| /* |
| * 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 <set> |
| |
| #include <errno.h> |
| #include <limits.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <cstdint> |
| |
| #define LOG_TAG "FirewallController" |
| #define LOG_NDEBUG 0 |
| |
| #include <android-base/file.h> |
| #include <android-base/stringprintf.h> |
| #include <android-base/strings.h> |
| #include <log/log.h> |
| |
| #include "Controllers.h" |
| #include "FirewallController.h" |
| #include "NetdConstants.h" |
| #include "bpf/BpfUtils.h" |
| |
| using android::base::Join; |
| using android::base::StringAppendF; |
| using android::base::StringPrintf; |
| |
| namespace android { |
| namespace net { |
| |
| 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"; |
| |
| // 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 DENYLIST mode |
| mFirewallType = DENYLIST; |
| mIfaceRules = {}; |
| } |
| |
| int FirewallController::setupIptablesHooks(void) { |
| return flushRules(); |
| } |
| |
| int FirewallController::setFirewallType(FirewallType ftype) { |
| int res = 0; |
| if (mFirewallType != ftype) { |
| // flush any existing rules |
| resetFirewall(); |
| |
| if (ftype == ALLOWLIST) { |
| // create default rule to drop all traffic |
| std::string command = |
| "*filter\n" |
| "-A fw_INPUT -j DROP\n" |
| "-A fw_OUTPUT -j REJECT\n" |
| "-A fw_FORWARD -j REJECT\n" |
| "COMMIT\n"; |
| res = execIptablesRestore(V4V6, command.c_str()); |
| } |
| |
| // Set this after calling disableFirewall(), since it defaults to ALLOWLIST there |
| mFirewallType = ftype; |
| } |
| return res ? -EREMOTEIO : 0; |
| } |
| |
| int FirewallController::flushRules() { |
| std::string command = |
| "*filter\n" |
| ":fw_INPUT -\n" |
| ":fw_OUTPUT -\n" |
| ":fw_FORWARD -\n" |
| "-6 -A fw_OUTPUT ! -o lo -s ::1 -j DROP\n" |
| "COMMIT\n"; |
| |
| return (execIptablesRestore(V4V6, command.c_str()) == 0) ? 0 : -EREMOTEIO; |
| } |
| |
| int FirewallController::resetFirewall(void) { |
| mFirewallType = ALLOWLIST; |
| mIfaceRules.clear(); |
| return flushRules(); |
| } |
| |
| 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 == DENYLIST) { |
| // Unsupported in DENYLIST mode |
| return -EINVAL; |
| } |
| |
| if (!isIfaceName(iface)) { |
| errno = ENOENT; |
| return -ENOENT; |
| } |
| |
| // Only delete rules if we actually added them, because otherwise our iptables-restore |
| // processes will terminate with "no such rule" errors and cause latency penalties while we |
| // spin up new ones. |
| const char* op; |
| if (rule == ALLOW && mIfaceRules.find(iface) == mIfaceRules.end()) { |
| op = "-I"; |
| mIfaceRules.insert(iface); |
| } else if (rule == DENY && mIfaceRules.find(iface) != mIfaceRules.end()) { |
| op = "-D"; |
| mIfaceRules.erase(iface); |
| } else { |
| return 0; |
| } |
| |
| std::string command = Join(std::vector<std::string> { |
| "*filter", |
| StringPrintf("%s fw_INPUT -i %s -j RETURN", op, iface), |
| StringPrintf("%s fw_OUTPUT -o %s -j RETURN", op, iface), |
| "COMMIT\n" |
| }, "\n"); |
| return (execIptablesRestore(V4V6, command) == 0) ? 0 : -EREMOTEIO; |
| } |
| |
| /* static */ |
| std::string FirewallController::makeCriticalCommands(IptablesTarget target, const char* chainName) { |
| // Allow ICMPv6 packets necessary to make IPv6 connectivity work. http://b/23158230 . |
| std::string commands; |
| 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", |
| chainName, ICMPV6_TYPES[i]); |
| } |
| } |
| return commands; |
| } |
| |
| } // namespace net |
| } // namespace android |