[thirdparty/openssl.git] / providers / implementations / kdfs / krb5kdf.c

/*
 * Copyright 2018-2020 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
 */

/*
 * DES low level APIs are deprecated for public use, but still ok for internal
 * use.  We access the DES_set_odd_parity(3) function here.
 */
#include "internal/deprecated.h"

#include <stdlib.h>
#include <stdarg.h>
#include <string.h>

#include <openssl/core_names.h>
#include <openssl/des.h>
#include <openssl/evp.h>
#include <openssl/kdf.h>

#include "internal/cryptlib.h"
#include "crypto/evp.h"
#include "internal/numbers.h"
#include "prov/implementations.h"
#include "prov/provider_ctx.h"
#include "prov/provider_util.h"
#include "prov/providercommon.h"
#include "prov/providercommonerr.h"

/* KRB5 KDF defined in RFC 3961, Section 5.1 */

static OSSL_FUNC_kdf_newctx_fn krb5kdf_new;
static OSSL_FUNC_kdf_freectx_fn krb5kdf_free;
static OSSL_FUNC_kdf_reset_fn krb5kdf_reset;
static OSSL_FUNC_kdf_derive_fn krb5kdf_derive;
static OSSL_FUNC_kdf_settable_ctx_params_fn krb5kdf_settable_ctx_params;
static OSSL_FUNC_kdf_set_ctx_params_fn krb5kdf_set_ctx_params;
static OSSL_FUNC_kdf_gettable_ctx_params_fn krb5kdf_gettable_ctx_params;
static OSSL_FUNC_kdf_get_ctx_params_fn krb5kdf_get_ctx_params;

static int KRB5KDF(const EVP_CIPHER *cipher, ENGINE *engine,
                   const unsigned char *key, size_t key_len,
                   const unsigned char *constant, size_t constant_len,
                   unsigned char *okey, size_t okey_len);

typedef struct {
    void *provctx;
    PROV_CIPHER cipher;
    unsigned char *key;
    size_t key_len;
    unsigned char *constant;
    size_t constant_len;
} KRB5KDF_CTX;

static void *krb5kdf_new(void *provctx)
{
    KRB5KDF_CTX *ctx;

    if (!ossl_prov_is_running())
        return NULL;

    if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
        ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
    ctx->provctx = provctx;
    return ctx;
}

static void krb5kdf_free(void *vctx)
{
    KRB5KDF_CTX *ctx = (KRB5KDF_CTX *)vctx;

    if (ctx != NULL) {
        krb5kdf_reset(ctx);
        OPENSSL_free(ctx);
    }
}

static void krb5kdf_reset(void *vctx)
{
    KRB5KDF_CTX *ctx = (KRB5KDF_CTX *)vctx;
    void *provctx = ctx->provctx;

    ossl_prov_cipher_reset(&ctx->cipher);
    OPENSSL_clear_free(ctx->key, ctx->key_len);
    OPENSSL_clear_free(ctx->constant, ctx->constant_len);
    memset(ctx, 0, sizeof(*ctx));
    ctx->provctx = provctx;
}

static int krb5kdf_set_membuf(unsigned char **dst, size_t *dst_len,
                              const OSSL_PARAM *p)
{
    OPENSSL_clear_free(*dst, *dst_len);
    *dst = NULL;
    return OSSL_PARAM_get_octet_string(p, (void **)dst, 0, dst_len);
}

static int krb5kdf_derive(void *vctx, unsigned char *key,
                              size_t keylen)
{
    KRB5KDF_CTX *ctx = (KRB5KDF_CTX *)vctx;
    const EVP_CIPHER *cipher;
    ENGINE *engine;

    if (!ossl_prov_is_running())
        return 0;

    cipher = ossl_prov_cipher_cipher(&ctx->cipher);
    if (cipher == NULL) {
        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CIPHER);
        return 0;
    }
    if (ctx->key == NULL) {
        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
        return 0;
    }
    if (ctx->constant == NULL) {
        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CONSTANT);
        return 0;
    }
    engine = ossl_prov_cipher_engine(&ctx->cipher);
    return KRB5KDF(cipher, engine, ctx->key, ctx->key_len,
                   ctx->constant, ctx->constant_len,
                   key, keylen);
}

static int krb5kdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
{
    const OSSL_PARAM *p;
    KRB5KDF_CTX *ctx = vctx;
    OSSL_LIB_CTX *provctx = PROV_LIBRARY_CONTEXT_OF(ctx->provctx);

    if (!ossl_prov_cipher_load_from_params(&ctx->cipher, params, provctx))
        return 0;

    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
        if (!krb5kdf_set_membuf(&ctx->key, &ctx->key_len, p))
            return 0;

    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_CONSTANT))
        != NULL)
        if (!krb5kdf_set_membuf(&ctx->constant, &ctx->constant_len, p))
            return 0;

    return 1;
}

static const OSSL_PARAM *krb5kdf_settable_ctx_params(ossl_unused void *provctx)
{
    static const OSSL_PARAM known_settable_ctx_params[] = {
        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CIPHER, NULL, 0),
        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_CONSTANT, NULL, 0),
        OSSL_PARAM_END
    };
    return known_settable_ctx_params;
}

static int krb5kdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
{
    KRB5KDF_CTX *ctx = (KRB5KDF_CTX *)vctx;
    const EVP_CIPHER *cipher;
    size_t len;
    OSSL_PARAM *p;

    cipher = ossl_prov_cipher_cipher(&ctx->cipher);
    if (cipher)
        len = EVP_CIPHER_key_length(cipher);
    else
        len = EVP_MAX_KEY_LENGTH;

    if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
        return OSSL_PARAM_set_size_t(p, len);
    return -2;
}

static const OSSL_PARAM *krb5kdf_gettable_ctx_params(ossl_unused void *provctx)
{
    static const OSSL_PARAM known_gettable_ctx_params[] = {
        OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
        OSSL_PARAM_END
    };
    return known_gettable_ctx_params;
}

const OSSL_DISPATCH ossl_kdf_krb5kdf_functions[] = {
    { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))krb5kdf_new },
    { OSSL_FUNC_KDF_FREECTX, (void(*)(void))krb5kdf_free },
    { OSSL_FUNC_KDF_RESET, (void(*)(void))krb5kdf_reset },
    { OSSL_FUNC_KDF_DERIVE, (void(*)(void))krb5kdf_derive },
    { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
      (void(*)(void))krb5kdf_settable_ctx_params },
    { OSSL_FUNC_KDF_SET_CTX_PARAMS,
      (void(*)(void))krb5kdf_set_ctx_params },
    { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
      (void(*)(void))krb5kdf_gettable_ctx_params },
    { OSSL_FUNC_KDF_GET_CTX_PARAMS,
      (void(*)(void))krb5kdf_get_ctx_params },
    { 0, NULL }
};

#ifndef OPENSSL_NO_DES
/*
 * DES3 is a special case, it requires a random-to-key function and its
 * input truncated to 21 bytes of the 24 produced by the cipher.
 * See RFC3961 6.3.1
 */
static int fixup_des3_key(unsigned char *key)
{
    unsigned char *cblock;
    int i, j;

    for (i = 2; i >= 0; i--) {
        cblock = &key[i * 8];
        memmove(cblock, &key[i * 7], 7);
        cblock[7] = 0;
        for (j = 0; j < 7; j++)
            cblock[7] |= (cblock[j] & 1) << (j + 1);
        DES_set_odd_parity((DES_cblock *)cblock);
    }

    /* fail if keys are such that triple des degrades to single des */
    if (CRYPTO_memcmp(&key[0], &key[8], 8) == 0 ||
        CRYPTO_memcmp(&key[8], &key[16], 8) == 0) {
        return 0;
    }

    return 1;
}
#endif

/*
 * N-fold(K) where blocksize is N, and constant_len is K
 * Note: Here |= denotes concatenation
 *
 * L = lcm(N,K)
 * R = L/K
 *
 * for r: 1 -> R
 *   s |= constant rot 13*(r-1))
 *
 * block = 0
 * for k: 1 -> K
 *   block += s[N(k-1)..(N-1)k] (one's complement addition)
 *
 * Optimizing for space we compute:
 * for each l in L-1 -> 0:
 *   s[l] = (constant rot 13*(l/K))[l%k]
 *   block[l % N] += s[l] (with carry)
 * finally add carry if any
 */
static void n_fold(unsigned char *block, unsigned int blocksize,
                   const unsigned char *constant, size_t constant_len)
{
    unsigned int tmp, gcd, remainder, lcm, carry;
    int b, l;

    if (constant_len == blocksize) {
        memcpy(block, constant, constant_len);
        return;
    }

    /* Least Common Multiple of lengths: LCM(a,b)*/
    gcd = blocksize;
    remainder = constant_len;
    /* Calculate Great Common Divisor first GCD(a,b) */
    while (remainder != 0) {
        tmp = gcd % remainder;
        gcd = remainder;
        remainder = tmp;
    }
    /* resulting a is the GCD, LCM(a,b) = |a*b|/GCD(a,b) */
    lcm = blocksize * constant_len / gcd;

    /* now spread out the bits */
    memset(block, 0, blocksize);

    /* last to first to be able to bring carry forward */
    carry = 0;
    for (l = lcm - 1; l >= 0; l--) {
        unsigned int rotbits, rshift, rbyte;

        /* destination byte in block is l % N */
        b = l % blocksize;
        /* Our virtual s buffer is R = L/K long (K = constant_len) */
        /* So we rotate backwards from R-1 to 0 (none) rotations */
        rotbits = 13 * (l / constant_len);
        /* find the byte on s where rotbits falls onto */
        rbyte = l - (rotbits / 8);
        /* calculate how much shift on that byte */
        rshift = rotbits & 0x07;
        /* rbyte % constant_len gives us the unrotated byte in the
         * constant buffer, get also the previous byte then
         * appropriately shift them to get the rotated byte we need */
        tmp = (constant[(rbyte-1) % constant_len] << (8 - rshift)
               | constant[rbyte % constant_len] >> rshift)
              & 0xff;
        /* add with carry to any value placed by previous passes */
        tmp += carry + block[b];
        block[b] = tmp & 0xff;
        /* save any carry that may be left */
        carry = tmp >> 8;
    }

    /* if any carry is left at the end, add it through the number */
    for (b = blocksize - 1; b >= 0 && carry != 0; b--) {
        carry += block[b];
        block[b] = carry & 0xff;
        carry >>= 8;
    }
}

static int cipher_init(EVP_CIPHER_CTX *ctx,
                       const EVP_CIPHER *cipher, ENGINE *engine,
                       const unsigned char *key, size_t key_len)
{
    int klen, ret;

    ret = EVP_EncryptInit_ex(ctx, cipher, engine, key, NULL);
    if (!ret)
        goto out;
    /* set the key len for the odd variable key len cipher */
    klen = EVP_CIPHER_CTX_key_length(ctx);
    if (key_len != (size_t)klen) {
        ret = EVP_CIPHER_CTX_set_key_length(ctx, key_len);
        if (!ret)
            goto out;
    }
    /* we never want padding, either the length requested is a multiple of
     * the cipher block size or we are passed a cipher that can cope with
     * partial blocks via techniques like cipher text stealing */
    ret = EVP_CIPHER_CTX_set_padding(ctx, 0);
    if (!ret)
        goto out;

out:
    return ret;
}

static int KRB5KDF(const EVP_CIPHER *cipher, ENGINE *engine,
                   const unsigned char *key, size_t key_len,
                   const unsigned char *constant, size_t constant_len,
                   unsigned char *okey, size_t okey_len)
{
    EVP_CIPHER_CTX *ctx = NULL;
    unsigned char block[EVP_MAX_BLOCK_LENGTH * 2];
    unsigned char *plainblock, *cipherblock;
    size_t blocksize;
    size_t cipherlen;
    size_t osize;
#ifndef OPENSSL_NO_DES
    int des3_no_fixup = 0;
#endif
    int ret;

    if (key_len != okey_len) {
#ifndef OPENSSL_NO_DES
        /* special case for 3des, where the caller may be requesting
         * the random raw key, instead of the fixed up key  */
        if (EVP_CIPHER_nid(cipher) == NID_des_ede3_cbc &&
            key_len == 24 && okey_len == 21) {
                des3_no_fixup = 1;
        } else {
#endif
            ERR_raise(ERR_LIB_PROV, PROV_R_WRONG_OUTPUT_BUFFER_SIZE);
            return 0;
#ifndef OPENSSL_NO_DES
        }
#endif
    }

    ctx = EVP_CIPHER_CTX_new();
    if (ctx == NULL)
        return 0;

    ret = cipher_init(ctx, cipher, engine, key, key_len);
    if (!ret)
        goto out;

    /* Initialize input block */
    blocksize = EVP_CIPHER_CTX_block_size(ctx);

    if (constant_len > blocksize) {
        ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CONSTANT_LENGTH);
        ret = 0;
        goto out;
    }

    n_fold(block, blocksize, constant, constant_len);
    plainblock = block;
    cipherblock = block + EVP_MAX_BLOCK_LENGTH;

    for (osize = 0; osize < okey_len; osize += cipherlen) {
        int olen;

        ret = EVP_EncryptUpdate(ctx, cipherblock, &olen,
                                plainblock, blocksize);
        if (!ret)
            goto out;
        cipherlen = olen;
        ret = EVP_EncryptFinal_ex(ctx, cipherblock, &olen);
        if (!ret)
            goto out;
        if (olen != 0) {
            ERR_raise(ERR_LIB_PROV, PROV_R_WRONG_FINAL_BLOCK_LENGTH);
            ret = 0;
            goto out;
        }

        /* write cipherblock out */
        if (cipherlen > okey_len - osize)
            cipherlen = okey_len - osize;
        memcpy(okey + osize, cipherblock, cipherlen);

        if (okey_len > osize + cipherlen) {
            /* we need to reinitialize cipher context per spec */
            ret = EVP_CIPHER_CTX_reset(ctx);
            if (!ret)
                goto out;
            ret = cipher_init(ctx, cipher, engine, key, key_len);
            if (!ret)
                goto out;

            /* also swap block offsets so last ciphertext becomes new
             * plaintext */
            plainblock = cipherblock;
            if (cipherblock == block) {
                cipherblock += EVP_MAX_BLOCK_LENGTH;
            } else {
                cipherblock = block;
            }
        }
    }

#ifndef OPENSSL_NO_DES
    if (EVP_CIPHER_nid(cipher) == NID_des_ede3_cbc && !des3_no_fixup) {
        ret = fixup_des3_key(okey);
        if (!ret) {
            ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GENERATE_KEY);
            goto out;
        }
    }
#endif

    ret = 1;

out:
    EVP_CIPHER_CTX_free(ctx);
    OPENSSL_cleanse(block, EVP_MAX_BLOCK_LENGTH * 2);
    return ret;
}
Commit	Line	Data
33f54da3	1	/*
33388b44	2	* Copyright 2018-2020 The OpenSSL Project Authors. All Rights Reserved.
33f54da3	3	*
a6ed19dc	4	* Licensed under the Apache License 2.0 (the "License"). You may not use
33f54da3 SS	5	* this file except in compliance with the License. You can obtain a copy
	6	* in the file LICENSE in the source distribution or at
	7	* https://www.openssl.org/source/license.html
	8	*/
	9
c6fec81b P	10	/*
	11	* DES low level APIs are deprecated for public use, but still ok for internal
	12	* use. We access the DES_set_odd_parity(3) function here.
	13	*/
	14	#include "internal/deprecated.h"
	15
33f54da3 SS	16	#include <stdlib.h>
	17	#include <stdarg.h>
	18	#include <string.h>
	19
	20	#include <openssl/core_names.h>
	21	#include <openssl/des.h>
	22	#include <openssl/evp.h>
	23	#include <openssl/kdf.h>
	24
	25	#include "internal/cryptlib.h"
	26	#include "crypto/evp.h"
	27	#include "internal/numbers.h"
	28	#include "prov/implementations.h"
	29	#include "prov/provider_ctx.h"
	30	#include "prov/provider_util.h"
2b9e4e95	31	#include "prov/providercommon.h"
33f54da3 SS	32	#include "prov/providercommonerr.h"
	33
	34	/* KRB5 KDF defined in RFC 3961, Section 5.1 */
	35
363b1e5d DMSP	36	static OSSL_FUNC_kdf_newctx_fn krb5kdf_new;
	37	static OSSL_FUNC_kdf_freectx_fn krb5kdf_free;
	38	static OSSL_FUNC_kdf_reset_fn krb5kdf_reset;
	39	static OSSL_FUNC_kdf_derive_fn krb5kdf_derive;
	40	static OSSL_FUNC_kdf_settable_ctx_params_fn krb5kdf_settable_ctx_params;
	41	static OSSL_FUNC_kdf_set_ctx_params_fn krb5kdf_set_ctx_params;
	42	static OSSL_FUNC_kdf_gettable_ctx_params_fn krb5kdf_gettable_ctx_params;
	43	static OSSL_FUNC_kdf_get_ctx_params_fn krb5kdf_get_ctx_params;
33f54da3 SS	44
	45	static int KRB5KDF(const EVP_CIPHER cipher, ENGINE engine,
	46	const unsigned char *key, size_t key_len,
	47	const unsigned char *constant, size_t constant_len,
	48	unsigned char *okey, size_t okey_len);
	49
	50	typedef struct {
	51	void *provctx;
	52	PROV_CIPHER cipher;
	53	unsigned char *key;
	54	size_t key_len;
	55	unsigned char *constant;
	56	size_t constant_len;
	57	} KRB5KDF_CTX;
	58
	59	static void krb5kdf_new(void provctx)
	60	{
	61	KRB5KDF_CTX *ctx;
	62
2b9e4e95 P	63	if (!ossl_prov_is_running())
	64	return NULL;
	65
33f54da3 SS	66	if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
	67	ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
	68	ctx->provctx = provctx;
	69	return ctx;
	70	}
	71
	72	static void krb5kdf_free(void *vctx)
	73	{
	74	KRB5KDF_CTX ctx = (KRB5KDF_CTX )vctx;
	75
3c659415 P	76	if (ctx != NULL) {
	77	krb5kdf_reset(ctx);
	78	OPENSSL_free(ctx);
	79	}
33f54da3 SS	80	}
	81
	82	static void krb5kdf_reset(void *vctx)
	83	{
	84	KRB5KDF_CTX ctx = (KRB5KDF_CTX )vctx;
0577959c	85	void *provctx = ctx->provctx;
33f54da3 SS	86
	87	ossl_prov_cipher_reset(&ctx->cipher);
	88	OPENSSL_clear_free(ctx->key, ctx->key_len);
	89	OPENSSL_clear_free(ctx->constant, ctx->constant_len);
	90	memset(ctx, 0, sizeof(*ctx));
0577959c	91	ctx->provctx = provctx;
33f54da3 SS	92	}
	93
	94	static int krb5kdf_set_membuf(unsigned char *dst, size_t dst_len,
	95	const OSSL_PARAM *p)
	96	{
	97	OPENSSL_clear_free(dst, dst_len);
	98	*dst = NULL;
	99	return OSSL_PARAM_get_octet_string(p, (void **)dst, 0, dst_len);
	100	}
	101
	102	static int krb5kdf_derive(void vctx, unsigned char key,
	103	size_t keylen)
	104	{
	105	KRB5KDF_CTX ctx = (KRB5KDF_CTX )vctx;
2b9e4e95 P	106	const EVP_CIPHER *cipher;
	107	ENGINE *engine;
	108
	109	if (!ossl_prov_is_running())
	110	return 0;
33f54da3	111
2b9e4e95	112	cipher = ossl_prov_cipher_cipher(&ctx->cipher);
33f54da3 SS	113	if (cipher == NULL) {
	114	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CIPHER);
	115	return 0;
	116	}
	117	if (ctx->key == NULL) {
	118	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
	119	return 0;
	120	}
	121	if (ctx->constant == NULL) {
	122	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CONSTANT);
	123	return 0;
	124	}
2b9e4e95	125	engine = ossl_prov_cipher_engine(&ctx->cipher);
33f54da3 SS	126	return KRB5KDF(cipher, engine, ctx->key, ctx->key_len,
	127	ctx->constant, ctx->constant_len,
	128	key, keylen);
	129	}
	130
	131	static int krb5kdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
	132	{
	133	const OSSL_PARAM *p;
	134	KRB5KDF_CTX *ctx = vctx;
b4250010	135	OSSL_LIB_CTX *provctx = PROV_LIBRARY_CONTEXT_OF(ctx->provctx);
33f54da3 SS	136
	137	if (!ossl_prov_cipher_load_from_params(&ctx->cipher, params, provctx))
	138	return 0;
	139
	140	if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
	141	if (!krb5kdf_set_membuf(&ctx->key, &ctx->key_len, p))
	142	return 0;
	143
	144	if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_CONSTANT))
	145	!= NULL)
	146	if (!krb5kdf_set_membuf(&ctx->constant, &ctx->constant_len, p))
	147	return 0;
	148
	149	return 1;
	150	}
	151
1017ab21	152	static const OSSL_PARAM krb5kdf_settable_ctx_params(ossl_unused void provctx)
33f54da3 SS	153	{
	154	static const OSSL_PARAM known_settable_ctx_params[] = {
	155	OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
	156	OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CIPHER, NULL, 0),
	157	OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
	158	OSSL_PARAM_octet_string(OSSL_KDF_PARAM_CONSTANT, NULL, 0),
	159	OSSL_PARAM_END
	160	};
	161	return known_settable_ctx_params;
	162	}
	163
	164	static int krb5kdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
	165	{
	166	KRB5KDF_CTX ctx = (KRB5KDF_CTX )vctx;
	167	const EVP_CIPHER *cipher;
	168	size_t len;
	169	OSSL_PARAM *p;
	170
	171	cipher = ossl_prov_cipher_cipher(&ctx->cipher);
	172	if (cipher)
	173	len = EVP_CIPHER_key_length(cipher);
	174	else
	175	len = EVP_MAX_KEY_LENGTH;
	176
	177	if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
	178	return OSSL_PARAM_set_size_t(p, len);
	179	return -2;
	180	}
	181
1017ab21	182	static const OSSL_PARAM krb5kdf_gettable_ctx_params(ossl_unused void provctx)
33f54da3 SS	183	{
	184	static const OSSL_PARAM known_gettable_ctx_params[] = {
	185	OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
	186	OSSL_PARAM_END
	187	};
	188	return known_gettable_ctx_params;
	189	}
	190
1be63951	191	const OSSL_DISPATCH ossl_kdf_krb5kdf_functions[] = {
33f54da3 SS	192	{ OSSL_FUNC_KDF_NEWCTX, (void(*)(void))krb5kdf_new },
	193	{ OSSL_FUNC_KDF_FREECTX, (void(*)(void))krb5kdf_free },
	194	{ OSSL_FUNC_KDF_RESET, (void(*)(void))krb5kdf_reset },
	195	{ OSSL_FUNC_KDF_DERIVE, (void(*)(void))krb5kdf_derive },
	196	{ OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
	197	(void(*)(void))krb5kdf_settable_ctx_params },
	198	{ OSSL_FUNC_KDF_SET_CTX_PARAMS,
	199	(void(*)(void))krb5kdf_set_ctx_params },
	200	{ OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
	201	(void(*)(void))krb5kdf_gettable_ctx_params },
	202	{ OSSL_FUNC_KDF_GET_CTX_PARAMS,
	203	(void(*)(void))krb5kdf_get_ctx_params },
	204	{ 0, NULL }
	205	};
	206
	207	#ifndef OPENSSL_NO_DES
	208	/*
	209	* DES3 is a special case, it requires a random-to-key function and its
	210	* input truncated to 21 bytes of the 24 produced by the cipher.
	211	* See RFC3961 6.3.1
	212	*/
	213	static int fixup_des3_key(unsigned char *key)
	214	{
	215	unsigned char *cblock;
	216	int i, j;
	217
	218	for (i = 2; i >= 0; i--) {
	219	cblock = &key[i * 8];
	220	memmove(cblock, &key[i * 7], 7);
	221	cblock[7] = 0;
	222	for (j = 0; j < 7; j++)
	223	cblock[7] \|= (cblock[j] & 1) << (j + 1);
	224	DES_set_odd_parity((DES_cblock *)cblock);
	225	}
	226
	227	/* fail if keys are such that triple des degrades to single des */
	228	if (CRYPTO_memcmp(&key[0], &key[8], 8) == 0 \|\|
	229	CRYPTO_memcmp(&key[8], &key[16], 8) == 0) {
	230	return 0;
	231	}
	232
	233	return 1;
	234	}
	235	#endif
	236
	237	/*
	238	* N-fold(K) where blocksize is N, and constant_len is K
	239	* Note: Here \|= denotes concatenation
	240	*
	241	* L = lcm(N,K)
	242	* R = L/K
	243	*
	244	* for r: 1 -> R
	245	* s \|= constant rot 13*(r-1))
	246	*
	247	* block = 0
	248	* for k: 1 -> K
	249	* block += s[N(k-1)..(N-1)k] (one's complement addition)
	250	*
	251	* Optimizing for space we compute:
	252	* for each l in L-1 -> 0:
	253	* s[l] = (constant rot 13*(l/K))[l%k]
	254	* block[l % N] += s[l] (with carry)
	255	* finally add carry if any
256	*/
257	static void n_fold(unsigned char *block, unsigned int blocksize,
258	const unsigned char *constant, size_t constant_len)
259	{
260	unsigned int tmp, gcd, remainder, lcm, carry;
261	int b, l;
262
263	if (constant_len == blocksize) {
264	memcpy(block, constant, constant_len);
265	return;
266	}
267
268	/* Least Common Multiple of lengths: LCM(a,b)*/
269	gcd = blocksize;
270	remainder = constant_len;
271	/* Calculate Great Common Divisor first GCD(a,b) */
272	while (remainder != 0) {
273	tmp = gcd % remainder;
274	gcd = remainder;
275	remainder = tmp;
276	}
277	/* resulting a is the GCD, LCM(a,b) = \|ab\|/GCD(a,b) /
278	lcm = blocksize * constant_len / gcd;
279
280	/* now spread out the bits */
281	memset(block, 0, blocksize);
282
283	/* last to first to be able to bring carry forward */
284	carry = 0;
285	for (l = lcm - 1; l >= 0; l--) {
286	unsigned int rotbits, rshift, rbyte;
287
288	/* destination byte in block is l % N */
289	b = l % blocksize;
290	/* Our virtual s buffer is R = L/K long (K = constant_len) */
291	/* So we rotate backwards from R-1 to 0 (none) rotations */
292	rotbits = 13 * (l / constant_len);
293	/* find the byte on s where rotbits falls onto */
294	rbyte = l - (rotbits / 8);
295	/* calculate how much shift on that byte */
296	rshift = rotbits & 0x07;
297	/* rbyte % constant_len gives us the unrotated byte in the
298	* constant buffer, get also the previous byte then
299	* appropriately shift them to get the rotated byte we need */
300	tmp = (constant[(rbyte-1) % constant_len] << (8 - rshift)
301	\| constant[rbyte % constant_len] >> rshift)
302	& 0xff;
303	/* add with carry to any value placed by previous passes */
304	tmp += carry + block[b];
305	block[b] = tmp & 0xff;
306	/* save any carry that may be left */
307	carry = tmp >> 8;
308	}
309
310	/* if any carry is left at the end, add it through the number */
311	for (b = blocksize - 1; b >= 0 && carry != 0; b--) {
312	carry += block[b];
313	block[b] = carry & 0xff;
314	carry >>= 8;
315	}
316	}
317
318	static int cipher_init(EVP_CIPHER_CTX *ctx,
319	const EVP_CIPHER cipher, ENGINE engine,
320	const unsigned char *key, size_t key_len)
321	{
322	int klen, ret;
323
324	ret = EVP_EncryptInit_ex(ctx, cipher, engine, key, NULL);
325	if (!ret)
326	goto out;
327	/* set the key len for the odd variable key len cipher */
328	klen = EVP_CIPHER_CTX_key_length(ctx);
329	if (key_len != (size_t)klen) {
330	ret = EVP_CIPHER_CTX_set_key_length(ctx, key_len);
331	if (!ret)
332	goto out;
333	}
334	/* we never want padding, either the length requested is a multiple of
335	* the cipher block size or we are passed a cipher that can cope with
336	* partial blocks via techniques like cipher text stealing */
337	ret = EVP_CIPHER_CTX_set_padding(ctx, 0);
338	if (!ret)
339	goto out;
340
341	out:
342	return ret;
343	}
344
345	static int KRB5KDF(const EVP_CIPHER cipher, ENGINE engine,
346	const unsigned char *key, size_t key_len,
347	const unsigned char *constant, size_t constant_len,
348	unsigned char *okey, size_t okey_len)
349	{
350	EVP_CIPHER_CTX *ctx = NULL;
351	unsigned char block[EVP_MAX_BLOCK_LENGTH * 2];
352	unsigned char plainblock, cipherblock;
353	size_t blocksize;
354	size_t cipherlen;
355	size_t osize;
74a5808b	356	#ifndef OPENSSL_NO_DES
33f54da3	357	int des3_no_fixup = 0;
74a5808b	358	#endif
33f54da3 SS	359	int ret;
	360
	361	if (key_len != okey_len) {
74a5808b	362	#ifndef OPENSSL_NO_DES
33f54da3 SS	363	/* special case for 3des, where the caller may be requesting
	364	* the random raw key, instead of the fixed up key */
	365	if (EVP_CIPHER_nid(cipher) == NID_des_ede3_cbc &&
	366	key_len == 24 && okey_len == 21) {
	367	des3_no_fixup = 1;
	368	} else {
74a5808b	369	#endif
33f54da3 SS	370	ERR_raise(ERR_LIB_PROV, PROV_R_WRONG_OUTPUT_BUFFER_SIZE);
33f54da3 SS	371	return 0;
74a5808b	372	#ifndef OPENSSL_NO_DES
33f54da3	373	}
74a5808b	374	#endif
33f54da3 SS	375	}
	376
	377	ctx = EVP_CIPHER_CTX_new();
	378	if (ctx == NULL)
	379	return 0;
	380
	381	ret = cipher_init(ctx, cipher, engine, key, key_len);
	382	if (!ret)
	383	goto out;
	384
	385	/* Initialize input block */
	386	blocksize = EVP_CIPHER_CTX_block_size(ctx);
	387
	388	if (constant_len > blocksize) {
	389	ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CONSTANT_LENGTH);
	390	ret = 0;
	391	goto out;
	392	}
	393
	394	n_fold(block, blocksize, constant, constant_len);
	395	plainblock = block;
	396	cipherblock = block + EVP_MAX_BLOCK_LENGTH;
	397
	398	for (osize = 0; osize < okey_len; osize += cipherlen) {
	399	int olen;
	400
	401	ret = EVP_EncryptUpdate(ctx, cipherblock, &olen,
	402	plainblock, blocksize);
	403	if (!ret)
	404	goto out;
	405	cipherlen = olen;
	406	ret = EVP_EncryptFinal_ex(ctx, cipherblock, &olen);
	407	if (!ret)
	408	goto out;
	409	if (olen != 0) {
	410	ERR_raise(ERR_LIB_PROV, PROV_R_WRONG_FINAL_BLOCK_LENGTH);
	411	ret = 0;
	412	goto out;
	413	}
	414
	415	/* write cipherblock out */
	416	if (cipherlen > okey_len - osize)
	417	cipherlen = okey_len - osize;
	418	memcpy(okey + osize, cipherblock, cipherlen);
	419
	420	if (okey_len > osize + cipherlen) {
	421	/* we need to reinitialize cipher context per spec */
	422	ret = EVP_CIPHER_CTX_reset(ctx);
	423	if (!ret)
	424	goto out;
	425	ret = cipher_init(ctx, cipher, engine, key, key_len);
	426	if (!ret)
	427	goto out;
	428
	429	/* also swap block offsets so last ciphertext becomes new
	430	* plaintext */
	431	plainblock = cipherblock;
	432	if (cipherblock == block) {
	433	cipherblock += EVP_MAX_BLOCK_LENGTH;
	434	} else {
	435	cipherblock = block;
	436	}
	437	}
	438	}
439
440	#ifndef OPENSSL_NO_DES
441	if (EVP_CIPHER_nid(cipher) == NID_des_ede3_cbc && !des3_no_fixup) {
442	ret = fixup_des3_key(okey);
443	if (!ret) {
444	ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GENERATE_KEY);
445	goto out;
446	}
447	}
448	#endif
449
450	ret = 1;
451
452	out:
453	EVP_CIPHER_CTX_free(ctx);
454	OPENSSL_cleanse(block, EVP_MAX_BLOCK_LENGTH * 2);
455	return ret;
456	}
457