src/acl_keychain.cpp

   1 /*
   2  * Copyright (c) 2000-2004,2007-2008 Apple Inc. All Rights Reserved.
   3  *
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   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
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   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,
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  23
  24
  25 //
  26 // acl_keychain - a subject type for the protected-path
  27 //                                keychain prompt interaction model.
  28 //
  29 // Arguments in CSSM_LIST form:
  30 //      list[1] = CssmData: CSSM_ACL_KEYCHAIN_PROMPT_SELECTOR structure
  31 //      list[2] = CssmData: Descriptive String (presented to user in protected dialogs)
  32 // For legacy compatibility, we accept a single-entry form
  33 //      list[1] = CssmData: Descriptive String
  34 // which defaults to a particular CSSM_ACL_KEYCHAIN_PROMPT_SELECTOR structure value.
  35 // This is never produced by current code, and is considered purely a legacy feature.
  36 //
  37 // On-disk (flattened) representation:
  38 // In order to accommodate legacy formats nicely, we use the binary-versioning feature
  39 // of the ACL machinery. Version 0 is the legacy format (storing only the description
  40 // string), while Version 1 contains both selector and description. We are now always
  41 // writing version-1 data, but will continue to recognize version-0 data indefinitely
  42 // for really, really old keychain items.
  43 //
  44 #include "acl_keychain.h"
  45 #include "agentquery.h"
  46 #include "acls.h"
  47 #include "connection.h"
  48 #include "database.h"
  49 #include "server.h"
  50 #include <security_utilities/debugging.h>
  51 #include <security_utilities/logging.h>
  52 #include <security_cdsa_utilities/osxverifier.h>
  53 #include <algorithm>
  54
  55
  56 #define ACCEPT_LEGACY_FORM 1
  57
  58
  59 //
  60 // The default for the selector structure.
  61 //
  62 CSSM_ACL_KEYCHAIN_PROMPT_SELECTOR KeychainPromptAclSubject::defaultSelector = {
  63         CSSM_ACL_KEYCHAIN_PROMPT_CURRENT_VERSION,       // version
  64         0                                                                                       // flags
  65 };
  66
  67
  68 //
  69 // Validate a credential set against this subject.
  70 //
  71 bool KeychainPromptAclSubject::validate(const AclValidationContext &context,
  72     const TypedList &sample) const
  73 {
  74     if (SecurityServerEnvironment *env = context.environment<SecurityServerEnvironment>()) {
  75                 Process &process = Server::process();
  76                 secdebug("kcacl", "Keychain query for process %d (UID %d)", process.pid(), process.uid());
  77
  78                 // assemble the effective validity mode mask
  79                 uint32_t mode = Maker::defaultMode;
  80                 const uint16_t &flags = selector.flags;
  81                 if (flags & CSSM_ACL_KEYCHAIN_PROMPT_UNSIGNED_ACT)
  82                         mode = (mode & ~CSSM_ACL_KEYCHAIN_PROMPT_UNSIGNED) | (flags & CSSM_ACL_KEYCHAIN_PROMPT_UNSIGNED);
  83                 if (flags & CSSM_ACL_KEYCHAIN_PROMPT_INVALID_ACT)
  84                         mode = (mode & ~CSSM_ACL_KEYCHAIN_PROMPT_INVALID) | (flags & CSSM_ACL_KEYCHAIN_PROMPT_INVALID);
  85
  86                 // determine signed/validity status of client, without reference to any particular Code Requirement
  87                 SecCodeRef clientCode = process.currentGuest();
  88                 Server::active().longTermActivity();
  89                 OSStatus validation = clientCode ? SecCodeCheckValidity(clientCode, kSecCSDefaultFlags, NULL) : errSecCSStaticCodeNotFound;
  90                 switch (validation) {
  91                 case noErr:                                                     // client is signed and valid
  92                         secdebug("kcacl", "client is valid, proceeding");
  93                         break;
  94                 case errSecCSUnsigned:                          // client is not signed
  95                         if (!(mode & CSSM_ACL_KEYCHAIN_PROMPT_UNSIGNED)) {
  96                                 secdebug("kcacl", "client is unsigned, suppressing prompt");
  97                                 return false;
  98                         }
  99                         break;
 100                 case errSecCSSignatureFailed:           // client signed but signature is broken
 101                 case errSecCSGuestInvalid:                      // client signed but dynamically invalid
 102                 case errSecCSStaticCodeNotFound:        // client not on disk (or unreadable)
 103                         if (!(mode & CSSM_ACL_KEYCHAIN_PROMPT_INVALID)) {
 104                                 secdebug("kcacl", "client is invalid, suppressing prompt");
 105                                 Syslog::info("suppressing keychain prompt for invalidly signed client %s(%d)",
 106                                         process.getPath().c_str(), process.pid());
 107                                 return false;
 108                         }
 109                         Syslog::info("attempting keychain prompt for invalidly signed client %s(%d)",
 110                                 process.getPath().c_str(), process.pid());
 111                         break;
 112                 default:                                                        // something else went wrong
 113                         secdebug("kcacl", "client validation failed rc=%d, suppressing prompt", int32_t(validation));
 114                         return false;
 115                 }
 116
 117                 // At this point, we're committed to try to Pop The Question. Now, how?
 118
 119                 // does the user need to type in the passphrase?
 120         const Database *db = env->database;
 121         bool needPassphrase = db && (selector.flags & CSSM_ACL_KEYCHAIN_PROMPT_REQUIRE_PASSPHRASE);
 122
 123                 // an application (i.e. Keychain Access.app :-) can force this option
 124                 if (clientCode && validation == noErr) {
 125                         CFRef<CFDictionaryRef> dict;
 126                         if (SecCodeCopySigningInformation(clientCode, kSecCSDefaultFlags, &dict.aref()) == noErr)
 127                                 if (CFDictionaryRef info = CFDictionaryRef(CFDictionaryGetValue(dict, kSecCodeInfoPList)))
 128                                         needPassphrase |=
 129                                                 (CFDictionaryGetValue(info, CFSTR("SecForcePassphrasePrompt")) != NULL);
 130                 }
 131
 132                 // pop The Question
 133                 if (db && db->belongsToSystem() && !hasAuthorizedForSystemKeychain()) {
 134                         QueryKeychainAuth query;
 135                         query.inferHints(Server::process());
 136                         if (query(db ? db->dbName() : NULL, description.c_str(), context.authorization(), NULL) != SecurityAgent::noReason)
 137                                 return false;
 138                         return true;
 139                 } else {
 140                         QueryKeychainUse query(needPassphrase, db);
 141                         query.inferHints(Server::process());
 142                         query.addHint(AGENT_HINT_CLIENT_VALIDITY, &validation, sizeof(validation));
 143                         if (query.queryUser(db ? db->dbName() : NULL,
 144                                 description.c_str(), context.authorization()) != SecurityAgent::noReason)
 145                                 return false;
 146
 147                         // process an "always allow..." response
 148                         if (query.remember && clientCode) {
 149                                 RefPointer<OSXCode> clientXCode = new OSXCodeWrap(clientCode);
 150                                 RefPointer<AclSubject> subject = new CodeSignatureAclSubject(OSXVerifier(clientXCode));
 151                                 SecurityServerAcl::addToStandardACL(context, subject);
 152                         }
 153
 154                         // finally, return the actual user response
 155                         return query.allow;
 156                 }
 157     }
 158         return false;        // default to deny without prejudice
 159 }
 160
 161
 162 //
 163 // Make a copy of this subject in CSSM_LIST form
 164 //
 165 CssmList KeychainPromptAclSubject::toList(Allocator &alloc) const
 166 {
 167         // always issue new (non-legacy) form
 168         return TypedList(alloc, CSSM_ACL_SUBJECT_TYPE_KEYCHAIN_PROMPT,
 169                 new(alloc) ListElement(alloc, CssmData::wrap(selector)),
 170         new(alloc) ListElement(alloc, description));
 171 }
 172
 173 //
 174 // Has the caller recently authorized in such a way as to render unnecessary
 175 // the usual QueryKeychainAuth dialog?  (The right is specific to Keychain
 176 // Access' way of editing a system keychain.)
 177 //
 178 bool KeychainPromptAclSubject::hasAuthorizedForSystemKeychain() const
 179 {
 180     string rightString = "system.keychain.modify";
 181     return Server::session().isRightAuthorized(rightString, Server::connection(), false/*no UI*/);
 182 }
 183
 184
 185
 186 //
 187 // Create a KeychainPromptAclSubject
 188 //
 189 uint32_t KeychainPromptAclSubject::Maker::defaultMode;
 190
 191 KeychainPromptAclSubject *KeychainPromptAclSubject::Maker::make(const TypedList &list) const
 192 {
 193         switch (list.length()) {
 194 #if ACCEPT_LEGACY_FORM
 195         case 2: // legacy case: just description
 196                 {
 197                         ListElement *params[1];
 198                         crack(list, 1, params, CSSM_LIST_ELEMENT_DATUM);
 199                         return new KeychainPromptAclSubject(*params[0], defaultSelector);
 200                 }
 201 #endif //ACCEPT_LEGACY_FORM
 202         case 3: // standard case: selector + description
 203                 {
 204                         ListElement *params[2];
 205                         crack(list, 2, params, CSSM_LIST_ELEMENT_DATUM, CSSM_LIST_ELEMENT_DATUM);
 206                         return new KeychainPromptAclSubject(*params[1],
 207                                 *params[0]->data().interpretedAs<CSSM_ACL_KEYCHAIN_PROMPT_SELECTOR>(CSSM_ERRCODE_INVALID_ACL_SUBJECT_VALUE));
 208                 }
 209         default:
 210                 CssmError::throwMe(CSSM_ERRCODE_INVALID_ACL_SUBJECT_VALUE);
 211         }
 212 }
 213
 214 KeychainPromptAclSubject *KeychainPromptAclSubject::Maker::make(Version version,
 215         Reader &pub, Reader &) const
 216 {
 217         CSSM_ACL_KEYCHAIN_PROMPT_SELECTOR selector;
 218         const char *description;
 219         switch (version) {
 220         case pumaVersion:
 221                 selector = defaultSelector;
 222                 pub(description);
 223                 break;
 224         case jaguarVersion:
 225                 pub(selector);
 226                 selector.version = n2h(selector.version);
 227                 selector.flags = n2h(selector.flags);
 228                 pub(description);
 229                 break;
 230         default:
 231                 CssmError::throwMe(CSSM_ERRCODE_INVALID_ACL_SUBJECT_VALUE);
 232         }
 233         return new KeychainPromptAclSubject(description, selector);
 234 }
 235
 236 KeychainPromptAclSubject::KeychainPromptAclSubject(string descr,
 237         const CSSM_ACL_KEYCHAIN_PROMPT_SELECTOR &sel)
 238         : SimpleAclSubject(CSSM_ACL_SUBJECT_TYPE_KEYCHAIN_PROMPT),
 239         selector(sel), description(descr)
 240 {
 241         // check selector version
 242         if (selector.version != CSSM_ACL_KEYCHAIN_PROMPT_CURRENT_VERSION)
 243                 CssmError::throwMe(CSSM_ERRCODE_INVALID_ACL_SUBJECT_VALUE);
 244
 245         // always use the latest binary version
 246         version(currentVersion);
 247 }
 248
 249
 250 //
 251 // Export the subject to a memory blob
 252 //
 253 void KeychainPromptAclSubject::exportBlob(Writer::Counter &pub, Writer::Counter &priv)
 254 {
 255         if (version() != 0) {
 256                 selector.version = h2n (selector.version);
 257                 selector.flags = h2n (selector.flags);
 258                 pub(selector);
 259         }
 260
 261     pub.insert(description.size() + 1);
 262 }
 263
 264 void KeychainPromptAclSubject::exportBlob(Writer &pub, Writer &priv)
 265 {
 266         if (version() != 0) {
 267                 selector.version = h2n (selector.version);
 268                 selector.flags = h2n (selector.flags);
 269                 pub(selector);
 270         }
 271     pub(description.c_str());
 272 }
 273
 274
 275 #ifdef DEBUGDUMP
 276
 277 void KeychainPromptAclSubject::debugDump() const
 278 {
 279         Debug::dump("KeychainPrompt:%s(%s)",
 280                 description.c_str(),
 281                 (selector.flags & CSSM_ACL_KEYCHAIN_PROMPT_REQUIRE_PASSPHRASE) ? "passphrase" : "standard");
 282 }
 283
 284 #endif //DEBUGDUMP