crypto/evp/p_rsa.c - boringssl - Git at Google

 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2006.
  */
 /* ====================================================================
  * Copyright (c) 2006 The OpenSSL Project.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
  *    the documentation and/or other materials provided with the
  *    distribution.
  *
  * 3. All advertising materials mentioning features or use of this
  *    software must display the following acknowledgment:
  *    "This product includes software developed by the OpenSSL Project
  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  *
  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  *    endorse or promote products derived from this software without
  *    prior written permission. For written permission, please contact
  *    licensing@OpenSSL.org.
  *
  * 5. Products derived from this software may not be called "OpenSSL"
  *    nor may "OpenSSL" appear in their names without prior written
  *    permission of the OpenSSL Project.
  *
  * 6. Redistributions of any form whatsoever must retain the following
  *    acknowledgment:
  *    "This product includes software developed by the OpenSSL Project
  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  *
  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  * ====================================================================
  *
  * This product includes cryptographic software written by Eric Young
  * (eay@cryptsoft.com).  This product includes software written by Tim
  * Hudson (tjh@cryptsoft.com). */

 #include <openssl/evp.h>

 #include <openssl/bn.h>
 #include <openssl/buf.h>
 #include <openssl/digest.h>
 #include <openssl/err.h>
 #include <openssl/mem.h>
 #include <openssl/obj.h>
 #include <openssl/rsa.h>

 #include "../rsa/internal.h"
 #include "internal.h"


 typedef struct {
   /* Key gen parameters */
   int nbits;
   BIGNUM *pub_exp;
   /* RSA padding mode */
   int pad_mode;
   /* message digest */
   const EVP_MD *md;
   /* message digest for MGF1 */
   const EVP_MD *mgf1md;
   /* PSS salt length */
   int saltlen;
   /* tbuf is a buffer which is either NULL, or is the size of the RSA modulus.
    * It's used to store the output of RSA operations. */
   uint8_t *tbuf;
   /* OAEP label */
   uint8_t *oaep_label;
   size_t oaep_labellen;
 } RSA_PKEY_CTX;

 static int pkey_rsa_init(EVP_PKEY_CTX *ctx) {
   RSA_PKEY_CTX *rctx;
   rctx = OPENSSL_malloc(sizeof(RSA_PKEY_CTX));
   if (!rctx) {
     return 0;
   }
   memset(rctx, 0, sizeof(RSA_PKEY_CTX));

   rctx->nbits = 2048;
   rctx->pad_mode = RSA_PKCS1_PADDING;
   rctx->saltlen = -2;

   ctx->data = rctx;

   return 1;
 }

 static int pkey_rsa_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src) {
   RSA_PKEY_CTX *dctx, *sctx;
   if (!pkey_rsa_init(dst)) {
     return 0;
   }
   sctx = src->data;
   dctx = dst->data;
   dctx->nbits = sctx->nbits;
   if (sctx->pub_exp) {
     dctx->pub_exp = BN_dup(sctx->pub_exp);
     if (!dctx->pub_exp) {
       return 0;
     }
   }

   dctx->pad_mode = sctx->pad_mode;
   dctx->md = sctx->md;
   dctx->mgf1md = sctx->mgf1md;
   if (sctx->oaep_label) {
     if (dctx->oaep_label) {
       OPENSSL_free(dctx->oaep_label);
     }
     dctx->oaep_label = BUF_memdup(sctx->oaep_label, sctx->oaep_labellen);
     if (!dctx->oaep_label) {
       return 0;
     }
     dctx->oaep_labellen = sctx->oaep_labellen;
   }

   return 1;
 }

 static void pkey_rsa_cleanup(EVP_PKEY_CTX *ctx) {
   RSA_PKEY_CTX *rctx = ctx->data;

   if (rctx == NULL) {
     return;
   }

   if (rctx->pub_exp) {
     BN_free(rctx->pub_exp);
   }
   if (rctx->tbuf) {
     OPENSSL_free(rctx->tbuf);
   }
   if (rctx->oaep_label) {
     OPENSSL_free(rctx->oaep_label);
   }
   OPENSSL_free(rctx);
 }

 static int setup_tbuf(RSA_PKEY_CTX *ctx, EVP_PKEY_CTX *pk) {
   if (ctx->tbuf) {
     return 1;
   }
   ctx->tbuf = OPENSSL_malloc(EVP_PKEY_size(pk->pkey));
   if (!ctx->tbuf) {
     return 0;
   }
   return 1;
 }

 static int pkey_rsa_sign(EVP_PKEY_CTX *ctx, uint8_t *sig, size_t *siglen,
                          const uint8_t *tbs, size_t tbslen) {
   RSA_PKEY_CTX *rctx = ctx->data;
   RSA *rsa = ctx->pkey->pkey.rsa;
   const size_t key_len = EVP_PKEY_size(ctx->pkey);

   if (!sig) {
     *siglen = key_len;
     return 1;
   }

   if (*siglen < key_len) {
     OPENSSL_PUT_ERROR(EVP, pkey_rsa_sign, EVP_R_BUFFER_TOO_SMALL);
     return 0;
   }

   if (rctx->md) {
     unsigned int out_len;

     if (tbslen != EVP_MD_size(rctx->md)) {
       OPENSSL_PUT_ERROR(EVP, pkey_rsa_sign, EVP_R_INVALID_DIGEST_LENGTH);
       return 0;
     }

     if (EVP_MD_type(rctx->md) == NID_mdc2) {
       OPENSSL_PUT_ERROR(EVP, pkey_rsa_sign, EVP_R_NO_MDC2_SUPPORT);
       return 0;
     }

     switch (rctx->pad_mode) {
       case RSA_PKCS1_PADDING:
         if (!RSA_sign(EVP_MD_type(rctx->md), tbs, tbslen, sig, &out_len, rsa)) {
           return 0;
         }
         *siglen = out_len;
         return 1;

       case RSA_PKCS1_PSS_PADDING:
         if (!setup_tbuf(rctx, ctx) ||
             !RSA_padding_add_PKCS1_PSS_mgf1(rsa, rctx->tbuf, tbs, rctx->md,
                                             rctx->mgf1md, rctx->saltlen) ||
             !RSA_sign_raw(rsa, siglen, sig, *siglen, rctx->tbuf, key_len,
                           RSA_NO_PADDING)) {
           return 0;
         }
         return 1;

       default:
         return 0;
     }
   }

   return RSA_sign_raw(rsa, siglen, sig, *siglen, tbs, tbslen, rctx->pad_mode);
 }

 static int pkey_rsa_verify(EVP_PKEY_CTX *ctx, const uint8_t *sig,
                            size_t siglen, const uint8_t *tbs,
                            size_t tbslen) {
   RSA_PKEY_CTX *rctx = ctx->data;
   RSA *rsa = ctx->pkey->pkey.rsa;
   size_t rslen;
   const size_t key_len = EVP_PKEY_size(ctx->pkey);

   if (rctx->md) {
     switch (rctx->pad_mode) {
       case RSA_PKCS1_PADDING:
         return RSA_verify(EVP_MD_type(rctx->md), tbs, tbslen, sig, siglen, rsa);

       case RSA_PKCS1_PSS_PADDING:
         if (!setup_tbuf(rctx, ctx) ||
             !RSA_verify_raw(rsa, &rslen, rctx->tbuf, key_len, sig, siglen,
                             RSA_NO_PADDING) ||
             !RSA_verify_PKCS1_PSS_mgf1(rsa, tbs, rctx->md, rctx->mgf1md,
                                        rctx->tbuf, rctx->saltlen)) {
           return 0;
         }
         return 1;

       default:
         return 0;
     }
   }

   if (!setup_tbuf(rctx, ctx) ||
       !RSA_verify_raw(rsa, &rslen, rctx->tbuf, key_len, sig, siglen,
                       rctx->pad_mode) ||
       rslen != tbslen ||
       CRYPTO_memcmp(tbs, rctx->tbuf, rslen) != 0) {
     return 0;
   }

   return 1;
 }

 static int pkey_rsa_encrypt(EVP_PKEY_CTX *ctx, uint8_t *out, size_t *outlen,
                             const uint8_t *in, size_t inlen) {
   RSA_PKEY_CTX *rctx = ctx->data;
   RSA *rsa = ctx->pkey->pkey.rsa;
   const size_t key_len = EVP_PKEY_size(ctx->pkey);

   if (!out) {
     *outlen = key_len;
     return 1;
   }

   if (*outlen < key_len) {
     OPENSSL_PUT_ERROR(EVP, pkey_rsa_encrypt, EVP_R_BUFFER_TOO_SMALL);
     return 0;
   }

   if (rctx->pad_mode == RSA_PKCS1_OAEP_PADDING) {
     if (!setup_tbuf(rctx, ctx) ||
         !RSA_padding_add_PKCS1_OAEP_mgf1(rctx->tbuf, key_len, in, inlen,
                                          rctx->oaep_label, rctx->oaep_labellen,
                                          rctx->md, rctx->mgf1md) ||
         !RSA_encrypt(rsa, outlen, out, *outlen, rctx->tbuf, key_len,
                      RSA_NO_PADDING)) {
       return 0;
     }
     return 1;
   }

   return RSA_encrypt(rsa, outlen, out, *outlen, in, inlen, rctx->pad_mode);
 }

 static int pkey_rsa_decrypt(EVP_PKEY_CTX *ctx, uint8_t *out,
                             size_t *outlen, const uint8_t *in,
                             size_t inlen) {
   RSA_PKEY_CTX *rctx = ctx->data;
   RSA *rsa = ctx->pkey->pkey.rsa;
   const size_t key_len = EVP_PKEY_size(ctx->pkey);

   if (!out) {
     *outlen = key_len;
     return 1;
   }

   if (*outlen < key_len) {
     OPENSSL_PUT_ERROR(EVP, pkey_rsa_decrypt, EVP_R_BUFFER_TOO_SMALL);
     return 0;
   }

   if (rctx->pad_mode == RSA_PKCS1_OAEP_PADDING) {
     size_t plaintext_len;
     int message_len;

     if (!setup_tbuf(rctx, ctx) ||
         !RSA_decrypt(rsa, &plaintext_len, rctx->tbuf, key_len, in, inlen,
                      RSA_NO_PADDING)) {
       return 0;
     }

     message_len = RSA_padding_check_PKCS1_OAEP_mgf1(
         out, key_len, rctx->tbuf, plaintext_len, rctx->oaep_label,
         rctx->oaep_labellen, rctx->md, rctx->mgf1md);
     if (message_len < 0) {
       return 0;
     }
     *outlen = message_len;
     return 1;
   }

   return RSA_decrypt(rsa, outlen, out, key_len, in, inlen, rctx->pad_mode);
 }

 static int check_padding_md(const EVP_MD *md, int padding) {
   if (!md) {
     return 1;
   }

   if (padding == RSA_NO_PADDING) {
     OPENSSL_PUT_ERROR(EVP, check_padding_md, EVP_R_INVALID_PADDING_MODE);
     return 0;
   }

   return 1;
 }

 static int is_known_padding(int padding_mode) {
   switch (padding_mode) {
     case RSA_PKCS1_PADDING:
     case RSA_NO_PADDING:
     case RSA_PKCS1_OAEP_PADDING:
     case RSA_PKCS1_PSS_PADDING:
       return 1;
     default:
       return 0;
   }
 }

 static int pkey_rsa_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2) {
   RSA_PKEY_CTX *rctx = ctx->data;
   switch (type) {
     case EVP_PKEY_CTRL_RSA_PADDING:
       if (!is_known_padding(p1) || !check_padding_md(rctx->md, p1) ||
           (p1 == RSA_PKCS1_PSS_PADDING &&
            0 == (ctx->operation & (EVP_PKEY_OP_SIGN | EVP_PKEY_OP_VERIFY))) ||
           (p1 == RSA_PKCS1_OAEP_PADDING &&
            0 == (ctx->operation & EVP_PKEY_OP_TYPE_CRYPT))) {
         OPENSSL_PUT_ERROR(EVP, pkey_rsa_ctrl,
                           EVP_R_ILLEGAL_OR_UNSUPPORTED_PADDING_MODE);
         return -2;
       }
       if ((p1 == RSA_PKCS1_PSS_PADDING || p1 == RSA_PKCS1_OAEP_PADDING) &&
           rctx->md == NULL) {
         rctx->md = EVP_sha1();
       }
       rctx->pad_mode = p1;
       return 1;

     case EVP_PKEY_CTRL_GET_RSA_PADDING:
       *(int *)p2 = rctx->pad_mode;
       return 1;

     case EVP_PKEY_CTRL_RSA_PSS_SALTLEN:
     case EVP_PKEY_CTRL_GET_RSA_PSS_SALTLEN:
       if (rctx->pad_mode != RSA_PKCS1_PSS_PADDING) {
         OPENSSL_PUT_ERROR(EVP, pkey_rsa_ctrl, EVP_R_INVALID_PSS_SALTLEN);
         return -2;
       }
       if (type == EVP_PKEY_CTRL_GET_RSA_PSS_SALTLEN) {
         *(int *)p2 = rctx->saltlen;
       } else {
         if (p1 < -2) {
           return -2;
         }
         rctx->saltlen = p1;
       }
       return 1;

     case EVP_PKEY_CTRL_RSA_KEYGEN_BITS:
       if (p1 < 256) {
         OPENSSL_PUT_ERROR(EVP, pkey_rsa_ctrl, EVP_R_INVALID_KEYBITS);
         return -2;
       }
       rctx->nbits = p1;
       return 1;

     case EVP_PKEY_CTRL_RSA_KEYGEN_PUBEXP:
       if (!p2) {
         return -2;
       }
       BN_free(rctx->pub_exp);
       rctx->pub_exp = p2;
       return 1;

     case EVP_PKEY_CTRL_RSA_OAEP_MD:
     case EVP_PKEY_CTRL_GET_RSA_OAEP_MD:
       if (rctx->pad_mode != RSA_PKCS1_OAEP_PADDING) {
         OPENSSL_PUT_ERROR(EVP, pkey_rsa_ctrl, EVP_R_INVALID_PADDING_MODE);
         return -2;
       }
       if (type == EVP_PKEY_CTRL_GET_RSA_OAEP_MD) {
         *(const EVP_MD **)p2 = rctx->md;
       } else {
         rctx->md = p2;
       }
       return 1;

     case EVP_PKEY_CTRL_MD:
       if (!check_padding_md(p2, rctx->pad_mode)) {
         return 0;
       }
       rctx->md = p2;
       return 1;

     case EVP_PKEY_CTRL_GET_MD:
       *(const EVP_MD **)p2 = rctx->md;
       return 1;

     case EVP_PKEY_CTRL_RSA_MGF1_MD:
     case EVP_PKEY_CTRL_GET_RSA_MGF1_MD:
       if (rctx->pad_mode != RSA_PKCS1_PSS_PADDING &&
           rctx->pad_mode != RSA_PKCS1_OAEP_PADDING) {
         OPENSSL_PUT_ERROR(EVP, pkey_rsa_ctrl, EVP_R_INVALID_MGF1_MD);
         return -2;
       }
       if (type == EVP_PKEY_CTRL_GET_RSA_MGF1_MD) {
         if (rctx->mgf1md) {
           *(const EVP_MD **)p2 = rctx->mgf1md;
         } else {
           *(const EVP_MD **)p2 = rctx->md;
         }
       } else {
         rctx->mgf1md = p2;
       }
       return 1;

     case EVP_PKEY_CTRL_RSA_OAEP_LABEL:
       if (rctx->pad_mode != RSA_PKCS1_OAEP_PADDING) {
         OPENSSL_PUT_ERROR(EVP, pkey_rsa_ctrl, EVP_R_INVALID_PADDING_MODE);
         return -2;
       }
       if (rctx->oaep_label) {
         OPENSSL_free(rctx->oaep_label);
       }
       if (p2 && p1 > 0) {
         /* TODO(fork): this seems wrong. Shouldn't it take a copy of the
          * buffer? */
         rctx->oaep_label = p2;
         rctx->oaep_labellen = p1;
       } else {
         rctx->oaep_label = NULL;
         rctx->oaep_labellen = 0;
       }
       return 1;

     case EVP_PKEY_CTRL_GET_RSA_OAEP_LABEL:
       if (rctx->pad_mode != RSA_PKCS1_OAEP_PADDING) {
         OPENSSL_PUT_ERROR(EVP, pkey_rsa_ctrl, EVP_R_INVALID_PADDING_MODE);
         return -2;
       }
       *(uint8_t **)p2 = rctx->oaep_label;
       return rctx->oaep_labellen;

     case EVP_PKEY_CTRL_DIGESTINIT:
       return 1;

     default:
       return -2;
   }
 }

 static int pkey_rsa_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey) {
   RSA *rsa = NULL;
   RSA_PKEY_CTX *rctx = ctx->data;

   if (!rctx->pub_exp) {
     rctx->pub_exp = BN_new();
     if (!rctx->pub_exp || !BN_set_word(rctx->pub_exp, RSA_F4))
       return 0;
   }
   rsa = RSA_new();
   if (!rsa) {
     return 0;
   }

   if (!RSA_generate_key_ex(rsa, rctx->nbits, rctx->pub_exp, NULL)) {
     RSA_free(rsa);
     return 0;
   }

   EVP_PKEY_assign_RSA(pkey, rsa);
   return 1;
 }

 const EVP_PKEY_METHOD rsa_pkey_meth = {
     EVP_PKEY_RSA,           0 /* flags */,        pkey_rsa_init,
     pkey_rsa_copy,          pkey_rsa_cleanup,     0 /* paramgen_init */,
     0 /* paramgen */,       0 /* keygen_init */,  pkey_rsa_keygen,
     0 /* sign_init */,      pkey_rsa_sign,        0 /* verify_init */,
     pkey_rsa_verify,        0 /* signctx_init */, 0 /* signctx */,
     0 /* verifyctx_init */, 0 /* verifyctx */,    0 /* encrypt_init */,
     pkey_rsa_encrypt,       0 /* decrypt_init */, pkey_rsa_decrypt,
     0 /* derive_init */,    0 /* derive */,       pkey_rsa_ctrl,
 };

 int EVP_PKEY_CTX_set_rsa_padding(EVP_PKEY_CTX *ctx, int padding) {
   return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, -1, EVP_PKEY_CTRL_RSA_PADDING,
                            padding, NULL);
 }

 int EVP_PKEY_CTX_get_rsa_padding(EVP_PKEY_CTX *ctx, int *out_padding) {
   return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, -1, EVP_PKEY_CTRL_GET_RSA_PADDING,
                            0, out_padding);
 }

 int EVP_PKEY_CTX_set_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int salt_len) {
   return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA,
                            (EVP_PKEY_OP_SIGN | EVP_PKEY_OP_VERIFY),
                            EVP_PKEY_CTRL_RSA_PSS_SALTLEN, salt_len, NULL);
 }

 int EVP_PKEY_CTX_get_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int *out_salt_len) {
   return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA,
                            (EVP_PKEY_OP_SIGN | EVP_PKEY_OP_VERIFY),
                            EVP_PKEY_CTRL_GET_RSA_PSS_SALTLEN, 0, out_salt_len);
 }

 int EVP_PKEY_CTX_set_rsa_keygen_bits(EVP_PKEY_CTX *ctx, int bits) {
   return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_KEYGEN,
                            EVP_PKEY_CTRL_RSA_KEYGEN_BITS, bits, NULL);
 }

 int EVP_PKEY_CTX_set_rsa_keygen_pubexp(EVP_PKEY_CTX *ctx, BIGNUM *e) {
   return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_KEYGEN,
                            EVP_PKEY_CTRL_RSA_KEYGEN_PUBEXP, 0, e);
 }

 int EVP_PKEY_CTX_set_rsa_oaep_md(EVP_PKEY_CTX *ctx, const EVP_MD *md) {
   return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_TYPE_CRYPT,
                            EVP_PKEY_CTRL_RSA_OAEP_MD, 0, (void *)md);
 }

 int EVP_PKEY_CTX_get_rsa_oaep_md(EVP_PKEY_CTX *ctx, const EVP_MD **out_md) {
   return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_TYPE_CRYPT,
                            EVP_PKEY_CTRL_GET_RSA_OAEP_MD, 0, (void*) out_md);
 }

 int EVP_PKEY_CTX_set_rsa_mgf1_md(EVP_PKEY_CTX *ctx, const EVP_MD *md) {
   return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA,
                            EVP_PKEY_OP_TYPE_SIG | EVP_PKEY_OP_TYPE_CRYPT,
                            EVP_PKEY_CTRL_RSA_MGF1_MD, 0, (void*) md);
 }

 int EVP_PKEY_CTX_get_rsa_mgf1_md(EVP_PKEY_CTX *ctx, const EVP_MD **out_md) {
   return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA,
                            EVP_PKEY_OP_TYPE_SIG | EVP_PKEY_OP_TYPE_CRYPT,
                            EVP_PKEY_CTRL_GET_RSA_MGF1_MD, 0, (void*) out_md);
 }

 int EVP_PKEY_CTX_set0_rsa_oaep_label(EVP_PKEY_CTX *ctx, const uint8_t *label,
                                      size_t label_len) {
   int label_len_int = label_len;
   if (((size_t) label_len_int) != label_len) {
     return -2;
   }

   return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_TYPE_CRYPT,
                            EVP_PKEY_CTRL_RSA_OAEP_LABEL, label_len,
                            (void *)label);
 }

 int EVP_PKEY_CTX_get0_rsa_oaep_label(EVP_PKEY_CTX *ctx,
                                      const uint8_t **out_label) {
   return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_TYPE_CRYPT,
                            EVP_PKEY_CTRL_GET_RSA_OAEP_LABEL, 0, (void *) out_label);
 }
	/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
	* project 2006.
	*/
	/* ====================================================================
	* Copyright (c) 2006 The OpenSSL Project. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	*
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in
	* the documentation and/or other materials provided with the
	* distribution.
	*
	* 3. All advertising materials mentioning features or use of this
	* software must display the following acknowledgment:
	* "This product includes software developed by the OpenSSL Project
	* for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
	*
	* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
	* endorse or promote products derived from this software without
	* prior written permission. For written permission, please contact
	* licensing@OpenSSL.org.
	*
	* 5. Products derived from this software may not be called "OpenSSL"
	* nor may "OpenSSL" appear in their names without prior written
	* permission of the OpenSSL Project.
	*
	* 6. Redistributions of any form whatsoever must retain the following
	* acknowledgment:
	* "This product includes software developed by the OpenSSL Project
	* for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
	*
	* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
	* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
	* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
	* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
	* OF THE POSSIBILITY OF SUCH DAMAGE.
	* ====================================================================
	*
	* This product includes cryptographic software written by Eric Young
	* (eay@cryptsoft.com). This product includes software written by Tim
	* Hudson (tjh@cryptsoft.com). */

	#include <openssl/evp.h>

	#include <openssl/bn.h>
	#include <openssl/buf.h>
	#include <openssl/digest.h>
	#include <openssl/err.h>
	#include <openssl/mem.h>
	#include <openssl/obj.h>
	#include <openssl/rsa.h>

	#include "../rsa/internal.h"
	#include "internal.h"


	typedef struct {
	/* Key gen parameters */
	int nbits;
	BIGNUM *pub_exp;
	/* RSA padding mode */
	int pad_mode;
	/* message digest */
	const EVP_MD *md;
	/* message digest for MGF1 */
	const EVP_MD *mgf1md;
	/* PSS salt length */
	int saltlen;
	/* tbuf is a buffer which is either NULL, or is the size of the RSA modulus.
	* It's used to store the output of RSA operations. */
	uint8_t *tbuf;
	/* OAEP label */
	uint8_t *oaep_label;
	size_t oaep_labellen;
	} RSA_PKEY_CTX;

	static int pkey_rsa_init(EVP_PKEY_CTX *ctx) {
	RSA_PKEY_CTX *rctx;
	rctx = OPENSSL_malloc(sizeof(RSA_PKEY_CTX));
	if (!rctx) {
	return 0;
	}
	memset(rctx, 0, sizeof(RSA_PKEY_CTX));

	rctx->nbits = 2048;
	rctx->pad_mode = RSA_PKCS1_PADDING;
	rctx->saltlen = -2;

	ctx->data = rctx;

	return 1;
	}

	static int pkey_rsa_copy(EVP_PKEY_CTX dst, EVP_PKEY_CTX src) {
	RSA_PKEY_CTX dctx, sctx;
	if (!pkey_rsa_init(dst)) {
	return 0;
	}
	sctx = src->data;
	dctx = dst->data;
	dctx->nbits = sctx->nbits;
	if (sctx->pub_exp) {
	dctx->pub_exp = BN_dup(sctx->pub_exp);
	if (!dctx->pub_exp) {
	return 0;
	}
	}

	dctx->pad_mode = sctx->pad_mode;
	dctx->md = sctx->md;
	dctx->mgf1md = sctx->mgf1md;
	if (sctx->oaep_label) {
	if (dctx->oaep_label) {
	OPENSSL_free(dctx->oaep_label);
	}
	dctx->oaep_label = BUF_memdup(sctx->oaep_label, sctx->oaep_labellen);
	if (!dctx->oaep_label) {
	return 0;
	}
	dctx->oaep_labellen = sctx->oaep_labellen;
	}

	return 1;
	}

	static void pkey_rsa_cleanup(EVP_PKEY_CTX *ctx) {
	RSA_PKEY_CTX *rctx = ctx->data;

	if (rctx == NULL) {
	return;
	}

	if (rctx->pub_exp) {
	BN_free(rctx->pub_exp);
	}
	if (rctx->tbuf) {
	OPENSSL_free(rctx->tbuf);
	}
	if (rctx->oaep_label) {
	OPENSSL_free(rctx->oaep_label);
	}
	OPENSSL_free(rctx);
	}

	static int setup_tbuf(RSA_PKEY_CTX ctx, EVP_PKEY_CTX pk) {
	if (ctx->tbuf) {
	return 1;
	}
	ctx->tbuf = OPENSSL_malloc(EVP_PKEY_size(pk->pkey));
	if (!ctx->tbuf) {
	return 0;
	}
	return 1;
	}

	static int pkey_rsa_sign(EVP_PKEY_CTX ctx, uint8_t sig, size_t *siglen,
	const uint8_t *tbs, size_t tbslen) {
	RSA_PKEY_CTX *rctx = ctx->data;
	RSA *rsa = ctx->pkey->pkey.rsa;
	const size_t key_len = EVP_PKEY_size(ctx->pkey);

	if (!sig) {
	*siglen = key_len;
	return 1;
	}

	if (*siglen < key_len) {
	OPENSSL_PUT_ERROR(EVP, pkey_rsa_sign, EVP_R_BUFFER_TOO_SMALL);
	return 0;
	}

	if (rctx->md) {
	unsigned int out_len;

	if (tbslen != EVP_MD_size(rctx->md)) {
	OPENSSL_PUT_ERROR(EVP, pkey_rsa_sign, EVP_R_INVALID_DIGEST_LENGTH);
	return 0;
	}

	if (EVP_MD_type(rctx->md) == NID_mdc2) {
	OPENSSL_PUT_ERROR(EVP, pkey_rsa_sign, EVP_R_NO_MDC2_SUPPORT);
	return 0;
	}

	switch (rctx->pad_mode) {
	case RSA_PKCS1_PADDING:
	if (!RSA_sign(EVP_MD_type(rctx->md), tbs, tbslen, sig, &out_len, rsa)) {
	return 0;
	}
	*siglen = out_len;
	return 1;

	case RSA_PKCS1_PSS_PADDING:
	if (!setup_tbuf(rctx, ctx) \|\|
	!RSA_padding_add_PKCS1_PSS_mgf1(rsa, rctx->tbuf, tbs, rctx->md,
	rctx->mgf1md, rctx->saltlen) \|\|
	!RSA_sign_raw(rsa, siglen, sig, *siglen, rctx->tbuf, key_len,
	RSA_NO_PADDING)) {
	return 0;
	}
	return 1;

	default:
	return 0;
	}
	}

	return RSA_sign_raw(rsa, siglen, sig, *siglen, tbs, tbslen, rctx->pad_mode);
	}

	static int pkey_rsa_verify(EVP_PKEY_CTX ctx, const uint8_t sig,
	size_t siglen, const uint8_t *tbs,
	size_t tbslen) {
	RSA_PKEY_CTX *rctx = ctx->data;
	RSA *rsa = ctx->pkey->pkey.rsa;
	size_t rslen;
	const size_t key_len = EVP_PKEY_size(ctx->pkey);

	if (rctx->md) {
	switch (rctx->pad_mode) {
	case RSA_PKCS1_PADDING:
	return RSA_verify(EVP_MD_type(rctx->md), tbs, tbslen, sig, siglen, rsa);

	case RSA_PKCS1_PSS_PADDING:
	if (!setup_tbuf(rctx, ctx) \|\|
	!RSA_verify_raw(rsa, &rslen, rctx->tbuf, key_len, sig, siglen,
	RSA_NO_PADDING) \|\|
	!RSA_verify_PKCS1_PSS_mgf1(rsa, tbs, rctx->md, rctx->mgf1md,
	rctx->tbuf, rctx->saltlen)) {
	return 0;
	}
	return 1;

	default:
	return 0;
	}
	}

	if (!setup_tbuf(rctx, ctx) \|\|
	!RSA_verify_raw(rsa, &rslen, rctx->tbuf, key_len, sig, siglen,
	rctx->pad_mode) \|\|
	rslen != tbslen \|\|
	CRYPTO_memcmp(tbs, rctx->tbuf, rslen) != 0) {
	return 0;
	}

	return 1;
	}

	static int pkey_rsa_encrypt(EVP_PKEY_CTX ctx, uint8_t out, size_t *outlen,
	const uint8_t *in, size_t inlen) {
	RSA_PKEY_CTX *rctx = ctx->data;
	RSA *rsa = ctx->pkey->pkey.rsa;
	const size_t key_len = EVP_PKEY_size(ctx->pkey);

	if (!out) {
	*outlen = key_len;
	return 1;
	}

	if (*outlen < key_len) {
	OPENSSL_PUT_ERROR(EVP, pkey_rsa_encrypt, EVP_R_BUFFER_TOO_SMALL);
	return 0;
	}

	if (rctx->pad_mode == RSA_PKCS1_OAEP_PADDING) {
	if (!setup_tbuf(rctx, ctx) \|\|
	!RSA_padding_add_PKCS1_OAEP_mgf1(rctx->tbuf, key_len, in, inlen,
	rctx->oaep_label, rctx->oaep_labellen,
	rctx->md, rctx->mgf1md) \|\|
	!RSA_encrypt(rsa, outlen, out, *outlen, rctx->tbuf, key_len,
	RSA_NO_PADDING)) {
	return 0;
	}
	return 1;
	}

	return RSA_encrypt(rsa, outlen, out, *outlen, in, inlen, rctx->pad_mode);
	}

	static int pkey_rsa_decrypt(EVP_PKEY_CTX ctx, uint8_t out,
	size_t outlen, const uint8_t in,
	size_t inlen) {
	RSA_PKEY_CTX *rctx = ctx->data;
	RSA *rsa = ctx->pkey->pkey.rsa;
	const size_t key_len = EVP_PKEY_size(ctx->pkey);

	if (!out) {
	*outlen = key_len;
	return 1;
	}

	if (*outlen < key_len) {
	OPENSSL_PUT_ERROR(EVP, pkey_rsa_decrypt, EVP_R_BUFFER_TOO_SMALL);
	return 0;
	}

	if (rctx->pad_mode == RSA_PKCS1_OAEP_PADDING) {
	size_t plaintext_len;
	int message_len;

	if (!setup_tbuf(rctx, ctx) \|\|
	!RSA_decrypt(rsa, &plaintext_len, rctx->tbuf, key_len, in, inlen,
	RSA_NO_PADDING)) {
	return 0;
	}

	message_len = RSA_padding_check_PKCS1_OAEP_mgf1(
	out, key_len, rctx->tbuf, plaintext_len, rctx->oaep_label,
	rctx->oaep_labellen, rctx->md, rctx->mgf1md);
	if (message_len < 0) {
	return 0;
	}
	*outlen = message_len;
	return 1;
	}

	return RSA_decrypt(rsa, outlen, out, key_len, in, inlen, rctx->pad_mode);
	}

	static int check_padding_md(const EVP_MD *md, int padding) {
	if (!md) {
	return 1;
	}

	if (padding == RSA_NO_PADDING) {
	OPENSSL_PUT_ERROR(EVP, check_padding_md, EVP_R_INVALID_PADDING_MODE);
	return 0;
	}

	return 1;
	}

	static int is_known_padding(int padding_mode) {
	switch (padding_mode) {
	case RSA_PKCS1_PADDING:
	case RSA_NO_PADDING:
	case RSA_PKCS1_OAEP_PADDING:
	case RSA_PKCS1_PSS_PADDING:
	return 1;
	default:
	return 0;
	}
	}

	static int pkey_rsa_ctrl(EVP_PKEY_CTX ctx, int type, int p1, void p2) {
	RSA_PKEY_CTX *rctx = ctx->data;
	switch (type) {
	case EVP_PKEY_CTRL_RSA_PADDING:
	if (!is_known_padding(p1) \|\| !check_padding_md(rctx->md, p1) \|\|
	(p1 == RSA_PKCS1_PSS_PADDING &&
	0 == (ctx->operation & (EVP_PKEY_OP_SIGN \| EVP_PKEY_OP_VERIFY))) \|\|
	(p1 == RSA_PKCS1_OAEP_PADDING &&
	0 == (ctx->operation & EVP_PKEY_OP_TYPE_CRYPT))) {
	OPENSSL_PUT_ERROR(EVP, pkey_rsa_ctrl,
	EVP_R_ILLEGAL_OR_UNSUPPORTED_PADDING_MODE);
	return -2;
	}
	if ((p1 == RSA_PKCS1_PSS_PADDING \|\| p1 == RSA_PKCS1_OAEP_PADDING) &&
	rctx->md == NULL) {
	rctx->md = EVP_sha1();
	}
	rctx->pad_mode = p1;
	return 1;

	case EVP_PKEY_CTRL_GET_RSA_PADDING:
	(int )p2 = rctx->pad_mode;
	return 1;

	case EVP_PKEY_CTRL_RSA_PSS_SALTLEN:
	case EVP_PKEY_CTRL_GET_RSA_PSS_SALTLEN:
	if (rctx->pad_mode != RSA_PKCS1_PSS_PADDING) {
	OPENSSL_PUT_ERROR(EVP, pkey_rsa_ctrl, EVP_R_INVALID_PSS_SALTLEN);
	return -2;
	}
	if (type == EVP_PKEY_CTRL_GET_RSA_PSS_SALTLEN) {
	(int )p2 = rctx->saltlen;
	} else {
	if (p1 < -2) {
	return -2;
	}
	rctx->saltlen = p1;
	}
	return 1;

	case EVP_PKEY_CTRL_RSA_KEYGEN_BITS:
	if (p1 < 256) {
	OPENSSL_PUT_ERROR(EVP, pkey_rsa_ctrl, EVP_R_INVALID_KEYBITS);
	return -2;
	}
	rctx->nbits = p1;
	return 1;

	case EVP_PKEY_CTRL_RSA_KEYGEN_PUBEXP:
	if (!p2) {
	return -2;
	}
	BN_free(rctx->pub_exp);
	rctx->pub_exp = p2;
	return 1;

	case EVP_PKEY_CTRL_RSA_OAEP_MD:
	case EVP_PKEY_CTRL_GET_RSA_OAEP_MD:
	if (rctx->pad_mode != RSA_PKCS1_OAEP_PADDING) {
	OPENSSL_PUT_ERROR(EVP, pkey_rsa_ctrl, EVP_R_INVALID_PADDING_MODE);
	return -2;
	}
	if (type == EVP_PKEY_CTRL_GET_RSA_OAEP_MD) {
	(const EVP_MD *)p2 = rctx->md;
	} else {
	rctx->md = p2;
	}
	return 1;

	case EVP_PKEY_CTRL_MD:
	if (!check_padding_md(p2, rctx->pad_mode)) {
	return 0;
	}
	rctx->md = p2;
	return 1;

	case EVP_PKEY_CTRL_GET_MD:
	(const EVP_MD *)p2 = rctx->md;
	return 1;

	case EVP_PKEY_CTRL_RSA_MGF1_MD:
	case EVP_PKEY_CTRL_GET_RSA_MGF1_MD:
	if (rctx->pad_mode != RSA_PKCS1_PSS_PADDING &&
	rctx->pad_mode != RSA_PKCS1_OAEP_PADDING) {
	OPENSSL_PUT_ERROR(EVP, pkey_rsa_ctrl, EVP_R_INVALID_MGF1_MD);
	return -2;
	}
	if (type == EVP_PKEY_CTRL_GET_RSA_MGF1_MD) {
	if (rctx->mgf1md) {
	(const EVP_MD *)p2 = rctx->mgf1md;
	} else {
	(const EVP_MD *)p2 = rctx->md;
	}
	} else {
	rctx->mgf1md = p2;
	}
	return 1;

	case EVP_PKEY_CTRL_RSA_OAEP_LABEL:
	if (rctx->pad_mode != RSA_PKCS1_OAEP_PADDING) {
	OPENSSL_PUT_ERROR(EVP, pkey_rsa_ctrl, EVP_R_INVALID_PADDING_MODE);
	return -2;
	}
	if (rctx->oaep_label) {
	OPENSSL_free(rctx->oaep_label);
	}
	if (p2 && p1 > 0) {
	/* TODO(fork): this seems wrong. Shouldn't it take a copy of the
	* buffer? */
	rctx->oaep_label = p2;
	rctx->oaep_labellen = p1;
	} else {
	rctx->oaep_label = NULL;
	rctx->oaep_labellen = 0;
	}
	return 1;

	case EVP_PKEY_CTRL_GET_RSA_OAEP_LABEL:
	if (rctx->pad_mode != RSA_PKCS1_OAEP_PADDING) {
	OPENSSL_PUT_ERROR(EVP, pkey_rsa_ctrl, EVP_R_INVALID_PADDING_MODE);
	return -2;
	}
	(uint8_t *)p2 = rctx->oaep_label;
	return rctx->oaep_labellen;

	case EVP_PKEY_CTRL_DIGESTINIT:
	return 1;

	default:
	return -2;
	}
	}

	static int pkey_rsa_keygen(EVP_PKEY_CTX ctx, EVP_PKEY pkey) {
	RSA *rsa = NULL;
	RSA_PKEY_CTX *rctx = ctx->data;

	if (!rctx->pub_exp) {
	rctx->pub_exp = BN_new();
	if (!rctx->pub_exp \|\| !BN_set_word(rctx->pub_exp, RSA_F4))
	return 0;
	}
	rsa = RSA_new();
	if (!rsa) {
	return 0;
	}

	if (!RSA_generate_key_ex(rsa, rctx->nbits, rctx->pub_exp, NULL)) {
	RSA_free(rsa);
	return 0;
	}

	EVP_PKEY_assign_RSA(pkey, rsa);
	return 1;
	}

	const EVP_PKEY_METHOD rsa_pkey_meth = {
	EVP_PKEY_RSA, 0 /* flags */, pkey_rsa_init,
	pkey_rsa_copy, pkey_rsa_cleanup, 0 /* paramgen_init */,
	0 /* paramgen /, 0 / keygen_init */, pkey_rsa_keygen,
	0 /* sign_init /, pkey_rsa_sign, 0 / verify_init */,
	pkey_rsa_verify, 0 /* signctx_init /, 0 / signctx */,
	0 /* verifyctx_init /, 0 / verifyctx /, 0 / encrypt_init */,
	pkey_rsa_encrypt, 0 /* decrypt_init */, pkey_rsa_decrypt,
	0 /* derive_init /, 0 / derive */, pkey_rsa_ctrl,
	};

	int EVP_PKEY_CTX_set_rsa_padding(EVP_PKEY_CTX *ctx, int padding) {
	return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, -1, EVP_PKEY_CTRL_RSA_PADDING,
	padding, NULL);
	}

	int EVP_PKEY_CTX_get_rsa_padding(EVP_PKEY_CTX ctx, int out_padding) {
	return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, -1, EVP_PKEY_CTRL_GET_RSA_PADDING,
	0, out_padding);
	}

	int EVP_PKEY_CTX_set_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int salt_len) {
	return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA,
	(EVP_PKEY_OP_SIGN \| EVP_PKEY_OP_VERIFY),
	EVP_PKEY_CTRL_RSA_PSS_SALTLEN, salt_len, NULL);
	}

	int EVP_PKEY_CTX_get_rsa_pss_saltlen(EVP_PKEY_CTX ctx, int out_salt_len) {
	return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA,
	(EVP_PKEY_OP_SIGN \| EVP_PKEY_OP_VERIFY),
	EVP_PKEY_CTRL_GET_RSA_PSS_SALTLEN, 0, out_salt_len);
	}

	int EVP_PKEY_CTX_set_rsa_keygen_bits(EVP_PKEY_CTX *ctx, int bits) {
	return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_KEYGEN,
	EVP_PKEY_CTRL_RSA_KEYGEN_BITS, bits, NULL);
	}

	int EVP_PKEY_CTX_set_rsa_keygen_pubexp(EVP_PKEY_CTX ctx, BIGNUM e) {
	return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_KEYGEN,
	EVP_PKEY_CTRL_RSA_KEYGEN_PUBEXP, 0, e);
	}

	int EVP_PKEY_CTX_set_rsa_oaep_md(EVP_PKEY_CTX ctx, const EVP_MD md) {
	return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_TYPE_CRYPT,
	EVP_PKEY_CTRL_RSA_OAEP_MD, 0, (void *)md);
	}

	int EVP_PKEY_CTX_get_rsa_oaep_md(EVP_PKEY_CTX ctx, const EVP_MD *out_md) {
	return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_TYPE_CRYPT,
	EVP_PKEY_CTRL_GET_RSA_OAEP_MD, 0, (void*) out_md);
	}

	int EVP_PKEY_CTX_set_rsa_mgf1_md(EVP_PKEY_CTX ctx, const EVP_MD md) {
	return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA,
	EVP_PKEY_OP_TYPE_SIG \| EVP_PKEY_OP_TYPE_CRYPT,
	EVP_PKEY_CTRL_RSA_MGF1_MD, 0, (void*) md);
	}

	int EVP_PKEY_CTX_get_rsa_mgf1_md(EVP_PKEY_CTX ctx, const EVP_MD *out_md) {
	return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA,
	EVP_PKEY_OP_TYPE_SIG \| EVP_PKEY_OP_TYPE_CRYPT,
	EVP_PKEY_CTRL_GET_RSA_MGF1_MD, 0, (void*) out_md);
	}

	int EVP_PKEY_CTX_set0_rsa_oaep_label(EVP_PKEY_CTX ctx, const uint8_t label,
	size_t label_len) {
	int label_len_int = label_len;
	if (((size_t) label_len_int) != label_len) {
	return -2;
	}

	return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_TYPE_CRYPT,
	EVP_PKEY_CTRL_RSA_OAEP_LABEL, label_len,
	(void *)label);
	}

	int EVP_PKEY_CTX_get0_rsa_oaep_label(EVP_PKEY_CTX *ctx,
	const uint8_t **out_label) {
	return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_RSA, EVP_PKEY_OP_TYPE_CRYPT,
	EVP_PKEY_CTRL_GET_RSA_OAEP_LABEL, 0, (void *) out_label);
	}