openssl.c

/* Copyright (C) 2009, 2010 Simon Josefsson
 * Copyright (C) 2006, 2007 The Written Word, Inc.  All rights reserved.
 * Copyright (c) 2004-2006, Sara Golemon <sarag@libssh2.org>
 *
 * Author: Simon Josefsson
 *
 * Redistribution and use in source and binary forms,
 * with or without modification, are permitted provided
 * that the following conditions are met:
 *
 *   Redistributions of source code must retain the above
 *   copyright notice, this list of conditions and the
 *   following disclaimer.
 *
 *   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.
 *
 *   Neither the name of the copyright holder nor the names
 *   of any other contributors may be used to endorse or
 *   promote products derived from this software without
 *   specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
 */

#include "libssh2_priv.h"

#ifdef LIBSSH2_OPENSSL /* compile only if we build with openssl */

#include <string.h>
#include "misc.h"

#ifndef EVP_MAX_BLOCK_LENGTH
#define EVP_MAX_BLOCK_LENGTH 32
#endif

int
read_openssh_private_key_from_memory(void **key_ctx, LIBSSH2_SESSION *session,
                                     const char *key_type,
                                     const char *filedata,
                                     size_t filedata_len,
                                     unsigned const char *passphrase);

static unsigned char *
write_bn(unsigned char *buf, const BIGNUM *bn, int bn_bytes)
{
    unsigned char *p = buf;

    /* Left space for bn size which will be written below. */
    p += 4;

    *p = 0;
    BN_bn2bin(bn, p + 1);
    if(!(*(p + 1) & 0x80)) {
        memmove(p, p + 1, --bn_bytes);
    }
    _libssh2_htonu32(p - 4, bn_bytes);  /* Post write bn size. */

    return p + bn_bytes;
}

int
_libssh2_rsa_new(libssh2_rsa_ctx ** rsa,
                 const unsigned char *edata,
                 unsigned long elen,
                 const unsigned char *ndata,
                 unsigned long nlen,
                 const unsigned char *ddata,
                 unsigned long dlen,
                 const unsigned char *pdata,
                 unsigned long plen,
                 const unsigned char *qdata,
                 unsigned long qlen,
                 const unsigned char *e1data,
                 unsigned long e1len,
                 const unsigned char *e2data,
                 unsigned long e2len,
                 const unsigned char *coeffdata, unsigned long coefflen)
{
    BIGNUM * e;
    BIGNUM * n;
    BIGNUM * d = 0;
    BIGNUM * p = 0;
    BIGNUM * q = 0;
    BIGNUM * dmp1 = 0;
    BIGNUM * dmq1 = 0;
    BIGNUM * iqmp = 0;

    e = BN_new();
    BN_bin2bn(edata, elen, e);

    n = BN_new();
    BN_bin2bn(ndata, nlen, n);

    if(ddata) {
        d = BN_new();
        BN_bin2bn(ddata, dlen, d);

        p = BN_new();
        BN_bin2bn(pdata, plen, p);

        q = BN_new();
        BN_bin2bn(qdata, qlen, q);

        dmp1 = BN_new();
        BN_bin2bn(e1data, e1len, dmp1);

        dmq1 = BN_new();
        BN_bin2bn(e2data, e2len, dmq1);

        iqmp = BN_new();
        BN_bin2bn(coeffdata, coefflen, iqmp);
    }

    *rsa = RSA_new();
#ifdef HAVE_OPAQUE_STRUCTS
    RSA_set0_key(*rsa, n, e, d);
#else
    (*rsa)->e = e;
    (*rsa)->n = n;
    (*rsa)->d = d;
#endif

#ifdef HAVE_OPAQUE_STRUCTS
    RSA_set0_factors(*rsa, p, q);
#else
    (*rsa)->p = p;
    (*rsa)->q = q;
#endif

#ifdef HAVE_OPAQUE_STRUCTS
    RSA_set0_crt_params(*rsa, dmp1, dmq1, iqmp);
#else
    (*rsa)->dmp1 = dmp1;
    (*rsa)->dmq1 = dmq1;
    (*rsa)->iqmp = iqmp;
#endif
    return 0;
}

int
_libssh2_rsa_sha1_verify(libssh2_rsa_ctx * rsactx,
                         const unsigned char *sig,
                         unsigned long sig_len,
                         const unsigned char *m, unsigned long m_len)
{
    unsigned char hash[SHA_DIGEST_LENGTH];
    int ret;

    if(_libssh2_sha1(m, m_len, hash))
        return -1; /* failure */
    ret = RSA_verify(NID_sha1, hash, SHA_DIGEST_LENGTH,
                     (unsigned char *) sig, sig_len, rsactx);
    return (ret == 1) ? 0 : -1;
}

#if LIBSSH2_DSA
int
_libssh2_dsa_new(libssh2_dsa_ctx ** dsactx,
                 const unsigned char *p,
                 unsigned long p_len,
                 const unsigned char *q,
                 unsigned long q_len,
                 const unsigned char *g,
                 unsigned long g_len,
                 const unsigned char *y,
                 unsigned long y_len,
                 const unsigned char *x, unsigned long x_len)
{
    BIGNUM * p_bn;
    BIGNUM * q_bn;
    BIGNUM * g_bn;
    BIGNUM * pub_key;
    BIGNUM * priv_key = NULL;

    p_bn = BN_new();
    BN_bin2bn(p, p_len, p_bn);

    q_bn = BN_new();
    BN_bin2bn(q, q_len, q_bn);

    g_bn = BN_new();
    BN_bin2bn(g, g_len, g_bn);

    pub_key = BN_new();
    BN_bin2bn(y, y_len, pub_key);

    if(x_len) {
        priv_key = BN_new();
        BN_bin2bn(x, x_len, priv_key);
    }

    *dsactx = DSA_new();

#ifdef HAVE_OPAQUE_STRUCTS
    DSA_set0_pqg(*dsactx, p_bn, q_bn, g_bn);
#else
    (*dsactx)->p = p_bn;
    (*dsactx)->g = g_bn;
    (*dsactx)->q = q_bn;
#endif

#ifdef HAVE_OPAQUE_STRUCTS
    DSA_set0_key(*dsactx, pub_key, priv_key);
#else
    (*dsactx)->pub_key = pub_key;
    (*dsactx)->priv_key = priv_key;
#endif
    return 0;
}

int
_libssh2_dsa_sha1_verify(libssh2_dsa_ctx * dsactx,
                         const unsigned char *sig,
                         const unsigned char *m, unsigned long m_len)
{
    unsigned char hash[SHA_DIGEST_LENGTH];
    DSA_SIG * dsasig;
    BIGNUM * r;
    BIGNUM * s;
    int ret = -1;

    r = BN_new();
    BN_bin2bn(sig, 20, r);
    s = BN_new();
    BN_bin2bn(sig + 20, 20, s);

    dsasig = DSA_SIG_new();
#ifdef HAVE_OPAQUE_STRUCTS
    DSA_SIG_set0(dsasig, r, s);
#else
    dsasig->r = r;
    dsasig->s = s;
#endif
    if(!_libssh2_sha1(m, m_len, hash))
        /* _libssh2_sha1() succeeded */
        ret = DSA_do_verify(hash, SHA_DIGEST_LENGTH, dsasig, dsactx);

    DSA_SIG_free(dsasig);

    return (ret == 1) ? 0 : -1;
}
#endif /* LIBSSH_DSA */

#if LIBSSH2_ECDSA

/* _libssh2_ecdsa_key_get_curve_type
 *
 * returns key curve type that maps to libssh2_curve_type
 *
 */

libssh2_curve_type
_libssh2_ecdsa_key_get_curve_type(_libssh2_ec_key *key)
{
    const EC_GROUP *group = EC_KEY_get0_group(key);
    return EC_GROUP_get_curve_name(group);
}

/* _libssh2_ecdsa_curve_type_from_name
 *
 * returns 0 for success, key curve type that maps to libssh2_curve_type
 *
 */

int
_libssh2_ecdsa_curve_type_from_name(const char *name, libssh2_curve_type *out_type)
{
    int ret = 0;
    libssh2_curve_type type;

    if(name == NULL || strlen(name) != 19)
        return -1;

    if(strcmp(name, "ecdsa-sha2-nistp256") == 0)
        type = LIBSSH2_EC_CURVE_NISTP256;
    else if(strcmp(name, "ecdsa-sha2-nistp384") == 0)
        type = LIBSSH2_EC_CURVE_NISTP384;
    else if(strcmp(name, "ecdsa-sha2-nistp521") == 0)
        type = LIBSSH2_EC_CURVE_NISTP521;
    else {
        ret = -1;
    }

    if(ret == 0 && out_type) {
        *out_type = type;
    }

    return ret;
}

/* _libssh2_ecdsa_curve_name_with_octal_new
 *
 * Creates a new public key given an octal string, length and type
 *
 */

int
_libssh2_ecdsa_curve_name_with_octal_new(libssh2_ecdsa_ctx ** ec_ctx,
     const unsigned char *k,
     size_t k_len, libssh2_curve_type curve)
{

    int ret = 0;
    const EC_GROUP *ec_group = NULL;
    EC_KEY *ec_key = EC_KEY_new_by_curve_name(curve);
    EC_POINT *point = NULL;

    if(ec_key) {
        ec_group = EC_KEY_get0_group(ec_key);
        point = EC_POINT_new(ec_group);
        ret = EC_POINT_oct2point(ec_group, point, k, k_len, NULL);
        ret = EC_KEY_set_public_key(ec_key, point);

        if(point != NULL)
            EC_POINT_free(point);

        if(ec_ctx != NULL)
            *ec_ctx = ec_key;
    }

    return (ret == 1) ? 0 : -1;
}

#define LIBSSH2_ECDSA_VERIFY(digest_type)                           \
{                                                                   \
    unsigned char hash[SHA##digest_type##_DIGEST_LENGTH];           \
    libssh2_sha##digest_type(m, m_len, hash);                       \
    ret = ECDSA_do_verify(hash, SHA##digest_type##_DIGEST_LENGTH,   \
      ecdsa_sig, ec_key);                                           \
                                                                    \
}

int
_libssh2_ecdsa_verify(libssh2_ecdsa_ctx * ctx,
      const unsigned char *r, size_t r_len,
      const unsigned char *s, size_t s_len,
      const unsigned char *m, size_t m_len)
{
    int ret = 0;
    EC_KEY *ec_key = (EC_KEY*)ctx;
    libssh2_curve_type type = _libssh2_ecdsa_key_get_curve_type(ec_key);

#ifdef HAVE_OPAQUE_STRUCTS
    ECDSA_SIG *ecdsa_sig = ECDSA_SIG_new();
    BIGNUM *pr = BN_new();
    BIGNUM *ps = BN_new();

    BN_bin2bn(r, r_len, pr);
    BN_bin2bn(s, s_len, ps);
    ECDSA_SIG_set0(ecdsa_sig, pr, ps);

#else
    ECDSA_SIG ecdsa_sig_;
    ECDSA_SIG *ecdsa_sig = &ecdsa_sig_;
    ecdsa_sig_.r = BN_new();
    BN_bin2bn(r, r_len, ecdsa_sig_.r);
    ecdsa_sig_.s = BN_new();
    BN_bin2bn(s, s_len, ecdsa_sig_.s);
#endif

    if(type == LIBSSH2_EC_CURVE_NISTP256) {
        LIBSSH2_ECDSA_VERIFY(256);
    }
    else if(type == LIBSSH2_EC_CURVE_NISTP384) {
        LIBSSH2_ECDSA_VERIFY(384);
    }
    else if(type == LIBSSH2_EC_CURVE_NISTP521) {
        LIBSSH2_ECDSA_VERIFY(512);
    }

#ifdef HAVE_OPAQUE_STRUCTS
    if(ecdsa_sig)
        ECDSA_SIG_free(ecdsa_sig);
#else
    BN_clear_free(ecdsa_sig_.s);
    BN_clear_free(ecdsa_sig_.r);
#endif

    return (ret == 1) ? 0 : -1;
}

#endif /* LIBSSH2_ECDSA */

int
_libssh2_cipher_init(_libssh2_cipher_ctx * h,
                     _libssh2_cipher_type(algo),
                     unsigned char *iv, unsigned char *secret, int encrypt)
{
#ifdef HAVE_OPAQUE_STRUCTS
    *h = EVP_CIPHER_CTX_new();
    return !EVP_CipherInit(*h, algo(), secret, iv, encrypt);
#else
    EVP_CIPHER_CTX_init(h);
    return !EVP_CipherInit(h, algo(), secret, iv, encrypt);
#endif
}

int
_libssh2_cipher_crypt(_libssh2_cipher_ctx * ctx,
                      _libssh2_cipher_type(algo),
                      int encrypt, unsigned char *block, size_t blocksize)
{
    unsigned char buf[EVP_MAX_BLOCK_LENGTH];
    int ret;
    (void) algo;
    (void) encrypt;

#ifdef HAVE_OPAQUE_STRUCTS
    ret = EVP_Cipher(*ctx, buf, block, blocksize);
#else
    ret = EVP_Cipher(ctx, buf, block, blocksize);
#endif
    if(ret == 1) {
        memcpy(block, buf, blocksize);
    }
    return ret == 1 ? 0 : 1;
}

#if LIBSSH2_AES_CTR && !defined(HAVE_EVP_AES_128_CTR)

#include <openssl/aes.h>
#include <openssl/evp.h>

typedef struct
{
    AES_KEY       key;
    EVP_CIPHER_CTX *aes_ctx;
    unsigned char ctr[AES_BLOCK_SIZE];
} aes_ctr_ctx;

static int
aes_ctr_init(EVP_CIPHER_CTX *ctx, const unsigned char *key,
             const unsigned char *iv, int enc) /* init key */
{
    /*
     * variable "c" is leaked from this scope, but is later freed
     * in aes_ctr_cleanup
     */
    aes_ctr_ctx *c;
    const EVP_CIPHER *aes_cipher;
    (void) enc;

    switch(EVP_CIPHER_CTX_key_length(ctx)) {
    case 16:
        aes_cipher = EVP_aes_128_ecb();
        break;
    case 24:
        aes_cipher = EVP_aes_192_ecb();
        break;
    case 32:
        aes_cipher = EVP_aes_256_ecb();
        break;
    default:
        return 0;
    }

    c = malloc(sizeof(*c));
    if(c == NULL)
        return 0;

#ifdef HAVE_OPAQUE_STRUCTS
    c->aes_ctx = EVP_CIPHER_CTX_new();
#else
    c->aes_ctx = malloc(sizeof(EVP_CIPHER_CTX));
#endif
    if(c->aes_ctx == NULL) {
        free(c);
        return 0;
    }

    if(EVP_EncryptInit(c->aes_ctx, aes_cipher, key, NULL) != 1) {
#ifdef HAVE_OPAQUE_STRUCTS
        EVP_CIPHER_CTX_free(c->aes_ctx);
#else
        free(c->aes_ctx);
#endif
        free(c);
        return 0;
    }

    EVP_CIPHER_CTX_set_padding(c->aes_ctx, 0);

    memcpy(c->ctr, iv, AES_BLOCK_SIZE);

    EVP_CIPHER_CTX_set_app_data(ctx, c);

    return 1;
}

static int
aes_ctr_do_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
                  const unsigned char *in,
                  size_t inl) /* encrypt/decrypt data */
{
    aes_ctr_ctx *c = EVP_CIPHER_CTX_get_app_data(ctx);
    unsigned char b1[AES_BLOCK_SIZE];
    int outlen = 0;

    if(inl != 16) /* libssh2 only ever encrypt one block */
        return 0;

    if(c == NULL) {
        return 0;
    }

/*
  To encrypt a packet P=P1||P2||...||Pn (where P1, P2, ..., Pn are each
  blocks of length L), the encryptor first encrypts <X> with <cipher>
  to obtain a block B1.  The block B1 is then XORed with P1 to generate
  the ciphertext block C1.  The counter X is then incremented
*/

    if(EVP_EncryptUpdate(c->aes_ctx, b1, &outlen, c->ctr, AES_BLOCK_SIZE) != 1) {
        return 0;
    }

    _libssh2_xor_data(out, in, b1, AES_BLOCK_SIZE);
    _libssh2_aes_ctr_increment(c->ctr, AES_BLOCK_SIZE);

    return 1;
}

static int
aes_ctr_cleanup(EVP_CIPHER_CTX *ctx) /* cleanup ctx */
{
    aes_ctr_ctx *c = EVP_CIPHER_CTX_get_app_data(ctx);

    if(c == NULL) {
        return 1;
    }

    if(c->aes_ctx != NULL) {
#ifdef HAVE_OPAQUE_STRUCTS
        EVP_CIPHER_CTX_free(c->aes_ctx);
#else
        _libssh2_cipher_dtor(c->aes_ctx);
        free(c->aes_ctx);
#endif
    }

    free(c);

    return 1;
}

static const EVP_CIPHER *
make_ctr_evp (size_t keylen, EVP_CIPHER **aes_ctr_cipher, int type)
{
#ifdef HAVE_OPAQUE_STRUCTS
    *aes_ctr_cipher = EVP_CIPHER_meth_new(type, 16, keylen);
    if(*aes_ctr_cipher) {
        EVP_CIPHER_meth_set_iv_length(*aes_ctr_cipher, 16);
        EVP_CIPHER_meth_set_init(*aes_ctr_cipher, aes_ctr_init);
        EVP_CIPHER_meth_set_do_cipher(*aes_ctr_cipher, aes_ctr_do_cipher);
        EVP_CIPHER_meth_set_cleanup(*aes_ctr_cipher, aes_ctr_cleanup);
    }
#else
    (*aes_ctr_cipher)->nid = type;
    (*aes_ctr_cipher)->block_size = 16;
    (*aes_ctr_cipher)->key_len = keylen;
    (*aes_ctr_cipher)->iv_len = 16;
    (*aes_ctr_cipher)->init = aes_ctr_init;
    (*aes_ctr_cipher)->do_cipher = aes_ctr_do_cipher;
    (*aes_ctr_cipher)->cleanup = aes_ctr_cleanup;
#endif

    return *aes_ctr_cipher;
}

const EVP_CIPHER *
_libssh2_EVP_aes_128_ctr(void)
{
#ifdef HAVE_OPAQUE_STRUCTS
    static EVP_CIPHER * aes_ctr_cipher;
    return !aes_ctr_cipher ?
        make_ctr_evp(16, &aes_ctr_cipher, NID_aes_128_ctr) : aes_ctr_cipher;
#else
    static EVP_CIPHER aes_ctr_cipher;
    static EVP_CIPHER * aes_ctr_cipher_ptr = &aes_ctr_cipher;
    return !aes_ctr_cipher.key_len ?
        make_ctr_evp(16, &aes_ctr_cipher_ptr, 0) : &aes_ctr_cipher;
#endif
}

const EVP_CIPHER *
_libssh2_EVP_aes_192_ctr(void)
{
#ifdef HAVE_OPAQUE_STRUCTS
    static EVP_CIPHER * aes_ctr_cipher;
    return !aes_ctr_cipher ?
        make_ctr_evp(24, &aes_ctr_cipher, NID_aes_192_ctr) : aes_ctr_cipher;
#else
    static EVP_CIPHER aes_ctr_cipher;
    static EVP_CIPHER * aes_ctr_cipher_ptr = &aes_ctr_cipher;
    return !aes_ctr_cipher.key_len ?
        make_ctr_evp(24, &aes_ctr_cipher_ptr, 0) : &aes_ctr_cipher;
#endif
}

const EVP_CIPHER *
_libssh2_EVP_aes_256_ctr(void)
{
#ifdef HAVE_OPAQUE_STRUCTS
    static EVP_CIPHER * aes_ctr_cipher;
    return !aes_ctr_cipher ?
        make_ctr_evp(32, &aes_ctr_cipher, NID_aes_256_ctr) : aes_ctr_cipher;
#else
    static EVP_CIPHER aes_ctr_cipher;
    static EVP_CIPHER * aes_ctr_cipher_ptr = &aes_ctr_cipher;
    return !aes_ctr_cipher.key_len ?
        make_ctr_evp(32, &aes_ctr_cipher_ptr, 0) : &aes_ctr_cipher;
#endif
}

#endif /* LIBSSH2_AES_CTR */

#ifndef HAVE_EVP_AES_128_CTR
static EVP_CIPHER * aes_128_ctr_cipher = NULL;
static EVP_CIPHER * aes_192_ctr_cipher = NULL;
static EVP_CIPHER * aes_256_ctr_cipher = NULL;
#endif

void _libssh2_openssl_crypto_init(void)
{
#if OPENSSL_VERSION_NUMBER >= 0x10100000L
#ifndef OPENSSL_NO_ENGINE
    ENGINE_load_builtin_engines();
    ENGINE_register_all_complete();
#endif
#else
    OpenSSL_add_all_algorithms();
    OpenSSL_add_all_ciphers();
#ifndef OPENSSL_NO_ENGINE
    ENGINE_load_builtin_engines();
    ENGINE_register_all_complete();
#endif
#endif
#ifndef HAVE_EVP_AES_128_CTR
    aes_128_ctr_cipher = (EVP_CIPHER *)_libssh2_EVP_aes_128_ctr();
    aes_192_ctr_cipher = (EVP_CIPHER *)_libssh2_EVP_aes_192_ctr();
    aes_256_ctr_cipher = (EVP_CIPHER *)_libssh2_EVP_aes_256_ctr();
#endif
}

void _libssh2_openssl_crypto_exit(void)
{
#ifndef HAVE_EVP_AES_128_CTR
#ifdef HAVE_OPAQUE_STRUCTS
    if(aes_128_ctr_cipher) {
        EVP_CIPHER_meth_free(aes_128_ctr_cipher);
    }

    if(aes_192_ctr_cipher) {
        EVP_CIPHER_meth_free(aes_192_ctr_cipher);
    }

    if(aes_256_ctr_cipher) {
        EVP_CIPHER_meth_free(aes_256_ctr_cipher);
    }
#endif

    aes_128_ctr_cipher = NULL;
    aes_192_ctr_cipher = NULL;
    aes_256_ctr_cipher = NULL;
#endif
}

/* TODO: Optionally call a passphrase callback specified by the
 * calling program
 */
static int
passphrase_cb(char *buf, int size, int rwflag, char *passphrase)
{
    int passphrase_len = strlen(passphrase);
    (void) rwflag;

    if(passphrase_len > (size - 1)) {
        passphrase_len = size - 1;
    }
    memcpy(buf, passphrase, passphrase_len);
    buf[passphrase_len] = '\0';

    return passphrase_len;
}

typedef void * (*pem_read_bio_func)(BIO *, void **, pem_password_cb *,
                                    void *u);

static int
read_private_key_from_memory(void **key_ctx,
                             pem_read_bio_func read_private_key,
                             const char *filedata,
                             size_t filedata_len,
                             unsigned const char *passphrase)
{
    BIO * bp;

    *key_ctx = NULL;

    bp = BIO_new_mem_buf((char *)filedata, filedata_len);
    if(!bp) {
        return -1;
    }
    *key_ctx = read_private_key(bp, NULL, (pem_password_cb *) passphrase_cb,
                                (void *) passphrase);

    BIO_free(bp);
    return (*key_ctx) ? 0 : -1;
}



static int
read_private_key_from_file(void **key_ctx,
                           pem_read_bio_func read_private_key,
                           const char *filename,
                           unsigned const char *passphrase)
{
    BIO * bp;

    *key_ctx = NULL;

    bp = BIO_new_file(filename, "r");
    if(!bp) {
        return -1;
    }

    *key_ctx = read_private_key(bp, NULL, (pem_password_cb *) passphrase_cb,
                                (void *) passphrase);

    BIO_free(bp);
    return (*key_ctx) ? 0 : -1;
}

int
_libssh2_rsa_new_private_frommemory(libssh2_rsa_ctx ** rsa,
                                    LIBSSH2_SESSION * session,
                                    const char *filedata, size_t filedata_len,
                                    unsigned const char *passphrase)
{
    int rc;

    pem_read_bio_func read_rsa =
        (pem_read_bio_func) &PEM_read_bio_RSAPrivateKey;
    (void) session;

    _libssh2_init_if_needed();

    rc = read_private_key_from_memory((void **) rsa, read_rsa,
                                      filedata, filedata_len, passphrase);

    if(rc) {
        rc = read_openssh_private_key_from_memory((void**)rsa, session,
                        "ssh-rsa", filedata, filedata_len, passphrase);
    }

return rc;
}

static unsigned char *
gen_publickey_from_rsa(LIBSSH2_SESSION *session, RSA *rsa,
                       size_t *key_len)
{
    int            e_bytes, n_bytes;
    unsigned long  len;
    unsigned char *key;
    unsigned char *p;
    const BIGNUM * e;
    const BIGNUM * n;
#ifdef HAVE_OPAQUE_STRUCTS
    RSA_get0_key(rsa, &n, &e, NULL);
#else
    e = rsa->e;
    n = rsa->n;
#endif
    e_bytes = BN_num_bytes(e) + 1;
    n_bytes = BN_num_bytes(n) + 1;

    /* Key form is "ssh-rsa" + e + n. */
    len = 4 + 7 + 4 + e_bytes + 4 + n_bytes;

    key = LIBSSH2_ALLOC(session, len);
    if(key == NULL) {
        return NULL;
    }

    /* Process key encoding. */
    p = key;

    _libssh2_htonu32(p, 7);  /* Key type. */
    p += 4;
    memcpy(p, "ssh-rsa", 7);
    p += 7;

    p = write_bn(p, e, e_bytes);
    p = write_bn(p, n, n_bytes);

    *key_len = (size_t)(p - key);
    return key;
}

static int
gen_publickey_from_rsa_evp(LIBSSH2_SESSION *session,
                           unsigned char **method,
                           size_t *method_len,
                           unsigned char **pubkeydata,
                           size_t *pubkeydata_len,
                           EVP_PKEY *pk)
{
    RSA*           rsa = NULL;
    unsigned char *key;
    unsigned char *method_buf = NULL;
    size_t  key_len;

    _libssh2_debug(session,
                   LIBSSH2_TRACE_AUTH,
                   "Computing public key from RSA private key envelop");

    rsa = EVP_PKEY_get1_RSA(pk);
    if(rsa == NULL) {
        /* Assume memory allocation error... what else could it be ? */
        goto __alloc_error;
    }

    method_buf = LIBSSH2_ALLOC(session, 7);  /* ssh-rsa. */
    if(method_buf == NULL) {
        goto __alloc_error;
    }

    key = gen_publickey_from_rsa(session, rsa, &key_len);
    if(key == NULL) {
        goto __alloc_error;
    }
    RSA_free(rsa);

    memcpy(method_buf, "ssh-rsa", 7);
    *method         = method_buf;
    *method_len     = 7;
    *pubkeydata     = key;
    *pubkeydata_len = key_len;
    return 0;

  __alloc_error:
    if(rsa != NULL) {
        RSA_free(rsa);
    }
    if(method_buf != NULL) {
        LIBSSH2_FREE(session, method_buf);
    }

    return _libssh2_error(session,
                          LIBSSH2_ERROR_ALLOC,
                          "Unable to allocate memory for private key data");
}

int
_libssh2_rsa_new_additional_parameters(RSA *rsa)
{
    BN_CTX *ctx = NULL;
    BIGNUM *aux = NULL;
    BIGNUM *dmp1 = NULL;
    BIGNUM *dmq1 = NULL;
    const BIGNUM *p = NULL;
    const BIGNUM *q = NULL;
    const BIGNUM *d = NULL;
    int rc = 0;

#ifdef HAVE_OPAQUE_STRUCTS
    RSA_get0_key(rsa, NULL, NULL, &d);
    RSA_get0_factors(rsa, &p, &q);
#else
    d = (*rsa).d;
    p = (*rsa).p;
    q = (*rsa).q;
#endif

    if((ctx = BN_CTX_new()) == NULL)
        return -1;

    if((aux = BN_new()) == NULL) {
        rc = -1;
        goto out;
    }

    if((dmp1 = BN_new()) == NULL) {
        rc = -1;
        goto out;
    }

    if((dmq1 = BN_new()) == NULL) {
        rc = -1;
        goto out;
    }

    if((BN_sub(aux, q, BN_value_one()) == 0) ||
        (BN_mod(dmq1, d, aux, ctx) == 0) ||
        (BN_sub(aux, p, BN_value_one()) == 0) ||
        (BN_mod(dmp1, d, aux, ctx) == 0)) {
        rc = -1;
        goto out;
    }

#ifdef HAVE_OPAQUE_STRUCTS
    RSA_set0_crt_params(rsa, dmp1, dmq1, NULL);
#else
    (*rsa).dmp1 = dmp1;
    (*rsa).dmq1 = dmq1;
#endif

out:
    if(aux)
        BN_clear_free(aux);
    BN_CTX_free(ctx);

    if(rc != 0) {
        if(dmp1)
            BN_clear_free(dmp1);
        if(dmq1)
            BN_clear_free(dmq1);
    }

    return rc;
}

int
gen_publickey_from_rsa_openssh_priv_data(LIBSSH2_SESSION *session,
                                         struct string_buf *decrypted,
                                         unsigned char **method,
                                         size_t *method_len,
                                         unsigned char **pubkeydata,
                                         size_t *pubkeydata_len,
                                         libssh2_rsa_ctx **rsa_ctx)
{
    int rc = 0;
    int nlen, elen, dlen, plen, qlen, coefflen;
    unsigned char *n, *e, *d, *p, *q, *coeff, *comment;
    int commentlen;
    RSA *rsa = NULL;

    _libssh2_debug(session,
                   LIBSSH2_TRACE_AUTH,
                   "Computing RSA keys from private key data");

    // public key data
    if((nlen = _libssh2_get_bignum_bytes(decrypted, &n)) <= 0) {
        _libssh2_error(session, LIBSSH2_ERROR_PROTO,
                       "RSA no n");
        return -1;
    }

    if((elen = _libssh2_get_bignum_bytes(decrypted, &e)) <= 0) {
        _libssh2_error(session, LIBSSH2_ERROR_PROTO,
                       "RSA no e");
        return -1;
    }

    // private key data
    if((dlen = _libssh2_get_bignum_bytes(decrypted, &d)) <= 0) {
        _libssh2_error(session, LIBSSH2_ERROR_PROTO,
                       "RSA no d");
        return -1;
    }

    if((coefflen = _libssh2_get_bignum_bytes(decrypted, &coeff)) <= 0) {
        _libssh2_error(session, LIBSSH2_ERROR_PROTO,
                       "RSA no coeff");
        return -1;
    }

    if((plen = _libssh2_get_bignum_bytes(decrypted, &p)) <= 0) {
        _libssh2_error(session, LIBSSH2_ERROR_PROTO,
                       "RSA no p");
        return -1;
    }

    if((qlen = _libssh2_get_bignum_bytes(decrypted, &q)) <= 0) {
        _libssh2_error(session, LIBSSH2_ERROR_PROTO,
                       "RSA no q");
        return -1;
    }

    if((commentlen = _libssh2_get_c_string(decrypted, &comment)) < 0) {
        _libssh2_error(session, LIBSSH2_ERROR_PROTO,
                       "RSA no comment");