linux/tools/testing/selftests/memfd/memfd_test.c
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   1#define _GNU_SOURCE
   2#define __EXPORTED_HEADERS__
   3
   4#include <errno.h>
   5#include <inttypes.h>
   6#include <limits.h>
   7#include <linux/falloc.h>
   8#include <linux/fcntl.h>
   9#include <linux/memfd.h>
  10#include <sched.h>
  11#include <stdio.h>
  12#include <stdlib.h>
  13#include <signal.h>
  14#include <string.h>
  15#include <sys/mman.h>
  16#include <sys/stat.h>
  17#include <sys/syscall.h>
  18#include <sys/wait.h>
  19#include <unistd.h>
  20
  21#define MFD_DEF_SIZE 8192
  22#define STACK_SIZE 65536
  23
  24static int sys_memfd_create(const char *name,
  25                            unsigned int flags)
  26{
  27        return syscall(__NR_memfd_create, name, flags);
  28}
  29
  30static int mfd_assert_new(const char *name, loff_t sz, unsigned int flags)
  31{
  32        int r, fd;
  33
  34        fd = sys_memfd_create(name, flags);
  35        if (fd < 0) {
  36                printf("memfd_create(\"%s\", %u) failed: %m\n",
  37                       name, flags);
  38                abort();
  39        }
  40
  41        r = ftruncate(fd, sz);
  42        if (r < 0) {
  43                printf("ftruncate(%llu) failed: %m\n", (unsigned long long)sz);
  44                abort();
  45        }
  46
  47        return fd;
  48}
  49
  50static void mfd_fail_new(const char *name, unsigned int flags)
  51{
  52        int r;
  53
  54        r = sys_memfd_create(name, flags);
  55        if (r >= 0) {
  56                printf("memfd_create(\"%s\", %u) succeeded, but failure expected\n",
  57                       name, flags);
  58                close(r);
  59                abort();
  60        }
  61}
  62
  63static unsigned int mfd_assert_get_seals(int fd)
  64{
  65        int r;
  66
  67        r = fcntl(fd, F_GET_SEALS);
  68        if (r < 0) {
  69                printf("GET_SEALS(%d) failed: %m\n", fd);
  70                abort();
  71        }
  72
  73        return (unsigned int)r;
  74}
  75
  76static void mfd_assert_has_seals(int fd, unsigned int seals)
  77{
  78        unsigned int s;
  79
  80        s = mfd_assert_get_seals(fd);
  81        if (s != seals) {
  82                printf("%u != %u = GET_SEALS(%d)\n", seals, s, fd);
  83                abort();
  84        }
  85}
  86
  87static void mfd_assert_add_seals(int fd, unsigned int seals)
  88{
  89        int r;
  90        unsigned int s;
  91
  92        s = mfd_assert_get_seals(fd);
  93        r = fcntl(fd, F_ADD_SEALS, seals);
  94        if (r < 0) {
  95                printf("ADD_SEALS(%d, %u -> %u) failed: %m\n", fd, s, seals);
  96                abort();
  97        }
  98}
  99
 100static void mfd_fail_add_seals(int fd, unsigned int seals)
 101{
 102        int r;
 103        unsigned int s;
 104
 105        r = fcntl(fd, F_GET_SEALS);
 106        if (r < 0)
 107                s = 0;
 108        else
 109                s = (unsigned int)r;
 110
 111        r = fcntl(fd, F_ADD_SEALS, seals);
 112        if (r >= 0) {
 113                printf("ADD_SEALS(%d, %u -> %u) didn't fail as expected\n",
 114                                fd, s, seals);
 115                abort();
 116        }
 117}
 118
 119static void mfd_assert_size(int fd, size_t size)
 120{
 121        struct stat st;
 122        int r;
 123
 124        r = fstat(fd, &st);
 125        if (r < 0) {
 126                printf("fstat(%d) failed: %m\n", fd);
 127                abort();
 128        } else if (st.st_size != size) {
 129                printf("wrong file size %lld, but expected %lld\n",
 130                       (long long)st.st_size, (long long)size);
 131                abort();
 132        }
 133}
 134
 135static int mfd_assert_dup(int fd)
 136{
 137        int r;
 138
 139        r = dup(fd);
 140        if (r < 0) {
 141                printf("dup(%d) failed: %m\n", fd);
 142                abort();
 143        }
 144
 145        return r;
 146}
 147
 148static void *mfd_assert_mmap_shared(int fd)
 149{
 150        void *p;
 151
 152        p = mmap(NULL,
 153                 MFD_DEF_SIZE,
 154                 PROT_READ | PROT_WRITE,
 155                 MAP_SHARED,
 156                 fd,
 157                 0);
 158        if (p == MAP_FAILED) {
 159                printf("mmap() failed: %m\n");
 160                abort();
 161        }
 162
 163        return p;
 164}
 165
 166static void *mfd_assert_mmap_private(int fd)
 167{
 168        void *p;
 169
 170        p = mmap(NULL,
 171                 MFD_DEF_SIZE,
 172                 PROT_READ,
 173                 MAP_PRIVATE,
 174                 fd,
 175                 0);
 176        if (p == MAP_FAILED) {
 177                printf("mmap() failed: %m\n");
 178                abort();
 179        }
 180
 181        return p;
 182}
 183
 184static int mfd_assert_open(int fd, int flags, mode_t mode)
 185{
 186        char buf[512];
 187        int r;
 188
 189        sprintf(buf, "/proc/self/fd/%d", fd);
 190        r = open(buf, flags, mode);
 191        if (r < 0) {
 192                printf("open(%s) failed: %m\n", buf);
 193                abort();
 194        }
 195
 196        return r;
 197}
 198
 199static void mfd_fail_open(int fd, int flags, mode_t mode)
 200{
 201        char buf[512];
 202        int r;
 203
 204        sprintf(buf, "/proc/self/fd/%d", fd);
 205        r = open(buf, flags, mode);
 206        if (r >= 0) {
 207                printf("open(%s) didn't fail as expected\n", buf);
 208                abort();
 209        }
 210}
 211
 212static void mfd_assert_read(int fd)
 213{
 214        char buf[16];
 215        void *p;
 216        ssize_t l;
 217
 218        l = read(fd, buf, sizeof(buf));
 219        if (l != sizeof(buf)) {
 220                printf("read() failed: %m\n");
 221                abort();
 222        }
 223
 224        /* verify PROT_READ *is* allowed */
 225        p = mmap(NULL,
 226                 MFD_DEF_SIZE,
 227                 PROT_READ,
 228                 MAP_PRIVATE,
 229                 fd,
 230                 0);
 231        if (p == MAP_FAILED) {
 232                printf("mmap() failed: %m\n");
 233                abort();
 234        }
 235        munmap(p, MFD_DEF_SIZE);
 236
 237        /* verify MAP_PRIVATE is *always* allowed (even writable) */
 238        p = mmap(NULL,
 239                 MFD_DEF_SIZE,
 240                 PROT_READ | PROT_WRITE,
 241                 MAP_PRIVATE,
 242                 fd,
 243                 0);
 244        if (p == MAP_FAILED) {
 245                printf("mmap() failed: %m\n");
 246                abort();
 247        }
 248        munmap(p, MFD_DEF_SIZE);
 249}
 250
 251static void mfd_assert_write(int fd)
 252{
 253        ssize_t l;
 254        void *p;
 255        int r;
 256
 257        /* verify write() succeeds */
 258        l = write(fd, "\0\0\0\0", 4);
 259        if (l != 4) {
 260                printf("write() failed: %m\n");
 261                abort();
 262        }
 263
 264        /* verify PROT_READ | PROT_WRITE is allowed */
 265        p = mmap(NULL,
 266                 MFD_DEF_SIZE,
 267                 PROT_READ | PROT_WRITE,
 268                 MAP_SHARED,
 269                 fd,
 270                 0);
 271        if (p == MAP_FAILED) {
 272                printf("mmap() failed: %m\n");
 273                abort();
 274        }
 275        *(char *)p = 0;
 276        munmap(p, MFD_DEF_SIZE);
 277
 278        /* verify PROT_WRITE is allowed */
 279        p = mmap(NULL,
 280                 MFD_DEF_SIZE,
 281                 PROT_WRITE,
 282                 MAP_SHARED,
 283                 fd,
 284                 0);
 285        if (p == MAP_FAILED) {
 286                printf("mmap() failed: %m\n");
 287                abort();
 288        }
 289        *(char *)p = 0;
 290        munmap(p, MFD_DEF_SIZE);
 291
 292        /* verify PROT_READ with MAP_SHARED is allowed and a following
 293         * mprotect(PROT_WRITE) allows writing */
 294        p = mmap(NULL,
 295                 MFD_DEF_SIZE,
 296                 PROT_READ,
 297                 MAP_SHARED,
 298                 fd,
 299                 0);
 300        if (p == MAP_FAILED) {
 301                printf("mmap() failed: %m\n");
 302                abort();
 303        }
 304
 305        r = mprotect(p, MFD_DEF_SIZE, PROT_READ | PROT_WRITE);
 306        if (r < 0) {
 307                printf("mprotect() failed: %m\n");
 308                abort();
 309        }
 310
 311        *(char *)p = 0;
 312        munmap(p, MFD_DEF_SIZE);
 313
 314        /* verify PUNCH_HOLE works */
 315        r = fallocate(fd,
 316                      FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
 317                      0,
 318                      MFD_DEF_SIZE);
 319        if (r < 0) {
 320                printf("fallocate(PUNCH_HOLE) failed: %m\n");
 321                abort();
 322        }
 323}
 324
 325static void mfd_fail_write(int fd)
 326{
 327        ssize_t l;
 328        void *p;
 329        int r;
 330
 331        /* verify write() fails */
 332        l = write(fd, "data", 4);
 333        if (l != -EPERM) {
 334                printf("expected EPERM on write(), but got %d: %m\n", (int)l);
 335                abort();
 336        }
 337
 338        /* verify PROT_READ | PROT_WRITE is not allowed */
 339        p = mmap(NULL,
 340                 MFD_DEF_SIZE,
 341                 PROT_READ | PROT_WRITE,
 342                 MAP_SHARED,
 343                 fd,
 344                 0);
 345        if (p != MAP_FAILED) {
 346                printf("mmap() didn't fail as expected\n");
 347                abort();
 348        }
 349
 350        /* verify PROT_WRITE is not allowed */
 351        p = mmap(NULL,
 352                 MFD_DEF_SIZE,
 353                 PROT_WRITE,
 354                 MAP_SHARED,
 355                 fd,
 356                 0);
 357        if (p != MAP_FAILED) {
 358                printf("mmap() didn't fail as expected\n");
 359                abort();
 360        }
 361
 362        /* Verify PROT_READ with MAP_SHARED with a following mprotect is not
 363         * allowed. Note that for r/w the kernel already prevents the mmap. */
 364        p = mmap(NULL,
 365                 MFD_DEF_SIZE,
 366                 PROT_READ,
 367                 MAP_SHARED,
 368                 fd,
 369                 0);
 370        if (p != MAP_FAILED) {
 371                r = mprotect(p, MFD_DEF_SIZE, PROT_READ | PROT_WRITE);
 372                if (r >= 0) {
 373                        printf("mmap()+mprotect() didn't fail as expected\n");
 374                        abort();
 375                }
 376        }
 377
 378        /* verify PUNCH_HOLE fails */
 379        r = fallocate(fd,
 380                      FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
 381                      0,
 382                      MFD_DEF_SIZE);
 383        if (r >= 0) {
 384                printf("fallocate(PUNCH_HOLE) didn't fail as expected\n");
 385                abort();
 386        }
 387}
 388
 389static void mfd_assert_shrink(int fd)
 390{
 391        int r, fd2;
 392
 393        r = ftruncate(fd, MFD_DEF_SIZE / 2);
 394        if (r < 0) {
 395                printf("ftruncate(SHRINK) failed: %m\n");
 396                abort();
 397        }
 398
 399        mfd_assert_size(fd, MFD_DEF_SIZE / 2);
 400
 401        fd2 = mfd_assert_open(fd,
 402                              O_RDWR | O_CREAT | O_TRUNC,
 403                              S_IRUSR | S_IWUSR);
 404        close(fd2);
 405
 406        mfd_assert_size(fd, 0);
 407}
 408
 409static void mfd_fail_shrink(int fd)
 410{
 411        int r;
 412
 413        r = ftruncate(fd, MFD_DEF_SIZE / 2);
 414        if (r >= 0) {
 415                printf("ftruncate(SHRINK) didn't fail as expected\n");
 416                abort();
 417        }
 418
 419        mfd_fail_open(fd,
 420                      O_RDWR | O_CREAT | O_TRUNC,
 421                      S_IRUSR | S_IWUSR);
 422}
 423
 424static void mfd_assert_grow(int fd)
 425{
 426        int r;
 427
 428        r = ftruncate(fd, MFD_DEF_SIZE * 2);
 429        if (r < 0) {
 430                printf("ftruncate(GROW) failed: %m\n");
 431                abort();
 432        }
 433
 434        mfd_assert_size(fd, MFD_DEF_SIZE * 2);
 435
 436        r = fallocate(fd,
 437                      0,
 438                      0,
 439                      MFD_DEF_SIZE * 4);
 440        if (r < 0) {
 441                printf("fallocate(ALLOC) failed: %m\n");
 442                abort();
 443        }
 444
 445        mfd_assert_size(fd, MFD_DEF_SIZE * 4);
 446}
 447
 448static void mfd_fail_grow(int fd)
 449{
 450        int r;
 451
 452        r = ftruncate(fd, MFD_DEF_SIZE * 2);
 453        if (r >= 0) {
 454                printf("ftruncate(GROW) didn't fail as expected\n");
 455                abort();
 456        }
 457
 458        r = fallocate(fd,
 459                      0,
 460                      0,
 461                      MFD_DEF_SIZE * 4);
 462        if (r >= 0) {
 463                printf("fallocate(ALLOC) didn't fail as expected\n");
 464                abort();
 465        }
 466}
 467
 468static void mfd_assert_grow_write(int fd)
 469{
 470        static char buf[MFD_DEF_SIZE * 8];
 471        ssize_t l;
 472
 473        l = pwrite(fd, buf, sizeof(buf), 0);
 474        if (l != sizeof(buf)) {
 475                printf("pwrite() failed: %m\n");
 476                abort();
 477        }
 478
 479        mfd_assert_size(fd, MFD_DEF_SIZE * 8);
 480}
 481
 482static void mfd_fail_grow_write(int fd)
 483{
 484        static char buf[MFD_DEF_SIZE * 8];
 485        ssize_t l;
 486
 487        l = pwrite(fd, buf, sizeof(buf), 0);
 488        if (l == sizeof(buf)) {
 489                printf("pwrite() didn't fail as expected\n");
 490                abort();
 491        }
 492}
 493
 494static int idle_thread_fn(void *arg)
 495{
 496        sigset_t set;
 497        int sig;
 498
 499        /* dummy waiter; SIGTERM terminates us anyway */
 500        sigemptyset(&set);
 501        sigaddset(&set, SIGTERM);
 502        sigwait(&set, &sig);
 503
 504        return 0;
 505}
 506
 507static pid_t spawn_idle_thread(unsigned int flags)
 508{
 509        uint8_t *stack;
 510        pid_t pid;
 511
 512        stack = malloc(STACK_SIZE);
 513        if (!stack) {
 514                printf("malloc(STACK_SIZE) failed: %m\n");
 515                abort();
 516        }
 517
 518        pid = clone(idle_thread_fn,
 519                    stack + STACK_SIZE,
 520                    SIGCHLD | flags,
 521                    NULL);
 522        if (pid < 0) {
 523                printf("clone() failed: %m\n");
 524                abort();
 525        }
 526
 527        return pid;
 528}
 529
 530static void join_idle_thread(pid_t pid)
 531{
 532        kill(pid, SIGTERM);
 533        waitpid(pid, NULL, 0);
 534}
 535
 536/*
 537 * Test memfd_create() syscall
 538 * Verify syscall-argument validation, including name checks, flag validation
 539 * and more.
 540 */
 541static void test_create(void)
 542{
 543        char buf[2048];
 544        int fd;
 545
 546        /* test NULL name */
 547        mfd_fail_new(NULL, 0);
 548
 549        /* test over-long name (not zero-terminated) */
 550        memset(buf, 0xff, sizeof(buf));
 551        mfd_fail_new(buf, 0);
 552
 553        /* test over-long zero-terminated name */
 554        memset(buf, 0xff, sizeof(buf));
 555        buf[sizeof(buf) - 1] = 0;
 556        mfd_fail_new(buf, 0);
 557
 558        /* verify "" is a valid name */
 559        fd = mfd_assert_new("", 0, 0);
 560        close(fd);
 561
 562        /* verify invalid O_* open flags */
 563        mfd_fail_new("", 0x0100);
 564        mfd_fail_new("", ~MFD_CLOEXEC);
 565        mfd_fail_new("", ~MFD_ALLOW_SEALING);
 566        mfd_fail_new("", ~0);
 567        mfd_fail_new("", 0x80000000U);
 568
 569        /* verify MFD_CLOEXEC is allowed */
 570        fd = mfd_assert_new("", 0, MFD_CLOEXEC);
 571        close(fd);
 572
 573        /* verify MFD_ALLOW_SEALING is allowed */
 574        fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING);
 575        close(fd);
 576
 577        /* verify MFD_ALLOW_SEALING | MFD_CLOEXEC is allowed */
 578        fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING | MFD_CLOEXEC);
 579        close(fd);
 580}
 581
 582/*
 583 * Test basic sealing
 584 * A very basic sealing test to see whether setting/retrieving seals works.
 585 */
 586static void test_basic(void)
 587{
 588        int fd;
 589
 590        fd = mfd_assert_new("kern_memfd_basic",
 591                            MFD_DEF_SIZE,
 592                            MFD_CLOEXEC | MFD_ALLOW_SEALING);
 593
 594        /* add basic seals */
 595        mfd_assert_has_seals(fd, 0);
 596        mfd_assert_add_seals(fd, F_SEAL_SHRINK |
 597                                 F_SEAL_WRITE);
 598        mfd_assert_has_seals(fd, F_SEAL_SHRINK |
 599                                 F_SEAL_WRITE);
 600
 601        /* add them again */
 602        mfd_assert_add_seals(fd, F_SEAL_SHRINK |
 603                                 F_SEAL_WRITE);
 604        mfd_assert_has_seals(fd, F_SEAL_SHRINK |
 605                                 F_SEAL_WRITE);
 606
 607        /* add more seals and seal against sealing */
 608        mfd_assert_add_seals(fd, F_SEAL_GROW | F_SEAL_SEAL);
 609        mfd_assert_has_seals(fd, F_SEAL_SHRINK |
 610                                 F_SEAL_GROW |
 611                                 F_SEAL_WRITE |
 612                                 F_SEAL_SEAL);
 613
 614        /* verify that sealing no longer works */
 615        mfd_fail_add_seals(fd, F_SEAL_GROW);
 616        mfd_fail_add_seals(fd, 0);
 617
 618        close(fd);
 619
 620        /* verify sealing does not work without MFD_ALLOW_SEALING */
 621        fd = mfd_assert_new("kern_memfd_basic",
 622                            MFD_DEF_SIZE,
 623                            MFD_CLOEXEC);
 624        mfd_assert_has_seals(fd, F_SEAL_SEAL);
 625        mfd_fail_add_seals(fd, F_SEAL_SHRINK |
 626                               F_SEAL_GROW |
 627                               F_SEAL_WRITE);
 628        mfd_assert_has_seals(fd, F_SEAL_SEAL);
 629        close(fd);
 630}
 631
 632/*
 633 * Test SEAL_WRITE
 634 * Test whether SEAL_WRITE actually prevents modifications.
 635 */
 636static void test_seal_write(void)
 637{
 638        int fd;
 639
 640        fd = mfd_assert_new("kern_memfd_seal_write",
 641                            MFD_DEF_SIZE,
 642                            MFD_CLOEXEC | MFD_ALLOW_SEALING);
 643        mfd_assert_has_seals(fd, 0);
 644        mfd_assert_add_seals(fd, F_SEAL_WRITE);
 645        mfd_assert_has_seals(fd, F_SEAL_WRITE);
 646
 647        mfd_assert_read(fd);
 648        mfd_fail_write(fd);
 649        mfd_assert_shrink(fd);
 650        mfd_assert_grow(fd);
 651        mfd_fail_grow_write(fd);
 652
 653        close(fd);
 654}
 655
 656/*
 657 * Test SEAL_SHRINK
 658 * Test whether SEAL_SHRINK actually prevents shrinking
 659 */
 660static void test_seal_shrink(void)
 661{
 662        int fd;
 663
 664        fd = mfd_assert_new("kern_memfd_seal_shrink",
 665                            MFD_DEF_SIZE,
 666                            MFD_CLOEXEC | MFD_ALLOW_SEALING);
 667        mfd_assert_has_seals(fd, 0);
 668        mfd_assert_add_seals(fd, F_SEAL_SHRINK);
 669        mfd_assert_has_seals(fd, F_SEAL_SHRINK);
 670
 671        mfd_assert_read(fd);
 672        mfd_assert_write(fd);
 673        mfd_fail_shrink(fd);
 674        mfd_assert_grow(fd);
 675        mfd_assert_grow_write(fd);
 676
 677        close(fd);
 678}
 679
 680/*
 681 * Test SEAL_GROW
 682 * Test whether SEAL_GROW actually prevents growing
 683 */
 684static void test_seal_grow(void)
 685{
 686        int fd;
 687
 688        fd = mfd_assert_new("kern_memfd_seal_grow",
 689                            MFD_DEF_SIZE,
 690                            MFD_CLOEXEC | MFD_ALLOW_SEALING);
 691        mfd_assert_has_seals(fd, 0);
 692        mfd_assert_add_seals(fd, F_SEAL_GROW);
 693        mfd_assert_has_seals(fd, F_SEAL_GROW);
 694
 695        mfd_assert_read(fd);
 696        mfd_assert_write(fd);
 697        mfd_assert_shrink(fd);
 698        mfd_fail_grow(fd);
 699        mfd_fail_grow_write(fd);
 700
 701        close(fd);
 702}
 703
 704/*
 705 * Test SEAL_SHRINK | SEAL_GROW
 706 * Test whether SEAL_SHRINK | SEAL_GROW actually prevents resizing
 707 */
 708static void test_seal_resize(void)
 709{
 710        int fd;
 711
 712        fd = mfd_assert_new("kern_memfd_seal_resize",
 713                            MFD_DEF_SIZE,
 714                            MFD_CLOEXEC | MFD_ALLOW_SEALING);
 715        mfd_assert_has_seals(fd, 0);
 716        mfd_assert_add_seals(fd, F_SEAL_SHRINK | F_SEAL_GROW);
 717        mfd_assert_has_seals(fd, F_SEAL_SHRINK | F_SEAL_GROW);
 718
 719        mfd_assert_read(fd);
 720        mfd_assert_write(fd);
 721        mfd_fail_shrink(fd);
 722        mfd_fail_grow(fd);
 723        mfd_fail_grow_write(fd);
 724
 725        close(fd);
 726}
 727
 728/*
 729 * Test sharing via dup()
 730 * Test that seals are shared between dupped FDs and they're all equal.
 731 */
 732static void test_share_dup(void)
 733{
 734        int fd, fd2;
 735
 736        fd = mfd_assert_new("kern_memfd_share_dup",
 737                            MFD_DEF_SIZE,
 738                            MFD_CLOEXEC | MFD_ALLOW_SEALING);
 739        mfd_assert_has_seals(fd, 0);
 740
 741        fd2 = mfd_assert_dup(fd);
 742        mfd_assert_has_seals(fd2, 0);
 743
 744        mfd_assert_add_seals(fd, F_SEAL_WRITE);
 745        mfd_assert_has_seals(fd, F_SEAL_WRITE);
 746        mfd_assert_has_seals(fd2, F_SEAL_WRITE);
 747
 748        mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
 749        mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
 750        mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
 751
 752        mfd_assert_add_seals(fd, F_SEAL_SEAL);
 753        mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
 754        mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
 755
 756        mfd_fail_add_seals(fd, F_SEAL_GROW);
 757        mfd_fail_add_seals(fd2, F_SEAL_GROW);
 758        mfd_fail_add_seals(fd, F_SEAL_SEAL);
 759        mfd_fail_add_seals(fd2, F_SEAL_SEAL);
 760
 761        close(fd2);
 762
 763        mfd_fail_add_seals(fd, F_SEAL_GROW);
 764        close(fd);
 765}
 766
 767/*
 768 * Test sealing with active mmap()s
 769 * Modifying seals is only allowed if no other mmap() refs exist.
 770 */
 771static void test_share_mmap(void)
 772{
 773        int fd;
 774        void *p;
 775
 776        fd = mfd_assert_new("kern_memfd_share_mmap",
 777                            MFD_DEF_SIZE,
 778                            MFD_CLOEXEC | MFD_ALLOW_SEALING);
 779        mfd_assert_has_seals(fd, 0);
 780
 781        /* shared/writable ref prevents sealing WRITE, but allows others */
 782        p = mfd_assert_mmap_shared(fd);
 783        mfd_fail_add_seals(fd, F_SEAL_WRITE);
 784        mfd_assert_has_seals(fd, 0);
 785        mfd_assert_add_seals(fd, F_SEAL_SHRINK);
 786        mfd_assert_has_seals(fd, F_SEAL_SHRINK);
 787        munmap(p, MFD_DEF_SIZE);
 788
 789        /* readable ref allows sealing */
 790        p = mfd_assert_mmap_private(fd);
 791        mfd_assert_add_seals(fd, F_SEAL_WRITE);
 792        mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
 793        munmap(p, MFD_DEF_SIZE);
 794
 795        close(fd);
 796}
 797
 798/*
 799 * Test sealing with open(/proc/self/fd/%d)
 800 * Via /proc we can get access to a separate file-context for the same memfd.
 801 * This is *not* like dup(), but like a real separate open(). Make sure the
 802 * semantics are as expected and we correctly check for RDONLY / WRONLY / RDWR.
 803 */
 804static void test_share_open(void)
 805{
 806        int fd, fd2;
 807
 808        fd = mfd_assert_new("kern_memfd_share_open",
 809                            MFD_DEF_SIZE,
 810                            MFD_CLOEXEC | MFD_ALLOW_SEALING);
 811        mfd_assert_has_seals(fd, 0);
 812
 813        fd2 = mfd_assert_open(fd, O_RDWR, 0);
 814        mfd_assert_add_seals(fd, F_SEAL_WRITE);
 815        mfd_assert_has_seals(fd, F_SEAL_WRITE);
 816        mfd_assert_has_seals(fd2, F_SEAL_WRITE);
 817
 818        mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
 819        mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
 820        mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
 821
 822        close(fd);
 823        fd = mfd_assert_open(fd2, O_RDONLY, 0);
 824
 825        mfd_fail_add_seals(fd, F_SEAL_SEAL);
 826        mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
 827        mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
 828
 829        close(fd2);
 830        fd2 = mfd_assert_open(fd, O_RDWR, 0);
 831
 832        mfd_assert_add_seals(fd2, F_SEAL_SEAL);
 833        mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
 834        mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
 835
 836        close(fd2);
 837        close(fd);
 838}
 839
 840/*
 841 * Test sharing via fork()
 842 * Test whether seal-modifications work as expected with forked childs.
 843 */
 844static void test_share_fork(void)
 845{
 846        int fd;
 847        pid_t pid;
 848
 849        fd = mfd_assert_new("kern_memfd_share_fork",
 850                            MFD_DEF_SIZE,
 851                            MFD_CLOEXEC | MFD_ALLOW_SEALING);
 852        mfd_assert_has_seals(fd, 0);
 853
 854        pid = spawn_idle_thread(0);
 855        mfd_assert_add_seals(fd, F_SEAL_SEAL);
 856        mfd_assert_has_seals(fd, F_SEAL_SEAL);
 857
 858        mfd_fail_add_seals(fd, F_SEAL_WRITE);
 859        mfd_assert_has_seals(fd, F_SEAL_SEAL);
 860
 861        join_idle_thread(pid);
 862
 863        mfd_fail_add_seals(fd, F_SEAL_WRITE);
 864        mfd_assert_has_seals(fd, F_SEAL_SEAL);
 865
 866        close(fd);
 867}
 868
 869int main(int argc, char **argv)
 870{
 871        pid_t pid;
 872
 873        printf("memfd: CREATE\n");
 874        test_create();
 875        printf("memfd: BASIC\n");
 876        test_basic();
 877
 878        printf("memfd: SEAL-WRITE\n");
 879        test_seal_write();
 880        printf("memfd: SEAL-SHRINK\n");
 881        test_seal_shrink();
 882        printf("memfd: SEAL-GROW\n");
 883        test_seal_grow();
 884        printf("memfd: SEAL-RESIZE\n");
 885        test_seal_resize();
 886
 887        printf("memfd: SHARE-DUP\n");
 888        test_share_dup();
 889        printf("memfd: SHARE-MMAP\n");
 890        test_share_mmap();
 891        printf("memfd: SHARE-OPEN\n");
 892        test_share_open();
 893        printf("memfd: SHARE-FORK\n");
 894        test_share_fork();
 895
 896        /* Run test-suite in a multi-threaded environment with a shared
 897         * file-table. */
 898        pid = spawn_idle_thread(CLONE_FILES | CLONE_FS | CLONE_VM);
 899        printf("memfd: SHARE-DUP (shared file-table)\n");
 900        test_share_dup();
 901        printf("memfd: SHARE-MMAP (shared file-table)\n");
 902        test_share_mmap();
 903        printf("memfd: SHARE-OPEN (shared file-table)\n");
 904        test_share_open();
 905        printf("memfd: SHARE-FORK (shared file-table)\n");
 906        test_share_fork();
 907        join_idle_thread(pid);
 908
 909        printf("memfd: DONE\n");
 910
 911        return 0;
 912}
 913