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 <asm/siginfo.h> 9 #define __have_siginfo_t 1 10 #define __have_sigval_t 1 11 #define __have_sigevent_t 1 12 13 #include <errno.h> 14 #include <linux/filter.h> 15 #include <sys/prctl.h> 16 #include <sys/ptrace.h> 17 #include <sys/types.h> 18 #include <sys/user.h> 19 #include <linux/prctl.h> 20 #include <linux/ptrace.h> 21 #include <linux/seccomp.h> 22 #include <pthread.h> 23 #include <semaphore.h> 24 #include <signal.h> 25 #include <stddef.h> 26 #include <stdbool.h> 27 #include <string.h> 28 #include <time.h> 29 #include <linux/elf.h> 30 #include <sys/uio.h> 31 #include <sys/utsname.h> 32 #include <sys/fcntl.h> 33 #include <sys/mman.h> 34 #include <sys/times.h> 35 36 #define _GNU_SOURCE 37 #include <unistd.h> 38 #include <sys/syscall.h> 39 40 #include "test_harness.h" 41 42 #ifndef PR_SET_PTRACER 43 # define PR_SET_PTRACER 0x59616d61 44 #endif 45 46 #ifndef PR_SET_NO_NEW_PRIVS 47 #define PR_SET_NO_NEW_PRIVS 38 48 #define PR_GET_NO_NEW_PRIVS 39 49 #endif 50 51 #ifndef PR_SECCOMP_EXT 52 #define PR_SECCOMP_EXT 43 53 #endif 54 55 #ifndef SECCOMP_EXT_ACT 56 #define SECCOMP_EXT_ACT 1 57 #endif 58 59 #ifndef SECCOMP_EXT_ACT_TSYNC 60 #define SECCOMP_EXT_ACT_TSYNC 1 61 #endif 62 63 #ifndef SECCOMP_MODE_STRICT 64 #define SECCOMP_MODE_STRICT 1 65 #endif 66 67 #ifndef SECCOMP_MODE_FILTER 68 #define SECCOMP_MODE_FILTER 2 69 #endif 70 71 #ifndef SECCOMP_RET_KILL 72 #define SECCOMP_RET_KILL 0x00000000U /* kill the task immediately */ 73 #define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */ 74 #define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */ 75 #define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */ 76 #define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */ 77 78 /* Masks for the return value sections. */ 79 #define SECCOMP_RET_ACTION 0x7fff0000U 80 #define SECCOMP_RET_DATA 0x0000ffffU 81 82 struct seccomp_data { 83 int nr; 84 __u32 arch; 85 __u64 instruction_pointer; 86 __u64 args[6]; 87 }; 88 #endif 89 90 #if __BYTE_ORDER == __LITTLE_ENDIAN 91 #define syscall_arg(_n) (offsetof(struct seccomp_data, args[_n])) 92 #elif __BYTE_ORDER == __BIG_ENDIAN 93 #define syscall_arg(_n) (offsetof(struct seccomp_data, args[_n]) + sizeof(__u32)) 94 #else 95 #error "wut? Unknown __BYTE_ORDER?!" 96 #endif 97 98 #define SIBLING_EXIT_UNKILLED 0xbadbeef 99 #define SIBLING_EXIT_FAILURE 0xbadface 100 #define SIBLING_EXIT_NEWPRIVS 0xbadfeed 101 102 TEST(mode_strict_support) 103 { 104 long ret; 105 106 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT, NULL, NULL, NULL); 107 ASSERT_EQ(0, ret) { 108 TH_LOG("Kernel does not support CONFIG_SECCOMP"); 109 } 110 syscall(__NR_exit, 1); 111 } 112 113 TEST_SIGNAL(mode_strict_cannot_call_prctl, SIGKILL) 114 { 115 long ret; 116 117 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT, NULL, NULL, NULL); 118 ASSERT_EQ(0, ret) { 119 TH_LOG("Kernel does not support CONFIG_SECCOMP"); 120 } 121 syscall(__NR_prctl, PR_SET_SECCOMP, SECCOMP_MODE_FILTER, 122 NULL, NULL, NULL); 123 EXPECT_FALSE(true) { 124 TH_LOG("Unreachable!"); 125 } 126 } 127 128 /* Note! This doesn't test no new privs behavior */ 129 TEST(no_new_privs_support) 130 { 131 long ret; 132 133 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 134 EXPECT_EQ(0, ret) { 135 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 136 } 137 } 138 139 /* Tests kernel support by checking for a copy_from_user() fault on * NULL. */ 140 TEST(mode_filter_support) 141 { 142 long ret; 143 144 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, NULL, 0, 0); 145 ASSERT_EQ(0, ret) { 146 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 147 } 148 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, NULL, NULL, NULL); 149 EXPECT_EQ(-1, ret); 150 EXPECT_EQ(EFAULT, errno) { 151 TH_LOG("Kernel does not support CONFIG_SECCOMP_FILTER!"); 152 } 153 } 154 155 TEST(mode_filter_without_nnp) 156 { 157 struct sock_filter filter[] = { 158 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 159 }; 160 struct sock_fprog prog = { 161 .len = (unsigned short)ARRAY_SIZE(filter), 162 .filter = filter, 163 }; 164 long ret; 165 166 ret = prctl(PR_GET_NO_NEW_PRIVS, 0, NULL, 0, 0); 167 ASSERT_LE(0, ret) { 168 TH_LOG("Expected 0 or unsupported for NO_NEW_PRIVS"); 169 } 170 errno = 0; 171 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 172 /* Succeeds with CAP_SYS_ADMIN, fails without */ 173 /* TODO(wad) check caps not euid */ 174 if (geteuid()) { 175 EXPECT_EQ(-1, ret); 176 EXPECT_EQ(EACCES, errno); 177 } else { 178 EXPECT_EQ(0, ret); 179 } 180 } 181 182 #define MAX_INSNS_PER_PATH 32768 183 184 TEST(filter_size_limits) 185 { 186 int i; 187 int count = BPF_MAXINSNS + 1; 188 struct sock_filter allow[] = { 189 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 190 }; 191 struct sock_filter *filter; 192 struct sock_fprog prog = { }; 193 long ret; 194 195 filter = calloc(count, sizeof(*filter)); 196 ASSERT_NE(NULL, filter); 197 198 for (i = 0; i < count; i++) 199 filter[i] = allow[0]; 200 201 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 202 ASSERT_EQ(0, ret); 203 204 prog.filter = filter; 205 prog.len = count; 206 207 /* Too many filter instructions in a single filter. */ 208 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 209 ASSERT_NE(0, ret) { 210 TH_LOG("Installing %d insn filter was allowed", prog.len); 211 } 212 213 /* One less is okay, though. */ 214 prog.len -= 1; 215 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 216 ASSERT_EQ(0, ret) { 217 TH_LOG("Installing %d insn filter wasn't allowed", prog.len); 218 } 219 } 220 221 TEST(filter_chain_limits) 222 { 223 int i; 224 int count = BPF_MAXINSNS; 225 struct sock_filter allow[] = { 226 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 227 }; 228 struct sock_filter *filter; 229 struct sock_fprog prog = { }; 230 long ret; 231 232 filter = calloc(count, sizeof(*filter)); 233 ASSERT_NE(NULL, filter); 234 235 for (i = 0; i < count; i++) 236 filter[i] = allow[0]; 237 238 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 239 ASSERT_EQ(0, ret); 240 241 prog.filter = filter; 242 prog.len = 1; 243 244 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 245 ASSERT_EQ(0, ret); 246 247 prog.len = count; 248 249 /* Too many total filter instructions. */ 250 for (i = 0; i < MAX_INSNS_PER_PATH; i++) { 251 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 252 if (ret != 0) 253 break; 254 } 255 ASSERT_NE(0, ret) { 256 TH_LOG("Allowed %d %d-insn filters (total with penalties:%d)", 257 i, count, i * (count + 4)); 258 } 259 } 260 261 TEST(mode_filter_cannot_move_to_strict) 262 { 263 struct sock_filter filter[] = { 264 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 265 }; 266 struct sock_fprog prog = { 267 .len = (unsigned short)ARRAY_SIZE(filter), 268 .filter = filter, 269 }; 270 long ret; 271 272 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 273 ASSERT_EQ(0, ret); 274 275 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 276 ASSERT_EQ(0, ret); 277 278 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT, NULL, 0, 0); 279 EXPECT_EQ(-1, ret); 280 EXPECT_EQ(EINVAL, errno); 281 } 282 283 284 TEST(mode_filter_get_seccomp) 285 { 286 struct sock_filter filter[] = { 287 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 288 }; 289 struct sock_fprog prog = { 290 .len = (unsigned short)ARRAY_SIZE(filter), 291 .filter = filter, 292 }; 293 long ret; 294 295 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 296 ASSERT_EQ(0, ret); 297 298 ret = prctl(PR_GET_SECCOMP, 0, 0, 0, 0); 299 EXPECT_EQ(0, ret); 300 301 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 302 ASSERT_EQ(0, ret); 303 304 ret = prctl(PR_GET_SECCOMP, 0, 0, 0, 0); 305 EXPECT_EQ(2, ret); 306 } 307 308 309 TEST(ALLOW_all) 310 { 311 struct sock_filter filter[] = { 312 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 313 }; 314 struct sock_fprog prog = { 315 .len = (unsigned short)ARRAY_SIZE(filter), 316 .filter = filter, 317 }; 318 long ret; 319 320 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 321 ASSERT_EQ(0, ret); 322 323 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 324 ASSERT_EQ(0, ret); 325 } 326 327 TEST(empty_prog) 328 { 329 struct sock_filter filter[] = { 330 }; 331 struct sock_fprog prog = { 332 .len = (unsigned short)ARRAY_SIZE(filter), 333 .filter = filter, 334 }; 335 long ret; 336 337 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 338 ASSERT_EQ(0, ret); 339 340 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 341 EXPECT_EQ(-1, ret); 342 EXPECT_EQ(EINVAL, errno); 343 } 344 345 TEST_SIGNAL(unknown_ret_is_kill_inside, SIGSYS) 346 { 347 struct sock_filter filter[] = { 348 BPF_STMT(BPF_RET|BPF_K, 0x10000000U), 349 }; 350 struct sock_fprog prog = { 351 .len = (unsigned short)ARRAY_SIZE(filter), 352 .filter = filter, 353 }; 354 long ret; 355 356 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 357 ASSERT_EQ(0, ret); 358 359 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 360 ASSERT_EQ(0, ret); 361 EXPECT_EQ(0, syscall(__NR_getpid)) { 362 TH_LOG("getpid() shouldn't ever return"); 363 } 364 } 365 366 /* return code >= 0x80000000 is unused. */ 367 TEST_SIGNAL(unknown_ret_is_kill_above_allow, SIGSYS) 368 { 369 struct sock_filter filter[] = { 370 BPF_STMT(BPF_RET|BPF_K, 0x90000000U), 371 }; 372 struct sock_fprog prog = { 373 .len = (unsigned short)ARRAY_SIZE(filter), 374 .filter = filter, 375 }; 376 long ret; 377 378 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 379 ASSERT_EQ(0, ret); 380 381 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 382 ASSERT_EQ(0, ret); 383 EXPECT_EQ(0, syscall(__NR_getpid)) { 384 TH_LOG("getpid() shouldn't ever return"); 385 } 386 } 387 388 TEST_SIGNAL(KILL_all, SIGSYS) 389 { 390 struct sock_filter filter[] = { 391 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 392 }; 393 struct sock_fprog prog = { 394 .len = (unsigned short)ARRAY_SIZE(filter), 395 .filter = filter, 396 }; 397 long ret; 398 399 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 400 ASSERT_EQ(0, ret); 401 402 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 403 ASSERT_EQ(0, ret); 404 } 405 406 TEST_SIGNAL(KILL_one, SIGSYS) 407 { 408 struct sock_filter filter[] = { 409 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 410 offsetof(struct seccomp_data, nr)), 411 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 0, 1), 412 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 413 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 414 }; 415 struct sock_fprog prog = { 416 .len = (unsigned short)ARRAY_SIZE(filter), 417 .filter = filter, 418 }; 419 long ret; 420 pid_t parent = getppid(); 421 422 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 423 ASSERT_EQ(0, ret); 424 425 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 426 ASSERT_EQ(0, ret); 427 428 EXPECT_EQ(parent, syscall(__NR_getppid)); 429 /* getpid() should never return. */ 430 EXPECT_EQ(0, syscall(__NR_getpid)); 431 } 432 433 TEST_SIGNAL(KILL_one_arg_one, SIGSYS) 434 { 435 void *fatal_address; 436 struct sock_filter filter[] = { 437 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 438 offsetof(struct seccomp_data, nr)), 439 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_times, 1, 0), 440 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 441 /* Only both with lower 32-bit for now. */ 442 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, syscall_arg(0)), 443 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 444 (unsigned long)&fatal_address, 0, 1), 445 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 446 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 447 }; 448 struct sock_fprog prog = { 449 .len = (unsigned short)ARRAY_SIZE(filter), 450 .filter = filter, 451 }; 452 long ret; 453 pid_t parent = getppid(); 454 struct tms timebuf; 455 clock_t clock = times(&timebuf); 456 457 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 458 ASSERT_EQ(0, ret); 459 460 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 461 ASSERT_EQ(0, ret); 462 463 EXPECT_EQ(parent, syscall(__NR_getppid)); 464 EXPECT_LE(clock, syscall(__NR_times, &timebuf)); 465 /* times() should never return. */ 466 EXPECT_EQ(0, syscall(__NR_times, &fatal_address)); 467 } 468 469 TEST_SIGNAL(KILL_one_arg_six, SIGSYS) 470 { 471 #ifndef __NR_mmap2 472 int sysno = __NR_mmap; 473 #else 474 int sysno = __NR_mmap2; 475 #endif 476 struct sock_filter filter[] = { 477 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 478 offsetof(struct seccomp_data, nr)), 479 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, sysno, 1, 0), 480 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 481 /* Only both with lower 32-bit for now. */ 482 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, syscall_arg(5)), 483 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 0x0C0FFEE, 0, 1), 484 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 485 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 486 }; 487 struct sock_fprog prog = { 488 .len = (unsigned short)ARRAY_SIZE(filter), 489 .filter = filter, 490 }; 491 long ret; 492 pid_t parent = getppid(); 493 int fd; 494 void *map1, *map2; 495 int page_size = sysconf(_SC_PAGESIZE); 496 497 ASSERT_LT(0, page_size); 498 499 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 500 ASSERT_EQ(0, ret); 501 502 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 503 ASSERT_EQ(0, ret); 504 505 fd = open("/dev/zero", O_RDONLY); 506 ASSERT_NE(-1, fd); 507 508 EXPECT_EQ(parent, syscall(__NR_getppid)); 509 map1 = (void *)syscall(sysno, 510 NULL, page_size, PROT_READ, MAP_PRIVATE, fd, page_size); 511 EXPECT_NE(MAP_FAILED, map1); 512 /* mmap2() should never return. */ 513 map2 = (void *)syscall(sysno, 514 NULL, page_size, PROT_READ, MAP_PRIVATE, fd, 0x0C0FFEE); 515 EXPECT_EQ(MAP_FAILED, map2); 516 517 /* The test failed, so clean up the resources. */ 518 munmap(map1, page_size); 519 munmap(map2, page_size); 520 close(fd); 521 } 522 523 /* TODO(wad) add 64-bit versus 32-bit arg tests. */ 524 TEST(arg_out_of_range) 525 { 526 struct sock_filter filter[] = { 527 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, syscall_arg(6)), 528 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 529 }; 530 struct sock_fprog prog = { 531 .len = (unsigned short)ARRAY_SIZE(filter), 532 .filter = filter, 533 }; 534 long ret; 535 536 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 537 ASSERT_EQ(0, ret); 538 539 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 540 EXPECT_EQ(-1, ret); 541 EXPECT_EQ(EINVAL, errno); 542 } 543 544 TEST(ERRNO_valid) 545 { 546 struct sock_filter filter[] = { 547 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 548 offsetof(struct seccomp_data, nr)), 549 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1), 550 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | E2BIG), 551 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 552 }; 553 struct sock_fprog prog = { 554 .len = (unsigned short)ARRAY_SIZE(filter), 555 .filter = filter, 556 }; 557 long ret; 558 pid_t parent = getppid(); 559 560 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 561 ASSERT_EQ(0, ret); 562 563 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 564 ASSERT_EQ(0, ret); 565 566 EXPECT_EQ(parent, syscall(__NR_getppid)); 567 EXPECT_EQ(-1, read(0, NULL, 0)); 568 EXPECT_EQ(E2BIG, errno); 569 } 570 571 TEST(ERRNO_zero) 572 { 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, __NR_read, 0, 1), 577 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | 0), 578 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 579 }; 580 struct sock_fprog prog = { 581 .len = (unsigned short)ARRAY_SIZE(filter), 582 .filter = filter, 583 }; 584 long ret; 585 pid_t parent = getppid(); 586 587 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 588 ASSERT_EQ(0, ret); 589 590 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 591 ASSERT_EQ(0, ret); 592 593 EXPECT_EQ(parent, syscall(__NR_getppid)); 594 /* "errno" of 0 is ok. */ 595 EXPECT_EQ(0, read(0, NULL, 0)); 596 } 597 598 TEST(ERRNO_capped) 599 { 600 struct sock_filter filter[] = { 601 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 602 offsetof(struct seccomp_data, nr)), 603 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1), 604 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | 4096), 605 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 606 }; 607 struct sock_fprog prog = { 608 .len = (unsigned short)ARRAY_SIZE(filter), 609 .filter = filter, 610 }; 611 long ret; 612 pid_t parent = getppid(); 613 614 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 615 ASSERT_EQ(0, ret); 616 617 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog); 618 ASSERT_EQ(0, ret); 619 620 EXPECT_EQ(parent, syscall(__NR_getppid)); 621 EXPECT_EQ(-1, read(0, NULL, 0)); 622 EXPECT_EQ(4095, errno); 623 } 624 625 FIXTURE_DATA(TRAP) { 626 struct sock_fprog prog; 627 }; 628 629 FIXTURE_SETUP(TRAP) 630 { 631 struct sock_filter filter[] = { 632 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 633 offsetof(struct seccomp_data, nr)), 634 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 0, 1), 635 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRAP), 636 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 637 }; 638 639 memset(&self->prog, 0, sizeof(self->prog)); 640 self->prog.filter = malloc(sizeof(filter)); 641 ASSERT_NE(NULL, self->prog.filter); 642 memcpy(self->prog.filter, filter, sizeof(filter)); 643 self->prog.len = (unsigned short)ARRAY_SIZE(filter); 644 } 645 646 FIXTURE_TEARDOWN(TRAP) 647 { 648 if (self->prog.filter) 649 free(self->prog.filter); 650 } 651 652 TEST_F_SIGNAL(TRAP, dfl, SIGSYS) 653 { 654 long ret; 655 656 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 657 ASSERT_EQ(0, ret); 658 659 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog); 660 ASSERT_EQ(0, ret); 661 syscall(__NR_getpid); 662 } 663 664 /* Ensure that SIGSYS overrides SIG_IGN */ 665 TEST_F_SIGNAL(TRAP, ign, SIGSYS) 666 { 667 long ret; 668 669 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 670 ASSERT_EQ(0, ret); 671 672 signal(SIGSYS, SIG_IGN); 673 674 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog); 675 ASSERT_EQ(0, ret); 676 syscall(__NR_getpid); 677 } 678 679 static struct siginfo TRAP_info; 680 static volatile int TRAP_nr; 681 static void TRAP_action(int nr, siginfo_t *info, void *void_context) 682 { 683 memcpy(&TRAP_info, info, sizeof(TRAP_info)); 684 TRAP_nr = nr; 685 } 686 687 TEST_F(TRAP, handler) 688 { 689 int ret, test; 690 struct sigaction act; 691 sigset_t mask; 692 693 memset(&act, 0, sizeof(act)); 694 sigemptyset(&mask); 695 sigaddset(&mask, SIGSYS); 696 697 act.sa_sigaction = &TRAP_action; 698 act.sa_flags = SA_SIGINFO; 699 ret = sigaction(SIGSYS, &act, NULL); 700 ASSERT_EQ(0, ret) { 701 TH_LOG("sigaction failed"); 702 } 703 ret = sigprocmask(SIG_UNBLOCK, &mask, NULL); 704 ASSERT_EQ(0, ret) { 705 TH_LOG("sigprocmask failed"); 706 } 707 708 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 709 ASSERT_EQ(0, ret); 710 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog); 711 ASSERT_EQ(0, ret); 712 TRAP_nr = 0; 713 memset(&TRAP_info, 0, sizeof(TRAP_info)); 714 /* Expect the registers to be rolled back. (nr = error) may vary 715 * based on arch. */ 716 ret = syscall(__NR_getpid); 717 /* Silence gcc warning about volatile. */ 718 test = TRAP_nr; 719 EXPECT_EQ(SIGSYS, test); 720 struct local_sigsys { 721 void *_call_addr; /* calling user insn */ 722 int _syscall; /* triggering system call number */ 723 unsigned int _arch; /* AUDIT_ARCH_* of syscall */ 724 } *sigsys = (struct local_sigsys *) 725 #ifdef si_syscall 726 &(TRAP_info.si_call_addr); 727 #else 728 &TRAP_info.si_pid; 729 #endif 730 EXPECT_EQ(__NR_getpid, sigsys->_syscall); 731 /* Make sure arch is non-zero. */ 732 EXPECT_NE(0, sigsys->_arch); 733 EXPECT_NE(0, (unsigned long)sigsys->_call_addr); 734 } 735 736 FIXTURE_DATA(precedence) { 737 struct sock_fprog allow; 738 struct sock_fprog trace; 739 struct sock_fprog error; 740 struct sock_fprog trap; 741 struct sock_fprog kill; 742 }; 743 744 FIXTURE_SETUP(precedence) 745 { 746 struct sock_filter allow_insns[] = { 747 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 748 }; 749 struct sock_filter trace_insns[] = { 750 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 751 offsetof(struct seccomp_data, nr)), 752 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0), 753 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 754 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE), 755 }; 756 struct sock_filter error_insns[] = { 757 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 758 offsetof(struct seccomp_data, nr)), 759 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0), 760 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 761 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO), 762 }; 763 struct sock_filter trap_insns[] = { 764 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 765 offsetof(struct seccomp_data, nr)), 766 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0), 767 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 768 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRAP), 769 }; 770 struct sock_filter kill_insns[] = { 771 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 772 offsetof(struct seccomp_data, nr)), 773 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0), 774 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 775 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 776 }; 777 778 memset(self, 0, sizeof(*self)); 779 #define FILTER_ALLOC(_x) \ 780 self->_x.filter = malloc(sizeof(_x##_insns)); \ 781 ASSERT_NE(NULL, self->_x.filter); \ 782 memcpy(self->_x.filter, &_x##_insns, sizeof(_x##_insns)); \ 783 self->_x.len = (unsigned short)ARRAY_SIZE(_x##_insns) 784 FILTER_ALLOC(allow); 785 FILTER_ALLOC(trace); 786 FILTER_ALLOC(error); 787 FILTER_ALLOC(trap); 788 FILTER_ALLOC(kill); 789 } 790 791 FIXTURE_TEARDOWN(precedence) 792 { 793 #define FILTER_FREE(_x) if (self->_x.filter) free(self->_x.filter) 794 FILTER_FREE(allow); 795 FILTER_FREE(trace); 796 FILTER_FREE(error); 797 FILTER_FREE(trap); 798 FILTER_FREE(kill); 799 } 800 801 TEST_F(precedence, allow_ok) 802 { 803 pid_t parent, res = 0; 804 long ret; 805 806 parent = getppid(); 807 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 808 ASSERT_EQ(0, ret); 809 810 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 811 ASSERT_EQ(0, ret); 812 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 813 ASSERT_EQ(0, ret); 814 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error); 815 ASSERT_EQ(0, ret); 816 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap); 817 ASSERT_EQ(0, ret); 818 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->kill); 819 ASSERT_EQ(0, ret); 820 /* Should work just fine. */ 821 res = syscall(__NR_getppid); 822 EXPECT_EQ(parent, res); 823 } 824 825 TEST_F_SIGNAL(precedence, kill_is_highest, SIGSYS) 826 { 827 pid_t parent, res = 0; 828 long ret; 829 830 parent = getppid(); 831 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 832 ASSERT_EQ(0, ret); 833 834 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 835 ASSERT_EQ(0, ret); 836 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 837 ASSERT_EQ(0, ret); 838 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error); 839 ASSERT_EQ(0, ret); 840 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap); 841 ASSERT_EQ(0, ret); 842 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->kill); 843 ASSERT_EQ(0, ret); 844 /* Should work just fine. */ 845 res = syscall(__NR_getppid); 846 EXPECT_EQ(parent, res); 847 /* getpid() should never return. */ 848 res = syscall(__NR_getpid); 849 EXPECT_EQ(0, res); 850 } 851 852 TEST_F_SIGNAL(precedence, kill_is_highest_in_any_order, SIGSYS) 853 { 854 pid_t parent; 855 long ret; 856 857 parent = getppid(); 858 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 859 ASSERT_EQ(0, ret); 860 861 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 862 ASSERT_EQ(0, ret); 863 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->kill); 864 ASSERT_EQ(0, ret); 865 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error); 866 ASSERT_EQ(0, ret); 867 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 868 ASSERT_EQ(0, ret); 869 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap); 870 ASSERT_EQ(0, ret); 871 /* Should work just fine. */ 872 EXPECT_EQ(parent, syscall(__NR_getppid)); 873 /* getpid() should never return. */ 874 EXPECT_EQ(0, syscall(__NR_getpid)); 875 } 876 877 TEST_F_SIGNAL(precedence, trap_is_second, SIGSYS) 878 { 879 pid_t parent; 880 long ret; 881 882 parent = getppid(); 883 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 884 ASSERT_EQ(0, ret); 885 886 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 887 ASSERT_EQ(0, ret); 888 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 889 ASSERT_EQ(0, ret); 890 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error); 891 ASSERT_EQ(0, ret); 892 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap); 893 ASSERT_EQ(0, ret); 894 /* Should work just fine. */ 895 EXPECT_EQ(parent, syscall(__NR_getppid)); 896 /* getpid() should never return. */ 897 EXPECT_EQ(0, syscall(__NR_getpid)); 898 } 899 900 TEST_F_SIGNAL(precedence, trap_is_second_in_any_order, SIGSYS) 901 { 902 pid_t parent; 903 long ret; 904 905 parent = getppid(); 906 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 907 ASSERT_EQ(0, ret); 908 909 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 910 ASSERT_EQ(0, ret); 911 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap); 912 ASSERT_EQ(0, ret); 913 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 914 ASSERT_EQ(0, ret); 915 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error); 916 ASSERT_EQ(0, ret); 917 /* Should work just fine. */ 918 EXPECT_EQ(parent, syscall(__NR_getppid)); 919 /* getpid() should never return. */ 920 EXPECT_EQ(0, syscall(__NR_getpid)); 921 } 922 923 TEST_F(precedence, errno_is_third) 924 { 925 pid_t parent; 926 long ret; 927 928 parent = getppid(); 929 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 930 ASSERT_EQ(0, ret); 931 932 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 933 ASSERT_EQ(0, ret); 934 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 935 ASSERT_EQ(0, ret); 936 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error); 937 ASSERT_EQ(0, ret); 938 /* Should work just fine. */ 939 EXPECT_EQ(parent, syscall(__NR_getppid)); 940 EXPECT_EQ(0, syscall(__NR_getpid)); 941 } 942 943 TEST_F(precedence, errno_is_third_in_any_order) 944 { 945 pid_t parent; 946 long ret; 947 948 parent = getppid(); 949 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 950 ASSERT_EQ(0, ret); 951 952 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error); 953 ASSERT_EQ(0, ret); 954 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 955 ASSERT_EQ(0, ret); 956 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 957 ASSERT_EQ(0, ret); 958 /* Should work just fine. */ 959 EXPECT_EQ(parent, syscall(__NR_getppid)); 960 EXPECT_EQ(0, syscall(__NR_getpid)); 961 } 962 963 TEST_F(precedence, trace_is_fourth) 964 { 965 pid_t parent; 966 long ret; 967 968 parent = getppid(); 969 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 970 ASSERT_EQ(0, ret); 971 972 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 973 ASSERT_EQ(0, ret); 974 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 975 ASSERT_EQ(0, ret); 976 /* Should work just fine. */ 977 EXPECT_EQ(parent, syscall(__NR_getppid)); 978 /* No ptracer */ 979 EXPECT_EQ(-1, syscall(__NR_getpid)); 980 } 981 982 TEST_F(precedence, trace_is_fourth_in_any_order) 983 { 984 pid_t parent; 985 long ret; 986 987 parent = getppid(); 988 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 989 ASSERT_EQ(0, ret); 990 991 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace); 992 ASSERT_EQ(0, ret); 993 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow); 994 ASSERT_EQ(0, ret); 995 /* Should work just fine. */ 996 EXPECT_EQ(parent, syscall(__NR_getppid)); 997 /* No ptracer */ 998 EXPECT_EQ(-1, syscall(__NR_getpid)); 999 } 1000 1001 #ifndef PTRACE_O_TRACESECCOMP 1002 #define PTRACE_O_TRACESECCOMP 0x00000080 1003 #endif 1004 1005 /* Catch the Ubuntu 12.04 value error. */ 1006 #if PTRACE_EVENT_SECCOMP != 7 1007 #undef PTRACE_EVENT_SECCOMP 1008 #endif 1009 1010 #ifndef PTRACE_EVENT_SECCOMP 1011 #define PTRACE_EVENT_SECCOMP 7 1012 #endif 1013 1014 #define IS_SECCOMP_EVENT(status) ((status >> 16) == PTRACE_EVENT_SECCOMP) 1015 bool tracer_running; 1016 void tracer_stop(int sig) 1017 { 1018 tracer_running = false; 1019 } 1020 1021 typedef void tracer_func_t(struct __test_metadata *_metadata, 1022 pid_t tracee, int status, void *args); 1023 1024 void tracer(struct __test_metadata *_metadata, int fd, pid_t tracee, 1025 tracer_func_t tracer_func, void *args) 1026 { 1027 int ret = -1; 1028 struct sigaction action = { 1029 .sa_handler = tracer_stop, 1030 }; 1031 1032 /* Allow external shutdown. */ 1033 tracer_running = true; 1034 ASSERT_EQ(0, sigaction(SIGUSR1, &action, NULL)); 1035 1036 errno = 0; 1037 while (ret == -1 && errno != EINVAL) 1038 ret = ptrace(PTRACE_ATTACH, tracee, NULL, 0); 1039 ASSERT_EQ(0, ret) { 1040 kill(tracee, SIGKILL); 1041 } 1042 /* Wait for attach stop */ 1043 wait(NULL); 1044 1045 ret = ptrace(PTRACE_SETOPTIONS, tracee, NULL, PTRACE_O_TRACESECCOMP); 1046 ASSERT_EQ(0, ret) { 1047 TH_LOG("Failed to set PTRACE_O_TRACESECCOMP"); 1048 kill(tracee, SIGKILL); 1049 } 1050 ptrace(PTRACE_CONT, tracee, NULL, 0); 1051 1052 /* Unblock the tracee */ 1053 ASSERT_EQ(1, write(fd, "A", 1)); 1054 ASSERT_EQ(0, close(fd)); 1055 1056 /* Run until we're shut down. Must assert to stop execution. */ 1057 while (tracer_running) { 1058 int status; 1059 1060 if (wait(&status) != tracee) 1061 continue; 1062 if (WIFSIGNALED(status) || WIFEXITED(status)) 1063 /* Child is dead. Time to go. */ 1064 return; 1065 1066 /* Make sure this is a seccomp event. */ 1067 ASSERT_EQ(true, IS_SECCOMP_EVENT(status)); 1068 1069 tracer_func(_metadata, tracee, status, args); 1070 1071 ret = ptrace(PTRACE_CONT, tracee, NULL, NULL); 1072 ASSERT_EQ(0, ret); 1073 } 1074 /* Directly report the status of our test harness results. */ 1075 syscall(__NR_exit, _metadata->passed ? EXIT_SUCCESS : EXIT_FAILURE); 1076 } 1077 1078 /* Common tracer setup/teardown functions. */ 1079 void cont_handler(int num) 1080 { } 1081 pid_t setup_trace_fixture(struct __test_metadata *_metadata, 1082 tracer_func_t func, void *args) 1083 { 1084 char sync; 1085 int pipefd[2]; 1086 pid_t tracer_pid; 1087 pid_t tracee = getpid(); 1088 1089 /* Setup a pipe for clean synchronization. */ 1090 ASSERT_EQ(0, pipe(pipefd)); 1091 1092 /* Fork a child which we'll promote to tracer */ 1093 tracer_pid = fork(); 1094 ASSERT_LE(0, tracer_pid); 1095 signal(SIGALRM, cont_handler); 1096 if (tracer_pid == 0) { 1097 close(pipefd[0]); 1098 tracer(_metadata, pipefd[1], tracee, func, args); 1099 syscall(__NR_exit, 0); 1100 } 1101 close(pipefd[1]); 1102 prctl(PR_SET_PTRACER, tracer_pid, 0, 0, 0); 1103 read(pipefd[0], &sync, 1); 1104 close(pipefd[0]); 1105 1106 return tracer_pid; 1107 } 1108 void teardown_trace_fixture(struct __test_metadata *_metadata, 1109 pid_t tracer) 1110 { 1111 if (tracer) { 1112 int status; 1113 /* 1114 * Extract the exit code from the other process and 1115 * adopt it for ourselves in case its asserts failed. 1116 */ 1117 ASSERT_EQ(0, kill(tracer, SIGUSR1)); 1118 ASSERT_EQ(tracer, waitpid(tracer, &status, 0)); 1119 if (WEXITSTATUS(status)) 1120 _metadata->passed = 0; 1121 } 1122 } 1123 1124 /* "poke" tracer arguments and function. */ 1125 struct tracer_args_poke_t { 1126 unsigned long poke_addr; 1127 }; 1128 1129 void tracer_poke(struct __test_metadata *_metadata, pid_t tracee, int status, 1130 void *args) 1131 { 1132 int ret; 1133 unsigned long msg; 1134 struct tracer_args_poke_t *info = (struct tracer_args_poke_t *)args; 1135 1136 ret = ptrace(PTRACE_GETEVENTMSG, tracee, NULL, &msg); 1137 EXPECT_EQ(0, ret); 1138 /* If this fails, don't try to recover. */ 1139 ASSERT_EQ(0x1001, msg) { 1140 kill(tracee, SIGKILL); 1141 } 1142 /* 1143 * Poke in the message. 1144 * Registers are not touched to try to keep this relatively arch 1145 * agnostic. 1146 */ 1147 ret = ptrace(PTRACE_POKEDATA, tracee, info->poke_addr, 0x1001); 1148 EXPECT_EQ(0, ret); 1149 } 1150 1151 FIXTURE_DATA(TRACE_poke) { 1152 struct sock_fprog prog; 1153 pid_t tracer; 1154 long poked; 1155 struct tracer_args_poke_t tracer_args; 1156 }; 1157 1158 FIXTURE_SETUP(TRACE_poke) 1159 { 1160 struct sock_filter filter[] = { 1161 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 1162 offsetof(struct seccomp_data, nr)), 1163 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1), 1164 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1001), 1165 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1166 }; 1167 1168 self->poked = 0; 1169 memset(&self->prog, 0, sizeof(self->prog)); 1170 self->prog.filter = malloc(sizeof(filter)); 1171 ASSERT_NE(NULL, self->prog.filter); 1172 memcpy(self->prog.filter, filter, sizeof(filter)); 1173 self->prog.len = (unsigned short)ARRAY_SIZE(filter); 1174 1175 /* Set up tracer args. */ 1176 self->tracer_args.poke_addr = (unsigned long)&self->poked; 1177 1178 /* Launch tracer. */ 1179 self->tracer = setup_trace_fixture(_metadata, tracer_poke, 1180 &self->tracer_args); 1181 } 1182 1183 FIXTURE_TEARDOWN(TRACE_poke) 1184 { 1185 teardown_trace_fixture(_metadata, self->tracer); 1186 if (self->prog.filter) 1187 free(self->prog.filter); 1188 } 1189 1190 TEST_F(TRACE_poke, read_has_side_effects) 1191 { 1192 ssize_t ret; 1193 1194 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1195 ASSERT_EQ(0, ret); 1196 1197 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); 1198 ASSERT_EQ(0, ret); 1199 1200 EXPECT_EQ(0, self->poked); 1201 ret = read(-1, NULL, 0); 1202 EXPECT_EQ(-1, ret); 1203 EXPECT_EQ(0x1001, self->poked); 1204 } 1205 1206 TEST_F(TRACE_poke, getpid_runs_normally) 1207 { 1208 long ret; 1209 1210 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1211 ASSERT_EQ(0, ret); 1212 1213 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); 1214 ASSERT_EQ(0, ret); 1215 1216 EXPECT_EQ(0, self->poked); 1217 EXPECT_NE(0, syscall(__NR_getpid)); 1218 EXPECT_EQ(0, self->poked); 1219 } 1220 1221 #if defined(__x86_64__) 1222 # define ARCH_REGS struct user_regs_struct 1223 # define SYSCALL_NUM orig_rax 1224 # define SYSCALL_RET rax 1225 #elif defined(__i386__) 1226 # define ARCH_REGS struct user_regs_struct 1227 # define SYSCALL_NUM orig_eax 1228 # define SYSCALL_RET eax 1229 #elif defined(__arm__) 1230 # define ARCH_REGS struct pt_regs 1231 # define SYSCALL_NUM ARM_r7 1232 # define SYSCALL_RET ARM_r0 1233 #elif defined(__aarch64__) 1234 # define ARCH_REGS struct user_pt_regs 1235 # define SYSCALL_NUM regs[8] 1236 # define SYSCALL_RET regs[0] 1237 #elif defined(__powerpc__) 1238 # define ARCH_REGS struct pt_regs 1239 # define SYSCALL_NUM gpr[0] 1240 # define SYSCALL_RET gpr[3] 1241 #elif defined(__s390__) 1242 # define ARCH_REGS s390_regs 1243 # define SYSCALL_NUM gprs[2] 1244 # define SYSCALL_RET gprs[2] 1245 #else 1246 # error "Do not know how to find your architecture's registers and syscalls" 1247 #endif 1248 1249 /* Use PTRACE_GETREGS and PTRACE_SETREGS when available. This is useful for 1250 * architectures without HAVE_ARCH_TRACEHOOK (e.g. User-mode Linux). 1251 */ 1252 #if defined(__x86_64__) || defined(__i386__) 1253 #define HAVE_GETREGS 1254 #endif 1255 1256 /* Architecture-specific syscall fetching routine. */ 1257 int get_syscall(struct __test_metadata *_metadata, pid_t tracee) 1258 { 1259 ARCH_REGS regs; 1260 #ifdef HAVE_GETREGS 1261 EXPECT_EQ(0, ptrace(PTRACE_GETREGS, tracee, 0, ®s)) { 1262 TH_LOG("PTRACE_GETREGS failed"); 1263 return -1; 1264 } 1265 #else 1266 struct iovec iov; 1267 1268 iov.iov_base = ®s; 1269 iov.iov_len = sizeof(regs); 1270 EXPECT_EQ(0, ptrace(PTRACE_GETREGSET, tracee, NT_PRSTATUS, &iov)) { 1271 TH_LOG("PTRACE_GETREGSET failed"); 1272 return -1; 1273 } 1274 #endif 1275 1276 return regs.SYSCALL_NUM; 1277 } 1278 1279 /* Architecture-specific syscall changing routine. */ 1280 void change_syscall(struct __test_metadata *_metadata, 1281 pid_t tracee, int syscall) 1282 { 1283 int ret; 1284 ARCH_REGS regs; 1285 #ifdef HAVE_GETREGS 1286 ret = ptrace(PTRACE_GETREGS, tracee, 0, ®s); 1287 #else 1288 struct iovec iov; 1289 iov.iov_base = ®s; 1290 iov.iov_len = sizeof(regs); 1291 ret = ptrace(PTRACE_GETREGSET, tracee, NT_PRSTATUS, &iov); 1292 #endif 1293 EXPECT_EQ(0, ret); 1294 1295 #if defined(__x86_64__) || defined(__i386__) || defined(__powerpc__) || \ 1296 defined(__s390__) 1297 { 1298 regs.SYSCALL_NUM = syscall; 1299 } 1300 1301 #elif defined(__arm__) 1302 # ifndef PTRACE_SET_SYSCALL 1303 # define PTRACE_SET_SYSCALL 23 1304 # endif 1305 { 1306 ret = ptrace(PTRACE_SET_SYSCALL, tracee, NULL, syscall); 1307 EXPECT_EQ(0, ret); 1308 } 1309 1310 #elif defined(__aarch64__) 1311 # ifndef NT_ARM_SYSTEM_CALL 1312 # define NT_ARM_SYSTEM_CALL 0x404 1313 # endif 1314 { 1315 iov.iov_base = &syscall; 1316 iov.iov_len = sizeof(syscall); 1317 ret = ptrace(PTRACE_SETREGSET, tracee, NT_ARM_SYSTEM_CALL, 1318 &iov); 1319 EXPECT_EQ(0, ret); 1320 } 1321 1322 #else 1323 ASSERT_EQ(1, 0) { 1324 TH_LOG("How is the syscall changed on this architecture?"); 1325 } 1326 #endif 1327 1328 /* If syscall is skipped, change return value. */ 1329 if (syscall == -1) 1330 regs.SYSCALL_RET = 1; 1331 1332 #ifdef HAVE_GETREGS 1333 ret = ptrace(PTRACE_SETREGS, tracee, 0, ®s); 1334 #else 1335 iov.iov_base = ®s; 1336 iov.iov_len = sizeof(regs); 1337 ret = ptrace(PTRACE_SETREGSET, tracee, NT_PRSTATUS, &iov); 1338 #endif 1339 EXPECT_EQ(0, ret); 1340 } 1341 1342 void tracer_syscall(struct __test_metadata *_metadata, pid_t tracee, 1343 int status, void *args) 1344 { 1345 int ret; 1346 unsigned long msg; 1347 1348 /* Make sure we got the right message. */ 1349 ret = ptrace(PTRACE_GETEVENTMSG, tracee, NULL, &msg); 1350 EXPECT_EQ(0, ret); 1351 1352 /* Validate and take action on expected syscalls. */ 1353 switch (msg) { 1354 case 0x1002: 1355 /* change getpid to getppid. */ 1356 EXPECT_EQ(__NR_getpid, get_syscall(_metadata, tracee)); 1357 change_syscall(_metadata, tracee, __NR_getppid); 1358 break; 1359 case 0x1003: 1360 /* skip gettid. */ 1361 EXPECT_EQ(__NR_gettid, get_syscall(_metadata, tracee)); 1362 change_syscall(_metadata, tracee, -1); 1363 break; 1364 case 0x1004: 1365 /* do nothing (allow getppid) */ 1366 EXPECT_EQ(__NR_getppid, get_syscall(_metadata, tracee)); 1367 break; 1368 default: 1369 EXPECT_EQ(0, msg) { 1370 TH_LOG("Unknown PTRACE_GETEVENTMSG: 0x%lx", msg); 1371 kill(tracee, SIGKILL); 1372 } 1373 } 1374 1375 } 1376 1377 FIXTURE_DATA(TRACE_syscall) { 1378 struct sock_fprog prog; 1379 pid_t tracer, mytid, mypid, parent; 1380 }; 1381 1382 FIXTURE_SETUP(TRACE_syscall) 1383 { 1384 struct sock_filter filter[] = { 1385 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 1386 offsetof(struct seccomp_data, nr)), 1387 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 0, 1), 1388 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1002), 1389 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_gettid, 0, 1), 1390 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1003), 1391 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1), 1392 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1004), 1393 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1394 }; 1395 1396 memset(&self->prog, 0, sizeof(self->prog)); 1397 self->prog.filter = malloc(sizeof(filter)); 1398 ASSERT_NE(NULL, self->prog.filter); 1399 memcpy(self->prog.filter, filter, sizeof(filter)); 1400 self->prog.len = (unsigned short)ARRAY_SIZE(filter); 1401 1402 /* Prepare some testable syscall results. */ 1403 self->mytid = syscall(__NR_gettid); 1404 ASSERT_GT(self->mytid, 0); 1405 ASSERT_NE(self->mytid, 1) { 1406 TH_LOG("Running this test as init is not supported. :)"); 1407 } 1408 1409 self->mypid = getpid(); 1410 ASSERT_GT(self->mypid, 0); 1411 ASSERT_EQ(self->mytid, self->mypid); 1412 1413 self->parent = getppid(); 1414 ASSERT_GT(self->parent, 0); 1415 ASSERT_NE(self->parent, self->mypid); 1416 1417 /* Launch tracer. */ 1418 self->tracer = setup_trace_fixture(_metadata, tracer_syscall, NULL); 1419 } 1420 1421 FIXTURE_TEARDOWN(TRACE_syscall) 1422 { 1423 teardown_trace_fixture(_metadata, self->tracer); 1424 if (self->prog.filter) 1425 free(self->prog.filter); 1426 } 1427 1428 TEST_F(TRACE_syscall, syscall_allowed) 1429 { 1430 long ret; 1431 1432 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1433 ASSERT_EQ(0, ret); 1434 1435 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); 1436 ASSERT_EQ(0, ret); 1437 1438 /* getppid works as expected (no changes). */ 1439 EXPECT_EQ(self->parent, syscall(__NR_getppid)); 1440 EXPECT_NE(self->mypid, syscall(__NR_getppid)); 1441 } 1442 1443 TEST_F(TRACE_syscall, syscall_redirected) 1444 { 1445 long ret; 1446 1447 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1448 ASSERT_EQ(0, ret); 1449 1450 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); 1451 ASSERT_EQ(0, ret); 1452 1453 /* getpid has been redirected to getppid as expected. */ 1454 EXPECT_EQ(self->parent, syscall(__NR_getpid)); 1455 EXPECT_NE(self->mypid, syscall(__NR_getpid)); 1456 } 1457 1458 TEST_F(TRACE_syscall, syscall_dropped) 1459 { 1460 long ret; 1461 1462 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1463 ASSERT_EQ(0, ret); 1464 1465 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); 1466 ASSERT_EQ(0, ret); 1467 1468 /* gettid has been skipped and an altered return value stored. */ 1469 EXPECT_EQ(1, syscall(__NR_gettid)); 1470 EXPECT_NE(self->mytid, syscall(__NR_gettid)); 1471 } 1472 1473 #ifndef __NR_seccomp 1474 # if defined(__i386__) 1475 # define __NR_seccomp 354 1476 # elif defined(__x86_64__) 1477 # define __NR_seccomp 317 1478 # elif defined(__arm__) 1479 # define __NR_seccomp 383 1480 # elif defined(__aarch64__) 1481 # define __NR_seccomp 277 1482 # elif defined(__powerpc__) 1483 # define __NR_seccomp 358 1484 # elif defined(__s390__) 1485 # define __NR_seccomp 348 1486 # else 1487 # warning "seccomp syscall number unknown for this architecture" 1488 # define __NR_seccomp 0xffff 1489 # endif 1490 #endif 1491 1492 #ifndef SECCOMP_SET_MODE_STRICT 1493 #define SECCOMP_SET_MODE_STRICT 0 1494 #endif 1495 1496 #ifndef SECCOMP_SET_MODE_FILTER 1497 #define SECCOMP_SET_MODE_FILTER 1 1498 #endif 1499 1500 #ifndef SECCOMP_FILTER_FLAG_TSYNC 1501 #define SECCOMP_FILTER_FLAG_TSYNC 1 1502 #endif 1503 1504 #ifndef seccomp 1505 int seccomp(unsigned int op, unsigned int flags, void *args) 1506 { 1507 errno = 0; 1508 return syscall(__NR_seccomp, op, flags, args); 1509 } 1510 #endif 1511 1512 TEST(seccomp_syscall) 1513 { 1514 struct sock_filter filter[] = { 1515 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1516 }; 1517 struct sock_fprog prog = { 1518 .len = (unsigned short)ARRAY_SIZE(filter), 1519 .filter = filter, 1520 }; 1521 long ret; 1522 1523 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1524 ASSERT_EQ(0, ret) { 1525 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1526 } 1527 1528 /* Reject insane operation. */ 1529 ret = seccomp(-1, 0, &prog); 1530 ASSERT_NE(ENOSYS, errno) { 1531 TH_LOG("Kernel does not support seccomp syscall!"); 1532 } 1533 EXPECT_EQ(EINVAL, errno) { 1534 TH_LOG("Did not reject crazy op value!"); 1535 } 1536 1537 /* Reject strict with flags or pointer. */ 1538 ret = seccomp(SECCOMP_SET_MODE_STRICT, -1, NULL); 1539 EXPECT_EQ(EINVAL, errno) { 1540 TH_LOG("Did not reject mode strict with flags!"); 1541 } 1542 ret = seccomp(SECCOMP_SET_MODE_STRICT, 0, &prog); 1543 EXPECT_EQ(EINVAL, errno) { 1544 TH_LOG("Did not reject mode strict with uargs!"); 1545 } 1546 1547 /* Reject insane args for filter. */ 1548 ret = seccomp(SECCOMP_SET_MODE_FILTER, -1, &prog); 1549 EXPECT_EQ(EINVAL, errno) { 1550 TH_LOG("Did not reject crazy filter flags!"); 1551 } 1552 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, NULL); 1553 EXPECT_EQ(EFAULT, errno) { 1554 TH_LOG("Did not reject NULL filter!"); 1555 } 1556 1557 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog); 1558 EXPECT_EQ(0, errno) { 1559 TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER: %s", 1560 strerror(errno)); 1561 } 1562 } 1563 1564 TEST(seccomp_syscall_mode_lock) 1565 { 1566 struct sock_filter filter[] = { 1567 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1568 }; 1569 struct sock_fprog prog = { 1570 .len = (unsigned short)ARRAY_SIZE(filter), 1571 .filter = filter, 1572 }; 1573 long ret; 1574 1575 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, NULL, 0, 0); 1576 ASSERT_EQ(0, ret) { 1577 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1578 } 1579 1580 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog); 1581 ASSERT_NE(ENOSYS, errno) { 1582 TH_LOG("Kernel does not support seccomp syscall!"); 1583 } 1584 EXPECT_EQ(0, ret) { 1585 TH_LOG("Could not install filter!"); 1586 } 1587 1588 /* Make sure neither entry point will switch to strict. */ 1589 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT, 0, 0, 0); 1590 EXPECT_EQ(EINVAL, errno) { 1591 TH_LOG("Switched to mode strict!"); 1592 } 1593 1594 ret = seccomp(SECCOMP_SET_MODE_STRICT, 0, NULL); 1595 EXPECT_EQ(EINVAL, errno) { 1596 TH_LOG("Switched to mode strict!"); 1597 } 1598 } 1599 1600 TEST(TSYNC_first) 1601 { 1602 struct sock_filter filter[] = { 1603 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1604 }; 1605 struct sock_fprog prog = { 1606 .len = (unsigned short)ARRAY_SIZE(filter), 1607 .filter = filter, 1608 }; 1609 long ret; 1610 1611 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, NULL, 0, 0); 1612 ASSERT_EQ(0, ret) { 1613 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1614 } 1615 1616 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC, 1617 &prog); 1618 ASSERT_NE(ENOSYS, errno) { 1619 TH_LOG("Kernel does not support seccomp syscall!"); 1620 } 1621 EXPECT_EQ(0, ret) { 1622 TH_LOG("Could not install initial filter with TSYNC!"); 1623 } 1624 } 1625 1626 #define TSYNC_SIBLINGS 2 1627 struct tsync_sibling { 1628 pthread_t tid; 1629 pid_t system_tid; 1630 sem_t *started; 1631 pthread_cond_t *cond; 1632 pthread_mutex_t *mutex; 1633 int diverge; 1634 int num_waits; 1635 struct sock_fprog *prog; 1636 struct __test_metadata *metadata; 1637 }; 1638 1639 FIXTURE_DATA(TSYNC) { 1640 struct sock_fprog root_prog, apply_prog; 1641 struct tsync_sibling sibling[TSYNC_SIBLINGS]; 1642 sem_t started; 1643 pthread_cond_t cond; 1644 pthread_mutex_t mutex; 1645 int sibling_count; 1646 }; 1647 1648 FIXTURE_SETUP(TSYNC) 1649 { 1650 struct sock_filter root_filter[] = { 1651 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1652 }; 1653 struct sock_filter apply_filter[] = { 1654 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 1655 offsetof(struct seccomp_data, nr)), 1656 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1), 1657 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 1658 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1659 }; 1660 1661 memset(&self->root_prog, 0, sizeof(self->root_prog)); 1662 memset(&self->apply_prog, 0, sizeof(self->apply_prog)); 1663 memset(&self->sibling, 0, sizeof(self->sibling)); 1664 self->root_prog.filter = malloc(sizeof(root_filter)); 1665 ASSERT_NE(NULL, self->root_prog.filter); 1666 memcpy(self->root_prog.filter, &root_filter, sizeof(root_filter)); 1667 self->root_prog.len = (unsigned short)ARRAY_SIZE(root_filter); 1668 1669 self->apply_prog.filter = malloc(sizeof(apply_filter)); 1670 ASSERT_NE(NULL, self->apply_prog.filter); 1671 memcpy(self->apply_prog.filter, &apply_filter, sizeof(apply_filter)); 1672 self->apply_prog.len = (unsigned short)ARRAY_SIZE(apply_filter); 1673 1674 self->sibling_count = 0; 1675 pthread_mutex_init(&self->mutex, NULL); 1676 pthread_cond_init(&self->cond, NULL); 1677 sem_init(&self->started, 0, 0); 1678 self->sibling[0].tid = 0; 1679 self->sibling[0].cond = &self->cond; 1680 self->sibling[0].started = &self->started; 1681 self->sibling[0].mutex = &self->mutex; 1682 self->sibling[0].diverge = 0; 1683 self->sibling[0].num_waits = 1; 1684 self->sibling[0].prog = &self->root_prog; 1685 self->sibling[0].metadata = _metadata; 1686 self->sibling[1].tid = 0; 1687 self->sibling[1].cond = &self->cond; 1688 self->sibling[1].started = &self->started; 1689 self->sibling[1].mutex = &self->mutex; 1690 self->sibling[1].diverge = 0; 1691 self->sibling[1].prog = &self->root_prog; 1692 self->sibling[1].num_waits = 1; 1693 self->sibling[1].metadata = _metadata; 1694 } 1695 1696 FIXTURE_TEARDOWN(TSYNC) 1697 { 1698 int sib = 0; 1699 1700 if (self->root_prog.filter) 1701 free(self->root_prog.filter); 1702 if (self->apply_prog.filter) 1703 free(self->apply_prog.filter); 1704 1705 for ( ; sib < self->sibling_count; ++sib) { 1706 struct tsync_sibling *s = &self->sibling[sib]; 1707 void *status; 1708 1709 if (!s->tid) 1710 continue; 1711 if (pthread_kill(s->tid, 0)) { 1712 pthread_cancel(s->tid); 1713 pthread_join(s->tid, &status); 1714 } 1715 } 1716 pthread_mutex_destroy(&self->mutex); 1717 pthread_cond_destroy(&self->cond); 1718 sem_destroy(&self->started); 1719 } 1720 1721 void *tsync_sibling(void *data) 1722 { 1723 long ret = 0; 1724 struct tsync_sibling *me = data; 1725 1726 me->system_tid = syscall(__NR_gettid); 1727 1728 pthread_mutex_lock(me->mutex); 1729 if (me->diverge) { 1730 /* Just re-apply the root prog to fork the tree */ 1731 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, 1732 me->prog, 0, 0); 1733 } 1734 sem_post(me->started); 1735 /* Return outside of started so parent notices failures. */ 1736 if (ret) { 1737 pthread_mutex_unlock(me->mutex); 1738 return (void *)SIBLING_EXIT_FAILURE; 1739 } 1740 do { 1741 pthread_cond_wait(me->cond, me->mutex); 1742 me->num_waits = me->num_waits - 1; 1743 } while (me->num_waits); 1744 pthread_mutex_unlock(me->mutex); 1745 1746 ret = prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0); 1747 if (!ret) 1748 return (void *)SIBLING_EXIT_NEWPRIVS; 1749 read(0, NULL, 0); 1750 return (void *)SIBLING_EXIT_UNKILLED; 1751 } 1752 1753 void tsync_start_sibling(struct tsync_sibling *sibling) 1754 { 1755 pthread_create(&sibling->tid, NULL, tsync_sibling, (void *)sibling); 1756 } 1757 1758 TEST_F(TSYNC, siblings_fail_prctl) 1759 { 1760 long ret; 1761 void *status; 1762 struct sock_filter filter[] = { 1763 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 1764 offsetof(struct seccomp_data, nr)), 1765 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_prctl, 0, 1), 1766 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | EINVAL), 1767 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1768 }; 1769 struct sock_fprog prog = { 1770 .len = (unsigned short)ARRAY_SIZE(filter), 1771 .filter = filter, 1772 }; 1773 1774 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 1775 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1776 } 1777 1778 /* Check prctl failure detection by requesting sib 0 diverge. */ 1779 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog); 1780 ASSERT_NE(ENOSYS, errno) { 1781 TH_LOG("Kernel does not support seccomp syscall!"); 1782 } 1783 ASSERT_EQ(0, ret) { 1784 TH_LOG("setting filter failed"); 1785 } 1786 1787 self->sibling[0].diverge = 1; 1788 tsync_start_sibling(&self->sibling[0]); 1789 tsync_start_sibling(&self->sibling[1]); 1790 1791 while (self->sibling_count < TSYNC_SIBLINGS) { 1792 sem_wait(&self->started); 1793 self->sibling_count++; 1794 } 1795 1796 /* Signal the threads to clean up*/ 1797 pthread_mutex_lock(&self->mutex); 1798 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 1799 TH_LOG("cond broadcast non-zero"); 1800 } 1801 pthread_mutex_unlock(&self->mutex); 1802 1803 /* Ensure diverging sibling failed to call prctl. */ 1804 pthread_join(self->sibling[0].tid, &status); 1805 EXPECT_EQ(SIBLING_EXIT_FAILURE, (long)status); 1806 pthread_join(self->sibling[1].tid, &status); 1807 EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status); 1808 } 1809 1810 TEST_F(TSYNC, two_siblings_with_ancestor) 1811 { 1812 long ret; 1813 void *status; 1814 1815 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 1816 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1817 } 1818 1819 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &self->root_prog); 1820 ASSERT_NE(ENOSYS, errno) { 1821 TH_LOG("Kernel does not support seccomp syscall!"); 1822 } 1823 ASSERT_EQ(0, ret) { 1824 TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER!"); 1825 } 1826 tsync_start_sibling(&self->sibling[0]); 1827 tsync_start_sibling(&self->sibling[1]); 1828 1829 while (self->sibling_count < TSYNC_SIBLINGS) { 1830 sem_wait(&self->started); 1831 self->sibling_count++; 1832 } 1833 1834 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC, 1835 &self->apply_prog); 1836 ASSERT_EQ(0, ret) { 1837 TH_LOG("Could install filter on all threads!"); 1838 } 1839 /* Tell the siblings to test the policy */ 1840 pthread_mutex_lock(&self->mutex); 1841 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 1842 TH_LOG("cond broadcast non-zero"); 1843 } 1844 pthread_mutex_unlock(&self->mutex); 1845 /* Ensure they are both killed and don't exit cleanly. */ 1846 pthread_join(self->sibling[0].tid, &status); 1847 EXPECT_EQ(0x0, (long)status); 1848 pthread_join(self->sibling[1].tid, &status); 1849 EXPECT_EQ(0x0, (long)status); 1850 } 1851 1852 TEST_F(TSYNC, two_sibling_want_nnp) 1853 { 1854 void *status; 1855 1856 /* start siblings before any prctl() operations */ 1857 tsync_start_sibling(&self->sibling[0]); 1858 tsync_start_sibling(&self->sibling[1]); 1859 while (self->sibling_count < TSYNC_SIBLINGS) { 1860 sem_wait(&self->started); 1861 self->sibling_count++; 1862 } 1863 1864 /* Tell the siblings to test no policy */ 1865 pthread_mutex_lock(&self->mutex); 1866 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 1867 TH_LOG("cond broadcast non-zero"); 1868 } 1869 pthread_mutex_unlock(&self->mutex); 1870 1871 /* Ensure they are both upset about lacking nnp. */ 1872 pthread_join(self->sibling[0].tid, &status); 1873 EXPECT_EQ(SIBLING_EXIT_NEWPRIVS, (long)status); 1874 pthread_join(self->sibling[1].tid, &status); 1875 EXPECT_EQ(SIBLING_EXIT_NEWPRIVS, (long)status); 1876 } 1877 1878 TEST_F(TSYNC, two_siblings_with_no_filter) 1879 { 1880 long ret; 1881 void *status; 1882 1883 /* start siblings before any prctl() operations */ 1884 tsync_start_sibling(&self->sibling[0]); 1885 tsync_start_sibling(&self->sibling[1]); 1886 while (self->sibling_count < TSYNC_SIBLINGS) { 1887 sem_wait(&self->started); 1888 self->sibling_count++; 1889 } 1890 1891 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 1892 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1893 } 1894 1895 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC, 1896 &self->apply_prog); 1897 ASSERT_NE(ENOSYS, errno) { 1898 TH_LOG("Kernel does not support seccomp syscall!"); 1899 } 1900 ASSERT_EQ(0, ret) { 1901 TH_LOG("Could install filter on all threads!"); 1902 } 1903 1904 /* Tell the siblings to test the policy */ 1905 pthread_mutex_lock(&self->mutex); 1906 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 1907 TH_LOG("cond broadcast non-zero"); 1908 } 1909 pthread_mutex_unlock(&self->mutex); 1910 1911 /* Ensure they are both killed and don't exit cleanly. */ 1912 pthread_join(self->sibling[0].tid, &status); 1913 EXPECT_EQ(0x0, (long)status); 1914 pthread_join(self->sibling[1].tid, &status); 1915 EXPECT_EQ(0x0, (long)status); 1916 } 1917 1918 TEST_F(TSYNC, two_siblings_with_one_divergence) 1919 { 1920 long ret; 1921 void *status; 1922 1923 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 1924 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1925 } 1926 1927 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &self->root_prog); 1928 ASSERT_NE(ENOSYS, errno) { 1929 TH_LOG("Kernel does not support seccomp syscall!"); 1930 } 1931 ASSERT_EQ(0, ret) { 1932 TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER!"); 1933 } 1934 self->sibling[0].diverge = 1; 1935 tsync_start_sibling(&self->sibling[0]); 1936 tsync_start_sibling(&self->sibling[1]); 1937 1938 while (self->sibling_count < TSYNC_SIBLINGS) { 1939 sem_wait(&self->started); 1940 self->sibling_count++; 1941 } 1942 1943 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC, 1944 &self->apply_prog); 1945 ASSERT_EQ(self->sibling[0].system_tid, ret) { 1946 TH_LOG("Did not fail on diverged sibling."); 1947 } 1948 1949 /* Wake the threads */ 1950 pthread_mutex_lock(&self->mutex); 1951 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 1952 TH_LOG("cond broadcast non-zero"); 1953 } 1954 pthread_mutex_unlock(&self->mutex); 1955 1956 /* Ensure they are both unkilled. */ 1957 pthread_join(self->sibling[0].tid, &status); 1958 EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status); 1959 pthread_join(self->sibling[1].tid, &status); 1960 EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status); 1961 } 1962 1963 TEST_F(TSYNC, two_siblings_not_under_filter) 1964 { 1965 long ret, sib; 1966 void *status; 1967 1968 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 1969 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1970 } 1971 1972 /* 1973 * Sibling 0 will have its own seccomp policy 1974 * and Sibling 1 will not be under seccomp at 1975 * all. Sibling 1 will enter seccomp and 0 1976 * will cause failure. 1977 */ 1978 self->sibling[0].diverge = 1; 1979 tsync_start_sibling(&self->sibling[0]); 1980 tsync_start_sibling(&self->sibling[1]); 1981 1982 while (self->sibling_count < TSYNC_SIBLINGS) { 1983 sem_wait(&self->started); 1984 self->sibling_count++; 1985 } 1986 1987 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &self->root_prog); 1988 ASSERT_NE(ENOSYS, errno) { 1989 TH_LOG("Kernel does not support seccomp syscall!"); 1990 } 1991 ASSERT_EQ(0, ret) { 1992 TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER!"); 1993 } 1994 1995 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC, 1996 &self->apply_prog); 1997 ASSERT_EQ(ret, self->sibling[0].system_tid) { 1998 TH_LOG("Did not fail on diverged sibling."); 1999 } 2000 sib = 1; 2001 if (ret == self->sibling[0].system_tid) 2002 sib = 0; 2003 2004 pthread_mutex_lock(&self->mutex); 2005 2006 /* Increment the other siblings num_waits so we can clean up 2007 * the one we just saw. 2008 */ 2009 self->sibling[!sib].num_waits += 1; 2010 2011 /* Signal the thread to clean up*/ 2012 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 2013 TH_LOG("cond broadcast non-zero"); 2014 } 2015 pthread_mutex_unlock(&self->mutex); 2016 pthread_join(self->sibling[sib].tid, &status); 2017 EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status); 2018 /* Poll for actual task death. pthread_join doesn't guarantee it. */ 2019 while (!kill(self->sibling[sib].system_tid, 0)) 2020 sleep(0.1); 2021 /* Switch to the remaining sibling */ 2022 sib = !sib; 2023 2024 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC, 2025 &self->apply_prog); 2026 ASSERT_EQ(0, ret) { 2027 TH_LOG("Expected the remaining sibling to sync"); 2028 }; 2029 2030 pthread_mutex_lock(&self->mutex); 2031 2032 /* If remaining sibling didn't have a chance to wake up during 2033 * the first broadcast, manually reduce the num_waits now. 2034 */ 2035 if (self->sibling[sib].num_waits > 1) 2036 self->sibling[sib].num_waits = 1; 2037 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 2038 TH_LOG("cond broadcast non-zero"); 2039 } 2040 pthread_mutex_unlock(&self->mutex); 2041 pthread_join(self->sibling[sib].tid, &status); 2042 EXPECT_EQ(0, (long)status); 2043 /* Poll for actual task death. pthread_join doesn't guarantee it. */ 2044 while (!kill(self->sibling[sib].system_tid, 0)) 2045 sleep(0.1); 2046 2047 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC, 2048 &self->apply_prog); 2049 ASSERT_EQ(0, ret); /* just us chickens */ 2050 } 2051 2052 /* Make sure restarted syscalls are seen directly as "restart_syscall". */ 2053 TEST(syscall_restart) 2054 { 2055 long ret; 2056 unsigned long msg; 2057 pid_t child_pid; 2058 int pipefd[2]; 2059 int status; 2060 siginfo_t info = { }; 2061 struct sock_filter filter[] = { 2062 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 2063 offsetof(struct seccomp_data, nr)), 2064 2065 #ifdef __NR_sigreturn 2066 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_sigreturn, 6, 0), 2067 #endif 2068 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 5, 0), 2069 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_exit, 4, 0), 2070 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_rt_sigreturn, 3, 0), 2071 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_nanosleep, 4, 0), 2072 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_restart_syscall, 4, 0), 2073 2074 /* Allow __NR_write for easy logging. */ 2075 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_write, 0, 1), 2076 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 2077 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 2078 /* The nanosleep jump target. */ 2079 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE|0x100), 2080 /* The restart_syscall jump target. */ 2081 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE|0x200), 2082 }; 2083 struct sock_fprog prog = { 2084 .len = (unsigned short)ARRAY_SIZE(filter), 2085 .filter = filter, 2086 }; 2087 #if defined(__arm__) 2088 struct utsname utsbuf; 2089 #endif 2090 2091 ASSERT_EQ(0, pipe(pipefd)); 2092 2093 child_pid = fork(); 2094 ASSERT_LE(0, child_pid); 2095 if (child_pid == 0) { 2096 /* Child uses EXPECT not ASSERT to deliver status correctly. */ 2097 char buf = ' '; 2098 struct timespec timeout = { }; 2099 2100 /* Attach parent as tracer and stop. */ 2101 EXPECT_EQ(0, ptrace(PTRACE_TRACEME)); 2102 EXPECT_EQ(0, raise(SIGSTOP)); 2103 2104 EXPECT_EQ(0, close(pipefd[1])); 2105 2106 EXPECT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 2107 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 2108 } 2109 2110 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 2111 EXPECT_EQ(0, ret) { 2112 TH_LOG("Failed to install filter!"); 2113 } 2114 2115 EXPECT_EQ(1, read(pipefd[0], &buf, 1)) { 2116 TH_LOG("Failed to read() sync from parent"); 2117 } 2118 EXPECT_EQ('.', buf) { 2119 TH_LOG("Failed to get sync data from read()"); 2120 } 2121 2122 /* Start nanosleep to be interrupted. */ 2123 timeout.tv_sec = 1; 2124 errno = 0; 2125 EXPECT_EQ(0, nanosleep(&timeout, NULL)) { 2126 TH_LOG("Call to nanosleep() failed (errno %d)", errno); 2127 } 2128 2129 /* Read final sync from parent. */ 2130 EXPECT_EQ(1, read(pipefd[0], &buf, 1)) { 2131 TH_LOG("Failed final read() from parent"); 2132 } 2133 EXPECT_EQ('!', buf) { 2134 TH_LOG("Failed to get final data from read()"); 2135 } 2136 2137 /* Directly report the status of our test harness results. */ 2138 syscall(__NR_exit, _metadata->passed ? EXIT_SUCCESS 2139 : EXIT_FAILURE); 2140 } 2141 EXPECT_EQ(0, close(pipefd[0])); 2142 2143 /* Attach to child, setup options, and release. */ 2144 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2145 ASSERT_EQ(true, WIFSTOPPED(status)); 2146 ASSERT_EQ(0, ptrace(PTRACE_SETOPTIONS, child_pid, NULL, 2147 PTRACE_O_TRACESECCOMP)); 2148 ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0)); 2149 ASSERT_EQ(1, write(pipefd[1], ".", 1)); 2150 2151 /* Wait for nanosleep() to start. */ 2152 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2153 ASSERT_EQ(true, WIFSTOPPED(status)); 2154 ASSERT_EQ(SIGTRAP, WSTOPSIG(status)); 2155 ASSERT_EQ(PTRACE_EVENT_SECCOMP, (status >> 16)); 2156 ASSERT_EQ(0, ptrace(PTRACE_GETEVENTMSG, child_pid, NULL, &msg)); 2157 ASSERT_EQ(0x100, msg); 2158 EXPECT_EQ(__NR_nanosleep, get_syscall(_metadata, child_pid)); 2159 2160 /* Might as well check siginfo for sanity while we're here. */ 2161 ASSERT_EQ(0, ptrace(PTRACE_GETSIGINFO, child_pid, NULL, &info)); 2162 ASSERT_EQ(SIGTRAP, info.si_signo); 2163 ASSERT_EQ(SIGTRAP | (PTRACE_EVENT_SECCOMP << 8), info.si_code); 2164 EXPECT_EQ(0, info.si_errno); 2165 EXPECT_EQ(getuid(), info.si_uid); 2166 /* Verify signal delivery came from child (seccomp-triggered). */ 2167 EXPECT_EQ(child_pid, info.si_pid); 2168 2169 /* Interrupt nanosleep with SIGSTOP (which we'll need to handle). */ 2170 ASSERT_EQ(0, kill(child_pid, SIGSTOP)); 2171 ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0)); 2172 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2173 ASSERT_EQ(true, WIFSTOPPED(status)); 2174 ASSERT_EQ(SIGSTOP, WSTOPSIG(status)); 2175 /* Verify signal delivery came from parent now. */ 2176 ASSERT_EQ(0, ptrace(PTRACE_GETSIGINFO, child_pid, NULL, &info)); 2177 EXPECT_EQ(getpid(), info.si_pid); 2178 2179 /* Restart nanosleep with SIGCONT, which triggers restart_syscall. */ 2180 ASSERT_EQ(0, kill(child_pid, SIGCONT)); 2181 ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0)); 2182 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2183 ASSERT_EQ(true, WIFSTOPPED(status)); 2184 ASSERT_EQ(SIGCONT, WSTOPSIG(status)); 2185 ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0)); 2186 2187 /* Wait for restart_syscall() to start. */ 2188 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2189 ASSERT_EQ(true, WIFSTOPPED(status)); 2190 ASSERT_EQ(SIGTRAP, WSTOPSIG(status)); 2191 ASSERT_EQ(PTRACE_EVENT_SECCOMP, (status >> 16)); 2192 ASSERT_EQ(0, ptrace(PTRACE_GETEVENTMSG, child_pid, NULL, &msg)); 2193 2194 ASSERT_EQ(0x200, msg); 2195 ret = get_syscall(_metadata, child_pid); 2196 #if defined(__arm__) 2197 /* 2198 * FIXME: 2199 * - native ARM registers do NOT expose true syscall. 2200 * - compat ARM registers on ARM64 DO expose true syscall. 2201 */ 2202 ASSERT_EQ(0, uname(&utsbuf)); 2203 if (strncmp(utsbuf.machine, "arm", 3) == 0) { 2204 EXPECT_EQ(__NR_nanosleep, ret); 2205 } else 2206 #endif 2207 { 2208 EXPECT_EQ(__NR_restart_syscall, ret); 2209 } 2210 2211 /* Write again to end test. */ 2212 ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0)); 2213 ASSERT_EQ(1, write(pipefd[1], "!", 1)); 2214 EXPECT_EQ(0, close(pipefd[1])); 2215 2216 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2217 if (WIFSIGNALED(status) || WEXITSTATUS(status)) 2218 _metadata->passed = 0; 2219 } 2220 2221 /* 2222 * TODO: 2223 * - add microbenchmarks 2224 * - expand NNP testing 2225 * - better arch-specific TRACE and TRAP handlers. 2226 * - endianness checking when appropriate 2227 * - 64-bit arg prodding 2228 * - arch value testing (x86 modes especially) 2229 * - ... 2230 */ 2231 2232 TEST_HARNESS_MAIN 2233