| /* |
| * Copyright (C) 2014 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "RouteController.h" |
| |
| #include "Fwmark.h" |
| #include "UidRanges.h" |
| |
| #define LOG_TAG "Netd" |
| #include "log/log.h" |
| #include "logwrap/logwrap.h" |
| #include "resolv_netid.h" |
| |
| #include <arpa/inet.h> |
| #include <fcntl.h> |
| #include <linux/fib_rules.h> |
| #include <map> |
| #include <net/if.h> |
| #include <sys/stat.h> |
| |
| namespace { |
| |
| // BEGIN CONSTANTS -------------------------------------------------------------------------------- |
| |
| const uint32_t RULE_PRIORITY_VPN_OVERRIDE_SYSTEM = 10000; |
| const uint32_t RULE_PRIORITY_VPN_OUTPUT_TO_LOCAL = 11000; |
| const uint32_t RULE_PRIORITY_SECURE_VPN = 12000; |
| const uint32_t RULE_PRIORITY_EXPLICIT_NETWORK = 13000; |
| const uint32_t RULE_PRIORITY_OUTPUT_INTERFACE = 14000; |
| const uint32_t RULE_PRIORITY_LEGACY_SYSTEM = 15000; |
| const uint32_t RULE_PRIORITY_LEGACY_NETWORK = 16000; |
| const uint32_t RULE_PRIORITY_LOCAL_NETWORK = 17000; |
| const uint32_t RULE_PRIORITY_TETHERING = 18000; |
| const uint32_t RULE_PRIORITY_IMPLICIT_NETWORK = 19000; |
| const uint32_t RULE_PRIORITY_BYPASSABLE_VPN = 20000; |
| const uint32_t RULE_PRIORITY_VPN_FALLTHROUGH = 21000; |
| const uint32_t RULE_PRIORITY_DEFAULT_NETWORK = 22000; |
| const uint32_t RULE_PRIORITY_DIRECTLY_CONNECTED = 23000; |
| const uint32_t RULE_PRIORITY_UNREACHABLE = 32000; |
| |
| const uint32_t ROUTE_TABLE_LOCAL_NETWORK = 97; |
| const uint32_t ROUTE_TABLE_LEGACY_NETWORK = 98; |
| const uint32_t ROUTE_TABLE_LEGACY_SYSTEM = 99; |
| |
| const char* const ROUTE_TABLE_NAME_LOCAL_NETWORK = "local_network"; |
| const char* const ROUTE_TABLE_NAME_LEGACY_NETWORK = "legacy_network"; |
| const char* const ROUTE_TABLE_NAME_LEGACY_SYSTEM = "legacy_system"; |
| |
| const char* const ROUTE_TABLE_NAME_LOCAL = "local"; |
| const char* const ROUTE_TABLE_NAME_MAIN = "main"; |
| |
| // TODO: These values aren't defined by the Linux kernel, because our UID routing changes are not |
| // upstream (yet?), so we can't just pick them up from kernel headers. When (if?) the changes make |
| // it upstream, we'll remove this and rely on the kernel header values. For now, add a static assert |
| // that will warn us if upstream has given these values some other meaning. |
| const uint16_t FRA_UID_START = 18; |
| const uint16_t FRA_UID_END = 19; |
| static_assert(FRA_UID_START > FRA_MAX, |
| "Android-specific FRA_UID_{START,END} values also assigned in Linux uapi. " |
| "Check that these values match what the kernel does and then update this assertion."); |
| |
| const uint16_t NETLINK_REQUEST_FLAGS = NLM_F_REQUEST | NLM_F_ACK; |
| const uint16_t NETLINK_CREATE_REQUEST_FLAGS = NETLINK_REQUEST_FLAGS | NLM_F_CREATE | NLM_F_EXCL; |
| |
| const sockaddr_nl NETLINK_ADDRESS = {AF_NETLINK, 0, 0, 0}; |
| |
| const uint8_t AF_FAMILIES[] = {AF_INET, AF_INET6}; |
| |
| const char* const IP_VERSIONS[] = {"-4", "-6"}; |
| |
| const uid_t UID_ROOT = 0; |
| const char* const IIF_NONE = NULL; |
| const char* const OIF_NONE = NULL; |
| const bool ACTION_ADD = true; |
| const bool ACTION_DEL = false; |
| const bool MODIFY_NON_UID_BASED_RULES = true; |
| |
| const char* const RT_TABLES_PATH = "/data/misc/net/rt_tables"; |
| const int RT_TABLES_FLAGS = O_CREAT | O_TRUNC | O_WRONLY | O_NOFOLLOW | O_CLOEXEC; |
| const mode_t RT_TABLES_MODE = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH; // mode 0644, rw-r--r-- |
| |
| // Avoids "non-constant-expression cannot be narrowed from type 'unsigned int' to 'unsigned short'" |
| // warnings when using RTA_LENGTH(x) inside static initializers (even when x is already uint16_t). |
| constexpr uint16_t U16_RTA_LENGTH(uint16_t x) { |
| return RTA_LENGTH(x); |
| } |
| |
| // These are practically const, but can't be declared so, because they are used to initialize |
| // non-const pointers ("void* iov_base") in iovec arrays. |
| rtattr FRATTR_PRIORITY = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_PRIORITY }; |
| rtattr FRATTR_TABLE = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_TABLE }; |
| rtattr FRATTR_FWMARK = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_FWMARK }; |
| rtattr FRATTR_FWMASK = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_FWMASK }; |
| rtattr FRATTR_UID_START = { U16_RTA_LENGTH(sizeof(uid_t)), FRA_UID_START }; |
| rtattr FRATTR_UID_END = { U16_RTA_LENGTH(sizeof(uid_t)), FRA_UID_END }; |
| |
| rtattr RTATTR_TABLE = { U16_RTA_LENGTH(sizeof(uint32_t)), RTA_TABLE }; |
| rtattr RTATTR_OIF = { U16_RTA_LENGTH(sizeof(uint32_t)), RTA_OIF }; |
| |
| uint8_t PADDING_BUFFER[RTA_ALIGNTO] = {0, 0, 0, 0}; |
| |
| // END CONSTANTS ---------------------------------------------------------------------------------- |
| |
| // No locks needed because RouteController is accessed only from one thread (in CommandListener). |
| std::map<std::string, uint32_t> interfaceToTable; |
| |
| uint32_t getRouteTableForInterface(const char* interface) { |
| uint32_t index = if_nametoindex(interface); |
| if (index) { |
| index += RouteController::ROUTE_TABLE_OFFSET_FROM_INDEX; |
| interfaceToTable[interface] = index; |
| return index; |
| } |
| // If the interface goes away if_nametoindex() will return 0 but we still need to know |
| // the index so we can remove the rules and routes. |
| auto iter = interfaceToTable.find(interface); |
| if (iter == interfaceToTable.end()) { |
| ALOGE("cannot find interface %s", interface); |
| return RT_TABLE_UNSPEC; |
| } |
| return iter->second; |
| } |
| |
| void addTableName(uint32_t table, const std::string& name, std::string* contents) { |
| char tableString[UINT32_STRLEN]; |
| snprintf(tableString, sizeof(tableString), "%u", table); |
| *contents += tableString; |
| *contents += " "; |
| *contents += name; |
| *contents += "\n"; |
| } |
| |
| // Doesn't return success/failure as the file is optional; it's okay if we fail to update it. |
| void updateTableNamesFile() { |
| std::string contents; |
| |
| addTableName(RT_TABLE_LOCAL, ROUTE_TABLE_NAME_LOCAL, &contents); |
| addTableName(RT_TABLE_MAIN, ROUTE_TABLE_NAME_MAIN, &contents); |
| |
| addTableName(ROUTE_TABLE_LOCAL_NETWORK, ROUTE_TABLE_NAME_LOCAL_NETWORK, &contents); |
| addTableName(ROUTE_TABLE_LEGACY_NETWORK, ROUTE_TABLE_NAME_LEGACY_NETWORK, &contents); |
| addTableName(ROUTE_TABLE_LEGACY_SYSTEM, ROUTE_TABLE_NAME_LEGACY_SYSTEM, &contents); |
| |
| for (const auto& entry : interfaceToTable) { |
| addTableName(entry.second, entry.first, &contents); |
| } |
| |
| int fd = open(RT_TABLES_PATH, RT_TABLES_FLAGS, RT_TABLES_MODE); |
| if (fd == -1) { |
| ALOGE("failed to create %s (%s)", RT_TABLES_PATH, strerror(errno)); |
| return; |
| } |
| // File creation is affected by umask, so make sure the right mode bits are set. |
| if (fchmod(fd, RT_TABLES_MODE) == -1) { |
| ALOGE("failed to set mode 0%o on %s (%s)", RT_TABLES_MODE, RT_TABLES_PATH, strerror(errno)); |
| } |
| ssize_t bytesWritten = write(fd, contents.data(), contents.size()); |
| if (bytesWritten != static_cast<ssize_t>(contents.size())) { |
| ALOGE("failed to write to %s (%zd vs %zu bytes) (%s)", RT_TABLES_PATH, bytesWritten, |
| contents.size(), strerror(errno)); |
| } |
| close(fd); |
| } |
| |
| // Sends a netlink request and expects an ack. |
| // |iov| is an array of struct iovec that contains the netlink message payload. |
| // The netlink header is generated by this function based on |action| and |flags|. |
| // Returns -errno if there was an error or if the kernel reported an error. |
| WARN_UNUSED_RESULT int sendNetlinkRequest(uint16_t action, uint16_t flags, iovec* iov, int iovlen) { |
| nlmsghdr nlmsg = { |
| .nlmsg_type = action, |
| .nlmsg_flags = flags, |
| }; |
| iov[0].iov_base = &nlmsg; |
| iov[0].iov_len = sizeof(nlmsg); |
| for (int i = 0; i < iovlen; ++i) { |
| nlmsg.nlmsg_len += iov[i].iov_len; |
| } |
| |
| int ret; |
| struct { |
| nlmsghdr msg; |
| nlmsgerr err; |
| } response; |
| |
| int sock = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE); |
| if (sock != -1 && |
| connect(sock, reinterpret_cast<const sockaddr*>(&NETLINK_ADDRESS), |
| sizeof(NETLINK_ADDRESS)) != -1 && |
| writev(sock, iov, iovlen) != -1 && |
| (ret = recv(sock, &response, sizeof(response), 0)) != -1) { |
| if (ret == sizeof(response)) { |
| ret = response.err.error; // Netlink errors are negative errno. |
| if (ret) { |
| ALOGE("netlink response contains error (%s)", strerror(-ret)); |
| } |
| } else { |
| ALOGE("bad netlink response message size (%d != %zu)", ret, sizeof(response)); |
| ret = -EBADMSG; |
| } |
| } else { |
| ALOGE("netlink socket/connect/writev/recv failed (%s)", strerror(errno)); |
| ret = -errno; |
| } |
| |
| if (sock != -1) { |
| close(sock); |
| } |
| |
| return ret; |
| } |
| |
| // Returns 0 on success or negative errno on failure. |
| int padInterfaceName(const char* input, char* name, size_t* length, uint16_t* padding) { |
| if (!input) { |
| *length = 0; |
| *padding = 0; |
| return 0; |
| } |
| *length = strlcpy(name, input, IFNAMSIZ) + 1; |
| if (*length > IFNAMSIZ) { |
| ALOGE("interface name too long (%zu > %u)", *length, IFNAMSIZ); |
| return -ENAMETOOLONG; |
| } |
| *padding = RTA_SPACE(*length) - RTA_LENGTH(*length); |
| return 0; |
| } |
| |
| // Adds or removes a routing rule for IPv4 and IPv6. |
| // |
| // + If |table| is non-zero, the rule points at the specified routing table. Otherwise, the rule |
| // returns ENETUNREACH. |
| // + If |mask| is non-zero, the rule matches the specified fwmark and mask. Otherwise, |fwmark| is |
| // ignored. |
| // + If |iif| is non-NULL, the rule matches the specified incoming interface. |
| // + If |oif| is non-NULL, the rule matches the specified outgoing interface. |
| // + If |uidStart| and |uidEnd| are not INVALID_UID, the rule matches packets from UIDs in that |
| // range (inclusive). Otherwise, the rule matches packets from all UIDs. |
| // |
| // Returns 0 on success or negative errno on failure. |
| WARN_UNUSED_RESULT int modifyIpRule(uint16_t action, uint32_t priority, uint32_t table, |
| uint32_t fwmark, uint32_t mask, const char* iif, |
| const char* oif, uid_t uidStart, uid_t uidEnd) { |
| // Ensure that if you set a bit in the fwmark, it's not being ignored by the mask. |
| if (fwmark & ~mask) { |
| ALOGE("mask 0x%x does not select all the bits set in fwmark 0x%x", mask, fwmark); |
| return -ERANGE; |
| } |
| |
| // Interface names must include exactly one terminating NULL and be properly padded, or older |
| // kernels will refuse to delete rules. |
| char iifName[IFNAMSIZ], oifName[IFNAMSIZ]; |
| size_t iifLength, oifLength; |
| uint16_t iifPadding, oifPadding; |
| if (int ret = padInterfaceName(iif, iifName, &iifLength, &iifPadding)) { |
| return ret; |
| } |
| if (int ret = padInterfaceName(oif, oifName, &oifLength, &oifPadding)) { |
| return ret; |
| } |
| |
| // Either both start and end UID must be specified, or neither. |
| if ((uidStart == INVALID_UID) != (uidEnd == INVALID_UID)) { |
| ALOGE("incompatible start and end UIDs (%u vs %u)", uidStart, uidEnd); |
| return -EUSERS; |
| } |
| bool isUidRule = (uidStart != INVALID_UID); |
| |
| // Assemble a rule request and put it in an array of iovec structures. |
| fib_rule_hdr rule = { |
| .action = static_cast<uint8_t>(table != RT_TABLE_UNSPEC ? FR_ACT_TO_TBL : |
| FR_ACT_UNREACHABLE), |
| }; |
| |
| rtattr fraIifName = { U16_RTA_LENGTH(iifLength), FRA_IIFNAME }; |
| rtattr fraOifName = { U16_RTA_LENGTH(oifLength), FRA_OIFNAME }; |
| |
| iovec iov[] = { |
| { NULL, 0 }, |
| { &rule, sizeof(rule) }, |
| { &FRATTR_PRIORITY, sizeof(FRATTR_PRIORITY) }, |
| { &priority, sizeof(priority) }, |
| { &FRATTR_TABLE, table != RT_TABLE_UNSPEC ? sizeof(FRATTR_TABLE) : 0 }, |
| { &table, table != RT_TABLE_UNSPEC ? sizeof(table) : 0 }, |
| { &FRATTR_FWMARK, mask ? sizeof(FRATTR_FWMARK) : 0 }, |
| { &fwmark, mask ? sizeof(fwmark) : 0 }, |
| { &FRATTR_FWMASK, mask ? sizeof(FRATTR_FWMASK) : 0 }, |
| { &mask, mask ? sizeof(mask) : 0 }, |
| { &FRATTR_UID_START, isUidRule ? sizeof(FRATTR_UID_START) : 0 }, |
| { &uidStart, isUidRule ? sizeof(uidStart) : 0 }, |
| { &FRATTR_UID_END, isUidRule ? sizeof(FRATTR_UID_END) : 0 }, |
| { &uidEnd, isUidRule ? sizeof(uidEnd) : 0 }, |
| { &fraIifName, iif != IIF_NONE ? sizeof(fraIifName) : 0 }, |
| { iifName, iifLength }, |
| { PADDING_BUFFER, iifPadding }, |
| { &fraOifName, oif != OIF_NONE ? sizeof(fraOifName) : 0 }, |
| { oifName, oifLength }, |
| { PADDING_BUFFER, oifPadding }, |
| }; |
| |
| uint16_t flags = (action == RTM_NEWRULE) ? NETLINK_CREATE_REQUEST_FLAGS : NETLINK_REQUEST_FLAGS; |
| for (size_t i = 0; i < ARRAY_SIZE(AF_FAMILIES); ++i) { |
| rule.family = AF_FAMILIES[i]; |
| if (int ret = sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov))) { |
| return ret; |
| } |
| } |
| |
| return 0; |
| } |
| |
| WARN_UNUSED_RESULT int modifyIpRule(uint16_t action, uint32_t priority, uint32_t table, |
| uint32_t fwmark, uint32_t mask) { |
| return modifyIpRule(action, priority, table, fwmark, mask, IIF_NONE, OIF_NONE, INVALID_UID, |
| INVALID_UID); |
| } |
| |
| // Adds or deletes an IPv4 or IPv6 route. |
| // Returns 0 on success or negative errno on failure. |
| WARN_UNUSED_RESULT int modifyIpRoute(uint16_t action, uint32_t table, const char* interface, |
| const char* destination, const char* nexthop) { |
| // At least the destination must be non-null. |
| if (!destination) { |
| ALOGE("null destination"); |
| return -EFAULT; |
| } |
| |
| // Parse the prefix. |
| uint8_t rawAddress[sizeof(in6_addr)]; |
| uint8_t family; |
| uint8_t prefixLength; |
| int rawLength = parsePrefix(destination, &family, rawAddress, sizeof(rawAddress), |
| &prefixLength); |
| if (rawLength < 0) { |
| ALOGE("parsePrefix failed for destination %s (%s)", destination, strerror(-rawLength)); |
| return rawLength; |
| } |
| |
| if (static_cast<size_t>(rawLength) > sizeof(rawAddress)) { |
| ALOGE("impossible! address too long (%d vs %zu)", rawLength, sizeof(rawAddress)); |
| return -ENOBUFS; // Cannot happen; parsePrefix only supports IPv4 and IPv6. |
| } |
| |
| uint8_t type = RTN_UNICAST; |
| uint32_t ifindex; |
| uint8_t rawNexthop[sizeof(in6_addr)]; |
| |
| if (nexthop && !strcmp(nexthop, "unreachable")) { |
| type = RTN_UNREACHABLE; |
| // 'interface' is likely non-NULL, as the caller (modifyRoute()) likely used it to lookup |
| // the table number. But it's an error to specify an interface ("dev ...") or a nexthop for |
| // unreachable routes, so nuke them. (IPv6 allows them to be specified; IPv4 doesn't.) |
| interface = OIF_NONE; |
| nexthop = NULL; |
| } else { |
| // If an interface was specified, find the ifindex. |
| if (interface != OIF_NONE) { |
| ifindex = if_nametoindex(interface); |
| if (!ifindex) { |
| ALOGE("cannot find interface %s", interface); |
| return -ENODEV; |
| } |
| } |
| |
| // If a nexthop was specified, parse it as the same family as the prefix. |
| if (nexthop && inet_pton(family, nexthop, rawNexthop) <= 0) { |
| ALOGE("inet_pton failed for nexthop %s", nexthop); |
| return -EINVAL; |
| } |
| } |
| |
| // Assemble a rtmsg and put it in an array of iovec structures. |
| rtmsg route = { |
| .rtm_protocol = RTPROT_STATIC, |
| .rtm_type = type, |
| .rtm_family = family, |
| .rtm_dst_len = prefixLength, |
| .rtm_scope = static_cast<uint8_t>(nexthop ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK), |
| }; |
| |
| rtattr rtaDst = { U16_RTA_LENGTH(rawLength), RTA_DST }; |
| rtattr rtaGateway = { U16_RTA_LENGTH(rawLength), RTA_GATEWAY }; |
| |
| iovec iov[] = { |
| { NULL, 0 }, |
| { &route, sizeof(route) }, |
| { &RTATTR_TABLE, sizeof(RTATTR_TABLE) }, |
| { &table, sizeof(table) }, |
| { &rtaDst, sizeof(rtaDst) }, |
| { rawAddress, static_cast<size_t>(rawLength) }, |
| { &RTATTR_OIF, interface != OIF_NONE ? sizeof(RTATTR_OIF) : 0 }, |
| { &ifindex, interface != OIF_NONE ? sizeof(ifindex) : 0 }, |
| { &rtaGateway, nexthop ? sizeof(rtaGateway) : 0 }, |
| { rawNexthop, nexthop ? static_cast<size_t>(rawLength) : 0 }, |
| }; |
| |
| uint16_t flags = (action == RTM_NEWROUTE) ? NETLINK_CREATE_REQUEST_FLAGS : |
| NETLINK_REQUEST_FLAGS; |
| return sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov)); |
| } |
| |
| // An iptables rule to mark incoming packets on a network with the netId of the network. |
| // |
| // This is so that the kernel can: |
| // + Use the right fwmark for (and thus correctly route) replies (e.g.: TCP RST, ICMP errors, ping |
| // replies, SYN-ACKs, etc). |
| // + Mark sockets that accept connections from this interface so that the connection stays on the |
| // same interface. |
| WARN_UNUSED_RESULT int modifyIncomingPacketMark(unsigned netId, const char* interface, |
| Permission permission, bool add) { |
| Fwmark fwmark; |
| |
| fwmark.netId = netId; |
| fwmark.explicitlySelected = true; |
| fwmark.protectedFromVpn = true; |
| fwmark.permission = permission; |
| |
| char markString[UINT32_HEX_STRLEN]; |
| snprintf(markString, sizeof(markString), "0x%x", fwmark.intValue); |
| |
| if (execIptables(V4V6, "-t", "mangle", add ? "-A" : "-D", "INPUT", "-i", interface, "-j", |
| "MARK", "--set-mark", markString, NULL)) { |
| ALOGE("failed to change iptables rule that sets incoming packet mark"); |
| return -EREMOTEIO; |
| } |
| |
| return 0; |
| } |
| |
| // A rule to route responses to the local network forwarded via the VPN. |
| // |
| // When a VPN is in effect, packets from the local network to upstream networks are forwarded into |
| // the VPN's tunnel interface. When the VPN forwards the responses, they emerge out of the tunnel. |
| WARN_UNUSED_RESULT int modifyVpnOutputToLocalRule(const char* vpnInterface, bool add) { |
| return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_VPN_OUTPUT_TO_LOCAL, |
| ROUTE_TABLE_LOCAL_NETWORK, MARK_UNSET, MARK_UNSET, vpnInterface, OIF_NONE, |
| INVALID_UID, INVALID_UID); |
| } |
| |
| // A rule to route all traffic from a given set of UIDs to go over the VPN. |
| // |
| // Notice that this rule doesn't use the netId. I.e., no matter what netId the user's socket may |
| // have, if they are subject to this VPN, their traffic has to go through it. Allows the traffic to |
| // bypass the VPN if the protectedFromVpn bit is set. |
| WARN_UNUSED_RESULT int modifyVpnUidRangeRule(uint32_t table, uid_t uidStart, uid_t uidEnd, |
| bool secure, bool add) { |
| Fwmark fwmark; |
| Fwmark mask; |
| |
| fwmark.protectedFromVpn = false; |
| mask.protectedFromVpn = true; |
| |
| uint32_t priority; |
| |
| if (secure) { |
| priority = RULE_PRIORITY_SECURE_VPN; |
| } else { |
| priority = RULE_PRIORITY_BYPASSABLE_VPN; |
| |
| fwmark.explicitlySelected = false; |
| mask.explicitlySelected = true; |
| } |
| |
| return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, priority, table, fwmark.intValue, |
| mask.intValue, IIF_NONE, OIF_NONE, uidStart, uidEnd); |
| } |
| |
| // A rule to allow system apps to send traffic over this VPN even if they are not part of the target |
| // set of UIDs. |
| // |
| // This is needed for DnsProxyListener to correctly resolve a request for a user who is in the |
| // target set, but where the DnsProxyListener itself is not. |
| WARN_UNUSED_RESULT int modifyVpnSystemPermissionRule(unsigned netId, uint32_t table, bool secure, |
| bool add) { |
| Fwmark fwmark; |
| Fwmark mask; |
| |
| fwmark.netId = netId; |
| mask.netId = FWMARK_NET_ID_MASK; |
| |
| fwmark.permission = PERMISSION_SYSTEM; |
| mask.permission = PERMISSION_SYSTEM; |
| |
| uint32_t priority = secure ? RULE_PRIORITY_SECURE_VPN : RULE_PRIORITY_BYPASSABLE_VPN; |
| |
| return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, priority, table, fwmark.intValue, |
| mask.intValue); |
| } |
| |
| // A rule to route traffic based on an explicitly chosen network. |
| // |
| // Supports apps that use the multinetwork APIs to restrict their traffic to a network. |
| // |
| // Even though we check permissions at the time we set a netId into the fwmark of a socket, we need |
| // to check it again in the rules here, because a network's permissions may have been updated via |
| // modifyNetworkPermission(). |
| WARN_UNUSED_RESULT int modifyExplicitNetworkRule(unsigned netId, uint32_t table, |
| Permission permission, uid_t uidStart, |
| uid_t uidEnd, bool add) { |
| Fwmark fwmark; |
| Fwmark mask; |
| |
| fwmark.netId = netId; |
| mask.netId = FWMARK_NET_ID_MASK; |
| |
| fwmark.explicitlySelected = true; |
| mask.explicitlySelected = true; |
| |
| fwmark.permission = permission; |
| mask.permission = permission; |
| |
| return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_EXPLICIT_NETWORK, table, |
| fwmark.intValue, mask.intValue, IIF_NONE, OIF_NONE, uidStart, uidEnd); |
| } |
| |
| // A rule to route traffic based on a chosen outgoing interface. |
| // |
| // Supports apps that use SO_BINDTODEVICE or IP_PKTINFO options and the kernel that already knows |
| // the outgoing interface (typically for link-local communications). |
| WARN_UNUSED_RESULT int modifyOutputInterfaceRule(const char* interface, uint32_t table, |
| Permission permission, uid_t uidStart, |
| uid_t uidEnd, bool add) { |
| Fwmark fwmark; |
| Fwmark mask; |
| |
| fwmark.permission = permission; |
| mask.permission = permission; |
| |
| return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_OUTPUT_INTERFACE, table, |
| fwmark.intValue, mask.intValue, IIF_NONE, interface, uidStart, uidEnd); |
| } |
| |
| // A rule to route traffic based on the chosen network. |
| // |
| // This is for sockets that have not explicitly requested a particular network, but have been |
| // bound to one when they called connect(). This ensures that sockets connected on a particular |
| // network stay on that network even if the default network changes. |
| WARN_UNUSED_RESULT int modifyImplicitNetworkRule(unsigned netId, uint32_t table, |
| Permission permission, bool add) { |
| Fwmark fwmark; |
| Fwmark mask; |
| |
| fwmark.netId = netId; |
| mask.netId = FWMARK_NET_ID_MASK; |
| |
| fwmark.explicitlySelected = false; |
| mask.explicitlySelected = true; |
| |
| fwmark.permission = permission; |
| mask.permission = permission; |
| |
| return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_IMPLICIT_NETWORK, table, |
| fwmark.intValue, mask.intValue); |
| } |
| |
| // A rule to enable split tunnel VPNs. |
| // |
| // If a packet with a VPN's netId doesn't find a route in the VPN's routing table, it's allowed to |
| // go over the default network, provided it wasn't explicitly restricted to the VPN and has the |
| // permissions required by the default network. |
| WARN_UNUSED_RESULT int modifyVpnFallthroughRule(uint16_t action, unsigned vpnNetId, |
| const char* physicalInterface, |
| Permission permission) { |
| uint32_t table = getRouteTableForInterface(physicalInterface); |
| if (table == RT_TABLE_UNSPEC) { |
| return -ESRCH; |
| } |
| |
| Fwmark fwmark; |
| Fwmark mask; |
| |
| fwmark.netId = vpnNetId; |
| mask.netId = FWMARK_NET_ID_MASK; |
| |
| fwmark.explicitlySelected = false; |
| mask.explicitlySelected = true; |
| |
| fwmark.permission = permission; |
| mask.permission = permission; |
| |
| return modifyIpRule(action, RULE_PRIORITY_VPN_FALLTHROUGH, table, fwmark.intValue, |
| mask.intValue); |
| } |
| |
| // Add rules to allow legacy routes added through the requestRouteToHost() API. |
| WARN_UNUSED_RESULT int addLegacyRouteRules() { |
| Fwmark fwmark; |
| Fwmark mask; |
| |
| fwmark.explicitlySelected = false; |
| mask.explicitlySelected = true; |
| |
| // Rules to allow legacy routes to override the default network. |
| if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LEGACY_SYSTEM, ROUTE_TABLE_LEGACY_SYSTEM, |
| fwmark.intValue, mask.intValue)) { |
| return ret; |
| } |
| if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LEGACY_NETWORK, |
| ROUTE_TABLE_LEGACY_NETWORK, fwmark.intValue, mask.intValue)) { |
| return ret; |
| } |
| |
| fwmark.permission = PERMISSION_SYSTEM; |
| mask.permission = PERMISSION_SYSTEM; |
| |
| // A rule to allow legacy routes from system apps to override VPNs. |
| return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_VPN_OVERRIDE_SYSTEM, ROUTE_TABLE_LEGACY_SYSTEM, |
| fwmark.intValue, mask.intValue); |
| } |
| |
| // Add rules to lookup the local network when specified explicitly or otherwise. |
| WARN_UNUSED_RESULT int addLocalNetworkRules(unsigned localNetId) { |
| if (int ret = modifyExplicitNetworkRule(localNetId, ROUTE_TABLE_LOCAL_NETWORK, PERMISSION_NONE, |
| INVALID_UID, INVALID_UID, ACTION_ADD)) { |
| return ret; |
| } |
| |
| Fwmark fwmark; |
| Fwmark mask; |
| |
| fwmark.explicitlySelected = false; |
| mask.explicitlySelected = true; |
| |
| return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LOCAL_NETWORK, ROUTE_TABLE_LOCAL_NETWORK, |
| fwmark.intValue, mask.intValue); |
| } |
| |
| // Add a new rule to look up the 'main' table, with the same selectors as the "default network" |
| // rule, but with a lower priority. We will never create routes in the main table; it should only be |
| // used for directly-connected routes implicitly created by the kernel when adding IP addresses. |
| // This is necessary, for example, when adding a route through a directly-connected gateway: in |
| // order to add the route, there must already be a directly-connected route that covers the gateway. |
| WARN_UNUSED_RESULT int addDirectlyConnectedRule() { |
| Fwmark fwmark; |
| Fwmark mask; |
| |
| fwmark.netId = NETID_UNSET; |
| mask.netId = FWMARK_NET_ID_MASK; |
| |
| return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_DIRECTLY_CONNECTED, RT_TABLE_MAIN, |
| fwmark.intValue, mask.intValue, IIF_NONE, OIF_NONE, UID_ROOT, UID_ROOT); |
| } |
| |
| // Add an explicit unreachable rule close to the end of the prioriy list to make it clear that |
| // relying on the kernel-default "from all lookup main" rule at priority 32766 is not intended |
| // behaviour. We do flush the kernel-default rules at startup, but having an explicit unreachable |
| // rule will hopefully make things even clearer. |
| WARN_UNUSED_RESULT int addUnreachableRule() { |
| return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_UNREACHABLE, RT_TABLE_UNSPEC, MARK_UNSET, |
| MARK_UNSET); |
| } |
| |
| WARN_UNUSED_RESULT int modifyLocalNetwork(unsigned netId, const char* interface, bool add) { |
| if (int ret = modifyIncomingPacketMark(netId, interface, PERMISSION_NONE, add)) { |
| return ret; |
| } |
| return modifyOutputInterfaceRule(interface, ROUTE_TABLE_LOCAL_NETWORK, PERMISSION_NONE, |
| INVALID_UID, INVALID_UID, add); |
| } |
| |
| WARN_UNUSED_RESULT int modifyPhysicalNetwork(unsigned netId, const char* interface, |
| Permission permission, bool add) { |
| uint32_t table = getRouteTableForInterface(interface); |
| if (table == RT_TABLE_UNSPEC) { |
| return -ESRCH; |
| } |
| |
| if (int ret = modifyIncomingPacketMark(netId, interface, permission, add)) { |
| return ret; |
| } |
| if (int ret = modifyExplicitNetworkRule(netId, table, permission, INVALID_UID, INVALID_UID, |
| add)) { |
| return ret; |
| } |
| if (int ret = modifyOutputInterfaceRule(interface, table, permission, INVALID_UID, INVALID_UID, |
| add)) { |
| return ret; |
| } |
| return modifyImplicitNetworkRule(netId, table, permission, add); |
| } |
| |
| WARN_UNUSED_RESULT int modifyVirtualNetwork(unsigned netId, const char* interface, |
| const UidRanges& uidRanges, bool secure, bool add, |
| bool modifyNonUidBasedRules) { |
| uint32_t table = getRouteTableForInterface(interface); |
| if (table == RT_TABLE_UNSPEC) { |
| return -ESRCH; |
| } |
| |
| for (const UidRanges::Range& range : uidRanges.getRanges()) { |
| if (int ret = modifyVpnUidRangeRule(table, range.first, range.second, secure, add)) { |
| return ret; |
| } |
| if (int ret = modifyExplicitNetworkRule(netId, table, PERMISSION_NONE, range.first, |
| range.second, add)) { |
| return ret; |
| } |
| if (int ret = modifyOutputInterfaceRule(interface, table, PERMISSION_NONE, range.first, |
| range.second, add)) { |
| return ret; |
| } |
| } |
| |
| if (modifyNonUidBasedRules) { |
| if (int ret = modifyIncomingPacketMark(netId, interface, PERMISSION_NONE, add)) { |
| return ret; |
| } |
| if (int ret = modifyVpnOutputToLocalRule(interface, add)) { |
| return ret; |
| } |
| if (int ret = modifyVpnSystemPermissionRule(netId, table, secure, add)) { |
| return ret; |
| } |
| return modifyExplicitNetworkRule(netId, table, PERMISSION_NONE, UID_ROOT, UID_ROOT, add); |
| } |
| |
| return 0; |
| } |
| |
| WARN_UNUSED_RESULT int modifyDefaultNetwork(uint16_t action, const char* interface, |
| Permission permission) { |
| uint32_t table = getRouteTableForInterface(interface); |
| if (table == RT_TABLE_UNSPEC) { |
| return -ESRCH; |
| } |
| |
| Fwmark fwmark; |
| Fwmark mask; |
| |
| fwmark.netId = NETID_UNSET; |
| mask.netId = FWMARK_NET_ID_MASK; |
| |
| fwmark.permission = permission; |
| mask.permission = permission; |
| |
| return modifyIpRule(action, RULE_PRIORITY_DEFAULT_NETWORK, table, fwmark.intValue, |
| mask.intValue); |
| } |
| |
| WARN_UNUSED_RESULT int modifyTetheredNetwork(uint16_t action, const char* inputInterface, |
| const char* outputInterface) { |
| uint32_t table = getRouteTableForInterface(outputInterface); |
| if (table == RT_TABLE_UNSPEC) { |
| return -ESRCH; |
| } |
| |
| return modifyIpRule(action, RULE_PRIORITY_TETHERING, table, MARK_UNSET, MARK_UNSET, |
| inputInterface, OIF_NONE, INVALID_UID, INVALID_UID); |
| } |
| |
| // Returns 0 on success or negative errno on failure. |
| WARN_UNUSED_RESULT int flushRules() { |
| for (size_t i = 0; i < ARRAY_SIZE(IP_VERSIONS); ++i) { |
| const char* argv[] = { |
| IP_PATH, |
| IP_VERSIONS[i], |
| "rule", |
| "flush", |
| }; |
| if (android_fork_execvp(ARRAY_SIZE(argv), const_cast<char**>(argv), NULL, false, false)) { |
| ALOGE("failed to flush rules"); |
| return -EREMOTEIO; |
| } |
| } |
| return 0; |
| } |
| |
| // Adds or removes an IPv4 or IPv6 route to the specified table and, if it's a directly-connected |
| // route, to the main table as well. |
| // Returns 0 on success or negative errno on failure. |
| WARN_UNUSED_RESULT int modifyRoute(uint16_t action, const char* interface, const char* destination, |
| const char* nexthop, RouteController::TableType tableType) { |
| uint32_t table; |
| switch (tableType) { |
| case RouteController::INTERFACE: { |
| table = getRouteTableForInterface(interface); |
| if (table == RT_TABLE_UNSPEC) { |
| return -ESRCH; |
| } |
| break; |
| } |
| case RouteController::LOCAL_NETWORK: { |
| table = ROUTE_TABLE_LOCAL_NETWORK; |
| break; |
| } |
| case RouteController::LEGACY_NETWORK: { |
| table = ROUTE_TABLE_LEGACY_NETWORK; |
| break; |
| } |
| case RouteController::LEGACY_SYSTEM: { |
| table = ROUTE_TABLE_LEGACY_SYSTEM; |
| break; |
| } |
| } |
| |
| int ret = modifyIpRoute(action, table, interface, destination, nexthop); |
| // We allow apps to call requestRouteToHost() multiple times with the same route, so ignore |
| // EEXIST failures when adding routes to legacy tables. |
| if (ret && !(action == RTM_NEWROUTE && ret == -EEXIST && |
| (tableType == RouteController::LEGACY_NETWORK || |
| tableType == RouteController::LEGACY_SYSTEM))) { |
| return ret; |
| } |
| |
| return 0; |
| } |
| |
| // Returns 0 on success or negative errno on failure. |
| WARN_UNUSED_RESULT int flushRoutes(const char* interface) { |
| uint32_t table = getRouteTableForInterface(interface); |
| if (table == RT_TABLE_UNSPEC) { |
| return -ESRCH; |
| } |
| |
| char tableString[UINT32_STRLEN]; |
| snprintf(tableString, sizeof(tableString), "%u", table); |
| |
| for (size_t i = 0; i < ARRAY_SIZE(IP_VERSIONS); ++i) { |
| const char* argv[] = { |
| IP_PATH, |
| IP_VERSIONS[i], |
| "route", |
| "flush", |
| "table", |
| tableString, |
| }; |
| if (android_fork_execvp(ARRAY_SIZE(argv), const_cast<char**>(argv), NULL, false, false)) { |
| ALOGE("failed to flush routes"); |
| return -EREMOTEIO; |
| } |
| } |
| |
| interfaceToTable.erase(interface); |
| return 0; |
| } |
| |
| } // namespace |
| |
| int RouteController::Init(unsigned localNetId) { |
| if (int ret = flushRules()) { |
| return ret; |
| } |
| if (int ret = addLegacyRouteRules()) { |
| return ret; |
| } |
| if (int ret = addLocalNetworkRules(localNetId)) { |
| return ret; |
| } |
| if (int ret = addDirectlyConnectedRule()) { |
| return ret; |
| } |
| if (int ret = addUnreachableRule()) { |
| return ret; |
| } |
| updateTableNamesFile(); |
| return 0; |
| } |
| |
| int RouteController::addInterfaceToLocalNetwork(unsigned netId, const char* interface) { |
| return modifyLocalNetwork(netId, interface, ACTION_ADD); |
| } |
| |
| int RouteController::removeInterfaceFromLocalNetwork(unsigned netId, const char* interface) { |
| return modifyLocalNetwork(netId, interface, ACTION_DEL); |
| } |
| |
| int RouteController::addInterfaceToPhysicalNetwork(unsigned netId, const char* interface, |
| Permission permission) { |
| if (int ret = modifyPhysicalNetwork(netId, interface, permission, ACTION_ADD)) { |
| return ret; |
| } |
| updateTableNamesFile(); |
| return 0; |
| } |
| |
| int RouteController::removeInterfaceFromPhysicalNetwork(unsigned netId, const char* interface, |
| Permission permission) { |
| if (int ret = modifyPhysicalNetwork(netId, interface, permission, ACTION_DEL)) { |
| return ret; |
| } |
| if (int ret = flushRoutes(interface)) { |
| return ret; |
| } |
| updateTableNamesFile(); |
| return 0; |
| } |
| |
| int RouteController::addInterfaceToVirtualNetwork(unsigned netId, const char* interface, |
| bool secure, const UidRanges& uidRanges) { |
| if (int ret = modifyVirtualNetwork(netId, interface, uidRanges, secure, ACTION_ADD, |
| MODIFY_NON_UID_BASED_RULES)) { |
| return ret; |
| } |
| updateTableNamesFile(); |
| return 0; |
| } |
| |
| int RouteController::removeInterfaceFromVirtualNetwork(unsigned netId, const char* interface, |
| bool secure, const UidRanges& uidRanges) { |
| if (int ret = modifyVirtualNetwork(netId, interface, uidRanges, secure, ACTION_DEL, |
| MODIFY_NON_UID_BASED_RULES)) { |
| return ret; |
| } |
| if (int ret = flushRoutes(interface)) { |
| return ret; |
| } |
| updateTableNamesFile(); |
| return 0; |
| } |
| |
| int RouteController::modifyPhysicalNetworkPermission(unsigned netId, const char* interface, |
| Permission oldPermission, |
| Permission newPermission) { |
| // Add the new rules before deleting the old ones, to avoid race conditions. |
| if (int ret = modifyPhysicalNetwork(netId, interface, newPermission, ACTION_ADD)) { |
| return ret; |
| } |
| return modifyPhysicalNetwork(netId, interface, oldPermission, ACTION_DEL); |
| } |
| |
| int RouteController::addUsersToVirtualNetwork(unsigned netId, const char* interface, bool secure, |
| const UidRanges& uidRanges) { |
| return modifyVirtualNetwork(netId, interface, uidRanges, secure, ACTION_ADD, |
| !MODIFY_NON_UID_BASED_RULES); |
| } |
| |
| int RouteController::removeUsersFromVirtualNetwork(unsigned netId, const char* interface, |
| bool secure, const UidRanges& uidRanges) { |
| return modifyVirtualNetwork(netId, interface, uidRanges, secure, ACTION_DEL, |
| !MODIFY_NON_UID_BASED_RULES); |
| } |
| |
| int RouteController::addInterfaceToDefaultNetwork(const char* interface, Permission permission) { |
| return modifyDefaultNetwork(RTM_NEWRULE, interface, permission); |
| } |
| |
| int RouteController::removeInterfaceFromDefaultNetwork(const char* interface, |
| Permission permission) { |
| return modifyDefaultNetwork(RTM_DELRULE, interface, permission); |
| } |
| |
| int RouteController::addRoute(const char* interface, const char* destination, const char* nexthop, |
| TableType tableType) { |
| return modifyRoute(RTM_NEWROUTE, interface, destination, nexthop, tableType); |
| } |
| |
| int RouteController::removeRoute(const char* interface, const char* destination, |
| const char* nexthop, TableType tableType) { |
| return modifyRoute(RTM_DELROUTE, interface, destination, nexthop, tableType); |
| } |
| |
| int RouteController::enableTethering(const char* inputInterface, const char* outputInterface) { |
| return modifyTetheredNetwork(RTM_NEWRULE, inputInterface, outputInterface); |
| } |
| |
| int RouteController::disableTethering(const char* inputInterface, const char* outputInterface) { |
| return modifyTetheredNetwork(RTM_DELRULE, inputInterface, outputInterface); |
| } |
| |
| int RouteController::addVirtualNetworkFallthrough(unsigned vpnNetId, const char* physicalInterface, |
| Permission permission) { |
| return modifyVpnFallthroughRule(RTM_NEWRULE, vpnNetId, physicalInterface, permission); |
| } |
| |
| int RouteController::removeVirtualNetworkFallthrough(unsigned vpnNetId, |
| const char* physicalInterface, |
| Permission permission) { |
| return modifyVpnFallthroughRule(RTM_DELRULE, vpnNetId, physicalInterface, permission); |
| } |