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 /* Architecture-specific syscall fetching routine. */ 1250 int get_syscall(struct __test_metadata *_metadata, pid_t tracee) 1251 { 1252 struct iovec iov; 1253 ARCH_REGS regs; 1254 1255 iov.iov_base = ®s; 1256 iov.iov_len = sizeof(regs); 1257 EXPECT_EQ(0, ptrace(PTRACE_GETREGSET, tracee, NT_PRSTATUS, &iov)) { 1258 TH_LOG("PTRACE_GETREGSET failed"); 1259 return -1; 1260 } 1261 1262 return regs.SYSCALL_NUM; 1263 } 1264 1265 /* Architecture-specific syscall changing routine. */ 1266 void change_syscall(struct __test_metadata *_metadata, 1267 pid_t tracee, int syscall) 1268 { 1269 struct iovec iov; 1270 int ret; 1271 ARCH_REGS regs; 1272 1273 iov.iov_base = ®s; 1274 iov.iov_len = sizeof(regs); 1275 ret = ptrace(PTRACE_GETREGSET, tracee, NT_PRSTATUS, &iov); 1276 EXPECT_EQ(0, ret); 1277 1278 #if defined(__x86_64__) || defined(__i386__) || defined(__powerpc__) || \ 1279 defined(__s390__) 1280 { 1281 regs.SYSCALL_NUM = syscall; 1282 } 1283 1284 #elif defined(__arm__) 1285 # ifndef PTRACE_SET_SYSCALL 1286 # define PTRACE_SET_SYSCALL 23 1287 # endif 1288 { 1289 ret = ptrace(PTRACE_SET_SYSCALL, tracee, NULL, syscall); 1290 EXPECT_EQ(0, ret); 1291 } 1292 1293 #elif defined(__aarch64__) 1294 # ifndef NT_ARM_SYSTEM_CALL 1295 # define NT_ARM_SYSTEM_CALL 0x404 1296 # endif 1297 { 1298 iov.iov_base = &syscall; 1299 iov.iov_len = sizeof(syscall); 1300 ret = ptrace(PTRACE_SETREGSET, tracee, NT_ARM_SYSTEM_CALL, 1301 &iov); 1302 EXPECT_EQ(0, ret); 1303 } 1304 1305 #else 1306 ASSERT_EQ(1, 0) { 1307 TH_LOG("How is the syscall changed on this architecture?"); 1308 } 1309 #endif 1310 1311 /* If syscall is skipped, change return value. */ 1312 if (syscall == -1) 1313 regs.SYSCALL_RET = 1; 1314 1315 iov.iov_base = ®s; 1316 iov.iov_len = sizeof(regs); 1317 ret = ptrace(PTRACE_SETREGSET, tracee, NT_PRSTATUS, &iov); 1318 EXPECT_EQ(0, ret); 1319 } 1320 1321 void tracer_syscall(struct __test_metadata *_metadata, pid_t tracee, 1322 int status, void *args) 1323 { 1324 int ret; 1325 unsigned long msg; 1326 1327 /* Make sure we got the right message. */ 1328 ret = ptrace(PTRACE_GETEVENTMSG, tracee, NULL, &msg); 1329 EXPECT_EQ(0, ret); 1330 1331 /* Validate and take action on expected syscalls. */ 1332 switch (msg) { 1333 case 0x1002: 1334 /* change getpid to getppid. */ 1335 EXPECT_EQ(__NR_getpid, get_syscall(_metadata, tracee)); 1336 change_syscall(_metadata, tracee, __NR_getppid); 1337 break; 1338 case 0x1003: 1339 /* skip gettid. */ 1340 EXPECT_EQ(__NR_gettid, get_syscall(_metadata, tracee)); 1341 change_syscall(_metadata, tracee, -1); 1342 break; 1343 case 0x1004: 1344 /* do nothing (allow getppid) */ 1345 EXPECT_EQ(__NR_getppid, get_syscall(_metadata, tracee)); 1346 break; 1347 default: 1348 EXPECT_EQ(0, msg) { 1349 TH_LOG("Unknown PTRACE_GETEVENTMSG: 0x%lx", msg); 1350 kill(tracee, SIGKILL); 1351 } 1352 } 1353 1354 } 1355 1356 FIXTURE_DATA(TRACE_syscall) { 1357 struct sock_fprog prog; 1358 pid_t tracer, mytid, mypid, parent; 1359 }; 1360 1361 FIXTURE_SETUP(TRACE_syscall) 1362 { 1363 struct sock_filter filter[] = { 1364 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 1365 offsetof(struct seccomp_data, nr)), 1366 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 0, 1), 1367 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1002), 1368 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_gettid, 0, 1), 1369 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1003), 1370 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1), 1371 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1004), 1372 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1373 }; 1374 1375 memset(&self->prog, 0, sizeof(self->prog)); 1376 self->prog.filter = malloc(sizeof(filter)); 1377 ASSERT_NE(NULL, self->prog.filter); 1378 memcpy(self->prog.filter, filter, sizeof(filter)); 1379 self->prog.len = (unsigned short)ARRAY_SIZE(filter); 1380 1381 /* Prepare some testable syscall results. */ 1382 self->mytid = syscall(__NR_gettid); 1383 ASSERT_GT(self->mytid, 0); 1384 ASSERT_NE(self->mytid, 1) { 1385 TH_LOG("Running this test as init is not supported. :)"); 1386 } 1387 1388 self->mypid = getpid(); 1389 ASSERT_GT(self->mypid, 0); 1390 ASSERT_EQ(self->mytid, self->mypid); 1391 1392 self->parent = getppid(); 1393 ASSERT_GT(self->parent, 0); 1394 ASSERT_NE(self->parent, self->mypid); 1395 1396 /* Launch tracer. */ 1397 self->tracer = setup_trace_fixture(_metadata, tracer_syscall, NULL); 1398 } 1399 1400 FIXTURE_TEARDOWN(TRACE_syscall) 1401 { 1402 teardown_trace_fixture(_metadata, self->tracer); 1403 if (self->prog.filter) 1404 free(self->prog.filter); 1405 } 1406 1407 TEST_F(TRACE_syscall, syscall_allowed) 1408 { 1409 long ret; 1410 1411 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1412 ASSERT_EQ(0, ret); 1413 1414 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); 1415 ASSERT_EQ(0, ret); 1416 1417 /* getppid works as expected (no changes). */ 1418 EXPECT_EQ(self->parent, syscall(__NR_getppid)); 1419 EXPECT_NE(self->mypid, syscall(__NR_getppid)); 1420 } 1421 1422 TEST_F(TRACE_syscall, syscall_redirected) 1423 { 1424 long ret; 1425 1426 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1427 ASSERT_EQ(0, ret); 1428 1429 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); 1430 ASSERT_EQ(0, ret); 1431 1432 /* getpid has been redirected to getppid as expected. */ 1433 EXPECT_EQ(self->parent, syscall(__NR_getpid)); 1434 EXPECT_NE(self->mypid, syscall(__NR_getpid)); 1435 } 1436 1437 TEST_F(TRACE_syscall, syscall_dropped) 1438 { 1439 long ret; 1440 1441 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1442 ASSERT_EQ(0, ret); 1443 1444 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); 1445 ASSERT_EQ(0, ret); 1446 1447 /* gettid has been skipped and an altered return value stored. */ 1448 EXPECT_EQ(1, syscall(__NR_gettid)); 1449 EXPECT_NE(self->mytid, syscall(__NR_gettid)); 1450 } 1451 1452 #ifndef __NR_seccomp 1453 # if defined(__i386__) 1454 # define __NR_seccomp 354 1455 # elif defined(__x86_64__) 1456 # define __NR_seccomp 317 1457 # elif defined(__arm__) 1458 # define __NR_seccomp 383 1459 # elif defined(__aarch64__) 1460 # define __NR_seccomp 277 1461 # elif defined(__powerpc__) 1462 # define __NR_seccomp 358 1463 # elif defined(__s390__) 1464 # define __NR_seccomp 348 1465 # else 1466 # warning "seccomp syscall number unknown for this architecture" 1467 # define __NR_seccomp 0xffff 1468 # endif 1469 #endif 1470 1471 #ifndef SECCOMP_SET_MODE_STRICT 1472 #define SECCOMP_SET_MODE_STRICT 0 1473 #endif 1474 1475 #ifndef SECCOMP_SET_MODE_FILTER 1476 #define SECCOMP_SET_MODE_FILTER 1 1477 #endif 1478 1479 #ifndef SECCOMP_FLAG_FILTER_TSYNC 1480 #define SECCOMP_FLAG_FILTER_TSYNC 1 1481 #endif 1482 1483 #ifndef seccomp 1484 int seccomp(unsigned int op, unsigned int flags, struct sock_fprog *filter) 1485 { 1486 errno = 0; 1487 return syscall(__NR_seccomp, op, flags, filter); 1488 } 1489 #endif 1490 1491 TEST(seccomp_syscall) 1492 { 1493 struct sock_filter filter[] = { 1494 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1495 }; 1496 struct sock_fprog prog = { 1497 .len = (unsigned short)ARRAY_SIZE(filter), 1498 .filter = filter, 1499 }; 1500 long ret; 1501 1502 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); 1503 ASSERT_EQ(0, ret) { 1504 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1505 } 1506 1507 /* Reject insane operation. */ 1508 ret = seccomp(-1, 0, &prog); 1509 ASSERT_NE(ENOSYS, errno) { 1510 TH_LOG("Kernel does not support seccomp syscall!"); 1511 } 1512 EXPECT_EQ(EINVAL, errno) { 1513 TH_LOG("Did not reject crazy op value!"); 1514 } 1515 1516 /* Reject strict with flags or pointer. */ 1517 ret = seccomp(SECCOMP_SET_MODE_STRICT, -1, NULL); 1518 EXPECT_EQ(EINVAL, errno) { 1519 TH_LOG("Did not reject mode strict with flags!"); 1520 } 1521 ret = seccomp(SECCOMP_SET_MODE_STRICT, 0, &prog); 1522 EXPECT_EQ(EINVAL, errno) { 1523 TH_LOG("Did not reject mode strict with uargs!"); 1524 } 1525 1526 /* Reject insane args for filter. */ 1527 ret = seccomp(SECCOMP_SET_MODE_FILTER, -1, &prog); 1528 EXPECT_EQ(EINVAL, errno) { 1529 TH_LOG("Did not reject crazy filter flags!"); 1530 } 1531 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, NULL); 1532 EXPECT_EQ(EFAULT, errno) { 1533 TH_LOG("Did not reject NULL filter!"); 1534 } 1535 1536 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog); 1537 EXPECT_EQ(0, errno) { 1538 TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER: %s", 1539 strerror(errno)); 1540 } 1541 } 1542 1543 TEST(seccomp_syscall_mode_lock) 1544 { 1545 struct sock_filter filter[] = { 1546 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1547 }; 1548 struct sock_fprog prog = { 1549 .len = (unsigned short)ARRAY_SIZE(filter), 1550 .filter = filter, 1551 }; 1552 long ret; 1553 1554 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, NULL, 0, 0); 1555 ASSERT_EQ(0, ret) { 1556 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1557 } 1558 1559 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog); 1560 ASSERT_NE(ENOSYS, errno) { 1561 TH_LOG("Kernel does not support seccomp syscall!"); 1562 } 1563 EXPECT_EQ(0, ret) { 1564 TH_LOG("Could not install filter!"); 1565 } 1566 1567 /* Make sure neither entry point will switch to strict. */ 1568 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT, 0, 0, 0); 1569 EXPECT_EQ(EINVAL, errno) { 1570 TH_LOG("Switched to mode strict!"); 1571 } 1572 1573 ret = seccomp(SECCOMP_SET_MODE_STRICT, 0, NULL); 1574 EXPECT_EQ(EINVAL, errno) { 1575 TH_LOG("Switched to mode strict!"); 1576 } 1577 } 1578 1579 TEST(TSYNC_first) 1580 { 1581 struct sock_filter filter[] = { 1582 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1583 }; 1584 struct sock_fprog prog = { 1585 .len = (unsigned short)ARRAY_SIZE(filter), 1586 .filter = filter, 1587 }; 1588 long ret; 1589 1590 ret = prctl(PR_SET_NO_NEW_PRIVS, 1, NULL, 0, 0); 1591 ASSERT_EQ(0, ret) { 1592 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1593 } 1594 1595 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FLAG_FILTER_TSYNC, 1596 &prog); 1597 ASSERT_NE(ENOSYS, errno) { 1598 TH_LOG("Kernel does not support seccomp syscall!"); 1599 } 1600 EXPECT_EQ(0, ret) { 1601 TH_LOG("Could not install initial filter with TSYNC!"); 1602 } 1603 } 1604 1605 #define TSYNC_SIBLINGS 2 1606 struct tsync_sibling { 1607 pthread_t tid; 1608 pid_t system_tid; 1609 sem_t *started; 1610 pthread_cond_t *cond; 1611 pthread_mutex_t *mutex; 1612 int diverge; 1613 int num_waits; 1614 struct sock_fprog *prog; 1615 struct __test_metadata *metadata; 1616 }; 1617 1618 FIXTURE_DATA(TSYNC) { 1619 struct sock_fprog root_prog, apply_prog; 1620 struct tsync_sibling sibling[TSYNC_SIBLINGS]; 1621 sem_t started; 1622 pthread_cond_t cond; 1623 pthread_mutex_t mutex; 1624 int sibling_count; 1625 }; 1626 1627 FIXTURE_SETUP(TSYNC) 1628 { 1629 struct sock_filter root_filter[] = { 1630 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1631 }; 1632 struct sock_filter apply_filter[] = { 1633 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 1634 offsetof(struct seccomp_data, nr)), 1635 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1), 1636 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 1637 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1638 }; 1639 1640 memset(&self->root_prog, 0, sizeof(self->root_prog)); 1641 memset(&self->apply_prog, 0, sizeof(self->apply_prog)); 1642 memset(&self->sibling, 0, sizeof(self->sibling)); 1643 self->root_prog.filter = malloc(sizeof(root_filter)); 1644 ASSERT_NE(NULL, self->root_prog.filter); 1645 memcpy(self->root_prog.filter, &root_filter, sizeof(root_filter)); 1646 self->root_prog.len = (unsigned short)ARRAY_SIZE(root_filter); 1647 1648 self->apply_prog.filter = malloc(sizeof(apply_filter)); 1649 ASSERT_NE(NULL, self->apply_prog.filter); 1650 memcpy(self->apply_prog.filter, &apply_filter, sizeof(apply_filter)); 1651 self->apply_prog.len = (unsigned short)ARRAY_SIZE(apply_filter); 1652 1653 self->sibling_count = 0; 1654 pthread_mutex_init(&self->mutex, NULL); 1655 pthread_cond_init(&self->cond, NULL); 1656 sem_init(&self->started, 0, 0); 1657 self->sibling[0].tid = 0; 1658 self->sibling[0].cond = &self->cond; 1659 self->sibling[0].started = &self->started; 1660 self->sibling[0].mutex = &self->mutex; 1661 self->sibling[0].diverge = 0; 1662 self->sibling[0].num_waits = 1; 1663 self->sibling[0].prog = &self->root_prog; 1664 self->sibling[0].metadata = _metadata; 1665 self->sibling[1].tid = 0; 1666 self->sibling[1].cond = &self->cond; 1667 self->sibling[1].started = &self->started; 1668 self->sibling[1].mutex = &self->mutex; 1669 self->sibling[1].diverge = 0; 1670 self->sibling[1].prog = &self->root_prog; 1671 self->sibling[1].num_waits = 1; 1672 self->sibling[1].metadata = _metadata; 1673 } 1674 1675 FIXTURE_TEARDOWN(TSYNC) 1676 { 1677 int sib = 0; 1678 1679 if (self->root_prog.filter) 1680 free(self->root_prog.filter); 1681 if (self->apply_prog.filter) 1682 free(self->apply_prog.filter); 1683 1684 for ( ; sib < self->sibling_count; ++sib) { 1685 struct tsync_sibling *s = &self->sibling[sib]; 1686 void *status; 1687 1688 if (!s->tid) 1689 continue; 1690 if (pthread_kill(s->tid, 0)) { 1691 pthread_cancel(s->tid); 1692 pthread_join(s->tid, &status); 1693 } 1694 } 1695 pthread_mutex_destroy(&self->mutex); 1696 pthread_cond_destroy(&self->cond); 1697 sem_destroy(&self->started); 1698 } 1699 1700 void *tsync_sibling(void *data) 1701 { 1702 long ret = 0; 1703 struct tsync_sibling *me = data; 1704 1705 me->system_tid = syscall(__NR_gettid); 1706 1707 pthread_mutex_lock(me->mutex); 1708 if (me->diverge) { 1709 /* Just re-apply the root prog to fork the tree */ 1710 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, 1711 me->prog, 0, 0); 1712 } 1713 sem_post(me->started); 1714 /* Return outside of started so parent notices failures. */ 1715 if (ret) { 1716 pthread_mutex_unlock(me->mutex); 1717 return (void *)SIBLING_EXIT_FAILURE; 1718 } 1719 do { 1720 pthread_cond_wait(me->cond, me->mutex); 1721 me->num_waits = me->num_waits - 1; 1722 } while (me->num_waits); 1723 pthread_mutex_unlock(me->mutex); 1724 1725 ret = prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0); 1726 if (!ret) 1727 return (void *)SIBLING_EXIT_NEWPRIVS; 1728 read(0, NULL, 0); 1729 return (void *)SIBLING_EXIT_UNKILLED; 1730 } 1731 1732 void tsync_start_sibling(struct tsync_sibling *sibling) 1733 { 1734 pthread_create(&sibling->tid, NULL, tsync_sibling, (void *)sibling); 1735 } 1736 1737 TEST_F(TSYNC, siblings_fail_prctl) 1738 { 1739 long ret; 1740 void *status; 1741 struct sock_filter filter[] = { 1742 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 1743 offsetof(struct seccomp_data, nr)), 1744 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_prctl, 0, 1), 1745 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | EINVAL), 1746 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 1747 }; 1748 struct sock_fprog prog = { 1749 .len = (unsigned short)ARRAY_SIZE(filter), 1750 .filter = filter, 1751 }; 1752 1753 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 1754 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1755 } 1756 1757 /* Check prctl failure detection by requesting sib 0 diverge. */ 1758 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog); 1759 ASSERT_NE(ENOSYS, errno) { 1760 TH_LOG("Kernel does not support seccomp syscall!"); 1761 } 1762 ASSERT_EQ(0, ret) { 1763 TH_LOG("setting filter failed"); 1764 } 1765 1766 self->sibling[0].diverge = 1; 1767 tsync_start_sibling(&self->sibling[0]); 1768 tsync_start_sibling(&self->sibling[1]); 1769 1770 while (self->sibling_count < TSYNC_SIBLINGS) { 1771 sem_wait(&self->started); 1772 self->sibling_count++; 1773 } 1774 1775 /* Signal the threads to clean up*/ 1776 pthread_mutex_lock(&self->mutex); 1777 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 1778 TH_LOG("cond broadcast non-zero"); 1779 } 1780 pthread_mutex_unlock(&self->mutex); 1781 1782 /* Ensure diverging sibling failed to call prctl. */ 1783 pthread_join(self->sibling[0].tid, &status); 1784 EXPECT_EQ(SIBLING_EXIT_FAILURE, (long)status); 1785 pthread_join(self->sibling[1].tid, &status); 1786 EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status); 1787 } 1788 1789 TEST_F(TSYNC, two_siblings_with_ancestor) 1790 { 1791 long ret; 1792 void *status; 1793 1794 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 1795 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1796 } 1797 1798 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &self->root_prog); 1799 ASSERT_NE(ENOSYS, errno) { 1800 TH_LOG("Kernel does not support seccomp syscall!"); 1801 } 1802 ASSERT_EQ(0, ret) { 1803 TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER!"); 1804 } 1805 tsync_start_sibling(&self->sibling[0]); 1806 tsync_start_sibling(&self->sibling[1]); 1807 1808 while (self->sibling_count < TSYNC_SIBLINGS) { 1809 sem_wait(&self->started); 1810 self->sibling_count++; 1811 } 1812 1813 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FLAG_FILTER_TSYNC, 1814 &self->apply_prog); 1815 ASSERT_EQ(0, ret) { 1816 TH_LOG("Could install filter on all threads!"); 1817 } 1818 /* Tell the siblings to test the policy */ 1819 pthread_mutex_lock(&self->mutex); 1820 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 1821 TH_LOG("cond broadcast non-zero"); 1822 } 1823 pthread_mutex_unlock(&self->mutex); 1824 /* Ensure they are both killed and don't exit cleanly. */ 1825 pthread_join(self->sibling[0].tid, &status); 1826 EXPECT_EQ(0x0, (long)status); 1827 pthread_join(self->sibling[1].tid, &status); 1828 EXPECT_EQ(0x0, (long)status); 1829 } 1830 1831 TEST_F(TSYNC, two_sibling_want_nnp) 1832 { 1833 void *status; 1834 1835 /* start siblings before any prctl() operations */ 1836 tsync_start_sibling(&self->sibling[0]); 1837 tsync_start_sibling(&self->sibling[1]); 1838 while (self->sibling_count < TSYNC_SIBLINGS) { 1839 sem_wait(&self->started); 1840 self->sibling_count++; 1841 } 1842 1843 /* Tell the siblings to test no policy */ 1844 pthread_mutex_lock(&self->mutex); 1845 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 1846 TH_LOG("cond broadcast non-zero"); 1847 } 1848 pthread_mutex_unlock(&self->mutex); 1849 1850 /* Ensure they are both upset about lacking nnp. */ 1851 pthread_join(self->sibling[0].tid, &status); 1852 EXPECT_EQ(SIBLING_EXIT_NEWPRIVS, (long)status); 1853 pthread_join(self->sibling[1].tid, &status); 1854 EXPECT_EQ(SIBLING_EXIT_NEWPRIVS, (long)status); 1855 } 1856 1857 TEST_F(TSYNC, two_siblings_with_no_filter) 1858 { 1859 long ret; 1860 void *status; 1861 1862 /* start siblings before any prctl() operations */ 1863 tsync_start_sibling(&self->sibling[0]); 1864 tsync_start_sibling(&self->sibling[1]); 1865 while (self->sibling_count < TSYNC_SIBLINGS) { 1866 sem_wait(&self->started); 1867 self->sibling_count++; 1868 } 1869 1870 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 1871 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1872 } 1873 1874 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FLAG_FILTER_TSYNC, 1875 &self->apply_prog); 1876 ASSERT_NE(ENOSYS, errno) { 1877 TH_LOG("Kernel does not support seccomp syscall!"); 1878 } 1879 ASSERT_EQ(0, ret) { 1880 TH_LOG("Could install filter on all threads!"); 1881 } 1882 1883 /* Tell the siblings to test the policy */ 1884 pthread_mutex_lock(&self->mutex); 1885 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 1886 TH_LOG("cond broadcast non-zero"); 1887 } 1888 pthread_mutex_unlock(&self->mutex); 1889 1890 /* Ensure they are both killed and don't exit cleanly. */ 1891 pthread_join(self->sibling[0].tid, &status); 1892 EXPECT_EQ(0x0, (long)status); 1893 pthread_join(self->sibling[1].tid, &status); 1894 EXPECT_EQ(0x0, (long)status); 1895 } 1896 1897 TEST_F(TSYNC, two_siblings_with_one_divergence) 1898 { 1899 long ret; 1900 void *status; 1901 1902 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 1903 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1904 } 1905 1906 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &self->root_prog); 1907 ASSERT_NE(ENOSYS, errno) { 1908 TH_LOG("Kernel does not support seccomp syscall!"); 1909 } 1910 ASSERT_EQ(0, ret) { 1911 TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER!"); 1912 } 1913 self->sibling[0].diverge = 1; 1914 tsync_start_sibling(&self->sibling[0]); 1915 tsync_start_sibling(&self->sibling[1]); 1916 1917 while (self->sibling_count < TSYNC_SIBLINGS) { 1918 sem_wait(&self->started); 1919 self->sibling_count++; 1920 } 1921 1922 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FLAG_FILTER_TSYNC, 1923 &self->apply_prog); 1924 ASSERT_EQ(self->sibling[0].system_tid, ret) { 1925 TH_LOG("Did not fail on diverged sibling."); 1926 } 1927 1928 /* Wake the threads */ 1929 pthread_mutex_lock(&self->mutex); 1930 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 1931 TH_LOG("cond broadcast non-zero"); 1932 } 1933 pthread_mutex_unlock(&self->mutex); 1934 1935 /* Ensure they are both unkilled. */ 1936 pthread_join(self->sibling[0].tid, &status); 1937 EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status); 1938 pthread_join(self->sibling[1].tid, &status); 1939 EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status); 1940 } 1941 1942 TEST_F(TSYNC, two_siblings_not_under_filter) 1943 { 1944 long ret, sib; 1945 void *status; 1946 1947 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 1948 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 1949 } 1950 1951 /* 1952 * Sibling 0 will have its own seccomp policy 1953 * and Sibling 1 will not be under seccomp at 1954 * all. Sibling 1 will enter seccomp and 0 1955 * will cause failure. 1956 */ 1957 self->sibling[0].diverge = 1; 1958 tsync_start_sibling(&self->sibling[0]); 1959 tsync_start_sibling(&self->sibling[1]); 1960 1961 while (self->sibling_count < TSYNC_SIBLINGS) { 1962 sem_wait(&self->started); 1963 self->sibling_count++; 1964 } 1965 1966 ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &self->root_prog); 1967 ASSERT_NE(ENOSYS, errno) { 1968 TH_LOG("Kernel does not support seccomp syscall!"); 1969 } 1970 ASSERT_EQ(0, ret) { 1971 TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER!"); 1972 } 1973 1974 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FLAG_FILTER_TSYNC, 1975 &self->apply_prog); 1976 ASSERT_EQ(ret, self->sibling[0].system_tid) { 1977 TH_LOG("Did not fail on diverged sibling."); 1978 } 1979 sib = 1; 1980 if (ret == self->sibling[0].system_tid) 1981 sib = 0; 1982 1983 pthread_mutex_lock(&self->mutex); 1984 1985 /* Increment the other siblings num_waits so we can clean up 1986 * the one we just saw. 1987 */ 1988 self->sibling[!sib].num_waits += 1; 1989 1990 /* Signal the thread to clean up*/ 1991 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 1992 TH_LOG("cond broadcast non-zero"); 1993 } 1994 pthread_mutex_unlock(&self->mutex); 1995 pthread_join(self->sibling[sib].tid, &status); 1996 EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status); 1997 /* Poll for actual task death. pthread_join doesn't guarantee it. */ 1998 while (!kill(self->sibling[sib].system_tid, 0)) 1999 sleep(0.1); 2000 /* Switch to the remaining sibling */ 2001 sib = !sib; 2002 2003 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FLAG_FILTER_TSYNC, 2004 &self->apply_prog); 2005 ASSERT_EQ(0, ret) { 2006 TH_LOG("Expected the remaining sibling to sync"); 2007 }; 2008 2009 pthread_mutex_lock(&self->mutex); 2010 2011 /* If remaining sibling didn't have a chance to wake up during 2012 * the first broadcast, manually reduce the num_waits now. 2013 */ 2014 if (self->sibling[sib].num_waits > 1) 2015 self->sibling[sib].num_waits = 1; 2016 ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) { 2017 TH_LOG("cond broadcast non-zero"); 2018 } 2019 pthread_mutex_unlock(&self->mutex); 2020 pthread_join(self->sibling[sib].tid, &status); 2021 EXPECT_EQ(0, (long)status); 2022 /* Poll for actual task death. pthread_join doesn't guarantee it. */ 2023 while (!kill(self->sibling[sib].system_tid, 0)) 2024 sleep(0.1); 2025 2026 ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FLAG_FILTER_TSYNC, 2027 &self->apply_prog); 2028 ASSERT_EQ(0, ret); /* just us chickens */ 2029 } 2030 2031 /* Make sure restarted syscalls are seen directly as "restart_syscall". */ 2032 TEST(syscall_restart) 2033 { 2034 long ret; 2035 unsigned long msg; 2036 pid_t child_pid; 2037 int pipefd[2]; 2038 int status; 2039 siginfo_t info = { }; 2040 struct sock_filter filter[] = { 2041 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 2042 offsetof(struct seccomp_data, nr)), 2043 2044 #ifdef __NR_sigreturn 2045 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_sigreturn, 6, 0), 2046 #endif 2047 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 5, 0), 2048 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_exit, 4, 0), 2049 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_rt_sigreturn, 3, 0), 2050 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_nanosleep, 4, 0), 2051 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_restart_syscall, 4, 0), 2052 2053 /* Allow __NR_write for easy logging. */ 2054 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_write, 0, 1), 2055 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), 2056 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL), 2057 /* The nanosleep jump target. */ 2058 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE|0x100), 2059 /* The restart_syscall jump target. */ 2060 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE|0x200), 2061 }; 2062 struct sock_fprog prog = { 2063 .len = (unsigned short)ARRAY_SIZE(filter), 2064 .filter = filter, 2065 }; 2066 #if defined(__arm__) 2067 struct utsname utsbuf; 2068 #endif 2069 2070 ASSERT_EQ(0, pipe(pipefd)); 2071 2072 child_pid = fork(); 2073 ASSERT_LE(0, child_pid); 2074 if (child_pid == 0) { 2075 /* Child uses EXPECT not ASSERT to deliver status correctly. */ 2076 char buf = ' '; 2077 struct timespec timeout = { }; 2078 2079 /* Attach parent as tracer and stop. */ 2080 EXPECT_EQ(0, ptrace(PTRACE_TRACEME)); 2081 EXPECT_EQ(0, raise(SIGSTOP)); 2082 2083 EXPECT_EQ(0, close(pipefd[1])); 2084 2085 EXPECT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 2086 TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); 2087 } 2088 2089 ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0); 2090 EXPECT_EQ(0, ret) { 2091 TH_LOG("Failed to install filter!"); 2092 } 2093 2094 EXPECT_EQ(1, read(pipefd[0], &buf, 1)) { 2095 TH_LOG("Failed to read() sync from parent"); 2096 } 2097 EXPECT_EQ('.', buf) { 2098 TH_LOG("Failed to get sync data from read()"); 2099 } 2100 2101 /* Start nanosleep to be interrupted. */ 2102 timeout.tv_sec = 1; 2103 errno = 0; 2104 EXPECT_EQ(0, nanosleep(&timeout, NULL)) { 2105 TH_LOG("Call to nanosleep() failed (errno %d)", errno); 2106 } 2107 2108 /* Read final sync from parent. */ 2109 EXPECT_EQ(1, read(pipefd[0], &buf, 1)) { 2110 TH_LOG("Failed final read() from parent"); 2111 } 2112 EXPECT_EQ('!', buf) { 2113 TH_LOG("Failed to get final data from read()"); 2114 } 2115 2116 /* Directly report the status of our test harness results. */ 2117 syscall(__NR_exit, _metadata->passed ? EXIT_SUCCESS 2118 : EXIT_FAILURE); 2119 } 2120 EXPECT_EQ(0, close(pipefd[0])); 2121 2122 /* Attach to child, setup options, and release. */ 2123 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2124 ASSERT_EQ(true, WIFSTOPPED(status)); 2125 ASSERT_EQ(0, ptrace(PTRACE_SETOPTIONS, child_pid, NULL, 2126 PTRACE_O_TRACESECCOMP)); 2127 ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0)); 2128 ASSERT_EQ(1, write(pipefd[1], ".", 1)); 2129 2130 /* Wait for nanosleep() to start. */ 2131 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2132 ASSERT_EQ(true, WIFSTOPPED(status)); 2133 ASSERT_EQ(SIGTRAP, WSTOPSIG(status)); 2134 ASSERT_EQ(PTRACE_EVENT_SECCOMP, (status >> 16)); 2135 ASSERT_EQ(0, ptrace(PTRACE_GETEVENTMSG, child_pid, NULL, &msg)); 2136 ASSERT_EQ(0x100, msg); 2137 EXPECT_EQ(__NR_nanosleep, get_syscall(_metadata, child_pid)); 2138 2139 /* Might as well check siginfo for sanity while we're here. */ 2140 ASSERT_EQ(0, ptrace(PTRACE_GETSIGINFO, child_pid, NULL, &info)); 2141 ASSERT_EQ(SIGTRAP, info.si_signo); 2142 ASSERT_EQ(SIGTRAP | (PTRACE_EVENT_SECCOMP << 8), info.si_code); 2143 EXPECT_EQ(0, info.si_errno); 2144 EXPECT_EQ(getuid(), info.si_uid); 2145 /* Verify signal delivery came from child (seccomp-triggered). */ 2146 EXPECT_EQ(child_pid, info.si_pid); 2147 2148 /* Interrupt nanosleep with SIGSTOP (which we'll need to handle). */ 2149 ASSERT_EQ(0, kill(child_pid, SIGSTOP)); 2150 ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0)); 2151 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2152 ASSERT_EQ(true, WIFSTOPPED(status)); 2153 ASSERT_EQ(SIGSTOP, WSTOPSIG(status)); 2154 /* Verify signal delivery came from parent now. */ 2155 ASSERT_EQ(0, ptrace(PTRACE_GETSIGINFO, child_pid, NULL, &info)); 2156 EXPECT_EQ(getpid(), info.si_pid); 2157 2158 /* Restart nanosleep with SIGCONT, which triggers restart_syscall. */ 2159 ASSERT_EQ(0, kill(child_pid, SIGCONT)); 2160 ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0)); 2161 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2162 ASSERT_EQ(true, WIFSTOPPED(status)); 2163 ASSERT_EQ(SIGCONT, WSTOPSIG(status)); 2164 ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0)); 2165 2166 /* Wait for restart_syscall() to start. */ 2167 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2168 ASSERT_EQ(true, WIFSTOPPED(status)); 2169 ASSERT_EQ(SIGTRAP, WSTOPSIG(status)); 2170 ASSERT_EQ(PTRACE_EVENT_SECCOMP, (status >> 16)); 2171 ASSERT_EQ(0, ptrace(PTRACE_GETEVENTMSG, child_pid, NULL, &msg)); 2172 2173 ASSERT_EQ(0x200, msg); 2174 ret = get_syscall(_metadata, child_pid); 2175 #if defined(__arm__) 2176 /* 2177 * FIXME: 2178 * - native ARM registers do NOT expose true syscall. 2179 * - compat ARM registers on ARM64 DO expose true syscall. 2180 */ 2181 ASSERT_EQ(0, uname(&utsbuf)); 2182 if (strncmp(utsbuf.machine, "arm", 3) == 0) { 2183 EXPECT_EQ(__NR_nanosleep, ret); 2184 } else 2185 #endif 2186 { 2187 EXPECT_EQ(__NR_restart_syscall, ret); 2188 } 2189 2190 /* Write again to end test. */ 2191 ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0)); 2192 ASSERT_EQ(1, write(pipefd[1], "!", 1)); 2193 EXPECT_EQ(0, close(pipefd[1])); 2194 2195 ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); 2196 if (WIFSIGNALED(status) || WEXITSTATUS(status)) 2197 _metadata->passed = 0; 2198 } 2199 2200 /* 2201 * TODO: 2202 * - add microbenchmarks 2203 * - expand NNP testing 2204 * - better arch-specific TRACE and TRAP handlers. 2205 * - endianness checking when appropriate 2206 * - 64-bit arg prodding 2207 * - arch value testing (x86 modes especially) 2208 * - ... 2209 */ 2210 2211 TEST_HARNESS_MAIN 2212