src/acl_keychain.cpp

   1 /*
   2  * Copyright (c) 2000-2004,2007 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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  18  * Please see the License for the specific language governing rights and
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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 "osxcodewrap.h"
  51 #include <security_utilities/debugging.h>
  52 #include <security_utilities/logging.h>
  53 #include <security_cdsa_utilities/osxverifier.h>
  54 #include <algorithm>
  55
  56
  57 #define ACCEPT_LEGACY_FORM 1
  58
  59
  60 //
  61 // The default for the selector structure.
  62 //
  63 CSSM_ACL_KEYCHAIN_PROMPT_SELECTOR KeychainPromptAclSubject::defaultSelector = {
  64         CSSM_ACL_KEYCHAIN_PROMPT_CURRENT_VERSION,       // version
  65         0                                                                                       // flags
  66 };
  67
  68
  69 //
  70 // Validate a credential set against this subject.
  71 //
  72 bool KeychainPromptAclSubject::validate(const AclValidationContext &context,
  73     const TypedList &sample) const
  74 {
  75     if (SecurityServerEnvironment *env = context.environment<SecurityServerEnvironment>()) {
  76                 Process &process = Server::process();
  77                 secdebug("kcacl", "Keychain query for process %d (UID %d)", process.pid(), process.uid());
  78
  79                 // assemble the effective validity mode mask
  80                 uint32_t mode = Maker::defaultMode;
  81                 const uint16_t &flags = selector.flags;
  82                 if (flags & CSSM_ACL_KEYCHAIN_PROMPT_UNSIGNED_ACT)
  83                         mode = (mode & ~CSSM_ACL_KEYCHAIN_PROMPT_UNSIGNED) | (flags & CSSM_ACL_KEYCHAIN_PROMPT_UNSIGNED);
  84                 if (flags & CSSM_ACL_KEYCHAIN_PROMPT_INVALID_ACT)
  85                         mode = (mode & ~CSSM_ACL_KEYCHAIN_PROMPT_INVALID) | (flags & CSSM_ACL_KEYCHAIN_PROMPT_INVALID);
  86
  87                 // determine signed/validity status of client, without reference to any particular Code Requirement
  88                 SecCodeRef clientCode = process.currentGuest();
  89                 Server::active().longTermActivity();
  90                 OSStatus validation = clientCode ? SecCodeCheckValidity(clientCode, kSecCSDefaultFlags, NULL) : errSecCSStaticCodeNotFound;
  91                 switch (validation) {
  92                 case noErr:                                                     // client is signed and valid
  93                         secdebug("kcacl", "client is valid, proceeding");
  94                         break;
  95                 case errSecCSUnsigned:                          // client is not signed
  96                         if (!(mode & CSSM_ACL_KEYCHAIN_PROMPT_UNSIGNED)) {
  97                                 secdebug("kcacl", "client is unsigned, suppressing prompt");
  98                                 return false;
  99                         }
 100                         break;
 101                 case errSecCSSignatureFailed:           // client signed but signature is broken
 102                 case errSecCSGuestInvalid:                      // client signed but dynamically invalid
 103                 case errSecCSStaticCodeNotFound:        // client not on disk (or unreadable)
 104                         if (!(mode & CSSM_ACL_KEYCHAIN_PROMPT_INVALID)) {
 105                                 secdebug("kcacl", "client is invalid, suppressing prompt");
 106                                 Syslog::info("suppressing keychain prompt for invalidly signed client %s(%d)",
 107                                         process.getPath().c_str(), process.pid());
 108                                 return false;
 109                         }
 110                         Syslog::info("attempting keychain prompt for invalidly signed client %s(%d)",
 111                                 process.getPath().c_str(), process.pid());
 112                         break;
 113                 default:                                                        // something else went wrong
 114                         secdebug("kcacl", "client validation failed rc=%ld, suppressing prompt", validation);
 115                         return false;
 116                 }
 117
 118                 // At this point, we're committed to try to Pop The Question. Now, how?
 119
 120                 // does the user need to type in the passphrase?
 121         const Database *db = env->database;
 122         bool needPassphrase = db && (selector.flags & CSSM_ACL_KEYCHAIN_PROMPT_REQUIRE_PASSPHRASE);
 123
 124                 // an application (i.e. Keychain Access.app :-) can force this option
 125                 if (clientCode) {
 126                         CFRef<CFDictionaryRef> dict;
 127                         if (!SecCodeCopySigningInformation(clientCode, kSecCSDefaultFlags, &dict.aref()))
 128                                 if (CFDictionaryRef info = CFDictionaryRef(CFDictionaryGetValue(dict, kSecCodeInfoPList)))
 129                                         needPassphrase |=
 130                                                 (CFDictionaryGetValue(info, CFSTR("SecForcePassphrasePrompt")) != NULL);
 131                 }
 132
 133                 // pop The Question
 134                 QueryKeychainUse query(needPassphrase, db);
 135         query.inferHints(Server::process());
 136                 query.addHint(AGENT_HINT_CLIENT_VALIDITY, &validation, sizeof(validation));
 137         if (query.queryUser(db ? db->dbName() : NULL,
 138                         description.c_str(), context.authorization()) != SecurityAgent::noReason)
 139                         return false;
 140
 141                 // process an "always allow..." response
 142                 if (query.remember && clientCode) {
 143                         RefPointer<OSXCode> clientXCode = new OSXCodeWrap(clientCode);
 144                         RefPointer<AclSubject> subject = new CodeSignatureAclSubject(OSXVerifier(clientXCode));
 145                         SecurityServerAcl::addToStandardACL(context, subject);
 146                 }
 147
 148                 // finally, return the actual user response
 149                 return query.allow;
 150     }
 151         return false;        // default to deny without prejudice
 152 }
 153
 154
 155 //
 156 // Make a copy of this subject in CSSM_LIST form
 157 //
 158 CssmList KeychainPromptAclSubject::toList(Allocator &alloc) const
 159 {
 160         // always issue new (non-legacy) form
 161         return TypedList(alloc, CSSM_ACL_SUBJECT_TYPE_KEYCHAIN_PROMPT,
 162                 new(alloc) ListElement(alloc, CssmData::wrap(selector)),
 163         new(alloc) ListElement(alloc, description));
 164 }
 165
 166
 167 //
 168 // Create a KeychainPromptAclSubject
 169 //
 170 uint32_t KeychainPromptAclSubject::Maker::defaultMode;
 171
 172 KeychainPromptAclSubject *KeychainPromptAclSubject::Maker::make(const TypedList &list) const
 173 {
 174         switch (list.length()) {
 175 #if ACCEPT_LEGACY_FORM
 176         case 2: // legacy case: just description
 177                 {
 178                         ListElement *params[1];
 179                         crack(list, 1, params, CSSM_LIST_ELEMENT_DATUM);
 180                         return new KeychainPromptAclSubject(*params[0], defaultSelector);
 181                 }
 182 #endif //ACCEPT_LEGACY_FORM
 183         case 3: // standard case: selector + description
 184                 {
 185                         ListElement *params[2];
 186                         crack(list, 2, params, CSSM_LIST_ELEMENT_DATUM, CSSM_LIST_ELEMENT_DATUM);
 187                         return new KeychainPromptAclSubject(*params[1],
 188                                 *params[0]->data().interpretedAs<CSSM_ACL_KEYCHAIN_PROMPT_SELECTOR>(CSSM_ERRCODE_INVALID_ACL_SUBJECT_VALUE));
 189                 }
 190         default:
 191                 CssmError::throwMe(CSSM_ERRCODE_INVALID_ACL_SUBJECT_VALUE);
 192         }
 193 }
 194
 195 KeychainPromptAclSubject *KeychainPromptAclSubject::Maker::make(Version version,
 196         Reader &pub, Reader &) const
 197 {
 198         CSSM_ACL_KEYCHAIN_PROMPT_SELECTOR selector;
 199         const char *description;
 200         switch (version) {
 201         case pumaVersion:
 202                 selector = defaultSelector;
 203                 pub(description);
 204                 break;
 205         case jaguarVersion:
 206                 pub(selector);
 207                 selector.version = n2h(selector.version);
 208                 selector.flags = n2h(selector.flags);
 209                 pub(description);
 210                 break;
 211         default:
 212                 CssmError::throwMe(CSSM_ERRCODE_INVALID_ACL_SUBJECT_VALUE);
 213         }
 214         return new KeychainPromptAclSubject(description, selector);
 215 }
 216
 217 KeychainPromptAclSubject::KeychainPromptAclSubject(string descr,
 218         const CSSM_ACL_KEYCHAIN_PROMPT_SELECTOR &sel)
 219         : SimpleAclSubject(CSSM_ACL_SUBJECT_TYPE_KEYCHAIN_PROMPT),
 220         selector(sel), description(descr)
 221 {
 222         // check selector version
 223         if (selector.version != CSSM_ACL_KEYCHAIN_PROMPT_CURRENT_VERSION)
 224                 CssmError::throwMe(CSSM_ERRCODE_INVALID_ACL_SUBJECT_VALUE);
 225
 226         // always use the latest binary version
 227         version(currentVersion);
 228 }
 229
 230
 231 //
 232 // Export the subject to a memory blob
 233 //
 234 void KeychainPromptAclSubject::exportBlob(Writer::Counter &pub, Writer::Counter &priv)
 235 {
 236         if (version() != 0) {
 237                 selector.version = h2n (selector.version);
 238                 selector.flags = h2n (selector.flags);
 239                 pub(selector);
 240         }
 241
 242     pub.insert(description.size() + 1);
 243 }
 244
 245 void KeychainPromptAclSubject::exportBlob(Writer &pub, Writer &priv)
 246 {
 247         if (version() != 0) {
 248                 selector.version = h2n (selector.version);
 249                 selector.flags = h2n (selector.flags);
 250                 pub(selector);
 251         }
 252     pub(description.c_str());
 253 }
 254
 255
 256 #ifdef DEBUGDUMP
 257
 258 void KeychainPromptAclSubject::debugDump() const
 259 {
 260         Debug::dump("KeychainPrompt:%s(%s)",
 261                 description.c_str(),
 262                 (selector.flags & CSSM_ACL_KEYCHAIN_PROMPT_REQUIRE_PASSPHRASE) ? "passphrase" : "standard");
 263 }
 264
 265 #endif //DEBUGDUMP