OSX/libsecurity_apple_csp/lib/RSA_DSA_signature.cpp

   1 /*
   2  * Copyright (c) 2000-2001,2011-2012,2014 Apple Inc. All Rights Reserved.
   3  *
   4  * The contents of this file constitute Original Code as defined in and are
   5  * subject to the Apple Public Source License Version 1.2 (the 'License').
   6  * You may not use this file except in compliance with the License. Please obtain
   7  * a copy of the License at http://www.apple.com/publicsource and read it before
   8  * using this file.
   9  *
  10  * This Original Code and all software distributed under the License are
  11  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
  12  * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
  13  * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
  14  * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
  15  * specific language governing rights and limitations under the License.
  16  */
  17
  18
  19 /*
  20  * RSA_DSA_signature.cpp - openssl-based signature classes.
  21  */
  22
  23 #include "RSA_DSA_signature.h"
  24 #include "RSA_DSA_utils.h"
  25 #include <stdexcept>
  26 #include <assert.h>
  27 #include <security_utilities/debugging.h>
  28 #include <security_cdsa_utilities/cssmdata.h>
  29 #include <opensslUtils/opensslUtils.h>
  30 #include <opensslUtils/opensslAsn1.h>
  31
  32 #define rsaSigDebug(args...)    secdebug("rsaSig", ## args)
  33
  34 static ModuleNexus<Mutex> gMutex;
  35
  36 RSASigner::~RSASigner()
  37 {
  38         StLock<Mutex> _(gMutex());
  39         if(mWeMallocdRsaKey) {
  40                 assert(mRsaKey != NULL);
  41                 RSA_free(mRsaKey);
  42                 mRsaKey = NULL;
  43                 mWeMallocdRsaKey = false;
  44         }
  45 }
  46
  47 /* reusable init */
  48 void RSASigner::signerInit(
  49         const Context   &context,
  50         bool                    isSigning)
  51 {
  52         StLock<Mutex> _(gMutex());
  53
  54         setIsSigning(isSigning);
  55         keyFromContext(context);
  56
  57         /* optional padding attribute */
  58         uint32 padding;
  59         bool padPresent = context.getInt(CSSM_ATTRIBUTE_PADDING, padding);
  60         if(padPresent) {
  61                 /* padding specified in context, convert to openssl style */
  62                 switch(padding) {
  63                         case CSSM_PADDING_NONE:
  64                                 mPadding = RSA_NO_PADDING;
  65                                 break;
  66                         case CSSM_PADDING_PKCS1:
  67                                 mPadding = RSA_PKCS1_PADDING;
  68                                 break;
  69                         default:
  70                                 CssmError::throwMe(CSSMERR_CSP_INVALID_ATTR_PADDING);
  71                 }
  72         }
  73
  74         /* optional blinding attribute */
  75         uint32 blinding = context.getInt(CSSM_ATTRIBUTE_RSA_BLINDING);
  76         if(blinding) {
  77                 if(RSA_blinding_on(mRsaKey, NULL) <= 0) {
  78                         /* actually no legit failures */
  79                         CssmError::throwMe(CSSMERR_CSP_INTERNAL_ERROR);
  80                 }
  81         }
  82         else {
  83                 RSA_blinding_off(mRsaKey);
  84         }
  85
  86         setInitFlag(true);
  87 }
  88
  89 /* sign */
  90 void RSASigner::sign(
  91         const void              *data,
  92         size_t                  dataLen,
  93         void                    *sig,
  94         size_t                  *sigLen)        /* IN/OUT */
  95 {
  96         StLock<Mutex> _(gMutex());
  97
  98         if(mRsaKey == NULL) {
  99                 CssmError::throwMe(CSSMERR_CSP_INTERNAL_ERROR);
 100         }
 101
 102         /* get encoded digest info */
 103         CssmAutoData    encodedInfo(alloc());
 104         int irtn = generateDigestInfo(data,
 105                 dataLen,
 106                 digestAlg(),
 107                 encodedInfo,
 108                 RSA_size(mRsaKey));
 109         if(irtn) {
 110                 rsaSigDebug("***digestInfo error\n");
 111                 throwOpensslErr(irtn);
 112         }
 113
 114         /* signature := encrypted digest info */
 115         irtn = RSA_private_encrypt((int)encodedInfo.length(),
 116                 (unsigned char *)encodedInfo.data(),
 117                 (unsigned char *)sig,
 118                 mRsaKey,
 119                 mPadding);
 120         if(irtn < 0) {
 121                 throwRsaDsa("RSA_private_encrypt");
 122         }
 123         if((unsigned)irtn > *sigLen) {
 124                 rsaSigDebug("RSA_private_encrypt: sig overflow");
 125                 CssmError::throwMe(CSSMERR_CSP_OUTPUT_LENGTH_ERROR);
 126         }
 127         *sigLen = (unsigned)irtn;
 128 }
 129
 130 /* verify */
 131 void RSASigner::verify(
 132         const void              *data,
 133         size_t                  dataLen,
 134         const void              *sig,
 135         size_t                  sigLen)
 136 {
 137         StLock<Mutex> _(gMutex());
 138
 139         const char *op = NULL;
 140         bool throwSigVerify = false;
 141
 142         if(mRsaKey == NULL) {
 143                 CssmError::throwMe(CSSMERR_CSP_INTERNAL_ERROR);
 144         }
 145
 146         /* get encoded digest info */
 147         CssmAutoData    encodedInfo(alloc());
 148         int irtn = generateDigestInfo(data,
 149                 dataLen,
 150                 digestAlg(),
 151                 encodedInfo,
 152                 RSA_size(mRsaKey));
 153         if(irtn) {
 154                 rsaSigDebug("***digestInfo error\n");
 155                 CssmError::throwMe(/* FIXME */CSSMERR_CSP_INTERNAL_ERROR);
 156         }
 157
 158         /* malloc decrypted signature */
 159         unsigned char *decryptSig =
 160                 (unsigned char *)alloc().malloc(RSA_size(mRsaKey));
 161         unsigned decryptSigLen;
 162
 163         /* signature should be encrypted digest info; decrypt the signature  */
 164         irtn = RSA_public_decrypt((int)sigLen,
 165                 (unsigned char *)sig,
 166                 decryptSig,
 167                 mRsaKey,
 168                 mPadding);
 169         if(irtn < 0) {
 170                 op = "RSA_public_decrypt";
 171                 throwSigVerify = true;
 172                 goto abort;
 173         }
 174         decryptSigLen = (unsigned)irtn;
 175         if(decryptSigLen != encodedInfo.length()) {
 176                 rsaSigDebug("***Decrypted signature length error (exp %ld, got %d)\n",
 177                         encodedInfo.length(), decryptSigLen);
 178                 throwSigVerify = true;
 179                 op = "RSA Sig length check";
 180                 goto abort;
 181         }
 182         if(memcmp(decryptSig, encodedInfo.data(), decryptSigLen)) {
 183                 rsaSigDebug("***Signature miscompare\n");
 184                 throwSigVerify = true;
 185                 op = "RSA Sig miscompare";
 186                 goto abort;
 187         }
 188         else {
 189                 irtn = 0;
 190         }
 191 abort:
 192         if(decryptSig != NULL) {
 193                 alloc().free(decryptSig);
 194         }
 195         if(throwSigVerify) {
 196                 clearOpensslErrors();
 197                 CssmError::throwMe(CSSMERR_CSP_VERIFY_FAILED);
 198         }
 199 }
 200
 201 /* works for both, but only used for signing */
 202 size_t RSASigner::maxSigSize()
 203 {
 204         StLock<Mutex> _(gMutex());
 205         if(mRsaKey == NULL) {
 206                 return 0;
 207         }
 208         return RSA_size(mRsaKey);
 209 }
 210
 211 /*
 212  * obtain key from context, validate, convert to native RSA key
 213  */
 214 void RSASigner::keyFromContext(
 215         const Context   &context)
 216 {
 217         if(initFlag() && (mRsaKey != NULL)) {
 218                 /* reusing context, OK */
 219                 return;
 220         }
 221
 222         CSSM_KEYCLASS   keyClass;
 223         CSSM_KEYUSE             keyUse;
 224         if(isSigning()) {
 225                 /* signing with private key */
 226                 keyClass = CSSM_KEYCLASS_PRIVATE_KEY;
 227                 keyUse   = CSSM_KEYUSE_SIGN;
 228         }
 229         else {
 230                 /* verifying with public key */
 231                 keyClass = CSSM_KEYCLASS_PUBLIC_KEY;
 232                 keyUse   = CSSM_KEYUSE_VERIFY;
 233         }
 234         if(mRsaKey == NULL) {
 235                 CSSM_DATA label = {0, NULL};
 236                 mRsaKey = contextToRsaKey(context,
 237                         mSession,
 238                         keyClass,
 239                         keyUse,
 240                         mWeMallocdRsaKey,
 241                         label);
 242                 /* cannot have label param for signing */
 243                 assert(label.Data == NULL);
 244         }
 245 }
 246
 247 DSASigner::~DSASigner()
 248 {
 249         if(mWeMallocdDsaKey) {
 250                 assert(mDsaKey != NULL);
 251                 DSA_free(mDsaKey);
 252                 mDsaKey = NULL;
 253                 mWeMallocdDsaKey = false;
 254         }
 255 }
 256
 257 /* reusable init */
 258 void DSASigner::signerInit(
 259         const Context   &context,
 260         bool                    isSigning)
 261 {
 262         setIsSigning(isSigning);
 263         keyFromContext(context);
 264         setInitFlag(true);
 265 }
 266
 267 /* sign */
 268 void DSASigner::sign(
 269         const void              *data,
 270         size_t                  dataLen,
 271         void                    *sig,
 272         size_t                  *sigLen)        /* IN/OUT */
 273 {
 274         if(mDsaKey == NULL) {
 275                 CssmError::throwMe(CSSMERR_CSP_INTERNAL_ERROR);
 276         }
 277         if(mDsaKey->priv_key == NULL) {
 278                 CssmError::throwMe(CSSMERR_CSP_INVALID_KEY_CLASS);
 279         }
 280
 281         /* get signature in internal format */
 282         DSA_SIG *dsaSig = DSA_do_sign((unsigned char *)data, (int)dataLen, mDsaKey);
 283         if(dsaSig == NULL) {
 284                 throwRsaDsa("DSA_do_sign");
 285         }
 286
 287         /* DER encode the signature */
 288         CssmAutoData    encodedSig(alloc());
 289         int irtn = DSASigEncode(dsaSig, encodedSig);
 290         if(irtn) {
 291                 throwRsaDsa("DSASigEncode");
 292         }
 293         if(encodedSig.length() > *sigLen) {
 294                 throwRsaDsa("DSA sign overflow");
 295         }
 296         memmove(sig, encodedSig.data(), encodedSig.length());
 297         *sigLen = encodedSig.length();
 298         DSA_SIG_free(dsaSig);
 299 }
 300
 301 /* verify */
 302 void DSASigner::verify(
 303         const void              *data,
 304         size_t                  dataLen,
 305         const void              *sig,
 306         size_t                  sigLen)
 307 {
 308         bool                    throwSigVerify = false;
 309         DSA_SIG                 *dsaSig = NULL;
 310         CSSM_RETURN             crtn = CSSM_OK;
 311         int                                     irtn;
 312
 313         if(mDsaKey == NULL) {
 314                 CssmError::throwMe(CSSMERR_CSP_INTERNAL_ERROR);
 315         }
 316         if(mDsaKey->pub_key == NULL) {
 317                 CssmError::throwMe(CSSMERR_CSP_INVALID_KEY_CLASS);
 318         }
 319
 320         /* incoming sig is DER encoded....decode into internal format */
 321         dsaSig = DSA_SIG_new();
 322         crtn = DSASigDecode(dsaSig, sig, (unsigned int)sigLen);
 323         if(crtn) {
 324                 goto abort;
 325         }
 326
 327         irtn = DSA_do_verify((unsigned char *)data, (int)dataLen, dsaSig, mDsaKey);
 328         if(irtn != 1) {
 329                 throwSigVerify = true;
 330         }
 331
 332 abort:
 333         if(dsaSig != NULL) {
 334                 DSA_SIG_free(dsaSig);
 335         }
 336         if(throwSigVerify) {
 337                 clearOpensslErrors();
 338                 CssmError::throwMe(CSSMERR_CSP_VERIFY_FAILED);
 339         }
 340         else if(crtn) {
 341                 CssmError::throwMe(crtn);
 342         }
 343 }
 344
 345 /*
 346  * Works for both, but only used for signing.
 347  * DSA sig is a sequence of two 160-bit integers.
 348  */
 349 size_t DSASigner::maxSigSize()
 350 {
 351         if(mDsaKey == NULL) {
 352                 return 0;
 353         }
 354         size_t outSize;
 355         size_t sizeOfOneInt;
 356
 357         sizeOfOneInt = (160 / 8) +              // the raw contents
 358                                         1 +                             // possible leading zero
 359                                         2;                              // tag + length (assume DER, not BER)
 360         outSize = (2 * sizeOfOneInt) + 5;
 361         return outSize;
 362 }
 363
 364 /*
 365  * obtain key from context, validate, convert to native DSA key
 366  */
 367 void DSASigner::keyFromContext(
 368         const Context   &context)
 369 {
 370         if(initFlag() && (mDsaKey != NULL)) {
 371                 /* reusing context, OK */
 372                 return;
 373         }
 374
 375         CSSM_KEYCLASS   keyClass;
 376         CSSM_KEYUSE             keyUse;
 377         if(isSigning()) {
 378                 /* signing with private key */
 379                 keyClass = CSSM_KEYCLASS_PRIVATE_KEY;
 380                 keyUse   = CSSM_KEYUSE_SIGN;
 381         }
 382         else {
 383                 /* verifying with public key */
 384                 keyClass = CSSM_KEYCLASS_PUBLIC_KEY;
 385                 keyUse   = CSSM_KEYUSE_VERIFY;
 386         }
 387         if(mDsaKey == NULL) {
 388                 mDsaKey = contextToDsaKey(context,
 389                         mSession,
 390                         keyClass,
 391                         keyUse,
 392                         mWeMallocdDsaKey);
 393         }
 394 }