1 // SPDX-License-Identifier: GPL-2.0 2 3 #include <assert.h> 4 #include <errno.h> 5 #include <fcntl.h> 6 #include <limits.h> 7 #include <linux/coredump.h> 8 #include <linux/fs.h> 9 #include <pthread.h> 10 #include <stdbool.h> 11 #include <stdio.h> 12 #include <stdlib.h> 13 #include <string.h> 14 #include <sys/epoll.h> 15 #include <sys/ioctl.h> 16 #include <sys/socket.h> 17 #include <sys/types.h> 18 #include <sys/un.h> 19 #include <sys/wait.h> 20 #include <unistd.h> 21 22 #include "../filesystems/wrappers.h" 23 #include "../pidfd/pidfd.h" 24 25 /* Forward declarations to avoid including harness header */ 26 struct __test_metadata; 27 28 /* Match the fixture definition from coredump_test.h */ 29 struct _fixture_coredump_data { 30 char original_core_pattern[256]; 31 pid_t pid_coredump_server; 32 int fd_tmpfs_detached; 33 }; 34 35 #ifndef PAGE_SIZE 36 #define PAGE_SIZE 4096 37 #endif 38 39 #define NUM_THREAD_SPAWN 128 40 41 void *do_nothing(void *arg) 42 { 43 (void)arg; 44 while (1) 45 pause(); 46 47 return NULL; 48 } 49 50 void crashing_child(void) 51 { 52 pthread_t thread; 53 int i; 54 55 for (i = 0; i < NUM_THREAD_SPAWN; ++i) 56 pthread_create(&thread, NULL, do_nothing, NULL); 57 58 /* crash on purpose */ 59 __builtin_trap(); 60 } 61 62 int create_detached_tmpfs(void) 63 { 64 int fd_context, fd_tmpfs; 65 66 fd_context = sys_fsopen("tmpfs", 0); 67 if (fd_context < 0) 68 return -1; 69 70 if (sys_fsconfig(fd_context, FSCONFIG_CMD_CREATE, NULL, NULL, 0) < 0) 71 return -1; 72 73 fd_tmpfs = sys_fsmount(fd_context, 0, 0); 74 close(fd_context); 75 return fd_tmpfs; 76 } 77 78 int create_and_listen_unix_socket(const char *path) 79 { 80 struct sockaddr_un addr = { 81 .sun_family = AF_UNIX, 82 }; 83 assert(strlen(path) < sizeof(addr.sun_path) - 1); 84 strncpy(addr.sun_path, path, sizeof(addr.sun_path) - 1); 85 size_t addr_len = 86 offsetof(struct sockaddr_un, sun_path) + strlen(path) + 1; 87 int fd, ret; 88 89 fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0); 90 if (fd < 0) 91 goto out; 92 93 ret = bind(fd, (const struct sockaddr *)&addr, addr_len); 94 if (ret < 0) 95 goto out; 96 97 ret = listen(fd, 128); 98 if (ret < 0) 99 goto out; 100 101 return fd; 102 103 out: 104 if (fd >= 0) 105 close(fd); 106 return -1; 107 } 108 109 bool set_core_pattern(const char *pattern) 110 { 111 int fd; 112 ssize_t ret; 113 114 fd = open("/proc/sys/kernel/core_pattern", O_WRONLY | O_CLOEXEC); 115 if (fd < 0) 116 return false; 117 118 ret = write(fd, pattern, strlen(pattern)); 119 close(fd); 120 if (ret < 0) 121 return false; 122 123 fprintf(stderr, "Set core_pattern to '%s' | %zu == %zu\n", pattern, ret, strlen(pattern)); 124 return ret == strlen(pattern); 125 } 126 127 int get_peer_pidfd(int fd) 128 { 129 int fd_peer_pidfd; 130 socklen_t fd_peer_pidfd_len = sizeof(fd_peer_pidfd); 131 int ret = getsockopt(fd, SOL_SOCKET, SO_PEERPIDFD, &fd_peer_pidfd, 132 &fd_peer_pidfd_len); 133 if (ret < 0) { 134 fprintf(stderr, "get_peer_pidfd: getsockopt(SO_PEERPIDFD) failed: %m\n"); 135 return -1; 136 } 137 fprintf(stderr, "get_peer_pidfd: successfully retrieved pidfd %d\n", fd_peer_pidfd); 138 return fd_peer_pidfd; 139 } 140 141 bool get_pidfd_info(int fd_peer_pidfd, struct pidfd_info *info) 142 { 143 int ret; 144 memset(info, 0, sizeof(*info)); 145 info->mask = PIDFD_INFO_EXIT | PIDFD_INFO_COREDUMP | PIDFD_INFO_COREDUMP_SIGNAL; 146 ret = ioctl(fd_peer_pidfd, PIDFD_GET_INFO, info); 147 if (ret < 0) { 148 fprintf(stderr, "get_pidfd_info: ioctl(PIDFD_GET_INFO) failed: %m\n"); 149 return false; 150 } 151 fprintf(stderr, "get_pidfd_info: mask=0x%llx, coredump_mask=0x%x, coredump_signal=%d\n", 152 (unsigned long long)info->mask, info->coredump_mask, info->coredump_signal); 153 return true; 154 } 155 156 /* Protocol helper functions */ 157 158 ssize_t recv_marker(int fd) 159 { 160 enum coredump_mark mark = COREDUMP_MARK_REQACK; 161 ssize_t ret; 162 163 ret = recv(fd, &mark, sizeof(mark), MSG_WAITALL); 164 if (ret != sizeof(mark)) 165 return -1; 166 167 switch (mark) { 168 case COREDUMP_MARK_REQACK: 169 fprintf(stderr, "Received marker: ReqAck\n"); 170 return COREDUMP_MARK_REQACK; 171 case COREDUMP_MARK_MINSIZE: 172 fprintf(stderr, "Received marker: MinSize\n"); 173 return COREDUMP_MARK_MINSIZE; 174 case COREDUMP_MARK_MAXSIZE: 175 fprintf(stderr, "Received marker: MaxSize\n"); 176 return COREDUMP_MARK_MAXSIZE; 177 case COREDUMP_MARK_UNSUPPORTED: 178 fprintf(stderr, "Received marker: Unsupported\n"); 179 return COREDUMP_MARK_UNSUPPORTED; 180 case COREDUMP_MARK_CONFLICTING: 181 fprintf(stderr, "Received marker: Conflicting\n"); 182 return COREDUMP_MARK_CONFLICTING; 183 default: 184 fprintf(stderr, "Received unknown marker: %u\n", mark); 185 break; 186 } 187 return -1; 188 } 189 190 bool read_marker(int fd, enum coredump_mark mark) 191 { 192 ssize_t ret; 193 194 ret = recv_marker(fd); 195 if (ret < 0) 196 return false; 197 return ret == mark; 198 } 199 200 bool read_coredump_req(int fd, struct coredump_req *req) 201 { 202 ssize_t ret; 203 size_t field_size, user_size, ack_size, kernel_size, remaining_size; 204 205 memset(req, 0, sizeof(*req)); 206 field_size = sizeof(req->size); 207 208 /* Peek the size of the coredump request. */ 209 ret = recv(fd, req, field_size, MSG_PEEK | MSG_WAITALL); 210 if (ret != field_size) { 211 fprintf(stderr, "read_coredump_req: peek failed (got %zd, expected %zu): %m\n", 212 ret, field_size); 213 return false; 214 } 215 kernel_size = req->size; 216 217 if (kernel_size < COREDUMP_ACK_SIZE_VER0) { 218 fprintf(stderr, "read_coredump_req: kernel_size %zu < min %d\n", 219 kernel_size, COREDUMP_ACK_SIZE_VER0); 220 return false; 221 } 222 if (kernel_size >= PAGE_SIZE) { 223 fprintf(stderr, "read_coredump_req: kernel_size %zu >= PAGE_SIZE %d\n", 224 kernel_size, PAGE_SIZE); 225 return false; 226 } 227 228 /* Use the minimum of user and kernel size to read the full request. */ 229 user_size = sizeof(struct coredump_req); 230 ack_size = user_size < kernel_size ? user_size : kernel_size; 231 ret = recv(fd, req, ack_size, MSG_WAITALL); 232 if (ret != ack_size) 233 return false; 234 235 fprintf(stderr, "Read coredump request with size %u and mask 0x%llx\n", 236 req->size, (unsigned long long)req->mask); 237 238 if (user_size > kernel_size) 239 remaining_size = user_size - kernel_size; 240 else 241 remaining_size = kernel_size - user_size; 242 243 if (PAGE_SIZE <= remaining_size) 244 return false; 245 246 /* 247 * Discard any additional data if the kernel's request was larger than 248 * what we knew about or cared about. 249 */ 250 if (remaining_size) { 251 char buffer[PAGE_SIZE]; 252 253 ret = recv(fd, buffer, sizeof(buffer), MSG_WAITALL); 254 if (ret != remaining_size) 255 return false; 256 fprintf(stderr, "Discarded %zu bytes of data after coredump request\n", remaining_size); 257 } 258 259 return true; 260 } 261 262 bool send_coredump_ack(int fd, const struct coredump_req *req, 263 __u64 mask, size_t size_ack) 264 { 265 ssize_t ret; 266 /* 267 * Wrap struct coredump_ack in a larger struct so we can 268 * simulate sending to much data to the kernel. 269 */ 270 struct large_ack_for_size_testing { 271 struct coredump_ack ack; 272 char buffer[PAGE_SIZE]; 273 } large_ack = {}; 274 275 if (!size_ack) 276 size_ack = sizeof(struct coredump_ack) < req->size_ack ? 277 sizeof(struct coredump_ack) : 278 req->size_ack; 279 large_ack.ack.mask = mask; 280 large_ack.ack.size = size_ack; 281 ret = send(fd, &large_ack, size_ack, MSG_NOSIGNAL); 282 if (ret != size_ack) 283 return false; 284 285 fprintf(stderr, "Sent coredump ack with size %zu and mask 0x%llx\n", 286 size_ack, (unsigned long long)mask); 287 return true; 288 } 289 290 bool check_coredump_req(const struct coredump_req *req, size_t min_size, 291 __u64 required_mask) 292 { 293 if (req->size < min_size) 294 return false; 295 if ((req->mask & required_mask) != required_mask) 296 return false; 297 if (req->mask & ~required_mask) 298 return false; 299 return true; 300 } 301 302 int open_coredump_tmpfile(int fd_tmpfs_detached) 303 { 304 return openat(fd_tmpfs_detached, ".", O_TMPFILE | O_RDWR | O_EXCL, 0600); 305 } 306 307 void process_coredump_worker(int fd_coredump, int fd_peer_pidfd, int fd_core_file) 308 { 309 int epfd = -1; 310 int exit_code = EXIT_FAILURE; 311 struct epoll_event ev; 312 int flags; 313 314 /* Set socket to non-blocking mode for edge-triggered epoll */ 315 flags = fcntl(fd_coredump, F_GETFL, 0); 316 if (flags < 0) { 317 fprintf(stderr, "Worker: fcntl(F_GETFL) failed: %m\n"); 318 goto out; 319 } 320 if (fcntl(fd_coredump, F_SETFL, flags | O_NONBLOCK) < 0) { 321 fprintf(stderr, "Worker: fcntl(F_SETFL, O_NONBLOCK) failed: %m\n"); 322 goto out; 323 } 324 325 epfd = epoll_create1(0); 326 if (epfd < 0) { 327 fprintf(stderr, "Worker: epoll_create1() failed: %m\n"); 328 goto out; 329 } 330 331 ev.events = EPOLLIN | EPOLLRDHUP | EPOLLET; 332 ev.data.fd = fd_coredump; 333 if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd_coredump, &ev) < 0) { 334 fprintf(stderr, "Worker: epoll_ctl(EPOLL_CTL_ADD) failed: %m\n"); 335 goto out; 336 } 337 338 for (;;) { 339 struct epoll_event events[1]; 340 int n = epoll_wait(epfd, events, 1, -1); 341 if (n < 0) { 342 fprintf(stderr, "Worker: epoll_wait() failed: %m\n"); 343 break; 344 } 345 346 if (events[0].events & (EPOLLIN | EPOLLRDHUP)) { 347 for (;;) { 348 char buffer[4096]; 349 ssize_t bytes_read = read(fd_coredump, buffer, sizeof(buffer)); 350 if (bytes_read < 0) { 351 if (errno == EAGAIN || errno == EWOULDBLOCK) 352 break; 353 fprintf(stderr, "Worker: read() failed: %m\n"); 354 goto out; 355 } 356 if (bytes_read == 0) 357 goto done; 358 ssize_t bytes_write = write(fd_core_file, buffer, bytes_read); 359 if (bytes_write != bytes_read) { 360 if (bytes_write < 0 && errno == ENOSPC) 361 continue; 362 fprintf(stderr, "Worker: write() failed (read=%zd, write=%zd): %m\n", 363 bytes_read, bytes_write); 364 goto out; 365 } 366 } 367 } 368 } 369 370 done: 371 exit_code = EXIT_SUCCESS; 372 fprintf(stderr, "Worker: completed successfully\n"); 373 out: 374 if (epfd >= 0) 375 close(epfd); 376 if (fd_core_file >= 0) 377 close(fd_core_file); 378 if (fd_peer_pidfd >= 0) 379 close(fd_peer_pidfd); 380 if (fd_coredump >= 0) 381 close(fd_coredump); 382 _exit(exit_code); 383 } 384