libsecurity_cdsa_utilities/lib/acl_preauth.cpp

   1 /*
   2  * Copyright (c) 2000-2004,2006-2007 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,
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  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
  25 //
  26 // acl_preauth - a subject type for modeling PINs and similar slot-specific
  27 //              pre-authentication schemes.
  28 //
  29 #include "acl_preauth.h"
  30 #include <security_utilities/debugging.h>
  31
  32
  33 namespace Security {
  34 namespace PreAuthorizationAcls {
  35
  36
  37 //
  38 // Origin forms
  39 //
  40 AclSubject *OriginMaker::make(const TypedList &list) const
  41 {
  42         ListElement *args[1];
  43         crack(list, 1, args, CSSM_LIST_ELEMENT_WORDID);
  44                 return new OriginAclSubject(*args[0]);
  45 }
  46
  47 AclSubject *OriginMaker::make(AclSubject::Version version, Reader &pub, Reader &) const
  48 {
  49         // just an integer containing the auth tag
  50         Endian<uint32> auth;
  51         pub(auth);
  52         return new OriginAclSubject(AclAuthorization(auth));
  53 }
  54
  55
  56 //
  57 // Validate the origin form.
  58 // This tries to find the source AclObject and hands the question off to it.
  59 // If anything isn't right, fail the validation.
  60 //
  61 bool OriginAclSubject::validate(const AclValidationContext &ctx) const
  62 {
  63         if (Environment *env = ctx.environment<Environment>())
  64                 if (ObjectAcl *source = env->preAuthSource())
  65                         if (source->validates(mAuthTag, ctx.cred(), ctx.environment()))
  66                                 return true;
  67
  68         // no joy (the sad default)
  69         return false;
  70 }
  71
  72
  73 CssmList OriginAclSubject::toList(Allocator &alloc) const
  74 {
  75         return TypedList(alloc, CSSM_ACL_SUBJECT_TYPE_PREAUTH,
  76                 new(alloc) ListElement(mAuthTag));
  77 }
  78
  79 OriginAclSubject::OriginAclSubject(AclAuthorization auth)
  80         : AclSubject(CSSM_ACL_SUBJECT_TYPE_PREAUTH), mAuthTag(auth)
  81 {
  82         if (auth < CSSM_ACL_AUTHORIZATION_PREAUTH_BASE || auth >= CSSM_ACL_AUTHORIZATION_PREAUTH_END)
  83                 CssmError::throwMe(CSSM_ERRCODE_INVALID_ACL_SUBJECT_VALUE);
  84 }
  85
  86
  87 //
  88 // Origin exported form is just a four-byte integer (preauth authorization tag)
  89 //
  90 void OriginAclSubject::exportBlob(Writer::Counter &pub, Writer::Counter &priv)
  91 {
  92         Endian<uint32> auth = mAuthTag;
  93         pub(auth);
  94 }
  95
  96 void OriginAclSubject::exportBlob(Writer &pub, Writer &priv)
  97 {
  98         Endian<uint32> auth = mAuthTag;
  99         pub(auth);
 100 }
 101
 102
 103 //
 104 // Now for the other side of the coin.
 105 // SourceAclSubjects describe the unusual side (for ACL management) of this game.
 106 // The AclSubject of a preauth source MUST be of PREAUTH_SOURCE type. This subject
 107 // contains the actual validation conditions as a sub-subject, and may provide
 108 // additional information to represent known state of the preauth system.
 109 //
 110 // Think of the extra data in a PreAuthSource ACL as "current state informational"
 111 // that only exists internally, and in the CssmList view. It does not get put into
 112 // persistent (externalized) ACL storage at all. (After all, there's nothing persistent
 113 // about it.)
 114 //
 115 AclSubject *SourceMaker::make(const TypedList &list) const
 116 {
 117         // minimum requirement: item[1] = sub-subject (sublist)
 118         if (list.length() < 2)
 119         CssmError::throwMe(CSSM_ERRCODE_INVALID_ACL_SUBJECT_VALUE);
 120         ListElement &sub = list[1];
 121         RefPointer<AclSubject> subSubject = ObjectAcl::make(sub);
 122
 123         // anything else is interpreted as tracking state (defaulted if missing)
 124         switch (list.length()) {
 125         case 2:         // no tracking state
 126                 return new SourceAclSubject(subSubject);
 127         case 3:
 128                 if (list[2].type() == CSSM_LIST_ELEMENT_WORDID)
 129                         return new SourceAclSubject(subSubject, list[2]);
 130                 // fall through
 131         default:
 132                 CssmError::throwMe(CSSM_ERRCODE_INVALID_ACL_SUBJECT_VALUE);
 133         }
 134 }
 135
 136 AclSubject *SourceMaker::make(AclSubject::Version version, Reader &pub, Reader &priv) const
 137 {
 138         // external form does not contain tracking state - defaults to unknown
 139         RefPointer<AclSubject> subSubject = ObjectAcl::importSubject(pub, priv);
 140         return new SourceAclSubject(subSubject);
 141 }
 142
 143
 144 //
 145 // Source validation uses its own home-cooked validation context.
 146 //
 147 class SourceValidationContext : public AclValidationContext {
 148 public:
 149         SourceValidationContext(const AclValidationContext &base)
 150                 : AclValidationContext(base), mCredTag(base.entryTag()) { }
 151
 152         uint32 count() const    { return cred() ? cred()->samples().length() : 0; }
 153         uint32 size() const             { return count(); }
 154         const TypedList &sample(uint32 n) const
 155         { assert(n < count()); return cred()->samples()[n]; }
 156
 157         const char *credTag() const { return mCredTag; }        // override
 158
 159         void matched(const TypedList *) const { }       //@@@ prelim
 160
 161 private:
 162         const char *mCredTag;
 163 };
 164
 165 bool SourceAclSubject::SourceAclSubject::validate(const AclValidationContext &baseCtx) const
 166 {
 167         // try to authenticate our sub-subject
 168         if (Environment *env = baseCtx.environment<Environment>()) {
 169                 AclAuthorization auth = baseCtx.authorization();
 170                 if (!CSSM_ACL_AUTHORIZATION_IS_PREAUTH(auth))   // all muddled up; bail
 171                         CssmError::throwMe(CSSM_ERRCODE_INVALID_ACL_SUBJECT_VALUE);
 172                 uint32 slot = CSSM_ACL_AUTHORIZATION_PREAUTH_SLOT(auth);
 173                 secdebug("preauth", "using state %d@%p", slot, &env->store(this));
 174                 bool &accepted = env->store(this).attachment<AclState>((void *)slot).accepted;
 175                 if (!accepted) {
 176                         secdebug("preauth", "%p needs to authenticate its subject", this);
 177                         SourceValidationContext ctx(baseCtx);
 178                         if (mSourceSubject->validate(ctx)) {
 179                                 secdebug("preauth", "%p pre-authenticated", this);
 180                                 accepted = true;
 181                         }
 182                 }
 183                 return accepted;
 184         }
 185         return false;
 186 }
 187
 188
 189 CssmList SourceAclSubject::toList(Allocator &alloc) const
 190 {
 191         return TypedList(alloc, CSSM_ACL_SUBJECT_TYPE_PREAUTH_SOURCE,
 192                 new(alloc) ListElement(mSourceSubject->toList(alloc)));
 193 }
 194
 195
 196 SourceAclSubject::SourceAclSubject(AclSubject *subSubject, CSSM_ACL_PREAUTH_TRACKING_STATE state)
 197         : AclSubject(CSSM_ACL_SUBJECT_TYPE_PREAUTH),
 198           mSourceSubject(subSubject)
 199 {
 200 }
 201
 202
 203 //
 204 // Export the subject to a memory blob
 205 //
 206 void SourceAclSubject::exportBlob(Writer::Counter &pub, Writer::Counter &priv)
 207 {
 208         mSourceSubject->exportBlob(pub, priv);
 209 }
 210
 211 void SourceAclSubject::exportBlob(Writer &pub, Writer &priv)
 212 {
 213         mSourceSubject->exportBlob(pub, priv);
 214         // tracking state is not exported
 215 }
 216
 217
 218 #ifdef DEBUGDUMP
 219
 220 void OriginAclSubject::debugDump() const
 221 {
 222         Debug::dump("Preauth(to slot %d)", mAuthTag - CSSM_ACL_AUTHORIZATION_PREAUTH_BASE);
 223 }
 224
 225 void SourceAclSubject::debugDump() const
 226 {
 227         Debug::dump("Preauth source: ");
 228         if (mSourceSubject)
 229                 mSourceSubject->debugDump();
 230         else
 231                 Debug::dump("NULL?");
 232 }
 233
 234 #endif //DEBUGDUMP
 235
 236
 237 }       //  namespace PreAuthorizationAcls
 238 }       //  namespace Security