openssl.c

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/*
 * openssl.c
 *      Wrapper for OpenSSL library.
 *
 * Copyright (c) 2001 Marko Kreen
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS 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 AUTHOR OR 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.
 *
 * contrib/pgcrypto/openssl.c
 */

#include "postgres.h"

#include "px.h"

#include <openssl/evp.h>
#include <openssl/blowfish.h>
#include <openssl/cast.h>
#include <openssl/des.h>
#include <openssl/rand.h>
#include <openssl/err.h>

/*
 * Max lengths we might want to handle.
 */
#define MAX_KEY     (512/8)
#define MAX_IV      (128/8)

/*
 * Compatibility with OpenSSL 0.9.6
 *
 * It needs AES and newer DES and digest API.
 */
#if OPENSSL_VERSION_NUMBER >= 0x00907000L

/*
 * Nothing needed for OpenSSL 0.9.7+
 */

#include <openssl/aes.h>
#else                           /* old OPENSSL */

/*
 * Emulate OpenSSL AES.
 */

#include "rijndael.c"

#define AES_ENCRYPT 1
#define AES_DECRYPT 0
#define AES_KEY     rijndael_ctx

static int
AES_set_encrypt_key(const uint8 *key, int kbits, AES_KEY *ctx)
{
    aes_set_key(ctx, key, kbits, 1);
    return 0;
}

static int
AES_set_decrypt_key(const uint8 *key, int kbits, AES_KEY *ctx)
{
    aes_set_key(ctx, key, kbits, 0);
    return 0;
}

static void
AES_ecb_encrypt(const uint8 *src, uint8 *dst, AES_KEY *ctx, int enc)
{
    memcpy(dst, src, 16);
    if (enc)
        aes_ecb_encrypt(ctx, dst, 16);
    else
        aes_ecb_decrypt(ctx, dst, 16);
}

static void
AES_cbc_encrypt(const uint8 *src, uint8 *dst, int len, AES_KEY *ctx, uint8 *iv, int enc)
{
    memcpy(dst, src, len);
    if (enc)
    {
        aes_cbc_encrypt(ctx, iv, dst, len);
        memcpy(iv, dst + len - 16, 16);
    }
    else
    {
        aes_cbc_decrypt(ctx, iv, dst, len);
        memcpy(iv, src + len - 16, 16);
    }
}

/*
 * Emulate DES_* API
 */

#define DES_key_schedule des_key_schedule
#define DES_cblock des_cblock
#define DES_set_key(k, ks) \
        des_set_key((k), *(ks))
#define DES_ecb_encrypt(i, o, k, e) \
        des_ecb_encrypt((i), (o), *(k), (e))
#define DES_ncbc_encrypt(i, o, l, k, iv, e) \
        des_ncbc_encrypt((i), (o), (l), *(k), (iv), (e))
#define DES_ecb3_encrypt(i, o, k1, k2, k3, e) \
        des_ecb3_encrypt((des_cblock *)(i), (des_cblock *)(o), \
                *(k1), *(k2), *(k3), (e))
#define DES_ede3_cbc_encrypt(i, o, l, k1, k2, k3, iv, e) \
        des_ede3_cbc_encrypt((i), (o), \
                (l), *(k1), *(k2), *(k3), (iv), (e))

/*
 * Emulate newer digest API.
 */

static void
EVP_MD_CTX_init(EVP_MD_CTX *ctx)
{
    memset(ctx, 0, sizeof(*ctx));
}

static int
EVP_MD_CTX_cleanup(EVP_MD_CTX *ctx)
{
    memset(ctx, 0, sizeof(*ctx));
    return 1;
}

static int
EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *md, void *engine)
{
    EVP_DigestInit(ctx, md);
    return 1;
}

static int
EVP_DigestFinal_ex(EVP_MD_CTX *ctx, unsigned char *res, unsigned int *len)
{
    EVP_DigestFinal(ctx, res, len);
    return 1;
}
#endif   /* old OpenSSL */

/*
 * Provide SHA2 for older OpenSSL < 0.9.8
 */
#if OPENSSL_VERSION_NUMBER < 0x00908000L

#include "sha2.c"
#include "internal-sha2.c"

typedef void (*init_f) (PX_MD *md);

static int
compat_find_digest(const char *name, PX_MD **res)
{
    init_f      init = NULL;

    if (pg_strcasecmp(name, "sha224") == 0)
        init = init_sha224;
    else if (pg_strcasecmp(name, "sha256") == 0)
        init = init_sha256;
    else if (pg_strcasecmp(name, "sha384") == 0)
        init = init_sha384;
    else if (pg_strcasecmp(name, "sha512") == 0)
        init = init_sha512;
    else
        return PXE_NO_HASH;

    *res = px_alloc(sizeof(PX_MD));
    init(*res);
    return 0;
}
#else
#define compat_find_digest(name, res)  (PXE_NO_HASH)
#endif

/*
 * Hashes
 */

typedef struct OSSLDigest
{
    const EVP_MD *algo;
    EVP_MD_CTX  ctx;
} OSSLDigest;

static unsigned
digest_result_size(PX_MD *h)
{
    OSSLDigest *digest = (OSSLDigest *) h->p.ptr;

    return EVP_MD_CTX_size(&digest->ctx);
}

static unsigned
digest_block_size(PX_MD *h)
{
    OSSLDigest *digest = (OSSLDigest *) h->p.ptr;

    return EVP_MD_CTX_block_size(&digest->ctx);
}

static void
digest_reset(PX_MD *h)
{
    OSSLDigest *digest = (OSSLDigest *) h->p.ptr;

    EVP_DigestInit_ex(&digest->ctx, digest->algo, NULL);
}

static void
digest_update(PX_MD *h, const uint8 *data, unsigned dlen)
{
    OSSLDigest *digest = (OSSLDigest *) h->p.ptr;

    EVP_DigestUpdate(&digest->ctx, data, dlen);
}

static void
digest_finish(PX_MD *h, uint8 *dst)
{
    OSSLDigest *digest = (OSSLDigest *) h->p.ptr;

    EVP_DigestFinal_ex(&digest->ctx, dst, NULL);
}

static void
digest_free(PX_MD *h)
{
    OSSLDigest *digest = (OSSLDigest *) h->p.ptr;

    EVP_MD_CTX_cleanup(&digest->ctx);

    px_free(digest);
    px_free(h);
}

static int  px_openssl_initialized = 0;

/* PUBLIC functions */

int
px_find_digest(const char *name, PX_MD **res)
{
    const EVP_MD *md;
    PX_MD      *h;
    OSSLDigest *digest;

    if (!px_openssl_initialized)
    {
        px_openssl_initialized = 1;
        OpenSSL_add_all_algorithms();
    }

    md = EVP_get_digestbyname(name);
    if (md == NULL)
        return compat_find_digest(name, res);

    digest = px_alloc(sizeof(*digest));
    digest->algo = md;

    EVP_MD_CTX_init(&digest->ctx);
    if (EVP_DigestInit_ex(&digest->ctx, digest->algo, NULL) == 0)
        return -1;

    h = px_alloc(sizeof(*h));
    h->result_size = digest_result_size;
    h->block_size = digest_block_size;
    h->reset = digest_reset;
    h->update = digest_update;
    h->finish = digest_finish;
    h->free = digest_free;
    h->p.ptr = (void *) digest;

    *res = h;
    return 0;
}

/*
 * Ciphers
 *
 * The problem with OpenSSL is that the EVP* family
 * of functions does not allow enough flexibility
 * and forces some of the parameters (keylen,
 * padding) to SSL defaults.
 *
 * So need to manage ciphers ourselves.
 */

struct ossl_cipher
{
    int         (*init) (PX_Cipher *c, const uint8 *key, unsigned klen, const uint8 *iv);
    int         (*encrypt) (PX_Cipher *c, const uint8 *data, unsigned dlen, uint8 *res);
    int         (*decrypt) (PX_Cipher *c, const uint8 *data, unsigned dlen, uint8 *res);

    int         block_size;
    int         max_key_size;
    int         stream_cipher;
};

typedef struct
{
    union
    {
        struct
        {
            BF_KEY      key;
            int         num;
        }           bf;
        struct
        {
            DES_key_schedule key_schedule;
        }           des;
        struct
        {
            DES_key_schedule k1,
                        k2,
                        k3;
        }           des3;
        CAST_KEY    cast_key;
        AES_KEY     aes_key;
    }           u;
    uint8       key[MAX_KEY];
    uint8       iv[MAX_IV];
    unsigned    klen;
    unsigned    init;
    const struct ossl_cipher *ciph;
} ossldata;

/* generic */

static unsigned
gen_ossl_block_size(PX_Cipher *c)
{
    ossldata   *od = (ossldata *) c->ptr;

    return od->ciph->block_size;
}

static unsigned
gen_ossl_key_size(PX_Cipher *c)
{
    ossldata   *od = (ossldata *) c->ptr;

    return od->ciph->max_key_size;
}

static unsigned
gen_ossl_iv_size(PX_Cipher *c)
{
    unsigned    ivlen;
    ossldata   *od = (ossldata *) c->ptr;

    ivlen = od->ciph->block_size;
    return ivlen;
}

static void
gen_ossl_free(PX_Cipher *c)
{
    ossldata   *od = (ossldata *) c->ptr;

    memset(od, 0, sizeof(*od));
    px_free(od);
    px_free(c);
}

/* Blowfish */

/*
 * Check if strong crypto is supported. Some openssl installations
 * support only short keys and unfortunately BF_set_key does not return any
 * error value. This function tests if is possible to use strong key.
 */
static int
bf_check_supported_key_len(void)
{
    static const uint8 key[56] = {
        0xf0, 0xe1, 0xd2, 0xc3, 0xb4, 0xa5, 0x96, 0x87, 0x78, 0x69,
        0x5a, 0x4b, 0x3c, 0x2d, 0x1e, 0x0f, 0x00, 0x11, 0x22, 0x33,
        0x44, 0x55, 0x66, 0x77, 0x04, 0x68, 0x91, 0x04, 0xc2, 0xfd,
        0x3b, 0x2f, 0x58, 0x40, 0x23, 0x64, 0x1a, 0xba, 0x61, 0x76,
        0x1f, 0x1f, 0x1f, 0x1f, 0x0e, 0x0e, 0x0e, 0x0e, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff
    };

    static const uint8 data[8] = {0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10};
    static const uint8 res[8] = {0xc0, 0x45, 0x04, 0x01, 0x2e, 0x4e, 0x1f, 0x53};
    static uint8 out[8];

    BF_KEY      bf_key;

    /* encrypt with 448bits key and verify output */
    BF_set_key(&bf_key, 56, key);
    BF_ecb_encrypt(data, out, &bf_key, BF_ENCRYPT);

    if (memcmp(out, res, 8) != 0)
        return 0;               /* Output does not match -> strong cipher is
                                 * not supported */
    return 1;
}

static int
bf_init(PX_Cipher *c, const uint8 *key, unsigned klen, const uint8 *iv)
{
    ossldata   *od = c->ptr;
    static int  bf_is_strong = -1;

    /*
     * Test if key len is supported. BF_set_key silently cut large keys and it
     * could be be a problem when user transfer crypted data from one server
     * to another.
     */

    if (bf_is_strong == -1)
        bf_is_strong = bf_check_supported_key_len();

    if (!bf_is_strong && klen > 16)
        return PXE_KEY_TOO_BIG;

    /* Key len is supported. We can use it. */
    BF_set_key(&od->u.bf.key, klen, key);
    if (iv)
        memcpy(od->iv, iv, BF_BLOCK);
    else
        memset(od->iv, 0, BF_BLOCK);
    od->u.bf.num = 0;
    return 0;
}

static int
bf_ecb_encrypt(PX_Cipher *c, const uint8 *data, unsigned dlen, uint8 *res)
{
    unsigned    bs = gen_ossl_block_size(c);
    unsigned    i;
    ossldata   *od = c->ptr;

    for (i = 0; i < dlen / bs; i++)
        BF_ecb_encrypt(data + i * bs, res + i * bs, &od->u.bf.key, BF_ENCRYPT);
    return 0;
}

static int
bf_ecb_decrypt(PX_Cipher *c, const uint8 *data, unsigned dlen, uint8 *res)
{
    unsigned    bs = gen_ossl_block_size(c),
                i;
    ossldata   *od = c->ptr;

    for (i = 0; i < dlen / bs; i++)
        BF_ecb_encrypt(data + i * bs, res + i * bs, &od->u.bf.key, BF_DECRYPT);
    return 0;
}

static int
bf_cbc_encrypt(PX_Cipher *c, const uint8 *data, unsigned dlen, uint8 *res)
{
    ossldata   *od = c->ptr;

    BF_cbc_encrypt(data, res, dlen, &od->u.bf.key, od->iv, BF_ENCRYPT);
    return 0;
}

static int
bf_cbc_decrypt(PX_Cipher *c, const uint8 *data, unsigned dlen, uint8 *res)
{
    ossldata   *od = c->ptr;

    BF_cbc_encrypt(data, res, dlen, &od->u.bf.key, od->iv, BF_DECRYPT);
    return 0;
}

static int
bf_cfb64_encrypt(PX_Cipher *c, const uint8 *data, unsigned dlen, uint8 *res)
{
    ossldata   *od = c->ptr;

    BF_cfb64_encrypt(data, res, dlen, &od->u.bf.key, od->iv,
                     &od->u.bf.num, BF_ENCRYPT);
    return 0;
}

static int
bf_cfb64_decrypt(PX_Cipher *c, const uint8 *data, unsigned dlen, uint8 *res)
{
    ossldata   *od = c->ptr;

    BF_cfb64_encrypt(data, res, dlen, &od->u.bf.key, od->iv,
                     &od->u.bf.num, BF_DECRYPT);
    return 0;
}

/* DES */

static int
ossl_des_init(PX_Cipher *c, const uint8 *key, unsigned klen, const uint8 *iv)
{
    ossldata   *od = c->ptr;
    DES_cblock  xkey;

    memset(&xkey, 0, sizeof(xkey));
    memcpy(&xkey, key, klen > 8 ? 8 : klen);
    DES_set_key(&xkey, &od->u.des.key_schedule);
    memset(&xkey, 0, sizeof(xkey));

    if (iv)
        memcpy(od->iv, iv, 8);
    else
        memset(od->iv, 0, 8);
    return 0;
}

static int
ossl_des_ecb_encrypt(PX_Cipher *c, const uint8 *data, unsigned dlen,
                     uint8 *res)
{
    unsigned    bs = gen_ossl_block_size(c);
    unsigned    i;
    ossldata   *od = c->ptr;

    for (i = 0; i < dlen / bs; i++)
        DES_ecb_encrypt((DES_cblock *) (data + i * bs),
                        (DES_cblock *) (res + i * bs),
                        &od->u.des.key_schedule, 1);
    return 0;
}

static int
ossl_des_ecb_decrypt(PX_Cipher *c, const uint8 *data, unsigned dlen,
                     uint8 *res)
{
    unsigned    bs = gen_ossl_block_size(c);
    unsigned    i;
    ossldata   *od = c->ptr;

    for (i = 0; i < dlen / bs; i++)
        DES_ecb_encrypt((DES_cblock *) (data + i * bs),
                        (DES_cblock *) (res + i * bs),
                        &od->u.des.key_schedule, 0);
    return 0;
}

static int
ossl_des_cbc_encrypt(PX_Cipher *c, const uint8 *data, unsigned dlen,
                     uint8 *res)
{
    ossldata   *od = c->ptr;

    DES_ncbc_encrypt(data, res, dlen, &od->u.des.key_schedule,
                     (DES_cblock *) od->iv, 1);
    return 0;
}

static int
ossl_des_cbc_decrypt(PX_Cipher *c, const uint8 *data, unsigned dlen,
                     uint8 *res)
{
    ossldata   *od = c->ptr;

    DES_ncbc_encrypt(data, res, dlen, &od->u.des.key_schedule,
                     (DES_cblock *) od->iv, 0);
    return 0;
}

/* DES3 */

static int
ossl_des3_init(PX_Cipher *c, const uint8 *key, unsigned klen, const uint8 *iv)
{
    ossldata   *od = c->ptr;
    DES_cblock  xkey1,
                xkey2,
                xkey3;

    memset(&xkey1, 0, sizeof(xkey1));
    memset(&xkey2, 0, sizeof(xkey2));
    memset(&xkey3, 0, sizeof(xkey3));
    memcpy(&xkey1, key, klen > 8 ? 8 : klen);
    if (klen > 8)
        memcpy(&xkey2, key + 8, (klen - 8) > 8 ? 8 : (klen - 8));
    if (klen > 16)
        memcpy(&xkey3, key + 16, (klen - 16) > 8 ? 8 : (klen - 16));

    DES_set_key(&xkey1, &od->u.des3.k1);
    DES_set_key(&xkey2, &od->u.des3.k2);
    DES_set_key(&xkey3, &od->u.des3.k3);
    memset(&xkey1, 0, sizeof(xkey1));
    memset(&xkey2, 0, sizeof(xkey2));
    memset(&xkey3, 0, sizeof(xkey3));

    if (iv)
        memcpy(od->iv, iv, 8);
    else
        memset(od->iv, 0, 8);
    return 0;
}

static int
ossl_des3_ecb_encrypt(PX_Cipher *c, const uint8 *data, unsigned dlen,
                      uint8 *res)
{
    unsigned    bs = gen_ossl_block_size(c);
    unsigned    i;
    ossldata   *od = c->ptr;

    for (i = 0; i < dlen / bs; i++)
        DES_ecb3_encrypt((void *) (data + i * bs), (void *) (res + i * bs),
                         &od->u.des3.k1, &od->u.des3.k2, &od->u.des3.k3, 1);
    return 0;
}

static int
ossl_des3_ecb_decrypt(PX_Cipher *c, const uint8 *data, unsigned dlen,
                      uint8 *res)
{
    unsigned    bs = gen_ossl_block_size(c);
    unsigned    i;
    ossldata   *od = c->ptr;

    for (i = 0; i < dlen / bs; i++)
        DES_ecb3_encrypt((void *) (data + i * bs), (void *) (res + i * bs),
                         &od->u.des3.k1, &od->u.des3.k2, &od->u.des3.k3, 0);
    return 0;
}

static int
ossl_des3_cbc_encrypt(PX_Cipher *c, const uint8 *data, unsigned dlen,
                      uint8 *res)
{
    ossldata   *od = c->ptr;

    DES_ede3_cbc_encrypt(data, res, dlen,
                         &od->u.des3.k1, &od->u.des3.k2, &od->u.des3.k3,
                         (DES_cblock *) od->iv, 1);
    return 0;
}

static int
ossl_des3_cbc_decrypt(PX_Cipher *c, const uint8 *data, unsigned dlen,
                      uint8 *res)
{
    ossldata   *od = c->ptr;

    DES_ede3_cbc_encrypt(data, res, dlen,
                         &od->u.des3.k1, &od->u.des3.k2, &od->u.des3.k3,
                         (DES_cblock *) od->iv, 0);
    return 0;
}

/* CAST5 */

static int
ossl_cast_init(PX_Cipher *c, const uint8 *key, unsigned klen, const uint8 *iv)
{
    ossldata   *od = c->ptr;
    unsigned    bs = gen_ossl_block_size(c);

    CAST_set_key(&od->u.cast_key, klen, key);
    if (iv)
        memcpy(od->iv, iv, bs);
    else
        memset(od->iv, 0, bs);
    return 0;
}

static int
ossl_cast_ecb_encrypt(PX_Cipher *c, const uint8 *data, unsigned dlen, uint8 *res)
{
    unsigned    bs = gen_ossl_block_size(c);
    ossldata   *od = c->ptr;
    const uint8 *end = data + dlen - bs;

    for (; data <= end; data += bs, res += bs)
        CAST_ecb_encrypt(data, res, &od->u.cast_key, CAST_ENCRYPT);
    return 0;
}

static int
ossl_cast_ecb_decrypt(PX_Cipher *c, const uint8 *data, unsigned dlen, uint8 *res)
{
    unsigned    bs = gen_ossl_block_size(c);
    ossldata   *od = c->ptr;
    const uint8 *end = data + dlen - bs;

    for (; data <= end; data += bs, res += bs)
        CAST_ecb_encrypt(data, res, &od->u.cast_key, CAST_DECRYPT);
    return 0;
}

static int
ossl_cast_cbc_encrypt(PX_Cipher *c, const uint8 *data, unsigned dlen, uint8 *res)
{
    ossldata   *od = c->ptr;

    CAST_cbc_encrypt(data, res, dlen, &od->u.cast_key, od->iv, CAST_ENCRYPT);
    return 0;
}

static int
ossl_cast_cbc_decrypt(PX_Cipher *c, const uint8 *data, unsigned dlen, uint8 *res)
{
    ossldata   *od = c->ptr;

    CAST_cbc_encrypt(data, res, dlen, &od->u.cast_key, od->iv, CAST_DECRYPT);
    return 0;
}

/* AES */

static int
ossl_aes_init(PX_Cipher *c, const uint8 *key, unsigned klen, const uint8 *iv)
{
    ossldata   *od = c->ptr;
    unsigned    bs = gen_ossl_block_size(c);

    if (klen <= 128 / 8)
        od->klen = 128 / 8;
    else if (klen <= 192 / 8)
        od->klen = 192 / 8;
    else if (klen <= 256 / 8)
        od->klen = 256 / 8;
    else
        return PXE_KEY_TOO_BIG;

    memcpy(od->key, key, klen);

    if (iv)
        memcpy(od->iv, iv, bs);
    else
        memset(od->iv, 0, bs);
    return 0;
}

static int
ossl_aes_key_init(ossldata *od, int type)
{
    int         err;

    /*
     * Strong key support could be missing on some openssl installations. We
     * must check return value from set key function.
     */
    if (type == AES_ENCRYPT)
        err = AES_set_encrypt_key(od->key, od->klen * 8, &od->u.aes_key);
    else
        err = AES_set_decrypt_key(od->key, od->klen * 8, &od->u.aes_key);

    if (err == 0)
    {
        od->init = 1;
        return 0;
    }
    od->init = 0;
    return PXE_KEY_TOO_BIG;
}

static int
ossl_aes_ecb_encrypt(PX_Cipher *c, const uint8 *data, unsigned dlen,
                     uint8 *res)
{
    unsigned    bs = gen_ossl_block_size(c);
    ossldata   *od = c->ptr;
    const uint8 *end = data + dlen - bs;
    int         err;

    if (!od->init)
        if ((err = ossl_aes_key_init(od, AES_ENCRYPT)) != 0)
            return err;

    for (; data <= end; data += bs, res += bs)
        AES_ecb_encrypt(data, res, &od->u.aes_key, AES_ENCRYPT);
    return 0;
}

static int
ossl_aes_ecb_decrypt(PX_Cipher *c, const uint8 *data, unsigned dlen,
                     uint8 *res)
{
    unsigned    bs = gen_ossl_block_size(c);
    ossldata   *od = c->ptr;
    const uint8 *end = data + dlen - bs;
    int         err;

    if (!od->init)
        if ((err = ossl_aes_key_init(od, AES_DECRYPT)) != 0)
            return err;

    for (; data <= end; data += bs, res += bs)
        AES_ecb_encrypt(data, res, &od->u.aes_key, AES_DECRYPT);
    return 0;
}

static int
ossl_aes_cbc_encrypt(PX_Cipher *c, const uint8 *data, unsigned dlen,
                     uint8 *res)
{
    ossldata   *od = c->ptr;
    int         err;

    if (!od->init)
        if ((err = ossl_aes_key_init(od, AES_ENCRYPT)) != 0)
            return err;

    AES_cbc_encrypt(data, res, dlen, &od->u.aes_key, od->iv, AES_ENCRYPT);
    return 0;
}

static int
ossl_aes_cbc_decrypt(PX_Cipher *c, const uint8 *data, unsigned dlen,
                     uint8 *res)
{
    ossldata   *od = c->ptr;
    int         err;

    if (!od->init)
        if ((err = ossl_aes_key_init(od, AES_DECRYPT)) != 0)
            return err;

    AES_cbc_encrypt(data, res, dlen, &od->u.aes_key, od->iv, AES_DECRYPT);
    return 0;
}

/*
 * aliases
 */

static PX_Alias ossl_aliases[] = {
    {"bf", "bf-cbc"},
    {"blowfish", "bf-cbc"},
    {"blowfish-cbc", "bf-cbc"},
    {"blowfish-ecb", "bf-ecb"},
    {"blowfish-cfb", "bf-cfb"},
    {"des", "des-cbc"},
    {"3des", "des3-cbc"},
    {"3des-ecb", "des3-ecb"},
    {"3des-cbc", "des3-cbc"},
    {"cast5", "cast5-cbc"},
    {"aes", "aes-cbc"},
    {"rijndael", "aes-cbc"},
    {"rijndael-cbc", "aes-cbc"},
    {"rijndael-ecb", "aes-ecb"},
    {NULL}
};

static const struct ossl_cipher ossl_bf_cbc = {
    bf_init, bf_cbc_encrypt, bf_cbc_decrypt,
    64 / 8, 448 / 8, 0
};

static const struct ossl_cipher ossl_bf_ecb = {
    bf_init, bf_ecb_encrypt, bf_ecb_decrypt,
    64 / 8, 448 / 8, 0
};

static const struct ossl_cipher ossl_bf_cfb = {
    bf_init, bf_cfb64_encrypt, bf_cfb64_decrypt,
    64 / 8, 448 / 8, 1
};

static const struct ossl_cipher ossl_des_ecb = {
    ossl_des_init, ossl_des_ecb_encrypt, ossl_des_ecb_decrypt,
    64 / 8, 64 / 8, 0
};

static const struct ossl_cipher ossl_des_cbc = {
    ossl_des_init, ossl_des_cbc_encrypt, ossl_des_cbc_decrypt,
    64 / 8, 64 / 8, 0
};

static const struct ossl_cipher ossl_des3_ecb = {
    ossl_des3_init, ossl_des3_ecb_encrypt, ossl_des3_ecb_decrypt,
    64 / 8, 192 / 8, 0
};

static const struct ossl_cipher ossl_des3_cbc = {
    ossl_des3_init, ossl_des3_cbc_encrypt, ossl_des3_cbc_decrypt,
    64 / 8, 192 / 8, 0
};

static const struct ossl_cipher ossl_cast_ecb = {
    ossl_cast_init, ossl_cast_ecb_encrypt, ossl_cast_ecb_decrypt,
    64 / 8, 128 / 8, 0
};

static const struct ossl_cipher ossl_cast_cbc = {
    ossl_cast_init, ossl_cast_cbc_encrypt, ossl_cast_cbc_decrypt,
    64 / 8, 128 / 8, 0
};

static const struct ossl_cipher ossl_aes_ecb = {
    ossl_aes_init, ossl_aes_ecb_encrypt, ossl_aes_ecb_decrypt,
    128 / 8, 256 / 8, 0
};

static const struct ossl_cipher ossl_aes_cbc = {
    ossl_aes_init, ossl_aes_cbc_encrypt, ossl_aes_cbc_decrypt,
    128 / 8, 256 / 8, 0
};

/*
 * Special handlers
 */
struct ossl_cipher_lookup
{
    const char *name;
    const struct ossl_cipher *ciph;
};

static const struct ossl_cipher_lookup ossl_cipher_types[] = {
    {"bf-cbc", &ossl_bf_cbc},
    {"bf-ecb", &ossl_bf_ecb},
    {"bf-cfb", &ossl_bf_cfb},
    {"des-ecb", &ossl_des_ecb},
    {"des-cbc", &ossl_des_cbc},
    {"des3-ecb", &ossl_des3_ecb},
    {"des3-cbc", &ossl_des3_cbc},
    {"cast5-ecb", &ossl_cast_ecb},
    {"cast5-cbc", &ossl_cast_cbc},
    {"aes-ecb", &ossl_aes_ecb},
    {"aes-cbc", &ossl_aes_cbc},
    {NULL}
};

/* PUBLIC functions */

int
px_find_cipher(const char *name, PX_Cipher **res)
{
    const struct ossl_cipher_lookup *i;
    PX_Cipher  *c = NULL;
    ossldata   *od;

    name = px_resolve_alias(ossl_aliases, name);
    for (i = ossl_cipher_types; i->name; i++)
        if (strcmp(i->name, name) == 0)
            break;
    if (i->name == NULL)
        return PXE_NO_CIPHER;

    od = px_alloc(sizeof(*od));
    memset(od, 0, sizeof(*od));
    od->ciph = i->ciph;

    c = px_alloc(sizeof(*c));
    c->block_size = gen_ossl_block_size;
    c->key_size = gen_ossl_key_size;
    c->iv_size = gen_ossl_iv_size;
    c->free = gen_ossl_free;
    c->init = od->ciph->init;
    c->encrypt = od->ciph->encrypt;
    c->decrypt = od->ciph->decrypt;
    c->ptr = od;

    *res = c;
    return 0;
}


static int  openssl_random_init = 0;

/*
 * OpenSSL random should re-feeded occasionally. From /dev/urandom
 * preferably.
 */
static void
init_openssl_rand(void)
{
    if (RAND_get_rand_method() == NULL)
        RAND_set_rand_method(RAND_SSLeay());
    openssl_random_init = 1;
}

int
px_get_random_bytes(uint8 *dst, unsigned count)
{
    int         res;

    if (!openssl_random_init)
        init_openssl_rand();

    res = RAND_bytes(dst, count);
    if (res == 1)
        return count;

    return PXE_OSSL_RAND_ERROR;
}

int
px_get_pseudo_random_bytes(uint8 *dst, unsigned count)
{
    int         res;

    if (!openssl_random_init)
        init_openssl_rand();

    res = RAND_pseudo_bytes(dst, count);
    if (res == 0 || res == 1)
        return count;

    return PXE_OSSL_RAND_ERROR;
}

int
px_add_entropy(const uint8 *data, unsigned count)
{
    /*
     * estimate 0 bits
     */
    RAND_add(data, count, 0);
    return 0;
}