OSX/libsecurity_smime/lib/cmsencdata.c

   1 /*
   2  * The contents of this file are subject to the Mozilla Public
   3  * License Version 1.1 (the "License"); you may not use this file
   4  * except in compliance with the License. You may obtain a copy of
   5  * the License at http://www.mozilla.org/MPL/
   6  *
   7  * Software distributed under the License is distributed on an "AS
   8  * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
   9  * implied. See the License for the specific language governing
  10  * rights and limitations under the License.
  11  *
  12  * The Original Code is the Netscape security libraries.
  13  *
  14  * The Initial Developer of the Original Code is Netscape
  15  * Communications Corporation.  Portions created by Netscape are
  16  * Copyright (C) 1994-2000 Netscape Communications Corporation.  All
  17  * Rights Reserved.
  18  *
  19  * Contributor(s):
  20  *
  21  * Alternatively, the contents of this file may be used under the
  22  * terms of the GNU General Public License Version 2 or later (the
  23  * "GPL"), in which case the provisions of the GPL are applicable
  24  * instead of those above.  If you wish to allow use of your
  25  * version of this file only under the terms of the GPL and not to
  26  * allow others to use your version of this file under the MPL,
  27  * indicate your decision by deleting the provisions above and
  28  * replace them with the notice and other provisions required by
  29  * the GPL.  If you do not delete the provisions above, a recipient
  30  * may use your version of this file under either the MPL or the
  31  * GPL.
  32  */
  33
  34 /*
  35  * CMS encryptedData methods.
  36  */
  37
  38 #include <Security/SecCmsEncryptedData.h>
  39
  40 #include <Security/SecCmsContentInfo.h>
  41
  42 #include "cmslocal.h"
  43
  44 #include "secitem.h"
  45 #include "secoid.h"
  46 #include <security_asn1/secasn1.h>
  47 #include <security_asn1/secerr.h>
  48
  49 /*
  50  * SecCmsEncryptedDataCreate - create an empty encryptedData object.
  51  *
  52  * "algorithm" specifies the bulk encryption algorithm to use.
  53  * "keysize" is the key size.
  54  *
  55  * An error results in a return value of NULL and an error set.
  56  * (Retrieve specific errors via PORT_GetError()/XP_GetError().)
  57  */
  58 SecCmsEncryptedDataRef
  59 SecCmsEncryptedDataCreate(SecCmsMessageRef cmsg, SECOidTag algorithm, int keysize)
  60 {
  61     void *mark;
  62     SecCmsEncryptedDataRef encd;
  63     PLArenaPool *poolp;
  64     SECAlgorithmID *pbe_algid;
  65     OSStatus rv;
  66
  67     poolp = cmsg->poolp;
  68
  69     mark = PORT_ArenaMark(poolp);
  70
  71     encd = (SecCmsEncryptedDataRef)PORT_ArenaZAlloc(poolp, sizeof(SecCmsEncryptedData));
  72     if (encd == NULL)
  73         goto loser;
  74
  75     encd->cmsg = cmsg;
  76
  77     /* version is set in SecCmsEncryptedDataEncodeBeforeStart() */
  78
  79     switch (algorithm) {
  80     /* XXX hmmm... hardcoded algorithms? */
  81     case SEC_OID_RC2_CBC:
  82     case SEC_OID_DES_EDE3_CBC:
  83     case SEC_OID_DES_CBC:
  84         rv = SecCmsContentInfoSetContentEncAlg((SecArenaPoolRef)poolp, &(encd->contentInfo), algorithm, NULL, keysize);
  85         break;
  86     default:
  87         /* Assume password-based-encryption.  At least, try that. */
  88 #if 1
  89         // @@@ Fix me
  90         pbe_algid = NULL;
  91 #else
  92         pbe_algid = PK11_CreatePBEAlgorithmID(algorithm, 1, NULL);
  93 #endif
  94         if (pbe_algid == NULL) {
  95             rv = SECFailure;
  96             break;
  97         }
  98         rv = SecCmsContentInfoSetContentEncAlgID((SecArenaPoolRef)poolp, &(encd->contentInfo), pbe_algid, keysize);
  99         SECOID_DestroyAlgorithmID (pbe_algid, PR_TRUE);
 100         break;
 101     }
 102     if (rv != SECSuccess)
 103         goto loser;
 104
 105     PORT_ArenaUnmark(poolp, mark);
 106     return encd;
 107
 108 loser:
 109     PORT_ArenaRelease(poolp, mark);
 110     return NULL;
 111 }
 112
 113 /*
 114  * SecCmsEncryptedDataDestroy - destroy an encryptedData object
 115  */
 116 void
 117 SecCmsEncryptedDataDestroy(SecCmsEncryptedDataRef encd)
 118 {
 119     /* everything's in a pool, so don't worry about the storage */
 120     SecCmsContentInfoDestroy(&(encd->contentInfo));
 121     return;
 122 }
 123
 124 /*
 125  * SecCmsEncryptedDataGetContentInfo - return pointer to encryptedData object's contentInfo
 126  */
 127 SecCmsContentInfoRef
 128 SecCmsEncryptedDataGetContentInfo(SecCmsEncryptedDataRef encd)
 129 {
 130     return &(encd->contentInfo);
 131 }
 132
 133 /*
 134  * SecCmsEncryptedDataEncodeBeforeStart - do all the necessary things to a EncryptedData
 135  *     before encoding begins.
 136  *
 137  * In particular:
 138  *  - set the correct version value.
 139  *  - get the encryption key
 140  */
 141 OSStatus
 142 SecCmsEncryptedDataEncodeBeforeStart(SecCmsEncryptedDataRef encd)
 143 {
 144     int version;
 145     SecSymmetricKeyRef bulkkey = NULL;
 146     CSSM_DATA_PTR dummy;
 147     SecCmsContentInfoRef cinfo = &(encd->contentInfo);
 148
 149     if (SecCmsArrayIsEmpty((void **)encd->unprotectedAttr))
 150         version = SEC_CMS_ENCRYPTED_DATA_VERSION;
 151     else
 152         version = SEC_CMS_ENCRYPTED_DATA_VERSION_UPATTR;
 153
 154     dummy = SEC_ASN1EncodeInteger (encd->cmsg->poolp, &(encd->version), version);
 155     if (dummy == NULL)
 156         return SECFailure;
 157
 158     /* now get content encryption key (bulk key) by using our cmsg callback */
 159     if (encd->cmsg->decrypt_key_cb)
 160         bulkkey = (*encd->cmsg->decrypt_key_cb)(encd->cmsg->decrypt_key_cb_arg,
 161                     SecCmsContentInfoGetContentEncAlg(cinfo));
 162     if (bulkkey == NULL)
 163         return SECFailure;
 164
 165     /* store the bulk key in the contentInfo so that the encoder can find it */
 166     SecCmsContentInfoSetBulkKey(cinfo, bulkkey);
 167     CFRelease(bulkkey); /* This assumes the decrypt_key_cb hands us a copy of the key --mb */
 168
 169     return SECSuccess;
 170 }
 171
 172 /*
 173  * SecCmsEncryptedDataEncodeBeforeData - set up encryption
 174  */
 175 OSStatus
 176 SecCmsEncryptedDataEncodeBeforeData(SecCmsEncryptedDataRef encd)
 177 {
 178     SecCmsContentInfoRef cinfo;
 179     SecSymmetricKeyRef bulkkey;
 180     SECAlgorithmID *algid;
 181
 182     cinfo = &(encd->contentInfo);
 183
 184     /* find bulkkey and algorithm - must have been set by SecCmsEncryptedDataEncodeBeforeStart */
 185     bulkkey = SecCmsContentInfoGetBulkKey(cinfo);
 186     if (bulkkey == NULL)
 187         return SECFailure;
 188     algid = SecCmsContentInfoGetContentEncAlg(cinfo);
 189     if (algid == NULL)
 190         return SECFailure;
 191
 192     /* this may modify algid (with IVs generated in a token).
 193      * it is therefore essential that algid is a pointer to the "real" contentEncAlg,
 194      * not just to a copy */
 195     cinfo->ciphcx = SecCmsCipherContextStartEncrypt(encd->cmsg->poolp, bulkkey, algid);
 196     CFRelease(bulkkey);
 197     if (cinfo->ciphcx == NULL)
 198         return SECFailure;
 199
 200     return SECSuccess;
 201 }
 202
 203 /*
 204  * SecCmsEncryptedDataEncodeAfterData - finalize this encryptedData for encoding
 205  */
 206 OSStatus
 207 SecCmsEncryptedDataEncodeAfterData(SecCmsEncryptedDataRef encd)
 208 {
 209     if (encd->contentInfo.ciphcx) {
 210         SecCmsCipherContextDestroy(encd->contentInfo.ciphcx);
 211         encd->contentInfo.ciphcx = NULL;
 212     }
 213
 214     /* nothing to do after data */
 215     return SECSuccess;
 216 }
 217
 218
 219 /*
 220  * SecCmsEncryptedDataDecodeBeforeData - find bulk key & set up decryption
 221  */
 222 OSStatus
 223 SecCmsEncryptedDataDecodeBeforeData(SecCmsEncryptedDataRef encd)
 224 {
 225     SecSymmetricKeyRef bulkkey = NULL;
 226     SecCmsContentInfoRef cinfo;
 227     SECAlgorithmID *bulkalg;
 228     OSStatus rv = SECFailure;
 229
 230     cinfo = &(encd->contentInfo);
 231
 232     bulkalg = SecCmsContentInfoGetContentEncAlg(cinfo);
 233
 234     if (encd->cmsg->decrypt_key_cb == NULL)     /* no callback? no key../ */
 235         goto loser;
 236
 237     bulkkey = (*encd->cmsg->decrypt_key_cb)(encd->cmsg->decrypt_key_cb_arg, bulkalg);
 238     if (bulkkey == NULL)
 239         /* no success finding a bulk key */
 240         goto loser;
 241
 242     SecCmsContentInfoSetBulkKey(cinfo, bulkkey);
 243
 244     cinfo->ciphcx = SecCmsCipherContextStartDecrypt(bulkkey, bulkalg);
 245     if (cinfo->ciphcx == NULL)
 246         goto loser;             /* error has been set by SecCmsCipherContextStartDecrypt */
 247
 248 #if 1
 249     // @@@ Not done yet
 250 #else
 251     /*
 252      * HACK ALERT!!
 253      * For PKCS5 Encryption Algorithms, the bulkkey is actually a different
 254      * structure.  Therefore, we need to set the bulkkey to the actual key
 255      * prior to freeing it.
 256      */
 257     if (SEC_PKCS5IsAlgorithmPBEAlg(bulkalg)) {
 258         SEC_PKCS5KeyAndPassword *keyPwd = (SEC_PKCS5KeyAndPassword *)bulkkey;
 259         bulkkey = keyPwd->key;
 260     }
 261 #endif
 262
 263     /* we are done with (this) bulkkey now. */
 264     CFRelease(bulkkey);
 265
 266     rv = SECSuccess;
 267
 268 loser:
 269     return rv;
 270 }
 271
 272 /*
 273  * SecCmsEncryptedDataDecodeAfterData - finish decrypting this encryptedData's content
 274  */
 275 OSStatus
 276 SecCmsEncryptedDataDecodeAfterData(SecCmsEncryptedDataRef encd)
 277 {
 278     if (encd->contentInfo.ciphcx) {
 279         SecCmsCipherContextDestroy(encd->contentInfo.ciphcx);
 280         encd->contentInfo.ciphcx = NULL;
 281     }
 282
 283     return SECSuccess;
 284 }
 285
 286 /*
 287  * SecCmsEncryptedDataDecodeAfterEnd - finish decoding this encryptedData
 288  */
 289 OSStatus
 290 SecCmsEncryptedDataDecodeAfterEnd(SecCmsEncryptedDataRef encd)
 291 {
 292     /* apply final touches */
 293     return SECSuccess;
 294 }