contrib/dhcpcd/src/privsep-root.c

   1 /* SPDX-License-Identifier: BSD-2-Clause */
   2 /*
   3  * Privilege Separation for dhcpcd, privileged actioneer
   4  * Copyright (c) 2006-2020 Roy Marples <roy@marples.name>
   5  * All rights reserved
   6
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #include <sys/ioctl.h>
  30 #include <sys/socket.h>
  31 #include <sys/stat.h>
  32 #include <sys/time.h>
  33 #include <sys/types.h>
  34 #include <sys/wait.h>
  35
  36 #include <assert.h>
  37 #include <errno.h>
  38 #include <fcntl.h>
  39 #include <pwd.h>
  40 #include <signal.h>
  41 #include <stddef.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44 #include <unistd.h>
  45
  46 #include "auth.h"
  47 #include "common.h"
  48 #include "dev.h"
  49 #include "dhcpcd.h"
  50 #include "dhcp6.h"
  51 #include "eloop.h"
  52 #include "if.h"
  53 #include "ipv6nd.h"
  54 #include "logerr.h"
  55 #include "privsep.h"
  56 #include "sa.h"
  57 #include "script.h"
  58
  59 __CTASSERT(sizeof(ioctl_request_t) <= sizeof(unsigned long));
  60
  61 struct psr_error
  62 {
  63         ssize_t psr_result;
  64         int psr_errno;
  65         char psr_pad[sizeof(ssize_t) - sizeof(int)];
  66         size_t psr_datalen;
  67 };
  68
  69 struct psr_ctx {
  70         struct dhcpcd_ctx *psr_ctx;
  71         struct psr_error psr_error;
  72         size_t psr_datalen;
  73         void *psr_data;
  74 };
  75
  76 static void
  77 ps_root_readerrorcb(void *arg)
  78 {
  79         struct psr_ctx *psr_ctx = arg;
  80         struct dhcpcd_ctx *ctx = psr_ctx->psr_ctx;
  81         struct psr_error *psr_error = &psr_ctx->psr_error;
  82         struct iovec iov[] = {
  83                 { .iov_base = psr_error, .iov_len = sizeof(*psr_error) },
  84                 { .iov_base = psr_ctx->psr_data,
  85                   .iov_len = psr_ctx->psr_datalen },
  86         };
  87         ssize_t len;
  88         int exit_code = EXIT_FAILURE;
  89
  90 #define PSR_ERROR(e)                            \
  91         do {                                    \
  92                 psr_error->psr_result = -1;     \
  93                 psr_error->psr_errno = (e);     \
  94                 goto out;                       \
  95         } while (0 /* CONSTCOND */)
  96
  97         len = readv(ctx->ps_root_fd, iov, __arraycount(iov));
  98         if (len == -1)
  99                 PSR_ERROR(errno);
 100         else if ((size_t)len < sizeof(*psr_error))
 101                 PSR_ERROR(EINVAL);
 102         exit_code = EXIT_SUCCESS;
 103
 104 out:
 105         eloop_exit(ctx->ps_eloop, exit_code);
 106 }
 107
 108 ssize_t
 109 ps_root_readerror(struct dhcpcd_ctx *ctx, void *data, size_t len)
 110 {
 111         struct psr_ctx psr_ctx = {
 112             .psr_ctx = ctx,
 113             .psr_data = data, .psr_datalen = len,
 114         };
 115
 116         if (eloop_event_add(ctx->ps_eloop, ctx->ps_root_fd,
 117             ps_root_readerrorcb, &psr_ctx) == -1)
 118                 return -1;
 119
 120         eloop_enter(ctx->ps_eloop);
 121         eloop_start(ctx->ps_eloop, &ctx->sigset);
 122
 123         errno = psr_ctx.psr_error.psr_errno;
 124         return psr_ctx.psr_error.psr_result;
 125 }
 126
 127 #ifdef PRIVSEP_GETIFADDRS
 128 static void
 129 ps_root_mreaderrorcb(void *arg)
 130 {
 131         struct psr_ctx *psr_ctx = arg;
 132         struct dhcpcd_ctx *ctx = psr_ctx->psr_ctx;
 133         struct psr_error *psr_error = &psr_ctx->psr_error;
 134         struct iovec iov[] = {
 135                 { .iov_base = psr_error, .iov_len = sizeof(*psr_error) },
 136                 { .iov_base = NULL, .iov_len = 0 },
 137         };
 138         ssize_t len;
 139         int exit_code = EXIT_FAILURE;
 140
 141         len = recv(ctx->ps_root_fd, psr_error, sizeof(*psr_error), MSG_PEEK);
 142         if (len == -1)
 143                 PSR_ERROR(errno);
 144         else if ((size_t)len < sizeof(*psr_error))
 145                 PSR_ERROR(EINVAL);
 146
 147         if (psr_error->psr_datalen > SSIZE_MAX)
 148                 PSR_ERROR(ENOBUFS);
 149         else if (psr_error->psr_datalen != 0) {
 150                 psr_ctx->psr_data = malloc(psr_error->psr_datalen);
 151                 if (psr_ctx->psr_data == NULL)
 152                         PSR_ERROR(errno);
 153                 psr_ctx->psr_datalen = psr_error->psr_datalen;
 154                 iov[1].iov_base = psr_ctx->psr_data;
 155                 iov[1].iov_len = psr_ctx->psr_datalen;
 156         }
 157
 158         len = readv(ctx->ps_root_fd, iov, __arraycount(iov));
 159         if (len == -1)
 160                 PSR_ERROR(errno);
 161         else if ((size_t)len != sizeof(*psr_error) + psr_ctx->psr_datalen)
 162                 PSR_ERROR(EINVAL);
 163         exit_code = EXIT_SUCCESS;
 164
 165 out:
 166         eloop_exit(ctx->ps_eloop, exit_code);
 167 }
 168
 169 ssize_t
 170 ps_root_mreaderror(struct dhcpcd_ctx *ctx, void **data, size_t *len)
 171 {
 172         struct psr_ctx psr_ctx = {
 173             .psr_ctx = ctx,
 174         };
 175
 176         if (eloop_event_add(ctx->ps_eloop, ctx->ps_root_fd,
 177             ps_root_mreaderrorcb, &psr_ctx) == -1)
 178                 return -1;
 179
 180         eloop_enter(ctx->ps_eloop);
 181         eloop_start(ctx->ps_eloop, &ctx->sigset);
 182
 183         errno = psr_ctx.psr_error.psr_errno;
 184         *data = psr_ctx.psr_data;
 185         *len = psr_ctx.psr_datalen;
 186         return psr_ctx.psr_error.psr_result;
 187 }
 188 #endif
 189
 190 static ssize_t
 191 ps_root_writeerror(struct dhcpcd_ctx *ctx, ssize_t result,
 192     void *data, size_t len)
 193 {
 194         struct psr_error psr = {
 195                 .psr_result = result,
 196                 .psr_errno = errno,
 197                 .psr_datalen = len,
 198         };
 199         struct iovec iov[] = {
 200                 { .iov_base = &psr, .iov_len = sizeof(psr) },
 201                 { .iov_base = data, .iov_len = len },
 202         };
 203
 204 #ifdef PRIVSEP_DEBUG
 205         logdebugx("%s: result %zd errno %d", __func__, result, errno);
 206 #endif
 207
 208         return writev(ctx->ps_root_fd, iov, __arraycount(iov));
 209 }
 210
 211 static ssize_t
 212 ps_root_doioctl(unsigned long req, void *data, size_t len)
 213 {
 214         int s, err;
 215
 216         /* Only allow these ioctls */
 217         switch(req) {
 218 #ifdef SIOCAIFADDR
 219         case SIOCAIFADDR:       /* FALLTHROUGH */
 220         case SIOCDIFADDR:       /* FALLTHROUGH */
 221 #endif
 222 #ifdef SIOCSIFHWADDR
 223         case SIOCSIFHWADDR:     /* FALLTHROUGH */
 224 #endif
 225 #ifdef SIOCGIFPRIORITY
 226         case SIOCGIFPRIORITY:   /* FALLTHROUGH */
 227 #endif
 228         case SIOCSIFFLAGS:      /* FALLTHROUGH */
 229         case SIOCGIFMTU:        /* FALLTHROUGH */
 230         case SIOCSIFMTU:
 231                 break;
 232         default:
 233                 errno = EPERM;
 234                 return -1;
 235         }
 236
 237         s = socket(PF_INET, SOCK_DGRAM, 0);
 238         if (s != -1)
 239 #ifdef IOCTL_REQUEST_TYPE
 240         {
 241                 ioctl_request_t reqt;
 242
 243                 memcpy(&reqt, &req, sizeof(reqt));
 244                 err = ioctl(s, reqt, data, len);
 245         }
 246 #else
 247                 err = ioctl(s, req, data, len);
 248 #endif
 249         else
 250                 err = -1;
 251         if (s != -1)
 252                 close(s);
 253         return err;
 254 }
 255
 256 static ssize_t
 257 ps_root_run_script(struct dhcpcd_ctx *ctx, const void *data, size_t len)
 258 {
 259         const char *envbuf = data;
 260         char * const argv[] = { ctx->script, NULL };
 261         pid_t pid;
 262         int status;
 263
 264         if (len == 0)
 265                 return 0;
 266
 267         if (script_buftoenv(ctx, UNCONST(envbuf), len) == NULL)
 268                 return -1;
 269
 270         pid = script_exec(argv, ctx->script_env);
 271         if (pid == -1)
 272                 return -1;
 273         /* Wait for the script to finish */
 274         while (waitpid(pid, &status, 0) == -1) {
 275                 if (errno != EINTR) {
 276                         logerr(__func__);
 277                         status = 0;
 278                         break;
 279                 }
 280         }
 281         return status;
 282 }
 283
 284 static bool
 285 ps_root_validpath(const struct dhcpcd_ctx *ctx, uint16_t cmd, const char *path)
 286 {
 287
 288         /* Avoid a previous directory attack to avoid /proc/../
 289          * dhcpcd should never use a path with double dots. */
 290         if (strstr(path, "..") != NULL)
 291                 return false;
 292
 293         if (cmd == PS_READFILE) {
 294 #ifdef EMBEDDED_CONFIG
 295                 if (strcmp(ctx->cffile, EMBEDDED_CONFIG) == 0)
 296                         return true;
 297 #endif
 298                 if (strcmp(ctx->cffile, path) == 0)
 299                         return true;
 300         }
 301         if (strncmp(DBDIR, path, strlen(DBDIR)) == 0)
 302                 return true;
 303         if (strncmp(RUNDIR, path, strlen(RUNDIR)) == 0)
 304                 return true;
 305
 306 #ifdef __linux__
 307         if (strncmp("/proc/net/", path, strlen("/proc/net/")) == 0 ||
 308             strncmp("/proc/sys/net/", path, strlen("/proc/sys/net/")) == 0 ||
 309             strncmp("/sys/class/net/", path, strlen("/sys/class/net/")) == 0)
 310                 return true;
 311 #endif
 312
 313         errno = EPERM;
 314         return false;
 315 }
 316
 317 static ssize_t
 318 ps_root_dowritefile(const struct dhcpcd_ctx *ctx,
 319     mode_t mode, void *data, size_t len)
 320 {
 321         char *file = data, *nc;
 322
 323         nc = memchr(file, '\0', len);
 324         if (nc == NULL) {
 325                 errno = EINVAL;
 326                 return -1;
 327         }
 328
 329         if (!ps_root_validpath(ctx, PS_WRITEFILE, file))
 330                 return -1;
 331         nc++;
 332         return writefile(file, mode, nc, len - (size_t)(nc - file));
 333 }
 334
 335 #ifdef AUTH
 336 static ssize_t
 337 ps_root_monordm(uint64_t *rdm, size_t len)
 338 {
 339
 340         if (len != sizeof(*rdm)) {
 341                 errno = EINVAL;
 342                 return -1;
 343         }
 344         return auth_get_rdm_monotonic(rdm);
 345 }
 346 #endif
 347
 348 #ifdef PRIVSEP_GETIFADDRS
 349 #define IFA_NADDRS      3
 350 static ssize_t
 351 ps_root_dogetifaddrs(void **rdata, size_t *rlen)
 352 {
 353         struct ifaddrs *ifaddrs, *ifa, *ifa_next;
 354         size_t len;
 355         uint8_t *buf, *sap;
 356         socklen_t salen;
 357         void *ifa_data;
 358
 359         if (getifaddrs(&ifaddrs) == -1)
 360                 return -1;
 361         if (ifaddrs == NULL) {
 362                 *rdata = NULL;
 363                 *rlen = 0;
 364                 return 0;
 365         }
 366
 367         /* Work out the buffer length required.
 368          * Ensure everything is aligned correctly, which does
 369          * create a larger buffer than what is needed to send,
 370          * but makes creating the same structure in the client
 371          * much easier. */
 372         len = 0;
 373         for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
 374                 len += ALIGN(sizeof(*ifa));
 375                 len += ALIGN(IFNAMSIZ);
 376                 len += ALIGN(sizeof(salen) * IFA_NADDRS);
 377                 if (ifa->ifa_addr != NULL)
 378                         len += ALIGN(sa_len(ifa->ifa_addr));
 379                 if (ifa->ifa_netmask != NULL)
 380                         len += ALIGN(sa_len(ifa->ifa_netmask));
 381                 if (ifa->ifa_broadaddr != NULL)
 382                         len += ALIGN(sa_len(ifa->ifa_broadaddr));
 383         }
 384
 385         /* Use calloc to set everything to zero.
 386          * This satisfies memory sanitizers because don't write
 387          * where we don't need to. */
 388         buf = calloc(1, len);
 389         if (buf == NULL) {
 390                 freeifaddrs(ifaddrs);
 391                 return -1;
 392         }
 393         *rdata = buf;
 394         *rlen = len;
 395
 396         for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
 397                 /* Don't carry ifa_data or ifa_next. */
 398                 ifa_data = ifa->ifa_data;
 399                 ifa_next = ifa->ifa_next;
 400                 ifa->ifa_data = NULL;
 401                 ifa->ifa_next = NULL;
 402                 memcpy(buf, ifa, sizeof(*ifa));
 403                 buf += ALIGN(sizeof(*ifa));
 404                 ifa->ifa_data = ifa_data;
 405                 ifa->ifa_next = ifa_next;
 406
 407                 strlcpy((char *)buf, ifa->ifa_name, IFNAMSIZ);
 408                 buf += ALIGN(IFNAMSIZ);
 409                 sap = buf;
 410                 buf += ALIGN(sizeof(salen) * IFA_NADDRS);
 411
 412 #define COPYINSA(addr)                                          \
 413         do {                                                    \
 414                 salen = sa_len((addr));                         \
 415                 if (salen != 0) {                               \
 416                         memcpy(sap, &salen, sizeof(salen));     \
 417                         memcpy(buf, (addr), salen);             \
 418                         buf += ALIGN(salen);                    \
 419                 }                                               \
 420                 sap += sizeof(salen);                           \
 421         } while (0 /*CONSTCOND */)
 422
 423                 if (ifa->ifa_addr != NULL)
 424                         COPYINSA(ifa->ifa_addr);
 425                 if (ifa->ifa_netmask != NULL)
 426                         COPYINSA(ifa->ifa_netmask);
 427                 if (ifa->ifa_broadaddr != NULL)
 428                         COPYINSA(ifa->ifa_broadaddr);
 429         }
 430
 431         freeifaddrs(ifaddrs);
 432         return 0;
 433 }
 434 #endif
 435
 436 static ssize_t
 437 ps_root_recvmsgcb(void *arg, struct ps_msghdr *psm, struct msghdr *msg)
 438 {
 439         struct dhcpcd_ctx *ctx = arg;
 440         uint16_t cmd;
 441         struct ps_process *psp;
 442         struct iovec *iov = msg->msg_iov;
 443         void *data = iov->iov_base, *rdata = NULL;
 444         size_t len = iov->iov_len, rlen = 0;
 445         uint8_t buf[PS_BUFLEN];
 446         time_t mtime;
 447         ssize_t err;
 448         bool free_rdata = false;
 449
 450         cmd = (uint16_t)(psm->ps_cmd & ~(PS_START | PS_STOP));
 451         psp = ps_findprocess(ctx, &psm->ps_id);
 452
 453 #ifdef PRIVSEP_DEBUG
 454         logerrx("%s: IN cmd %x, psp %p", __func__, psm->ps_cmd, psp);
 455 #endif
 456
 457         if (psp != NULL) {
 458                 if (psm->ps_cmd & PS_STOP) {
 459                         int ret = ps_dostop(ctx, &psp->psp_pid, &psp->psp_fd);
 460
 461                         ps_freeprocess(psp);
 462                         return ret;
 463                 } else if (psm->ps_cmd & PS_START) {
 464                         /* Process has already started .... */
 465                         return 0;
 466                 }
 467
 468                 err = ps_sendpsmmsg(ctx, psp->psp_fd, psm, msg);
 469                 if (err == -1) {
 470                         logerr("%s: failed to send message to pid %d",
 471                             __func__, psp->psp_pid);
 472                         shutdown(psp->psp_fd, SHUT_RDWR);
 473                         close(psp->psp_fd);
 474                         psp->psp_fd = -1;
 475                         ps_freeprocess(psp);
 476                 }
 477                 return 0;
 478         }
 479
 480         if (psm->ps_cmd & PS_STOP && psp == NULL)
 481                 return 0;
 482
 483         switch (cmd) {
 484 #ifdef INET
 485 #ifdef ARP
 486         case PS_BPF_ARP:        /* FALLTHROUGH */
 487 #endif
 488         case PS_BPF_BOOTP:
 489                 return ps_bpf_cmd(ctx, psm, msg);
 490 #endif
 491 #ifdef INET
 492         case PS_BOOTP:
 493                 return ps_inet_cmd(ctx, psm, msg);
 494 #endif
 495 #ifdef INET6
 496 #ifdef DHCP6
 497         case PS_DHCP6:  /* FALLTHROUGH */
 498 #endif
 499         case PS_ND:
 500                 return ps_inet_cmd(ctx, psm, msg);
 501 #endif
 502         default:
 503                 break;
 504         }
 505
 506         assert(msg->msg_iovlen == 0 || msg->msg_iovlen == 1);
 507
 508         /* Reset errno */
 509         errno = 0;
 510
 511         switch (psm->ps_cmd) {
 512         case PS_IOCTL:
 513                 err = ps_root_doioctl(psm->ps_flags, data, len);
 514                 if (err != -1) {
 515                         rdata = data;
 516                         rlen = len;
 517                 }
 518                 break;
 519         case PS_SCRIPT:
 520                 err = ps_root_run_script(ctx, data, len);
 521                 break;
 522         case PS_UNLINK:
 523                 if (!ps_root_validpath(ctx, psm->ps_cmd, data)) {
 524                         err = -1;
 525                         break;
 526                 }
 527                 err = unlink(data);
 528                 break;
 529         case PS_READFILE:
 530                 if (!ps_root_validpath(ctx, psm->ps_cmd, data)) {
 531                         err = -1;
 532                         break;
 533                 }
 534                 err = readfile(data, buf, sizeof(buf));
 535                 if (err != -1) {
 536                         rdata = buf;
 537                         rlen = (size_t)err;
 538                 }
 539                 break;
 540         case PS_WRITEFILE:
 541                 err = ps_root_dowritefile(ctx, (mode_t)psm->ps_flags,
 542                     data, len);
 543                 break;
 544         case PS_FILEMTIME:
 545                 err = filemtime(data, &mtime);
 546                 if (err != -1) {
 547                         rdata = &mtime;
 548                         rlen = sizeof(mtime);
 549                 }
 550                 break;
 551 #ifdef AUTH
 552         case PS_AUTH_MONORDM:
 553                 err = ps_root_monordm(data, len);
 554                 if (err != -1) {
 555                         rdata = data;
 556                         rlen = len;
 557                 }
 558                 break;
 559 #endif
 560 #ifdef PRIVSEP_GETIFADDRS
 561         case PS_GETIFADDRS:
 562                 err = ps_root_dogetifaddrs(&rdata, &rlen);
 563                 free_rdata = true;
 564                 break;
 565 #endif
 566 #if defined(INET6) && (defined(__linux__) || defined(HAVE_PLEDGE))
 567         case PS_IP6FORWARDING:
 568                  err = ip6_forwarding(data);
 569                  break;
 570 #endif
 571 #ifdef PLUGIN_DEV
 572         case PS_DEV_INITTED:
 573                 err = dev_initialized(ctx, data);
 574                 break;
 575         case PS_DEV_LISTENING:
 576                 err = dev_listening(ctx);
 577                 break;
 578 #endif
 579         default:
 580                 err = ps_root_os(psm, msg, &rdata, &rlen);
 581                 break;
 582         }
 583
 584         err = ps_root_writeerror(ctx, err, rlen != 0 ? rdata : 0, rlen);
 585         if (free_rdata)
 586                 free(rdata);
 587         return err;
 588 }
 589
 590 /* Receive from state engine, do an action. */
 591 static void
 592 ps_root_recvmsg(void *arg)
 593 {
 594         struct dhcpcd_ctx *ctx = arg;
 595
 596         if (ps_recvpsmsg(ctx, ctx->ps_root_fd, ps_root_recvmsgcb, ctx) == -1)
 597                 logerr(__func__);
 598 }
 599
 600 #ifdef PLUGIN_DEV
 601 static int
 602 ps_root_handleinterface(void *arg, int action, const char *ifname)
 603 {
 604         struct dhcpcd_ctx *ctx = arg;
 605         unsigned long flag;
 606
 607         if (action == 1)
 608                 flag = PS_DEV_IFADDED;
 609         else if (action == -1)
 610                 flag = PS_DEV_IFREMOVED;
 611         else if (action == 0)
 612                 flag = PS_DEV_IFUPDATED;
 613         else {
 614                 errno = EINVAL;
 615                 return -1;
 616         }
 617
 618         return (int)ps_sendcmd(ctx, ctx->ps_data_fd, PS_DEV_IFCMD, flag,
 619             ifname, strlen(ifname) + 1);
 620 }
 621 #endif
 622
 623 static int
 624 ps_root_startcb(void *arg)
 625 {
 626         struct dhcpcd_ctx *ctx = arg;
 627
 628         if (ctx->options & DHCPCD_MASTER)
 629                 setproctitle("[privileged actioneer]");
 630         else
 631                 setproctitle("[privileged actioneer] %s%s%s",
 632                     ctx->ifv[0],
 633                     ctx->options & DHCPCD_IPV4 ? " [ip4]" : "",
 634                     ctx->options & DHCPCD_IPV6 ? " [ip6]" : "");
 635         ctx->ps_root_pid = getpid();
 636         ctx->options |= DHCPCD_PRIVSEPROOT;
 637
 638         /* Open network sockets for sending.
 639          * This is a small bit wasteful for non sandboxed OS's
 640          * but makes life very easy for unicasting DHCPv6 in non master
 641          * mode as we no longer care about address selection.
 642          * We can't call shutdown SHUT_RD on the socket because it's
 643          * not connectd. All we can do is try and set a zero sized
 644          * receive buffer and just let it overflow.
 645          * Reading from it just to drain it is a waste of CPU time. */
 646 #ifdef INET
 647         if (ctx->options & DHCPCD_IPV4) {
 648                 int buflen = 1;
 649
 650                 ctx->udp_wfd = xsocket(PF_INET,
 651                     SOCK_RAW | SOCK_CXNB, IPPROTO_UDP);
 652                 if (ctx->udp_wfd == -1)
 653                         logerr("%s: dhcp_openraw", __func__);
 654                 else if (setsockopt(ctx->udp_wfd, SOL_SOCKET, SO_RCVBUF,
 655                     &buflen, sizeof(buflen)) == -1)
 656                         logerr("%s: setsockopt SO_RCVBUF DHCP", __func__);
 657         }
 658 #endif
 659 #ifdef INET6
 660         if (ctx->options & DHCPCD_IPV6) {
 661                 int buflen = 1;
 662
 663                 ctx->nd_fd = ipv6nd_open(false);
 664                 if (ctx->nd_fd == -1)
 665                         logerr("%s: ipv6nd_open", __func__);
 666                 else if (setsockopt(ctx->nd_fd, SOL_SOCKET, SO_RCVBUF,
 667                     &buflen, sizeof(buflen)) == -1)
 668                         logerr("%s: setsockopt SO_RCVBUF ND", __func__);
 669         }
 670 #endif
 671 #ifdef DHCP6
 672         if (ctx->options & DHCPCD_IPV6) {
 673                 int buflen = 1;
 674
 675                 ctx->dhcp6_wfd = dhcp6_openraw();
 676                 if (ctx->dhcp6_wfd == -1)
 677                         logerr("%s: dhcp6_openraw", __func__);
 678                 else if (setsockopt(ctx->dhcp6_wfd, SOL_SOCKET, SO_RCVBUF,
 679                     &buflen, sizeof(buflen)) == -1)
 680                         logerr("%s: setsockopt SO_RCVBUF DHCP6", __func__);
 681         }
 682 #endif
 683
 684 #ifdef PLUGIN_DEV
 685         /* Start any dev listening plugin which may want to
 686          * change the interface name provided by the kernel */
 687         if ((ctx->options & (DHCPCD_MASTER | DHCPCD_DEV)) ==
 688             (DHCPCD_MASTER | DHCPCD_DEV))
 689                 dev_start(ctx, ps_root_handleinterface);
 690 #endif
 691
 692         return 0;
 693 }
 694
 695 static void
 696 ps_root_signalcb(int sig, __unused void *arg)
 697 {
 698
 699         if (sig == SIGCHLD) {
 700                 while (waitpid(-1, NULL, WNOHANG) > 0)
 701                         ;
 702                 return;
 703         }
 704 }
 705
 706 int (*handle_interface)(void *, int, const char *);
 707
 708 #ifdef PLUGIN_DEV
 709 static ssize_t
 710 ps_root_devcb(struct dhcpcd_ctx *ctx, struct ps_msghdr *psm, struct msghdr *msg)
 711 {
 712         int action;
 713         struct iovec *iov = msg->msg_iov;
 714
 715         if (msg->msg_iovlen != 1) {
 716                 errno = EINVAL;
 717                 return -1;
 718         }
 719
 720         switch(psm->ps_flags) {
 721         case PS_DEV_IFADDED:
 722                 action = 1;
 723                 break;
 724         case PS_DEV_IFREMOVED:
 725                 action = -1;
 726                 break;
 727         case PS_DEV_IFUPDATED:
 728                 action = 0;
 729                 break;
 730         default:
 731                 errno = EINVAL;
 732                 return -1;
 733         }
 734
 735         return dhcpcd_handleinterface(ctx, action, iov->iov_base);
 736 }
 737 #endif
 738
 739 static ssize_t
 740 ps_root_dispatchcb(void *arg, struct ps_msghdr *psm, struct msghdr *msg)
 741 {
 742         struct dhcpcd_ctx *ctx = arg;
 743         ssize_t err;
 744
 745         switch(psm->ps_cmd) {
 746 #ifdef PLUGIN_DEV
 747         case PS_DEV_IFCMD:
 748                 err = ps_root_devcb(ctx, psm, msg);
 749                 break;
 750 #endif
 751         default:
 752 #ifdef INET
 753                 err = ps_bpf_dispatch(ctx, psm, msg);
 754                 if (err == -1 && errno == ENOTSUP)
 755 #endif
 756                         err = ps_inet_dispatch(ctx, psm, msg);
 757         }
 758         return err;
 759 }
 760
 761 static void
 762 ps_root_dispatch(void *arg)
 763 {
 764         struct dhcpcd_ctx *ctx = arg;
 765
 766         if (ps_recvpsmsg(ctx, ctx->ps_data_fd, ps_root_dispatchcb, ctx) == -1)
 767                 logerr(__func__);
 768 }
 769
 770 pid_t
 771 ps_root_start(struct dhcpcd_ctx *ctx)
 772 {
 773         int fd[2];
 774         pid_t pid;
 775
 776         if (socketpair(AF_UNIX, SOCK_DGRAM | SOCK_CXNB, 0, fd) == -1)
 777                 return -1;
 778         if (ps_setbuf_fdpair(fd) == -1)
 779                 return -1;
 780 #ifdef PRIVSEP_RIGHTS
 781         if (ps_rights_limit_fdpair(fd) == -1)
 782                 return -1;
 783 #endif
 784
 785         pid = ps_dostart(ctx, &ctx->ps_root_pid, &ctx->ps_root_fd,
 786             ps_root_recvmsg, NULL, ctx,
 787             ps_root_startcb, ps_root_signalcb, 0);
 788
 789         if (pid == 0) {
 790                 ctx->ps_data_fd = fd[1];
 791                 close(fd[0]);
 792                 return 0;
 793         } else if (pid == -1)
 794                 return -1;
 795
 796         ctx->ps_data_fd = fd[0];
 797         close(fd[1]);
 798         if (eloop_event_add(ctx->eloop, ctx->ps_data_fd,
 799             ps_root_dispatch, ctx) == -1)
 800                 return -1;
 801
 802         if ((ctx->ps_eloop = eloop_new()) == NULL)
 803                 return -1;
 804
 805         eloop_signal_set_cb(ctx->ps_eloop,
 806             dhcpcd_signals, dhcpcd_signals_len,
 807             ps_root_signalcb, ctx);
 808
 809         return pid;
 810 }
 811
 812 int
 813 ps_root_stop(struct dhcpcd_ctx *ctx)
 814 {
 815
 816         return ps_dostop(ctx, &ctx->ps_root_pid, &ctx->ps_root_fd);
 817 }
 818
 819 ssize_t
 820 ps_root_script(struct dhcpcd_ctx *ctx, const void *data, size_t len)
 821 {
 822
 823         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_SCRIPT, 0, data, len) == -1)
 824                 return -1;
 825         return ps_root_readerror(ctx, NULL, 0);
 826 }
 827
 828 ssize_t
 829 ps_root_ioctl(struct dhcpcd_ctx *ctx, ioctl_request_t req, void *data,
 830     size_t len)
 831 {
 832 #ifdef IOCTL_REQUEST_TYPE
 833         unsigned long ulreq = 0;
 834
 835         memcpy(&ulreq, &req, sizeof(req));
 836         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_IOCTL, ulreq, data, len) == -1)
 837                 return -1;
 838 #else
 839         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_IOCTL, req, data, len) == -1)
 840                 return -1;
 841 #endif
 842         return ps_root_readerror(ctx, data, len);
 843 }
 844
 845 ssize_t
 846 ps_root_unlink(struct dhcpcd_ctx *ctx, const char *file)
 847 {
 848
 849         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_UNLINK, 0,
 850             file, strlen(file) + 1) == -1)
 851                 return -1;
 852         return ps_root_readerror(ctx, NULL, 0);
 853 }
 854
 855 ssize_t
 856 ps_root_readfile(struct dhcpcd_ctx *ctx, const char *file,
 857     void *data, size_t len)
 858 {
 859         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_READFILE, 0,
 860             file, strlen(file) + 1) == -1)
 861                 return -1;
 862         return ps_root_readerror(ctx, data, len);
 863 }
 864
 865 ssize_t
 866 ps_root_writefile(struct dhcpcd_ctx *ctx, const char *file, mode_t mode,
 867     const void *data, size_t len)
 868 {
 869         char buf[PS_BUFLEN];
 870         size_t flen;
 871
 872         flen = strlcpy(buf, file, sizeof(buf));
 873         flen += 1;
 874         if (flen > sizeof(buf) || flen + len > sizeof(buf)) {
 875                 errno = ENOBUFS;
 876                 return -1;
 877         }
 878         memcpy(buf + flen, data, len);
 879
 880         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_WRITEFILE, mode,
 881             buf, flen + len) == -1)
 882                 return -1;
 883         return ps_root_readerror(ctx, NULL, 0);
 884 }
 885
 886 ssize_t
 887 ps_root_filemtime(struct dhcpcd_ctx *ctx, const char *file, time_t *time)
 888 {
 889
 890         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_FILEMTIME, 0,
 891             file, strlen(file) + 1) == -1)
 892                 return -1;
 893         return ps_root_readerror(ctx, time, sizeof(*time));
 894 }
 895
 896 #ifdef PRIVSEP_GETIFADDRS
 897 int
 898 ps_root_getifaddrs(struct dhcpcd_ctx *ctx, struct ifaddrs **ifahead)
 899 {
 900         struct ifaddrs *ifa;
 901         void *buf = NULL;
 902         char *bp, *sap;
 903         socklen_t salen;
 904         size_t len;
 905         ssize_t err;
 906
 907         if (ps_sendcmd(ctx, ctx->ps_root_fd,
 908             PS_GETIFADDRS, 0, NULL, 0) == -1)
 909                 return -1;
 910         err = ps_root_mreaderror(ctx, &buf, &len);
 911
 912         if (err == -1)
 913                 return -1;
 914
 915         /* Should be impossible - lo0 will always exist. */
 916         if (len == 0) {
 917                 *ifahead = NULL;
 918                 return 0;
 919         }
 920
 921         bp = buf;
 922         *ifahead = (struct ifaddrs *)(void *)bp;
 923         for (ifa = *ifahead; ifa != NULL; ifa = ifa->ifa_next) {
 924                 if (len < ALIGN(sizeof(*ifa)) +
 925                     ALIGN(IFNAMSIZ) + ALIGN(sizeof(salen) * IFA_NADDRS))
 926                         goto err;
 927                 bp += ALIGN(sizeof(*ifa));
 928                 ifa->ifa_name = bp;
 929                 bp += ALIGN(IFNAMSIZ);
 930                 sap = bp;
 931                 bp += ALIGN(sizeof(salen) * IFA_NADDRS);
 932                 len -= ALIGN(sizeof(*ifa)) +
 933                     ALIGN(IFNAMSIZ) + ALIGN(sizeof(salen) * IFA_NADDRS);
 934
 935 #define COPYOUTSA(addr)                                         \
 936         do {                                                    \
 937                 memcpy(&salen, sap, sizeof(salen));             \
 938                 if (len < salen)                                \
 939                         goto err;                               \
 940                 if (salen != 0) {                               \
 941                         (addr) = (struct sockaddr *)bp;         \
 942                         bp += ALIGN(salen);                     \
 943                         len -= ALIGN(salen);                    \
 944                 }                                               \
 945                 sap += sizeof(salen);                           \
 946         } while (0 /* CONSTCOND */)
 947
 948                 COPYOUTSA(ifa->ifa_addr);
 949                 COPYOUTSA(ifa->ifa_netmask);
 950                 COPYOUTSA(ifa->ifa_broadaddr);
 951                 if (len != 0)
 952                         ifa->ifa_next = (struct ifaddrs *)(void *)bp;
 953                 else
 954                         ifa->ifa_next = NULL;
 955         }
 956         return 0;
 957
 958 err:
 959         free(buf);
 960         *ifahead = NULL;
 961         errno = EINVAL;
 962         return -1;
 963 }
 964 #endif
 965
 966 #if defined(__linux__) || defined(HAVE_PLEDGE)
 967 ssize_t
 968 ps_root_ip6forwarding(struct dhcpcd_ctx *ctx, const char *ifname)
 969 {
 970
 971         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_IP6FORWARDING, 0,
 972             ifname, ifname != NULL ? strlen(ifname) + 1 : 0) == -1)
 973                 return -1;
 974         return ps_root_readerror(ctx, NULL, 0);
 975 }
 976 #endif
 977
 978 #ifdef AUTH
 979 int
 980 ps_root_getauthrdm(struct dhcpcd_ctx *ctx, uint64_t *rdm)
 981 {
 982
 983         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_AUTH_MONORDM, 0,
 984             rdm, sizeof(*rdm))== -1)
 985                 return -1;
 986         return (int)ps_root_readerror(ctx, rdm, sizeof(*rdm));
 987 }
 988 #endif
 989
 990 #ifdef PLUGIN_DEV
 991 int
 992 ps_root_dev_initialized(struct dhcpcd_ctx *ctx, const char *ifname)
 993 {
 994
 995         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_DEV_INITTED, 0,
 996             ifname, strlen(ifname) + 1)== -1)
 997                 return -1;
 998         return (int)ps_root_readerror(ctx, NULL, 0);
 999 }
1000
1001 int
1002 ps_root_dev_listening(struct dhcpcd_ctx * ctx)
1003 {
1004
1005         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_DEV_LISTENING, 0, NULL, 0)== -1)
1006                 return -1;
1007         return (int)ps_root_readerror(ctx, NULL, 0);
1008 }
1009 #endif