RouteController.cpp revision cf891383224e420d99996f7e63728a7cc902415e
1/* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "RouteController.h" 18 19#include "Fwmark.h" 20#include "UidRanges.h" 21 22#define LOG_TAG "Netd" 23#include "log/log.h" 24#include "logwrap/logwrap.h" 25 26#include <arpa/inet.h> 27#include <linux/fib_rules.h> 28#include <map> 29#include <net/if.h> 30 31namespace { 32 33// BEGIN CONSTANTS -------------------------------------------------------------------------------- 34 35const uint32_t RULE_PRIORITY_PRIVILEGED_LEGACY = 11000; 36const uint32_t RULE_PRIORITY_SECURE_VPN = 12000; 37const uint32_t RULE_PRIORITY_PER_NETWORK_EXPLICIT = 13000; 38const uint32_t RULE_PRIORITY_PER_NETWORK_INTERFACE = 14000; 39const uint32_t RULE_PRIORITY_LEGACY = 16000; 40const uint32_t RULE_PRIORITY_PER_NETWORK_NORMAL = 17000; 41const uint32_t RULE_PRIORITY_DEFAULT_NETWORK = 19000; 42const uint32_t RULE_PRIORITY_MAIN = 20000; 43// TODO: Uncomment once we are sure everything works. 44#if 0 45const uint32_t RULE_PRIORITY_UNREACHABLE = 21000; 46#endif 47 48// TODO: These should be turned into per-UID tables once the kernel supports UID-based routing. 49const int ROUTE_TABLE_PRIVILEGED_LEGACY = RouteController::ROUTE_TABLE_OFFSET_FROM_INDEX - 901; 50const int ROUTE_TABLE_LEGACY = RouteController::ROUTE_TABLE_OFFSET_FROM_INDEX - 902; 51 52// TODO: These values aren't defined by the Linux kernel, because our UID routing changes are not 53// upstream (yet?), so we can't just pick them up from kernel headers. When (if?) the changes make 54// it upstream, we'll remove this and rely on the kernel header values. For now, add a static assert 55// that will warn us if upstream has given these values some other meaning. 56const uint16_t FRA_UID_START = 18; 57const uint16_t FRA_UID_END = 19; 58static_assert(FRA_UID_START > FRA_MAX, 59 "Android-specific FRA_UID_{START,END} values also assigned in Linux uapi. " 60 "Check that these values match what the kernel does and then update this assertion."); 61 62const uint16_t NETLINK_REQUEST_FLAGS = NLM_F_REQUEST | NLM_F_ACK; 63const uint16_t NETLINK_CREATE_REQUEST_FLAGS = NETLINK_REQUEST_FLAGS | NLM_F_CREATE | NLM_F_EXCL; 64 65const sockaddr_nl NETLINK_ADDRESS = {AF_NETLINK, 0, 0, 0}; 66 67const uint8_t AF_FAMILIES[] = {AF_INET, AF_INET6}; 68 69const char* const IP_VERSIONS[] = {"-4", "-6"}; 70 71// Avoids "non-constant-expression cannot be narrowed from type 'unsigned int' to 'unsigned short'" 72// warnings when using RTA_LENGTH(x) inside static initializers (even when x is already uint16_t). 73constexpr uint16_t U16_RTA_LENGTH(uint16_t x) { 74 return RTA_LENGTH(x); 75} 76 77// These are practically const, but can't be declared so, because they are used to initialize 78// non-const pointers ("void* iov_base") in iovec arrays. 79rtattr FRATTR_PRIORITY = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_PRIORITY }; 80rtattr FRATTR_TABLE = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_TABLE }; 81rtattr FRATTR_FWMARK = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_FWMARK }; 82rtattr FRATTR_FWMASK = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_FWMASK }; 83rtattr FRATTR_UID_START = { U16_RTA_LENGTH(sizeof(uid_t)), FRA_UID_START }; 84rtattr FRATTR_UID_END = { U16_RTA_LENGTH(sizeof(uid_t)), FRA_UID_END }; 85 86rtattr RTATTR_TABLE = { U16_RTA_LENGTH(sizeof(uint32_t)), RTA_TABLE }; 87rtattr RTATTR_OIF = { U16_RTA_LENGTH(sizeof(uint32_t)), RTA_OIF }; 88 89uint8_t PADDING_BUFFER[RTA_ALIGNTO] = {0, 0, 0, 0}; 90 91// END CONSTANTS ---------------------------------------------------------------------------------- 92 93std::map<std::string, uint32_t> interfaceToIndex; 94 95uint32_t getRouteTableForInterface(const char* interface) { 96 uint32_t index = if_nametoindex(interface); 97 if (index) { 98 interfaceToIndex[interface] = index; 99 } else { 100 // If the interface goes away if_nametoindex() will return 0 but we still need to know 101 // the index so we can remove the rules and routes. 102 std::map<std::string, uint32_t>::iterator it = interfaceToIndex.find(interface); 103 if (it != interfaceToIndex.end()) { 104 index = it->second; 105 } 106 } 107 return index ? index + RouteController::ROUTE_TABLE_OFFSET_FROM_INDEX : 0; 108} 109 110// Sends a netlink request and expects an ack. 111// |iov| is an array of struct iovec that contains the netlink message payload. 112// The netlink header is generated by this function based on |action| and |flags|. 113// Returns -errno if there was an error or if the kernel reported an error. 114WARN_UNUSED_RESULT int sendNetlinkRequest(uint16_t action, uint16_t flags, iovec* iov, int iovlen) { 115 nlmsghdr nlmsg = { 116 .nlmsg_type = action, 117 .nlmsg_flags = flags, 118 }; 119 iov[0].iov_base = &nlmsg; 120 iov[0].iov_len = sizeof(nlmsg); 121 for (int i = 0; i < iovlen; ++i) { 122 nlmsg.nlmsg_len += iov[i].iov_len; 123 } 124 125 int ret; 126 struct { 127 nlmsghdr msg; 128 nlmsgerr err; 129 } response; 130 131 int sock = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE); 132 if (sock != -1 && 133 connect(sock, reinterpret_cast<const sockaddr*>(&NETLINK_ADDRESS), 134 sizeof(NETLINK_ADDRESS)) != -1 && 135 writev(sock, iov, iovlen) != -1 && 136 (ret = recv(sock, &response, sizeof(response), 0)) != -1) { 137 if (ret == sizeof(response)) { 138 ret = response.err.error; // Netlink errors are negative errno. 139 if (ret) { 140 ALOGE("netlink response contains error (%s)", strerror(-ret)); 141 } 142 } else { 143 ALOGE("bad netlink response message size (%d != %zu)", ret, sizeof(response)); 144 ret = -EBADMSG; 145 } 146 } else { 147 ALOGE("netlink socket/connect/writev/recv failed (%s)", strerror(errno)); 148 ret = -errno; 149 } 150 151 if (sock != -1) { 152 close(sock); 153 } 154 155 return ret; 156} 157 158// Adds or removes a routing rule for IPv4 and IPv6. 159// 160// + If |table| is non-zero, the rule points at the specified routing table. Otherwise, the rule 161// returns ENETUNREACH. 162// + If |mask| is non-zero, the rule matches the specified fwmark and mask. Otherwise, |fwmark| is 163// ignored. 164// + If |interface| is non-NULL, the rule matches the specified outgoing interface. 165// 166// Returns 0 on success or negative errno on failure. 167WARN_UNUSED_RESULT int modifyIpRule(uint16_t action, uint32_t priority, uint32_t table, 168 uint32_t fwmark, uint32_t mask, const char* interface, 169 uid_t uidStart, uid_t uidEnd) { 170 // Ensure that if you set a bit in the fwmark, it's not being ignored by the mask. 171 if (fwmark & ~mask) { 172 ALOGE("mask 0x%x does not select all the bits set in fwmark 0x%x", mask, fwmark); 173 return -ERANGE; 174 } 175 176 // The interface name must include exactly one terminating NULL and be properly padded, or older 177 // kernels will refuse to delete rules. 178 uint16_t paddingLength = 0; 179 size_t interfaceLength = 0; 180 char oifname[IFNAMSIZ]; 181 if (interface) { 182 interfaceLength = strlcpy(oifname, interface, IFNAMSIZ) + 1; 183 if (interfaceLength > IFNAMSIZ) { 184 ALOGE("interface name too long (%zu > %u)", interfaceLength, IFNAMSIZ); 185 return -ENAMETOOLONG; 186 } 187 paddingLength = RTA_SPACE(interfaceLength) - RTA_LENGTH(interfaceLength); 188 } 189 190 // Either both start and end UID must be specified, or neither. 191 if ((uidStart == INVALID_UID) != (uidEnd == INVALID_UID)) { 192 ALOGE("incompatible start and end UIDs (%u vs %u)", uidStart, uidEnd); 193 return -EUSERS; 194 } 195 bool isUidRule = (uidStart != INVALID_UID); 196 197 // Assemble a rule request and put it in an array of iovec structures. 198 fib_rule_hdr rule = { 199 .action = static_cast<uint8_t>(table ? FR_ACT_TO_TBL : FR_ACT_UNREACHABLE), 200 }; 201 202 rtattr fraOifname = { U16_RTA_LENGTH(interfaceLength), FRA_OIFNAME }; 203 204 iovec iov[] = { 205 { NULL, 0 }, 206 { &rule, sizeof(rule) }, 207 { &FRATTR_PRIORITY, sizeof(FRATTR_PRIORITY) }, 208 { &priority, sizeof(priority) }, 209 { &FRATTR_TABLE, table ? sizeof(FRATTR_TABLE) : 0 }, 210 { &table, table ? sizeof(table) : 0 }, 211 { &FRATTR_FWMARK, mask ? sizeof(FRATTR_FWMARK) : 0 }, 212 { &fwmark, mask ? sizeof(fwmark) : 0 }, 213 { &FRATTR_FWMASK, mask ? sizeof(FRATTR_FWMASK) : 0 }, 214 { &mask, mask ? sizeof(mask) : 0 }, 215 { &FRATTR_UID_START, isUidRule ? sizeof(FRATTR_UID_START) : 0 }, 216 { &uidStart, isUidRule ? sizeof(uidStart) : 0 }, 217 { &FRATTR_UID_END, isUidRule ? sizeof(FRATTR_UID_END) : 0 }, 218 { &uidEnd, isUidRule ? sizeof(uidEnd) : 0 }, 219 { &fraOifname, interface ? sizeof(fraOifname) : 0 }, 220 { oifname, interfaceLength }, 221 { PADDING_BUFFER, paddingLength }, 222 }; 223 224 uint16_t flags = (action == RTM_NEWRULE) ? NETLINK_CREATE_REQUEST_FLAGS : NETLINK_REQUEST_FLAGS; 225 for (size_t i = 0; i < ARRAY_SIZE(AF_FAMILIES); ++i) { 226 rule.family = AF_FAMILIES[i]; 227 if (int ret = sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov))) { 228 return ret; 229 } 230 } 231 232 return 0; 233} 234 235// Adds or deletes an IPv4 or IPv6 route. 236// Returns 0 on success or negative errno on failure. 237WARN_UNUSED_RESULT int modifyIpRoute(uint16_t action, uint32_t table, const char* interface, 238 const char* destination, const char* nexthop) { 239 // At least the destination must be non-null. 240 if (!destination) { 241 ALOGE("null destination"); 242 return -EFAULT; 243 } 244 245 // Parse the prefix. 246 uint8_t rawAddress[sizeof(in6_addr)]; 247 uint8_t family; 248 uint8_t prefixLength; 249 int rawLength = parsePrefix(destination, &family, rawAddress, sizeof(rawAddress), 250 &prefixLength); 251 if (rawLength < 0) { 252 ALOGE("parsePrefix failed for destination %s (%s)", destination, strerror(-rawLength)); 253 return rawLength; 254 } 255 256 if (static_cast<size_t>(rawLength) > sizeof(rawAddress)) { 257 ALOGE("impossible! address too long (%d vs %zu)", rawLength, sizeof(rawAddress)); 258 return -ENOBUFS; // Cannot happen; parsePrefix only supports IPv4 and IPv6. 259 } 260 261 // If an interface was specified, find the ifindex. 262 uint32_t ifindex; 263 if (interface) { 264 ifindex = if_nametoindex(interface); 265 if (!ifindex) { 266 ALOGE("cannot find interface %s", interface); 267 return -ENODEV; 268 } 269 } 270 271 // If a nexthop was specified, parse it as the same family as the prefix. 272 uint8_t rawNexthop[sizeof(in6_addr)]; 273 if (nexthop && inet_pton(family, nexthop, rawNexthop) <= 0) { 274 ALOGE("inet_pton failed for nexthop %s", nexthop); 275 return -EINVAL; 276 } 277 278 // Assemble a rtmsg and put it in an array of iovec structures. 279 rtmsg route = { 280 .rtm_protocol = RTPROT_STATIC, 281 .rtm_type = RTN_UNICAST, 282 .rtm_family = family, 283 .rtm_dst_len = prefixLength, 284 }; 285 286 rtattr rtaDst = { U16_RTA_LENGTH(rawLength), RTA_DST }; 287 rtattr rtaGateway = { U16_RTA_LENGTH(rawLength), RTA_GATEWAY }; 288 289 iovec iov[] = { 290 { NULL, 0 }, 291 { &route, sizeof(route) }, 292 { &RTATTR_TABLE, sizeof(RTATTR_TABLE) }, 293 { &table, sizeof(table) }, 294 { &rtaDst, sizeof(rtaDst) }, 295 { rawAddress, static_cast<size_t>(rawLength) }, 296 { &RTATTR_OIF, interface ? sizeof(RTATTR_OIF) : 0 }, 297 { &ifindex, interface ? sizeof(ifindex) : 0 }, 298 { &rtaGateway, nexthop ? sizeof(rtaGateway) : 0 }, 299 { rawNexthop, nexthop ? static_cast<size_t>(rawLength) : 0 }, 300 }; 301 302 uint16_t flags = (action == RTM_NEWROUTE) ? NETLINK_CREATE_REQUEST_FLAGS : 303 NETLINK_REQUEST_FLAGS; 304 return sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov)); 305} 306 307WARN_UNUSED_RESULT int modifyIncomingPacketMark(unsigned netId, const char* interface, bool add) { 308 // An iptables rule to mark incoming packets on a network with the netId of the network. 309 // 310 // This is so that the kernel can: 311 // + Use the right fwmark for (and thus correctly route) replies (e.g.: TCP RST, ICMP errors, 312 // ping replies). 313 // + Mark sockets that accept connections from this interface so that the connection stays on 314 // the same interface. 315 char markString[UINT32_HEX_STRLEN]; 316 snprintf(markString, sizeof(markString), "0x%x", netId); 317 if (execIptables(V4V6, "-t", "mangle", add ? "-A" : "-D", "INPUT", "-i", interface, "-j", 318 "MARK", "--set-mark", markString, NULL)) { 319 ALOGE("failed to change iptables rule that sets incoming packet mark"); 320 return -EREMOTEIO; 321 } 322 return 0; 323} 324 325WARN_UNUSED_RESULT int modifyPerNetworkRules(unsigned netId, const char* interface, uint32_t table, 326 Permission permission, uid_t uidStart, uid_t uidEnd, 327 bool add, bool modifyIptables) { 328 if (!table) { 329 table = getRouteTableForInterface(interface); 330 if (!table) { 331 ALOGE("cannot find interface %s", interface); 332 return -ESRCH; 333 } 334 } 335 336 uint16_t action = add ? RTM_NEWRULE : RTM_DELRULE; 337 338 Fwmark fwmark; 339 Fwmark mask; 340 341 // A rule to route traffic based on a chosen outgoing interface. 342 // 343 // Supports apps that use SO_BINDTODEVICE or IP_PKTINFO options and the kernel that already 344 // knows the outgoing interface (typically for link-local communications). 345 fwmark.permission = permission; 346 mask.permission = permission; 347 if (int ret = modifyIpRule(action, RULE_PRIORITY_PER_NETWORK_INTERFACE, table, fwmark.intValue, 348 mask.intValue, interface, uidStart, uidEnd)) { 349 return ret; 350 } 351 352 // A rule to route traffic based on the chosen network. 353 // 354 // This is for sockets that have not explicitly requested a particular network, but have been 355 // bound to one when they called connect(). This ensures that sockets connected on a particular 356 // network stay on that network even if the default network changes. 357 fwmark.netId = netId; 358 mask.netId = FWMARK_NET_ID_MASK; 359 if (int ret = modifyIpRule(action, RULE_PRIORITY_PER_NETWORK_NORMAL, table, fwmark.intValue, 360 mask.intValue, NULL, uidStart, uidEnd)) { 361 return ret; 362 } 363 364 // A rule to route traffic based on an explicitly chosen network. 365 // 366 // Supports apps that use the multinetwork APIs to restrict their traffic to a network. 367 // 368 // Even though we check permissions at the time we set a netId into the fwmark of a socket, we 369 // still need to check it again in the rules here, because a network's permissions may have been 370 // updated via modifyNetworkPermission(). 371 fwmark.explicitlySelected = true; 372 mask.explicitlySelected = true; 373 if (int ret = modifyIpRule(action, RULE_PRIORITY_PER_NETWORK_EXPLICIT, table, fwmark.intValue, 374 mask.intValue, NULL, uidStart, uidEnd)) { 375 return ret; 376 } 377 378 if (modifyIptables) { 379 if (int ret = modifyIncomingPacketMark(netId, interface, add)) { 380 return ret; 381 } 382 } 383 384 return 0; 385} 386 387// Adds or removes rules for VPNs that affect UIDs in |uidRanges|. If |modifyInterfaceBasedRules| 388// is true, also modifies the rules that are based only on the |interface| and not on |uidRanges|. 389// When adding or removing an interface to the VPN, set it to true. When adding or removing UIDs 390// without changing the VPN's interfaces, set it to false. 391WARN_UNUSED_RESULT int modifyVpnRules(unsigned netId, const char* interface, 392 const UidRanges& uidRanges, bool add, 393 bool modifyInterfaceBasedRules) { 394 uint32_t table = getRouteTableForInterface(interface); 395 if (!table) { 396 ALOGE("cannot find interface %s", interface); 397 return -ESRCH; 398 } 399 400 uint16_t action = add ? RTM_NEWRULE : RTM_DELRULE; 401 402 Fwmark fwmark; 403 Fwmark mask; 404 405 fwmark.protectedFromVpn = false; 406 mask.protectedFromVpn = true; 407 408 for (const std::pair<uid_t, uid_t>& range : uidRanges.getRanges()) { 409 if (int ret = modifyPerNetworkRules(netId, interface, table, PERMISSION_NONE, range.first, 410 range.second, add, false)) { 411 return ret; 412 } 413 414 // A rule to route all traffic from a given set of UIDs to go over the VPN. 415 // 416 // Notice that this rule doesn't use the netId. I.e., no matter what netId the user's socket 417 // may have, if they are subject to this VPN, their traffic has to go through it. Allows the 418 // traffic to bypass the VPN if the protectedFromVpn bit is set. 419 if (int ret = modifyIpRule(action, RULE_PRIORITY_SECURE_VPN, table, fwmark.intValue, 420 mask.intValue, NULL, range.first, range.second)) { 421 return ret; 422 } 423 } 424 425 if (modifyInterfaceBasedRules) { 426 if (int ret = modifyIncomingPacketMark(netId, interface, add)) { 427 return ret; 428 } 429 430 // A rule to allow privileged apps to send traffic over this VPN even if they are not part 431 // of the target set of UIDs. 432 // 433 // This is needed for DnsProxyListener to correctly resolve a request for a user who is in 434 // the target set, but where the DnsProxyListener itself is not. 435 fwmark.protectedFromVpn = false; 436 mask.protectedFromVpn = false; 437 438 fwmark.netId = netId; 439 mask.netId = FWMARK_NET_ID_MASK; 440 441 fwmark.permission = PERMISSION_CONNECTIVITY_INTERNAL; 442 mask.permission = PERMISSION_CONNECTIVITY_INTERNAL; 443 444 if (int ret = modifyIpRule(action, RULE_PRIORITY_SECURE_VPN, table, fwmark.intValue, 445 mask.intValue, NULL, INVALID_UID, INVALID_UID)) { 446 return ret; 447 } 448 } 449 450 return 0; 451} 452 453WARN_UNUSED_RESULT int modifyDefaultNetworkRules(const char* interface, Permission permission, 454 uint16_t action) { 455 uint32_t table = getRouteTableForInterface(interface); 456 if (!table) { 457 ALOGE("cannot find interface %s", interface); 458 return -ESRCH; 459 } 460 461 Fwmark fwmark; 462 Fwmark mask; 463 464 fwmark.netId = 0; 465 mask.netId = FWMARK_NET_ID_MASK; 466 467 fwmark.permission = permission; 468 mask.permission = permission; 469 470 return modifyIpRule(action, RULE_PRIORITY_DEFAULT_NETWORK, table, fwmark.intValue, 471 mask.intValue, NULL, INVALID_UID, INVALID_UID); 472} 473 474// Adds or removes an IPv4 or IPv6 route to the specified table and, if it's a directly-connected 475// route, to the main table as well. 476// Returns 0 on success or negative errno on failure. 477WARN_UNUSED_RESULT int modifyRoute(const char* interface, const char* destination, 478 const char* nexthop, uint16_t action, 479 RouteController::TableType tableType, uid_t /*uid*/) { 480 uint32_t table = 0; 481 switch (tableType) { 482 case RouteController::INTERFACE: { 483 table = getRouteTableForInterface(interface); 484 break; 485 } 486 case RouteController::LEGACY: { 487 // TODO: Use the UID to assign a unique table per UID instead of this fixed table. 488 table = ROUTE_TABLE_LEGACY; 489 break; 490 } 491 case RouteController::PRIVILEGED_LEGACY: { 492 // TODO: Use the UID to assign a unique table per UID instead of this fixed table. 493 table = ROUTE_TABLE_PRIVILEGED_LEGACY; 494 break; 495 } 496 } 497 if (!table) { 498 ALOGE("cannot find table for interface %s and tableType %d", interface, tableType); 499 return -ESRCH; 500 } 501 502 int ret = modifyIpRoute(action, table, interface, destination, nexthop); 503 // We allow apps to call requestRouteToHost() multiple times with the same route, so ignore 504 // EEXIST failures when adding routes to legacy tables. 505 if (ret != 0 && !(action == RTM_NEWROUTE && ret == -EEXIST && 506 (tableType == RouteController::LEGACY || 507 tableType == RouteController::PRIVILEGED_LEGACY))) { 508 return ret; 509 } 510 511 // If there's no nexthop, this is a directly connected route. Add it to the main table also, to 512 // let the kernel find it when validating nexthops when global routes are added. 513 if (!nexthop) { 514 ret = modifyIpRoute(action, RT_TABLE_MAIN, interface, destination, NULL); 515 // A failure with action == ADD && errno == EEXIST means that the route already exists in 516 // the main table, perhaps because the kernel added it automatically as part of adding the 517 // IP address to the interface. Ignore this, but complain about everything else. 518 if (ret && !(action == RTM_NEWROUTE && ret == -EEXIST)) { 519 return ret; 520 } 521 } 522 523 return 0; 524} 525 526// Returns 0 on success or negative errno on failure. 527WARN_UNUSED_RESULT int flushRoutes(const char* interface) { 528 uint32_t table = getRouteTableForInterface(interface); 529 if (!table) { 530 ALOGE("cannot find interface %s", interface); 531 return -ESRCH; 532 } 533 interfaceToIndex.erase(interface); 534 535 char tableString[UINT32_STRLEN]; 536 snprintf(tableString, sizeof(tableString), "%u", table); 537 538 for (size_t i = 0; i < ARRAY_SIZE(IP_VERSIONS); ++i) { 539 const char* argv[] = { 540 IP_PATH, 541 IP_VERSIONS[i], 542 "route" 543 "flush", 544 "table", 545 tableString, 546 }; 547 if (android_fork_execvp(ARRAY_SIZE(argv), const_cast<char**>(argv), NULL, false, false)) { 548 ALOGE("failed to flush routes"); 549 return -EREMOTEIO; 550 } 551 } 552 553 return 0; 554} 555 556} // namespace 557 558int RouteController::Init() { 559 Fwmark fwmark; 560 Fwmark mask; 561 562 // Add a new rule to look up the 'main' table, with the same selectors as the "default network" 563 // rule, but with a lower priority. Since the default network rule points to a table with a 564 // default route, the rule we're adding will never be used for normal routing lookups. However, 565 // the kernel may fall-through to it to find directly-connected routes when it validates that a 566 // nexthop (in a route being added) is reachable. 567 // 568 // TODO: This isn't true if the default network requires non-zero permissions. In that case, an 569 // app without those permissions may still be able to access directly-connected routes, since 570 // it won't match the default network rule. Fix this by only allowing the root UID (as a proxy 571 // for the kernel) to lookup this main table rule. 572 fwmark.netId = 0; 573 mask.netId = FWMARK_NET_ID_MASK; 574 if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_MAIN, RT_TABLE_MAIN, fwmark.intValue, 575 mask.intValue, NULL, INVALID_UID, INVALID_UID)) { 576 return ret; 577 } 578 579 // Add rules to allow lookup of legacy routes. 580 // 581 // TODO: Remove these once the kernel supports UID-based routing. Instead, add them on demand 582 // when routes are added. 583 fwmark.netId = 0; 584 mask.netId = 0; 585 586 fwmark.explicitlySelected = false; 587 mask.explicitlySelected = true; 588 if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LEGACY, ROUTE_TABLE_LEGACY, 589 fwmark.intValue, mask.intValue, NULL, INVALID_UID, INVALID_UID)) { 590 return ret; 591 } 592 593 fwmark.permission = PERMISSION_CONNECTIVITY_INTERNAL; 594 mask.permission = PERMISSION_CONNECTIVITY_INTERNAL; 595 596 if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_PRIVILEGED_LEGACY, 597 ROUTE_TABLE_PRIVILEGED_LEGACY, fwmark.intValue, mask.intValue, NULL, 598 INVALID_UID, INVALID_UID)) { 599 return ret; 600 } 601 602// TODO: Uncomment once we are sure everything works. 603#if 0 604 // Add a rule to preempt the pre-defined "from all lookup main" rule. This ensures that packets 605 // that are already marked with a specific NetId don't fall-through to the main table. 606 return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_UNREACHABLE, 0, 0, 0, NULL, INVALID_UID, 607 INVALID_UID); 608#else 609 return 0; 610#endif 611} 612 613int RouteController::addInterfaceToNetwork(unsigned netId, const char* interface, 614 Permission permission) { 615 return modifyPerNetworkRules(netId, interface, 0, permission, INVALID_UID, INVALID_UID, true, 616 true); 617} 618 619int RouteController::removeInterfaceFromNetwork(unsigned netId, const char* interface, 620 Permission permission) { 621 if (int ret = modifyPerNetworkRules(netId, interface, 0, permission, INVALID_UID, INVALID_UID, 622 false, true)) { 623 return ret; 624 } 625 return flushRoutes(interface); 626} 627 628int RouteController::addInterfaceToVpn(unsigned netId, const char* interface, 629 const UidRanges& uidRanges) { 630 return modifyVpnRules(netId, interface, uidRanges, true, true); 631} 632 633int RouteController::removeInterfaceFromVpn(unsigned netId, const char* interface, 634 const UidRanges& uidRanges) { 635 if (int ret = modifyVpnRules(netId, interface, uidRanges, false, true)) { 636 return ret; 637 } 638 return flushRoutes(interface); 639} 640 641int RouteController::modifyNetworkPermission(unsigned netId, const char* interface, 642 Permission oldPermission, Permission newPermission) { 643 // Add the new rules before deleting the old ones, to avoid race conditions. 644 if (int ret = modifyPerNetworkRules(netId, interface, 0, newPermission, INVALID_UID, 645 INVALID_UID, true, false)) { 646 return ret; 647 } 648 return modifyPerNetworkRules(netId, interface, 0, oldPermission, INVALID_UID, INVALID_UID, 649 false, false); 650} 651 652int RouteController::addUsersToVpn(unsigned netId, const char* interface, 653 const UidRanges& uidRanges) { 654 return modifyVpnRules(netId, interface, uidRanges, true, false); 655} 656 657int RouteController::removeUsersFromVpn(unsigned netId, const char* interface, 658 const UidRanges& uidRanges) { 659 return modifyVpnRules(netId, interface, uidRanges, false, false); 660} 661 662int RouteController::addToDefaultNetwork(const char* interface, Permission permission) { 663 return modifyDefaultNetworkRules(interface, permission, RTM_NEWRULE); 664} 665 666int RouteController::removeFromDefaultNetwork(const char* interface, Permission permission) { 667 return modifyDefaultNetworkRules(interface, permission, RTM_DELRULE); 668} 669 670int RouteController::addRoute(const char* interface, const char* destination, const char* nexthop, 671 TableType tableType, uid_t uid) { 672 return modifyRoute(interface, destination, nexthop, RTM_NEWROUTE, tableType, uid); 673} 674 675int RouteController::removeRoute(const char* interface, const char* destination, 676 const char* nexthop, TableType tableType, uid_t uid) { 677 return modifyRoute(interface, destination, nexthop, RTM_DELROUTE, tableType, uid); 678} 679