1 /* 2 * Copyright (c) 2012 The Chromium OS Authors. All rights reserved. 3 * Use of this source code is governed by the GPLv2 license. 4 * 5 * Test code for seccomp bpf. 6 */ 7 8 #include <sys/types.h> 9 10 /* 11 * glibc 2.26 and later have SIGSYS in siginfo_t. Before that, 12 * we need to use the kernel's siginfo.h file and trick glibc 13 * into accepting it. 14 */ 15 #if !__GLIBC_PREREQ(2, 26) 16 # include <asm/siginfo.h> 17 # define __have_siginfo_t 1 18 # define __have_sigval_t 1 19 # define __have_sigevent_t 1 20 #endif 21 22 #include <errno.h> 23 #include <linux/filter.h> 24 #include <sys/prctl.h> 25 #include <sys/ptrace.h> 26 #include <sys/user.h> 27 #include <linux/prctl.h> 28 #include <linux/ptrace.h> 29 #include <linux/seccomp.h> 30 #include <pthread.h> 31 #include <semaphore.h> 32 #include <signal.h> 33 #include <stddef.h> 34 #include <stdbool.h> 35 #include <string.h> 36 #include <time.h> 37 #include <linux/elf.h> 38 #include <sys/uio.h> 39 #include <sys/utsname.h> 40 #include <sys/fcntl.h> 41 #include <sys/mman.h> 42 #include <sys/times.h> 43 44 #define _GNU_SOURCE 45 #include <unistd.h> 46 #include <sys/syscall.h> 47 48 #include "../kselftest_harness.h" 49 50 #ifndef PR_SET_PTRACER 51 # define PR_SET_PTRACER 0x59616d61 52 #endif 53 54 #ifndef PR_SET_NO_NEW_PRIVS 55 #define PR_SET_NO_NEW_PRIVS 38 56 #define PR_GET_NO_NEW_PRIVS 39 57 #endif 58 59 #ifndef PR_SECCOMP_EXT 60 #define PR_SECCOMP_EXT 43 61 #endif 62 63 #ifndef SECCOMP_EXT_ACT 64 #define SECCOMP_EXT_ACT 1 65 #endif 66 67 #ifndef SECCOMP_EXT_ACT_TSYNC 68 #define SECCOMP_EXT_ACT_TSYNC 1 69 #endif 70 71 #ifndef SECCOMP_MODE_STRICT 72 #define SECCOMP_MODE_STRICT 1 73 #endif 74 75 #ifndef SECCOMP_MODE_FILTER 76 #define SECCOMP_MODE_FILTER 2 77 #endif 78 79 #ifndef SECCOMP_RET_ALLOW 80 struct seccomp_data { 81 int nr; 82 __u32 arch; 83 __u64 instruction_pointer; 84 __u64 args[6]; 85 }; 86 #endif 87 88 #ifndef SECCOMP_RET_KILL_PROCESS 89 #define SECCOMP_RET_KILL_PROCESS 0x80000000U /* kill the process */ 90 #define SECCOMP_RET_KILL_THREAD 0x00000000U /* kill the thread */ 91 #endif 92 #ifndef SECCOMP_RET_KILL 93 #define SECCOMP_RET_KILL SECCOMP_RET_KILL_THREAD 94 #define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */ 95 #define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */ 96 #define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */ 97 #define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */ 98 #endif 99 #ifndef SECCOMP_RET_LOG 100 #define SECCOMP_RET_LOG 0x7ffc0000U /* allow after logging */ 101 #endif 102 103 #ifndef __NR_seccomp 104 # if defined(__i386__) 105 # define __NR_seccomp 354 106 # elif defined(__x86_64__) 107 # define __NR_seccomp 317 108 # elif defined(__arm__) 109 # define __NR_seccomp 383 110 # elif defined(__aarch64__) 111 # define __NR_seccomp 277 112 # elif defined(__hppa__) 113 # define __NR_seccomp 338 114 # elif defined(__powerpc__) 115 # define __NR_seccomp 358 116 # elif defined(__s390__) 117 # define __NR_seccomp 348 118 # else 119 # warning "seccomp syscall number unknown for this architecture" 120 # define __NR_seccomp 0xffff 121 # endif 122 #endif 123 124 #ifndef SECCOMP_SET_MODE_STRICT 125 #define SECCOMP_SET_MODE_STRICT 0 126 #endif 127 128 #ifndef SECCOMP_SET_MODE_FILTER 129 #define SECCOMP_SET_MODE_FILTER 1 130 #endif 131 132 #ifndef SECCOMP_GET_ACTION_AVAIL 133 #define SECCOMP_GET_ACTION_AVAIL 2 134 #endif 135 136 #ifndef SECCOMP_FILTER_FLAG_TSYNC 137 #define SECCOMP_FILTER_FLAG_TSYNC (1UL << 0) 138 #endif 139 140 #ifndef SECCOMP_FILTER_FLAG_LOG 141 #define SECCOMP_FILTER_FLAG_LOG (1UL << 1) 142 #endif 143 144 #ifndef SECCOMP_FILTER_FLAG_SPEC_ALLOW 145 #define SECCOMP_FILTER_FLAG_SPEC_ALLOW (1UL << 2) 146 #endif 147 148 #ifndef PTRACE_SECCOMP_GET_METADATA 149 #define PTRACE_SECCOMP_GET_METADATA 0x420d 150 151 struct seccomp_metadata { 152 __u64 filter_off; /* Input: which filter */ 153 __u64 flags; /* Output: filter's flags */ 154 }; 155 #endif 156 157 #ifndef seccomp 158 int seccomp(unsigned int op, unsigned int flags, void *args) 159 { 160 errno = 0; 161 return syscall(__NR_seccomp, op, flags, args); 162 } 163 #endif 164 165 #if __BYTE_ORDER == __LITTLE_ENDIAN 166 #define syscall_arg(_n) (offsetof(struct seccomp_data, args[_n])) 167 #elif __BYTE_ORDER == __BIG_ENDIAN 168 #define syscall_arg(_n) (offsetof(struct seccomp_data, args[_n]) + sizeof(__u32)) 169 #else 170 #error "wut? Unknown __BYTE_ORDER?!" 171 #endif 172 173 #define SIBLING_EXIT_UNKILLED 0xbadbeef 174 #define SIBLING_EXIT_FAILURE 0xbadface 175 #define SIBLING_EXIT_NEWPRIVS 0xbadfeed 176 177 TEST(mode_strict_support) 178 { 179 long ret; 180 181 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT, NULL, NULL, NULL); 182 ASSERT_EQ(0, ret) { 183 TH_LOG("Kernel does not support CONFIG_SECCOMP"); 184 } 185 syscall(__NR_exit, 0); 186 } 187 188 TEST_SIGNAL(mode_strict_cannot_call_prctl, SIGKILL) 189 { 190 long ret; 191 192 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT, NULL, NULL, NULL); 193 ASSERT_EQ(0, ret) { 194 TH_LOG("Kernel does not support CONFIG_SECCOMP"); 195 } 196 syscall(__NR_prctl, PR_SET_SECCOMP, SECCOMP_MODE_FILTER, 197 NULL, NULL, NULL); 198 EXPECT_FALSE(true) { 199 TH_LOG("Unreachable!"); 200 } 201 } 202 203 /* Note! This doesn't test no new privs behavior */ 204 TEST(no_new_privs_support) 205 { 206 long ret; 207 208 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 209 EXPECT_EQ(0, ret) { 210 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 211 } 212 } 213 214 /* Tests kernel support by checking for a copy_from_user() fault on NULL. */ 215 TEST(mode_filter_support) 216 { 217 long ret; 218 219 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, NULL, 0, 0); 220 ASSERT_EQ(0, ret) { 221 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 222 } 223 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, NULL, NULL, NULL); 224 EXPECT_EQ(-1, ret); 225 EXPECT_EQ(EFAULT, errno) { 226 TH_LOG("Kernel does not support CONFIG_SECCOMP_FILTER!"); 227 } 228 } 229 230 TEST(mode_filter_without_nnp) 231 { 232 struct sock_filter filter[] = { 233 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 234 }; 235 struct sock_fprog prog = { 236 .len = (unsigned short)ARRAY_SIZE(filter), 237 .filter = filter, 238 }; 239 long ret; 240 241 ret = prctl(PR_GET_NO_NEW_PRIVS, 0, NULL, 0, 0); 242 ASSERT_LE(0, ret) { 243 TH_LOG("Expected 0 or unsupported for NO_NEW_PRIVS"); 244 } 245 errno = 0; 246 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 247 /* Succeeds with CAP_SYS_ADMIN, fails without */ 248 /* TODO(wad) check caps not euid */ 249 if (geteuid()) { 250 EXPECT_EQ(-1, ret); 251 EXPECT_EQ(EACCES, errno); 252 } else { 253 EXPECT_EQ(0, ret); 254 } 255 } 256 257 #define MAX_INSNS_PER_PATH 32768 258 259 TEST(filter_size_limits) 260 { 261 int i; 262 int count = BPF_MAXINSNS + 1; 263 struct sock_filter allow[] = { 264 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 265 }; 266 struct sock_filter *filter; 267 struct sock_fprog prog = { }; 268 long ret; 269 270 filter = calloc(count, sizeof(*filter)); 271 ASSERT_NE(NULL, filter); 272 273 for (i = 0; i < count; i++) 274 filter[i] = allow[0]; 275 276 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 277 ASSERT_EQ(0, ret); 278 279 prog.filter = filter; 280 prog.len = count; 281 282 /* Too many filter instructions in a single filter. */ 283 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 284 ASSERT_NE(0, ret) { 285 TH_LOG("Installing %d insn filter was allowed", prog.len); 286 } 287 288 /* One less is okay, though. */ 289 prog.len -= 1; 290 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 291 ASSERT_EQ(0, ret) { 292 TH_LOG("Installing %d insn filter wasn't allowed", prog.len); 293 } 294 } 295 296 TEST(filter_chain_limits) 297 { 298 int i; 299 int count = BPF_MAXINSNS; 300 struct sock_filter allow[] = { 301 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 302 }; 303 struct sock_filter *filter; 304 struct sock_fprog prog = { }; 305 long ret; 306 307 filter = calloc(count, sizeof(*filter)); 308 ASSERT_NE(NULL, filter); 309 310 for (i = 0; i < count; i++) 311 filter[i] = allow[0]; 312 313 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 314 ASSERT_EQ(0, ret); 315 316 prog.filter = filter; 317 prog.len = 1; 318 319 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 320 ASSERT_EQ(0, ret); 321 322 prog.len = count; 323 324 /* Too many total filter instructions. */ 325 for (i = 0; i < MAX_INSNS_PER_PATH; i++) { 326 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 327 if (ret != 0) 328 break; 329 } 330 ASSERT_NE(0, ret) { 331 TH_LOG("Allowed %d %d-insn filters (total with penalties:%d)", 332 i, count, i * (count + 4)); 333 } 334 } 335 336 TEST(mode_filter_cannot_move_to_strict) 337 { 338 struct sock_filter filter[] = { 339 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 340 }; 341 struct sock_fprog prog = { 342 .len = (unsigned short)ARRAY_SIZE(filter), 343 .filter = filter, 344 }; 345 long ret; 346 347 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 348 ASSERT_EQ(0, ret); 349 350 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 351 ASSERT_EQ(0, ret); 352 353 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT, NULL, 0, 0); 354 EXPECT_EQ(-1, ret); 355 EXPECT_EQ(EINVAL, errno); 356 } 357 358 359 TEST(mode_filter_get_seccomp) 360 { 361 struct sock_filter filter[] = { 362 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 363 }; 364 struct sock_fprog prog = { 365 .len = (unsigned short)ARRAY_SIZE(filter), 366 .filter = filter, 367 }; 368 long ret; 369 370 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 371 ASSERT_EQ(0, ret); 372 373 ret = prctl(PR_GET_SECCOMP, 0, 0, 0, 0); 374 EXPECT_EQ(0, ret); 375 376 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 377 ASSERT_EQ(0, ret); 378 379 ret = prctl(PR_GET_SECCOMP, 0, 0, 0, 0); 380 EXPECT_EQ(2, ret); 381 } 382 383 384 TEST(ALLOW_all) 385 { 386 struct sock_filter filter[] = { 387 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 388 }; 389 struct sock_fprog prog = { 390 .len = (unsigned short)ARRAY_SIZE(filter), 391 .filter = filter, 392 }; 393 long ret; 394 395 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 396 ASSERT_EQ(0, ret); 397 398 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 399 ASSERT_EQ(0, ret); 400 } 401 402 TEST(empty_prog) 403 { 404 struct sock_filter filter[] = { 405 }; 406 struct sock_fprog prog = { 407 .len = (unsigned short)ARRAY_SIZE(filter), 408 .filter = filter, 409 }; 410 long ret; 411 412 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 413 ASSERT_EQ(0, ret); 414 415 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 416 EXPECT_EQ(-1, ret); 417 EXPECT_EQ(EINVAL, errno); 418 } 419 420 TEST(log_all) 421 { 422 struct sock_filter filter[] = { 423 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_LOG), 424 }; 425 struct sock_fprog prog = { 426 .len = (unsigned short)ARRAY_SIZE(filter), 427 .filter = filter, 428 }; 429 long ret; 430 pid_t parent = getppid(); 431 432 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 433 ASSERT_EQ(0, ret); 434 435 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 436 ASSERT_EQ(0, ret); 437 438 /* getppid() should succeed and be logged (no check for logging) */ 439 EXPECT_EQ(parent, syscall(__NR_getppid)); 440 } 441 442 TEST_SIGNAL(unknown_ret_is_kill_inside, SIGSYS) 443 { 444 struct sock_filter filter[] = { 445 BPF_STMT(BPF_RET|BPF_K, 0x10000000U), 446 }; 447 struct sock_fprog prog = { 448 .len = (unsigned short)ARRAY_SIZE(filter), 449 .filter = filter, 450 }; 451 long ret; 452 453 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 454 ASSERT_EQ(0, ret); 455 456 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 457 ASSERT_EQ(0, ret); 458 EXPECT_EQ(0, syscall(__NR_getpid)) { 459 TH_LOG("getpid() shouldn't ever return"); 460 } 461 } 462 463 /* return code >= 0x80000000 is unused. */ 464 TEST_SIGNAL(unknown_ret_is_kill_above_allow, SIGSYS) 465 { 466 struct sock_filter filter[] = { 467 BPF_STMT(BPF_RET|BPF_K, 0x90000000U), 468 }; 469 struct sock_fprog prog = { 470 .len = (unsigned short)ARRAY_SIZE(filter), 471 .filter = filter, 472 }; 473 long ret; 474 475 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 476 ASSERT_EQ(0, ret); 477 478 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 479 ASSERT_EQ(0, ret); 480 EXPECT_EQ(0, syscall(__NR_getpid)) { 481 TH_LOG("getpid() shouldn't ever return"); 482 } 483 } 484 485 TEST_SIGNAL(KILL_all, SIGSYS) 486 { 487 struct sock_filter filter[] = { 488 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 489 }; 490 struct sock_fprog prog = { 491 .len = (unsigned short)ARRAY_SIZE(filter), 492 .filter = filter, 493 }; 494 long ret; 495 496 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 497 ASSERT_EQ(0, ret); 498 499 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 500 ASSERT_EQ(0, ret); 501 } 502 503 TEST_SIGNAL(KILL_one, SIGSYS) 504 { 505 struct sock_filter filter[] = { 506 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 507 offsetof(struct seccomp_data, nr)), 508 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 0, 1), 509 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 510 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 511 }; 512 struct sock_fprog prog = { 513 .len = (unsigned short)ARRAY_SIZE(filter), 514 .filter = filter, 515 }; 516 long ret; 517 pid_t parent = getppid(); 518 519 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 520 ASSERT_EQ(0, ret); 521 522 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 523 ASSERT_EQ(0, ret); 524 525 EXPECT_EQ(parent, syscall(__NR_getppid)); 526 /* getpid() should never return. */ 527 EXPECT_EQ(0, syscall(__NR_getpid)); 528 } 529 530 TEST_SIGNAL(KILL_one_arg_one, SIGSYS) 531 { 532 void *fatal_address; 533 struct sock_filter filter[] = { 534 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 535 offsetof(struct seccomp_data, nr)), 536 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_times, 1, 0), 537 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 538 /* Only both with lower 32-bit for now. */ 539 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, syscall_arg(0)), 540 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 541 (unsigned long)&fatal_address, 0, 1), 542 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 543 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 544 }; 545 struct sock_fprog prog = { 546 .len = (unsigned short)ARRAY_SIZE(filter), 547 .filter = filter, 548 }; 549 long ret; 550 pid_t parent = getppid(); 551 struct tms timebuf; 552 clock_t clock = times(&timebuf); 553 554 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 555 ASSERT_EQ(0, ret); 556 557 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 558 ASSERT_EQ(0, ret); 559 560 EXPECT_EQ(parent, syscall(__NR_getppid)); 561 EXPECT_LE(clock, syscall(__NR_times, &timebuf)); 562 /* times() should never return. */ 563 EXPECT_EQ(0, syscall(__NR_times, &fatal_address)); 564 } 565 566 TEST_SIGNAL(KILL_one_arg_six, SIGSYS) 567 { 568 #ifndef __NR_mmap2 569 int sysno = __NR_mmap; 570 #else 571 int sysno = __NR_mmap2; 572 #endif 573 struct sock_filter filter[] = { 574 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 575 offsetof(struct seccomp_data, nr)), 576 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, sysno, 1, 0), 577 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 578 /* Only both with lower 32-bit for now. */ 579 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, syscall_arg(5)), 580 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 0x0C0FFEE, 0, 1), 581 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 582 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 583 }; 584 struct sock_fprog prog = { 585 .len = (unsigned short)ARRAY_SIZE(filter), 586 .filter = filter, 587 }; 588 long ret; 589 pid_t parent = getppid(); 590 int fd; 591 void *map1, *map2; 592 int page_size = sysconf(_SC_PAGESIZE); 593 594 ASSERT_LT(0, page_size); 595 596 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 597 ASSERT_EQ(0, ret); 598 599 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 600 ASSERT_EQ(0, ret); 601 602 fd = open("/dev/zero", O_RDONLY); 603 ASSERT_NE(-1, fd); 604 605 EXPECT_EQ(parent, syscall(__NR_getppid)); 606 map1 = (void *)syscall(sysno, 607 NULL, page_size, PROT_READ, MAP_PRIVATE, fd, page_size); 608 EXPECT_NE(MAP_FAILED, map1); 609 /* mmap2() should never return. */ 610 map2 = (void *)syscall(sysno, 611 NULL, page_size, PROT_READ, MAP_PRIVATE, fd, 0x0C0FFEE); 612 EXPECT_EQ(MAP_FAILED, map2); 613 614 /* The test failed, so clean up the resources. */ 615 munmap(map1, page_size); 616 munmap(map2, page_size); 617 close(fd); 618 } 619 620 /* This is a thread task to die via seccomp filter violation. */ 621 void *kill_thread(void *data) 622 { 623 bool die = (bool)data; 624 625 if (die) { 626 prctl(PR_GET_SECCOMP, 0, 0, 0, 0); 627 return (void *)SIBLING_EXIT_FAILURE; 628 } 629 630 return (void *)SIBLING_EXIT_UNKILLED; 631 } 632 633 /* Prepare a thread that will kill itself or both of us. */ 634 void kill_thread_or_group(struct __test_metadata *_metadata, bool kill_process) 635 { 636 pthread_t thread; 637 void *status; 638 /* Kill only when calling __NR_prctl. */ 639 struct sock_filter filter_thread[] = { 640 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 641 offsetof(struct seccomp_data, nr)), 642 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_prctl, 0, 1), 643 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL_THREAD), 644 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 645 }; 646 struct sock_fprog prog_thread = { 647 .len = (unsigned short)ARRAY_SIZE(filter_thread), 648 .filter = filter_thread, 649 }; 650 struct sock_filter filter_process[] = { 651 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 652 offsetof(struct seccomp_data, nr)), 653 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_prctl, 0, 1), 654 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL_PROCESS), 655 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 656 }; 657 struct sock_fprog prog_process = { 658 .len = (unsigned short)ARRAY_SIZE(filter_process), 659 .filter = filter_process, 660 }; 661 662 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 663 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 664 } 665 666 ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0, 667 kill_process ? &prog_process : &prog_thread)); 668 669 /* 670 * Add the KILL_THREAD rule again to make sure that the KILL_PROCESS 671 * flag cannot be downgraded by a new filter. 672 */ 673 ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog_thread)); 674 675 /* Start a thread that will exit immediately. */ 676 ASSERT_EQ(0, pthread_create(&thread, NULL, kill_thread, (void *)false)); 677 ASSERT_EQ(0, pthread_join(thread, &status)); 678 ASSERT_EQ(SIBLING_EXIT_UNKILLED, (unsigned long)status); 679 680 /* Start a thread that will die immediately. */ 681 ASSERT_EQ(0, pthread_create(&thread, NULL, kill_thread, (void *)true)); 682 ASSERT_EQ(0, pthread_join(thread, &status)); 683 ASSERT_NE(SIBLING_EXIT_FAILURE, (unsigned long)status); 684 685 /* 686 * If we get here, only the spawned thread died. Let the parent know 687 * the whole process didn't die (i.e. this thread, the spawner, 688 * stayed running). 689 */ 690 exit(42); 691 } 692 693 TEST(KILL_thread) 694 { 695 int status; 696 pid_t child_pid; 697 698 child_pid = fork(); 699 ASSERT_LE(0, child_pid); 700 if (child_pid == 0) { 701 kill_thread_or_group(_metadata, false); 702 _exit(38); 703 } 704 705 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 706 707 /* If only the thread was killed, we'll see exit 42. */ 708 ASSERT_TRUE(WIFEXITED(status)); 709 ASSERT_EQ(42, WEXITSTATUS(status)); 710 } 711 712 TEST(KILL_process) 713 { 714 int status; 715 pid_t child_pid; 716 717 child_pid = fork(); 718 ASSERT_LE(0, child_pid); 719 if (child_pid == 0) { 720 kill_thread_or_group(_metadata, true); 721 _exit(38); 722 } 723 724 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 725 726 /* If the entire process was killed, we'll see SIGSYS. */ 727 ASSERT_TRUE(WIFSIGNALED(status)); 728 ASSERT_EQ(SIGSYS, WTERMSIG(status)); 729 } 730 731 /* TODO(wad) add 64-bit versus 32-bit arg tests. */ 732 TEST(arg_out_of_range) 733 { 734 struct sock_filter filter[] = { 735 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, syscall_arg(6)), 736 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 737 }; 738 struct sock_fprog prog = { 739 .len = (unsigned short)ARRAY_SIZE(filter), 740 .filter = filter, 741 }; 742 long ret; 743 744 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 745 ASSERT_EQ(0, ret); 746 747 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 748 EXPECT_EQ(-1, ret); 749 EXPECT_EQ(EINVAL, errno); 750 } 751 752 #define ERRNO_FILTER(name, errno) \ 753 struct sock_filter _read_filter_##name[] = { \ 754 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, \ 755 offsetof(struct seccomp_data, nr)), \ 756 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1), \ 757 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | errno), \ 758 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), \ 759 }; \ 760 struct sock_fprog prog_##name = { \ 761 .len = (unsigned short)ARRAY_SIZE(_read_filter_##name), \ 762 .filter = _read_filter_##name, \ 763 } 764 765 /* Make sure basic errno values are correctly passed through a filter. */ 766 TEST(ERRNO_valid) 767 { 768 ERRNO_FILTER(valid, E2BIG); 769 long ret; 770 pid_t parent = getppid(); 771 772 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 773 ASSERT_EQ(0, ret); 774 775 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog_valid); 776 ASSERT_EQ(0, ret); 777 778 EXPECT_EQ(parent, syscall(__NR_getppid)); 779 EXPECT_EQ(-1, read(0, NULL, 0)); 780 EXPECT_EQ(E2BIG, errno); 781 } 782 783 /* Make sure an errno of zero is correctly handled by the arch code. */ 784 TEST(ERRNO_zero) 785 { 786 ERRNO_FILTER(zero, 0); 787 long ret; 788 pid_t parent = getppid(); 789 790 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 791 ASSERT_EQ(0, ret); 792 793 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog_zero); 794 ASSERT_EQ(0, ret); 795 796 EXPECT_EQ(parent, syscall(__NR_getppid)); 797 /* "errno" of 0 is ok. */ 798 EXPECT_EQ(0, read(0, NULL, 0)); 799 } 800 801 /* 802 * The SECCOMP_RET_DATA mask is 16 bits wide, but errno is smaller. 803 * This tests that the errno value gets capped correctly, fixed by 804 * 580c57f10768 ("seccomp: cap SECCOMP_RET_ERRNO data to MAX_ERRNO"). 805 */ 806 TEST(ERRNO_capped) 807 { 808 ERRNO_FILTER(capped, 4096); 809 long ret; 810 pid_t parent = getppid(); 811 812 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 813 ASSERT_EQ(0, ret); 814 815 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog_capped); 816 ASSERT_EQ(0, ret); 817 818 EXPECT_EQ(parent, syscall(__NR_getppid)); 819 EXPECT_EQ(-1, read(0, NULL, 0)); 820 EXPECT_EQ(4095, errno); 821 } 822 823 /* 824 * Filters are processed in reverse order: last applied is executed first. 825 * Since only the SECCOMP_RET_ACTION mask is tested for return values, the 826 * SECCOMP_RET_DATA mask results will follow the most recently applied 827 * matching filter return (and not the lowest or highest value). 828 */ 829 TEST(ERRNO_order) 830 { 831 ERRNO_FILTER(first, 11); 832 ERRNO_FILTER(second, 13); 833 ERRNO_FILTER(third, 12); 834 long ret; 835 pid_t parent = getppid(); 836 837 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 838 ASSERT_EQ(0, ret); 839 840 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog_first); 841 ASSERT_EQ(0, ret); 842 843 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog_second); 844 ASSERT_EQ(0, ret); 845 846 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog_third); 847 ASSERT_EQ(0, ret); 848 849 EXPECT_EQ(parent, syscall(__NR_getppid)); 850 EXPECT_EQ(-1, read(0, NULL, 0)); 851 EXPECT_EQ(12, errno); 852 } 853 854 FIXTURE_DATA(TRAP) { 855 struct sock_fprog prog; 856 }; 857 858 FIXTURE_SETUP(TRAP) 859 { 860 struct sock_filter filter[] = { 861 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 862 offsetof(struct seccomp_data, nr)), 863 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 0, 1), 864 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRAP), 865 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 866 }; 867 868 memset(&self->prog, 0, sizeof(self->prog)); 869 self->prog.filter = malloc(sizeof(filter)); 870 ASSERT_NE(NULL, self->prog.filter); 871 memcpy(self->prog.filter, filter, sizeof(filter)); 872 self->prog.len = (unsigned short)ARRAY_SIZE(filter); 873 } 874 875 FIXTURE_TEARDOWN(TRAP) 876 { 877 if (self->prog.filter) 878 free(self->prog.filter); 879 } 880 881 TEST_F_SIGNAL(TRAP, dfl, SIGSYS) 882 { 883 long ret; 884 885 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 886 ASSERT_EQ(0, ret); 887 888 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog); 889 ASSERT_EQ(0, ret); 890 syscall(__NR_getpid); 891 } 892 893 /* Ensure that SIGSYS overrides SIG_IGN */ 894 TEST_F_SIGNAL(TRAP, ign, SIGSYS) 895 { 896 long ret; 897 898 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 899 ASSERT_EQ(0, ret); 900 901 signal(SIGSYS, SIG_IGN); 902 903 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog); 904 ASSERT_EQ(0, ret); 905 syscall(__NR_getpid); 906 } 907 908 static siginfo_t TRAP_info; 909 static volatile int TRAP_nr; 910 static void TRAP_action(int nr, siginfo_t *info, void *void_context) 911 { 912 memcpy(&TRAP_info, info, sizeof(TRAP_info)); 913 TRAP_nr = nr; 914 } 915 916 TEST_F(TRAP, handler) 917 { 918 int ret, test; 919 struct sigaction act; 920 sigset_t mask; 921 922 memset(&act, 0, sizeof(act)); 923 sigemptyset(&mask); 924 sigaddset(&mask, SIGSYS); 925 926 act.sa_sigaction = &TRAP_action; 927 act.sa_flags = SA_SIGINFO; 928 ret = sigaction(SIGSYS, &act, NULL); 929 ASSERT_EQ(0, ret) { 930 TH_LOG("sigaction failed"); 931 } 932 ret = sigprocmask(SIG_UNBLOCK, &mask, NULL); 933 ASSERT_EQ(0, ret) { 934 TH_LOG("sigprocmask failed"); 935 } 936 937 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 938 ASSERT_EQ(0, ret); 939 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog); 940 ASSERT_EQ(0, ret); 941 TRAP_nr = 0; 942 memset(&TRAP_info, 0, sizeof(TRAP_info)); 943 /* Expect the registers to be rolled back. (nr = error) may vary 944 * based on arch. */ 945 ret = syscall(__NR_getpid); 946 /* Silence gcc warning about volatile. */ 947 test = TRAP_nr; 948 EXPECT_EQ(SIGSYS, test); 949 struct local_sigsys { 950 void *_call_addr; /* calling user insn */ 951 int _syscall; /* triggering system call number */ 952 unsigned int _arch; /* AUDIT_ARCH_* of syscall */ 953 } *sigsys = (struct local_sigsys *) 954 #ifdef si_syscall 955 &(TRAP_info.si_call_addr); 956 #else 957 &TRAP_info.si_pid; 958 #endif 959 EXPECT_EQ(__NR_getpid, sigsys->_syscall); 960 /* Make sure arch is non-zero. */ 961 EXPECT_NE(0, sigsys->_arch); 962 EXPECT_NE(0, (unsigned long)sigsys->_call_addr); 963 } 964 965 FIXTURE_DATA(precedence) { 966 struct sock_fprog allow; 967 struct sock_fprog log; 968 struct sock_fprog trace; 969 struct sock_fprog error; 970 struct sock_fprog trap; 971 struct sock_fprog kill; 972 }; 973 974 FIXTURE_SETUP(precedence) 975 { 976 struct sock_filter allow_insns[] = { 977 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 978 }; 979 struct sock_filter log_insns[] = { 980 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 981 offsetof(struct seccomp_data, nr)), 982 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0), 983 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 984 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_LOG), 985 }; 986 struct sock_filter trace_insns[] = { 987 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 988 offsetof(struct seccomp_data, nr)), 989 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0), 990 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 991 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE), 992 }; 993 struct sock_filter error_insns[] = { 994 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 995 offsetof(struct seccomp_data, nr)), 996 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0), 997 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 998 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO), 999 }; 1000 struct sock_filter trap_insns[] = { 1001 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 1002 offsetof(struct seccomp_data, nr)), 1003 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0), 1004 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1005 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRAP), 1006 }; 1007 struct sock_filter kill_insns[] = { 1008 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 1009 offsetof(struct seccomp_data, nr)), 1010 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0), 1011 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1012 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 1013 }; 1014 1015 memset(self, 0, sizeof(*self)); 1016 #define FILTER_ALLOC(_x) \ 1017 self->_x.filter = malloc(sizeof(_x##_insns)); \ 1018 ASSERT_NE(NULL, self->_x.filter); \ 1019 memcpy(self->_x.filter, &_x##_insns, sizeof(_x##_insns)); \ 1020 self->_x.len = (unsigned short)ARRAY_SIZE(_x##_insns) 1021 FILTER_ALLOC(allow); 1022 FILTER_ALLOC(log); 1023 FILTER_ALLOC(trace); 1024 FILTER_ALLOC(error); 1025 FILTER_ALLOC(trap); 1026 FILTER_ALLOC(kill); 1027 } 1028 1029 FIXTURE_TEARDOWN(precedence) 1030 { 1031 #define FILTER_FREE(_x) if (self->_x.filter) free(self->_x.filter) 1032 FILTER_FREE(allow); 1033 FILTER_FREE(log); 1034 FILTER_FREE(trace); 1035 FILTER_FREE(error); 1036 FILTER_FREE(trap); 1037 FILTER_FREE(kill); 1038 } 1039 1040 TEST_F(precedence, allow_ok) 1041 { 1042 pid_t parent, res = 0; 1043 long ret; 1044 1045 parent = getppid(); 1046 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1047 ASSERT_EQ(0, ret); 1048 1049 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 1050 ASSERT_EQ(0, ret); 1051 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log); 1052 ASSERT_EQ(0, ret); 1053 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 1054 ASSERT_EQ(0, ret); 1055 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error); 1056 ASSERT_EQ(0, ret); 1057 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap); 1058 ASSERT_EQ(0, ret); 1059 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->kill); 1060 ASSERT_EQ(0, ret); 1061 /* Should work just fine. */ 1062 res = syscall(__NR_getppid); 1063 EXPECT_EQ(parent, res); 1064 } 1065 1066 TEST_F_SIGNAL(precedence, kill_is_highest, SIGSYS) 1067 { 1068 pid_t parent, res = 0; 1069 long ret; 1070 1071 parent = getppid(); 1072 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1073 ASSERT_EQ(0, ret); 1074 1075 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 1076 ASSERT_EQ(0, ret); 1077 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log); 1078 ASSERT_EQ(0, ret); 1079 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 1080 ASSERT_EQ(0, ret); 1081 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error); 1082 ASSERT_EQ(0, ret); 1083 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap); 1084 ASSERT_EQ(0, ret); 1085 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->kill); 1086 ASSERT_EQ(0, ret); 1087 /* Should work just fine. */ 1088 res = syscall(__NR_getppid); 1089 EXPECT_EQ(parent, res); 1090 /* getpid() should never return. */ 1091 res = syscall(__NR_getpid); 1092 EXPECT_EQ(0, res); 1093 } 1094 1095 TEST_F_SIGNAL(precedence, kill_is_highest_in_any_order, SIGSYS) 1096 { 1097 pid_t parent; 1098 long ret; 1099 1100 parent = getppid(); 1101 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1102 ASSERT_EQ(0, ret); 1103 1104 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 1105 ASSERT_EQ(0, ret); 1106 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->kill); 1107 ASSERT_EQ(0, ret); 1108 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error); 1109 ASSERT_EQ(0, ret); 1110 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log); 1111 ASSERT_EQ(0, ret); 1112 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 1113 ASSERT_EQ(0, ret); 1114 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap); 1115 ASSERT_EQ(0, ret); 1116 /* Should work just fine. */ 1117 EXPECT_EQ(parent, syscall(__NR_getppid)); 1118 /* getpid() should never return. */ 1119 EXPECT_EQ(0, syscall(__NR_getpid)); 1120 } 1121 1122 TEST_F_SIGNAL(precedence, trap_is_second, SIGSYS) 1123 { 1124 pid_t parent; 1125 long ret; 1126 1127 parent = getppid(); 1128 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1129 ASSERT_EQ(0, ret); 1130 1131 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 1132 ASSERT_EQ(0, ret); 1133 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log); 1134 ASSERT_EQ(0, ret); 1135 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 1136 ASSERT_EQ(0, ret); 1137 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error); 1138 ASSERT_EQ(0, ret); 1139 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap); 1140 ASSERT_EQ(0, ret); 1141 /* Should work just fine. */ 1142 EXPECT_EQ(parent, syscall(__NR_getppid)); 1143 /* getpid() should never return. */ 1144 EXPECT_EQ(0, syscall(__NR_getpid)); 1145 } 1146 1147 TEST_F_SIGNAL(precedence, trap_is_second_in_any_order, SIGSYS) 1148 { 1149 pid_t parent; 1150 long ret; 1151 1152 parent = getppid(); 1153 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1154 ASSERT_EQ(0, ret); 1155 1156 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 1157 ASSERT_EQ(0, ret); 1158 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap); 1159 ASSERT_EQ(0, ret); 1160 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log); 1161 ASSERT_EQ(0, ret); 1162 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 1163 ASSERT_EQ(0, ret); 1164 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error); 1165 ASSERT_EQ(0, ret); 1166 /* Should work just fine. */ 1167 EXPECT_EQ(parent, syscall(__NR_getppid)); 1168 /* getpid() should never return. */ 1169 EXPECT_EQ(0, syscall(__NR_getpid)); 1170 } 1171 1172 TEST_F(precedence, errno_is_third) 1173 { 1174 pid_t parent; 1175 long ret; 1176 1177 parent = getppid(); 1178 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1179 ASSERT_EQ(0, ret); 1180 1181 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 1182 ASSERT_EQ(0, ret); 1183 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log); 1184 ASSERT_EQ(0, ret); 1185 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 1186 ASSERT_EQ(0, ret); 1187 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error); 1188 ASSERT_EQ(0, ret); 1189 /* Should work just fine. */ 1190 EXPECT_EQ(parent, syscall(__NR_getppid)); 1191 EXPECT_EQ(0, syscall(__NR_getpid)); 1192 } 1193 1194 TEST_F(precedence, errno_is_third_in_any_order) 1195 { 1196 pid_t parent; 1197 long ret; 1198 1199 parent = getppid(); 1200 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1201 ASSERT_EQ(0, ret); 1202 1203 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log); 1204 ASSERT_EQ(0, ret); 1205 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error); 1206 ASSERT_EQ(0, ret); 1207 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 1208 ASSERT_EQ(0, ret); 1209 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 1210 ASSERT_EQ(0, ret); 1211 /* Should work just fine. */ 1212 EXPECT_EQ(parent, syscall(__NR_getppid)); 1213 EXPECT_EQ(0, syscall(__NR_getpid)); 1214 } 1215 1216 TEST_F(precedence, trace_is_fourth) 1217 { 1218 pid_t parent; 1219 long ret; 1220 1221 parent = getppid(); 1222 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1223 ASSERT_EQ(0, ret); 1224 1225 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 1226 ASSERT_EQ(0, ret); 1227 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log); 1228 ASSERT_EQ(0, ret); 1229 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 1230 ASSERT_EQ(0, ret); 1231 /* Should work just fine. */ 1232 EXPECT_EQ(parent, syscall(__NR_getppid)); 1233 /* No ptracer */ 1234 EXPECT_EQ(-1, syscall(__NR_getpid)); 1235 } 1236 1237 TEST_F(precedence, trace_is_fourth_in_any_order) 1238 { 1239 pid_t parent; 1240 long ret; 1241 1242 parent = getppid(); 1243 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1244 ASSERT_EQ(0, ret); 1245 1246 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 1247 ASSERT_EQ(0, ret); 1248 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 1249 ASSERT_EQ(0, ret); 1250 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log); 1251 ASSERT_EQ(0, ret); 1252 /* Should work just fine. */ 1253 EXPECT_EQ(parent, syscall(__NR_getppid)); 1254 /* No ptracer */ 1255 EXPECT_EQ(-1, syscall(__NR_getpid)); 1256 } 1257 1258 TEST_F(precedence, log_is_fifth) 1259 { 1260 pid_t mypid, parent; 1261 long ret; 1262 1263 mypid = getpid(); 1264 parent = getppid(); 1265 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1266 ASSERT_EQ(0, ret); 1267 1268 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 1269 ASSERT_EQ(0, ret); 1270 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log); 1271 ASSERT_EQ(0, ret); 1272 /* Should work just fine. */ 1273 EXPECT_EQ(parent, syscall(__NR_getppid)); 1274 /* Should also work just fine */ 1275 EXPECT_EQ(mypid, syscall(__NR_getpid)); 1276 } 1277 1278 TEST_F(precedence, log_is_fifth_in_any_order) 1279 { 1280 pid_t mypid, parent; 1281 long ret; 1282 1283 mypid = getpid(); 1284 parent = getppid(); 1285 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1286 ASSERT_EQ(0, ret); 1287 1288 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log); 1289 ASSERT_EQ(0, ret); 1290 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 1291 ASSERT_EQ(0, ret); 1292 /* Should work just fine. */ 1293 EXPECT_EQ(parent, syscall(__NR_getppid)); 1294 /* Should also work just fine */ 1295 EXPECT_EQ(mypid, syscall(__NR_getpid)); 1296 } 1297 1298 #ifndef PTRACE_O_TRACESECCOMP 1299 #define PTRACE_O_TRACESECCOMP 0x00000080 1300 #endif 1301 1302 /* Catch the Ubuntu 12.04 value error. */ 1303 #if PTRACE_EVENT_SECCOMP != 7 1304 #undef PTRACE_EVENT_SECCOMP 1305 #endif 1306 1307 #ifndef PTRACE_EVENT_SECCOMP 1308 #define PTRACE_EVENT_SECCOMP 7 1309 #endif 1310 1311 #define IS_SECCOMP_EVENT(status) ((status >> 16) == PTRACE_EVENT_SECCOMP) 1312 bool tracer_running; 1313 void tracer_stop(int sig) 1314 { 1315 tracer_running = false; 1316 } 1317 1318 typedef void tracer_func_t(struct __test_metadata *_metadata, 1319 pid_t tracee, int status, void *args); 1320 1321 void start_tracer(struct __test_metadata *_metadata, int fd, pid_t tracee, 1322 tracer_func_t tracer_func, void *args, bool ptrace_syscall) 1323 { 1324 int ret = -1; 1325 struct sigaction action = { 1326 .sa_handler = tracer_stop, 1327 }; 1328 1329 /* Allow external shutdown. */ 1330 tracer_running = true; 1331 ASSERT_EQ(0, sigaction(SIGUSR1, &action, NULL)); 1332 1333 errno = 0; 1334 while (ret == -1 && errno != EINVAL) 1335 ret = ptrace(PTRACE_ATTACH, tracee, NULL, 0); 1336 ASSERT_EQ(0, ret) { 1337 kill(tracee, SIGKILL); 1338 } 1339 /* Wait for attach stop */ 1340 wait(NULL); 1341 1342 ret = ptrace(PTRACE_SETOPTIONS, tracee, NULL, ptrace_syscall ? 1343 PTRACE_O_TRACESYSGOOD : 1344 PTRACE_O_TRACESECCOMP); 1345 ASSERT_EQ(0, ret) { 1346 TH_LOG("Failed to set PTRACE_O_TRACESECCOMP"); 1347 kill(tracee, SIGKILL); 1348 } 1349 ret = ptrace(ptrace_syscall ? PTRACE_SYSCALL : PTRACE_CONT, 1350 tracee, NULL, 0); 1351 ASSERT_EQ(0, ret); 1352 1353 /* Unblock the tracee */ 1354 ASSERT_EQ(1, write(fd, "A", 1)); 1355 ASSERT_EQ(0, close(fd)); 1356 1357 /* Run until we're shut down. Must assert to stop execution. */ 1358 while (tracer_running) { 1359 int status; 1360 1361 if (wait(&status) != tracee) 1362 continue; 1363 if (WIFSIGNALED(status) || WIFEXITED(status)) 1364 /* Child is dead. Time to go. */ 1365 return; 1366 1367 /* Check if this is a seccomp event. */ 1368 ASSERT_EQ(!ptrace_syscall, IS_SECCOMP_EVENT(status)); 1369 1370 tracer_func(_metadata, tracee, status, args); 1371 1372 ret = ptrace(ptrace_syscall ? PTRACE_SYSCALL : PTRACE_CONT, 1373 tracee, NULL, 0); 1374 ASSERT_EQ(0, ret); 1375 } 1376 /* Directly report the status of our test harness results. */ 1377 syscall(__NR_exit, _metadata->passed ? EXIT_SUCCESS : EXIT_FAILURE); 1378 } 1379 1380 /* Common tracer setup/teardown functions. */ 1381 void cont_handler(int num) 1382 { } 1383 pid_t setup_trace_fixture(struct __test_metadata *_metadata, 1384 tracer_func_t func, void *args, bool ptrace_syscall) 1385 { 1386 char sync; 1387 int pipefd[2]; 1388 pid_t tracer_pid; 1389 pid_t tracee = getpid(); 1390 1391 /* Setup a pipe for clean synchronization. */ 1392 ASSERT_EQ(0, pipe(pipefd)); 1393 1394 /* Fork a child which we'll promote to tracer */ 1395 tracer_pid = fork(); 1396 ASSERT_LE(0, tracer_pid); 1397 signal(SIGALRM, cont_handler); 1398 if (tracer_pid == 0) { 1399 close(pipefd[0]); 1400 start_tracer(_metadata, pipefd[1], tracee, func, args, 1401 ptrace_syscall); 1402 syscall(__NR_exit, 0); 1403 } 1404 close(pipefd[1]); 1405 prctl(PR_SET_PTRACER, tracer_pid, 0, 0, 0); 1406 read(pipefd[0], &sync, 1); 1407 close(pipefd[0]); 1408 1409 return tracer_pid; 1410 } 1411 void teardown_trace_fixture(struct __test_metadata *_metadata, 1412 pid_t tracer) 1413 { 1414 if (tracer) { 1415 int status; 1416 /* 1417 * Extract the exit code from the other process and 1418 * adopt it for ourselves in case its asserts failed. 1419 */ 1420 ASSERT_EQ(0, kill(tracer, SIGUSR1)); 1421 ASSERT_EQ(tracer, waitpid(tracer, &status, 0)); 1422 if (WEXITSTATUS(status)) 1423 _metadata->passed = 0; 1424 } 1425 } 1426 1427 /* "poke" tracer arguments and function. */ 1428 struct tracer_args_poke_t { 1429 unsigned long poke_addr; 1430 }; 1431 1432 void tracer_poke(struct __test_metadata *_metadata, pid_t tracee, int status, 1433 void *args) 1434 { 1435 int ret; 1436 unsigned long msg; 1437 struct tracer_args_poke_t *info = (struct tracer_args_poke_t *)args; 1438 1439 ret = ptrace(PTRACE_GETEVENTMSG, tracee, NULL, &msg); 1440 EXPECT_EQ(0, ret); 1441 /* If this fails, don't try to recover. */ 1442 ASSERT_EQ(0x1001, msg) { 1443 kill(tracee, SIGKILL); 1444 } 1445 /* 1446 * Poke in the message. 1447 * Registers are not touched to try to keep this relatively arch 1448 * agnostic. 1449 */ 1450 ret = ptrace(PTRACE_POKEDATA, tracee, info->poke_addr, 0x1001); 1451 EXPECT_EQ(0, ret); 1452 } 1453 1454 FIXTURE_DATA(TRACE_poke) { 1455 struct sock_fprog prog; 1456 pid_t tracer; 1457 long poked; 1458 struct tracer_args_poke_t tracer_args; 1459 }; 1460 1461 FIXTURE_SETUP(TRACE_poke) 1462 { 1463 struct sock_filter filter[] = { 1464 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 1465 offsetof(struct seccomp_data, nr)), 1466 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1), 1467 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1001), 1468 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1469 }; 1470 1471 self->poked = 0; 1472 memset(&self->prog, 0, sizeof(self->prog)); 1473 self->prog.filter = malloc(sizeof(filter)); 1474 ASSERT_NE(NULL, self->prog.filter); 1475 memcpy(self->prog.filter, filter, sizeof(filter)); 1476 self->prog.len = (unsigned short)ARRAY_SIZE(filter); 1477 1478 /* Set up tracer args. */ 1479 self->tracer_args.poke_addr = (unsigned long)&self->poked; 1480 1481 /* Launch tracer. */ 1482 self->tracer = setup_trace_fixture(_metadata, tracer_poke, 1483 &self->tracer_args, false); 1484 } 1485 1486 FIXTURE_TEARDOWN(TRACE_poke) 1487 { 1488 teardown_trace_fixture(_metadata, self->tracer); 1489 if (self->prog.filter) 1490 free(self->prog.filter); 1491 } 1492 1493 TEST_F(TRACE_poke, read_has_side_effects) 1494 { 1495 ssize_t ret; 1496 1497 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1498 ASSERT_EQ(0, ret); 1499 1500 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); 1501 ASSERT_EQ(0, ret); 1502 1503 EXPECT_EQ(0, self->poked); 1504 ret = read(-1, NULL, 0); 1505 EXPECT_EQ(-1, ret); 1506 EXPECT_EQ(0x1001, self->poked); 1507 } 1508 1509 TEST_F(TRACE_poke, getpid_runs_normally) 1510 { 1511 long ret; 1512 1513 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1514 ASSERT_EQ(0, ret); 1515 1516 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); 1517 ASSERT_EQ(0, ret); 1518 1519 EXPECT_EQ(0, self->poked); 1520 EXPECT_NE(0, syscall(__NR_getpid)); 1521 EXPECT_EQ(0, self->poked); 1522 } 1523 1524 #if defined(__x86_64__) 1525 # define ARCH_REGS struct user_regs_struct 1526 # define SYSCALL_NUM orig_rax 1527 # define SYSCALL_RET rax 1528 #elif defined(__i386__) 1529 # define ARCH_REGS struct user_regs_struct 1530 # define SYSCALL_NUM orig_eax 1531 # define SYSCALL_RET eax 1532 #elif defined(__arm__) 1533 # define ARCH_REGS struct pt_regs 1534 # define SYSCALL_NUM ARM_r7 1535 # define SYSCALL_RET ARM_r0 1536 #elif defined(__aarch64__) 1537 # define ARCH_REGS struct user_pt_regs 1538 # define SYSCALL_NUM regs[8] 1539 # define SYSCALL_RET regs[0] 1540 #elif defined(__hppa__) 1541 # define ARCH_REGS struct user_regs_struct 1542 # define SYSCALL_NUM gr[20] 1543 # define SYSCALL_RET gr[28] 1544 #elif defined(__powerpc__) 1545 # define ARCH_REGS struct pt_regs 1546 # define SYSCALL_NUM gpr[0] 1547 # define SYSCALL_RET gpr[3] 1548 #elif defined(__s390__) 1549 # define ARCH_REGS s390_regs 1550 # define SYSCALL_NUM gprs[2] 1551 # define SYSCALL_RET gprs[2] 1552 #elif defined(__mips__) 1553 # define ARCH_REGS struct pt_regs 1554 # define SYSCALL_NUM regs[2] 1555 # define SYSCALL_SYSCALL_NUM regs[4] 1556 # define SYSCALL_RET regs[2] 1557 # define SYSCALL_NUM_RET_SHARE_REG 1558 #else 1559 # error "Do not know how to find your architecture's registers and syscalls" 1560 #endif 1561 1562 /* When the syscall return can't be changed, stub out the tests for it. */ 1563 #ifdef SYSCALL_NUM_RET_SHARE_REG 1564 # define EXPECT_SYSCALL_RETURN(val, action) EXPECT_EQ(-1, action) 1565 #else 1566 # define EXPECT_SYSCALL_RETURN(val, action) EXPECT_EQ(val, action) 1567 #endif 1568 1569 /* Use PTRACE_GETREGS and PTRACE_SETREGS when available. This is useful for 1570 * architectures without HAVE_ARCH_TRACEHOOK (e.g. User-mode Linux). 1571 */ 1572 #if defined(__x86_64__) || defined(__i386__) || defined(__mips__) 1573 #define HAVE_GETREGS 1574 #endif 1575 1576 /* Architecture-specific syscall fetching routine. */ 1577 int get_syscall(struct __test_metadata *_metadata, pid_t tracee) 1578 { 1579 ARCH_REGS regs; 1580 #ifdef HAVE_GETREGS 1581 EXPECT_EQ(0, ptrace(PTRACE_GETREGS, tracee, 0, ®s)) { 1582 TH_LOG("PTRACE_GETREGS failed"); 1583 return -1; 1584 } 1585 #else 1586 struct iovec iov; 1587 1588 iov.iov_base = ®s; 1589 iov.iov_len = sizeof(regs); 1590 EXPECT_EQ(0, ptrace(PTRACE_GETREGSET, tracee, NT_PRSTATUS, &iov)) { 1591 TH_LOG("PTRACE_GETREGSET failed"); 1592 return -1; 1593 } 1594 #endif 1595 1596 #if defined(__mips__) 1597 if (regs.SYSCALL_NUM == __NR_O32_Linux) 1598 return regs.SYSCALL_SYSCALL_NUM; 1599 #endif 1600 return regs.SYSCALL_NUM; 1601 } 1602 1603 /* Architecture-specific syscall changing routine. */ 1604 void change_syscall(struct __test_metadata *_metadata, 1605 pid_t tracee, int syscall) 1606 { 1607 int ret; 1608 ARCH_REGS regs; 1609 #ifdef HAVE_GETREGS 1610 ret = ptrace(PTRACE_GETREGS, tracee, 0, ®s); 1611 #else 1612 struct iovec iov; 1613 iov.iov_base = ®s; 1614 iov.iov_len = sizeof(regs); 1615 ret = ptrace(PTRACE_GETREGSET, tracee, NT_PRSTATUS, &iov); 1616 #endif 1617 EXPECT_EQ(0, ret) {} 1618 1619 #if defined(__x86_64__) || defined(__i386__) || defined(__powerpc__) || \ 1620 defined(__s390__) || defined(__hppa__) 1621 { 1622 regs.SYSCALL_NUM = syscall; 1623 } 1624 #elif defined(__mips__) 1625 { 1626 if (regs.SYSCALL_NUM == __NR_O32_Linux) 1627 regs.SYSCALL_SYSCALL_NUM = syscall; 1628 else 1629 regs.SYSCALL_NUM = syscall; 1630 } 1631 1632 #elif defined(__arm__) 1633 # ifndef PTRACE_SET_SYSCALL 1634 # define PTRACE_SET_SYSCALL 23 1635 # endif 1636 { 1637 ret = ptrace(PTRACE_SET_SYSCALL, tracee, NULL, syscall); 1638 EXPECT_EQ(0, ret); 1639 } 1640 1641 #elif defined(__aarch64__) 1642 # ifndef NT_ARM_SYSTEM_CALL 1643 # define NT_ARM_SYSTEM_CALL 0x404 1644 # endif 1645 { 1646 iov.iov_base = &syscall; 1647 iov.iov_len = sizeof(syscall); 1648 ret = ptrace(PTRACE_SETREGSET, tracee, NT_ARM_SYSTEM_CALL, 1649 &iov); 1650 EXPECT_EQ(0, ret); 1651 } 1652 1653 #else 1654 ASSERT_EQ(1, 0) { 1655 TH_LOG("How is the syscall changed on this architecture?"); 1656 } 1657 #endif 1658 1659 /* If syscall is skipped, change return value. */ 1660 if (syscall == -1) 1661 #ifdef SYSCALL_NUM_RET_SHARE_REG 1662 TH_LOG("Can't modify syscall return on this architecture"); 1663 #else 1664 regs.SYSCALL_RET = EPERM; 1665 #endif 1666 1667 #ifdef HAVE_GETREGS 1668 ret = ptrace(PTRACE_SETREGS, tracee, 0, ®s); 1669 #else 1670 iov.iov_base = ®s; 1671 iov.iov_len = sizeof(regs); 1672 ret = ptrace(PTRACE_SETREGSET, tracee, NT_PRSTATUS, &iov); 1673 #endif 1674 EXPECT_EQ(0, ret); 1675 } 1676 1677 void tracer_syscall(struct __test_metadata *_metadata, pid_t tracee, 1678 int status, void *args) 1679 { 1680 int ret; 1681 unsigned long msg; 1682 1683 /* Make sure we got the right message. */ 1684 ret = ptrace(PTRACE_GETEVENTMSG, tracee, NULL, &msg); 1685 EXPECT_EQ(0, ret); 1686 1687 /* Validate and take action on expected syscalls. */ 1688 switch (msg) { 1689 case 0x1002: 1690 /* change getpid to getppid. */ 1691 EXPECT_EQ(__NR_getpid, get_syscall(_metadata, tracee)); 1692 change_syscall(_metadata, tracee, __NR_getppid); 1693 break; 1694 case 0x1003: 1695 /* skip gettid. */ 1696 EXPECT_EQ(__NR_gettid, get_syscall(_metadata, tracee)); 1697 change_syscall(_metadata, tracee, -1); 1698 break; 1699 case 0x1004: 1700 /* do nothing (allow getppid) */ 1701 EXPECT_EQ(__NR_getppid, get_syscall(_metadata, tracee)); 1702 break; 1703 default: 1704 EXPECT_EQ(0, msg) { 1705 TH_LOG("Unknown PTRACE_GETEVENTMSG: 0x%lx", msg); 1706 kill(tracee, SIGKILL); 1707 } 1708 } 1709 1710 } 1711 1712 void tracer_ptrace(struct __test_metadata *_metadata, pid_t tracee, 1713 int status, void *args) 1714 { 1715 int ret, nr; 1716 unsigned long msg; 1717 static bool entry; 1718 1719 /* Make sure we got an empty message. */ 1720 ret = ptrace(PTRACE_GETEVENTMSG, tracee, NULL, &msg); 1721 EXPECT_EQ(0, ret); 1722 EXPECT_EQ(0, msg); 1723 1724 /* The only way to tell PTRACE_SYSCALL entry/exit is by counting. */ 1725 entry = !entry; 1726 if (!entry) 1727 return; 1728 1729 nr = get_syscall(_metadata, tracee); 1730 1731 if (nr == __NR_getpid) 1732 change_syscall(_metadata, tracee, __NR_getppid); 1733 if (nr == __NR_openat) 1734 change_syscall(_metadata, tracee, -1); 1735 } 1736 1737 FIXTURE_DATA(TRACE_syscall) { 1738 struct sock_fprog prog; 1739 pid_t tracer, mytid, mypid, parent; 1740 }; 1741 1742 FIXTURE_SETUP(TRACE_syscall) 1743 { 1744 struct sock_filter filter[] = { 1745 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 1746 offsetof(struct seccomp_data, nr)), 1747 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 0, 1), 1748 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1002), 1749 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_gettid, 0, 1), 1750 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1003), 1751 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1), 1752 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1004), 1753 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1754 }; 1755 1756 memset(&self->prog, 0, sizeof(self->prog)); 1757 self->prog.filter = malloc(sizeof(filter)); 1758 ASSERT_NE(NULL, self->prog.filter); 1759 memcpy(self->prog.filter, filter, sizeof(filter)); 1760 self->prog.len = (unsigned short)ARRAY_SIZE(filter); 1761 1762 /* Prepare some testable syscall results. */ 1763 self->mytid = syscall(__NR_gettid); 1764 ASSERT_GT(self->mytid, 0); 1765 ASSERT_NE(self->mytid, 1) { 1766 TH_LOG("Running this test as init is not supported. :)"); 1767 } 1768 1769 self->mypid = getpid(); 1770 ASSERT_GT(self->mypid, 0); 1771 ASSERT_EQ(self->mytid, self->mypid); 1772 1773 self->parent = getppid(); 1774 ASSERT_GT(self->parent, 0); 1775 ASSERT_NE(self->parent, self->mypid); 1776 1777 /* Launch tracer. */ 1778 self->tracer = setup_trace_fixture(_metadata, tracer_syscall, NULL, 1779 false); 1780 } 1781 1782 FIXTURE_TEARDOWN(TRACE_syscall) 1783 { 1784 teardown_trace_fixture(_metadata, self->tracer); 1785 if (self->prog.filter) 1786 free(self->prog.filter); 1787 } 1788 1789 TEST_F(TRACE_syscall, ptrace_syscall_redirected) 1790 { 1791 /* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */ 1792 teardown_trace_fixture(_metadata, self->tracer); 1793 self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL, 1794 true); 1795 1796 /* Tracer will redirect getpid to getppid. */ 1797 EXPECT_NE(self->mypid, syscall(__NR_getpid)); 1798 } 1799 1800 TEST_F(TRACE_syscall, ptrace_syscall_dropped) 1801 { 1802 /* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */ 1803 teardown_trace_fixture(_metadata, self->tracer); 1804 self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL, 1805 true); 1806 1807 /* Tracer should skip the open syscall, resulting in EPERM. */ 1808 EXPECT_SYSCALL_RETURN(EPERM, syscall(__NR_openat)); 1809 } 1810 1811 TEST_F(TRACE_syscall, syscall_allowed) 1812 { 1813 long ret; 1814 1815 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1816 ASSERT_EQ(0, ret); 1817 1818 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); 1819 ASSERT_EQ(0, ret); 1820 1821 /* getppid works as expected (no changes). */ 1822 EXPECT_EQ(self->parent, syscall(__NR_getppid)); 1823 EXPECT_NE(self->mypid, syscall(__NR_getppid)); 1824 } 1825 1826 TEST_F(TRACE_syscall, syscall_redirected) 1827 { 1828 long ret; 1829 1830 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1831 ASSERT_EQ(0, ret); 1832 1833 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); 1834 ASSERT_EQ(0, ret); 1835 1836 /* getpid has been redirected to getppid as expected. */ 1837 EXPECT_EQ(self->parent, syscall(__NR_getpid)); 1838 EXPECT_NE(self->mypid, syscall(__NR_getpid)); 1839 } 1840 1841 TEST_F(TRACE_syscall, syscall_dropped) 1842 { 1843 long ret; 1844 1845 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1846 ASSERT_EQ(0, ret); 1847 1848 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); 1849 ASSERT_EQ(0, ret); 1850 1851 /* gettid has been skipped and an altered return value stored. */ 1852 EXPECT_SYSCALL_RETURN(EPERM, syscall(__NR_gettid)); 1853 EXPECT_NE(self->mytid, syscall(__NR_gettid)); 1854 } 1855 1856 TEST_F(TRACE_syscall, skip_after_RET_TRACE) 1857 { 1858 struct sock_filter filter[] = { 1859 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 1860 offsetof(struct seccomp_data, nr)), 1861 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1), 1862 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | EPERM), 1863 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1864 }; 1865 struct sock_fprog prog = { 1866 .len = (unsigned short)ARRAY_SIZE(filter), 1867 .filter = filter, 1868 }; 1869 long ret; 1870 1871 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1872 ASSERT_EQ(0, ret); 1873 1874 /* Install fixture filter. */ 1875 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); 1876 ASSERT_EQ(0, ret); 1877 1878 /* Install "errno on getppid" filter. */ 1879 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 1880 ASSERT_EQ(0, ret); 1881 1882 /* Tracer will redirect getpid to getppid, and we should see EPERM. */ 1883 errno = 0; 1884 EXPECT_EQ(-1, syscall(__NR_getpid)); 1885 EXPECT_EQ(EPERM, errno); 1886 } 1887 1888 TEST_F_SIGNAL(TRACE_syscall, kill_after_RET_TRACE, SIGSYS) 1889 { 1890 struct sock_filter filter[] = { 1891 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 1892 offsetof(struct seccomp_data, nr)), 1893 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1), 1894 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 1895 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1896 }; 1897 struct sock_fprog prog = { 1898 .len = (unsigned short)ARRAY_SIZE(filter), 1899 .filter = filter, 1900 }; 1901 long ret; 1902 1903 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1904 ASSERT_EQ(0, ret); 1905 1906 /* Install fixture filter. */ 1907 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); 1908 ASSERT_EQ(0, ret); 1909 1910 /* Install "death on getppid" filter. */ 1911 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 1912 ASSERT_EQ(0, ret); 1913 1914 /* Tracer will redirect getpid to getppid, and we should die. */ 1915 EXPECT_NE(self->mypid, syscall(__NR_getpid)); 1916 } 1917 1918 TEST_F(TRACE_syscall, skip_after_ptrace) 1919 { 1920 struct sock_filter filter[] = { 1921 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 1922 offsetof(struct seccomp_data, nr)), 1923 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1), 1924 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | EPERM), 1925 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1926 }; 1927 struct sock_fprog prog = { 1928 .len = (unsigned short)ARRAY_SIZE(filter), 1929 .filter = filter, 1930 }; 1931 long ret; 1932 1933 /* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */ 1934 teardown_trace_fixture(_metadata, self->tracer); 1935 self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL, 1936 true); 1937 1938 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1939 ASSERT_EQ(0, ret); 1940 1941 /* Install "errno on getppid" filter. */ 1942 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 1943 ASSERT_EQ(0, ret); 1944 1945 /* Tracer will redirect getpid to getppid, and we should see EPERM. */ 1946 EXPECT_EQ(-1, syscall(__NR_getpid)); 1947 EXPECT_EQ(EPERM, errno); 1948 } 1949 1950 TEST_F_SIGNAL(TRACE_syscall, kill_after_ptrace, SIGSYS) 1951 { 1952 struct sock_filter filter[] = { 1953 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 1954 offsetof(struct seccomp_data, nr)), 1955 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1), 1956 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 1957 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1958 }; 1959 struct sock_fprog prog = { 1960 .len = (unsigned short)ARRAY_SIZE(filter), 1961 .filter = filter, 1962 }; 1963 long ret; 1964 1965 /* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */ 1966 teardown_trace_fixture(_metadata, self->tracer); 1967 self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL, 1968 true); 1969 1970 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1971 ASSERT_EQ(0, ret); 1972 1973 /* Install "death on getppid" filter. */ 1974 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 1975 ASSERT_EQ(0, ret); 1976 1977 /* Tracer will redirect getpid to getppid, and we should die. */ 1978 EXPECT_NE(self->mypid, syscall(__NR_getpid)); 1979 } 1980 1981 TEST(seccomp_syscall) 1982 { 1983 struct sock_filter filter[] = { 1984 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1985 }; 1986 struct sock_fprog prog = { 1987 .len = (unsigned short)ARRAY_SIZE(filter), 1988 .filter = filter, 1989 }; 1990 long ret; 1991 1992 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1993 ASSERT_EQ(0, ret) { 1994 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1995 } 1996 1997 /* Reject insane operation. */ 1998 ret = seccomp(-1, 0, &prog); 1999 ASSERT_NE(ENOSYS, errno) { 2000 TH_LOG("Kernel does not support seccomp syscall!"); 2001 } 2002 EXPECT_EQ(EINVAL, errno) { 2003 TH_LOG("Did not reject crazy op value!"); 2004 } 2005 2006 /* Reject strict with flags or pointer. */ 2007 ret = seccomp(SECCOMP_SET_MODE_STRICT, -1, NULL); 2008 EXPECT_EQ(EINVAL, errno) { 2009 TH_LOG("Did not reject mode strict with flags!"); 2010 } 2011 ret = seccomp(SECCOMP_SET_MODE_STRICT, 0, &prog); 2012 EXPECT_EQ(EINVAL, errno) { 2013 TH_LOG("Did not reject mode strict with uargs!"); 2014 } 2015 2016 /* Reject insane args for filter. */ 2017 ret = seccomp(SECCOMP_SET_MODE_FILTER, -1, &prog); 2018 EXPECT_EQ(EINVAL, errno) { 2019 TH_LOG("Did not reject crazy filter flags!"); 2020 } 2021 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, NULL); 2022 EXPECT_EQ(EFAULT, errno) { 2023 TH_LOG("Did not reject NULL filter!"); 2024 } 2025 2026 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog); 2027 EXPECT_EQ(0, errno) { 2028 TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER: %s", 2029 strerror(errno)); 2030 } 2031 } 2032 2033 TEST(seccomp_syscall_mode_lock) 2034 { 2035 struct sock_filter filter[] = { 2036 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 2037 }; 2038 struct sock_fprog prog = { 2039 .len = (unsigned short)ARRAY_SIZE(filter), 2040 .filter = filter, 2041 }; 2042 long ret; 2043 2044 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, NULL, 0, 0); 2045 ASSERT_EQ(0, ret) { 2046 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 2047 } 2048 2049 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog); 2050 ASSERT_NE(ENOSYS, errno) { 2051 TH_LOG("Kernel does not support seccomp syscall!"); 2052 } 2053 EXPECT_EQ(0, ret) { 2054 TH_LOG("Could not install filter!"); 2055 } 2056 2057 /* Make sure neither entry point will switch to strict. */ 2058 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT, 0, 0, 0); 2059 EXPECT_EQ(EINVAL, errno) { 2060 TH_LOG("Switched to mode strict!"); 2061 } 2062 2063 ret = seccomp(SECCOMP_SET_MODE_STRICT, 0, NULL); 2064 EXPECT_EQ(EINVAL, errno) { 2065 TH_LOG("Switched to mode strict!"); 2066 } 2067 } 2068 2069 /* 2070 * Test detection of known and unknown filter flags. Userspace needs to be able 2071 * to check if a filter flag is supported by the current kernel and a good way 2072 * of doing that is by attempting to enter filter mode, with the flag bit in 2073 * question set, and a NULL pointer for the _args_ parameter. EFAULT indicates 2074 * that the flag is valid and EINVAL indicates that the flag is invalid. 2075 */ 2076 TEST(detect_seccomp_filter_flags) 2077 { 2078 unsigned int flags[] = { SECCOMP_FILTER_FLAG_TSYNC, 2079 SECCOMP_FILTER_FLAG_LOG, 2080 SECCOMP_FILTER_FLAG_SPEC_ALLOW }; 2081 unsigned int flag, all_flags; 2082 int i; 2083 long ret; 2084 2085 /* Test detection of known-good filter flags */ 2086 for (i = 0, all_flags = 0; i < ARRAY_SIZE(flags); i++) { 2087 int bits = 0; 2088 2089 flag = flags[i]; 2090 /* Make sure the flag is a single bit! */ 2091 while (flag) { 2092 if (flag & 0x1) 2093 bits ++; 2094 flag >>= 1; 2095 } 2096 ASSERT_EQ(1, bits); 2097 flag = flags[i]; 2098 2099 ret = seccomp(SECCOMP_SET_MODE_FILTER, flag, NULL); 2100 ASSERT_NE(ENOSYS, errno) { 2101 TH_LOG("Kernel does not support seccomp syscall!"); 2102 } 2103 EXPECT_EQ(-1, ret); 2104 EXPECT_EQ(EFAULT, errno) { 2105 TH_LOG("Failed to detect that a known-good filter flag (0x%X) is supported!", 2106 flag); 2107 } 2108 2109 all_flags |= flag; 2110 } 2111 2112 /* Test detection of all known-good filter flags */ 2113 ret = seccomp(SECCOMP_SET_MODE_FILTER, all_flags, NULL); 2114 EXPECT_EQ(-1, ret); 2115 EXPECT_EQ(EFAULT, errno) { 2116 TH_LOG("Failed to detect that all known-good filter flags (0x%X) are supported!", 2117 all_flags); 2118 } 2119 2120 /* Test detection of an unknown filter flag */ 2121 flag = -1; 2122 ret = seccomp(SECCOMP_SET_MODE_FILTER, flag, NULL); 2123 EXPECT_EQ(-1, ret); 2124 EXPECT_EQ(EINVAL, errno) { 2125 TH_LOG("Failed to detect that an unknown filter flag (0x%X) is unsupported!", 2126 flag); 2127 } 2128 2129 /* 2130 * Test detection of an unknown filter flag that may simply need to be 2131 * added to this test 2132 */ 2133 flag = flags[ARRAY_SIZE(flags) - 1] << 1; 2134 ret = seccomp(SECCOMP_SET_MODE_FILTER, flag, NULL); 2135 EXPECT_EQ(-1, ret); 2136 EXPECT_EQ(EINVAL, errno) { 2137 TH_LOG("Failed to detect that an unknown filter flag (0x%X) is unsupported! Does a new flag need to be added to this test?", 2138 flag); 2139 } 2140 } 2141 2142 TEST(TSYNC_first) 2143 { 2144 struct sock_filter filter[] = { 2145 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 2146 }; 2147 struct sock_fprog prog = { 2148 .len = (unsigned short)ARRAY_SIZE(filter), 2149 .filter = filter, 2150 }; 2151 long ret; 2152 2153 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, NULL, 0, 0); 2154 ASSERT_EQ(0, ret) { 2155 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 2156 } 2157 2158 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC, 2159 &prog); 2160 ASSERT_NE(ENOSYS, errno) { 2161 TH_LOG("Kernel does not support seccomp syscall!"); 2162 } 2163 EXPECT_EQ(0, ret) { 2164 TH_LOG("Could not install initial filter with TSYNC!"); 2165 } 2166 } 2167 2168 #define TSYNC_SIBLINGS 2 2169 struct tsync_sibling { 2170 pthread_t tid; 2171 pid_t system_tid; 2172 sem_t *started; 2173 pthread_cond_t *cond; 2174 pthread_mutex_t *mutex; 2175 int diverge; 2176 int num_waits; 2177 struct sock_fprog *prog; 2178 struct __test_metadata *metadata; 2179 }; 2180 2181 /* 2182 * To avoid joining joined threads (which is not allowed by Bionic), 2183 * make sure we both successfully join and clear the tid to skip a 2184 * later join attempt during fixture teardown. Any remaining threads 2185 * will be directly killed during teardown. 2186 */ 2187 #define PTHREAD_JOIN(tid, status) \ 2188 do { \ 2189 int _rc = pthread_join(tid, status); \ 2190 if (_rc) { \ 2191 TH_LOG("pthread_join of tid %u failed: %d\n", \ 2192 (unsigned int)tid, _rc); \ 2193 } else { \ 2194 tid = 0; \ 2195 } \ 2196 } while (0) 2197 2198 FIXTURE_DATA(TSYNC) { 2199 struct sock_fprog root_prog, apply_prog; 2200 struct tsync_sibling sibling[TSYNC_SIBLINGS]; 2201 sem_t started; 2202 pthread_cond_t cond; 2203 pthread_mutex_t mutex; 2204 int sibling_count; 2205 }; 2206 2207 FIXTURE_SETUP(TSYNC) 2208 { 2209 struct sock_filter root_filter[] = { 2210 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 2211 }; 2212 struct sock_filter apply_filter[] = { 2213 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 2214 offsetof(struct seccomp_data, nr)), 2215 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1), 2216 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 2217 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 2218 }; 2219 2220 memset(&self->root_prog, 0, sizeof(self->root_prog)); 2221 memset(&self->apply_prog, 0, sizeof(self->apply_prog)); 2222 memset(&self->sibling, 0, sizeof(self->sibling)); 2223 self->root_prog.filter = malloc(sizeof(root_filter)); 2224 ASSERT_NE(NULL, self->root_prog.filter); 2225 memcpy(self->root_prog.filter, &root_filter, sizeof(root_filter)); 2226 self->root_prog.len = (unsigned short)ARRAY_SIZE(root_filter); 2227 2228 self->apply_prog.filter = malloc(sizeof(apply_filter)); 2229 ASSERT_NE(NULL, self->apply_prog.filter); 2230 memcpy(self->apply_prog.filter, &apply_filter, sizeof(apply_filter)); 2231 self->apply_prog.len = (unsigned short)ARRAY_SIZE(apply_filter); 2232 2233 self->sibling_count = 0; 2234 pthread_mutex_init(&self->mutex, NULL); 2235 pthread_cond_init(&self->cond, NULL); 2236 sem_init(&self->started, 0, 0); 2237 self->sibling[0].tid = 0; 2238 self->sibling[0].cond = &self->cond; 2239 self->sibling[0].started = &self->started; 2240 self->sibling[0].mutex = &self->mutex; 2241 self->sibling[0].diverge = 0; 2242 self->sibling[0].num_waits = 1; 2243 self->sibling[0].prog = &self->root_prog; 2244 self->sibling[0].metadata = _metadata; 2245 self->sibling[1].tid = 0; 2246 self->sibling[1].cond = &self->cond; 2247 self->sibling[1].started = &self->started; 2248 self->sibling[1].mutex = &self->mutex; 2249 self->sibling[1].diverge = 0; 2250 self->sibling[1].prog = &self->root_prog; 2251 self->sibling[1].num_waits = 1; 2252 self->sibling[1].metadata = _metadata; 2253 } 2254 2255 FIXTURE_TEARDOWN(TSYNC) 2256 { 2257 int sib = 0; 2258 2259 if (self->root_prog.filter) 2260 free(self->root_prog.filter); 2261 if (self->apply_prog.filter) 2262 free(self->apply_prog.filter); 2263 2264 for ( ; sib < self->sibling_count; ++sib) { 2265 struct tsync_sibling *s = &self->sibling[sib]; 2266 2267 if (!s->tid) 2268 continue; 2269 /* 2270 * If a thread is still running, it may be stuck, so hit 2271 * it over the head really hard. 2272 */ 2273 pthread_kill(s->tid, 9); 2274 } 2275 pthread_mutex_destroy(&self->mutex); 2276 pthread_cond_destroy(&self->cond); 2277 sem_destroy(&self->started); 2278 } 2279 2280 void *tsync_sibling(void *data) 2281 { 2282 long ret = 0; 2283 struct tsync_sibling *me = data; 2284 2285 me->system_tid = syscall(__NR_gettid); 2286 2287 pthread_mutex_lock(me->mutex); 2288 if (me->diverge) { 2289 /* Just re-apply the root prog to fork the tree */ 2290 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, 2291 me->prog, 0, 0); 2292 } 2293 sem_post(me->started); 2294 /* Return outside of started so parent notices failures. */ 2295 if (ret) { 2296 pthread_mutex_unlock(me->mutex); 2297 return (void *)SIBLING_EXIT_FAILURE; 2298 } 2299 do { 2300 pthread_cond_wait(me->cond, me->mutex); 2301 me->num_waits = me->num_waits - 1; 2302 } while (me->num_waits); 2303 pthread_mutex_unlock(me->mutex); 2304 2305 ret = prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0); 2306 if (!ret) 2307 return (void *)SIBLING_EXIT_NEWPRIVS; 2308 read(0, NULL, 0); 2309 return (void *)SIBLING_EXIT_UNKILLED; 2310 } 2311 2312 void tsync_start_sibling(struct tsync_sibling *sibling) 2313 { 2314 pthread_create(&sibling->tid, NULL, tsync_sibling, (void *)sibling); 2315 } 2316 2317 TEST_F(TSYNC, siblings_fail_prctl) 2318 { 2319 long ret; 2320 void *status; 2321 struct sock_filter filter[] = { 2322 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 2323 offsetof(struct seccomp_data, nr)), 2324 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_prctl, 0, 1), 2325 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | EINVAL), 2326 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 2327 }; 2328 struct sock_fprog prog = { 2329 .len = (unsigned short)ARRAY_SIZE(filter), 2330 .filter = filter, 2331 }; 2332 2333 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 2334 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 2335 } 2336 2337 /* Check prctl failure detection by requesting sib 0 diverge. */ 2338 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog); 2339 ASSERT_NE(ENOSYS, errno) { 2340 TH_LOG("Kernel does not support seccomp syscall!"); 2341 } 2342 ASSERT_EQ(0, ret) { 2343 TH_LOG("setting filter failed"); 2344 } 2345 2346 self->sibling[0].diverge = 1; 2347 tsync_start_sibling(&self->sibling[0]); 2348 tsync_start_sibling(&self->sibling[1]); 2349 2350 while (self->sibling_count < TSYNC_SIBLINGS) { 2351 sem_wait(&self->started); 2352 self->sibling_count++; 2353 } 2354 2355 /* Signal the threads to clean up*/ 2356 pthread_mutex_lock(&self->mutex); 2357 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 2358 TH_LOG("cond broadcast non-zero"); 2359 } 2360 pthread_mutex_unlock(&self->mutex); 2361 2362 /* Ensure diverging sibling failed to call prctl. */ 2363 PTHREAD_JOIN(self->sibling[0].tid, &status); 2364 EXPECT_EQ(SIBLING_EXIT_FAILURE, (long)status); 2365 PTHREAD_JOIN(self->sibling[1].tid, &status); 2366 EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status); 2367 } 2368 2369 TEST_F(TSYNC, two_siblings_with_ancestor) 2370 { 2371 long ret; 2372 void *status; 2373 2374 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 2375 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 2376 } 2377 2378 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &self->root_prog); 2379 ASSERT_NE(ENOSYS, errno) { 2380 TH_LOG("Kernel does not support seccomp syscall!"); 2381 } 2382 ASSERT_EQ(0, ret) { 2383 TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER!"); 2384 } 2385 tsync_start_sibling(&self->sibling[0]); 2386 tsync_start_sibling(&self->sibling[1]); 2387 2388 while (self->sibling_count < TSYNC_SIBLINGS) { 2389 sem_wait(&self->started); 2390 self->sibling_count++; 2391 } 2392 2393 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC, 2394 &self->apply_prog); 2395 ASSERT_EQ(0, ret) { 2396 TH_LOG("Could install filter on all threads!"); 2397 } 2398 /* Tell the siblings to test the policy */ 2399 pthread_mutex_lock(&self->mutex); 2400 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 2401 TH_LOG("cond broadcast non-zero"); 2402 } 2403 pthread_mutex_unlock(&self->mutex); 2404 /* Ensure they are both killed and don't exit cleanly. */ 2405 PTHREAD_JOIN(self->sibling[0].tid, &status); 2406 EXPECT_EQ(0x0, (long)status); 2407 PTHREAD_JOIN(self->sibling[1].tid, &status); 2408 EXPECT_EQ(0x0, (long)status); 2409 } 2410 2411 TEST_F(TSYNC, two_sibling_want_nnp) 2412 { 2413 void *status; 2414 2415 /* start siblings before any prctl() operations */ 2416 tsync_start_sibling(&self->sibling[0]); 2417 tsync_start_sibling(&self->sibling[1]); 2418 while (self->sibling_count < TSYNC_SIBLINGS) { 2419 sem_wait(&self->started); 2420 self->sibling_count++; 2421 } 2422 2423 /* Tell the siblings to test no policy */ 2424 pthread_mutex_lock(&self->mutex); 2425 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 2426 TH_LOG("cond broadcast non-zero"); 2427 } 2428 pthread_mutex_unlock(&self->mutex); 2429 2430 /* Ensure they are both upset about lacking nnp. */ 2431 PTHREAD_JOIN(self->sibling[0].tid, &status); 2432 EXPECT_EQ(SIBLING_EXIT_NEWPRIVS, (long)status); 2433 PTHREAD_JOIN(self->sibling[1].tid, &status); 2434 EXPECT_EQ(SIBLING_EXIT_NEWPRIVS, (long)status); 2435 } 2436 2437 TEST_F(TSYNC, two_siblings_with_no_filter) 2438 { 2439 long ret; 2440 void *status; 2441 2442 /* start siblings before any prctl() operations */ 2443 tsync_start_sibling(&self->sibling[0]); 2444 tsync_start_sibling(&self->sibling[1]); 2445 while (self->sibling_count < TSYNC_SIBLINGS) { 2446 sem_wait(&self->started); 2447 self->sibling_count++; 2448 } 2449 2450 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 2451 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 2452 } 2453 2454 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC, 2455 &self->apply_prog); 2456 ASSERT_NE(ENOSYS, errno) { 2457 TH_LOG("Kernel does not support seccomp syscall!"); 2458 } 2459 ASSERT_EQ(0, ret) { 2460 TH_LOG("Could install filter on all threads!"); 2461 } 2462 2463 /* Tell the siblings to test the policy */ 2464 pthread_mutex_lock(&self->mutex); 2465 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 2466 TH_LOG("cond broadcast non-zero"); 2467 } 2468 pthread_mutex_unlock(&self->mutex); 2469 2470 /* Ensure they are both killed and don't exit cleanly. */ 2471 PTHREAD_JOIN(self->sibling[0].tid, &status); 2472 EXPECT_EQ(0x0, (long)status); 2473 PTHREAD_JOIN(self->sibling[1].tid, &status); 2474 EXPECT_EQ(0x0, (long)status); 2475 } 2476 2477 TEST_F(TSYNC, two_siblings_with_one_divergence) 2478 { 2479 long ret; 2480 void *status; 2481 2482 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 2483 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 2484 } 2485 2486 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &self->root_prog); 2487 ASSERT_NE(ENOSYS, errno) { 2488 TH_LOG("Kernel does not support seccomp syscall!"); 2489 } 2490 ASSERT_EQ(0, ret) { 2491 TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER!"); 2492 } 2493 self->sibling[0].diverge = 1; 2494 tsync_start_sibling(&self->sibling[0]); 2495 tsync_start_sibling(&self->sibling[1]); 2496 2497 while (self->sibling_count < TSYNC_SIBLINGS) { 2498 sem_wait(&self->started); 2499 self->sibling_count++; 2500 } 2501 2502 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC, 2503 &self->apply_prog); 2504 ASSERT_EQ(self->sibling[0].system_tid, ret) { 2505 TH_LOG("Did not fail on diverged sibling."); 2506 } 2507 2508 /* Wake the threads */ 2509 pthread_mutex_lock(&self->mutex); 2510 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 2511 TH_LOG("cond broadcast non-zero"); 2512 } 2513 pthread_mutex_unlock(&self->mutex); 2514 2515 /* Ensure they are both unkilled. */ 2516 PTHREAD_JOIN(self->sibling[0].tid, &status); 2517 EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status); 2518 PTHREAD_JOIN(self->sibling[1].tid, &status); 2519 EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status); 2520 } 2521 2522 TEST_F(TSYNC, two_siblings_not_under_filter) 2523 { 2524 long ret, sib; 2525 void *status; 2526 2527 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 2528 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 2529 } 2530 2531 /* 2532 * Sibling 0 will have its own seccomp policy 2533 * and Sibling 1 will not be under seccomp at 2534 * all. Sibling 1 will enter seccomp and 0 2535 * will cause failure. 2536 */ 2537 self->sibling[0].diverge = 1; 2538 tsync_start_sibling(&self->sibling[0]); 2539 tsync_start_sibling(&self->sibling[1]); 2540 2541 while (self->sibling_count < TSYNC_SIBLINGS) { 2542 sem_wait(&self->started); 2543 self->sibling_count++; 2544 } 2545 2546 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &self->root_prog); 2547 ASSERT_NE(ENOSYS, errno) { 2548 TH_LOG("Kernel does not support seccomp syscall!"); 2549 } 2550 ASSERT_EQ(0, ret) { 2551 TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER!"); 2552 } 2553 2554 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC, 2555 &self->apply_prog); 2556 ASSERT_EQ(ret, self->sibling[0].system_tid) { 2557 TH_LOG("Did not fail on diverged sibling."); 2558 } 2559 sib = 1; 2560 if (ret == self->sibling[0].system_tid) 2561 sib = 0; 2562 2563 pthread_mutex_lock(&self->mutex); 2564 2565 /* Increment the other siblings num_waits so we can clean up 2566 * the one we just saw. 2567 */ 2568 self->sibling[!sib].num_waits += 1; 2569 2570 /* Signal the thread to clean up*/ 2571 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 2572 TH_LOG("cond broadcast non-zero"); 2573 } 2574 pthread_mutex_unlock(&self->mutex); 2575 PTHREAD_JOIN(self->sibling[sib].tid, &status); 2576 EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status); 2577 /* Poll for actual task death. pthread_join doesn't guarantee it. */ 2578 while (!kill(self->sibling[sib].system_tid, 0)) 2579 sleep(0.1); 2580 /* Switch to the remaining sibling */ 2581 sib = !sib; 2582 2583 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC, 2584 &self->apply_prog); 2585 ASSERT_EQ(0, ret) { 2586 TH_LOG("Expected the remaining sibling to sync"); 2587 }; 2588 2589 pthread_mutex_lock(&self->mutex); 2590 2591 /* If remaining sibling didn't have a chance to wake up during 2592 * the first broadcast, manually reduce the num_waits now. 2593 */ 2594 if (self->sibling[sib].num_waits > 1) 2595 self->sibling[sib].num_waits = 1; 2596 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 2597 TH_LOG("cond broadcast non-zero"); 2598 } 2599 pthread_mutex_unlock(&self->mutex); 2600 PTHREAD_JOIN(self->sibling[sib].tid, &status); 2601 EXPECT_EQ(0, (long)status); 2602 /* Poll for actual task death. pthread_join doesn't guarantee it. */ 2603 while (!kill(self->sibling[sib].system_tid, 0)) 2604 sleep(0.1); 2605 2606 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC, 2607 &self->apply_prog); 2608 ASSERT_EQ(0, ret); /* just us chickens */ 2609 } 2610 2611 /* Make sure restarted syscalls are seen directly as "restart_syscall". */ 2612 TEST(syscall_restart) 2613 { 2614 long ret; 2615 unsigned long msg; 2616 pid_t child_pid; 2617 int pipefd[2]; 2618 int status; 2619 siginfo_t info = { }; 2620 struct sock_filter filter[] = { 2621 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 2622 offsetof(struct seccomp_data, nr)), 2623 2624 #ifdef __NR_sigreturn 2625 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_sigreturn, 6, 0), 2626 #endif 2627 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 5, 0), 2628 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_exit, 4, 0), 2629 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_rt_sigreturn, 3, 0), 2630 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_nanosleep, 4, 0), 2631 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_restart_syscall, 4, 0), 2632 2633 /* Allow __NR_write for easy logging. */ 2634 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_write, 0, 1), 2635 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 2636 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 2637 /* The nanosleep jump target. */ 2638 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE|0x100), 2639 /* The restart_syscall jump target. */ 2640 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE|0x200), 2641 }; 2642 struct sock_fprog prog = { 2643 .len = (unsigned short)ARRAY_SIZE(filter), 2644 .filter = filter, 2645 }; 2646 #if defined(__arm__) 2647 struct utsname utsbuf; 2648 #endif 2649 2650 ASSERT_EQ(0, pipe(pipefd)); 2651 2652 child_pid = fork(); 2653 ASSERT_LE(0, child_pid); 2654 if (child_pid == 0) { 2655 /* Child uses EXPECT not ASSERT to deliver status correctly. */ 2656 char buf = ' '; 2657 struct timespec timeout = { }; 2658 2659 /* Attach parent as tracer and stop. */ 2660 EXPECT_EQ(0, ptrace(PTRACE_TRACEME)); 2661 EXPECT_EQ(0, raise(SIGSTOP)); 2662 2663 EXPECT_EQ(0, close(pipefd[1])); 2664 2665 EXPECT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 2666 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 2667 } 2668 2669 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 2670 EXPECT_EQ(0, ret) { 2671 TH_LOG("Failed to install filter!"); 2672 } 2673 2674 EXPECT_EQ(1, read(pipefd[0], &buf, 1)) { 2675 TH_LOG("Failed to read() sync from parent"); 2676 } 2677 EXPECT_EQ('.', buf) { 2678 TH_LOG("Failed to get sync data from read()"); 2679 } 2680 2681 /* Start nanosleep to be interrupted. */ 2682 timeout.tv_sec = 1; 2683 errno = 0; 2684 EXPECT_EQ(0, nanosleep(&timeout, NULL)) { 2685 TH_LOG("Call to nanosleep() failed (errno %d)", errno); 2686 } 2687 2688 /* Read final sync from parent. */ 2689 EXPECT_EQ(1, read(pipefd[0], &buf, 1)) { 2690 TH_LOG("Failed final read() from parent"); 2691 } 2692 EXPECT_EQ('!', buf) { 2693 TH_LOG("Failed to get final data from read()"); 2694 } 2695 2696 /* Directly report the status of our test harness results. */ 2697 syscall(__NR_exit, _metadata->passed ? EXIT_SUCCESS 2698 : EXIT_FAILURE); 2699 } 2700 EXPECT_EQ(0, close(pipefd[0])); 2701 2702 /* Attach to child, setup options, and release. */ 2703 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2704 ASSERT_EQ(true, WIFSTOPPED(status)); 2705 ASSERT_EQ(0, ptrace(PTRACE_SETOPTIONS, child_pid, NULL, 2706 PTRACE_O_TRACESECCOMP)); 2707 ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0)); 2708 ASSERT_EQ(1, write(pipefd[1], ".", 1)); 2709 2710 /* Wait for nanosleep() to start. */ 2711 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2712 ASSERT_EQ(true, WIFSTOPPED(status)); 2713 ASSERT_EQ(SIGTRAP, WSTOPSIG(status)); 2714 ASSERT_EQ(PTRACE_EVENT_SECCOMP, (status >> 16)); 2715 ASSERT_EQ(0, ptrace(PTRACE_GETEVENTMSG, child_pid, NULL, &msg)); 2716 ASSERT_EQ(0x100, msg); 2717 EXPECT_EQ(__NR_nanosleep, get_syscall(_metadata, child_pid)); 2718 2719 /* Might as well check siginfo for sanity while we're here. */ 2720 ASSERT_EQ(0, ptrace(PTRACE_GETSIGINFO, child_pid, NULL, &info)); 2721 ASSERT_EQ(SIGTRAP, info.si_signo); 2722 ASSERT_EQ(SIGTRAP | (PTRACE_EVENT_SECCOMP << 8), info.si_code); 2723 EXPECT_EQ(0, info.si_errno); 2724 EXPECT_EQ(getuid(), info.si_uid); 2725 /* Verify signal delivery came from child (seccomp-triggered). */ 2726 EXPECT_EQ(child_pid, info.si_pid); 2727 2728 /* Interrupt nanosleep with SIGSTOP (which we'll need to handle). */ 2729 ASSERT_EQ(0, kill(child_pid, SIGSTOP)); 2730 ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0)); 2731 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2732 ASSERT_EQ(true, WIFSTOPPED(status)); 2733 ASSERT_EQ(SIGSTOP, WSTOPSIG(status)); 2734 /* Verify signal delivery came from parent now. */ 2735 ASSERT_EQ(0, ptrace(PTRACE_GETSIGINFO, child_pid, NULL, &info)); 2736 EXPECT_EQ(getpid(), info.si_pid); 2737 2738 /* Restart nanosleep with SIGCONT, which triggers restart_syscall. */ 2739 ASSERT_EQ(0, kill(child_pid, SIGCONT)); 2740 ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0)); 2741 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2742 ASSERT_EQ(true, WIFSTOPPED(status)); 2743 ASSERT_EQ(SIGCONT, WSTOPSIG(status)); 2744 ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0)); 2745 2746 /* Wait for restart_syscall() to start. */ 2747 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2748 ASSERT_EQ(true, WIFSTOPPED(status)); 2749 ASSERT_EQ(SIGTRAP, WSTOPSIG(status)); 2750 ASSERT_EQ(PTRACE_EVENT_SECCOMP, (status >> 16)); 2751 ASSERT_EQ(0, ptrace(PTRACE_GETEVENTMSG, child_pid, NULL, &msg)); 2752 2753 ASSERT_EQ(0x200, msg); 2754 ret = get_syscall(_metadata, child_pid); 2755 #if defined(__arm__) 2756 /* 2757 * FIXME: 2758 * - native ARM registers do NOT expose true syscall. 2759 * - compat ARM registers on ARM64 DO expose true syscall. 2760 */ 2761 ASSERT_EQ(0, uname(&utsbuf)); 2762 if (strncmp(utsbuf.machine, "arm", 3) == 0) { 2763 EXPECT_EQ(__NR_nanosleep, ret); 2764 } else 2765 #endif 2766 { 2767 EXPECT_EQ(__NR_restart_syscall, ret); 2768 } 2769 2770 /* Write again to end test. */ 2771 ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0)); 2772 ASSERT_EQ(1, write(pipefd[1], "!", 1)); 2773 EXPECT_EQ(0, close(pipefd[1])); 2774 2775 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2776 if (WIFSIGNALED(status) || WEXITSTATUS(status)) 2777 _metadata->passed = 0; 2778 } 2779 2780 TEST_SIGNAL(filter_flag_log, SIGSYS) 2781 { 2782 struct sock_filter allow_filter[] = { 2783 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 2784 }; 2785 struct sock_filter kill_filter[] = { 2786 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 2787 offsetof(struct seccomp_data, nr)), 2788 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 0, 1), 2789 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 2790 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 2791 }; 2792 struct sock_fprog allow_prog = { 2793 .len = (unsigned short)ARRAY_SIZE(allow_filter), 2794 .filter = allow_filter, 2795 }; 2796 struct sock_fprog kill_prog = { 2797 .len = (unsigned short)ARRAY_SIZE(kill_filter), 2798 .filter = kill_filter, 2799 }; 2800 long ret; 2801 pid_t parent = getppid(); 2802 2803 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 2804 ASSERT_EQ(0, ret); 2805 2806 /* Verify that the FILTER_FLAG_LOG flag isn't accepted in strict mode */ 2807 ret = seccomp(SECCOMP_SET_MODE_STRICT, SECCOMP_FILTER_FLAG_LOG, 2808 &allow_prog); 2809 ASSERT_NE(ENOSYS, errno) { 2810 TH_LOG("Kernel does not support seccomp syscall!"); 2811 } 2812 EXPECT_NE(0, ret) { 2813 TH_LOG("Kernel accepted FILTER_FLAG_LOG flag in strict mode!"); 2814 } 2815 EXPECT_EQ(EINVAL, errno) { 2816 TH_LOG("Kernel returned unexpected errno for FILTER_FLAG_LOG flag in strict mode!"); 2817 } 2818 2819 /* Verify that a simple, permissive filter can be added with no flags */ 2820 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &allow_prog); 2821 EXPECT_EQ(0, ret); 2822 2823 /* See if the same filter can be added with the FILTER_FLAG_LOG flag */ 2824 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_LOG, 2825 &allow_prog); 2826 ASSERT_NE(EINVAL, errno) { 2827 TH_LOG("Kernel does not support the FILTER_FLAG_LOG flag!"); 2828 } 2829 EXPECT_EQ(0, ret); 2830 2831 /* Ensure that the kill filter works with the FILTER_FLAG_LOG flag */ 2832 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_LOG, 2833 &kill_prog); 2834 EXPECT_EQ(0, ret); 2835 2836 EXPECT_EQ(parent, syscall(__NR_getppid)); 2837 /* getpid() should never return. */ 2838 EXPECT_EQ(0, syscall(__NR_getpid)); 2839 } 2840 2841 TEST(get_action_avail) 2842 { 2843 __u32 actions[] = { SECCOMP_RET_KILL_THREAD, SECCOMP_RET_TRAP, 2844 SECCOMP_RET_ERRNO, SECCOMP_RET_TRACE, 2845 SECCOMP_RET_LOG, SECCOMP_RET_ALLOW }; 2846 __u32 unknown_action = 0x10000000U; 2847 int i; 2848 long ret; 2849 2850 ret = seccomp(SECCOMP_GET_ACTION_AVAIL, 0, &actions[0]); 2851 ASSERT_NE(ENOSYS, errno) { 2852 TH_LOG("Kernel does not support seccomp syscall!"); 2853 } 2854 ASSERT_NE(EINVAL, errno) { 2855 TH_LOG("Kernel does not support SECCOMP_GET_ACTION_AVAIL operation!"); 2856 } 2857 EXPECT_EQ(ret, 0); 2858 2859 for (i = 0; i < ARRAY_SIZE(actions); i++) { 2860 ret = seccomp(SECCOMP_GET_ACTION_AVAIL, 0, &actions[i]); 2861 EXPECT_EQ(ret, 0) { 2862 TH_LOG("Expected action (0x%X) not available!", 2863 actions[i]); 2864 } 2865 } 2866 2867 /* Check that an unknown action is handled properly (EOPNOTSUPP) */ 2868 ret = seccomp(SECCOMP_GET_ACTION_AVAIL, 0, &unknown_action); 2869 EXPECT_EQ(ret, -1); 2870 EXPECT_EQ(errno, EOPNOTSUPP); 2871 } 2872 2873 TEST(get_metadata) 2874 { 2875 pid_t pid; 2876 int pipefd[2]; 2877 char buf; 2878 struct seccomp_metadata md; 2879 long ret; 2880 2881 ASSERT_EQ(0, pipe(pipefd)); 2882 2883 pid = fork(); 2884 ASSERT_GE(pid, 0); 2885 if (pid == 0) { 2886 struct sock_filter filter[] = { 2887 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 2888 }; 2889 struct sock_fprog prog = { 2890 .len = (unsigned short)ARRAY_SIZE(filter), 2891 .filter = filter, 2892 }; 2893 2894 /* one with log, one without */ 2895 ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 2896 SECCOMP_FILTER_FLAG_LOG, &prog)); 2897 ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog)); 2898 2899 ASSERT_EQ(0, close(pipefd[0])); 2900 ASSERT_EQ(1, write(pipefd[1], "1", 1)); 2901 ASSERT_EQ(0, close(pipefd[1])); 2902 2903 while (1) 2904 sleep(100); 2905 } 2906 2907 ASSERT_EQ(0, close(pipefd[1])); 2908 ASSERT_EQ(1, read(pipefd[0], &buf, 1)); 2909 2910 ASSERT_EQ(0, ptrace(PTRACE_ATTACH, pid)); 2911 ASSERT_EQ(pid, waitpid(pid, NULL, 0)); 2912 2913 /* Past here must not use ASSERT or child process is never killed. */ 2914 2915 md.filter_off = 0; 2916 errno = 0; 2917 ret = ptrace(PTRACE_SECCOMP_GET_METADATA, pid, sizeof(md), &md); 2918 EXPECT_EQ(sizeof(md), ret) { 2919 if (errno == EINVAL) 2920 XFAIL(goto skip, "Kernel does not support PTRACE_SECCOMP_GET_METADATA (missing CONFIG_CHECKPOINT_RESTORE?)"); 2921 } 2922 2923 EXPECT_EQ(md.flags, SECCOMP_FILTER_FLAG_LOG); 2924 EXPECT_EQ(md.filter_off, 0); 2925 2926 md.filter_off = 1; 2927 ret = ptrace(PTRACE_SECCOMP_GET_METADATA, pid, sizeof(md), &md); 2928 EXPECT_EQ(sizeof(md), ret); 2929 EXPECT_EQ(md.flags, 0); 2930 EXPECT_EQ(md.filter_off, 1); 2931 2932 skip: 2933 ASSERT_EQ(0, kill(pid, SIGKILL)); 2934 } 2935 2936 /* 2937 * TODO: 2938 * - add microbenchmarks 2939 * - expand NNP testing 2940 * - better arch-specific TRACE and TRAP handlers. 2941 * - endianness checking when appropriate 2942 * - 64-bit arg prodding 2943 * - arch value testing (x86 modes especially) 2944 * - verify that FILTER_FLAG_LOG filters generate log messages 2945 * - verify that RET_LOG generates log messages 2946 * - ... 2947 */ 2948 2949 TEST_HARNESS_MAIN 2950