1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2013 The FreeBSD Foundation 5 * Copyright (c) 2013 Mariusz Zaborski <oshogbo@FreeBSD.org> 6 * All rights reserved. 7 * 8 * This software was developed by Pawel Jakub Dawidek under sponsorship from 9 * the FreeBSD Foundation. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include <sys/param.h> 37 #include <sys/socket.h> 38 #include <sys/select.h> 39 40 #include <errno.h> 41 #include <fcntl.h> 42 #include <stdbool.h> 43 #include <stdint.h> 44 #include <stdlib.h> 45 #include <string.h> 46 #include <unistd.h> 47 48 #ifdef HAVE_PJDLOG 49 #include <pjdlog.h> 50 #endif 51 52 #include "common_impl.h" 53 #include "msgio.h" 54 55 #ifndef HAVE_PJDLOG 56 #include <assert.h> 57 #define PJDLOG_ASSERT(...) assert(__VA_ARGS__) 58 #define PJDLOG_RASSERT(expr, ...) assert(expr) 59 #define PJDLOG_ABORT(...) abort() 60 #endif 61 62 #ifdef __linux__ 63 /* Linux: arbitrary size, but must be lower than SCM_MAX_FD. */ 64 #define PKG_MAX_SIZE ((64U - 1) * CMSG_SPACE(sizeof(int))) 65 #else 66 /* 67 * To work around limitations in 32-bit emulation on 64-bit kernels, use a 68 * machine-independent limit on the number of FDs per message. Each control 69 * message contains 1 FD and requires 12 bytes for the header, 4 pad bytes, 70 * 4 bytes for the descriptor, and another 4 pad bytes. 71 */ 72 #define PKG_MAX_SIZE (MCLBYTES / 24) 73 #endif 74 75 static int 76 msghdr_add_fd(struct cmsghdr *cmsg, int fd) 77 { 78 79 PJDLOG_ASSERT(fd >= 0); 80 81 cmsg->cmsg_level = SOL_SOCKET; 82 cmsg->cmsg_type = SCM_RIGHTS; 83 cmsg->cmsg_len = CMSG_LEN(sizeof(fd)); 84 bcopy(&fd, CMSG_DATA(cmsg), sizeof(fd)); 85 86 return (0); 87 } 88 89 static void 90 fd_wait(int fd, bool doread) 91 { 92 fd_set fds; 93 94 PJDLOG_ASSERT(fd >= 0); 95 96 FD_ZERO(&fds); 97 FD_SET(fd, &fds); 98 (void)select(fd + 1, doread ? &fds : NULL, doread ? NULL : &fds, 99 NULL, NULL); 100 } 101 102 static int 103 msg_recv(int sock, struct msghdr *msg) 104 { 105 int flags; 106 107 PJDLOG_ASSERT(sock >= 0); 108 109 #ifdef MSG_CMSG_CLOEXEC 110 flags = MSG_CMSG_CLOEXEC; 111 #else 112 flags = 0; 113 #endif 114 115 for (;;) { 116 fd_wait(sock, true); 117 if (recvmsg(sock, msg, flags) == -1) { 118 if (errno == EINTR) 119 continue; 120 return (-1); 121 } 122 break; 123 } 124 125 return (0); 126 } 127 128 static int 129 msg_send(int sock, const struct msghdr *msg) 130 { 131 132 PJDLOG_ASSERT(sock >= 0); 133 134 for (;;) { 135 fd_wait(sock, false); 136 if (sendmsg(sock, msg, 0) == -1) { 137 if (errno == EINTR) 138 continue; 139 return (-1); 140 } 141 break; 142 } 143 144 return (0); 145 } 146 147 #ifdef __FreeBSD__ 148 int 149 cred_send(int sock) 150 { 151 unsigned char credbuf[CMSG_SPACE(sizeof(struct cmsgcred))]; 152 struct msghdr msg; 153 struct cmsghdr *cmsg; 154 struct iovec iov; 155 uint8_t dummy; 156 157 bzero(credbuf, sizeof(credbuf)); 158 bzero(&msg, sizeof(msg)); 159 bzero(&iov, sizeof(iov)); 160 161 /* 162 * XXX: We send one byte along with the control message, because 163 * setting msg_iov to NULL only works if this is the first 164 * packet send over the socket. Once we send some data we 165 * won't be able to send credentials anymore. This is most 166 * likely a kernel bug. 167 */ 168 dummy = 0; 169 iov.iov_base = &dummy; 170 iov.iov_len = sizeof(dummy); 171 172 msg.msg_iov = &iov; 173 msg.msg_iovlen = 1; 174 msg.msg_control = credbuf; 175 msg.msg_controllen = sizeof(credbuf); 176 177 cmsg = CMSG_FIRSTHDR(&msg); 178 cmsg->cmsg_len = CMSG_LEN(sizeof(struct cmsgcred)); 179 cmsg->cmsg_level = SOL_SOCKET; 180 cmsg->cmsg_type = SCM_CREDS; 181 182 if (msg_send(sock, &msg) == -1) 183 return (-1); 184 185 return (0); 186 } 187 188 int 189 cred_recv(int sock, struct cmsgcred *cred) 190 { 191 unsigned char credbuf[CMSG_SPACE(sizeof(struct cmsgcred))]; 192 struct msghdr msg; 193 struct cmsghdr *cmsg; 194 struct iovec iov; 195 uint8_t dummy; 196 197 bzero(credbuf, sizeof(credbuf)); 198 bzero(&msg, sizeof(msg)); 199 bzero(&iov, sizeof(iov)); 200 201 iov.iov_base = &dummy; 202 iov.iov_len = sizeof(dummy); 203 204 msg.msg_iov = &iov; 205 msg.msg_iovlen = 1; 206 msg.msg_control = credbuf; 207 msg.msg_controllen = sizeof(credbuf); 208 209 if (msg_recv(sock, &msg) == -1) 210 return (-1); 211 212 cmsg = CMSG_FIRSTHDR(&msg); 213 if (cmsg == NULL || 214 cmsg->cmsg_len != CMSG_LEN(sizeof(struct cmsgcred)) || 215 cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_CREDS) { 216 errno = EINVAL; 217 return (-1); 218 } 219 bcopy(CMSG_DATA(cmsg), cred, sizeof(*cred)); 220 221 return (0); 222 } 223 #endif 224 225 static int 226 fd_package_send(int sock, const int *fds, size_t nfds) 227 { 228 struct msghdr msg; 229 struct cmsghdr *cmsg; 230 struct iovec iov; 231 unsigned int i; 232 int serrno, ret; 233 uint8_t dummy; 234 235 PJDLOG_ASSERT(sock >= 0); 236 PJDLOG_ASSERT(fds != NULL); 237 PJDLOG_ASSERT(nfds > 0); 238 239 bzero(&msg, sizeof(msg)); 240 241 /* 242 * XXX: Look into cred_send function for more details. 243 */ 244 dummy = 0; 245 iov.iov_base = &dummy; 246 iov.iov_len = sizeof(dummy); 247 248 msg.msg_iov = &iov; 249 msg.msg_iovlen = 1; 250 msg.msg_controllen = nfds * CMSG_SPACE(sizeof(int)); 251 msg.msg_control = calloc(1, msg.msg_controllen); 252 if (msg.msg_control == NULL) 253 return (-1); 254 255 ret = -1; 256 257 for (i = 0, cmsg = CMSG_FIRSTHDR(&msg); i < nfds && cmsg != NULL; 258 i++, cmsg = CMSG_NXTHDR(&msg, cmsg)) { 259 if (msghdr_add_fd(cmsg, fds[i]) == -1) 260 goto end; 261 } 262 263 if (msg_send(sock, &msg) == -1) 264 goto end; 265 266 ret = 0; 267 end: 268 serrno = errno; 269 free(msg.msg_control); 270 errno = serrno; 271 return (ret); 272 } 273 274 static int 275 fd_package_recv(int sock, int *fds, size_t nfds) 276 { 277 struct msghdr msg; 278 struct cmsghdr *cmsg; 279 unsigned int i; 280 int serrno, ret; 281 struct iovec iov; 282 uint8_t dummy; 283 284 PJDLOG_ASSERT(sock >= 0); 285 PJDLOG_ASSERT(nfds > 0); 286 PJDLOG_ASSERT(fds != NULL); 287 288 bzero(&msg, sizeof(msg)); 289 bzero(&iov, sizeof(iov)); 290 291 /* 292 * XXX: Look into cred_send function for more details. 293 */ 294 iov.iov_base = &dummy; 295 iov.iov_len = sizeof(dummy); 296 297 msg.msg_iov = &iov; 298 msg.msg_iovlen = 1; 299 msg.msg_controllen = nfds * CMSG_SPACE(sizeof(int)); 300 msg.msg_control = calloc(1, msg.msg_controllen); 301 if (msg.msg_control == NULL) 302 return (-1); 303 304 ret = -1; 305 306 if (msg_recv(sock, &msg) == -1) 307 goto end; 308 309 i = 0; 310 cmsg = CMSG_FIRSTHDR(&msg); 311 while (cmsg && i < nfds) { 312 unsigned int n; 313 314 if (cmsg->cmsg_level != SOL_SOCKET || 315 cmsg->cmsg_type != SCM_RIGHTS) { 316 errno = EINVAL; 317 break; 318 } 319 n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int); 320 if (i + n > nfds) { 321 errno = EINVAL; 322 break; 323 } 324 bcopy(CMSG_DATA(cmsg), fds + i, sizeof(int) * n); 325 cmsg = CMSG_NXTHDR(&msg, cmsg); 326 i += n; 327 } 328 329 if (cmsg != NULL || i < nfds) { 330 unsigned int last; 331 332 /* 333 * We need to close all received descriptors, even if we have 334 * different control message (eg. SCM_CREDS) in between. 335 */ 336 last = i; 337 for (i = 0; i < last; i++) { 338 if (fds[i] >= 0) { 339 close(fds[i]); 340 } 341 } 342 errno = EINVAL; 343 goto end; 344 } 345 346 #ifndef MSG_CMSG_CLOEXEC 347 /* 348 * If the MSG_CMSG_CLOEXEC flag is not available we cannot set the 349 * close-on-exec flag atomically, but we still want to set it for 350 * consistency. 351 */ 352 for (i = 0; i < nfds; i++) { 353 (void) fcntl(fds[i], F_SETFD, FD_CLOEXEC); 354 } 355 #endif 356 357 ret = 0; 358 end: 359 serrno = errno; 360 free(msg.msg_control); 361 errno = serrno; 362 return (ret); 363 } 364 365 int 366 fd_recv(int sock, int *fds, size_t nfds) 367 { 368 unsigned int i, step, j; 369 int ret, serrno; 370 371 if (nfds == 0 || fds == NULL) { 372 errno = EINVAL; 373 return (-1); 374 } 375 376 ret = i = step = 0; 377 while (i < nfds) { 378 if (PKG_MAX_SIZE < nfds - i) 379 step = PKG_MAX_SIZE; 380 else 381 step = nfds - i; 382 ret = fd_package_recv(sock, fds + i, step); 383 if (ret != 0) { 384 /* Close all received descriptors. */ 385 serrno = errno; 386 for (j = 0; j < i; j++) 387 close(fds[j]); 388 errno = serrno; 389 break; 390 } 391 i += step; 392 } 393 394 return (ret); 395 } 396 397 int 398 fd_send(int sock, const int *fds, size_t nfds) 399 { 400 unsigned int i, step; 401 int ret; 402 403 if (nfds == 0 || fds == NULL) { 404 errno = EINVAL; 405 return (-1); 406 } 407 408 ret = i = step = 0; 409 while (i < nfds) { 410 if (PKG_MAX_SIZE < nfds - i) 411 step = PKG_MAX_SIZE; 412 else 413 step = nfds - i; 414 ret = fd_package_send(sock, fds + i, step); 415 if (ret != 0) 416 break; 417 i += step; 418 } 419 420 return (ret); 421 } 422 423 int 424 buf_send(int sock, void *buf, size_t size) 425 { 426 ssize_t done; 427 unsigned char *ptr; 428 429 PJDLOG_ASSERT(sock >= 0); 430 PJDLOG_ASSERT(size > 0); 431 PJDLOG_ASSERT(buf != NULL); 432 433 ptr = buf; 434 do { 435 fd_wait(sock, false); 436 done = send(sock, ptr, size, 0); 437 if (done == -1) { 438 if (errno == EINTR) 439 continue; 440 return (-1); 441 } else if (done == 0) { 442 errno = ENOTCONN; 443 return (-1); 444 } 445 size -= done; 446 ptr += done; 447 } while (size > 0); 448 449 return (0); 450 } 451 452 int 453 buf_recv(int sock, void *buf, size_t size, int flags) 454 { 455 ssize_t done; 456 unsigned char *ptr; 457 458 PJDLOG_ASSERT(sock >= 0); 459 PJDLOG_ASSERT(buf != NULL); 460 461 ptr = buf; 462 while (size > 0) { 463 fd_wait(sock, true); 464 done = recv(sock, ptr, size, flags); 465 if (done == -1) { 466 if (errno == EINTR) 467 continue; 468 return (-1); 469 } else if (done == 0) { 470 errno = ENOTCONN; 471 return (-1); 472 } 473 size -= done; 474 ptr += done; 475 } 476 477 return (0); 478 } 479