Commit 12fb8c3d authored by Rich Salz's avatar Rich Salz
Browse files

Add DRBG random method 



Ported from the last FIPS release, with DUAL_EC and SHA1 and the
self-tests removed.  Since only AES-CTR is supported, other code
simplifications were done.  Removed the "entropy blocklen" concept.

Moved internal functions to new include/internal/rand.h.

Reviewed-by: default avatarPaul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/3789)
parent 0299f3f7

crypto/err/openssl.txt

+30 −5
Original line number Diff line number Diff line
@@ -860,9 +860,17 @@ PKCS7_F_PKCS7_SIGNER_INFO_SIGN:139:PKCS7_SIGNER_INFO_sign 
PKCS7_F_PKCS7_SIGN_ADD_SIGNER:137:PKCS7_sign_add_signer

PKCS7_F_PKCS7_SIMPLE_SMIMECAP:119:PKCS7_simple_smimecap

PKCS7_F_PKCS7_VERIFY:117:PKCS7_verify

RAND_F_DRBG_BYTES:101:drbg_bytes

RAND_F_DRBG_GET_ENTROPY:105:drbg_get_entropy

RAND_F_GET_ENTROPY:106:get_entropy

RAND_F_RAND_BYTES:100:RAND_bytes

RAND_F_RAND_LOAD_FILE:101:RAND_load_file

RAND_F_RAND_WRITE_FILE:102:RAND_write_file

RAND_F_RAND_DRBG_GENERATE:107:RAND_DRBG_generate

RAND_F_RAND_DRBG_INSTANTIATE:108:RAND_DRBG_instantiate

RAND_F_RAND_DRBG_NEW:109:RAND_DRBG_new

RAND_F_RAND_DRBG_RESEED:110:RAND_DRBG_reseed

RAND_F_RAND_DRBG_SET:104:RAND_DRBG_set

RAND_F_RAND_LOAD_FILE:111:RAND_load_file

RAND_F_RAND_WRITE_FILE:112:RAND_write_file

RSA_F_CHECK_PADDING_MD:140:check_padding_md

RSA_F_ENCODE_PKCS1:146:encode_pkcs1

RSA_F_INT_RSA_VERIFY:145:int_rsa_verify
@@ -2098,11 +2106,28 @@ PKCS7_R_UNSUPPORTED_CIPHER_TYPE:111:unsupported cipher type 
PKCS7_R_UNSUPPORTED_CONTENT_TYPE:112:unsupported content type

PKCS7_R_WRONG_CONTENT_TYPE:113:wrong content type

PKCS7_R_WRONG_PKCS7_TYPE:114:wrong pkcs7 type

RAND_R_CANNOT_OPEN_FILE:102:Cannot open file

RAND_R_ADDITIONAL_INPUT_TOO_LONG:102:additional input too long

RAND_R_ALREADY_INSTANTIATED:103:already instantiated

RAND_R_CANNOT_OPEN_FILE:121:Cannot open file

RAND_R_DRBG_NOT_INITIALISED:104:drbg not initialised

RAND_R_ERROR_INITIALISING_DRBG:107:error initialising drbg

RAND_R_ERROR_INSTANTIATING_DRBG:108:error instantiating drbg

RAND_R_ERROR_RETRIEVING_ADDITIONAL_INPUT:109:error retrieving additional input

RAND_R_ERROR_RETRIEVING_ENTROPY:110:error retrieving entropy

RAND_R_ERROR_RETRIEVING_NONCE:111:error retrieving nonce

RAND_R_FUNC_NOT_IMPLEMENTED:101:Function not implemented

RAND_R_FWRITE_ERROR:103:Error writing file

RAND_R_NOT_A_REGULAR_FILE:104:Not a regular file

RAND_R_FWRITE_ERROR:123:Error writing file

RAND_R_GENERATE_ERROR:112:generate error

RAND_R_INTERNAL_ERROR:113:internal error

RAND_R_IN_ERROR_STATE:114:in error state

RAND_R_NOT_A_REGULAR_FILE:122:Not a regular file

RAND_R_NOT_INSTANTIATED:115:not instantiated

RAND_R_PERSONALISATION_STRING_TOO_LONG:116:personalisation string too long

RAND_R_PRNG_NOT_SEEDED:100:PRNG not seeded

RAND_R_REQUEST_TOO_LARGE_FOR_DRBG:117:request too large for drbg

RAND_R_RESEED_ERROR:118:reseed error

RAND_R_SELFTEST_FAILURE:119:selftest failure

RAND_R_UNSUPPORTED_DRBG_TYPE:120:unsupported drbg type

RSA_R_ALGORITHM_MISMATCH:100:algorithm mismatch

RSA_R_BAD_E_VALUE:101:bad e value

RSA_R_BAD_FIXED_HEADER_DECRYPT:102:bad fixed header decrypt

crypto/rand/build.info

+1 −1
Original line number Diff line number Diff line 
LIBS=../../libcrypto

SOURCE[../../libcrypto]=\

        ossl_rand.c randfile.c rand_lib.c rand_err.c rand_egd.c \

        rand_win.c rand_unix.c rand_vms.c
 
        rand_win.c rand_unix.c rand_vms.c drbg_lib.c drbg_rand.c

crypto/rand/drbg_lib.c

0 → 100644
+349 −0
Original line number Diff line number Diff line 
/*

 * Copyright 2011-2017 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (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 <string.h>

#include <openssl/crypto.h>

#include <openssl/err.h>

#include <openssl/rand.h>

#include "rand_lcl.h"



/*

 * Support framework for NIST SP 800-90A DRBG, AES-CTR mode.

 */



/*

 * Get entropy from the existing callback.  This is mainly used for KATs.

 */

static size_t get_entropy(DRBG_CTX *dctx, unsigned char **pout,

                          int entropy, size_t min_len, size_t max_len)

{

    if (dctx->get_entropy != NULL)

        return dctx->get_entropy(dctx, pout, entropy, min_len, max_len);

    /* TODO: Get from parent if it exists. */

    return 0;

}



/*

 * Cleanup entropy.

 */

static void cleanup_entropy(DRBG_CTX *dctx, unsigned char *out, size_t olen)

{

    if (dctx->cleanup_entropy != NULL)

        dctx->cleanup_entropy(dctx, out, olen);

}



/*

 * The OpenSSL model is to have new and free functions, and that new

 * does all initialization.  That is not the NIST model, which has

 * instantiation and un-instantiate, and re-use within a new/free

 * lifecycle.  (No doubt this comes from the desire to support hardware

 * DRBG, where allocation of resources on something like an HSM is

 * a much bigger deal than just re-setting an allocated resource.)

 *

 * The DRBG_CTX is OpenSSL's opaque pointer to an instance of the

 * DRBG.

 */



/*

 * Set/initialize |dctx| to be of type |nid|, with optional |flags|.

 * Return -2 if the type is not supported, 1 on success and -1 on

 * failure.

 */

int RAND_DRBG_set(DRBG_CTX *dctx, int nid, unsigned int flags)

{

    int ret = 1;



    dctx->status = DRBG_STATUS_UNINITIALISED;

    dctx->flags = flags;

    dctx->nid = nid;



    switch (nid) {

    default:

        RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);

        return -2;

    case 0:

        /* Uninitialized; that's okay. */

        return 1;

    case NID_aes_128_ctr:

    case NID_aes_192_ctr:

    case NID_aes_256_ctr:

        ret = ctr_init(dctx);

        break;

    }



    if (ret < 0)

        RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG);

    return ret;

}



/*

 * Allocate memory and initialize a new DRBG.  The |parent|, if not

 * NULL, will be used to auto-seed this DRBG_CTX as needed.

 */

DRBG_CTX *RAND_DRBG_new(int type, unsigned int flags, DRBG_CTX *parent)

{

    DRBG_CTX *dctx = OPENSSL_zalloc(sizeof(*dctx));



    if (dctx == NULL) {

        RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE);

        return NULL;

    }



    dctx->parent = parent;

    if (RAND_DRBG_set(dctx, type, flags) < 0) {

        OPENSSL_free(dctx);

        return NULL;

    }

    return dctx;

}



/*

 * Uninstantiate |dctx| and free all memory.

 */

void RAND_DRBG_free(DRBG_CTX *dctx)

{

    if (dctx == NULL)

        return;



    ctr_uninstantiate(dctx);

    CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, dctx, &dctx->ex_data);



    /* Don't free up default DRBG */

    if (dctx == RAND_DRBG_get_default()) {

        memset(dctx, 0, sizeof(DRBG_CTX));

        dctx->nid = 0;

        dctx->status = DRBG_STATUS_UNINITIALISED;

    } else {

        OPENSSL_cleanse(&dctx->ctr, sizeof(dctx->ctr));

        OPENSSL_free(dctx);

    }

}



/*

 * Instantiate |dctx|, after it has been initialized.  Use |pers| and

 * |perslen| as prediction-resistance input.

 */

int RAND_DRBG_instantiate(DRBG_CTX *dctx,

                          const unsigned char *pers, size_t perslen)

{

    size_t entlen = 0, noncelen = 0;

    unsigned char *nonce = NULL, *entropy = NULL;

    int r = 0;



    if (perslen > dctx->max_pers) {

        r = RAND_R_PERSONALISATION_STRING_TOO_LONG;

        goto end;

    }

    if (dctx->status != DRBG_STATUS_UNINITIALISED) {

        r = dctx->status == DRBG_STATUS_ERROR ? RAND_R_IN_ERROR_STATE

                                              : RAND_R_ALREADY_INSTANTIATED;

        goto end;

    }



    dctx->status = DRBG_STATUS_ERROR;

    entlen = get_entropy(dctx, &entropy, dctx->strength,

                         dctx->min_entropy, dctx->max_entropy);

    if (entlen < dctx->min_entropy || entlen > dctx->max_entropy) {

        r = RAND_R_ERROR_RETRIEVING_ENTROPY;

        goto end;

    }



    if (dctx->max_nonce > 0 && dctx->get_nonce != NULL) {

        noncelen = dctx->get_nonce(dctx, &nonce,

                                   dctx->strength / 2,

                                   dctx->min_nonce, dctx->max_nonce);



        if (noncelen < dctx->min_nonce || noncelen > dctx->max_nonce) {

            r = RAND_R_ERROR_RETRIEVING_NONCE;

            goto end;

        }

    }



    if (!ctr_instantiate(dctx, entropy, entlen,

                         nonce, noncelen, pers, perslen)) {

        r = RAND_R_ERROR_INSTANTIATING_DRBG;

        goto end;

    }



    dctx->status = DRBG_STATUS_READY;

    dctx->reseed_counter = 1;



end:

    if (entropy != NULL && dctx->cleanup_entropy != NULL)

        dctx->cleanup_entropy(dctx, entropy, entlen);

    if (nonce != NULL && dctx->cleanup_nonce!= NULL )

        dctx->cleanup_nonce(dctx, nonce, noncelen);

    if (dctx->status == DRBG_STATUS_READY)

        return 1;



    if (r)

        RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, r);

    return 0;

}



/*

 * Uninstantiate |dctx|. Must be instantiated before it can be used.

 */

int RAND_DRBG_uninstantiate(DRBG_CTX *dctx)

{

    int ret = ctr_uninstantiate(dctx);



    OPENSSL_cleanse(&dctx->ctr, sizeof(dctx->ctr));

    dctx->status = DRBG_STATUS_UNINITIALISED;

    return ret;

}



/*

 * Mix in the specified data to reseed |dctx|.

 */

int RAND_DRBG_reseed(DRBG_CTX *dctx,

                     const unsigned char *adin, size_t adinlen)

{

    unsigned char *entropy = NULL;

    size_t entlen = 0;

    int r = 0;



    if (dctx->status != DRBG_STATUS_READY

            && dctx->status != DRBG_STATUS_RESEED) {

        if (dctx->status == DRBG_STATUS_ERROR)

            r = RAND_R_IN_ERROR_STATE;

        else if (dctx->status == DRBG_STATUS_UNINITIALISED)

            r = RAND_R_NOT_INSTANTIATED;

        goto end;

    }



    if (adin == NULL)

        adinlen = 0;

    else if (adinlen > dctx->max_adin) {

        r = RAND_R_ADDITIONAL_INPUT_TOO_LONG;

        goto end;

    }



    dctx->status = DRBG_STATUS_ERROR;

    entlen = get_entropy(dctx, &entropy, dctx->strength,

                         dctx->min_entropy, dctx->max_entropy);



    if (entlen < dctx->min_entropy || entlen > dctx->max_entropy) {

        r = RAND_R_ERROR_RETRIEVING_ENTROPY;

        goto end;

    }



    if (!ctr_reseed(dctx, entropy, entlen, adin, adinlen))

        goto end;

    dctx->status = DRBG_STATUS_READY;

    dctx->reseed_counter = 1;



end:

    if (entropy != NULL && dctx->cleanup_entropy != NULL)

        cleanup_entropy(dctx, entropy, entlen);

    if (dctx->status == DRBG_STATUS_READY)

        return 1;

    if (r)

        RANDerr(RAND_F_RAND_DRBG_RESEED, r);



    return 0;

}



/*

 * Generate |outlen| bytes into the buffer at |out|.  Reseed if we need

 * to or if |prediction_resistance| is set.  Additional input can be

 * sent in |adin| and |adinlen|.

 */

int RAND_DRBG_generate(DRBG_CTX *dctx, unsigned char *out, size_t outlen,

                       int prediction_resistance,

                       const unsigned char *adin, size_t adinlen)

{

    int r = 0;



    if (dctx->status != DRBG_STATUS_READY

            && dctx->status != DRBG_STATUS_RESEED) {

        if (dctx->status == DRBG_STATUS_ERROR)

            r = RAND_R_IN_ERROR_STATE;

        else if(dctx->status == DRBG_STATUS_UNINITIALISED)

            r = RAND_R_NOT_INSTANTIATED;

        goto end;

    }



    if (outlen > dctx->max_request) {

        r = RAND_R_REQUEST_TOO_LARGE_FOR_DRBG;

        return 0;

    }

    if (adinlen > dctx->max_adin) {

        r = RAND_R_ADDITIONAL_INPUT_TOO_LONG;

        goto end;

    }



    if (dctx->reseed_counter >= dctx->reseed_interval)

        dctx->status = DRBG_STATUS_RESEED;



    if (dctx->status == DRBG_STATUS_RESEED || prediction_resistance) {

        if (!RAND_DRBG_reseed(dctx, adin, adinlen)) {

            r = RAND_R_RESEED_ERROR;

            goto end;

        }

        adin = NULL;

        adinlen = 0;

    }



    if (!ctr_generate(dctx, out, outlen, adin, adinlen)) {

        r = RAND_R_GENERATE_ERROR;

        dctx->status = DRBG_STATUS_ERROR;

        goto end;

    }

    if (dctx->reseed_counter >= dctx->reseed_interval)

        dctx->status = DRBG_STATUS_RESEED;

    else

        dctx->reseed_counter++;

    return 1;



end:

    RANDerr(RAND_F_RAND_DRBG_GENERATE, r);

    return 0;

}



/*

 * Set the callbacks for entropy and nonce.  Used mainly for the KATs

 */

int RAND_DRBG_set_callbacks(DRBG_CTX *dctx,

    size_t (*cb_get_entropy)(DRBG_CTX *ctx, unsigned char **pout,

                             int entropy, size_t min_len, size_t max_len),

    void (*cb_cleanup_entropy)(DRBG_CTX *ctx, unsigned char *out, size_t olen),

    size_t (*cb_get_nonce)(DRBG_CTX *ctx, unsigned char **pout,

                           int entropy, size_t min_len, size_t max_len),

    void (*cb_cleanup_nonce)(DRBG_CTX *ctx, unsigned char *out, size_t olen))

{

    if (dctx->status != DRBG_STATUS_UNINITIALISED)

        return 0;

    dctx->get_entropy = cb_get_entropy;

    dctx->cleanup_entropy = cb_cleanup_entropy;

    dctx->get_nonce = cb_get_nonce;

    dctx->cleanup_nonce = cb_cleanup_nonce;

    return 1;

}



/*

 * Set the reseed internal. Used mainly for the KATs.

 */

void RAND_DRBG_set_reseed_interval(DRBG_CTX *dctx, int interval)

{

    dctx->reseed_interval = interval;

}



/*

 * Get and set the EXDATA

 */

int RAND_DRBG_set_ex_data(DRBG_CTX *dctx, int idx, void *arg)

{

    return CRYPTO_set_ex_data(&dctx->ex_data, idx, arg);

}



void *RAND_DRBG_get_ex_data(const DRBG_CTX *dctx, int idx)

{

    return CRYPTO_get_ex_data(&dctx->ex_data, idx);

}

crypto/rand/drbg_rand.c

0 → 100644
+449 −0
Original line number Diff line number Diff line 
/*

 * Copyright 2011-2017 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (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 <stdlib.h>

#include <string.h>

#include <openssl/crypto.h>

#include <openssl/err.h>

#include <openssl/rand.h>

#include "rand_lcl.h"

#include "internal/thread_once.h"



/*

 * Mapping of NIST SP 800-90A DRBG to OpenSSL RAND_METHOD.

 */





/*

 * The default global DRBG and its auto-init/auto-cleanup.

 */

static DRBG_CTX ossl_drbg;



static CRYPTO_ONCE ossl_drbg_init = CRYPTO_ONCE_STATIC_INIT;



DEFINE_RUN_ONCE_STATIC(do_ossl_drbg_init)

{

    ossl_drbg.lock = CRYPTO_THREAD_lock_new();

    return ossl_drbg.lock != NULL;

}



void rand_drbg_cleanup(void)

{

    CRYPTO_THREAD_lock_free(ossl_drbg.lock);

}



static void inc_128(DRBG_CTR_CTX *cctx)

{

    int i;

    unsigned char c;

    unsigned char *p = &cctx->V[15];



    for (i = 0; i < 16; i++, p--) {

        c = *p;

        c++;

        *p = c;

        if (c != 0) {

            /* If we didn't wrap around, we're done. */

            break;

        }

    }

}



static void ctr_XOR(DRBG_CTR_CTX *cctx, const unsigned char *in, size_t inlen)

{

    size_t i, n;



    if (in == NULL || inlen == 0)

        return;



    /*

     * Any zero padding will have no effect on the result as we

     * are XORing. So just process however much input we have.

     */

    n = inlen < cctx->keylen ? inlen : cctx->keylen;

    for (i = 0; i < n; i++)

        cctx->K[i] ^= in[i];

    if (inlen <= cctx->keylen)

        return;



    n = inlen - cctx->keylen;

    if (n > 16) {

        /* Should never happen */

        n = 16;

    }

    for (i = 0; i < 16; i++)

        cctx->V[i] ^= in[i + cctx->keylen];

}



/*

 * Process a complete block using BCC algorithm of SP 800-90A 10.3.3

 */

static void ctr_BCC_block(DRBG_CTR_CTX *cctx, unsigned char *out,

                          const unsigned char *in)

{

    int i;



    for (i = 0; i < 16; i++)

        out[i] ^= in[i];

    AES_encrypt(out, out, &cctx->df_ks);

}





/*

 * Handle several BCC operations for as much data as we need for K and X

 */

static void ctr_BCC_blocks(DRBG_CTR_CTX *cctx, const unsigned char *in)

{

    ctr_BCC_block(cctx, cctx->KX, in);

    ctr_BCC_block(cctx, cctx->KX + 16, in);

    if (cctx->keylen != 16)

        ctr_BCC_block(cctx, cctx->KX + 32, in);

}



/*

 * Initialise BCC blocks: these have the value 0,1,2 in leftmost positions:

 * see 10.3.1 stage 7.

 */

static void ctr_BCC_init(DRBG_CTR_CTX *cctx)

{

    memset(cctx->KX, 0, 48);

    memset(cctx->bltmp, 0, 16);

    ctr_BCC_block(cctx, cctx->KX, cctx->bltmp);

    cctx->bltmp[3] = 1;

    ctr_BCC_block(cctx, cctx->KX + 16, cctx->bltmp);

    if (cctx->keylen != 16) {

        cctx->bltmp[3] = 2;

        ctr_BCC_block(cctx, cctx->KX + 32, cctx->bltmp);

    }

}



/*

 * Process several blocks into BCC algorithm, some possibly partial

 */

static void ctr_BCC_update(DRBG_CTR_CTX *cctx,

                           const unsigned char *in, size_t inlen)

{

    if (in == NULL || inlen == 0)

        return;



    /* If we have partial block handle it first */

    if (cctx->bltmp_pos) {

        size_t left = 16 - cctx->bltmp_pos;



        /* If we now have a complete block process it */

        if (inlen >= left) {

            memcpy(cctx->bltmp + cctx->bltmp_pos, in, left);

            ctr_BCC_blocks(cctx, cctx->bltmp);

            cctx->bltmp_pos = 0;

            inlen -= left;

            in += left;

        }

    }



    /* Process zero or more complete blocks */

    for (; inlen >= 16; in += 16, inlen -= 16) {

        ctr_BCC_blocks(cctx, in);

    }



    /* Copy any remaining partial block to the temporary buffer */

    if (inlen > 0) {

        memcpy(cctx->bltmp + cctx->bltmp_pos, in, inlen);

        cctx->bltmp_pos += inlen;

    }

}



static void ctr_BCC_final(DRBG_CTR_CTX *cctx)

{

    if (cctx->bltmp_pos) {

        memset(cctx->bltmp + cctx->bltmp_pos, 0, 16 - cctx->bltmp_pos);

        ctr_BCC_blocks(cctx, cctx->bltmp);

    }

}



static void ctr_df(DRBG_CTR_CTX *cctx,

                   const unsigned char *in1, size_t in1len,

                   const unsigned char *in2, size_t in2len,

                   const unsigned char *in3, size_t in3len)

{

    static unsigned char c80 = 0x80;

    size_t inlen;

    unsigned char *p = cctx->bltmp;



    ctr_BCC_init(cctx);

    if (in1 == NULL)

        in1len = 0;

    if (in2 == NULL)

        in2len = 0;

    if (in3 == NULL)

        in3len = 0;

    inlen = in1len + in2len + in3len;

    /* Initialise L||N in temporary block */

    *p++ = (inlen >> 24) & 0xff;

    *p++ = (inlen >> 16) & 0xff;

    *p++ = (inlen >> 8) & 0xff;

    *p++ = inlen & 0xff;



    /* NB keylen is at most 32 bytes */

    *p++ = 0;

    *p++ = 0;

    *p++ = 0;

    *p = (unsigned char)((cctx->keylen + 16) & 0xff);

    cctx->bltmp_pos = 8;

    ctr_BCC_update(cctx, in1, in1len);

    ctr_BCC_update(cctx, in2, in2len);

    ctr_BCC_update(cctx, in3, in3len);

    ctr_BCC_update(cctx, &c80, 1);

    ctr_BCC_final(cctx);

    /* Set up key K */

    AES_set_encrypt_key(cctx->KX, cctx->keylen * 8, &cctx->df_kxks);

    /* X follows key K */

    AES_encrypt(cctx->KX + cctx->keylen, cctx->KX, &cctx->df_kxks);

    AES_encrypt(cctx->KX, cctx->KX + 16, &cctx->df_kxks);

    if (cctx->keylen != 16)

        AES_encrypt(cctx->KX + 16, cctx->KX + 32, &cctx->df_kxks);

}



/*

 * NB the no-df Update in SP800-90A specifies a constant input length

 * of seedlen, however other uses of this algorithm pad the input with

 * zeroes if necessary and have up to two parameters XORed together,

 * handle both cases in this function instead.

 */

static void ctr_update(DRBG_CTX *dctx,

                       const unsigned char *in1, size_t in1len,

                       const unsigned char *in2, size_t in2len,

                       const unsigned char *nonce, size_t noncelen)

{

    DRBG_CTR_CTX *cctx = &dctx->ctr;



    /* ks is already setup for correct key */

    inc_128(cctx);

    AES_encrypt(cctx->V, cctx->K, &cctx->ks);



    /* If keylen longer than 128 bits need extra encrypt */

    if (cctx->keylen != 16) {

        inc_128(cctx);

        AES_encrypt(cctx->V, cctx->K + 16, &cctx->ks);

    }

    inc_128(cctx);

    AES_encrypt(cctx->V, cctx->V, &cctx->ks);



    /* If 192 bit key part of V is on end of K */

    if (cctx->keylen == 24) {

        memcpy(cctx->V + 8, cctx->V, 8);

        memcpy(cctx->V, cctx->K + 24, 8);

    }



    if (dctx->flags & RAND_DRBG_FLAG_CTR_USE_DF) {

        /* If no input reuse existing derived value */

        if (in1 != NULL || nonce != NULL || in2 != NULL)

            ctr_df(cctx, in1, in1len, nonce, noncelen, in2, in2len);

        /* If this a reuse input in1len != 0 */

        if (in1len)

            ctr_XOR(cctx, cctx->KX, dctx->seedlen);

    } else {

        ctr_XOR(cctx, in1, in1len);

        ctr_XOR(cctx, in2, in2len);

    }



    AES_set_encrypt_key(cctx->K, dctx->strength, &cctx->ks);

}



int ctr_instantiate(DRBG_CTX *dctx,

                    const unsigned char *ent, size_t entlen,

                    const unsigned char *nonce, size_t noncelen,

                    const unsigned char *pers, size_t perslen)

{

    DRBG_CTR_CTX *cctx = &dctx->ctr;



    memset(cctx->K, 0, sizeof(cctx->K));

    memset(cctx->V, 0, sizeof(cctx->V));

    AES_set_encrypt_key(cctx->K, dctx->strength, &cctx->ks);

    ctr_update(dctx, ent, entlen, pers, perslen, nonce, noncelen);

    return 1;

}



int ctr_reseed(DRBG_CTX *dctx,

               const unsigned char *ent, size_t entlen,

               const unsigned char *adin, size_t adinlen)

{

    ctr_update(dctx, ent, entlen, adin, adinlen, NULL, 0);

    return 1;

}



int ctr_generate(DRBG_CTX *dctx,

                 unsigned char *out, size_t outlen,

                 const unsigned char *adin, size_t adinlen)

{

    DRBG_CTR_CTX *cctx = &dctx->ctr;



    if (adin != NULL && adinlen != 0) {

        ctr_update(dctx, adin, adinlen, NULL, 0, NULL, 0);

        /* This means we reuse derived value */

        if (dctx->flags & RAND_DRBG_FLAG_CTR_USE_DF) {

            adin = NULL;

            adinlen = 1;

        }

    } else {

        adinlen = 0;

    }



    for ( ; ; ) {

        inc_128(cctx);

        if (outlen < 16) {

            /* Use K as temp space as it will be updated */

            AES_encrypt(cctx->V, cctx->K, &cctx->ks);

            memcpy(out, cctx->K, outlen);

            break;

        }

        AES_encrypt(cctx->V, out, &cctx->ks);

        out += 16;

        outlen -= 16;

        if (outlen == 0)

            break;

    }



    ctr_update(dctx, adin, adinlen, NULL, 0, NULL, 0);

    return 1;

}



int ctr_uninstantiate(DRBG_CTX *dctx)

{

    memset(&dctx->ctr, 0, sizeof(dctx->ctr));

    return 1;

}



int ctr_init(DRBG_CTX *dctx)

{

    DRBG_CTR_CTX *cctx = &dctx->ctr;

    size_t keylen;



    switch (dctx->nid) {

    default:

        /* This can't happen, but silence the compiler warning. */

        return -1;

    case NID_aes_128_ctr:

        keylen = 16;

        break;

    case NID_aes_192_ctr:

        keylen = 24;

        break;

    case NID_aes_256_ctr:

        keylen = 32;

        break;

    }



    cctx->keylen = keylen;

    dctx->strength = keylen * 8;

    dctx->blocklength = 16;

    dctx->seedlen = keylen + 16;



    if (dctx->flags & RAND_DRBG_FLAG_CTR_USE_DF) {

        /* df initialisation */

        static unsigned char df_key[32] = {

            0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,

            0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f,

            0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,

            0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1e,0x1f

        };

        /* Set key schedule for df_key */

        AES_set_encrypt_key(df_key, dctx->strength, &cctx->df_ks);



        dctx->min_entropy = cctx->keylen;

        dctx->max_entropy = DRBG_MAX_LENGTH;

        dctx->min_nonce = dctx->min_entropy / 2;

        dctx->max_nonce = DRBG_MAX_LENGTH;

        dctx->max_pers = DRBG_MAX_LENGTH;

        dctx->max_adin = DRBG_MAX_LENGTH;

    } else {

        dctx->min_entropy = dctx->seedlen;

        dctx->max_entropy = dctx->seedlen;

        /* Nonce not used */

        dctx->min_nonce = 0;

        dctx->max_nonce = 0;

        dctx->max_pers = dctx->seedlen;

        dctx->max_adin = dctx->seedlen;

    }



    dctx->max_request = 1 << 16;

    dctx->reseed_interval = 1 << 24;

    return 1;

}





/*

 * The following function tie the DRBG code into the RAND_METHOD

 */



DRBG_CTX *RAND_DRBG_get_default(void)

{

    if (!RUN_ONCE(&ossl_drbg_init, do_ossl_drbg_init))

        return NULL;

    return &ossl_drbg;

}



static int drbg_bytes(unsigned char *out, int count)

{

    DRBG_CTX *dctx = RAND_DRBG_get_default();

    int ret = 0;



    CRYPTO_THREAD_write_lock(dctx->lock);

    do {

        size_t rcnt;



        if (count > (int)dctx->max_request)

            rcnt = dctx->max_request;

        else

            rcnt = count;

        ret = RAND_DRBG_generate(dctx, out, rcnt, 0, NULL, 0);

        if (!ret)

            goto err;

        out += rcnt;

        count -= rcnt;

    } while (count);

    ret = 1;

err:

    CRYPTO_THREAD_unlock(dctx->lock);

    return ret;

}



static int drbg_status(void)

{

    DRBG_CTX *dctx = RAND_DRBG_get_default();

    int ret;



    CRYPTO_THREAD_write_lock(dctx->lock);

    ret = dctx->status == DRBG_STATUS_READY ? 1 : 0;

    CRYPTO_THREAD_unlock(dctx->lock);

    return ret;

}



static void drbg_cleanup(void)

{

    DRBG_CTX *dctx = RAND_DRBG_get_default();



    CRYPTO_THREAD_write_lock(dctx->lock);

    RAND_DRBG_uninstantiate(dctx);

    CRYPTO_THREAD_unlock(dctx->lock);

}



static const RAND_METHOD rand_drbg_meth =

{

    NULL,

    drbg_bytes,

    drbg_cleanup,

    NULL,

    drbg_bytes,

    drbg_status

};



const RAND_METHOD *RAND_drbg(void)

{

    return &rand_drbg_meth;

}

crypto/rand/ossl_rand.c

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