/*
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* Copyright (C) 2012 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef _FIREWALL_CONTROLLER_H
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#define _FIREWALL_CONTROLLER_H
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#include <sys/types.h>
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#include <mutex>
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#include <set>
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#include <string>
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#include <vector>
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#include "android/net/INetd.h"
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#include "NetdConstants.h"
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#include "bpf/BpfUtils.h"
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namespace android {
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namespace net {
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enum FirewallRule { ALLOW = INetd::FIREWALL_RULE_ALLOW, DENY = INetd::FIREWALL_RULE_DENY };
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// WHITELIST means the firewall denies all by default, uids must be explicitly ALLOWed
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// BLACKLIST means the firewall allows all by default, uids must be explicitly DENYed
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enum FirewallType { WHITELIST = INetd::FIREWALL_WHITELIST, BLACKLIST = INetd::FIREWALL_BLACKLIST };
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enum ChildChain {
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NONE = INetd::FIREWALL_CHAIN_NONE,
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DOZABLE = INetd::FIREWALL_CHAIN_DOZABLE,
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STANDBY = INetd::FIREWALL_CHAIN_STANDBY,
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POWERSAVE = INetd::FIREWALL_CHAIN_POWERSAVE,
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INVALID_CHAIN
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};
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/*
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* Simple firewall that drops all packets except those matching explicitly
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* defined ALLOW rules.
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*
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* Methods in this class must be called when holding a write lock on |lock|, and may not call
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* any other controller without explicitly managing that controller's lock. There are currently
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* no such methods.
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*/
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class FirewallController {
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public:
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FirewallController();
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int setupIptablesHooks(void);
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int setFirewallType(FirewallType);
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int resetFirewall(void);
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int isFirewallEnabled(void);
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/* Match traffic going in/out over the given iface. */
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int setInterfaceRule(const char*, FirewallRule);
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/* Match traffic owned by given UID. This is specific to a particular chain. */
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int setUidRule(ChildChain, int, FirewallRule);
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int enableChildChains(ChildChain, bool);
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int replaceUidChain(const std::string&, bool, const std::vector<int32_t>&);
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static std::string makeCriticalCommands(IptablesTarget target, const char* chainName);
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static uid_t discoverMaximumValidUid(const std::string& fileName);
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static const char* TABLE;
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static const char* LOCAL_INPUT;
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static const char* LOCAL_OUTPUT;
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static const char* LOCAL_FORWARD;
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static const char* LOCAL_DOZABLE;
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static const char* LOCAL_STANDBY;
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static const char* LOCAL_POWERSAVE;
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static const char* ICMPV6_TYPES[];
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std::mutex lock;
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protected:
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friend class FirewallControllerTest;
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std::string makeUidRules(IptablesTarget target, const char *name, bool isWhitelist,
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const std::vector<int32_t>& uids);
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static int (*execIptablesRestore)(IptablesTarget target, const std::string& commands);
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private:
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// Netd supports two cases, in both of which mMaxUid that derives from the uid mapping is const:
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// - netd runs in a root namespace which contains all UIDs.
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// - netd runs in a user namespace where the uid mapping is written once before netd starts.
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// In that case, an attempt to write more than once to a uid_map file in a user namespace
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// fails with EPERM. Netd can therefore assumes the max valid uid to be const.
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const uid_t mMaxUid;
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FirewallType mFirewallType;
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android::bpf::BpfLevel mUseBpfOwnerMatch;
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std::set<std::string> mIfaceRules;
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int attachChain(const char*, const char*);
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int detachChain(const char*, const char*);
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int createChain(const char*, FirewallType);
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FirewallType getFirewallType(ChildChain);
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};
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} // namespace net
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} // namespace android
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#endif
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