lib/policydb.cpp

   1 /*
   2  * Copyright (c) 2011 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 #include "cs.h"
  24 #include "policydb.h"
  25 #include "policyengine.h"
  26 #include <Security/CodeSigning.h>
  27 #include <security_utilities/cfutilities.h>
  28 #include <security_utilities/cfmunge.h>
  29
  30 namespace Security {
  31 namespace CodeSigning {
  32
  33
  34 using namespace SQLite;
  35
  36
  37 //
  38 // The one and only PolicyDatabase object.
  39 // It auto-adapts to readonly vs. writable use.
  40 //
  41 ModuleNexus<PolicyDatabase> PolicyDatabase;
  42
  43
  44 //
  45 // Determine the database path
  46 //
  47 static const char *dbPath()
  48 {
  49         if (const char *s = getenv("SYSPOLICYDATABASE"))
  50                 return s;
  51         return defaultDatabase;
  52 }
  53
  54
  55 //
  56 // Open the database (creating it if necessary and possible).
  57 // Note that this isn't creating the schema; we do that on first write.
  58 //
  59 PolicyDatabase::PolicyDatabase(const char *path, int flags)
  60         : SQLite::Database(path ? path : dbPath(), flags)
  61 {
  62 }
  63
  64 PolicyDatabase::~PolicyDatabase()
  65 { /* virtual */ }
  66
  67
  68 //
  69 // Quick-check the cache for a match.
  70 // Return true on a cache hit, false on failure to confirm a hit for any reason.
  71 //
  72 bool PolicyDatabase::checkCache(CFURLRef path, AuthorityType type, CFMutableDictionaryRef result)
  73 {
  74         // we currently don't use the cache for anything but execution rules
  75         if (type != kAuthorityExecute)
  76                 return false;
  77
  78         SecCSFlags validationFlags = kSecCSDefaultFlags;
  79         if (overrideAssessment())       // we'll force the verdict to 'pass' at the end, so don't sweat validating code
  80                 validationFlags = kSecCSBasicValidateOnly;
  81
  82         CFRef<SecStaticCodeRef> code;
  83         MacOSError::check(SecStaticCodeCreateWithPath(path, kSecCSDefaultFlags, &code.aref()));
  84         if (SecStaticCodeCheckValidity(code, validationFlags, NULL) != noErr)
  85                 return false;   // quick pass - any error is a cache miss
  86         CFRef<CFDictionaryRef> info;
  87         MacOSError::check(SecCodeCopySigningInformation(code, kSecCSDefaultFlags, &info.aref()));
  88         CFDataRef cdHash = CFDataRef(CFDictionaryGetValue(info, kSecCodeInfoUnique));
  89
  90         // check the cache table for a fast match
  91         SQLite::Statement cached(*this, "SELECT allow, expires, label, authority FROM object WHERE type = ?1 and hash = ?2;");
  92         cached.bind(1).integer(type);
  93         cached.bind(2) = cdHash;
  94         if (cached.nextRow()) {
  95                 bool allow = int(cached[0]);
  96                 const char *label = cached[2];
  97                 SQLite::int64 auth = cached[3];
  98                 bool valid = true;
  99                 if (SQLite3::int64 expires = cached[1])
 100                         valid = time(NULL) <= expires;
 101                 if (valid) {
 102                         SYSPOLICY_ASSESS_CACHE_HIT();
 103                         cfadd(result, "{%O=%B}", kSecAssessmentAssessmentVerdict, allow);
 104                         PolicyEngine::addAuthority(result, label, auth, kCFBooleanTrue);
 105                         return true;
 106                 }
 107         }
 108         return false;
 109 }
 110
 111
 112 //
 113 // Purge the object cache of all expired entries
 114 //
 115 void PolicyDatabase::purge(const char *table)
 116 {
 117         SQLite::Statement cleaner(*this,
 118                 "DELETE FROM ?1 WHERE expires < DATE_TIME('now');");
 119         cleaner.bind(1) = table;
 120         cleaner.execute();
 121 }
 122
 123
 124 //
 125 // Check the override-enable master flag
 126 //
 127 bool overrideAssessment()
 128 {
 129         if (::access(visibleSecurityFlagFile, F_OK) == 0) {
 130                 return false;
 131         } else if (errno == ENOENT) {
 132                 return true;
 133         } else
 134                 UnixError::throwMe();
 135 }
 136
 137
 138 } // end namespace CodeSigning
 139 } // end namespace Security