/* fips/rand/fips_rand_lcl.h */
/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
 * project.
 */
/* ====================================================================
 * Copyright (c) 2011 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.
 * ====================================================================
 */

typedef struct drbg_hash_ctx_st DRBG_HASH_CTX;
typedef struct drbg_hmac_ctx_st DRBG_HMAC_CTX;
typedef struct drbg_ctr_ctx_st DRBG_CTR_CTX;

/* 888 bits from 10.1 table 2 */
#define HASH_PRNG_MAX_SEEDLEN   111

struct drbg_hash_ctx_st {
    const EVP_MD *md;
    EVP_MD_CTX *mctx;
    unsigned char V[HASH_PRNG_MAX_SEEDLEN];
    unsigned char C[HASH_PRNG_MAX_SEEDLEN];
    /* Temporary value storage: should always exceed max digest length */
    unsigned char vtmp[HASH_PRNG_MAX_SEEDLEN];
};

struct drbg_hmac_ctx_st {
    const EVP_MD *md;
    HMAC_CTX *hctx;
    unsigned char K[EVP_MAX_MD_SIZE];
    unsigned char V[EVP_MAX_MD_SIZE];
};

struct drbg_ctr_ctx_st {
    AES_KEY ks;
    size_t keylen;
    unsigned char K[32];
    unsigned char V[16];
    /* Temp variables used by derivation function */
    AES_KEY df_ks;
    AES_KEY df_kxks;
    /* Temporary block storage used by ctr_df */
    unsigned char bltmp[16];
    size_t bltmp_pos;
    unsigned char KX[48];
};

/* DRBG internal flags */

/* Functions shouldn't call err library */
#define DRBG_FLAG_NOERR                 0x1
/* Custom reseed checking */
#define DRBG_CUSTOM_RESEED              0x2

/* DRBG status values */
/* not initialised */
#define DRBG_STATUS_UNINITIALISED       0
/* ok and ready to generate random bits */
#define DRBG_STATUS_READY               1
/* reseed required */
#define DRBG_STATUS_RESEED              2
/* fatal error condition */
#define DRBG_STATUS_ERROR               3

/* A default maximum length: larger than any reasonable value used in pratice */

#define DRBG_MAX_LENGTH                 0x7ffffff0
/* Maximum DRBG block length: all md sizes are bigger than cipher blocks sizes
 * so use max digest length.
 */
#define DRBG_MAX_BLOCK                  EVP_MAX_MD_SIZE

#define DRBG_HEALTH_INTERVAL            (1 << 24)

/* DRBG context structure */

struct drbg_ctx_st {
    /* First types common to all implementations */
    /* DRBG type: a NID for the underlying algorithm */
    int type;
    /* Various external flags */
    unsigned int xflags;
    /* Various internal use only flags */
    unsigned int iflags;
    /* Used for periodic health checks */
    int health_check_cnt, health_check_interval;

    /* The following parameters are setup by mechanism drbg_init() call */
    int strength;
    size_t blocklength;
    size_t max_request;

    size_t min_entropy, max_entropy;
    size_t min_nonce, max_nonce;
    size_t max_pers, max_adin;
    unsigned int reseed_counter;
    unsigned int reseed_interval;
    size_t seedlen;
    int status;
    /* Application data: typically used by test get_entropy */
    void *app_data;
    /* Implementation specific structures */
    union {
        DRBG_HASH_CTX hash;
        DRBG_HMAC_CTX hmac;
        DRBG_CTR_CTX ctr;
    } d;
    /* Initialiase PRNG and setup callbacks below */
    int (*init) (DRBG_CTX *ctx, int nid, int security, unsigned int flags);
    /* Intantiate PRNG */
    int (*instantiate) (DRBG_CTX *ctx,
                        const unsigned char *ent, size_t entlen,
                        const unsigned char *nonce, size_t noncelen,
                        const unsigned char *pers, size_t perslen);
    /* reseed */
    int (*reseed) (DRBG_CTX *ctx,
                   const unsigned char *ent, size_t entlen,
                   const unsigned char *adin, size_t adinlen);
    /* generat output */
    int (*generate) (DRBG_CTX *ctx,
                     unsigned char *out, size_t outlen,
                     const unsigned char *adin, size_t adinlen);
    /* uninstantiate */
    int (*uninstantiate) (DRBG_CTX *ctx);

    /* Entropy source block length */
    size_t entropy_blocklen;

    /* entropy gathering function */
    size_t (*get_entropy) (DRBG_CTX *ctx, unsigned char **pout,
                           int entropy, size_t min_len, size_t max_len);
    /* Indicates we have finished with entropy buffer */
    void (*cleanup_entropy) (DRBG_CTX *ctx, unsigned char *out, size_t olen);

    /* nonce gathering function */
    size_t (*get_nonce) (DRBG_CTX *ctx, unsigned char **pout,
                         int entropy, size_t min_len, size_t max_len);
    /* Indicates we have finished with nonce buffer */
    void (*cleanup_nonce) (DRBG_CTX *ctx, unsigned char *out, size_t olen);

    /* Callbacks used when called through RAND interface */
    /* Get any additional input for generate */
    size_t (*get_adin) (DRBG_CTX *ctx, unsigned char **pout);
    void (*cleanup_adin) (DRBG_CTX *ctx, unsigned char *out, size_t olen);
    /* Callback for RAND_seed(), RAND_add() */
    int (*rand_seed_cb) (DRBG_CTX *ctx, const void *buf, int num);
    int (*rand_add_cb) (DRBG_CTX *ctx,
                        const void *buf, int num, double entropy);
};

int fips_drbg_ctr_init(DRBG_CTX *dctx);
int fips_drbg_hash_init(DRBG_CTX *dctx);
int fips_drbg_hmac_init(DRBG_CTX *dctx);
int fips_drbg_kat(DRBG_CTX *dctx, int nid, unsigned int flags);
int fips_drbg_cprng_test(DRBG_CTX *dctx, const unsigned char *out);

#define FIPS_digestinit EVP_DigestInit
#define FIPS_digestupdate EVP_DigestUpdate
#define FIPS_digestfinal EVP_DigestFinal
#define M_EVP_MD_size EVP_MD_size