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      4
 350 static ssize_t
 351 ps_root_dogetifaddrs(void **rdata, size_t *rlen)
 352 {
 353         struct ifaddrs *ifaddrs, *ifa;
 354         size_t len;
 355         uint8_t *buf, *sap;
 356         socklen_t salen;
 357
 358         if (getifaddrs(&ifaddrs) == -1)
 359                 return -1;
 360         if (ifaddrs == NULL) {
 361                 *rdata = NULL;
 362                 *rlen = 0;
 363                 return 0;
 364         }
 365
 366         /* Work out the buffer length required.
 367          * Ensure everything is aligned correctly, which does
 368          * create a larger buffer than what is needed to send,
 369          * but makes creating the same structure in the client
 370          * much easier. */
 371         len = 0;
 372         for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
 373                 len += ALIGN(sizeof(*ifa));
 374                 len += ALIGN(IFNAMSIZ);
 375                 len += ALIGN(sizeof(salen) * IFA_NADDRS);
 376                 if (ifa->ifa_addr != NULL)
 377                         len += ALIGN(sa_len(ifa->ifa_addr));
 378                 if (ifa->ifa_netmask != NULL)
 379                         len += ALIGN(sa_len(ifa->ifa_netmask));
 380                 if (ifa->ifa_broadaddr != NULL)
 381                         len += ALIGN(sa_len(ifa->ifa_broadaddr));
 382 #ifdef BSD
 383                 /*
 384                  * On BSD we need to carry ifa_data so we can access
 385                  * if_data->ifi_link_state
 386                  */
 387                 if (ifa->ifa_addr != NULL &&
 388                     ifa->ifa_addr->sa_family == AF_LINK)
 389                         len += ALIGN(sizeof(struct if_data));
 390 #endif
 391         }
 392
 393         /* Use calloc to set everything to zero.
 394          * This satisfies memory sanitizers because don't write
 395          * where we don't need to. */
 396         buf = calloc(1, len);
 397         if (buf == NULL) {
 398                 freeifaddrs(ifaddrs);
 399                 return -1;
 400         }
 401         *rdata = buf;
 402         *rlen = len;
 403
 404         for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
 405                 memcpy(buf, ifa, sizeof(*ifa));
 406                 buf += ALIGN(sizeof(*ifa));
 407
 408                 strlcpy((char *)buf, ifa->ifa_name, IFNAMSIZ);
 409                 buf += ALIGN(IFNAMSIZ);
 410                 sap = buf;
 411                 buf += ALIGN(sizeof(salen) * IFA_NADDRS);
 412
 413 #define COPYINSA(addr)                                          \
 414         do {                                                    \
 415                 if ((addr) != NULL)                             \
 416                         salen = sa_len((addr));                 \
 417                 else                                            \
 418                         salen = 0;                              \
 419                 if (salen != 0) {                               \
 420                         memcpy(sap, &salen, sizeof(salen));     \
 421                         memcpy(buf, (addr), salen);             \
 422                         buf += ALIGN(salen);                    \
 423                 }                                               \
 424                 sap += sizeof(salen);                           \
 425         } while (0 /*CONSTCOND */)
 426
 427                 COPYINSA(ifa->ifa_addr);
 428                 COPYINSA(ifa->ifa_netmask);
 429                 COPYINSA(ifa->ifa_broadaddr);
 430
 431 #ifdef BSD
 432                 if (ifa->ifa_addr != NULL &&
 433                     ifa->ifa_addr->sa_family == AF_LINK)
 434                 {
 435                         salen = (socklen_t)sizeof(struct if_data);
 436                         memcpy(buf, ifa->ifa_data, salen);
 437                         buf += ALIGN(salen);
 438                 } else
 439 #endif
 440                         salen = 0;
 441                 memcpy(sap, &salen, sizeof(salen));
 442         }
 443
 444         freeifaddrs(ifaddrs);
 445         return 0;
 446 }
 447 #endif
 448
 449 static ssize_t
 450 ps_root_recvmsgcb(void *arg, struct ps_msghdr *psm, struct msghdr *msg)
 451 {
 452         struct dhcpcd_ctx *ctx = arg;
 453         uint16_t cmd;
 454         struct ps_process *psp;
 455         struct iovec *iov = msg->msg_iov;
 456         void *data = iov->iov_base, *rdata = NULL;
 457         size_t len = iov->iov_len, rlen = 0;
 458         uint8_t buf[PS_BUFLEN];
 459         time_t mtime;
 460         ssize_t err;
 461         bool free_rdata = false;
 462
 463         cmd = (uint16_t)(psm->ps_cmd & ~(PS_START | PS_STOP));
 464         psp = ps_findprocess(ctx, &psm->ps_id);
 465
 466 #ifdef PRIVSEP_DEBUG
 467         logerrx("%s: IN cmd %x, psp %p", __func__, psm->ps_cmd, psp);
 468 #endif
 469
 470         if (psp != NULL) {
 471                 if (psm->ps_cmd & PS_STOP) {
 472                         int ret = ps_dostop(ctx, &psp->psp_pid, &psp->psp_fd);
 473
 474                         ps_freeprocess(psp);
 475                         return ret;
 476                 } else if (psm->ps_cmd & PS_START) {
 477                         /* Process has already started .... */
 478                         return 0;
 479                 }
 480
 481                 err = ps_sendpsmmsg(ctx, psp->psp_fd, psm, msg);
 482                 if (err == -1) {
 483                         logerr("%s: failed to send message to pid %d",
 484                             __func__, psp->psp_pid);
 485                         shutdown(psp->psp_fd, SHUT_RDWR);
 486                         close(psp->psp_fd);
 487                         psp->psp_fd = -1;
 488                         ps_freeprocess(psp);
 489                 }
 490                 return 0;
 491         }
 492
 493         if (psm->ps_cmd & PS_STOP && psp == NULL)
 494                 return 0;
 495
 496         switch (cmd) {
 497 #ifdef INET
 498 #ifdef ARP
 499         case PS_BPF_ARP:        /* FALLTHROUGH */
 500 #endif
 501         case PS_BPF_BOOTP:
 502                 return ps_bpf_cmd(ctx, psm, msg);
 503 #endif
 504 #ifdef INET
 505         case PS_BOOTP:
 506                 return ps_inet_cmd(ctx, psm, msg);
 507 #endif
 508 #ifdef INET6
 509 #ifdef DHCP6
 510         case PS_DHCP6:  /* FALLTHROUGH */
 511 #endif
 512         case PS_ND:
 513                 return ps_inet_cmd(ctx, psm, msg);
 514 #endif
 515         default:
 516                 break;
 517         }
 518
 519         assert(msg->msg_iovlen == 0 || msg->msg_iovlen == 1);
 520
 521         /* Reset errno */
 522         errno = 0;
 523
 524         switch (psm->ps_cmd) {
 525         case PS_IOCTL:
 526                 err = ps_root_doioctl(psm->ps_flags, data, len);
 527                 if (err != -1) {
 528                         rdata = data;
 529                         rlen = len;
 530                 }
 531                 break;
 532         case PS_SCRIPT:
 533                 err = ps_root_run_script(ctx, data, len);
 534                 break;
 535         case PS_UNLINK:
 536                 if (!ps_root_validpath(ctx, psm->ps_cmd, data)) {
 537                         err = -1;
 538                         break;
 539                 }
 540                 err = unlink(data);
 541                 break;
 542         case PS_READFILE:
 543                 if (!ps_root_validpath(ctx, psm->ps_cmd, data)) {
 544                         err = -1;
 545                         break;
 546                 }
 547                 err = readfile(data, buf, sizeof(buf));
 548                 if (err != -1) {
 549                         rdata = buf;
 550                         rlen = (size_t)err;
 551                 }
 552                 break;
 553         case PS_WRITEFILE:
 554                 err = ps_root_dowritefile(ctx, (mode_t)psm->ps_flags,
 555                     data, len);
 556                 break;
 557         case PS_FILEMTIME:
 558                 err = filemtime(data, &mtime);
 559                 if (err != -1) {
 560                         rdata = &mtime;
 561                         rlen = sizeof(mtime);
 562                 }
 563                 break;
 564 #ifdef AUTH
 565         case PS_AUTH_MONORDM:
 566                 err = ps_root_monordm(data, len);
 567                 if (err != -1) {
 568                         rdata = data;
 569                         rlen = len;
 570                 }
 571                 break;
 572 #endif
 573 #ifdef PRIVSEP_GETIFADDRS
 574         case PS_GETIFADDRS:
 575                 err = ps_root_dogetifaddrs(&rdata, &rlen);
 576                 free_rdata = true;
 577                 break;
 578 #endif
 579 #if defined(INET6) && (defined(__linux__) || defined(HAVE_PLEDGE))
 580         case PS_IP6FORWARDING:
 581                  err = ip6_forwarding(data);
 582                  break;
 583 #endif
 584 #ifdef PLUGIN_DEV
 585         case PS_DEV_INITTED:
 586                 err = dev_initialised(ctx, data);
 587                 break;
 588         case PS_DEV_LISTENING:
 589                 err = dev_listening(ctx);
 590                 break;
 591 #endif
 592         default:
 593                 err = ps_root_os(psm, msg, &rdata, &rlen);
 594                 break;
 595         }
 596
 597         err = ps_root_writeerror(ctx, err, rlen != 0 ? rdata : 0, rlen);
 598         if (free_rdata)
 599                 free(rdata);
 600         return err;
 601 }
 602
 603 /* Receive from state engine, do an action. */
 604 static void
 605 ps_root_recvmsg(void *arg)
 606 {
 607         struct dhcpcd_ctx *ctx = arg;
 608
 609         if (ps_recvpsmsg(ctx, ctx->ps_root_fd, ps_root_recvmsgcb, ctx) == -1)
 610                 logerr(__func__);
 611 }
 612
 613 #ifdef PLUGIN_DEV
 614 static int
 615 ps_root_handleinterface(void *arg, int action, const char *ifname)
 616 {
 617         struct dhcpcd_ctx *ctx = arg;
 618         unsigned long flag;
 619
 620         if (action == 1)
 621                 flag = PS_DEV_IFADDED;
 622         else if (action == -1)
 623                 flag = PS_DEV_IFREMOVED;
 624         else if (action == 0)
 625                 flag = PS_DEV_IFUPDATED;
 626         else {
 627                 errno = EINVAL;
 628                 return -1;
 629         }
 630
 631         return (int)ps_sendcmd(ctx, ctx->ps_data_fd, PS_DEV_IFCMD, flag,
 632             ifname, strlen(ifname) + 1);
 633 }
 634 #endif
 635
 636 static int
 637 ps_root_startcb(void *arg)
 638 {
 639         struct dhcpcd_ctx *ctx = arg;
 640
 641         if (ctx->options & DHCPCD_MASTER)
 642                 setproctitle("[privileged actioneer]");
 643         else
 644                 setproctitle("[privileged actioneer] %s%s%s",
 645                     ctx->ifv[0],
 646                     ctx->options & DHCPCD_IPV4 ? " [ip4]" : "",
 647                     ctx->options & DHCPCD_IPV6 ? " [ip6]" : "");
 648         ctx->ps_root_pid = getpid();
 649         ctx->options |= DHCPCD_PRIVSEPROOT;
 650
 651         /* Open network sockets for sending.
 652          * This is a small bit wasteful for non sandboxed OS's
 653          * but makes life very easy for unicasting DHCPv6 in non master
 654          * mode as we no longer care about address selection.
 655          * We can't call shutdown SHUT_RD on the socket because it's
 656          * not connectd. All we can do is try and set a zero sized
 657          * receive buffer and just let it overflow.
 658          * Reading from it just to drain it is a waste of CPU time. */
 659 #ifdef INET
 660         if (ctx->options & DHCPCD_IPV4) {
 661                 int buflen = 1;
 662
 663                 ctx->udp_wfd = xsocket(PF_INET,
 664                     SOCK_RAW | SOCK_CXNB, IPPROTO_UDP);
 665                 if (ctx->udp_wfd == -1)
 666                         logerr("%s: dhcp_openraw", __func__);
 667                 else if (setsockopt(ctx->udp_wfd, SOL_SOCKET, SO_RCVBUF,
 668                     &buflen, sizeof(buflen)) == -1)
 669                         logerr("%s: setsockopt SO_RCVBUF DHCP", __func__);
 670         }
 671 #endif
 672 #ifdef INET6
 673         if (ctx->options & DHCPCD_IPV6) {
 674                 int buflen = 1;
 675
 676                 ctx->nd_fd = ipv6nd_open(false);
 677                 if (ctx->nd_fd == -1)
 678                         logerr("%s: ipv6nd_open", __func__);
 679                 else if (setsockopt(ctx->nd_fd, SOL_SOCKET, SO_RCVBUF,
 680                     &buflen, sizeof(buflen)) == -1)
 681                         logerr("%s: setsockopt SO_RCVBUF ND", __func__);
 682         }
 683 #endif
 684 #ifdef DHCP6
 685         if (ctx->options & DHCPCD_IPV6) {
 686                 int buflen = 1;
 687
 688                 ctx->dhcp6_wfd = dhcp6_openraw();
 689                 if (ctx->dhcp6_wfd == -1)
 690                         logerr("%s: dhcp6_openraw", __func__);
 691                 else if (setsockopt(ctx->dhcp6_wfd, SOL_SOCKET, SO_RCVBUF,
 692                     &buflen, sizeof(buflen)) == -1)
 693                         logerr("%s: setsockopt SO_RCVBUF DHCP6", __func__);
 694         }
 695 #endif
 696
 697 #ifdef PLUGIN_DEV
 698         /* Start any dev listening plugin which may want to
 699          * change the interface name provided by the kernel */
 700         if ((ctx->options & (DHCPCD_MASTER | DHCPCD_DEV)) ==
 701             (DHCPCD_MASTER | DHCPCD_DEV))
 702                 dev_start(ctx, ps_root_handleinterface);
 703 #endif
 704
 705         return 0;
 706 }
 707
 708 static void
 709 ps_root_signalcb(int sig, __unused void *arg)
 710 {
 711
 712         if (sig == SIGCHLD) {
 713                 while (waitpid(-1, NULL, WNOHANG) > 0)
 714                         ;
 715                 return;
 716         }
 717 }
 718
 719 int (*handle_interface)(void *, int, const char *);
 720
 721 #ifdef PLUGIN_DEV
 722 static ssize_t
 723 ps_root_devcb(struct dhcpcd_ctx *ctx, struct ps_msghdr *psm, struct msghdr *msg)
 724 {
 725         int action;
 726         struct iovec *iov = msg->msg_iov;
 727
 728         if (msg->msg_iovlen != 1) {
 729                 errno = EINVAL;
 730                 return -1;
 731         }
 732
 733         switch(psm->ps_flags) {
 734         case PS_DEV_IFADDED:
 735                 action = 1;
 736                 break;
 737         case PS_DEV_IFREMOVED:
 738                 action = -1;
 739                 break;
 740         case PS_DEV_IFUPDATED:
 741                 action = 0;
 742                 break;
 743         default:
 744                 errno = EINVAL;
 745                 return -1;
 746         }
 747
 748         return dhcpcd_handleinterface(ctx, action, iov->iov_base);
 749 }
 750 #endif
 751
 752 static ssize_t
 753 ps_root_dispatchcb(void *arg, struct ps_msghdr *psm, struct msghdr *msg)
 754 {
 755         struct dhcpcd_ctx *ctx = arg;
 756         ssize_t err;
 757
 758         switch(psm->ps_cmd) {
 759 #ifdef PLUGIN_DEV
 760         case PS_DEV_IFCMD:
 761                 err = ps_root_devcb(ctx, psm, msg);
 762                 break;
 763 #endif
 764         default:
 765 #ifdef INET
 766                 err = ps_bpf_dispatch(ctx, psm, msg);
 767                 if (err == -1 && errno == ENOTSUP)
 768 #endif
 769                         err = ps_inet_dispatch(ctx, psm, msg);
 770         }
 771         return err;
 772 }
 773
 774 static void
 775 ps_root_dispatch(void *arg)
 776 {
 777         struct dhcpcd_ctx *ctx = arg;
 778
 779         if (ps_recvpsmsg(ctx, ctx->ps_data_fd, ps_root_dispatchcb, ctx) == -1)
 780                 logerr(__func__);
 781 }
 782
 783 pid_t
 784 ps_root_start(struct dhcpcd_ctx *ctx)
 785 {
 786         int fd[2];
 787         pid_t pid;
 788
 789         if (socketpair(AF_UNIX, SOCK_DGRAM | SOCK_CXNB, 0, fd) == -1)
 790                 return -1;
 791         if (ps_setbuf_fdpair(fd) == -1)
 792                 return -1;
 793 #ifdef PRIVSEP_RIGHTS
 794         if (ps_rights_limit_fdpair(fd) == -1)
 795                 return -1;
 796 #endif
 797
 798         pid = ps_dostart(ctx, &ctx->ps_root_pid, &ctx->ps_root_fd,
 799             ps_root_recvmsg, NULL, ctx,
 800             ps_root_startcb, ps_root_signalcb, 0);
 801
 802         if (pid == 0) {
 803                 ctx->ps_data_fd = fd[1];
 804                 close(fd[0]);
 805                 return 0;
 806         } else if (pid == -1)
 807                 return -1;
 808
 809         ctx->ps_data_fd = fd[0];
 810         close(fd[1]);
 811         if (eloop_event_add(ctx->eloop, ctx->ps_data_fd,
 812             ps_root_dispatch, ctx) == -1)
 813                 return -1;
 814
 815         if ((ctx->ps_eloop = eloop_new()) == NULL)
 816                 return -1;
 817
 818         eloop_signal_set_cb(ctx->ps_eloop,
 819             dhcpcd_signals, dhcpcd_signals_len,
 820             ps_root_signalcb, ctx);
 821
 822         return pid;
 823 }
 824
 825 int
 826 ps_root_stop(struct dhcpcd_ctx *ctx)
 827 {
 828
 829         return ps_dostop(ctx, &ctx->ps_root_pid, &ctx->ps_root_fd);
 830 }
 831
 832 ssize_t
 833 ps_root_script(struct dhcpcd_ctx *ctx, const void *data, size_t len)
 834 {
 835
 836         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_SCRIPT, 0, data, len) == -1)
 837                 return -1;
 838         return ps_root_readerror(ctx, NULL, 0);
 839 }
 840
 841 ssize_t
 842 ps_root_ioctl(struct dhcpcd_ctx *ctx, ioctl_request_t req, void *data,
 843     size_t len)
 844 {
 845 #ifdef IOCTL_REQUEST_TYPE
 846         unsigned long ulreq = 0;
 847
 848         memcpy(&ulreq, &req, sizeof(req));
 849         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_IOCTL, ulreq, data, len) == -1)
 850                 return -1;
 851 #else
 852         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_IOCTL, req, data, len) == -1)
 853                 return -1;
 854 #endif
 855         return ps_root_readerror(ctx, data, len);
 856 }
 857
 858 ssize_t
 859 ps_root_unlink(struct dhcpcd_ctx *ctx, const char *file)
 860 {
 861
 862         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_UNLINK, 0,
 863             file, strlen(file) + 1) == -1)
 864                 return -1;
 865         return ps_root_readerror(ctx, NULL, 0);
 866 }
 867
 868 ssize_t
 869 ps_root_readfile(struct dhcpcd_ctx *ctx, const char *file,
 870     void *data, size_t len)
 871 {
 872         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_READFILE, 0,
 873             file, strlen(file) + 1) == -1)
 874                 return -1;
 875         return ps_root_readerror(ctx, data, len);
 876 }
 877
 878 ssize_t
 879 ps_root_writefile(struct dhcpcd_ctx *ctx, const char *file, mode_t mode,
 880     const void *data, size_t len)
 881 {
 882         char buf[PS_BUFLEN];
 883         size_t flen;
 884
 885         flen = strlcpy(buf, file, sizeof(buf));
 886         flen += 1;
 887         if (flen > sizeof(buf) || flen + len > sizeof(buf)) {
 888                 errno = ENOBUFS;
 889                 return -1;
 890         }
 891         memcpy(buf + flen, data, len);
 892
 893         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_WRITEFILE, mode,
 894             buf, flen + len) == -1)
 895                 return -1;
 896         return ps_root_readerror(ctx, NULL, 0);
 897 }
 898
 899 ssize_t
 900 ps_root_filemtime(struct dhcpcd_ctx *ctx, const char *file, time_t *time)
 901 {
 902
 903         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_FILEMTIME, 0,
 904             file, strlen(file) + 1) == -1)
 905                 return -1;
 906         return ps_root_readerror(ctx, time, sizeof(*time));
 907 }
 908
 909 #ifdef PRIVSEP_GETIFADDRS
 910 int
 911 ps_root_getifaddrs(struct dhcpcd_ctx *ctx, struct ifaddrs **ifahead)
 912 {
 913         struct ifaddrs *ifa;
 914         void *buf = NULL;
 915         char *bp, *sap;
 916         socklen_t salen;
 917         size_t len;
 918         ssize_t err;
 919
 920         if (ps_sendcmd(ctx, ctx->ps_root_fd,
 921             PS_GETIFADDRS, 0, NULL, 0) == -1)
 922                 return -1;
 923         err = ps_root_mreaderror(ctx, &buf, &len);
 924
 925         if (err == -1)
 926                 return -1;
 927
 928         /* Should be impossible - lo0 will always exist. */
 929         if (len == 0) {
 930                 *ifahead = NULL;
 931                 return 0;
 932         }
 933
 934         bp = buf;
 935         *ifahead = (struct ifaddrs *)(void *)bp;
 936         for (ifa = *ifahead; ifa != NULL; ifa = ifa->ifa_next) {
 937                 if (len < ALIGN(sizeof(*ifa)) +
 938                     ALIGN(IFNAMSIZ) + ALIGN(sizeof(salen) * IFA_NADDRS))
 939                         goto err;
 940                 bp += ALIGN(sizeof(*ifa));
 941                 ifa->ifa_name = bp;
 942                 bp += ALIGN(IFNAMSIZ);
 943                 sap = bp;
 944                 bp += ALIGN(sizeof(salen) * IFA_NADDRS);
 945                 len -= ALIGN(sizeof(*ifa)) +
 946                     ALIGN(IFNAMSIZ) + ALIGN(sizeof(salen) * IFA_NADDRS);
 947
 948 #define COPYOUTSA(addr)                                         \
 949         do {                                                    \
 950                 memcpy(&salen, sap, sizeof(salen));             \
 951                 if (len < salen)                                \
 952                         goto err;                               \
 953                 if (salen != 0) {                               \
 954                         (addr) = (struct sockaddr *)bp;         \
 955                         bp += ALIGN(salen);                     \
 956                         len -= ALIGN(salen);                    \
 957                 }                                               \
 958                 sap += sizeof(salen);                           \
 959         } while (0 /* CONSTCOND */)
 960
 961                 COPYOUTSA(ifa->ifa_addr);
 962                 COPYOUTSA(ifa->ifa_netmask);
 963                 COPYOUTSA(ifa->ifa_broadaddr);
 964
 965                 memcpy(&salen, sap, sizeof(salen));
 966                 if (len < salen)
 967                         goto err;
 968                 if (salen != 0) {
 969                         ifa->ifa_data = bp;
 970                         bp += ALIGN(salen);
 971                         len -= ALIGN(salen);
 972                 } else
 973                         ifa->ifa_data = NULL;
 974
 975                 if (len != 0)
 976                         ifa->ifa_next = (struct ifaddrs *)(void *)bp;
 977                 else
 978                         ifa->ifa_next = NULL;
 979         }
 980         return 0;
 981
 982 err:
 983         free(buf);
 984         *ifahead = NULL;
 985         errno = EINVAL;
 986         return -1;
 987 }
 988 #endif
 989
 990 #if defined(__linux__) || defined(HAVE_PLEDGE)
 991 ssize_t
 992 ps_root_ip6forwarding(struct dhcpcd_ctx *ctx, const char *ifname)
 993 {
 994
 995         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_IP6FORWARDING, 0,
 996             ifname, ifname != NULL ? strlen(ifname) + 1 : 0) == -1)
 997                 return -1;
 998         return ps_root_readerror(ctx, NULL, 0);
 999 }
1000 #endif
1001
1002 #ifdef AUTH
1003 int
1004 ps_root_getauthrdm(struct dhcpcd_ctx *ctx, uint64_t *rdm)
1005 {
1006
1007         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_AUTH_MONORDM, 0,
1008             rdm, sizeof(*rdm))== -1)
1009                 return -1;
1010         return (int)ps_root_readerror(ctx, rdm, sizeof(*rdm));
1011 }
1012 #endif
1013
1014 #ifdef PLUGIN_DEV
1015 int
1016 ps_root_dev_initialised(struct dhcpcd_ctx *ctx, const char *ifname)
1017 {
1018
1019         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_DEV_INITTED, 0,
1020             ifname, strlen(ifname) + 1)== -1)
1021                 return -1;
1022         return (int)ps_root_readerror(ctx, NULL, 0);
1023 }
1024
1025 int
1026 ps_root_dev_listening(struct dhcpcd_ctx * ctx)
1027 {
1028
1029         if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_DEV_LISTENING, 0, NULL, 0)== -1)
1030                 return -1;
1031         return (int)ps_root_readerror(ctx, NULL, 0);
1032 }
1033 #endif