tools/testing/selftests/memfd/memfd_test.c

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