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 <linux/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
22 #include "common.h"
23
24 #define MEMFD_STR "memfd:"
25 #define MEMFD_HUGE_STR "memfd-hugetlb:"
26 #define SHARED_FT_STR "(shared file-table)"
27
28 #define MFD_DEF_SIZE 8192
29 #define STACK_SIZE 65536
30
31 /*
32 * Default is not to test hugetlbfs
33 */
34 static size_t mfd_def_size = MFD_DEF_SIZE;
35 static const char *memfd_str = MEMFD_STR;
36
mfd_assert_new(const char * name,loff_t sz,unsigned int flags)37 static int mfd_assert_new(const char *name, loff_t sz, unsigned int flags)
38 {
39 int r, fd;
40
41 fd = sys_memfd_create(name, flags);
42 if (fd < 0) {
43 printf("memfd_create(\"%s\", %u) failed: %m\n",
44 name, flags);
45 abort();
46 }
47
48 r = ftruncate(fd, sz);
49 if (r < 0) {
50 printf("ftruncate(%llu) failed: %m\n", (unsigned long long)sz);
51 abort();
52 }
53
54 return fd;
55 }
56
mfd_fail_new(const char * name,unsigned int flags)57 static void mfd_fail_new(const char *name, unsigned int flags)
58 {
59 int r;
60
61 r = sys_memfd_create(name, flags);
62 if (r >= 0) {
63 printf("memfd_create(\"%s\", %u) succeeded, but failure expected\n",
64 name, flags);
65 close(r);
66 abort();
67 }
68 }
69
mfd_assert_get_seals(int fd)70 static unsigned int mfd_assert_get_seals(int fd)
71 {
72 int r;
73
74 r = fcntl(fd, F_GET_SEALS);
75 if (r < 0) {
76 printf("GET_SEALS(%d) failed: %m\n", fd);
77 abort();
78 }
79
80 return (unsigned int)r;
81 }
82
mfd_assert_has_seals(int fd,unsigned int seals)83 static void mfd_assert_has_seals(int fd, unsigned int seals)
84 {
85 unsigned int s;
86
87 s = mfd_assert_get_seals(fd);
88 if (s != seals) {
89 printf("%u != %u = GET_SEALS(%d)\n", seals, s, fd);
90 abort();
91 }
92 }
93
mfd_assert_add_seals(int fd,unsigned int seals)94 static void mfd_assert_add_seals(int fd, unsigned int seals)
95 {
96 int r;
97 unsigned int s;
98
99 s = mfd_assert_get_seals(fd);
100 r = fcntl(fd, F_ADD_SEALS, seals);
101 if (r < 0) {
102 printf("ADD_SEALS(%d, %u -> %u) failed: %m\n", fd, s, seals);
103 abort();
104 }
105 }
106
mfd_fail_add_seals(int fd,unsigned int seals)107 static void mfd_fail_add_seals(int fd, unsigned int seals)
108 {
109 int r;
110 unsigned int s;
111
112 r = fcntl(fd, F_GET_SEALS);
113 if (r < 0)
114 s = 0;
115 else
116 s = (unsigned int)r;
117
118 r = fcntl(fd, F_ADD_SEALS, seals);
119 if (r >= 0) {
120 printf("ADD_SEALS(%d, %u -> %u) didn't fail as expected\n",
121 fd, s, seals);
122 abort();
123 }
124 }
125
mfd_assert_size(int fd,size_t size)126 static void mfd_assert_size(int fd, size_t size)
127 {
128 struct stat st;
129 int r;
130
131 r = fstat(fd, &st);
132 if (r < 0) {
133 printf("fstat(%d) failed: %m\n", fd);
134 abort();
135 } else if (st.st_size != size) {
136 printf("wrong file size %lld, but expected %lld\n",
137 (long long)st.st_size, (long long)size);
138 abort();
139 }
140 }
141
mfd_assert_dup(int fd)142 static int mfd_assert_dup(int fd)
143 {
144 int r;
145
146 r = dup(fd);
147 if (r < 0) {
148 printf("dup(%d) failed: %m\n", fd);
149 abort();
150 }
151
152 return r;
153 }
154
mfd_assert_mmap_shared(int fd)155 static void *mfd_assert_mmap_shared(int fd)
156 {
157 void *p;
158
159 p = mmap(NULL,
160 mfd_def_size,
161 PROT_READ | PROT_WRITE,
162 MAP_SHARED,
163 fd,
164 0);
165 if (p == MAP_FAILED) {
166 printf("mmap() failed: %m\n");
167 abort();
168 }
169
170 return p;
171 }
172
mfd_assert_mmap_private(int fd)173 static void *mfd_assert_mmap_private(int fd)
174 {
175 void *p;
176
177 p = mmap(NULL,
178 mfd_def_size,
179 PROT_READ,
180 MAP_PRIVATE,
181 fd,
182 0);
183 if (p == MAP_FAILED) {
184 printf("mmap() failed: %m\n");
185 abort();
186 }
187
188 return p;
189 }
190
mfd_assert_open(int fd,int flags,mode_t mode)191 static int mfd_assert_open(int fd, int flags, mode_t mode)
192 {
193 char buf[512];
194 int r;
195
196 sprintf(buf, "/proc/self/fd/%d", fd);
197 r = open(buf, flags, mode);
198 if (r < 0) {
199 printf("open(%s) failed: %m\n", buf);
200 abort();
201 }
202
203 return r;
204 }
205
mfd_fail_open(int fd,int flags,mode_t mode)206 static void mfd_fail_open(int fd, int flags, mode_t mode)
207 {
208 char buf[512];
209 int r;
210
211 sprintf(buf, "/proc/self/fd/%d", fd);
212 r = open(buf, flags, mode);
213 if (r >= 0) {
214 printf("open(%s) didn't fail as expected\n", buf);
215 abort();
216 }
217 }
218
mfd_assert_read(int fd)219 static void mfd_assert_read(int fd)
220 {
221 char buf[16];
222 void *p;
223 ssize_t l;
224
225 l = read(fd, buf, sizeof(buf));
226 if (l != sizeof(buf)) {
227 printf("read() failed: %m\n");
228 abort();
229 }
230
231 /* verify PROT_READ *is* allowed */
232 p = mmap(NULL,
233 mfd_def_size,
234 PROT_READ,
235 MAP_PRIVATE,
236 fd,
237 0);
238 if (p == MAP_FAILED) {
239 printf("mmap() failed: %m\n");
240 abort();
241 }
242 munmap(p, mfd_def_size);
243
244 /* verify MAP_PRIVATE is *always* allowed (even writable) */
245 p = mmap(NULL,
246 mfd_def_size,
247 PROT_READ | PROT_WRITE,
248 MAP_PRIVATE,
249 fd,
250 0);
251 if (p == MAP_FAILED) {
252 printf("mmap() failed: %m\n");
253 abort();
254 }
255 munmap(p, mfd_def_size);
256 }
257
mfd_assert_write(int fd)258 static void mfd_assert_write(int fd)
259 {
260 ssize_t l;
261 void *p;
262 int r;
263
264 /*
265 * huegtlbfs does not support write, but we want to
266 * verify everything else here.
267 */
268 if (!hugetlbfs_test) {
269 /* verify write() succeeds */
270 l = write(fd, "\0\0\0\0", 4);
271 if (l != 4) {
272 printf("write() failed: %m\n");
273 abort();
274 }
275 }
276
277 /* verify PROT_READ | PROT_WRITE is allowed */
278 p = mmap(NULL,
279 mfd_def_size,
280 PROT_READ | PROT_WRITE,
281 MAP_SHARED,
282 fd,
283 0);
284 if (p == MAP_FAILED) {
285 printf("mmap() failed: %m\n");
286 abort();
287 }
288 *(char *)p = 0;
289 munmap(p, mfd_def_size);
290
291 /* verify PROT_WRITE is allowed */
292 p = mmap(NULL,
293 mfd_def_size,
294 PROT_WRITE,
295 MAP_SHARED,
296 fd,
297 0);
298 if (p == MAP_FAILED) {
299 printf("mmap() failed: %m\n");
300 abort();
301 }
302 *(char *)p = 0;
303 munmap(p, mfd_def_size);
304
305 /* verify PROT_READ with MAP_SHARED is allowed and a following
306 * mprotect(PROT_WRITE) allows writing */
307 p = mmap(NULL,
308 mfd_def_size,
309 PROT_READ,
310 MAP_SHARED,
311 fd,
312 0);
313 if (p == MAP_FAILED) {
314 printf("mmap() failed: %m\n");
315 abort();
316 }
317
318 r = mprotect(p, mfd_def_size, PROT_READ | PROT_WRITE);
319 if (r < 0) {
320 printf("mprotect() failed: %m\n");
321 abort();
322 }
323
324 *(char *)p = 0;
325 munmap(p, mfd_def_size);
326
327 /* verify PUNCH_HOLE works */
328 r = fallocate(fd,
329 FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
330 0,
331 mfd_def_size);
332 if (r < 0) {
333 printf("fallocate(PUNCH_HOLE) failed: %m\n");
334 abort();
335 }
336 }
337
mfd_fail_write(int fd)338 static void mfd_fail_write(int fd)
339 {
340 ssize_t l;
341 void *p;
342 int r;
343
344 /* verify write() fails */
345 l = write(fd, "data", 4);
346 if (l != -EPERM) {
347 printf("expected EPERM on write(), but got %d: %m\n", (int)l);
348 abort();
349 }
350
351 /* verify PROT_READ | PROT_WRITE is not allowed */
352 p = mmap(NULL,
353 mfd_def_size,
354 PROT_READ | PROT_WRITE,
355 MAP_SHARED,
356 fd,
357 0);
358 if (p != MAP_FAILED) {
359 printf("mmap() didn't fail as expected\n");
360 abort();
361 }
362
363 /* verify PROT_WRITE is not allowed */
364 p = mmap(NULL,
365 mfd_def_size,
366 PROT_WRITE,
367 MAP_SHARED,
368 fd,
369 0);
370 if (p != MAP_FAILED) {
371 printf("mmap() didn't fail as expected\n");
372 abort();
373 }
374
375 /* Verify PROT_READ with MAP_SHARED with a following mprotect is not
376 * allowed. Note that for r/w the kernel already prevents the mmap. */
377 p = mmap(NULL,
378 mfd_def_size,
379 PROT_READ,
380 MAP_SHARED,
381 fd,
382 0);
383 if (p != MAP_FAILED) {
384 r = mprotect(p, mfd_def_size, PROT_READ | PROT_WRITE);
385 if (r >= 0) {
386 printf("mmap()+mprotect() didn't fail as expected\n");
387 abort();
388 }
389 }
390
391 /* verify PUNCH_HOLE fails */
392 r = fallocate(fd,
393 FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
394 0,
395 mfd_def_size);
396 if (r >= 0) {
397 printf("fallocate(PUNCH_HOLE) didn't fail as expected\n");
398 abort();
399 }
400 }
401
mfd_assert_shrink(int fd)402 static void mfd_assert_shrink(int fd)
403 {
404 int r, fd2;
405
406 r = ftruncate(fd, mfd_def_size / 2);
407 if (r < 0) {
408 printf("ftruncate(SHRINK) failed: %m\n");
409 abort();
410 }
411
412 mfd_assert_size(fd, mfd_def_size / 2);
413
414 fd2 = mfd_assert_open(fd,
415 O_RDWR | O_CREAT | O_TRUNC,
416 S_IRUSR | S_IWUSR);
417 close(fd2);
418
419 mfd_assert_size(fd, 0);
420 }
421
mfd_fail_shrink(int fd)422 static void mfd_fail_shrink(int fd)
423 {
424 int r;
425
426 r = ftruncate(fd, mfd_def_size / 2);
427 if (r >= 0) {
428 printf("ftruncate(SHRINK) didn't fail as expected\n");
429 abort();
430 }
431
432 mfd_fail_open(fd,
433 O_RDWR | O_CREAT | O_TRUNC,
434 S_IRUSR | S_IWUSR);
435 }
436
mfd_assert_grow(int fd)437 static void mfd_assert_grow(int fd)
438 {
439 int r;
440
441 r = ftruncate(fd, mfd_def_size * 2);
442 if (r < 0) {
443 printf("ftruncate(GROW) failed: %m\n");
444 abort();
445 }
446
447 mfd_assert_size(fd, mfd_def_size * 2);
448
449 r = fallocate(fd,
450 0,
451 0,
452 mfd_def_size * 4);
453 if (r < 0) {
454 printf("fallocate(ALLOC) failed: %m\n");
455 abort();
456 }
457
458 mfd_assert_size(fd, mfd_def_size * 4);
459 }
460
mfd_fail_grow(int fd)461 static void mfd_fail_grow(int fd)
462 {
463 int r;
464
465 r = ftruncate(fd, mfd_def_size * 2);
466 if (r >= 0) {
467 printf("ftruncate(GROW) didn't fail as expected\n");
468 abort();
469 }
470
471 r = fallocate(fd,
472 0,
473 0,
474 mfd_def_size * 4);
475 if (r >= 0) {
476 printf("fallocate(ALLOC) didn't fail as expected\n");
477 abort();
478 }
479 }
480
mfd_assert_grow_write(int fd)481 static void mfd_assert_grow_write(int fd)
482 {
483 static char *buf;
484 ssize_t l;
485
486 /* hugetlbfs does not support write */
487 if (hugetlbfs_test)
488 return;
489
490 buf = malloc(mfd_def_size * 8);
491 if (!buf) {
492 printf("malloc(%zu) failed: %m\n", mfd_def_size * 8);
493 abort();
494 }
495
496 l = pwrite(fd, buf, mfd_def_size * 8, 0);
497 if (l != (mfd_def_size * 8)) {
498 printf("pwrite() failed: %m\n");
499 abort();
500 }
501
502 mfd_assert_size(fd, mfd_def_size * 8);
503 }
504
mfd_fail_grow_write(int fd)505 static void mfd_fail_grow_write(int fd)
506 {
507 static char *buf;
508 ssize_t l;
509
510 /* hugetlbfs does not support write */
511 if (hugetlbfs_test)
512 return;
513
514 buf = malloc(mfd_def_size * 8);
515 if (!buf) {
516 printf("malloc(%zu) failed: %m\n", mfd_def_size * 8);
517 abort();
518 }
519
520 l = pwrite(fd, buf, mfd_def_size * 8, 0);
521 if (l == (mfd_def_size * 8)) {
522 printf("pwrite() didn't fail as expected\n");
523 abort();
524 }
525 }
526
idle_thread_fn(void * arg)527 static int idle_thread_fn(void *arg)
528 {
529 sigset_t set;
530 int sig;
531
532 /* dummy waiter; SIGTERM terminates us anyway */
533 sigemptyset(&set);
534 sigaddset(&set, SIGTERM);
535 sigwait(&set, &sig);
536
537 return 0;
538 }
539
spawn_idle_thread(unsigned int flags)540 static pid_t spawn_idle_thread(unsigned int flags)
541 {
542 uint8_t *stack;
543 pid_t pid;
544
545 stack = malloc(STACK_SIZE);
546 if (!stack) {
547 printf("malloc(STACK_SIZE) failed: %m\n");
548 abort();
549 }
550
551 pid = clone(idle_thread_fn,
552 stack + STACK_SIZE,
553 SIGCHLD | flags,
554 NULL);
555 if (pid < 0) {
556 printf("clone() failed: %m\n");
557 abort();
558 }
559
560 return pid;
561 }
562
join_idle_thread(pid_t pid)563 static void join_idle_thread(pid_t pid)
564 {
565 kill(pid, SIGTERM);
566 waitpid(pid, NULL, 0);
567 }
568
569 /*
570 * Test memfd_create() syscall
571 * Verify syscall-argument validation, including name checks, flag validation
572 * and more.
573 */
test_create(void)574 static void test_create(void)
575 {
576 char buf[2048];
577 int fd;
578
579 printf("%s CREATE\n", memfd_str);
580
581 /* test NULL name */
582 mfd_fail_new(NULL, 0);
583
584 /* test over-long name (not zero-terminated) */
585 memset(buf, 0xff, sizeof(buf));
586 mfd_fail_new(buf, 0);
587
588 /* test over-long zero-terminated name */
589 memset(buf, 0xff, sizeof(buf));
590 buf[sizeof(buf) - 1] = 0;
591 mfd_fail_new(buf, 0);
592
593 /* verify "" is a valid name */
594 fd = mfd_assert_new("", 0, 0);
595 close(fd);
596
597 /* verify invalid O_* open flags */
598 mfd_fail_new("", 0x0100);
599 mfd_fail_new("", ~MFD_CLOEXEC);
600 mfd_fail_new("", ~MFD_ALLOW_SEALING);
601 mfd_fail_new("", ~0);
602 mfd_fail_new("", 0x80000000U);
603
604 /* verify MFD_CLOEXEC is allowed */
605 fd = mfd_assert_new("", 0, MFD_CLOEXEC);
606 close(fd);
607
608 /* verify MFD_ALLOW_SEALING is allowed */
609 fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING);
610 close(fd);
611
612 /* verify MFD_ALLOW_SEALING | MFD_CLOEXEC is allowed */
613 fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING | MFD_CLOEXEC);
614 close(fd);
615 }
616
617 /*
618 * Test basic sealing
619 * A very basic sealing test to see whether setting/retrieving seals works.
620 */
test_basic(void)621 static void test_basic(void)
622 {
623 int fd;
624
625 printf("%s BASIC\n", memfd_str);
626
627 fd = mfd_assert_new("kern_memfd_basic",
628 mfd_def_size,
629 MFD_CLOEXEC | MFD_ALLOW_SEALING);
630
631 /* add basic seals */
632 mfd_assert_has_seals(fd, 0);
633 mfd_assert_add_seals(fd, F_SEAL_SHRINK |
634 F_SEAL_WRITE);
635 mfd_assert_has_seals(fd, F_SEAL_SHRINK |
636 F_SEAL_WRITE);
637
638 /* add them again */
639 mfd_assert_add_seals(fd, F_SEAL_SHRINK |
640 F_SEAL_WRITE);
641 mfd_assert_has_seals(fd, F_SEAL_SHRINK |
642 F_SEAL_WRITE);
643
644 /* add more seals and seal against sealing */
645 mfd_assert_add_seals(fd, F_SEAL_GROW | F_SEAL_SEAL);
646 mfd_assert_has_seals(fd, F_SEAL_SHRINK |
647 F_SEAL_GROW |
648 F_SEAL_WRITE |
649 F_SEAL_SEAL);
650
651 /* verify that sealing no longer works */
652 mfd_fail_add_seals(fd, F_SEAL_GROW);
653 mfd_fail_add_seals(fd, 0);
654
655 close(fd);
656
657 /* verify sealing does not work without MFD_ALLOW_SEALING */
658 fd = mfd_assert_new("kern_memfd_basic",
659 mfd_def_size,
660 MFD_CLOEXEC);
661 mfd_assert_has_seals(fd, F_SEAL_SEAL);
662 mfd_fail_add_seals(fd, F_SEAL_SHRINK |
663 F_SEAL_GROW |
664 F_SEAL_WRITE);
665 mfd_assert_has_seals(fd, F_SEAL_SEAL);
666 close(fd);
667 }
668
669 /*
670 * Test SEAL_WRITE
671 * Test whether SEAL_WRITE actually prevents modifications.
672 */
test_seal_write(void)673 static void test_seal_write(void)
674 {
675 int fd;
676
677 printf("%s SEAL-WRITE\n", memfd_str);
678
679 fd = mfd_assert_new("kern_memfd_seal_write",
680 mfd_def_size,
681 MFD_CLOEXEC | MFD_ALLOW_SEALING);
682 mfd_assert_has_seals(fd, 0);
683 mfd_assert_add_seals(fd, F_SEAL_WRITE);
684 mfd_assert_has_seals(fd, F_SEAL_WRITE);
685
686 mfd_assert_read(fd);
687 mfd_fail_write(fd);
688 mfd_assert_shrink(fd);
689 mfd_assert_grow(fd);
690 mfd_fail_grow_write(fd);
691
692 close(fd);
693 }
694
695 /*
696 * Test SEAL_SHRINK
697 * Test whether SEAL_SHRINK actually prevents shrinking
698 */
test_seal_shrink(void)699 static void test_seal_shrink(void)
700 {
701 int fd;
702
703 printf("%s SEAL-SHRINK\n", memfd_str);
704
705 fd = mfd_assert_new("kern_memfd_seal_shrink",
706 mfd_def_size,
707 MFD_CLOEXEC | MFD_ALLOW_SEALING);
708 mfd_assert_has_seals(fd, 0);
709 mfd_assert_add_seals(fd, F_SEAL_SHRINK);
710 mfd_assert_has_seals(fd, F_SEAL_SHRINK);
711
712 mfd_assert_read(fd);
713 mfd_assert_write(fd);
714 mfd_fail_shrink(fd);
715 mfd_assert_grow(fd);
716 mfd_assert_grow_write(fd);
717
718 close(fd);
719 }
720
721 /*
722 * Test SEAL_GROW
723 * Test whether SEAL_GROW actually prevents growing
724 */
test_seal_grow(void)725 static void test_seal_grow(void)
726 {
727 int fd;
728
729 printf("%s SEAL-GROW\n", memfd_str);
730
731 fd = mfd_assert_new("kern_memfd_seal_grow",
732 mfd_def_size,
733 MFD_CLOEXEC | MFD_ALLOW_SEALING);
734 mfd_assert_has_seals(fd, 0);
735 mfd_assert_add_seals(fd, F_SEAL_GROW);
736 mfd_assert_has_seals(fd, F_SEAL_GROW);
737
738 mfd_assert_read(fd);
739 mfd_assert_write(fd);
740 mfd_assert_shrink(fd);
741 mfd_fail_grow(fd);
742 mfd_fail_grow_write(fd);
743
744 close(fd);
745 }
746
747 /*
748 * Test SEAL_SHRINK | SEAL_GROW
749 * Test whether SEAL_SHRINK | SEAL_GROW actually prevents resizing
750 */
test_seal_resize(void)751 static void test_seal_resize(void)
752 {
753 int fd;
754
755 printf("%s SEAL-RESIZE\n", memfd_str);
756
757 fd = mfd_assert_new("kern_memfd_seal_resize",
758 mfd_def_size,
759 MFD_CLOEXEC | MFD_ALLOW_SEALING);
760 mfd_assert_has_seals(fd, 0);
761 mfd_assert_add_seals(fd, F_SEAL_SHRINK | F_SEAL_GROW);
762 mfd_assert_has_seals(fd, F_SEAL_SHRINK | F_SEAL_GROW);
763
764 mfd_assert_read(fd);
765 mfd_assert_write(fd);
766 mfd_fail_shrink(fd);
767 mfd_fail_grow(fd);
768 mfd_fail_grow_write(fd);
769
770 close(fd);
771 }
772
773 /*
774 * Test sharing via dup()
775 * Test that seals are shared between dupped FDs and they're all equal.
776 */
test_share_dup(char * banner,char * b_suffix)777 static void test_share_dup(char *banner, char *b_suffix)
778 {
779 int fd, fd2;
780
781 printf("%s %s %s\n", memfd_str, banner, b_suffix);
782
783 fd = mfd_assert_new("kern_memfd_share_dup",
784 mfd_def_size,
785 MFD_CLOEXEC | MFD_ALLOW_SEALING);
786 mfd_assert_has_seals(fd, 0);
787
788 fd2 = mfd_assert_dup(fd);
789 mfd_assert_has_seals(fd2, 0);
790
791 mfd_assert_add_seals(fd, F_SEAL_WRITE);
792 mfd_assert_has_seals(fd, F_SEAL_WRITE);
793 mfd_assert_has_seals(fd2, F_SEAL_WRITE);
794
795 mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
796 mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
797 mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
798
799 mfd_assert_add_seals(fd, F_SEAL_SEAL);
800 mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
801 mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
802
803 mfd_fail_add_seals(fd, F_SEAL_GROW);
804 mfd_fail_add_seals(fd2, F_SEAL_GROW);
805 mfd_fail_add_seals(fd, F_SEAL_SEAL);
806 mfd_fail_add_seals(fd2, F_SEAL_SEAL);
807
808 close(fd2);
809
810 mfd_fail_add_seals(fd, F_SEAL_GROW);
811 close(fd);
812 }
813
814 /*
815 * Test sealing with active mmap()s
816 * Modifying seals is only allowed if no other mmap() refs exist.
817 */
test_share_mmap(char * banner,char * b_suffix)818 static void test_share_mmap(char *banner, char *b_suffix)
819 {
820 int fd;
821 void *p;
822
823 printf("%s %s %s\n", memfd_str, banner, b_suffix);
824
825 fd = mfd_assert_new("kern_memfd_share_mmap",
826 mfd_def_size,
827 MFD_CLOEXEC | MFD_ALLOW_SEALING);
828 mfd_assert_has_seals(fd, 0);
829
830 /* shared/writable ref prevents sealing WRITE, but allows others */
831 p = mfd_assert_mmap_shared(fd);
832 mfd_fail_add_seals(fd, F_SEAL_WRITE);
833 mfd_assert_has_seals(fd, 0);
834 mfd_assert_add_seals(fd, F_SEAL_SHRINK);
835 mfd_assert_has_seals(fd, F_SEAL_SHRINK);
836 munmap(p, mfd_def_size);
837
838 /* readable ref allows sealing */
839 p = mfd_assert_mmap_private(fd);
840 mfd_assert_add_seals(fd, F_SEAL_WRITE);
841 mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
842 munmap(p, mfd_def_size);
843
844 close(fd);
845 }
846
847 /*
848 * Test sealing with open(/proc/self/fd/%d)
849 * Via /proc we can get access to a separate file-context for the same memfd.
850 * This is *not* like dup(), but like a real separate open(). Make sure the
851 * semantics are as expected and we correctly check for RDONLY / WRONLY / RDWR.
852 */
test_share_open(char * banner,char * b_suffix)853 static void test_share_open(char *banner, char *b_suffix)
854 {
855 int fd, fd2;
856
857 printf("%s %s %s\n", memfd_str, banner, b_suffix);
858
859 fd = mfd_assert_new("kern_memfd_share_open",
860 mfd_def_size,
861 MFD_CLOEXEC | MFD_ALLOW_SEALING);
862 mfd_assert_has_seals(fd, 0);
863
864 fd2 = mfd_assert_open(fd, O_RDWR, 0);
865 mfd_assert_add_seals(fd, F_SEAL_WRITE);
866 mfd_assert_has_seals(fd, F_SEAL_WRITE);
867 mfd_assert_has_seals(fd2, F_SEAL_WRITE);
868
869 mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
870 mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
871 mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
872
873 close(fd);
874 fd = mfd_assert_open(fd2, O_RDONLY, 0);
875
876 mfd_fail_add_seals(fd, F_SEAL_SEAL);
877 mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
878 mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
879
880 close(fd2);
881 fd2 = mfd_assert_open(fd, O_RDWR, 0);
882
883 mfd_assert_add_seals(fd2, F_SEAL_SEAL);
884 mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
885 mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
886
887 close(fd2);
888 close(fd);
889 }
890
891 /*
892 * Test sharing via fork()
893 * Test whether seal-modifications work as expected with forked childs.
894 */
test_share_fork(char * banner,char * b_suffix)895 static void test_share_fork(char *banner, char *b_suffix)
896 {
897 int fd;
898 pid_t pid;
899
900 printf("%s %s %s\n", memfd_str, banner, b_suffix);
901
902 fd = mfd_assert_new("kern_memfd_share_fork",
903 mfd_def_size,
904 MFD_CLOEXEC | MFD_ALLOW_SEALING);
905 mfd_assert_has_seals(fd, 0);
906
907 pid = spawn_idle_thread(0);
908 mfd_assert_add_seals(fd, F_SEAL_SEAL);
909 mfd_assert_has_seals(fd, F_SEAL_SEAL);
910
911 mfd_fail_add_seals(fd, F_SEAL_WRITE);
912 mfd_assert_has_seals(fd, F_SEAL_SEAL);
913
914 join_idle_thread(pid);
915
916 mfd_fail_add_seals(fd, F_SEAL_WRITE);
917 mfd_assert_has_seals(fd, F_SEAL_SEAL);
918
919 close(fd);
920 }
921
main(int argc,char ** argv)922 int main(int argc, char **argv)
923 {
924 pid_t pid;
925
926 if (argc == 2) {
927 if (!strcmp(argv[1], "hugetlbfs")) {
928 unsigned long hpage_size = default_huge_page_size();
929
930 if (!hpage_size) {
931 printf("Unable to determine huge page size\n");
932 abort();
933 }
934
935 hugetlbfs_test = 1;
936 memfd_str = MEMFD_HUGE_STR;
937 mfd_def_size = hpage_size * 2;
938 } else {
939 printf("Unknown option: %s\n", argv[1]);
940 abort();
941 }
942 }
943
944 test_create();
945 test_basic();
946
947 test_seal_write();
948 test_seal_shrink();
949 test_seal_grow();
950 test_seal_resize();
951
952 test_share_dup("SHARE-DUP", "");
953 test_share_mmap("SHARE-MMAP", "");
954 test_share_open("SHARE-OPEN", "");
955 test_share_fork("SHARE-FORK", "");
956
957 /* Run test-suite in a multi-threaded environment with a shared
958 * file-table. */
959 pid = spawn_idle_thread(CLONE_FILES | CLONE_FS | CLONE_VM);
960 test_share_dup("SHARE-DUP", SHARED_FT_STR);
961 test_share_mmap("SHARE-MMAP", SHARED_FT_STR);
962 test_share_open("SHARE-OPEN", SHARED_FT_STR);
963 test_share_fork("SHARE-FORK", SHARED_FT_STR);
964 join_idle_thread(pid);
965
966 printf("memfd: DONE\n");
967
968 return 0;
969 }
970