,int mode)715 static void mfd_assert_chmod(int fd, int mode)
716 {
717 char buf[PATH_MAX];
718 int nbytes;
719
720 fd2name(fd, buf, PATH_MAX);
721
722 if (fchmod(fd, mode) < 0) {
723 printf("fchmod(%s, 0%04o) failed: %m\n", buf, mode);
724 abort();
725 }
726
727 mfd_assert_mode(fd, mode);
728 }
729
mfd_fail_chmod(int fd,int mode)730 static void mfd_fail_chmod(int fd, int mode)
731 {
732 struct stat st;
733 char buf[PATH_MAX];
734 int nbytes;
735
736 fd2name(fd, buf, PATH_MAX);
737
738 if (fstat(fd, &st) < 0) {
739 printf("fstat(%s) failed: %m\n", buf);
740 abort();
741 }
742
743 if (fchmod(fd, mode) == 0) {
744 printf("fchmod(%s, 0%04o) didn't fail as expected\n",
745 buf, mode);
746 abort();
747 }
748
749 /* verify that file mode bits did not change */
750 mfd_assert_mode(fd, st.st_mode & 07777);
751 }
752
idle_thread_fn(void * arg)753 static int idle_thread_fn(void *arg)
754 {
755 sigset_t set;
756 int sig;
757
758 /* dummy waiter; SIGTERM terminates us anyway */
759 sigemptyset(&set);
760 sigaddset(&set, SIGTERM);
761 sigwait(&set, &sig);
762
763 return 0;
764 }
765
spawn_thread(unsigned int flags,int (* fn)(void *),void * arg)766 static pid_t spawn_thread(unsigned int flags, int (*fn)(void *), void *arg)
767 {
768 uint8_t *stack;
769 pid_t pid;
770
771 stack = malloc(STACK_SIZE);
772 if (!stack) {
773 printf("malloc(STACK_SIZE) failed: %m\n");
774 abort();
775 }
776
777 pid = clone(fn, stack + STACK_SIZE, SIGCHLD | flags, arg);
778 if (pid < 0) {
779 printf("clone() failed: %m\n");
780 abort();
781 }
782
783 return pid;
784 }
785
join_thread(pid_t pid)786 static void join_thread(pid_t pid)
787 {
788 int wstatus;
789
790 if (waitpid(pid, &wstatus, 0) < 0) {
791 printf("newpid thread: waitpid() failed: %m\n");
792 abort();
793 }
794
795 if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) != 0) {
796 printf("newpid thread: exited with non-zero error code %d\n",
797 WEXITSTATUS(wstatus));
798 abort();
799 }
800
801 if (WIFSIGNALED(wstatus)) {
802 printf("newpid thread: killed by signal %d\n",
803 WTERMSIG(wstatus));
804 abort();
805 }
806 }
807
spawn_idle_thread(unsigned int flags)808 static pid_t spawn_idle_thread(unsigned int flags)
809 {
810 return spawn_thread(flags, idle_thread_fn, NULL);
811 }
812
join_idle_thread(pid_t pid)813 static void join_idle_thread(pid_t pid)
814 {
815 kill(pid, SIGTERM);
816 waitpid(pid, NULL, 0);
817 }
818
819 /*
820 * Test memfd_create() syscall
821 * Verify syscall-argument validation, including name checks, flag validation
822 * and more.
823 */
test_create(void)824 static void test_create(void)
825 {
826 char buf[2048];
827 int fd;
828
829 printf("%s CREATE\n", memfd_str);
830
831 /* test NULL name */
832 mfd_fail_new(NULL, 0);
833
834 /* test over-long name (not zero-terminated) */
835 memset(buf, 0xff, sizeof(buf));
836 mfd_fail_new(buf, 0);
837
838 /* test over-long zero-terminated name */
839 memset(buf, 0xff, sizeof(buf));
840 buf[sizeof(buf) - 1] = 0;
841 mfd_fail_new(buf, 0);
842
843 /* verify "" is a valid name */
844 fd = mfd_assert_new("", 0, 0);
845 close(fd);
846
847 /* verify invalid O_* open flags */
848 mfd_fail_new("", 0x0100);
849 mfd_fail_new("", ~MFD_CLOEXEC);
850 mfd_fail_new("", ~MFD_ALLOW_SEALING);
851 mfd_fail_new("", ~0);
852 mfd_fail_new("", 0x80000000U);
853
854 /* verify EXEC and NOEXEC_SEAL can't both be set */
855 mfd_fail_new("", MFD_EXEC | MFD_NOEXEC_SEAL);
856
857 /* verify MFD_CLOEXEC is allowed */
858 fd = mfd_assert_new("", 0, MFD_CLOEXEC);
859 close(fd);
860
861 /* verify MFD_ALLOW_SEALING is allowed */
862 fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING);
863 close(fd);
864
865 /* verify MFD_ALLOW_SEALING | MFD_CLOEXEC is allowed */
866 fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING | MFD_CLOEXEC);
867 close(fd);
868 }
869
870 /*
871 * Test basic sealing
872 * A very basic sealing test to see whether setting/retrieving seals works.
873 */
test_basic(void)874 static void test_basic(void)
875 {
876 int fd;
877
878 printf("%s BASIC\n", memfd_str);
879
880 fd = mfd_assert_new("kern_memfd_basic",
881 mfd_def_size,
882 MFD_CLOEXEC | MFD_ALLOW_SEALING);
883
884 /* add basic seals */
885 mfd_assert_has_seals(fd, 0);
886 mfd_assert_add_seals(fd, F_SEAL_SHRINK |
887 F_SEAL_WRITE);
888 mfd_assert_has_seals(fd, F_SEAL_SHRINK |
889 F_SEAL_WRITE);
890
891 /* add them again */
892 mfd_assert_add_seals(fd, F_SEAL_SHRINK |
893 F_SEAL_WRITE);
894 mfd_assert_has_seals(fd, F_SEAL_SHRINK |
895 F_SEAL_WRITE);
896
897 /* add more seals and seal against sealing */
898 mfd_assert_add_seals(fd, F_SEAL_GROW | F_SEAL_SEAL);
899 mfd_assert_has_seals(fd, F_SEAL_SHRINK |
900 F_SEAL_GROW |
901 F_SEAL_WRITE |
902 F_SEAL_SEAL);
903
904 /* verify that sealing no longer works */
905 mfd_fail_add_seals(fd, F_SEAL_GROW);
906 mfd_fail_add_seals(fd, 0);
907
908 close(fd);
909
910 /* verify sealing does not work without MFD_ALLOW_SEALING */
911 fd = mfd_assert_new("kern_memfd_basic",
912 mfd_def_size,
913 MFD_CLOEXEC);
914 mfd_assert_has_seals(fd, F_SEAL_SEAL);
915 mfd_fail_add_seals(fd, F_SEAL_SHRINK |
916 F_SEAL_GROW |
917 F_SEAL_WRITE);
918 mfd_assert_has_seals(fd, F_SEAL_SEAL);
919 close(fd);
920 }
921
922 /*
923 * Test SEAL_WRITE
924 * Test whether SEAL_WRITE actually prevents modifications.
925 */
test_seal_write(void)926 static void test_seal_write(void)
927 {
928 int fd;
929
930 printf("%s SEAL-WRITE\n", memfd_str);
931
932 fd = mfd_assert_new("kern_memfd_seal_write",
933 mfd_def_size,
934 MFD_CLOEXEC | MFD_ALLOW_SEALING);
935 mfd_assert_has_seals(fd, 0);
936 mfd_assert_add_seals(fd, F_SEAL_WRITE);
937 mfd_assert_has_seals(fd, F_SEAL_WRITE);
938
939 mfd_assert_read(fd);
940 mfd_fail_write(fd);
941 mfd_assert_shrink(fd);
942 mfd_assert_grow(fd);
943 mfd_fail_grow_write(fd);
944
945 close(fd);
946 }
947
948 /*
949 * Test SEAL_FUTURE_WRITE
950 * Test whether SEAL_FUTURE_WRITE actually prevents modifications.
951 */
test_seal_future_write(void)952 static void test_seal_future_write(void)
953 {
954 int fd, fd2;
955 void *p;
956
957 printf("%s SEAL-FUTURE-WRITE\n", memfd_str);
958
959 fd = mfd_assert_new("kern_memfd_seal_future_write",
960 mfd_def_size,
961 MFD_CLOEXEC | MFD_ALLOW_SEALING);
962
963 p = mfd_assert_mmap_shared(fd);
964
965 mfd_assert_has_seals(fd, 0);
966
967 mfd_assert_add_seals(fd, F_SEAL_FUTURE_WRITE);
968 mfd_assert_has_seals(fd, F_SEAL_FUTURE_WRITE);
969
970 /* read should pass, writes should fail */
971 mfd_assert_read(fd);
972 mfd_assert_read_shared(fd);
973 mfd_fail_write(fd);
974
975 fd2 = mfd_assert_reopen_fd(fd);
976 /* read should pass, writes should still fail */
977 mfd_assert_read(fd2);
978 mfd_assert_read_shared(fd2);
979 mfd_fail_write(fd2);
980
981 mfd_assert_fork_private_write(fd);
982
983 munmap(p, mfd_def_size);
984 close(fd2);
985 close(fd);
986 }
987
988 /*
989 * Test SEAL_SHRINK
990 * Test whether SEAL_SHRINK actually prevents shrinking
991 */
test_seal_shrink(void)992 static void test_seal_shrink(void)
993 {
994 int fd;
995
996 printf("%s SEAL-SHRINK\n", memfd_str);
997
998 fd = mfd_assert_new("kern_memfd_seal_shrink",
999 mfd_def_size,
1000 MFD_CLOEXEC | MFD_ALLOW_SEALING);
1001 mfd_assert_has_seals(fd, 0);
1002 mfd_assert_add_seals(fd, F_SEAL_SHRINK);
1003 mfd_assert_has_seals(fd, F_SEAL_SHRINK);
1004
1005 mfd_assert_read(fd);
1006 mfd_assert_write(fd);
1007 mfd_fail_shrink(fd);
1008 mfd_assert_grow(fd);
1009 mfd_assert_grow_write(fd);
1010
1011 close(fd);
1012 }
1013
1014 /*
1015 * Test SEAL_GROW
1016 * Test whether SEAL_GROW actually prevents growing
1017 */
test_seal_grow(void)1018 static void test_seal_grow(void)
1019 {
1020 int fd;
1021
1022 printf("%s SEAL-GROW\n", memfd_str);
1023
1024 fd = mfd_assert_new("kern_memfd_seal_grow",
1025 mfd_def_size,
1026 MFD_CLOEXEC | MFD_ALLOW_SEALING);
1027 mfd_assert_has_seals(fd, 0);
1028 mfd_assert_add_seals(fd, F_SEAL_GROW);
1029 mfd_assert_has_seals(fd, F_SEAL_GROW);
1030
1031 mfd_assert_read(fd);
1032 mfd_assert_write(fd);
1033 mfd_assert_shrink(fd);
1034 mfd_fail_grow(fd);
1035 mfd_fail_grow_write(fd);
1036
1037 close(fd);
1038 }
1039
1040 /*
1041 * Test SEAL_SHRINK | SEAL_GROW
1042 * Test whether SEAL_SHRINK | SEAL_GROW actually prevents resizing
1043 */
test_seal_resize(void)1044 static void test_seal_resize(void)
1045 {
1046 int fd;
1047
1048 printf("%s SEAL-RESIZE\n", memfd_str);
1049
1050 fd = mfd_assert_new("kern_memfd_seal_resize",
1051 mfd_def_size,
1052 MFD_CLOEXEC | MFD_ALLOW_SEALING);
1053 mfd_assert_has_seals(fd, 0);
1054 mfd_assert_add_seals(fd, F_SEAL_SHRINK | F_SEAL_GROW);
1055 mfd_assert_has_seals(fd, F_SEAL_SHRINK | F_SEAL_GROW);
1056
1057 mfd_assert_read(fd);
1058 mfd_assert_write(fd);
1059 mfd_fail_shrink(fd);
1060 mfd_fail_grow(fd);
1061 mfd_fail_grow_write(fd);
1062
1063 close(fd);
1064 }
1065
1066 /*
1067 * Test SEAL_EXEC
1068 * Test fd is created with exec and allow sealing.
1069 * chmod() cannot change x bits after sealing.
1070 */
test_exec_seal(void)1071 static void test_exec_seal(void)
1072 {
1073 int fd;
1074
1075 printf("%s SEAL-EXEC\n", memfd_str);
1076
1077 printf("%s Apply SEAL_EXEC\n", memfd_str);
1078 fd = mfd_assert_new("kern_memfd_seal_exec",
1079 mfd_def_size,
1080 MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_EXEC);
1081
1082 mfd_assert_mode(fd, 0777);
1083 mfd_assert_chmod(fd, 0644);
1084
1085 mfd_assert_has_seals(fd, 0);
1086 mfd_assert_add_seals(fd, F_SEAL_EXEC);
1087 mfd_assert_has_seals(fd, F_SEAL_EXEC);
1088
1089 mfd_assert_chmod(fd, 0600);
1090 mfd_fail_chmod(fd, 0777);
1091 mfd_fail_chmod(fd, 0670);
1092 mfd_fail_chmod(fd, 0605);
1093 mfd_fail_chmod(fd, 0700);
1094 mfd_fail_chmod(fd, 0100);
1095 mfd_assert_chmod(fd, 0666);
1096 mfd_assert_write(fd);
1097 close(fd);
1098
1099 printf("%s Apply ALL_SEALS\n", memfd_str);
1100 fd = mfd_assert_new("kern_memfd_seal_exec",
1101 mfd_def_size,
1102 MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_EXEC);
1103
1104 mfd_assert_mode(fd, 0777);
1105 mfd_assert_chmod(fd, 0700);
1106
1107 mfd_assert_has_seals(fd, 0);
1108 mfd_assert_add_seals(fd, F_SEAL_EXEC);
1109 mfd_assert_has_seals(fd, F_WX_SEALS);
1110
1111 mfd_fail_chmod(fd, 0711);
1112 mfd_fail_chmod(fd, 0600);
1113 mfd_fail_write(fd);
1114 close(fd);
1115 }
1116
1117 /*
1118 * Test EXEC_NO_SEAL
1119 * Test fd is created with exec and not allow sealing.
1120 */
test_exec_no_seal(void)1121 static void test_exec_no_seal(void)
1122 {
1123 int fd;
1124
1125 printf("%s EXEC_NO_SEAL\n", memfd_str);
1126
1127 /* Create with EXEC but without ALLOW_SEALING */
1128 fd = mfd_assert_new("kern_memfd_exec_no_sealing",
1129 mfd_def_size,
1130 MFD_CLOEXEC | MFD_EXEC);
1131 mfd_assert_mode(fd, 0777);
1132 mfd_assert_has_seals(fd, F_SEAL_SEAL);
1133 mfd_assert_chmod(fd, 0666);
1134 close(fd);
1135 }
1136
1137 /*
1138 * Test memfd_create with MFD_NOEXEC flag
1139 */
test_noexec_seal(void)1140 static void test_noexec_seal(void)
1141 {
1142 int fd;
1143
1144 printf("%s NOEXEC_SEAL\n", memfd_str);
1145
1146 /* Create with NOEXEC and ALLOW_SEALING */
1147 fd = mfd_assert_new("kern_memfd_noexec",
1148 mfd_def_size,
1149 MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_NOEXEC_SEAL);
1150 mfd_assert_mode(fd, 0666);
1151 mfd_assert_has_seals(fd, F_SEAL_EXEC);
1152 mfd_fail_chmod(fd, 0777);
1153 close(fd);
1154
1155 /* Create with NOEXEC but without ALLOW_SEALING */
1156 fd = mfd_assert_new("kern_memfd_noexec",
1157 mfd_def_size,
1158 MFD_CLOEXEC | MFD_NOEXEC_SEAL);
1159 mfd_assert_mode(fd, 0666);
1160 mfd_assert_has_seals(fd, F_SEAL_EXEC);
1161 mfd_fail_chmod(fd, 0777);
1162 close(fd);
1163 }
1164
test_sysctl_sysctl0(void)1165 static void test_sysctl_sysctl0(void)
1166 {
1167 int fd;
1168
1169 sysctl_assert_equal("0");
1170
1171 fd = mfd_assert_new("kern_memfd_sysctl_0_dfl",
1172 mfd_def_size,
1173 MFD_CLOEXEC | MFD_ALLOW_SEALING);
1174 mfd_assert_mode(fd, 0777);
1175 mfd_assert_has_seals(fd, 0);
1176 mfd_assert_chmod(fd, 0644);
1177 close(fd);
1178 }
1179
test_sysctl_set_sysctl0(void)1180 static void test_sysctl_set_sysctl0(void)
1181 {
1182 sysctl_assert_write("0");
1183 test_sysctl_sysctl0();
1184 }
1185
test_sysctl_sysctl1(void)1186 static void test_sysctl_sysctl1(void)
1187 {
1188 int fd;
1189
1190 sysctl_assert_equal("1");
1191
1192 fd = mfd_assert_new("kern_memfd_sysctl_1_dfl",
1193 mfd_def_size,
1194 MFD_CLOEXEC | MFD_ALLOW_SEALING);
1195 mfd_assert_mode(fd, 0666);
1196 mfd_assert_has_seals(fd, F_SEAL_EXEC);
1197 mfd_fail_chmod(fd, 0777);
1198 close(fd);
1199
1200 fd = mfd_assert_new("kern_memfd_sysctl_1_exec",
1201 mfd_def_size,
1202 MFD_CLOEXEC | MFD_EXEC | MFD_ALLOW_SEALING);
1203 mfd_assert_mode(fd, 0777);
1204 mfd_assert_has_seals(fd, 0);
1205 mfd_assert_chmod(fd, 0644);
1206 close(fd);
1207
1208 fd = mfd_assert_new("kern_memfd_sysctl_1_noexec",
1209 mfd_def_size,
1210 MFD_CLOEXEC | MFD_NOEXEC_SEAL | MFD_ALLOW_SEALING);
1211 mfd_assert_mode(fd, 0666);
1212 mfd_assert_has_seals(fd, F_SEAL_EXEC);
1213 mfd_fail_chmod(fd, 0777);
1214 close(fd);
1215 }
1216
test_sysctl_set_sysctl1(void)1217 static void test_sysctl_set_sysctl1(void)
1218 {
1219 sysctl_assert_write("1");
1220 test_sysctl_sysctl1();
1221 }
1222
test_sysctl_sysctl2(void)1223 static void test_sysctl_sysctl2(void)
1224 {
1225 int fd;
1226
1227 sysctl_assert_equal("2");
1228
1229 fd = mfd_assert_new("kern_memfd_sysctl_2_dfl",
1230 mfd_def_size,
1231 MFD_CLOEXEC | MFD_ALLOW_SEALING);
1232 mfd_assert_mode(fd, 0666);
1233 mfd_assert_has_seals(fd, F_SEAL_EXEC);
1234 mfd_fail_chmod(fd, 0777);
1235 close(fd);
1236
1237 mfd_fail_new("kern_memfd_sysctl_2_exec",
1238 MFD_CLOEXEC | MFD_EXEC | MFD_ALLOW_SEALING);
1239
1240 fd = mfd_assert_new("kern_memfd_sysctl_2_noexec",
1241 mfd_def_size,
1242 MFD_CLOEXEC | MFD_NOEXEC_SEAL | MFD_ALLOW_SEALING);
1243 mfd_assert_mode(fd, 0666);
1244 mfd_assert_has_seals(fd, F_SEAL_EXEC);
1245 mfd_fail_chmod(fd, 0777);
1246 close(fd);
1247 }
1248
test_sysctl_set_sysctl2(void)1249 static void test_sysctl_set_sysctl2(void)
1250 {
1251 sysctl_assert_write("2");
1252 test_sysctl_sysctl2();
1253 }
1254
sysctl_simple_child(void * arg)1255 static int sysctl_simple_child(void *arg)
1256 {
1257 int fd;
1258 int pid;
1259
1260 printf("%s sysctl 0\n", memfd_str);
1261 test_sysctl_set_sysctl0();
1262
1263 printf("%s sysctl 1\n", memfd_str);
1264 test_sysctl_set_sysctl1();
1265
1266 printf("%s sysctl 0\n", memfd_str);
1267 test_sysctl_set_sysctl0();
1268
1269 printf("%s sysctl 2\n", memfd_str);
1270 test_sysctl_set_sysctl2();
1271
1272 printf("%s sysctl 1\n", memfd_str);
1273 test_sysctl_set_sysctl1();
1274
1275 printf("%s sysctl 0\n", memfd_str);
1276 test_sysctl_set_sysctl0();
1277
1278 return 0;
1279 }
1280
1281 /*
1282 * Test sysctl
1283 * A very basic test to make sure the core sysctl semantics work.
1284 */
test_sysctl_simple(void)1285 static void test_sysctl_simple(void)
1286 {
1287 int pid = spawn_thread(CLONE_NEWPID, sysctl_simple_child, NULL);
1288
1289 join_thread(pid);
1290 }
1291
sysctl_nested(void * arg)1292 static int sysctl_nested(void *arg)
1293 {
1294 void (*fn)(void) = arg;
1295
1296 fn();
1297 return 0;
1298 }
1299
sysctl_nested_wait(void * arg)1300 static int sysctl_nested_wait(void *arg)
1301 {
1302 /* Wait for a SIGCONT. */
1303 kill(getpid(), SIGSTOP);
1304 return sysctl_nested(arg);
1305 }
1306
test_sysctl_sysctl1_failset(void)1307 static void test_sysctl_sysctl1_failset(void)
1308 {
1309 sysctl_fail_write("0");
1310 test_sysctl_sysctl1();
1311 }
1312
test_sysctl_sysctl2_failset(void)1313 static void test_sysctl_sysctl2_failset(void)
1314 {
1315 sysctl_fail_write("1");
1316 test_sysctl_sysctl2();
1317
1318 sysctl_fail_write("0");
1319 test_sysctl_sysctl2();
1320 }
1321
sysctl_nested_child(void * arg)1322 static int sysctl_nested_child(void *arg)
1323 {
1324 int fd;
1325 int pid;
1326
1327 printf("%s nested sysctl 0\n", memfd_str);
1328 sysctl_assert_write("0");
1329 /* A further nested pidns works the same. */
1330 pid = spawn_thread(CLONE_NEWPID, sysctl_simple_child, NULL);
1331 join_thread(pid);
1332
1333 printf("%s nested sysctl 1\n", memfd_str);
1334 sysctl_assert_write("1");
1335 /* Child inherits our setting. */
1336 pid = spawn_thread(CLONE_NEWPID, sysctl_nested, test_sysctl_sysctl1);
1337 join_thread(pid);
1338 /* Child cannot raise the setting. */
1339 pid = spawn_thread(CLONE_NEWPID, sysctl_nested,
1340 test_sysctl_sysctl1_failset);
1341 join_thread(pid);
1342 /* Child can lower the setting. */
1343 pid = spawn_thread(CLONE_NEWPID, sysctl_nested,
1344 test_sysctl_set_sysctl2);
1345 join_thread(pid);
1346 /* Child lowering the setting has no effect on our setting. */
1347 test_sysctl_sysctl1();
1348
1349 printf("%s nested sysctl 2\n", memfd_str);
1350 sysctl_assert_write("2");
1351 /* Child inherits our setting. */
1352 pid = spawn_thread(CLONE_NEWPID, sysctl_nested, test_sysctl_sysctl2);
1353 join_thread(pid);
1354 /* Child cannot raise the setting. */
1355 pid = spawn_thread(CLONE_NEWPID, sysctl_nested,
1356 test_sysctl_sysctl2_failset);
1357 join_thread(pid);
1358
1359 /* Verify that the rules are actually inherited after fork. */
1360 printf("%s nested sysctl 0 -> 1 after fork\n", memfd_str);
1361 sysctl_assert_write("0");
1362
1363 pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
1364 test_sysctl_sysctl1_failset);
1365 sysctl_assert_write("1");
1366 kill(pid, SIGCONT);
1367 join_thread(pid);
1368
1369 printf("%s nested sysctl 0 -> 2 after fork\n", memfd_str);
1370 sysctl_assert_write("0");
1371
1372 pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
1373 test_sysctl_sysctl2_failset);
1374 sysctl_assert_write("2");
1375 kill(pid, SIGCONT);
1376 join_thread(pid);
1377
1378 /*
1379 * Verify that the current effective setting is saved on fork, meaning
1380 * that the parent lowering the sysctl doesn't affect already-forked
1381 * children.
1382 */
1383 printf("%s nested sysctl 2 -> 1 after fork\n", memfd_str);
1384 sysctl_assert_write("2");
1385 pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
1386 test_sysctl_sysctl2);
1387 sysctl_assert_write("1");
1388 kill(pid, SIGCONT);
1389 join_thread(pid);
1390
1391 printf("%s nested sysctl 2 -> 0 after fork\n", memfd_str);
1392 sysctl_assert_write("2");
1393 pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
1394 test_sysctl_sysctl2);
1395 sysctl_assert_write("0");
1396 kill(pid, SIGCONT);
1397 join_thread(pid);
1398
1399 printf("%s nested sysctl 1 -> 0 after fork\n", memfd_str);
1400 sysctl_assert_write("1");
1401 pid = spawn_thread(CLONE_NEWPID, sysctl_nested_wait,
1402 test_sysctl_sysctl1);
1403 sysctl_assert_write("0");
1404 kill(pid, SIGCONT);
1405 join_thread(pid);
1406
1407 return 0;
1408 }
1409
1410 /*
1411 * Test sysctl with nested pid namespaces
1412 * Make sure that the sysctl nesting semantics work correctly.
1413 */
test_sysctl_nested(void)1414 static void test_sysctl_nested(void)
1415 {
1416 int pid = spawn_thread(CLONE_NEWPID, sysctl_nested_child, NULL);
1417
1418 join_thread(pid);
1419 }
1420
1421 /*
1422 * Test sharing via dup()
1423 * Test that seals are shared between dupped FDs and they're all equal.
1424 */
test_share_dup(char * banner,char * b_suffix)1425 static void test_share_dup(char *banner, char *b_suffix)
1426 {
1427 int fd, fd2;
1428
1429 printf("%s %s %s\n", memfd_str, banner, b_suffix);
1430
1431 fd = mfd_assert_new("kern_memfd_share_dup",
1432 mfd_def_size,
1433 MFD_CLOEXEC | MFD_ALLOW_SEALING);
1434 mfd_assert_has_seals(fd, 0);
1435
1436 fd2 = mfd_assert_dup(fd);
1437 mfd_assert_has_seals(fd2, 0);
1438
1439 mfd_assert_add_seals(fd, F_SEAL_WRITE);
1440 mfd_assert_has_seals(fd, F_SEAL_WRITE);
1441 mfd_assert_has_seals(fd2, F_SEAL_WRITE);
1442
1443 mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
1444 mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
1445 mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
1446
1447 mfd_assert_add_seals(fd, F_SEAL_SEAL);
1448 mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
1449 mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
1450
1451 mfd_fail_add_seals(fd, F_SEAL_GROW);
1452 mfd_fail_add_seals(fd2, F_SEAL_GROW);
1453 mfd_fail_add_seals(fd, F_SEAL_SEAL);
1454 mfd_fail_add_seals(fd2, F_SEAL_SEAL);
1455
1456 close(fd2);
1457
1458 mfd_fail_add_seals(fd, F_SEAL_GROW);
1459 close(fd);
1460 }
1461
1462 /*
1463 * Test sealing with active mmap()s
1464 * Modifying seals is only allowed if no other mmap() refs exist.
1465 */
test_share_mmap(char * banner,char * b_suffix)1466 static void test_share_mmap(char *banner, char *b_suffix)
1467 {
1468 int fd;
1469 void *p;
1470
1471 printf("%s %s %s\n", memfd_str, banner, b_suffix);
1472
1473 fd = mfd_assert_new("kern_memfd_share_mmap",
1474 mfd_def_size,
1475 MFD_CLOEXEC | MFD_ALLOW_SEALING);
1476 mfd_assert_has_seals(fd, 0);
1477
1478 /* shared/writable ref prevents sealing WRITE, but allows others */
1479 p = mfd_assert_mmap_shared(fd);
1480 mfd_fail_add_seals(fd, F_SEAL_WRITE);
1481 mfd_assert_has_seals(fd, 0);
1482 mfd_assert_add_seals(fd, F_SEAL_SHRINK);
1483 mfd_assert_has_seals(fd, F_SEAL_SHRINK);
1484 munmap(p, mfd_def_size);
1485
1486 /* readable ref allows sealing */
1487 p = mfd_assert_mmap_private(fd);
1488 mfd_assert_add_seals(fd, F_SEAL_WRITE);
1489 mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
1490 munmap(p, mfd_def_size);
1491
1492 close(fd);
1493 }
1494
1495 /*
1496 * Test sealing with open(/proc/self/fd/%d)
1497 * Via /proc we can get access to a separate file-context for the same memfd.
1498 * This is *not* like dup(), but like a real separate open(). Make sure the
1499 * semantics are as expected and we correctly check for RDONLY / WRONLY / RDWR.
1500 */
test_share_open(char * banner,char * b_suffix)1501 static void test_share_open(char *banner, char *b_suffix)
1502 {
1503 int fd, fd2;
1504
1505 printf("%s %s %s\n", memfd_str, banner, b_suffix);
1506
1507 fd = mfd_assert_new("kern_memfd_share_open",
1508 mfd_def_size,
1509 MFD_CLOEXEC | MFD_ALLOW_SEALING);
1510 mfd_assert_has_seals(fd, 0);
1511
1512 fd2 = mfd_assert_open(fd, O_RDWR, 0);
1513 mfd_assert_add_seals(fd, F_SEAL_WRITE);
1514 mfd_assert_has_seals(fd, F_SEAL_WRITE);
1515 mfd_assert_has_seals(fd2, F_SEAL_WRITE);
1516
1517 mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
1518 mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
1519 mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
1520
1521 close(fd);
1522 fd = mfd_assert_open(fd2, O_RDONLY, 0);
1523
1524 mfd_fail_add_seals(fd, F_SEAL_SEAL);
1525 mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
1526 mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
1527
1528 close(fd2);
1529 fd2 = mfd_assert_open(fd, O_RDWR, 0);
1530
1531 mfd_assert_add_seals(fd2, F_SEAL_SEAL);
1532 mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
1533 mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
1534
1535 close(fd2);
1536 close(fd);
1537 }
1538
1539 /*
1540 * Test sharing via fork()
1541 * Test whether seal-modifications work as expected with forked childs.
1542 */
test_share_fork(char * banner,char * b_suffix)1543 static void test_share_fork(char *banner, char *b_suffix)
1544 {
1545 int fd;
1546 pid_t pid;
1547
1548 printf("%s %s %s\n", memfd_str, banner, b_suffix);
1549
1550 fd = mfd_assert_new("kern_memfd_share_fork",
1551 mfd_def_size,
1552 MFD_CLOEXEC | MFD_ALLOW_SEALING);
1553 mfd_assert_has_seals(fd, 0);
1554
1555 pid = spawn_idle_thread(0);
1556 mfd_assert_add_seals(fd, F_SEAL_SEAL);
1557 mfd_assert_has_seals(fd, F_SEAL_SEAL);
1558
1559 mfd_fail_add_seals(fd, F_SEAL_WRITE);
1560 mfd_assert_has_seals(fd, F_SEAL_SEAL);
1561
1562 join_idle_thread(pid);
1563
1564 mfd_fail_add_seals(fd, F_SEAL_WRITE);
1565 mfd_assert_has_seals(fd, F_SEAL_SEAL);
1566
1567 close(fd);
1568 }
1569
main(int argc,char ** argv)1570 int main(int argc, char **argv)
1571 {
1572 pid_t pid;
1573
1574 if (argc == 2) {
1575 if (!strcmp(argv[1], "hugetlbfs")) {
1576 unsigned long hpage_size = default_huge_page_size();
1577
1578 if (!hpage_size) {
1579 printf("Unable to determine huge page size\n");
1580 abort();
1581 }
1582
1583 hugetlbfs_test = 1;
1584 memfd_str = MEMFD_HUGE_STR;
1585 mfd_def_size = hpage_size * 2;
1586 } else {
1587 printf("Unknown option: %s\n", argv[1]);
1588 abort();
1589 }
1590 }
1591
1592 test_create();
1593 test_basic();
1594 test_exec_seal();
1595 test_exec_no_seal();
1596 test_noexec_seal();
1597
1598 test_seal_write();
1599 test_seal_future_write();
1600 test_seal_shrink();
1601 test_seal_grow();
1602 test_seal_resize();
1603
1604 test_sysctl_simple();
1605 test_sysctl_nested();
1606
1607 test_share_dup("SHARE-DUP", "");
1608 test_share_mmap("SHARE-MMAP", "");
1609 test_share_open("SHARE-OPEN", "");
1610 test_share_fork("SHARE-FORK", "");
1611
1612 /* Run test-suite in a multi-threaded environment with a shared
1613 * file-table. */
1614 pid = spawn_idle_thread(CLONE_FILES | CLONE_FS | CLONE_VM);
1615 test_share_dup("SHARE-DUP", SHARED_FT_STR);
1616 test_share_mmap("SHARE-MMAP", SHARED_FT_STR);
1617 test_share_open("SHARE-OPEN", SHARED_FT_STR);
1618 test_share_fork("SHARE-FORK", SHARED_FT_STR);
1619 join_idle_thread(pid);
1620
1621 printf("memfd: DONE\n");
1622
1623 return 0;
1624 }
1625