Home | History | Annotate | Download | only in evp
      1 /* Written by Dr Stephen N Henson (steve (at) openssl.org) for the OpenSSL
      2  * project 2006.
      3  */
      4 /* ====================================================================
      5  * Copyright (c) 2006 The OpenSSL Project.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  *
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  *
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in
     16  *    the documentation and/or other materials provided with the
     17  *    distribution.
     18  *
     19  * 3. All advertising materials mentioning features or use of this
     20  *    software must display the following acknowledgment:
     21  *    "This product includes software developed by the OpenSSL Project
     22  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
     23  *
     24  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
     25  *    endorse or promote products derived from this software without
     26  *    prior written permission. For written permission, please contact
     27  *    licensing (at) OpenSSL.org.
     28  *
     29  * 5. Products derived from this software may not be called "OpenSSL"
     30  *    nor may "OpenSSL" appear in their names without prior written
     31  *    permission of the OpenSSL Project.
     32  *
     33  * 6. Redistributions of any form whatsoever must retain the following
     34  *    acknowledgment:
     35  *    "This product includes software developed by the OpenSSL Project
     36  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
     37  *
     38  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
     39  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     40  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     41  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
     42  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     43  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     44  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     45  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     46  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     47  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     48  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
     49  * OF THE POSSIBILITY OF SUCH DAMAGE.
     50  * ====================================================================
     51  *
     52  * This product includes cryptographic software written by Eric Young
     53  * (eay (at) cryptsoft.com).  This product includes software written by Tim
     54  * Hudson (tjh (at) cryptsoft.com). */
     55 
     56 #include <openssl/evp.h>
     57 
     58 #include <openssl/asn1.h>
     59 #include <openssl/asn1t.h>
     60 #include <openssl/bytestring.h>
     61 #include <openssl/digest.h>
     62 #include <openssl/err.h>
     63 #include <openssl/mem.h>
     64 #include <openssl/obj.h>
     65 #include <openssl/rsa.h>
     66 #include <openssl/x509.h>
     67 
     68 #include "../rsa/internal.h"
     69 #include "internal.h"
     70 
     71 
     72 static int rsa_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey) {
     73   uint8_t *encoded;
     74   size_t encoded_len;
     75   if (!RSA_public_key_to_bytes(&encoded, &encoded_len, pkey->pkey.rsa)) {
     76     return 0;
     77   }
     78 
     79   if (!X509_PUBKEY_set0_param(pk, OBJ_nid2obj(EVP_PKEY_RSA), V_ASN1_NULL, NULL,
     80                               encoded, encoded_len)) {
     81     OPENSSL_free(encoded);
     82     return 0;
     83   }
     84 
     85   return 1;
     86 }
     87 
     88 static int rsa_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey) {
     89   const uint8_t *p;
     90   int pklen;
     91   if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, NULL, pubkey)) {
     92     return 0;
     93   }
     94 
     95   /* Estonian IDs issued between September 2014 to September 2015 are
     96    * broken. See https://crbug.com/532048 and https://crbug.com/534766.
     97    *
     98    * TODO(davidben): Switch this to the strict version in March 2016 or when
     99    * Chromium can force client certificates down a different codepath, whichever
    100    * comes first. */
    101   CBS cbs;
    102   CBS_init(&cbs, p, pklen);
    103   RSA *rsa = RSA_parse_public_key_buggy(&cbs);
    104   if (rsa == NULL || CBS_len(&cbs) != 0) {
    105     OPENSSL_PUT_ERROR(EVP, EVP_R_DECODE_ERROR);
    106     RSA_free(rsa);
    107     return 0;
    108   }
    109 
    110   EVP_PKEY_assign_RSA(pkey, rsa);
    111   return 1;
    112 }
    113 
    114 static int rsa_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b) {
    115   return BN_cmp(b->pkey.rsa->n, a->pkey.rsa->n) == 0 &&
    116          BN_cmp(b->pkey.rsa->e, a->pkey.rsa->e) == 0;
    117 }
    118 
    119 static int rsa_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey) {
    120   uint8_t *encoded;
    121   size_t encoded_len;
    122   if (!RSA_private_key_to_bytes(&encoded, &encoded_len, pkey->pkey.rsa)) {
    123     return 0;
    124   }
    125 
    126   /* TODO(fork): const correctness in next line. */
    127   if (!PKCS8_pkey_set0(p8, (ASN1_OBJECT *)OBJ_nid2obj(NID_rsaEncryption), 0,
    128                        V_ASN1_NULL, NULL, encoded, encoded_len)) {
    129     OPENSSL_free(encoded);
    130     OPENSSL_PUT_ERROR(EVP, ERR_R_MALLOC_FAILURE);
    131     return 0;
    132   }
    133 
    134   return 1;
    135 }
    136 
    137 static int rsa_priv_decode(EVP_PKEY *pkey, PKCS8_PRIV_KEY_INFO *p8) {
    138   const uint8_t *p;
    139   int pklen;
    140   if (!PKCS8_pkey_get0(NULL, &p, &pklen, NULL, p8)) {
    141     OPENSSL_PUT_ERROR(EVP, ERR_R_MALLOC_FAILURE);
    142     return 0;
    143   }
    144 
    145   RSA *rsa = RSA_private_key_from_bytes(p, pklen);
    146   if (rsa == NULL) {
    147     OPENSSL_PUT_ERROR(EVP, ERR_R_RSA_LIB);
    148     return 0;
    149   }
    150 
    151   EVP_PKEY_assign_RSA(pkey, rsa);
    152   return 1;
    153 }
    154 
    155 static int rsa_opaque(const EVP_PKEY *pkey) {
    156   return RSA_is_opaque(pkey->pkey.rsa);
    157 }
    158 
    159 static int rsa_supports_digest(const EVP_PKEY *pkey, const EVP_MD *md) {
    160   return RSA_supports_digest(pkey->pkey.rsa, md);
    161 }
    162 
    163 static int int_rsa_size(const EVP_PKEY *pkey) {
    164   return RSA_size(pkey->pkey.rsa);
    165 }
    166 
    167 static int rsa_bits(const EVP_PKEY *pkey) {
    168   return BN_num_bits(pkey->pkey.rsa->n);
    169 }
    170 
    171 static void int_rsa_free(EVP_PKEY *pkey) { RSA_free(pkey->pkey.rsa); }
    172 
    173 static void update_buflen(const BIGNUM *b, size_t *pbuflen) {
    174   size_t i;
    175 
    176   if (!b) {
    177     return;
    178   }
    179 
    180   i = BN_num_bytes(b);
    181   if (*pbuflen < i) {
    182     *pbuflen = i;
    183   }
    184 }
    185 
    186 static int do_rsa_print(BIO *out, const RSA *rsa, int off,
    187                         int include_private) {
    188   char *str;
    189   const char *s;
    190   uint8_t *m = NULL;
    191   int ret = 0, mod_len = 0;
    192   size_t buf_len = 0;
    193 
    194   update_buflen(rsa->n, &buf_len);
    195   update_buflen(rsa->e, &buf_len);
    196 
    197   if (include_private) {
    198     update_buflen(rsa->d, &buf_len);
    199     update_buflen(rsa->p, &buf_len);
    200     update_buflen(rsa->q, &buf_len);
    201     update_buflen(rsa->dmp1, &buf_len);
    202     update_buflen(rsa->dmq1, &buf_len);
    203     update_buflen(rsa->iqmp, &buf_len);
    204 
    205     if (rsa->additional_primes != NULL) {
    206       size_t i;
    207 
    208       for (i = 0; i < sk_RSA_additional_prime_num(rsa->additional_primes);
    209            i++) {
    210         const RSA_additional_prime *ap =
    211             sk_RSA_additional_prime_value(rsa->additional_primes, i);
    212         update_buflen(ap->prime, &buf_len);
    213         update_buflen(ap->exp, &buf_len);
    214         update_buflen(ap->coeff, &buf_len);
    215       }
    216     }
    217   }
    218 
    219   m = (uint8_t *)OPENSSL_malloc(buf_len + 10);
    220   if (m == NULL) {
    221     OPENSSL_PUT_ERROR(EVP, ERR_R_MALLOC_FAILURE);
    222     goto err;
    223   }
    224 
    225   if (rsa->n != NULL) {
    226     mod_len = BN_num_bits(rsa->n);
    227   }
    228 
    229   if (!BIO_indent(out, off, 128)) {
    230     goto err;
    231   }
    232 
    233   if (include_private && rsa->d) {
    234     if (BIO_printf(out, "Private-Key: (%d bit)\n", mod_len) <= 0) {
    235       goto err;
    236     }
    237     str = "modulus:";
    238     s = "publicExponent:";
    239   } else {
    240     if (BIO_printf(out, "Public-Key: (%d bit)\n", mod_len) <= 0) {
    241       goto err;
    242     }
    243     str = "Modulus:";
    244     s = "Exponent:";
    245   }
    246   if (!ASN1_bn_print(out, str, rsa->n, m, off) ||
    247       !ASN1_bn_print(out, s, rsa->e, m, off)) {
    248     goto err;
    249   }
    250 
    251   if (include_private) {
    252     if (!ASN1_bn_print(out, "privateExponent:", rsa->d, m, off) ||
    253         !ASN1_bn_print(out, "prime1:", rsa->p, m, off) ||
    254         !ASN1_bn_print(out, "prime2:", rsa->q, m, off) ||
    255         !ASN1_bn_print(out, "exponent1:", rsa->dmp1, m, off) ||
    256         !ASN1_bn_print(out, "exponent2:", rsa->dmq1, m, off) ||
    257         !ASN1_bn_print(out, "coefficient:", rsa->iqmp, m, off)) {
    258       goto err;
    259     }
    260 
    261     if (rsa->additional_primes != NULL &&
    262         sk_RSA_additional_prime_num(rsa->additional_primes) > 0) {
    263       size_t i;
    264 
    265       if (BIO_printf(out, "otherPrimeInfos:\n") <= 0) {
    266         goto err;
    267       }
    268       for (i = 0; i < sk_RSA_additional_prime_num(rsa->additional_primes);
    269            i++) {
    270         const RSA_additional_prime *ap =
    271             sk_RSA_additional_prime_value(rsa->additional_primes, i);
    272 
    273         if (BIO_printf(out, "otherPrimeInfo (prime %u):\n",
    274                        (unsigned)(i + 3)) <= 0 ||
    275             !ASN1_bn_print(out, "prime:", ap->prime, m, off) ||
    276             !ASN1_bn_print(out, "exponent:", ap->exp, m, off) ||
    277             !ASN1_bn_print(out, "coeff:", ap->coeff, m, off)) {
    278           goto err;
    279         }
    280       }
    281     }
    282   }
    283   ret = 1;
    284 
    285 err:
    286   OPENSSL_free(m);
    287   return ret;
    288 }
    289 
    290 static int rsa_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent,
    291                          ASN1_PCTX *ctx) {
    292   return do_rsa_print(bp, pkey->pkey.rsa, indent, 0);
    293 }
    294 
    295 
    296 static int rsa_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent,
    297                           ASN1_PCTX *ctx) {
    298   return do_rsa_print(bp, pkey->pkey.rsa, indent, 1);
    299 }
    300 
    301 /* Given an MGF1 Algorithm ID decode to an Algorithm Identifier */
    302 static X509_ALGOR *rsa_mgf1_decode(X509_ALGOR *alg) {
    303   const uint8_t *p;
    304   int plen;
    305 
    306   if (alg == NULL || alg->parameter == NULL ||
    307       OBJ_obj2nid(alg->algorithm) != NID_mgf1 ||
    308       alg->parameter->type != V_ASN1_SEQUENCE) {
    309     return NULL;
    310   }
    311 
    312   p = alg->parameter->value.sequence->data;
    313   plen = alg->parameter->value.sequence->length;
    314   return d2i_X509_ALGOR(NULL, &p, plen);
    315 }
    316 
    317 static RSA_PSS_PARAMS *rsa_pss_decode(const X509_ALGOR *alg,
    318                                       X509_ALGOR **pmaskHash) {
    319   const uint8_t *p;
    320   int plen;
    321   RSA_PSS_PARAMS *pss;
    322 
    323   *pmaskHash = NULL;
    324 
    325   if (!alg->parameter || alg->parameter->type != V_ASN1_SEQUENCE) {
    326     return NULL;
    327   }
    328   p = alg->parameter->value.sequence->data;
    329   plen = alg->parameter->value.sequence->length;
    330   pss = d2i_RSA_PSS_PARAMS(NULL, &p, plen);
    331 
    332   if (!pss) {
    333     return NULL;
    334   }
    335 
    336   *pmaskHash = rsa_mgf1_decode(pss->maskGenAlgorithm);
    337 
    338   return pss;
    339 }
    340 
    341 static int rsa_pss_param_print(BIO *bp, RSA_PSS_PARAMS *pss,
    342                                X509_ALGOR *maskHash, int indent) {
    343   int rv = 0;
    344 
    345   if (!pss) {
    346     if (BIO_puts(bp, " (INVALID PSS PARAMETERS)\n") <= 0) {
    347       return 0;
    348     }
    349     return 1;
    350   }
    351 
    352   if (BIO_puts(bp, "\n") <= 0 ||
    353       !BIO_indent(bp, indent, 128) ||
    354       BIO_puts(bp, "Hash Algorithm: ") <= 0) {
    355     goto err;
    356   }
    357 
    358   if (pss->hashAlgorithm) {
    359     if (i2a_ASN1_OBJECT(bp, pss->hashAlgorithm->algorithm) <= 0) {
    360       goto err;
    361     }
    362   } else if (BIO_puts(bp, "sha1 (default)") <= 0) {
    363     goto err;
    364   }
    365 
    366   if (BIO_puts(bp, "\n") <= 0 ||
    367       !BIO_indent(bp, indent, 128) ||
    368       BIO_puts(bp, "Mask Algorithm: ") <= 0) {
    369     goto err;
    370   }
    371 
    372   if (pss->maskGenAlgorithm) {
    373     if (i2a_ASN1_OBJECT(bp, pss->maskGenAlgorithm->algorithm) <= 0 ||
    374         BIO_puts(bp, " with ") <= 0) {
    375       goto err;
    376     }
    377 
    378     if (maskHash) {
    379       if (i2a_ASN1_OBJECT(bp, maskHash->algorithm) <= 0) {
    380         goto err;
    381       }
    382     } else if (BIO_puts(bp, "INVALID") <= 0) {
    383       goto err;
    384     }
    385   } else if (BIO_puts(bp, "mgf1 with sha1 (default)") <= 0) {
    386     goto err;
    387   }
    388   BIO_puts(bp, "\n");
    389 
    390   if (!BIO_indent(bp, indent, 128) ||
    391       BIO_puts(bp, "Salt Length: 0x") <= 0) {
    392     goto err;
    393   }
    394 
    395   if (pss->saltLength) {
    396     if (i2a_ASN1_INTEGER(bp, pss->saltLength) <= 0) {
    397       goto err;
    398     }
    399   } else if (BIO_puts(bp, "14 (default)") <= 0) {
    400     goto err;
    401   }
    402   BIO_puts(bp, "\n");
    403 
    404   if (!BIO_indent(bp, indent, 128) ||
    405       BIO_puts(bp, "Trailer Field: 0x") <= 0) {
    406     goto err;
    407   }
    408 
    409   if (pss->trailerField) {
    410     if (i2a_ASN1_INTEGER(bp, pss->trailerField) <= 0) {
    411       goto err;
    412     }
    413   } else if (BIO_puts(bp, "BC (default)") <= 0) {
    414     goto err;
    415   }
    416   BIO_puts(bp, "\n");
    417 
    418   rv = 1;
    419 
    420 err:
    421   return rv;
    422 }
    423 
    424 static int rsa_sig_print(BIO *bp, const X509_ALGOR *sigalg,
    425                          const ASN1_STRING *sig, int indent, ASN1_PCTX *pctx) {
    426   if (OBJ_obj2nid(sigalg->algorithm) == NID_rsassaPss) {
    427     int rv;
    428     RSA_PSS_PARAMS *pss;
    429     X509_ALGOR *maskHash;
    430 
    431     pss = rsa_pss_decode(sigalg, &maskHash);
    432     rv = rsa_pss_param_print(bp, pss, maskHash, indent);
    433     RSA_PSS_PARAMS_free(pss);
    434     X509_ALGOR_free(maskHash);
    435     if (!rv) {
    436       return 0;
    437     }
    438   } else if (!sig && BIO_puts(bp, "\n") <= 0) {
    439     return 0;
    440   }
    441 
    442   if (sig) {
    443     return X509_signature_dump(bp, sig, indent);
    444   }
    445   return 1;
    446 }
    447 
    448 static int old_rsa_priv_decode(EVP_PKEY *pkey, const uint8_t **pder,
    449                                int derlen) {
    450   RSA *rsa = d2i_RSAPrivateKey(NULL, pder, derlen);
    451   if (rsa == NULL) {
    452     OPENSSL_PUT_ERROR(EVP, ERR_R_RSA_LIB);
    453     return 0;
    454   }
    455   EVP_PKEY_assign_RSA(pkey, rsa);
    456   return 1;
    457 }
    458 
    459 static int old_rsa_priv_encode(const EVP_PKEY *pkey, uint8_t **pder) {
    460   return i2d_RSAPrivateKey(pkey->pkey.rsa, pder);
    461 }
    462 
    463 /* allocate and set algorithm ID from EVP_MD, default SHA1 */
    464 static int rsa_md_to_algor(X509_ALGOR **palg, const EVP_MD *md) {
    465   if (EVP_MD_type(md) == NID_sha1) {
    466     return 1;
    467   }
    468   *palg = X509_ALGOR_new();
    469   if (!*palg) {
    470     return 0;
    471   }
    472   X509_ALGOR_set_md(*palg, md);
    473   return 1;
    474 }
    475 
    476 /* Allocate and set MGF1 algorithm ID from EVP_MD */
    477 static int rsa_md_to_mgf1(X509_ALGOR **palg, const EVP_MD *mgf1md) {
    478   X509_ALGOR *algtmp = NULL;
    479   ASN1_STRING *stmp = NULL;
    480   *palg = NULL;
    481 
    482   if (EVP_MD_type(mgf1md) == NID_sha1) {
    483     return 1;
    484   }
    485   /* need to embed algorithm ID inside another */
    486   if (!rsa_md_to_algor(&algtmp, mgf1md) ||
    487       !ASN1_item_pack(algtmp, ASN1_ITEM_rptr(X509_ALGOR), &stmp)) {
    488     goto err;
    489   }
    490   *palg = X509_ALGOR_new();
    491   if (!*palg) {
    492     goto err;
    493   }
    494   X509_ALGOR_set0(*palg, OBJ_nid2obj(NID_mgf1), V_ASN1_SEQUENCE, stmp);
    495   stmp = NULL;
    496 
    497 err:
    498   ASN1_STRING_free(stmp);
    499   X509_ALGOR_free(algtmp);
    500   if (*palg) {
    501     return 1;
    502   }
    503 
    504   return 0;
    505 }
    506 
    507 /* convert algorithm ID to EVP_MD, default SHA1 */
    508 static const EVP_MD *rsa_algor_to_md(X509_ALGOR *alg) {
    509   const EVP_MD *md;
    510   if (!alg) {
    511     return EVP_sha1();
    512   }
    513   md = EVP_get_digestbyobj(alg->algorithm);
    514   if (md == NULL) {
    515     OPENSSL_PUT_ERROR(EVP, EVP_R_UNKNOWN_DIGEST);
    516   }
    517   return md;
    518 }
    519 
    520 /* convert MGF1 algorithm ID to EVP_MD, default SHA1 */
    521 static const EVP_MD *rsa_mgf1_to_md(X509_ALGOR *alg, X509_ALGOR *maskHash) {
    522   const EVP_MD *md;
    523   if (!alg) {
    524     return EVP_sha1();
    525   }
    526   /* Check mask and lookup mask hash algorithm */
    527   if (OBJ_obj2nid(alg->algorithm) != NID_mgf1) {
    528     OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_MASK_ALGORITHM);
    529     return NULL;
    530   }
    531   if (!maskHash) {
    532     OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_MASK_PARAMETER);
    533     return NULL;
    534   }
    535   md = EVP_get_digestbyobj(maskHash->algorithm);
    536   if (md == NULL) {
    537     OPENSSL_PUT_ERROR(EVP, EVP_R_UNKNOWN_MASK_DIGEST);
    538     return NULL;
    539   }
    540   return md;
    541 }
    542 
    543 /* rsa_ctx_to_pss converts EVP_PKEY_CTX in PSS mode into corresponding
    544  * algorithm parameter, suitable for setting as an AlgorithmIdentifier. */
    545 static ASN1_STRING *rsa_ctx_to_pss(EVP_PKEY_CTX *pkctx) {
    546   const EVP_MD *sigmd, *mgf1md;
    547   RSA_PSS_PARAMS *pss = NULL;
    548   ASN1_STRING *os = NULL;
    549   EVP_PKEY *pk = EVP_PKEY_CTX_get0_pkey(pkctx);
    550   int saltlen, rv = 0;
    551 
    552   if (!EVP_PKEY_CTX_get_signature_md(pkctx, &sigmd) ||
    553       !EVP_PKEY_CTX_get_rsa_mgf1_md(pkctx, &mgf1md) ||
    554       !EVP_PKEY_CTX_get_rsa_pss_saltlen(pkctx, &saltlen)) {
    555     goto err;
    556   }
    557 
    558   if (saltlen == -1) {
    559     saltlen = EVP_MD_size(sigmd);
    560   } else if (saltlen == -2) {
    561     saltlen = EVP_PKEY_size(pk) - EVP_MD_size(sigmd) - 2;
    562     if (((EVP_PKEY_bits(pk) - 1) & 0x7) == 0) {
    563       saltlen--;
    564     }
    565   } else {
    566     goto err;
    567   }
    568 
    569   pss = RSA_PSS_PARAMS_new();
    570   if (!pss) {
    571     goto err;
    572   }
    573 
    574   if (saltlen != 20) {
    575     pss->saltLength = ASN1_INTEGER_new();
    576     if (!pss->saltLength ||
    577         !ASN1_INTEGER_set(pss->saltLength, saltlen)) {
    578       goto err;
    579     }
    580   }
    581 
    582   if (!rsa_md_to_algor(&pss->hashAlgorithm, sigmd) ||
    583       !rsa_md_to_mgf1(&pss->maskGenAlgorithm, mgf1md)) {
    584     goto err;
    585   }
    586 
    587   /* Finally create string with pss parameter encoding. */
    588   if (!ASN1_item_pack(pss, ASN1_ITEM_rptr(RSA_PSS_PARAMS), &os)) {
    589     goto err;
    590   }
    591   rv = 1;
    592 
    593 err:
    594   if (pss) {
    595     RSA_PSS_PARAMS_free(pss);
    596   }
    597   if (rv) {
    598     return os;
    599   }
    600   if (os) {
    601     ASN1_STRING_free(os);
    602   }
    603   return NULL;
    604 }
    605 
    606 /* From PSS AlgorithmIdentifier set public key parameters. */
    607 static int rsa_pss_to_ctx(EVP_MD_CTX *ctx, X509_ALGOR *sigalg, EVP_PKEY *pkey) {
    608   int ret = 0;
    609   int saltlen;
    610   const EVP_MD *mgf1md = NULL, *md = NULL;
    611   RSA_PSS_PARAMS *pss;
    612   X509_ALGOR *maskHash;
    613   EVP_PKEY_CTX *pkctx;
    614 
    615   /* Sanity check: make sure it is PSS */
    616   if (OBJ_obj2nid(sigalg->algorithm) != NID_rsassaPss) {
    617     OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_SIGNATURE_TYPE);
    618     return 0;
    619   }
    620   /* Decode PSS parameters */
    621   pss = rsa_pss_decode(sigalg, &maskHash);
    622   if (pss == NULL) {
    623     OPENSSL_PUT_ERROR(EVP, EVP_R_INVALID_PSS_PARAMETERS);
    624     goto err;
    625   }
    626 
    627   mgf1md = rsa_mgf1_to_md(pss->maskGenAlgorithm, maskHash);
    628   if (!mgf1md) {
    629     goto err;
    630   }
    631   md = rsa_algor_to_md(pss->hashAlgorithm);
    632   if (!md) {
    633     goto err;
    634   }
    635 
    636   saltlen = 20;
    637   if (pss->saltLength) {
    638     saltlen = ASN1_INTEGER_get(pss->saltLength);
    639 
    640     /* Could perform more salt length sanity checks but the main
    641      * RSA routines will trap other invalid values anyway. */
    642     if (saltlen < 0) {
    643       OPENSSL_PUT_ERROR(EVP, EVP_R_INVALID_SALT_LENGTH);
    644       goto err;
    645     }
    646   }
    647 
    648   /* low-level routines support only trailer field 0xbc (value 1)
    649    * and PKCS#1 says we should reject any other value anyway. */
    650   if (pss->trailerField && ASN1_INTEGER_get(pss->trailerField) != 1) {
    651     OPENSSL_PUT_ERROR(EVP, EVP_R_INVALID_TRAILER);
    652     goto err;
    653   }
    654 
    655   if (!EVP_DigestVerifyInit(ctx, &pkctx, md, NULL, pkey) ||
    656       !EVP_PKEY_CTX_set_rsa_padding(pkctx, RSA_PKCS1_PSS_PADDING) ||
    657       !EVP_PKEY_CTX_set_rsa_pss_saltlen(pkctx, saltlen) ||
    658       !EVP_PKEY_CTX_set_rsa_mgf1_md(pkctx, mgf1md)) {
    659     goto err;
    660   }
    661 
    662   ret = 1;
    663 
    664 err:
    665   RSA_PSS_PARAMS_free(pss);
    666   if (maskHash) {
    667     X509_ALGOR_free(maskHash);
    668   }
    669   return ret;
    670 }
    671 
    672 /* Customised RSA AlgorithmIdentifier handling. This is called when a signature
    673  * is encountered requiring special handling. We currently only handle PSS. */
    674 static int rsa_digest_verify_init_from_algorithm(EVP_MD_CTX *ctx,
    675                                                  X509_ALGOR *sigalg,
    676                                                  EVP_PKEY *pkey) {
    677   /* Sanity check: make sure it is PSS */
    678   if (OBJ_obj2nid(sigalg->algorithm) != NID_rsassaPss) {
    679     OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_SIGNATURE_TYPE);
    680     return 0;
    681   }
    682   return rsa_pss_to_ctx(ctx, sigalg, pkey);
    683 }
    684 
    685 static evp_digest_sign_algorithm_result_t rsa_digest_sign_algorithm(
    686     EVP_MD_CTX *ctx, X509_ALGOR *sigalg) {
    687   int pad_mode;
    688   EVP_PKEY_CTX *pkctx = ctx->pctx;
    689   if (!EVP_PKEY_CTX_get_rsa_padding(pkctx, &pad_mode)) {
    690     return EVP_DIGEST_SIGN_ALGORITHM_ERROR;
    691   }
    692   if (pad_mode == RSA_PKCS1_PSS_PADDING) {
    693     ASN1_STRING *os1 = rsa_ctx_to_pss(pkctx);
    694     if (!os1) {
    695       return EVP_DIGEST_SIGN_ALGORITHM_ERROR;
    696     }
    697     X509_ALGOR_set0(sigalg, OBJ_nid2obj(NID_rsassaPss), V_ASN1_SEQUENCE, os1);
    698     return EVP_DIGEST_SIGN_ALGORITHM_SUCCESS;
    699   }
    700 
    701   /* Other padding schemes use the default behavior. */
    702   return EVP_DIGEST_SIGN_ALGORITHM_DEFAULT;
    703 }
    704 
    705 const EVP_PKEY_ASN1_METHOD rsa_asn1_meth = {
    706   EVP_PKEY_RSA,
    707   EVP_PKEY_RSA,
    708   ASN1_PKEY_SIGPARAM_NULL,
    709 
    710   "RSA",
    711 
    712   rsa_pub_decode,
    713   rsa_pub_encode,
    714   rsa_pub_cmp,
    715   rsa_pub_print,
    716 
    717   rsa_priv_decode,
    718   rsa_priv_encode,
    719   rsa_priv_print,
    720 
    721   rsa_opaque,
    722   rsa_supports_digest,
    723 
    724   int_rsa_size,
    725   rsa_bits,
    726 
    727   0,0,0,0,0,0,
    728 
    729   rsa_sig_print,
    730   int_rsa_free,
    731 
    732   old_rsa_priv_decode,
    733   old_rsa_priv_encode,
    734 
    735   rsa_digest_verify_init_from_algorithm,
    736   rsa_digest_sign_algorithm,
    737 };
    738