securityd/src/AuthorizationEngine.cpp

   1 /*
   2  * Copyright (c) 2000-2004,2006-2012 Apple Inc. All Rights Reserved.
   3  *
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   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
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  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #include "AuthorizationEngine.h"
  25 #include <security_cdsa_utilities/AuthorizationWalkers.h>
  26 #include <Security/AuthorizationPriv.h>
  27 #include <Security/AuthorizationDB.h>
  28
  29 #include "authority.h"
  30
  31 #include <Security/AuthorizationTags.h>
  32 #include <Security/AuthorizationTagsPriv.h>
  33 #include <security_utilities/logging.h>
  34 #include <security_utilities/cfutilities.h>
  35 #include <security_utilities/debugging.h>
  36 #include "server.h"
  37
  38 #include <CoreFoundation/CFData.h>
  39 #include <CoreFoundation/CFNumber.h>
  40 #include <CoreFoundation/CFPropertyList.h>
  41
  42 #include <errno.h>
  43 #include <fcntl.h>
  44 #include <float.h>
  45 #include <sandbox.h>
  46
  47 #include <bsm/audit_uevents.h>      // AUE_ssauth*
  48 #include "ccaudit_extensions.h"
  49
  50 namespace Authorization {
  51
  52 using namespace CommonCriteria::Securityd;
  53
  54
  55 //
  56 // Errors to be thrown
  57 //
  58 Error::Error(int err) : error(err)
  59 {
  60 }
  61
  62 const char *Error::what() const throw()
  63 { return "Authorization error"; }
  64
  65 int Error::unixError() const throw()
  66 { return error; }       // @@@ eventually...
  67
  68 OSStatus Error::osStatus() const throw()
  69 { return error; }
  70
  71 void Error::throwMe(int err) { throw Error(err); }
  72
  73 //
  74 // Engine class
  75 //
  76 Engine::Engine(const char *configFile) : mAuthdb(configFile)
  77 {
  78 }
  79
  80 Engine::~Engine()
  81 {
  82 }
  83
  84
  85 /*!
  86         @function AuthorizationEngine::authorize
  87
  88         @@@.
  89
  90         @param inRights (input) List of rights being requested for authorization.
  91         @param environment (optional/input) Environment containing information to be used during evaluation.
  92         @param flags (input) Optional flags @@@ see AuthorizationCreate for a description.
  93         @param inCredentials (input) Credentials already held by the caller.
  94         @param outCredentials (output/optional) Credentials obtained, used or refreshed during this call to authorize the requested rights.
  95         @param outRights (output/optional) Subset of inRights which were actually authorized.
  96
  97         @results Returns errAuthorizationSuccess if all rights requested are authorized, or if the kAuthorizationFlagPartialRights flag was specified.  Might return other status values like errAuthorizationDenied, errAuthorizationCanceled or errAuthorizationInteractionNotAllowed
  98 */
  99 OSStatus
 100 Engine::authorize(const AuthItemSet &inRights, const AuthItemSet &environment,
 101         AuthorizationFlags flags, const CredentialSet *inCredentials, CredentialSet *outCredentials,
 102         AuthItemSet &outRights, AuthorizationToken &auth)
 103 {
 104         CredentialSet credentials;
 105         OSStatus status = errAuthorizationSuccess;
 106     SecurityAgent::Reason reason = SecurityAgent::noReason;
 107
 108         // Get current time of day.
 109         CFAbsoluteTime now = CFAbsoluteTimeGetCurrent();
 110
 111         // Update rules from database if needed
 112         mAuthdb.sync(now);
 113
 114         // Check if a credential was passed into the environment and we were asked to extend the rights
 115         if (flags & kAuthorizationFlagExtendRights)
 116         {
 117                 string username, password;
 118                 bool shared = false;
 119                 for (AuthItemSet::iterator item = environment.begin(); item != environment.end(); item ++)
 120                 {
 121                         if (!strcmp((*item)->name(), kAuthorizationEnvironmentUsername))
 122                                 username = (*item)->stringValue();
 123                         else if (!strcmp((*item)->name(), kAuthorizationEnvironmentPassword))
 124                                 password = (*item)->stringValue();
 125                         else if (!strcmp((*item)->name(), kAuthorizationEnvironmentShared))
 126                                 shared = true;
 127                 }
 128
 129                 if (username.length())
 130                 {
 131                         // Let's create a credential from the passed in username and password.
 132                         Credential newCredential(username, password, shared);
 133                         // If it's valid insert it into the credentials list.  Normally this is
 134                         // only done if it actually authorizes a requested right, but for this
 135                         // special case (environment) we do it even when no rights are being requested.
 136                         if (newCredential->isValid())
 137                                 credentials.insert(newCredential);
 138                 }
 139         }
 140
 141         // generate hints for every authorization
 142     AuthItemSet environmentToClient = environment;
 143
 144     RightAuthenticationLogger logger(auth.creatorAuditToken(), AUE_ssauthorize);
 145
 146         // create a vector with the first right first
 147         std::vector<AuthItemRef>                tempRights;
 148         for (AuthItemSet::const_iterator it = inRights.begin(); it != inRights.end(); ++it) {
 149                 if (inRights.firstItemName != NULL && strcmp((*it)->name(), inRights.firstItemName) == 0)
 150                         tempRights.insert(tempRights.begin(), *it);
 151                 else
 152                         tempRights.push_back(*it);
 153         }
 154
 155         bool authExtractPassword = false;
 156         std::vector<AuthItemRef>::const_iterator end = tempRights.end();
 157         for (std::vector<AuthItemRef>::const_iterator it = tempRights.begin(); it != end; ++it)
 158         {
 159                 // Get the rule for each right we are trying to obtain.
 160                 const Rule &toplevelRule = mAuthdb.getRule(*it);
 161
 162                 if (false == authExtractPassword)
 163                         authExtractPassword = toplevelRule->extractPassword();
 164
 165         string processName = "unknown";
 166         string authCreatorName = "unknown";
 167                 {
 168                         StLock<Mutex> _(Server::process());
 169                 if (SecCodeRef code = Server::process().currentGuest()) {
 170                     CFRef<CFURLRef> path;
 171                 if (!SecCodeCopyPath(code, kSecCSDefaultFlags, &path.aref()))
 172                         processName = cfString(path);
 173                         }
 174         }
 175                 authCreatorName = auth.creatorPath();
 176
 177         if (sandbox_check(Server::process().pid(), "authorization-right-obtain", SANDBOX_FILTER_RIGHT_NAME, (*it)->name())) {
 178             Syslog::error("Sandbox denied authorizing right '%s' by client '%s' [%d]", (*it)->name(), processName.c_str(), Server::process().pid());
 179             return errAuthorizationDenied;
 180         }
 181         if (auth.creatorSandboxed() && sandbox_check(auth.creatorPid(), "authorization-right-obtain", SANDBOX_FILTER_RIGHT_NAME, (*it)->name())) {
 182             Syslog::error("Sandbox denied authorizing right '%s' for authorization created by '%s' [%d]", (*it)->name(), authCreatorName.c_str(), auth.creatorPid());
 183             return errAuthorizationDenied;
 184         }
 185
 186                 OSStatus result = toplevelRule->evaluate(*it, toplevelRule, environmentToClient, flags, now, inCredentials, credentials, auth, reason, authExtractPassword);
 187                 secdebug("autheval", "evaluate rule %s for right %s returned %d.", toplevelRule->name().c_str(), (*it)->name(), int(result));
 188         SECURITYD_AUTH_EVALRIGHT(&auth, (char *)(*it)->name(), result);
 189
 190         logger.setRight((*it)->name());
 191         logger.logAuthorizationResult(processName.c_str(), authCreatorName.c_str(), result);
 192
 193         if (result == errAuthorizationSuccess)
 194         {
 195             outRights.insert(*it);
 196             Syslog::info("Succeeded authorizing right '%s' by client '%s' [%d] for authorization created by '%s' [%d] (%X,%d)", (*it)->name(), processName.c_str(), Server::process().pid(), authCreatorName.c_str(), auth.creatorPid(), uint32_t(flags), auth.operatesAsLeastPrivileged());
 197         }
 198         else if (result == errAuthorizationDenied || result == errAuthorizationInteractionNotAllowed)
 199         {
 200             if (result == errAuthorizationDenied)
 201             {
 202                  secdebug("autheval", "Failed to authorize right '%s' by client '%s' [%d] for authorization created by '%s' [%d] (%X,%d)", (*it)->name(), processName.c_str(), Server::process().pid(), authCreatorName.c_str(), auth.creatorPid(), uint32_t(flags), auth.operatesAsLeastPrivileged());
 203             }
 204
 205             // add creator pid to authorization token
 206             if (!(flags & kAuthorizationFlagPartialRights))
 207             {
 208                 status = result;
 209                 break;
 210             }
 211         }
 212         else if (result == errAuthorizationCanceled)
 213         {
 214             status = result;
 215             break;
 216         }
 217         else
 218         {
 219             Syslog::error("Engine::authorize: Rule::evaluate returned %ld returning errAuthorizationInternal", result);
 220             status = errAuthorizationInternal;
 221             break;
 222                 }
 223         }
 224
 225     // purge all uid credentials from the outCredentials for least privileged mode
 226     if (auth.operatesAsLeastPrivileged()) {
 227         CredentialSet::const_iterator current, it = outCredentials->begin();
 228         while(it != outCredentials->end()) {
 229             current = it++;
 230             if (!(*current)->isRight()) {
 231                 outCredentials->erase(current);
 232             }
 233         }
 234     }
 235
 236         if (outCredentials)
 237                 outCredentials->swap(credentials);
 238
 239         return status;
 240 }
 241
 242 OSStatus
 243 Engine::verifyModification(string inRightName, bool remove,
 244         const CredentialSet *inCredentials, CredentialSet *outCredentials, AuthorizationToken &auth)
 245 {
 246         // Validate right
 247
 248         // meta rights are constructed as follows:
 249         // we don't allow setting of wildcard rights, so you can only be more specific
 250         // note that you should never restrict things with a wildcard right without disallowing
 251         // changes to the entire domain.  ie.
 252         //              system.privilege.               -> never
 253         //              config.add.system.privilege.    -> never
 254         //              config.modify.system.privilege. -> never
 255         //              config.delete.system.privilege. -> never
 256         // For now we don't allow any configuration of configuration rules
 257         //              config.config. -> never
 258
 259         string rightnameToCheck;
 260
 261         // @@@ verify right name is is not NULL or zero length
 262         if (inRightName.length() == 0)
 263                 return errAuthorizationDenied;
 264
 265         // @@@ make sure it isn't a wildcard right by checking trailing "."
 266         if ( *(inRightName.rbegin()) == '.')
 267                 return errAuthorizationDenied;
 268
 269         // @@@ make sure it isn't a configure right by checking it doesn't start with config.
 270         if (inRightName.find(kConfigRight, 0) != string::npos)
 271         {
 272                 // special handling of meta right change:
 273                 // config.add. config.modify. config.remove. config.{}.
 274                 // check for config.<right> (which always starts with config.config.)
 275                 rightnameToCheck = string(kConfigRight) + inRightName;
 276         }
 277         else
 278         {
 279                 // regular check of rights
 280                 bool existingRule = mAuthdb.existRule(inRightName);
 281                 if (!remove)
 282                 {
 283                         if (existingRule)
 284                                 rightnameToCheck = string(kAuthorizationConfigRightModify) + inRightName;
 285                         else
 286                                 rightnameToCheck = string(kAuthorizationConfigRightAdd) + inRightName;
 287                 }
 288                 else
 289                 {
 290                         if (existingRule)
 291                                 rightnameToCheck = string(kAuthorizationConfigRightRemove) + inRightName;
 292                         else
 293                         {
 294                                 secdebug("engine", "rule %s doesn't exist.", inRightName.c_str());
 295                                 return errAuthorizationSuccess; // doesn't exist, done
 296                         }
 297                 }
 298         }
 299
 300
 301         AuthItemSet rights, environment, outRights;
 302         rights.insert(AuthItemRef(rightnameToCheck.c_str()));
 303         secdebug("engine", "authorizing %s for db modification.", rightnameToCheck.c_str());
 304         return authorize(rights, environment, kAuthorizationFlagDefaults | kAuthorizationFlagInteractionAllowed | kAuthorizationFlagExtendRights, inCredentials, outCredentials, outRights, auth);
 305 }
 306
 307 OSStatus
 308 Engine::getRule(string &inRightName, CFDictionaryRef *outRuleDefinition)
 309 {
 310         // Get current time of day.
 311         CFAbsoluteTime now = CFAbsoluteTimeGetCurrent();
 312
 313         // Update rules from database if needed
 314         mAuthdb.sync(now);
 315
 316         CFDictionaryRef definition = mAuthdb.getRuleDefinition(inRightName);
 317         if (definition)
 318         {
 319                 if (outRuleDefinition)
 320                         *outRuleDefinition = definition;
 321                 else
 322                         CFRelease(definition);
 323
 324                 return errAuthorizationSuccess;
 325         }
 326
 327         return errAuthorizationDenied;
 328 }
 329
 330 OSStatus
 331 Engine::setRule(const char *inRightName, CFDictionaryRef inRuleDefinition, const CredentialSet *inCredentials, CredentialSet *outCredentials, AuthorizationToken &auth)
 332 {
 333         // Validate rule by constructing it from the passed dictionary
 334         if (!mAuthdb.validateRule(inRightName, inRuleDefinition))
 335                 return errAuthorizationDenied; // @@@ separate error for this?
 336
 337         OSStatus result = verifyModification(inRightName, false /*setting, not removing*/, inCredentials, outCredentials, auth);
 338         if (result != errAuthorizationSuccess)
 339                 return result;
 340
 341         // set the rule for the right and save the database
 342         mAuthdb.setRule(inRightName, inRuleDefinition);
 343
 344         return errAuthorizationSuccess;
 345 }
 346
 347 OSStatus
 348 Engine::removeRule(const char *inRightName, const CredentialSet *inCredentials, CredentialSet *outCredentials, AuthorizationToken &auth)
 349 {
 350         // Get current time of day.
 351         CFAbsoluteTime now = CFAbsoluteTimeGetCurrent();
 352
 353         // Update rules from database if needed
 354         mAuthdb.sync(now);
 355
 356         OSStatus result = verifyModification(inRightName, true /*removing*/, inCredentials, outCredentials, auth);
 357         if (result != errAuthorizationSuccess)
 358                 return result;
 359
 360         // set the rule for the right and save the database
 361         mAuthdb.removeRule(inRightName);
 362
 363         return errAuthorizationSuccess;
 364 }
 365
 366 }       // end namespace Authorization