Luke Huang | 403c044 | 2019-02-25 15:33:42 +0800 | [diff] [blame] | 1 | /** |
| 2 | * Copyright (c) 2019, 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 | #define LOG_TAG "DnsResolverService" |
| 18 | |
Luke Huang | 36796f3 | 2019-03-13 02:54:45 +0800 | [diff] [blame] | 19 | #include "DnsResolverService.h" |
| 20 | |
Luke Huang | 403c044 | 2019-02-25 15:33:42 +0800 | [diff] [blame] | 21 | #include <set> |
| 22 | #include <vector> |
| 23 | |
| 24 | #include <android-base/stringprintf.h> |
| 25 | #include <android-base/strings.h> |
| 26 | #include <android/binder_manager.h> |
| 27 | #include <android/binder_process.h> |
| 28 | #include <log/log.h> |
Luke Huang | 7b26b20 | 2019-03-28 14:09:24 +0800 | [diff] [blame] | 29 | #include <openssl/base64.h> |
Luke Huang | 403c044 | 2019-02-25 15:33:42 +0800 | [diff] [blame] | 30 | #include <private/android_filesystem_config.h> // AID_SYSTEM |
| 31 | |
Luke Huang | 36796f3 | 2019-03-13 02:54:45 +0800 | [diff] [blame] | 32 | #include "DnsResolver.h" |
Luke Huang | 7b26b20 | 2019-03-28 14:09:24 +0800 | [diff] [blame] | 33 | #include "NetdConstants.h" // SHA256_SIZE |
Luke Huang | 403c044 | 2019-02-25 15:33:42 +0800 | [diff] [blame] | 34 | #include "NetdPermissions.h" // PERM_* |
Hungming Chen | a32c8c1 | 2019-01-25 10:47:40 +0800 | [diff] [blame] | 35 | #include "ResolverEventReporter.h" |
Luke Huang | 7b26b20 | 2019-03-28 14:09:24 +0800 | [diff] [blame] | 36 | #include "netdutils/DumpWriter.h" |
Luke Huang | 403c044 | 2019-02-25 15:33:42 +0800 | [diff] [blame] | 37 | |
| 38 | using android::base::Join; |
| 39 | using android::base::StringPrintf; |
Luke Huang | 7b26b20 | 2019-03-28 14:09:24 +0800 | [diff] [blame] | 40 | using android::netdutils::DumpWriter; |
Luke Huang | 403c044 | 2019-02-25 15:33:42 +0800 | [diff] [blame] | 41 | |
| 42 | namespace android { |
| 43 | namespace net { |
| 44 | |
| 45 | namespace { |
| 46 | |
| 47 | #define ENFORCE_ANY_PERMISSION(...) \ |
| 48 | do { \ |
| 49 | ::ndk::ScopedAStatus status = checkAnyPermission({__VA_ARGS__}); \ |
| 50 | if (!status.isOk()) { \ |
| 51 | return status; \ |
| 52 | } \ |
| 53 | } while (0) |
| 54 | |
| 55 | #define ENFORCE_INTERNAL_PERMISSIONS() \ |
| 56 | ENFORCE_ANY_PERMISSION(PERM_CONNECTIVITY_INTERNAL, PERM_MAINLINE_NETWORK_STACK) |
| 57 | |
| 58 | #define ENFORCE_NETWORK_STACK_PERMISSIONS() \ |
| 59 | ENFORCE_ANY_PERMISSION(PERM_NETWORK_STACK, PERM_MAINLINE_NETWORK_STACK) |
| 60 | |
Hungming Chen | a32c8c1 | 2019-01-25 10:47:40 +0800 | [diff] [blame] | 61 | inline ::ndk::ScopedAStatus statusFromErrcode(int ret) { |
| 62 | if (ret) { |
| 63 | return ::ndk::ScopedAStatus( |
| 64 | AStatus_fromServiceSpecificErrorWithMessage(-ret, strerror(-ret))); |
| 65 | } |
| 66 | return ::ndk::ScopedAStatus(AStatus_newOk()); |
| 67 | } |
| 68 | |
Luke Huang | 403c044 | 2019-02-25 15:33:42 +0800 | [diff] [blame] | 69 | } // namespace |
| 70 | |
Luke Huang | 36796f3 | 2019-03-13 02:54:45 +0800 | [diff] [blame] | 71 | binder_status_t DnsResolverService::start() { |
Luke Huang | 403c044 | 2019-02-25 15:33:42 +0800 | [diff] [blame] | 72 | // TODO: Add disableBackgroundScheduling(true) after libbinder_ndk support it. b/126506010 |
| 73 | // NetdNativeService does call disableBackgroundScheduling currently, so it is fine now. |
Luke Huang | 36796f3 | 2019-03-13 02:54:45 +0800 | [diff] [blame] | 74 | DnsResolverService* resolverService = new DnsResolverService(); |
Luke Huang | 403c044 | 2019-02-25 15:33:42 +0800 | [diff] [blame] | 75 | binder_status_t status = |
| 76 | AServiceManager_addService(resolverService->asBinder().get(), getServiceName()); |
| 77 | if (status != STATUS_OK) { |
| 78 | return status; |
| 79 | } |
| 80 | |
| 81 | ABinderProcess_startThreadPool(); |
| 82 | |
| 83 | // TODO: register log callback if binder NDK backend support it. b/126501406 |
| 84 | |
| 85 | return STATUS_OK; |
| 86 | } |
| 87 | |
Luke Huang | 7b26b20 | 2019-03-28 14:09:24 +0800 | [diff] [blame] | 88 | binder_status_t DnsResolverService::dump(int, const char**, uint32_t) { |
| 89 | // TODO: Implement it. Netd binder dump resolver related log based on all stored network. |
| 90 | // However, resolver doesn't know that informations. |
| 91 | return STATUS_OK; |
| 92 | } |
| 93 | |
Luke Huang | 403c044 | 2019-02-25 15:33:42 +0800 | [diff] [blame] | 94 | ::ndk::ScopedAStatus DnsResolverService::isAlive(bool* alive) { |
| 95 | ENFORCE_INTERNAL_PERMISSIONS(); |
| 96 | |
| 97 | *alive = true; |
| 98 | |
| 99 | return ::ndk::ScopedAStatus(AStatus_newOk()); |
| 100 | } |
| 101 | |
Hungming Chen | a32c8c1 | 2019-01-25 10:47:40 +0800 | [diff] [blame] | 102 | ::ndk::ScopedAStatus DnsResolverService::registerEventListener( |
| 103 | const std::shared_ptr<aidl::android::net::metrics::INetdEventListener>& listener) { |
| 104 | ENFORCE_NETWORK_STACK_PERMISSIONS(); |
| 105 | |
| 106 | int res = ResolverEventReporter::getInstance().addListener(listener); |
| 107 | |
| 108 | return statusFromErrcode(res); |
| 109 | } |
| 110 | |
Luke Huang | 403c044 | 2019-02-25 15:33:42 +0800 | [diff] [blame] | 111 | ::ndk::ScopedAStatus DnsResolverService::checkAnyPermission( |
| 112 | const std::vector<const char*>& permissions) { |
| 113 | // TODO: Remove callback and move this to unnamed namespace after libbiner_ndk supports |
| 114 | // check_permission. |
Luke Huang | 36796f3 | 2019-03-13 02:54:45 +0800 | [diff] [blame] | 115 | if (!gResNetdCallbacks.check_calling_permission) { |
Luke Huang | 403c044 | 2019-02-25 15:33:42 +0800 | [diff] [blame] | 116 | return ::ndk::ScopedAStatus(AStatus_fromExceptionCodeWithMessage( |
| 117 | EX_NULL_POINTER, "check_calling_permission is null")); |
| 118 | } |
| 119 | pid_t pid = AIBinder_getCallingPid(); |
| 120 | uid_t uid = AIBinder_getCallingUid(); |
| 121 | |
| 122 | // If the caller is the system UID, don't check permissions. |
| 123 | // Otherwise, if the system server's binder thread pool is full, and all the threads are |
| 124 | // blocked on a thread that's waiting for us to complete, we deadlock. http://b/69389492 |
| 125 | // |
| 126 | // From a security perspective, there is currently no difference, because: |
| 127 | // 1. The only permissions we check in netd's binder interface are CONNECTIVITY_INTERNAL |
| 128 | // and NETWORK_STACK, which the system server always has (or MAINLINE_NETWORK_STACK, which |
| 129 | // is equivalent to having both CONNECTIVITY_INTERNAL and NETWORK_STACK). |
| 130 | // 2. AID_SYSTEM always has all permissions. See ActivityManager#checkComponentPermission. |
| 131 | if (uid == AID_SYSTEM) { |
| 132 | return ::ndk::ScopedAStatus(AStatus_newOk()); |
| 133 | } |
| 134 | |
| 135 | for (const char* permission : permissions) { |
Luke Huang | 36796f3 | 2019-03-13 02:54:45 +0800 | [diff] [blame] | 136 | if (gResNetdCallbacks.check_calling_permission(permission)) { |
Luke Huang | 403c044 | 2019-02-25 15:33:42 +0800 | [diff] [blame] | 137 | return ::ndk::ScopedAStatus(AStatus_newOk()); |
| 138 | } |
| 139 | } |
| 140 | |
| 141 | auto err = StringPrintf("UID %d / PID %d does not have any of the following permissions: %s", |
| 142 | uid, pid, Join(permissions, ',').c_str()); |
| 143 | return ::ndk::ScopedAStatus(AStatus_fromExceptionCodeWithMessage(EX_SECURITY, err.c_str())); |
| 144 | } |
| 145 | |
Luke Huang | 7b26b20 | 2019-03-28 14:09:24 +0800 | [diff] [blame] | 146 | namespace { |
| 147 | |
| 148 | // Parse a base64 encoded string into a vector of bytes. |
| 149 | // On failure, return an empty vector. |
| 150 | static std::vector<uint8_t> parseBase64(const std::string& input) { |
| 151 | std::vector<uint8_t> decoded; |
| 152 | size_t out_len; |
| 153 | if (EVP_DecodedLength(&out_len, input.size()) != 1) { |
| 154 | return decoded; |
| 155 | } |
| 156 | // out_len is now an upper bound on the output length. |
| 157 | decoded.resize(out_len); |
| 158 | if (EVP_DecodeBase64(decoded.data(), &out_len, decoded.size(), |
| 159 | reinterpret_cast<const uint8_t*>(input.data()), input.size()) == 1) { |
| 160 | // Possibly shrink the vector if the actual output was smaller than the bound. |
| 161 | decoded.resize(out_len); |
| 162 | } else { |
| 163 | decoded.clear(); |
| 164 | } |
| 165 | if (out_len != SHA256_SIZE) { |
| 166 | decoded.clear(); |
| 167 | } |
| 168 | return decoded; |
| 169 | } |
| 170 | |
| 171 | } // namespace |
| 172 | |
| 173 | ::ndk::ScopedAStatus DnsResolverService::setResolverConfiguration( |
| 174 | int32_t netId, const std::vector<std::string>& servers, |
| 175 | const std::vector<std::string>& domains, const std::vector<int32_t>& params, |
| 176 | const std::string& tlsName, const std::vector<std::string>& tlsServers, |
| 177 | const std::vector<std::string>& tlsFingerprints) { |
| 178 | // Locking happens in PrivateDnsConfiguration and res_* functions. |
| 179 | ENFORCE_INTERNAL_PERMISSIONS(); |
| 180 | |
| 181 | std::set<std::vector<uint8_t>> decoded_fingerprints; |
| 182 | for (const std::string& fingerprint : tlsFingerprints) { |
| 183 | std::vector<uint8_t> decoded = parseBase64(fingerprint); |
| 184 | if (decoded.empty()) { |
| 185 | return ::ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 186 | EINVAL, "ResolverController error: bad fingerprint")); |
| 187 | } |
| 188 | decoded_fingerprints.emplace(decoded); |
| 189 | } |
| 190 | |
| 191 | int err = gDnsResolv->resolverCtrl.setResolverConfiguration( |
| 192 | netId, servers, domains, params, tlsName, tlsServers, decoded_fingerprints); |
| 193 | if (err != 0) { |
| 194 | return ::ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 195 | -err, StringPrintf("ResolverController error: %s", strerror(-err)).c_str())); |
| 196 | } |
| 197 | return ::ndk::ScopedAStatus(AStatus_newOk()); |
| 198 | } |
| 199 | |
| 200 | ::ndk::ScopedAStatus DnsResolverService::getResolverInfo( |
| 201 | int32_t netId, std::vector<std::string>* servers, std::vector<std::string>* domains, |
| 202 | std::vector<std::string>* tlsServers, std::vector<int32_t>* params, |
| 203 | std::vector<int32_t>* stats, std::vector<int32_t>* wait_for_pending_req_timeout_count) { |
| 204 | // Locking happens in PrivateDnsConfiguration and res_* functions. |
| 205 | ENFORCE_NETWORK_STACK_PERMISSIONS(); |
| 206 | |
| 207 | int err = gDnsResolv->resolverCtrl.getResolverInfo(netId, servers, domains, tlsServers, params, |
| 208 | stats, wait_for_pending_req_timeout_count); |
| 209 | if (err != 0) { |
| 210 | return ::ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 211 | -err, StringPrintf("ResolverController error: %s", strerror(-err)).c_str())); |
| 212 | } |
| 213 | return ::ndk::ScopedAStatus(AStatus_newOk()); |
| 214 | } |
| 215 | |
| 216 | ::ndk::ScopedAStatus DnsResolverService::startPrefix64Discovery(int32_t netId) { |
| 217 | // Locking happens in Dns64Configuration. |
| 218 | ENFORCE_NETWORK_STACK_PERMISSIONS(); |
| 219 | gDnsResolv->resolverCtrl.startPrefix64Discovery(netId); |
| 220 | |
| 221 | return ::ndk::ScopedAStatus(AStatus_newOk()); |
| 222 | } |
| 223 | |
| 224 | ::ndk::ScopedAStatus DnsResolverService::stopPrefix64Discovery(int32_t netId) { |
| 225 | // Locking happens in Dns64Configuration. |
| 226 | ENFORCE_NETWORK_STACK_PERMISSIONS(); |
| 227 | gDnsResolv->resolverCtrl.stopPrefix64Discovery(netId); |
| 228 | |
| 229 | return ::ndk::ScopedAStatus(AStatus_newOk()); |
| 230 | } |
| 231 | |
| 232 | ::ndk::ScopedAStatus DnsResolverService::getPrefix64(int netId, std::string* stringPrefix) { |
| 233 | ENFORCE_NETWORK_STACK_PERMISSIONS(); |
| 234 | netdutils::IPPrefix prefix{}; |
| 235 | int err = gDnsResolv->resolverCtrl.getPrefix64(netId, &prefix); |
| 236 | if (err != 0) { |
| 237 | return ::ndk::ScopedAStatus(AStatus_fromServiceSpecificErrorWithMessage( |
| 238 | -err, StringPrintf("ResolverController error: %s", strerror(-err)).c_str())); |
| 239 | } |
| 240 | *stringPrefix = prefix.toString(); |
| 241 | |
| 242 | return ::ndk::ScopedAStatus(AStatus_newOk()); |
| 243 | } |
| 244 | |
Luke Huang | 5bd827c | 2019-03-14 16:10:04 +0800 | [diff] [blame^] | 245 | ::ndk::ScopedAStatus DnsResolverService::clearResolverConfiguration(int netId) { |
| 246 | ENFORCE_NETWORK_STACK_PERMISSIONS(); |
| 247 | |
| 248 | gDnsResolv->resolverCtrl.clearDnsServers(netId); |
| 249 | return ::ndk::ScopedAStatus(AStatus_newOk()); |
| 250 | } |
| 251 | |
Luke Huang | 403c044 | 2019-02-25 15:33:42 +0800 | [diff] [blame] | 252 | } // namespace net |
| 253 | } // namespace android |