| /* |
| * Copyright (C) 2012 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 <errno.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #define LOG_TAG "FirewallController" |
| #define LOG_NDEBUG 0 |
| |
| #include <android-base/stringprintf.h> |
| #include <cutils/log.h> |
| |
| #include "NetdConstants.h" |
| #include "FirewallController.h" |
| |
| using android::base::StringAppendF; |
| |
| auto FirewallController::execIptables = ::execIptables; |
| auto FirewallController::execIptablesSilently = ::execIptablesSilently; |
| auto FirewallController::execIptablesRestore = ::execIptablesRestore; |
| |
| const char* FirewallController::TABLE = "filter"; |
| |
| const char* FirewallController::LOCAL_INPUT = "fw_INPUT"; |
| const char* FirewallController::LOCAL_OUTPUT = "fw_OUTPUT"; |
| const char* FirewallController::LOCAL_FORWARD = "fw_FORWARD"; |
| |
| const char* FirewallController::LOCAL_DOZABLE = "fw_dozable"; |
| const char* FirewallController::LOCAL_STANDBY = "fw_standby"; |
| const char* FirewallController::LOCAL_POWERSAVE = "fw_powersave"; |
| |
| // ICMPv6 types that are required for any form of IPv6 connectivity to work. Note that because the |
| // fw_dozable chain is called from both INPUT and OUTPUT, this includes both packets that we need |
| // to be able to send (e.g., RS, NS), and packets that we need to receive (e.g., RA, NA). |
| const char* FirewallController::ICMPV6_TYPES[] = { |
| "packet-too-big", |
| "router-solicitation", |
| "router-advertisement", |
| "neighbour-solicitation", |
| "neighbour-advertisement", |
| "redirect", |
| }; |
| |
| FirewallController::FirewallController(void) { |
| // If no rules are set, it's in BLACKLIST mode |
| mFirewallType = BLACKLIST; |
| } |
| |
| int FirewallController::setupIptablesHooks(void) { |
| int res = 0; |
| res |= createChain(LOCAL_DOZABLE, getFirewallType(DOZABLE)); |
| res |= createChain(LOCAL_STANDBY, getFirewallType(STANDBY)); |
| res |= createChain(LOCAL_POWERSAVE, getFirewallType(POWERSAVE)); |
| return res; |
| } |
| |
| int FirewallController::enableFirewall(FirewallType ftype) { |
| int res = 0; |
| if (mFirewallType != ftype) { |
| // flush any existing rules |
| disableFirewall(); |
| |
| if (ftype == WHITELIST) { |
| // create default rule to drop all traffic |
| res |= execIptables(V4V6, "-A", LOCAL_INPUT, "-j", "DROP", NULL); |
| res |= execIptables(V4V6, "-A", LOCAL_OUTPUT, "-j", "REJECT", NULL); |
| res |= execIptables(V4V6, "-A", LOCAL_FORWARD, "-j", "REJECT", NULL); |
| } |
| |
| // Set this after calling disableFirewall(), since it defaults to WHITELIST there |
| mFirewallType = ftype; |
| } |
| return res; |
| } |
| |
| int FirewallController::disableFirewall(void) { |
| int res = 0; |
| |
| mFirewallType = WHITELIST; |
| |
| // flush any existing rules |
| res |= execIptables(V4V6, "-F", LOCAL_INPUT, NULL); |
| res |= execIptables(V4V6, "-F", LOCAL_OUTPUT, NULL); |
| res |= execIptables(V4V6, "-F", LOCAL_FORWARD, NULL); |
| |
| return res; |
| } |
| |
| int FirewallController::enableChildChains(ChildChain chain, bool enable) { |
| int res = 0; |
| const char* name; |
| switch(chain) { |
| case DOZABLE: |
| name = LOCAL_DOZABLE; |
| break; |
| case STANDBY: |
| name = LOCAL_STANDBY; |
| break; |
| case POWERSAVE: |
| name = LOCAL_POWERSAVE; |
| break; |
| default: |
| return res; |
| } |
| |
| std::string command = "*filter\n"; |
| for (const char *parent : { LOCAL_INPUT, LOCAL_OUTPUT }) { |
| StringAppendF(&command, "%s %s -j %s\n", (enable ? "-A" : "-D"), parent, name); |
| } |
| StringAppendF(&command, "COMMIT\n"); |
| |
| return execIptablesRestore(V4V6, command); |
| } |
| |
| int FirewallController::isFirewallEnabled(void) { |
| // TODO: verify that rules are still in place near top |
| return -1; |
| } |
| |
| int FirewallController::setInterfaceRule(const char* iface, FirewallRule rule) { |
| if (mFirewallType == BLACKLIST) { |
| // Unsupported in BLACKLIST mode |
| return -1; |
| } |
| |
| if (!isIfaceName(iface)) { |
| errno = ENOENT; |
| return -1; |
| } |
| |
| const char* op; |
| if (rule == ALLOW) { |
| op = "-I"; |
| } else { |
| op = "-D"; |
| } |
| |
| int res = 0; |
| res |= execIptables(V4V6, op, LOCAL_INPUT, "-i", iface, "-j", "RETURN", NULL); |
| res |= execIptables(V4V6, op, LOCAL_OUTPUT, "-o", iface, "-j", "RETURN", NULL); |
| return res; |
| } |
| |
| int FirewallController::setEgressSourceRule(const char* addr, FirewallRule rule) { |
| if (mFirewallType == BLACKLIST) { |
| // Unsupported in BLACKLIST mode |
| return -1; |
| } |
| |
| IptablesTarget target = V4; |
| if (strchr(addr, ':')) { |
| target = V6; |
| } |
| |
| const char* op; |
| if (rule == ALLOW) { |
| op = "-I"; |
| } else { |
| op = "-D"; |
| } |
| |
| int res = 0; |
| res |= execIptables(target, op, LOCAL_INPUT, "-d", addr, "-j", "RETURN", NULL); |
| res |= execIptables(target, op, LOCAL_OUTPUT, "-s", addr, "-j", "RETURN", NULL); |
| return res; |
| } |
| |
| int FirewallController::setEgressDestRule(const char* addr, int protocol, int port, |
| FirewallRule rule) { |
| if (mFirewallType == BLACKLIST) { |
| // Unsupported in BLACKLIST mode |
| return -1; |
| } |
| |
| IptablesTarget target = V4; |
| if (strchr(addr, ':')) { |
| target = V6; |
| } |
| |
| char protocolStr[16]; |
| sprintf(protocolStr, "%d", protocol); |
| |
| char portStr[16]; |
| sprintf(portStr, "%d", port); |
| |
| const char* op; |
| if (rule == ALLOW) { |
| op = "-I"; |
| } else { |
| op = "-D"; |
| } |
| |
| int res = 0; |
| res |= execIptables(target, op, LOCAL_INPUT, "-s", addr, "-p", protocolStr, |
| "--sport", portStr, "-j", "RETURN", NULL); |
| res |= execIptables(target, op, LOCAL_OUTPUT, "-d", addr, "-p", protocolStr, |
| "--dport", portStr, "-j", "RETURN", NULL); |
| return res; |
| } |
| |
| FirewallType FirewallController::getFirewallType(ChildChain chain) { |
| switch(chain) { |
| case DOZABLE: |
| return WHITELIST; |
| case STANDBY: |
| return BLACKLIST; |
| case POWERSAVE: |
| return WHITELIST; |
| case NONE: |
| return mFirewallType; |
| default: |
| return BLACKLIST; |
| } |
| } |
| |
| int FirewallController::setUidRule(ChildChain chain, int uid, FirewallRule rule) { |
| const char* op; |
| const char* target; |
| FirewallType firewallType = getFirewallType(chain); |
| if (firewallType == WHITELIST) { |
| target = "RETURN"; |
| // When adding, insert RETURN rules at the front, before the catch-all DROP at the end. |
| op = (rule == ALLOW)? "-I" : "-D"; |
| } else { // BLACKLIST mode |
| target = "DROP"; |
| // When adding, append DROP rules at the end, after the RETURN rule that matches TCP RSTs. |
| op = (rule == DENY)? "-A" : "-D"; |
| } |
| |
| std::vector<std::string> chainNames; |
| switch(chain) { |
| case DOZABLE: |
| chainNames = { LOCAL_DOZABLE }; |
| break; |
| case STANDBY: |
| chainNames = { LOCAL_STANDBY }; |
| break; |
| case POWERSAVE: |
| chainNames = { LOCAL_POWERSAVE }; |
| break; |
| case NONE: |
| chainNames = { LOCAL_INPUT, LOCAL_OUTPUT }; |
| break; |
| default: |
| ALOGW("Unknown child chain: %d", chain); |
| return -1; |
| } |
| |
| std::string command = "*filter\n"; |
| for (std::string chainName : chainNames) { |
| StringAppendF(&command, "%s %s -m owner --uid-owner %d -j %s\n", |
| op, chainName.c_str(), uid, target); |
| } |
| StringAppendF(&command, "COMMIT\n"); |
| |
| return execIptablesRestore(V4V6, command); |
| } |
| |
| int FirewallController::createChain(const char* chain, FirewallType type) { |
| static const std::vector<int32_t> NO_UIDS; |
| return replaceUidChain(chain, type == WHITELIST, NO_UIDS); |
| } |
| |
| std::string FirewallController::makeUidRules(IptablesTarget target, const char *name, |
| bool isWhitelist, const std::vector<int32_t>& uids) { |
| std::string commands; |
| StringAppendF(&commands, "*filter\n:%s -\n", name); |
| |
| // Whitelist chains have UIDs at the beginning, and new UIDs are added with '-I'. |
| if (isWhitelist) { |
| for (auto uid : uids) { |
| StringAppendF(&commands, "-A %s -m owner --uid-owner %d -j RETURN\n", name, uid); |
| } |
| |
| // Always whitelist system UIDs. |
| StringAppendF(&commands, |
| "-A %s -m owner --uid-owner %d-%d -j RETURN\n", name, 0, MAX_SYSTEM_UID); |
| } |
| |
| // Always allow networking on loopback. |
| StringAppendF(&commands, "-A %s -i lo -j RETURN\n", name); |
| StringAppendF(&commands, "-A %s -o lo -j RETURN\n", name); |
| |
| // Allow TCP RSTs so we can cleanly close TCP connections of apps that no longer have network |
| // access. Both incoming and outgoing RSTs are allowed. |
| StringAppendF(&commands, "-A %s -p tcp --tcp-flags RST RST -j RETURN\n", name); |
| |
| if (isWhitelist) { |
| // Allow ICMPv6 packets necessary to make IPv6 connectivity work. http://b/23158230 . |
| if (target == V6) { |
| for (size_t i = 0; i < ARRAY_SIZE(ICMPV6_TYPES); i++) { |
| StringAppendF(&commands, "-A %s -p icmpv6 --icmpv6-type %s -j RETURN\n", |
| name, ICMPV6_TYPES[i]); |
| } |
| } |
| } |
| |
| // Blacklist chains have UIDs at the end, and new UIDs are added with '-A'. |
| if (!isWhitelist) { |
| for (auto uid : uids) { |
| StringAppendF(&commands, "-A %s -m owner --uid-owner %d -j DROP\n", name, uid); |
| } |
| } |
| |
| // If it's a whitelist chain, add a default DROP at the end. This is not necessary for a |
| // blacklist chain, because all user-defined chains implicitly RETURN at the end. |
| if (isWhitelist) { |
| StringAppendF(&commands, "-A %s -j DROP\n", name); |
| } |
| |
| StringAppendF(&commands, "COMMIT\n"); |
| |
| return commands; |
| } |
| |
| int FirewallController::replaceUidChain( |
| const char *name, bool isWhitelist, const std::vector<int32_t>& uids) { |
| std::string commands4 = makeUidRules(V4, name, isWhitelist, uids); |
| std::string commands6 = makeUidRules(V6, name, isWhitelist, uids); |
| return execIptablesRestore(V4, commands4.c_str()) | execIptablesRestore(V6, commands6.c_str()); |
| } |