text: /*
   * Copyright 2006-2017 The OpenSSL Project Authors. All Rights Reserved.
   *
   * Licensed under the Apache License 2.0 (the "License").  You may not use
   * this file except in compliance with the License.  You can obtain a copy
   * in the file LICENSE in the source distribution or at
   * https://www.openssl.org/source/license.html
   */
  
  #include <openssl/rsa.h>
  #include "internal/refcount.h"
  
  #define RSA_MAX_PRIME_NUM       5
  #define RSA_MIN_MODULUS_BITS    512
  
  typedef struct rsa_prime_info_st {
      BIGNUM *r;
      BIGNUM *d;
      BIGNUM *t;
      /* save product of primes prior to this one */
      BIGNUM *pp;
      BN_MONT_CTX *m;
  } RSA_PRIME_INFO;
  
  DECLARE_ASN1_ITEM(RSA_PRIME_INFO)
  DEFINE_STACK_OF(RSA_PRIME_INFO)
  
  struct rsa_st {
      /*
       * The first parameter is used to pickup errors where this is passed
       * instead of an EVP_PKEY, it is set to 0
       */
      int pad;
      int32_t version;
      const RSA_METHOD *meth;
      /* functional reference if 'meth' is ENGINE-provided */
      ENGINE *engine;
      BIGNUM *n;
      BIGNUM *e;
      BIGNUM *d;
      BIGNUM *p;
      BIGNUM *q;
      BIGNUM *dmp1;
      BIGNUM *dmq1;
      BIGNUM *iqmp;
      /* for multi-prime RSA, defined in RFC 8017 */
      STACK_OF(RSA_PRIME_INFO) *prime_infos;
      /* If a PSS only key this contains the parameter restrictions */
      RSA_PSS_PARAMS *pss;
      /* be careful using this if the RSA structure is shared */
      CRYPTO_EX_DATA ex_data;
      CRYPTO_REF_COUNT references;
      int flags;
      /* Used to cache montgomery values */
      BN_MONT_CTX *_method_mod_n;
      BN_MONT_CTX *_method_mod_p;
      BN_MONT_CTX *_method_mod_q;
      /*
       * all BIGNUM values are actually in the following data, if it is not
       * NULL
       */
      char *bignum_data;
      BN_BLINDING *blinding;
      BN_BLINDING *mt_blinding;
      CRYPTO_RWLOCK *lock;
  };
  
  struct rsa_meth_st {
      char *name;
      int (*rsa_pub_enc) (int flen, const unsigned char *from,
                          unsigned char *to, RSA *rsa, int padding);
      int (*rsa_pub_dec) (int flen, const unsigned char *from,
                          unsigned char *to, RSA *rsa, int padding);
      int (*rsa_priv_enc) (int flen, const unsigned char *from,
                           unsigned char *to, RSA *rsa, int padding);
      int (*rsa_priv_dec) (int flen, const unsigned char *from,
                           unsigned char *to, RSA *rsa, int padding);
      /* Can be null */
      int (*rsa_mod_exp) (BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx);
      /* Can be null */
      int (*bn_mod_exp) (BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                         const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
      /* called at new */
      int (*init) (RSA *rsa);
      /* called at free */
      int (*finish) (RSA *rsa);
      /* RSA_METHOD_FLAG_* things */
      int flags;
      /* may be needed! */
      char *app_data;
      /*
       * New sign and verify functions: some libraries don't allow arbitrary
       * data to be signed/verified: this allows them to be used. Note: for
       * this to work the RSA_public_decrypt() and RSA_private_encrypt() should
       * *NOT* be used RSA_sign(), RSA_verify() should be used instead.
       */
      int (*rsa_sign) (int type,
                       const unsigned char *m, unsigned int m_length,
                       unsigned char *sigret, unsigned int *siglen,
                       const RSA *rsa);
      int (*rsa_verify) (int dtype, const unsigned char *m,
                         unsigned int m_length, const unsigned char *sigbuf,
                         unsigned int siglen, const RSA *rsa);
      /*
       * If this callback is NULL, the builtin software RSA key-gen will be
       * used. This is for behavioural compatibility whilst the code gets
       * rewired, but one day it would be nice to assume there are no such
       * things as "builtin software" implementations.
       */
      int (*rsa_keygen) (RSA *rsa, int bits, BIGNUM *e, BN_GENCB *cb);
      int (*rsa_multi_prime_keygen) (RSA *rsa, int bits, int primes,
                                     BIGNUM *e, BN_GENCB *cb);
  };
  
  extern int int_rsa_verify(int dtype, const unsigned char *m,
                            unsigned int m_len, unsigned char *rm,
                            size_t *prm_len, const unsigned char *sigbuf,
                            size_t siglen, RSA *rsa);
  /* Macros to test if a pkey or ctx is for a PSS key */
  #define pkey_is_pss(pkey) (pkey->ameth->pkey_id == EVP_PKEY_RSA_PSS)
  #define pkey_ctx_is_pss(ctx) (ctx->pmeth->pkey_id == EVP_PKEY_RSA_PSS)
  
  RSA_PSS_PARAMS *rsa_pss_params_create(const EVP_MD *sigmd,
                                        const EVP_MD *mgf1md, int saltlen);
  int rsa_pss_get_param(const RSA_PSS_PARAMS *pss, const EVP_MD **pmd,
                        const EVP_MD **pmgf1md, int *psaltlen);
  /* internal function to clear and free multi-prime parameters */
  void rsa_multip_info_free_ex(RSA_PRIME_INFO *pinfo);
  void rsa_multip_info_free(RSA_PRIME_INFO *pinfo);
  RSA_PRIME_INFO *rsa_multip_info_new(void);
  int rsa_multip_calc_product(RSA *rsa);
  int rsa_multip_cap(int bits);
  