securityd/src/notifications.cpp

   1 /*
   2  * Copyright (c) 2000-2004,2006,2008 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24
  25 //
  26 // notifications - handling of securityd-gated notification messages
  27 //
  28 #include <notify.h>
  29 #include <sys/sysctl.h>
  30
  31 #include "notifications.h"
  32 #include "server.h"
  33 #include "connection.h"
  34 #include "dictionary.h"
  35 #include "SharedMemoryClient.h"
  36
  37 #include <securityd_client/ucspNotify.h>
  38 #include <security_utilities/casts.h>
  39
  40 #include <Security/SecKeychain.h>
  41 #include <Security/SecItemInternal.h>
  42
  43 Listener::ListenerMap& Listener::listeners = *(new Listener::ListenerMap);
  44 Mutex Listener::setLock(Mutex::recursive);
  45
  46
  47 //
  48 // Listener basics
  49 //
  50 Listener::Listener(NotificationDomain dom, NotificationMask evs, mach_port_t port)
  51         : domain(dom), events(evs)
  52 {
  53         assert(events);         // what's the point?
  54
  55     // register in listener set
  56     StLock<Mutex> _(setLock);
  57     listeners.insert(ListenerMap::value_type(port, this));
  58
  59         secinfo("notify", "%p created for domain 0x%x events 0x%x port %d",
  60                 this, dom, evs, port);
  61 }
  62
  63 Listener::~Listener()
  64 {
  65     secinfo("notify", "%p destroyed", this);
  66 }
  67
  68
  69 //
  70 // Send a notification to all registered listeners
  71 //
  72 void Listener::notify(NotificationDomain domain,
  73         NotificationEvent event, const CssmData &data)
  74 {
  75         RefPointer<Notification> message = new Notification(domain, event, 0, data);
  76         StLock<Mutex> _(setLock);
  77         sendNotification(message);
  78 }
  79
  80 void Listener::notify(NotificationDomain domain,
  81         NotificationEvent event, uint32 sequence, const CssmData &data, audit_token_t auditToken)
  82 {
  83         Connection &current = Server::active().connection();
  84         RefPointer<Notification> message = new Notification(domain, event, sequence, data);
  85         if (current.inSequence(message)) {
  86                 StLock<Mutex> _(setLock);
  87
  88                 // This is a total layer violation, but no better place to put it
  89                 uid_t uid = audit_token_to_euid(auditToken);
  90                 gid_t gid = audit_token_to_egid(auditToken);
  91                 SharedMemoryListener::createDefaultSharedMemoryListener(uid, gid);
  92
  93                 sendNotification(message);
  94                 while (RefPointer<Notification> next = current.popNotification())
  95                         sendNotification(next);
  96         }
  97 }
  98
  99 void Listener::sendNotification(Notification *message)
 100 {
 101     secdebug("MDSPRIVACY","Listener::sendNotification for uid/euid: %d/%d", getuid(), geteuid());
 102
 103     for (ListenerMap::const_iterator it = listeners.begin();
 104             it != listeners.end(); it++) {
 105                 Listener *listener = it->second;
 106                 if (listener->domain == kNotificationDomainAll ||
 107             (message->domain == listener->domain && listener->wants(message->event)))
 108                         listener->notifyMe(message);
 109         }
 110 }
 111
 112
 113 //
 114 // Handle a port death or deallocation by removing all Listeners using that port.
 115 // Returns true iff we had one.
 116 //
 117 bool Listener::remove(Port port)
 118 {
 119     typedef ListenerMap::iterator Iterator;
 120     StLock<Mutex> _(setLock);
 121     pair<Iterator, Iterator> range = listeners.equal_range(port);
 122     if (range.first == range.second)
 123         return false;   // not one of ours
 124
 125         assert(range.first != listeners.end());
 126         secinfo("notify", "remove port %d", port.port());
 127 #if !defined(NDEBUG)
 128     for (Iterator it = range.first; it != range.second; it++) {
 129                 assert(it->first == port);
 130                 secinfo("notify", "%p listener removed", it->second.get());
 131         }
 132 #endif //NDEBUG
 133     listeners.erase(range.first, range.second);
 134         port.destroy();
 135     return true;        // got it
 136 }
 137
 138
 139 //
 140 // Notification message objects
 141 //
 142 Listener::Notification::Notification(NotificationDomain inDomain,
 143         NotificationEvent inEvent, uint32 seq, const CssmData &inData)
 144         : domain(inDomain), event(inEvent), sequence(seq), data(Allocator::standard(), inData)
 145 {
 146         secinfo("notify", "%p notification created domain 0x%x event %d seq %d",
 147                 this, domain, event, sequence);
 148 }
 149
 150 Listener::Notification::~Notification()
 151 {
 152         secinfo("notify", "%p notification done domain 0x%x event %d seq %d",
 153                 this, domain, event, sequence);
 154 }
 155
 156 std::string Listener::Notification::description() const {
 157     return SharedMemoryCommon::notificationDescription(domain, event) +
 158         ", Seq: " + std::to_string(sequence) + ", Data: " + std::to_string(this->size());
 159 }
 160
 161 //
 162 // Jitter buffering
 163 //
 164 bool Listener::JitterBuffer::inSequence(Notification *message)
 165 {
 166         if (message->sequence == mNotifyLast + 1) {     // next in sequence
 167                 mNotifyLast++;                  // record next sequence
 168                 return true;                    // go ahead
 169         } else {
 170                 secinfo("notify-jit", "%p out of sequence (last %d got %d); buffering",
 171                         message, mNotifyLast, message->sequence);
 172                 mBuffer[message->sequence] = message;   // save for later
 173                 return false;                   // hold your fire
 174         }
 175 }
 176
 177 RefPointer<Listener::Notification> Listener::JitterBuffer::popNotification()
 178 {
 179         JBuffer::iterator it = mBuffer.find(mNotifyLast + 1);   // have next message?
 180         if (it == mBuffer.end())
 181                 return NULL;                    // nothing here
 182         else {
 183                 RefPointer<Notification> result = it->second;   // save value
 184                 mBuffer.erase(it);              // remove from buffer
 185                 secinfo("notify-jit", "%p retrieved from jitter buffer", result.get());
 186                 return result;                  // return it
 187         }
 188 }
 189
 190 bool Listener::testPredicate(const std::function<bool(const Listener& listener)> test) {
 191     StLock<Mutex> _(setLock);
 192     for (ListenerMap::const_iterator it = listeners.begin(); it != listeners.end(); it++) {
 193         if (test(*(it->second)))
 194             return true;
 195     }
 196     return false;
 197 }
 198
 199 /*
 200  * Shared memory listener
 201  */
 202
 203
 204 SharedMemoryListener::SharedMemoryListener(const char* segmentName, SegmentOffsetType segmentSize, uid_t uid, gid_t gid) :
 205         Listener (kNotificationDomainAll, kNotificationAllEvents),
 206         SharedMemoryServer (segmentName, segmentSize, uid, gid),
 207         mActive (false)
 208 {
 209 }
 210
 211 SharedMemoryListener::~SharedMemoryListener ()
 212 {
 213 }
 214
 215 // Look for a listener for a given user ID
 216 bool SharedMemoryListener::findUID(uid_t uid) {
 217     return Listener::testPredicate([uid](const Listener& listener) -> bool {
 218         try {
 219             // There may be elements in the map that are not SharedMemoryListeners
 220             const SharedMemoryListener& smlListener = dynamic_cast<const SharedMemoryListener&>(listener);
 221             if (smlListener.mUID == uid)
 222                 return true;
 223         }
 224         catch (...) {
 225             return false;
 226         }
 227         return false;
 228     }
 229     );
 230     return false;
 231 }
 232
 233 void SharedMemoryListener::createDefaultSharedMemoryListener(uid_t uid, gid_t gid) {
 234     uid_t fuid = SharedMemoryCommon::fixUID(uid);
 235     if (fuid != 0) { // already created when securityd started up
 236         if (!SharedMemoryListener::findUID(fuid)) {
 237             secdebug("MDSPRIVACY","creating SharedMemoryListener for uid/gid: %d/%d", fuid, gid);
 238             // A side effect of creation of a SharedMemoryListener is addition to the ListenerMap
 239 #ifndef __clang_analyzer__
 240             /* __unused auto sml = */ new SharedMemoryListener(SharedMemoryCommon::kDefaultSecurityMessagesName, kSharedMemoryPoolSize, uid, gid);
 241 #endif  // __clang_analyzer__
 242         }
 243     }
 244 }
 245
 246 // Simpler local version of PrimaryKeyImpl::getUInt32
 247 uint32 SharedMemoryListener::getRecordType(const CssmData& val) const {
 248     if (val.Length < sizeof(uint32))
 249         return 0;               // Not really but good enough for here
 250
 251     const uint8 *pv = val.Data;
 252     // @@@ Assumes data written in big endian.
 253     uint32 value = (pv[0] << 24) + (pv[1] << 16) + (pv[2] << 8) + pv[3];
 254     return value;
 255 }
 256
 257 bool SharedMemoryListener::isTrustEvent(Notification *notification) {
 258     bool trustEvent = false;
 259
 260     switch (notification->event) {
 261         case kSecDefaultChangedEvent:
 262         case kSecKeychainListChangedEvent:
 263         case kSecTrustSettingsChangedEvent:
 264             trustEvent = true;
 265             break;
 266         case kSecAddEvent:
 267         case kSecDeleteEvent:
 268         case kSecUpdateEvent:
 269             {
 270                 NameValueDictionary dictionary (notification->data);
 271                 const NameValuePair *item = dictionary.FindByName(ITEM_KEY);
 272                 if (item && (CSSM_DB_RECORDTYPE)getRecordType(item->Value()) == CSSM_DL_DB_RECORD_X509_CERTIFICATE) {
 273                     trustEvent = true;
 274                 }
 275             }
 276             break;
 277         default:
 278             break;
 279     }
 280
 281     if (trustEvent) {
 282         uint32_t result = notify_post(kSecServerCertificateTrustNotification);
 283         if (result != NOTIFY_STATUS_OK) {
 284             secdebug("MDSPRIVACY","Certificate trust event notification failed: %d", result);
 285         }
 286     }
 287
 288     secdebug("MDSPRIVACY","[%03d] Event is %s trust event", mUID, trustEvent?"a":"not a");
 289     return trustEvent;
 290 }
 291
 292 bool SharedMemoryListener::needsPrivacyFilter(Notification *notification) {
 293     if (notification->domain == kNotificationDomainPCSC || notification->domain == kNotificationDomainCDSA)
 294         return false;
 295
 296     // kNotificationDomainDatabase              = 1, // something happened to a database (aka keychain)
 297     switch (notification->event) {
 298     case kSecLockEvent:             // kNotificationEventLocked
 299     case kSecUnlockEvent:           // kNotificationEventUnlocked
 300     case kSecPasswordChangedEvent:  // kNotificationEventPassphraseChanged
 301     case kSecDefaultChangedEvent:
 302     case kSecDataAccessEvent:
 303     case kSecKeychainListChangedEvent:
 304     case kSecTrustSettingsChangedEvent:
 305         return false;
 306     case kSecAddEvent:
 307     case kSecDeleteEvent:
 308     case kSecUpdateEvent:
 309         break;
 310     }
 311
 312     secdebug("MDSPRIVACY","[%03d] Evaluating event %s", mUID, notification->description().c_str());
 313
 314     NameValueDictionary dictionary (notification->data);
 315     const NameValuePair *item = dictionary.FindByName(ITEM_KEY);
 316
 317     // If we don't have an item, there is nothing to filter
 318     if (!item) {
 319         secdebug("MDSPRIVACY","[%03d] Item event did not contain an item", mUID);
 320         return false;
 321     }
 322
 323     pid_t thisPid = 0;
 324     const NameValuePair *pidRef = dictionary.FindByName(PID_KEY);
 325     if (pidRef != 0) {
 326         thisPid = n2h(*reinterpret_cast<pid_t*>(pidRef->Value().data()));
 327     }
 328
 329     uid_t out_euid = 0;
 330     int rx = SharedMemoryListener::get_process_euid(thisPid, out_euid);
 331     if (rx != 0) {
 332         secdebug("MDSPRIVACY","[%03d] get_process_euid failed (rx=%d), filtering out item", mUID, rx);
 333         return true;
 334     }
 335
 336     if (out_euid == mUID) {
 337         return false;       // Listener owns this item, so no filtering
 338     }
 339
 340     // Allow processes running as root to pass through certificates
 341     if (out_euid == 0) {
 342         CSSM_DB_RECORDTYPE recordType = getRecordType(item->Value());
 343         if (recordType == CSSM_DL_DB_RECORD_X509_CERTIFICATE) {
 344             return false;
 345         }
 346     }
 347
 348     secdebug("MDSPRIVACY","[%03d] Filtering event %s", mUID, notification->description().c_str());
 349     return true;
 350 }
 351
 352 const double kServerWait = 0.005; // time in seconds before clients will be notified that data is available
 353
 354 void SharedMemoryListener::notifyMe(Notification* notification)
 355 {
 356     const void* data = notification->data.data();
 357     size_t length = notification->data.length();
 358     /* enforce a maximum size of 16k for notifications */
 359     if (length > 16384) return;
 360
 361     isTrustEvent(notification);
 362     if (needsPrivacyFilter(notification)) {
 363         return; // just drop it
 364     }
 365
 366     secdebug("MDSPRIVACY","[%03d] WriteMessage event %s", mUID, notification->description().c_str());
 367
 368     WriteMessage (notification->domain, notification->event, data, int_cast<size_t, UInt32>(length));
 369
 370     if (!mActive)
 371     {
 372         Server::active().setTimer (this, Time::Interval(kServerWait));
 373         mActive = true;
 374     }
 375 }
 376
 377 void SharedMemoryListener::action ()
 378 {
 379         secinfo("notify", "Posted notification to clients.");
 380     secdebug("MDSPRIVACY","[%03d] Posted notification to clients", mUID);
 381         notify_post (mSegmentName.c_str ());
 382         mActive = false;
 383 }
 384
 385 int SharedMemoryListener::get_process_euid(pid_t pid, uid_t& out_euid) {
 386     struct kinfo_proc proc_info = {};
 387     int mib[] = {CTL_KERN, KERN_PROC, KERN_PROC_PID, pid};
 388     size_t len = sizeof(struct kinfo_proc);
 389     int ret = sysctl(mib, (sizeof(mib)/sizeof(int)), &proc_info, &len, NULL, 0);
 390
 391     out_euid = -1;
 392     if (ret == 0) {
 393         out_euid = proc_info.kp_eproc.e_ucred.cr_uid;
 394     }
 395     return ret;
 396 }