/src/libssh/src/dh_crypto.c

Source (jump to first uncovered line)
/*
 * This file is part of the SSH Library
 *
 * Copyright (c) 2019 by Simo Sorce - Red Hat, Inc.
 *
 * The SSH Library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at your
 * option) any later version.
 *
 * The SSH Library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with the SSH Library; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

#include "config.h"
#include "libssh/session.h"
#include "libssh/dh.h"
#include "libssh/buffer.h"
#include "libssh/ssh2.h"
#include "libssh/pki.h"
#include "libssh/bignum.h"

#include "openssl/crypto.h"
#include "openssl/dh.h"
#include "libcrypto-compat.h"
#if OPENSSL_VERSION_NUMBER >= 0x30000000L
#include <openssl/evp.h>
#include <openssl/params.h>
#include <openssl/core_names.h>
#include <openssl/param_build.h>
#include <openssl/err.h>
#endif /* OPENSSL_VERSION_NUMBER */

extern bignum ssh_dh_generator;
extern bignum ssh_dh_group1;
extern bignum ssh_dh_group14;
extern bignum ssh_dh_group16;
extern bignum ssh_dh_group18;

struct dh_ctx {
#if OPENSSL_VERSION_NUMBER < 0x30000000L
    DH *keypair[2];
#else
    EVP_PKEY *keypair[2];
#endif /* OPENSSL_VERSION_NUMBER */
};

void ssh_dh_debug_crypto(struct ssh_crypto_struct *c)
{
#ifdef DEBUG_CRYPTO
#if OPENSSL_VERSION_NUMBER < 0x30000000L
    const_bignum x = NULL, y = NULL, e = NULL, f = NULL;
#else
    bignum x = NULL, y = NULL, e = NULL, f = NULL;
#endif /* OPENSSL_VERSION_NUMBER */

    ssh_dh_keypair_get_keys(c->dh_ctx, DH_CLIENT_KEYPAIR, &x, &e);
    ssh_dh_keypair_get_keys(c->dh_ctx, DH_SERVER_KEYPAIR, &y, &f);
    ssh_print_bignum("x", x);
    ssh_print_bignum("y", y);
    ssh_print_bignum("e", e);
    ssh_print_bignum("f", f);
#if OPENSSL_VERSION_NUMBER >= 0x30000000L
    bignum_safe_free(x);
    bignum_safe_free(y);
    bignum_safe_free(e);
    bignum_safe_free(f);
#endif /* OPENSSL_VERSION_NUMBER */

    ssh_log_hexdump("Session server cookie", c->server_kex.cookie, 16);
    ssh_log_hexdump("Session client cookie", c->client_kex.cookie, 16);
    ssh_print_bignum("k", c->shared_secret);

#else
    (void)c; /* UNUSED_PARAM */
#endif /* DEBUG_CRYPTO */
}

#if OPENSSL_VERSION_NUMBER < 0x30000000L
int ssh_dh_keypair_get_keys(struct dh_ctx *ctx, int peer,
                            const_bignum *priv, const_bignum *pub)
{
    if (((peer != DH_CLIENT_KEYPAIR) && (peer != DH_SERVER_KEYPAIR)) ||
        ((priv == NULL) && (pub == NULL)) || (ctx == NULL) ||
        (ctx->keypair[peer] == NULL)) {
        return SSH_ERROR;
    }

    DH_get0_key(ctx->keypair[peer], pub, priv);

    if (priv && (*priv == NULL || bignum_num_bits(*priv) == 0)) {
        return SSH_ERROR;
    }
    if (pub && (*pub == NULL || bignum_num_bits(*pub) == 0)) {
        return SSH_ERROR;
    }

    return SSH_OK;
}

#else
/* If set *priv and *pub should be initialized
 * to NULL before calling this function*/
int ssh_dh_keypair_get_keys(struct dh_ctx *ctx, int peer,
                            bignum *priv, bignum *pub)
{
    int rc;
    if (((peer != DH_CLIENT_KEYPAIR) && (peer != DH_SERVER_KEYPAIR)) ||
        ((priv == NULL) && (pub == NULL)) || (ctx == NULL) ||
        (ctx->keypair[peer] == NULL)) {
        return SSH_ERROR;
    }

    if (priv) {
        rc = EVP_PKEY_get_bn_param(ctx->keypair[peer],
                                   OSSL_PKEY_PARAM_PRIV_KEY,
                                   priv);
        if (rc != 1) {
            return SSH_ERROR;
        }
    }
    if (pub) {
        rc = EVP_PKEY_get_bn_param(ctx->keypair[peer],
                                   OSSL_PKEY_PARAM_PUB_KEY,
                                   pub);
        if (rc != 1) {
            return SSH_ERROR;
        }
    }
    if (priv && (*priv == NULL || bignum_num_bits(*priv) == 0)) {
        if (pub && (*pub != NULL && bignum_num_bits(*pub) != 0)) {
            bignum_safe_free(*pub);
            *pub = NULL;
        }
        return SSH_ERROR;
    }
    if (pub && (*pub == NULL || bignum_num_bits(*pub) == 0)) {
        if (priv) {
            bignum_safe_free(*priv);
            *priv = NULL;
        }
        return SSH_ERROR;
    }

    return SSH_OK;
}
#endif /* OPENSSL_VERSION_NUMBER */

int ssh_dh_keypair_set_keys(struct dh_ctx *ctx, int peer,
                            bignum priv, bignum pub)
{
#if OPENSSL_VERSION_NUMBER >= 0x30000000L
    int rc;
    OSSL_PARAM *params = NULL, *out_params = NULL, *merged_params = NULL;
    OSSL_PARAM_BLD *param_bld = NULL;
    EVP_PKEY_CTX *evp_ctx = NULL;
#endif /* OPENSSL_VERSION_NUMBER */

    if (((peer != DH_CLIENT_KEYPAIR) && (peer != DH_SERVER_KEYPAIR)) ||
        ((priv == NULL) && (pub == NULL)) || (ctx == NULL) ||
        (ctx->keypair[peer] == NULL)) {
        return SSH_ERROR;
    }

#if OPENSSL_VERSION_NUMBER < 0x30000000L
    (void)DH_set0_key(ctx->keypair[peer], pub, priv);

    return SSH_OK;
#else
    rc = EVP_PKEY_todata(ctx->keypair[peer], EVP_PKEY_KEYPAIR, &out_params);
    if (rc != 1) {
        return SSH_ERROR;
    }

    param_bld = OSSL_PARAM_BLD_new();
    if (param_bld == NULL) {
        rc = SSH_ERROR;
        goto out;
    }

    evp_ctx = EVP_PKEY_CTX_new_from_pkey(NULL, ctx->keypair[peer], NULL);
    if (evp_ctx == NULL) {
        rc = SSH_ERROR;
        goto out;
    }

    rc = EVP_PKEY_fromdata_init(evp_ctx);
    if (rc != 1) {
        rc = SSH_ERROR;
        goto out;
    }

    if (priv) {
        rc = OSSL_PARAM_BLD_push_BN(param_bld, OSSL_PKEY_PARAM_PRIV_KEY, priv);
        if (rc != 1) {
            rc = SSH_ERROR;
            goto out;
        }
    }
    if (pub) {
        rc = OSSL_PARAM_BLD_push_BN(param_bld, OSSL_PKEY_PARAM_PUB_KEY, pub);
        if (rc != 1) {
            rc = SSH_ERROR;
            goto out;
        }
    }

    params = OSSL_PARAM_BLD_to_param(param_bld);
    if (params == NULL) {
        rc = SSH_ERROR;
        goto out;
    }
    OSSL_PARAM_BLD_free(param_bld);

    merged_params = OSSL_PARAM_merge(out_params, params);
    if (merged_params == NULL) {
        rc = SSH_ERROR;
        goto out;
    }

    rc = EVP_PKEY_fromdata(evp_ctx,
                           &(ctx->keypair[peer]),
                           EVP_PKEY_PUBLIC_KEY,
                           merged_params);
    if (rc != 1) {
        rc = SSH_ERROR;
        goto out;
    }

    rc = SSH_OK;
out:
    bignum_safe_free(priv);
    bignum_safe_free(pub);
    EVP_PKEY_CTX_free(evp_ctx);
    OSSL_PARAM_free(out_params);
    OSSL_PARAM_free(params);
    OSSL_PARAM_free(merged_params);

    return rc;
#endif /* OPENSSL_VERSION_NUMBER */
}

#if OPENSSL_VERSION_NUMBER < 0x30000000L
int ssh_dh_get_parameters(struct dh_ctx *ctx,
                          const_bignum *modulus, const_bignum *generator)
{
    if (ctx == NULL || ctx->keypair[0] == NULL) {
        return SSH_ERROR;
    }
    DH_get0_pqg(ctx->keypair[0], modulus, NULL, generator);
    return SSH_OK;
}
#else
int ssh_dh_get_parameters(struct dh_ctx *ctx,
                          bignum *modulus, bignum *generator)
{
    int rc;

    if (ctx == NULL || ctx->keypair[0] == NULL) {
        return SSH_ERROR;
    }

    rc = EVP_PKEY_get_bn_param(ctx->keypair[0], OSSL_PKEY_PARAM_FFC_P, (BIGNUM**)modulus);
    if (rc != 1) {
        return SSH_ERROR;
    }
    rc = EVP_PKEY_get_bn_param(ctx->keypair[0], OSSL_PKEY_PARAM_FFC_G, (BIGNUM**)generator);
    if (rc != 1) {
        bignum_safe_free(*modulus);
        return SSH_ERROR;
    }

    return SSH_OK;
}
#endif /* OPENSSL_VERSION_NUMBER */

int ssh_dh_set_parameters(struct dh_ctx *ctx,
                          const bignum modulus, const bignum generator)
{
    size_t i;
    int rc;
#if OPENSSL_VERSION_NUMBER >= 0x30000000L
    OSSL_PARAM *params = NULL;
    OSSL_PARAM_BLD *param_bld = NULL;
    EVP_PKEY_CTX *evp_ctx = NULL;
#endif /* OPENSSL_VERSION_NUMBER */

    if ((ctx == NULL) || (modulus == NULL) || (generator == NULL)) {
        return SSH_ERROR;
    }

#if OPENSSL_VERSION_NUMBER >= 0x30000000L
    evp_ctx = EVP_PKEY_CTX_new_from_name(NULL, "DHX", NULL);
#endif

    for (i = 0; i < 2; i++) {
#if OPENSSL_VERSION_NUMBER < 0x30000000L
        bignum p = NULL;
        bignum g = NULL;

        /* when setting modulus or generator,
         * make sure to invalidate existing keys */
        DH_free(ctx->keypair[i]);
        ctx->keypair[i] = DH_new();
        if (ctx->keypair[i] == NULL) {
            rc = SSH_ERROR;
            goto done;
        }

        p = BN_dup(modulus);
        g = BN_dup(generator);
        rc = DH_set0_pqg(ctx->keypair[i], p, NULL, g);
        if (rc != 1) {
            BN_free(p);
            BN_free(g);
            rc = SSH_ERROR;
            goto done;
        }
#else
        param_bld = OSSL_PARAM_BLD_new();

        if (param_bld == NULL) {
            rc = SSH_ERROR;
            goto done;
        }

        rc = OSSL_PARAM_BLD_push_BN(param_bld, OSSL_PKEY_PARAM_FFC_P, modulus);
        if (rc != 1) {
            rc = SSH_ERROR;
            goto done;
        }
        rc = OSSL_PARAM_BLD_push_BN(param_bld, OSSL_PKEY_PARAM_FFC_G, generator);
        if (rc != 1) {
            rc = SSH_ERROR;
            goto done;
        }
        params = OSSL_PARAM_BLD_to_param(param_bld);
        if (params == NULL) {
            OSSL_PARAM_BLD_free(param_bld);
            rc = SSH_ERROR;
            goto done;
        }
        OSSL_PARAM_BLD_free(param_bld);

        rc = EVP_PKEY_fromdata_init(evp_ctx);
        if (rc != 1) {
            OSSL_PARAM_free(params);
            rc = SSH_ERROR;
            goto done;
        }

        /* make sure to invalidate existing keys */
        EVP_PKEY_free(ctx->keypair[i]);
        ctx->keypair[i] = NULL;

        rc = EVP_PKEY_fromdata(evp_ctx,
                               &(ctx->keypair[i]),
                               EVP_PKEY_KEY_PARAMETERS,
                               params);
        if (rc != 1) {
            OSSL_PARAM_free(params);
            rc = SSH_ERROR;
            goto done;
        }

        OSSL_PARAM_free(params);
#endif /* OPENSSL_VERSION_NUMBER */
    }

    rc = SSH_OK;
#if OPENSSL_VERSION_NUMBER < 0x30000000L
done:
    if (rc != SSH_OK) {
        DH_free(ctx->keypair[0]);
        DH_free(ctx->keypair[1]);
    }
#else
done:
    EVP_PKEY_CTX_free(evp_ctx);

    if (rc != SSH_OK) {
        EVP_PKEY_free(ctx->keypair[0]);
        EVP_PKEY_free(ctx->keypair[1]);
    }
#endif /* OPENSSL_VERSION_NUMBER */
    if (rc != SSH_OK) {
        ctx->keypair[0] = NULL;
        ctx->keypair[1] = NULL;
    }

    return rc;
}

/**
 * @internal
 * @brief allocate and initialize ephemeral values used in dh kex
 */
int ssh_dh_init_common(struct ssh_crypto_struct *crypto)
{
    struct dh_ctx *ctx = NULL;
    int rc;

    ctx = calloc(1, sizeof(*ctx));
    if (ctx == NULL) {
        return SSH_ERROR;
    }
    crypto->dh_ctx = ctx;

    switch (crypto->kex_type) {
    case SSH_KEX_DH_GROUP1_SHA1:
        rc = ssh_dh_set_parameters(ctx, ssh_dh_group1, ssh_dh_generator);
        break;
    case SSH_KEX_DH_GROUP14_SHA1:
    case SSH_KEX_DH_GROUP14_SHA256:
        rc = ssh_dh_set_parameters(ctx, ssh_dh_group14, ssh_dh_generator);
        break;
    case SSH_KEX_DH_GROUP16_SHA512:
        rc = ssh_dh_set_parameters(ctx, ssh_dh_group16, ssh_dh_generator);
        break;
    case SSH_KEX_DH_GROUP18_SHA512:
        rc = ssh_dh_set_parameters(ctx, ssh_dh_group18, ssh_dh_generator);
        break;
    default:
        rc = SSH_OK;
        break;
    }

    if (rc != SSH_OK) {
        ssh_dh_cleanup(crypto);
    }
    return rc;
}

void ssh_dh_cleanup(struct ssh_crypto_struct *crypto)
{
    if (crypto->dh_ctx != NULL) {
#if OPENSSL_VERSION_NUMBER < 0x30000000L
        DH_free(crypto->dh_ctx->keypair[0]);
        DH_free(crypto->dh_ctx->keypair[1]);
#else
        EVP_PKEY_free(crypto->dh_ctx->keypair[0]);
        EVP_PKEY_free(crypto->dh_ctx->keypair[1]);
#endif /* OPENSSL_VERSION_NUMBER */
        free(crypto->dh_ctx);
        crypto->dh_ctx = NULL;
    }
}

/** @internal
 * @brief generates a secret DH parameter of at least DH_SECURITY_BITS
 *        security as well as the corresponding public key.
 *
 * @param[out] params a dh_ctx that will hold the new keys.
 * @param peer Select either client or server key storage. Valid values are:
 *        DH_CLIENT_KEYPAIR or DH_SERVER_KEYPAIR
 *
 * @return SSH_OK on success, SSH_ERROR on error
 */
int ssh_dh_keypair_gen_keys(struct dh_ctx *dh_ctx, int peer)
{
    int rc;
#if OPENSSL_VERSION_NUMBER >= 0x30000000L
    EVP_PKEY_CTX *evp_ctx = NULL;
#endif

    if ((dh_ctx == NULL) || (dh_ctx->keypair[peer] == NULL)) {
        return SSH_ERROR;
    }

#if OPENSSL_VERSION_NUMBER < 0x30000000L
    rc = DH_generate_key(dh_ctx->keypair[peer]);
    if (rc != 1) {
        return SSH_ERROR;
    }
#else
    evp_ctx = EVP_PKEY_CTX_new_from_pkey(NULL, dh_ctx->keypair[peer], NULL);
    if (evp_ctx == NULL) {
        return SSH_ERROR;
    }

    rc = EVP_PKEY_keygen_init(evp_ctx);
    if (rc != 1) {
        EVP_PKEY_CTX_free(evp_ctx);
        return SSH_ERROR;
    }

    rc = EVP_PKEY_generate(evp_ctx, &(dh_ctx->keypair[peer]));
    if (rc != 1) {
        EVP_PKEY_CTX_free(evp_ctx);
        SSH_LOG(SSH_LOG_TRACE,
                "Failed to generate DH: %s",
                ERR_error_string(ERR_get_error(), NULL));
        return SSH_ERROR;
    }

    EVP_PKEY_CTX_free(evp_ctx);
#endif /* OPENSSL_VERSION_NUMBER */

    return SSH_OK;
}

/** @internal
 * @brief generates a shared secret between the local peer and the remote
 *        peer. The local peer must have been initialized using either the
 *        ssh_dh_keypair_gen_keys() function or by seetting manually both
 *        the private and public keys. The remote peer only needs to have
 *        the remote's peer public key set.
 * @param[in] local peer identifier (DH_CLIENT_KEYPAIR or DH_SERVER_KEYPAIR)
 * @param[in] remote peer identifier (DH_CLIENT_KEYPAIR or DH_SERVER_KEYPAIR)
 * @param[out] dest a new bignum with the shared secret value is returned.
 * @return SSH_OK on success, SSH_ERROR on error
 */
int ssh_dh_compute_shared_secret(struct dh_ctx *dh_ctx, int local, int remote,
                                 bignum *dest)
{
    unsigned char *kstring = NULL;
    int rc;
#if OPENSSL_VERSION_NUMBER < 0x30000000L
    const_bignum pub_key = NULL;
    int klen;
#else
    size_t klen;
    EVP_PKEY_CTX *evp_ctx = NULL;
#endif /* OPENSSL_VERSION_NUMBER */

    if ((dh_ctx == NULL) ||
        (dh_ctx->keypair[local] == NULL) ||
        (dh_ctx->keypair[remote] == NULL)) {
        return SSH_ERROR;
    }

#if OPENSSL_VERSION_NUMBER < 0x30000000L
    kstring = malloc(DH_size(dh_ctx->keypair[local]));
    if (kstring == NULL) {
        rc = SSH_ERROR;
        goto done;
    }

    rc = ssh_dh_keypair_get_keys(dh_ctx, remote, NULL, &pub_key);
    if (rc != SSH_OK) {
        rc = SSH_ERROR;
        goto done;
    }

    klen = DH_compute_key(kstring, pub_key, dh_ctx->keypair[local]);
    if (klen == -1) {
        rc = SSH_ERROR;
        goto done;
    }
#else
    evp_ctx = EVP_PKEY_CTX_new_from_pkey(NULL, dh_ctx->keypair[local], NULL);

    rc = EVP_PKEY_derive_init(evp_ctx);
    if (rc != 1) {
        rc = SSH_ERROR;
        goto done;
    }

    rc = EVP_PKEY_derive_set_peer(evp_ctx, dh_ctx->keypair[remote]);
    if (rc != 1) {
        SSH_LOG(SSH_LOG_TRACE,
                "Failed to set peer key: %s",
                ERR_error_string(ERR_get_error(), NULL));
        rc = SSH_ERROR;
        goto done;
    }

    /* getting the size of the secret */
    rc = EVP_PKEY_derive(evp_ctx, kstring, &klen);
    if (rc != 1) {
        rc = SSH_ERROR;
        goto done;
    }

    kstring = malloc(klen);
    if (kstring == NULL) {
        rc = SSH_ERROR;
        goto done;
    }

    rc = EVP_PKEY_derive(evp_ctx, kstring, &klen);
    if (rc != 1) {
        rc = SSH_ERROR;
        goto done;
    }
#endif /* OPENSSL_VERSION_NUMBER */

    *dest = BN_bin2bn(kstring, (int)klen, NULL);
    if (*dest == NULL) {
        rc = SSH_ERROR;
        goto done;
    }

    rc = SSH_OK;
done:
#if OPENSSL_VERSION_NUMBER >= 0x30000000L
    EVP_PKEY_CTX_free(evp_ctx);
#endif
    free(kstring);
    return rc;
}

Coverage Report

Created: 2025-07-01 06:48

Line	Count	Source (jump to first uncovered line)
1		/*
2		* This file is part of the SSH Library
3		*
4		* Copyright (c) 2019 by Simo Sorce - Red Hat, Inc.
5		*
6		* The SSH Library is free software; you can redistribute it and/or modify
7		* it under the terms of the GNU Lesser General Public License as published by
8		* the Free Software Foundation; either version 2.1 of the License, or (at your
9		* option) any later version.
10		*
11		* The SSH Library is distributed in the hope that it will be useful, but
12		* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13		* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
14		* License for more details.
15		*
16		* You should have received a copy of the GNU Lesser General Public License
17		* along with the SSH Library; see the file COPYING. If not, write to
18		* the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
19		* MA 02111-1307, USA.
20		*/
21
22		#include "config.h"
23		#include "libssh/session.h"
24		#include "libssh/dh.h"
25		#include "libssh/buffer.h"
26		#include "libssh/ssh2.h"
27		#include "libssh/pki.h"
28		#include "libssh/bignum.h"
29
30		#include "openssl/crypto.h"
31		#include "openssl/dh.h"
32		#include "libcrypto-compat.h"
33		#if OPENSSL_VERSION_NUMBER >= 0x30000000L
34		#include <openssl/evp.h>
35		#include <openssl/params.h>
36		#include <openssl/core_names.h>
37		#include <openssl/param_build.h>
38		#include <openssl/err.h>
39		#endif /* OPENSSL_VERSION_NUMBER */
40
41		extern bignum ssh_dh_generator;
42		extern bignum ssh_dh_group1;
43		extern bignum ssh_dh_group14;
44		extern bignum ssh_dh_group16;
45		extern bignum ssh_dh_group18;
46
47		struct dh_ctx {
48		#if OPENSSL_VERSION_NUMBER < 0x30000000L
49		DH *keypair[2];
50		#else
51		EVP_PKEY *keypair[2];
52		#endif /* OPENSSL_VERSION_NUMBER */
53		};
54
55		void ssh_dh_debug_crypto(struct ssh_crypto_struct *c)
56	0	{
57		#ifdef DEBUG_CRYPTO
58		#if OPENSSL_VERSION_NUMBER < 0x30000000L
59		const_bignum x = NULL, y = NULL, e = NULL, f = NULL;
60		#else
61		bignum x = NULL, y = NULL, e = NULL, f = NULL;
62		#endif /* OPENSSL_VERSION_NUMBER */
63
64		ssh_dh_keypair_get_keys(c->dh_ctx, DH_CLIENT_KEYPAIR, &x, &e);
65		ssh_dh_keypair_get_keys(c->dh_ctx, DH_SERVER_KEYPAIR, &y, &f);
66		ssh_print_bignum("x", x);
67		ssh_print_bignum("y", y);
68		ssh_print_bignum("e", e);
69		ssh_print_bignum("f", f);
70		#if OPENSSL_VERSION_NUMBER >= 0x30000000L
71		bignum_safe_free(x);
72		bignum_safe_free(y);
73		bignum_safe_free(e);
74		bignum_safe_free(f);
75		#endif /* OPENSSL_VERSION_NUMBER */
76
77		ssh_log_hexdump("Session server cookie", c->server_kex.cookie, 16);
78		ssh_log_hexdump("Session client cookie", c->client_kex.cookie, 16);
79		ssh_print_bignum("k", c->shared_secret);
80
81		#else
82	0	(void)c; /* UNUSED_PARAM */
83	0	#endif /* DEBUG_CRYPTO */
84	0	}
85
86		#if OPENSSL_VERSION_NUMBER < 0x30000000L
87		int ssh_dh_keypair_get_keys(struct dh_ctx *ctx, int peer,
88		const_bignum priv, const_bignum pub)
89	0	{
90	0	if (((peer != DH_CLIENT_KEYPAIR) && (peer != DH_SERVER_KEYPAIR)) \|\|
91	0	((priv == NULL) && (pub == NULL)) \|\| (ctx == NULL) \|\|
92	0	(ctx->keypair[peer] == NULL)) {
93	0	return SSH_ERROR;
94	0	}
95
96	0	DH_get0_key(ctx->keypair[peer], pub, priv);
97
98	0	if (priv && (priv == NULL \|\| bignum_num_bits(priv) == 0)) {
99	0	return SSH_ERROR;
100	0	}
101	0	if (pub && (pub == NULL \|\| bignum_num_bits(pub) == 0)) {
102	0	return SSH_ERROR;
103	0	}
104
105	0	return SSH_OK;
106	0	}
107
108		#else
109		/* If set priv and pub should be initialized
110		* to NULL before calling this function*/
111		int ssh_dh_keypair_get_keys(struct dh_ctx *ctx, int peer,
112		bignum priv, bignum pub)
113		{
114		int rc;
115		if (((peer != DH_CLIENT_KEYPAIR) && (peer != DH_SERVER_KEYPAIR)) \|\|
116		((priv == NULL) && (pub == NULL)) \|\| (ctx == NULL) \|\|
117		(ctx->keypair[peer] == NULL)) {
118		return SSH_ERROR;
119		}
120
121		if (priv) {
122		rc = EVP_PKEY_get_bn_param(ctx->keypair[peer],
123		OSSL_PKEY_PARAM_PRIV_KEY,
124		priv);
125		if (rc != 1) {
126		return SSH_ERROR;
127		}
128		}
129		if (pub) {
130		rc = EVP_PKEY_get_bn_param(ctx->keypair[peer],
131		OSSL_PKEY_PARAM_PUB_KEY,
132		pub);
133		if (rc != 1) {
134		return SSH_ERROR;
135		}
136		}
137		if (priv && (priv == NULL \|\| bignum_num_bits(priv) == 0)) {
138		if (pub && (pub != NULL && bignum_num_bits(pub) != 0)) {
139		bignum_safe_free(*pub);
140		*pub = NULL;
141		}
142		return SSH_ERROR;
143		}
144		if (pub && (pub == NULL \|\| bignum_num_bits(pub) == 0)) {
145		if (priv) {
146		bignum_safe_free(*priv);
147		*priv = NULL;
148		}
149		return SSH_ERROR;
150		}
151
152		return SSH_OK;
153		}
154		#endif /* OPENSSL_VERSION_NUMBER */
155
156		int ssh_dh_keypair_set_keys(struct dh_ctx *ctx, int peer,
157		bignum priv, bignum pub)
158	0	{
159		#if OPENSSL_VERSION_NUMBER >= 0x30000000L
160		int rc;
161		OSSL_PARAM params = NULL, out_params = NULL, *merged_params = NULL;
162		OSSL_PARAM_BLD *param_bld = NULL;
163		EVP_PKEY_CTX *evp_ctx = NULL;
164		#endif /* OPENSSL_VERSION_NUMBER */
165
166	0	if (((peer != DH_CLIENT_KEYPAIR) && (peer != DH_SERVER_KEYPAIR)) \|\|
167	0	((priv == NULL) && (pub == NULL)) \|\| (ctx == NULL) \|\|
168	0	(ctx->keypair[peer] == NULL)) {
169	0	return SSH_ERROR;
170	0	}
171
172	0	#if OPENSSL_VERSION_NUMBER < 0x30000000L
173	0	(void)DH_set0_key(ctx->keypair[peer], pub, priv);
174
175	0	return SSH_OK;
176		#else
177		rc = EVP_PKEY_todata(ctx->keypair[peer], EVP_PKEY_KEYPAIR, &out_params);
178		if (rc != 1) {
179		return SSH_ERROR;
180		}
181
182		param_bld = OSSL_PARAM_BLD_new();
183		if (param_bld == NULL) {
184		rc = SSH_ERROR;
185		goto out;
186		}
187
188		evp_ctx = EVP_PKEY_CTX_new_from_pkey(NULL, ctx->keypair[peer], NULL);
189		if (evp_ctx == NULL) {
190		rc = SSH_ERROR;
191		goto out;
192		}
193
194		rc = EVP_PKEY_fromdata_init(evp_ctx);
195		if (rc != 1) {
196		rc = SSH_ERROR;
197		goto out;
198		}
199
200		if (priv) {
201		rc = OSSL_PARAM_BLD_push_BN(param_bld, OSSL_PKEY_PARAM_PRIV_KEY, priv);
202		if (rc != 1) {
203		rc = SSH_ERROR;
204		goto out;
205		}
206		}
207		if (pub) {
208		rc = OSSL_PARAM_BLD_push_BN(param_bld, OSSL_PKEY_PARAM_PUB_KEY, pub);
209		if (rc != 1) {
210		rc = SSH_ERROR;
211		goto out;
212		}
213		}
214
215		params = OSSL_PARAM_BLD_to_param(param_bld);
216		if (params == NULL) {
217		rc = SSH_ERROR;
218		goto out;
219		}
220		OSSL_PARAM_BLD_free(param_bld);
221
222		merged_params = OSSL_PARAM_merge(out_params, params);
223		if (merged_params == NULL) {
224		rc = SSH_ERROR;
225		goto out;
226		}
227
228		rc = EVP_PKEY_fromdata(evp_ctx,
229		&(ctx->keypair[peer]),
230		EVP_PKEY_PUBLIC_KEY,
231		merged_params);
232		if (rc != 1) {
233		rc = SSH_ERROR;
234		goto out;
235		}
236
237		rc = SSH_OK;
238		out:
239		bignum_safe_free(priv);
240		bignum_safe_free(pub);
241		EVP_PKEY_CTX_free(evp_ctx);
242		OSSL_PARAM_free(out_params);
243		OSSL_PARAM_free(params);
244		OSSL_PARAM_free(merged_params);
245
246		return rc;
247		#endif /* OPENSSL_VERSION_NUMBER */
248	0	}
249
250		#if OPENSSL_VERSION_NUMBER < 0x30000000L
251		int ssh_dh_get_parameters(struct dh_ctx *ctx,
252		const_bignum modulus, const_bignum generator)
253	0	{
254	0	if (ctx == NULL \|\| ctx->keypair[0] == NULL) {
255	0	return SSH_ERROR;
256	0	}
257	0	DH_get0_pqg(ctx->keypair[0], modulus, NULL, generator);
258	0	return SSH_OK;
259	0	}
260		#else
261		int ssh_dh_get_parameters(struct dh_ctx *ctx,
262		bignum modulus, bignum generator)
263		{
264		int rc;
265
266		if (ctx == NULL \|\| ctx->keypair[0] == NULL) {
267		return SSH_ERROR;
268		}
269
270		rc = EVP_PKEY_get_bn_param(ctx->keypair[0], OSSL_PKEY_PARAM_FFC_P, (BIGNUM**)modulus);
271		if (rc != 1) {
272		return SSH_ERROR;
273		}
274		rc = EVP_PKEY_get_bn_param(ctx->keypair[0], OSSL_PKEY_PARAM_FFC_G, (BIGNUM**)generator);
275		if (rc != 1) {
276		bignum_safe_free(*modulus);
277		return SSH_ERROR;
278		}
279
280		return SSH_OK;
281		}
282		#endif /* OPENSSL_VERSION_NUMBER */
283
284		int ssh_dh_set_parameters(struct dh_ctx *ctx,
285		const bignum modulus, const bignum generator)
286	0	{
287	0	size_t i;
288	0	int rc;
289		#if OPENSSL_VERSION_NUMBER >= 0x30000000L
290		OSSL_PARAM *params = NULL;
291		OSSL_PARAM_BLD *param_bld = NULL;
292		EVP_PKEY_CTX *evp_ctx = NULL;
293		#endif /* OPENSSL_VERSION_NUMBER */
294
295	0	if ((ctx == NULL) \|\| (modulus == NULL) \|\| (generator == NULL)) {
296	0	return SSH_ERROR;
297	0	}
298
299		#if OPENSSL_VERSION_NUMBER >= 0x30000000L
300		evp_ctx = EVP_PKEY_CTX_new_from_name(NULL, "DHX", NULL);
301		#endif
302
303	0	for (i = 0; i < 2; i++) {
304	0	#if OPENSSL_VERSION_NUMBER < 0x30000000L
305	0	bignum p = NULL;
306	0	bignum g = NULL;
307
308		/* when setting modulus or generator,
309		* make sure to invalidate existing keys */
310	0	DH_free(ctx->keypair[i]);
311	0	ctx->keypair[i] = DH_new();
312	0	if (ctx->keypair[i] == NULL) {
313	0	rc = SSH_ERROR;
314	0	goto done;
315	0	}
316
317	0	p = BN_dup(modulus);
318	0	g = BN_dup(generator);
319	0	rc = DH_set0_pqg(ctx->keypair[i], p, NULL, g);
320	0	if (rc != 1) {
321	0	BN_free(p);
322	0	BN_free(g);
323	0	rc = SSH_ERROR;
324	0	goto done;
325	0	}
326		#else
327		param_bld = OSSL_PARAM_BLD_new();
328
329		if (param_bld == NULL) {
330		rc = SSH_ERROR;
331		goto done;
332		}
333
334		rc = OSSL_PARAM_BLD_push_BN(param_bld, OSSL_PKEY_PARAM_FFC_P, modulus);
335		if (rc != 1) {
336		rc = SSH_ERROR;
337		goto done;
338		}
339		rc = OSSL_PARAM_BLD_push_BN(param_bld, OSSL_PKEY_PARAM_FFC_G, generator);
340		if (rc != 1) {
341		rc = SSH_ERROR;
342		goto done;
343		}
344		params = OSSL_PARAM_BLD_to_param(param_bld);
345		if (params == NULL) {
346		OSSL_PARAM_BLD_free(param_bld);
347		rc = SSH_ERROR;
348		goto done;
349		}
350		OSSL_PARAM_BLD_free(param_bld);
351
352		rc = EVP_PKEY_fromdata_init(evp_ctx);
353		if (rc != 1) {
354		OSSL_PARAM_free(params);
355		rc = SSH_ERROR;
356		goto done;
357		}
358
359		/* make sure to invalidate existing keys */
360		EVP_PKEY_free(ctx->keypair[i]);
361		ctx->keypair[i] = NULL;
362
363		rc = EVP_PKEY_fromdata(evp_ctx,
364		&(ctx->keypair[i]),
365		EVP_PKEY_KEY_PARAMETERS,
366		params);
367		if (rc != 1) {
368		OSSL_PARAM_free(params);
369		rc = SSH_ERROR;
370		goto done;
371		}
372
373		OSSL_PARAM_free(params);
374		#endif /* OPENSSL_VERSION_NUMBER */
375	0	}
376
377	0	rc = SSH_OK;
378	0	#if OPENSSL_VERSION_NUMBER < 0x30000000L
379	0	done:
380	0	if (rc != SSH_OK) {
381	0	DH_free(ctx->keypair[0]);
382	0	DH_free(ctx->keypair[1]);
383	0	}
384		#else
385		done:
386		EVP_PKEY_CTX_free(evp_ctx);
387
388		if (rc != SSH_OK) {
389		EVP_PKEY_free(ctx->keypair[0]);
390		EVP_PKEY_free(ctx->keypair[1]);
391		}
392		#endif /* OPENSSL_VERSION_NUMBER */
393	0	if (rc != SSH_OK) {
394	0	ctx->keypair[0] = NULL;
395	0	ctx->keypair[1] = NULL;
396	0	}
397
398	0	return rc;
399	0	}
400
401		/**
402		* @internal
403		* @brief allocate and initialize ephemeral values used in dh kex
404		*/
405		int ssh_dh_init_common(struct ssh_crypto_struct *crypto)
406	0	{
407	0	struct dh_ctx *ctx = NULL;
408	0	int rc;
409
410	0	ctx = calloc(1, sizeof(*ctx));
411	0	if (ctx == NULL) {
412	0	return SSH_ERROR;
413	0	}
414	0	crypto->dh_ctx = ctx;
415
416	0	switch (crypto->kex_type) {
417	0	case SSH_KEX_DH_GROUP1_SHA1:
418	0	rc = ssh_dh_set_parameters(ctx, ssh_dh_group1, ssh_dh_generator);
419	0	break;
420	0	case SSH_KEX_DH_GROUP14_SHA1:
421	0	case SSH_KEX_DH_GROUP14_SHA256:
422	0	rc = ssh_dh_set_parameters(ctx, ssh_dh_group14, ssh_dh_generator);
423	0	break;
424	0	case SSH_KEX_DH_GROUP16_SHA512:
425	0	rc = ssh_dh_set_parameters(ctx, ssh_dh_group16, ssh_dh_generator);
426	0	break;
427	0	case SSH_KEX_DH_GROUP18_SHA512:
428	0	rc = ssh_dh_set_parameters(ctx, ssh_dh_group18, ssh_dh_generator);
429	0	break;
430	0	default:
431	0	rc = SSH_OK;
432	0	break;
433	0	}
434
435	0	if (rc != SSH_OK) {
436	0	ssh_dh_cleanup(crypto);
437	0	}
438	0	return rc;
439	0	}
440
441		void ssh_dh_cleanup(struct ssh_crypto_struct *crypto)
442	0	{
443	0	if (crypto->dh_ctx != NULL) {
444	0	#if OPENSSL_VERSION_NUMBER < 0x30000000L
445	0	DH_free(crypto->dh_ctx->keypair[0]);
446	0	DH_free(crypto->dh_ctx->keypair[1]);
447		#else
448		EVP_PKEY_free(crypto->dh_ctx->keypair[0]);
449		EVP_PKEY_free(crypto->dh_ctx->keypair[1]);
450		#endif /* OPENSSL_VERSION_NUMBER */
451	0	free(crypto->dh_ctx);
452	0	crypto->dh_ctx = NULL;
453	0	}
454	0	}
455
456		/** @internal
457		* @brief generates a secret DH parameter of at least DH_SECURITY_BITS
458		* security as well as the corresponding public key.
459		*
460		* @param[out] params a dh_ctx that will hold the new keys.
461		* @param peer Select either client or server key storage. Valid values are:
462		* DH_CLIENT_KEYPAIR or DH_SERVER_KEYPAIR
463		*
464		* @return SSH_OK on success, SSH_ERROR on error
465		*/
466		int ssh_dh_keypair_gen_keys(struct dh_ctx *dh_ctx, int peer)
467	0	{
468	0	int rc;
469		#if OPENSSL_VERSION_NUMBER >= 0x30000000L
470		EVP_PKEY_CTX *evp_ctx = NULL;
471		#endif
472
473	0	if ((dh_ctx == NULL) \|\| (dh_ctx->keypair[peer] == NULL)) {
474	0	return SSH_ERROR;
475	0	}
476
477	0	#if OPENSSL_VERSION_NUMBER < 0x30000000L
478	0	rc = DH_generate_key(dh_ctx->keypair[peer]);
479	0	if (rc != 1) {
480	0	return SSH_ERROR;
481	0	}
482		#else
483		evp_ctx = EVP_PKEY_CTX_new_from_pkey(NULL, dh_ctx->keypair[peer], NULL);
484		if (evp_ctx == NULL) {
485		return SSH_ERROR;
486		}
487
488		rc = EVP_PKEY_keygen_init(evp_ctx);
489		if (rc != 1) {
490		EVP_PKEY_CTX_free(evp_ctx);
491		return SSH_ERROR;
492		}
493
494		rc = EVP_PKEY_generate(evp_ctx, &(dh_ctx->keypair[peer]));
495		if (rc != 1) {
496		EVP_PKEY_CTX_free(evp_ctx);
497		SSH_LOG(SSH_LOG_TRACE,
498		"Failed to generate DH: %s",
499		ERR_error_string(ERR_get_error(), NULL));
500		return SSH_ERROR;
501		}
502
503		EVP_PKEY_CTX_free(evp_ctx);
504		#endif /* OPENSSL_VERSION_NUMBER */
505
506	0	return SSH_OK;
507	0	}
508
509		/** @internal
510		* @brief generates a shared secret between the local peer and the remote
511		* peer. The local peer must have been initialized using either the
512		* ssh_dh_keypair_gen_keys() function or by seetting manually both
513		* the private and public keys. The remote peer only needs to have
514		* the remote's peer public key set.
515		* @param[in] local peer identifier (DH_CLIENT_KEYPAIR or DH_SERVER_KEYPAIR)
516		* @param[in] remote peer identifier (DH_CLIENT_KEYPAIR or DH_SERVER_KEYPAIR)
517		* @param[out] dest a new bignum with the shared secret value is returned.
518		* @return SSH_OK on success, SSH_ERROR on error
519		*/
520		int ssh_dh_compute_shared_secret(struct dh_ctx *dh_ctx, int local, int remote,
521		bignum *dest)
522	0	{
523	0	unsigned char *kstring = NULL;
524	0	int rc;
525	0	#if OPENSSL_VERSION_NUMBER < 0x30000000L
526	0	const_bignum pub_key = NULL;
527	0	int klen;
528		#else
529		size_t klen;
530		EVP_PKEY_CTX *evp_ctx = NULL;
531		#endif /* OPENSSL_VERSION_NUMBER */
532
533	0	if ((dh_ctx == NULL) \|\|
534	0	(dh_ctx->keypair[local] == NULL) \|\|
535	0	(dh_ctx->keypair[remote] == NULL)) {
536	0	return SSH_ERROR;
537	0	}
538
539	0	#if OPENSSL_VERSION_NUMBER < 0x30000000L
540	0	kstring = malloc(DH_size(dh_ctx->keypair[local]));
541	0	if (kstring == NULL) {
542	0	rc = SSH_ERROR;
543	0	goto done;
544	0	}
545
546	0	rc = ssh_dh_keypair_get_keys(dh_ctx, remote, NULL, &pub_key);
547	0	if (rc != SSH_OK) {
548	0	rc = SSH_ERROR;
549	0	goto done;
550	0	}
551
552	0	klen = DH_compute_key(kstring, pub_key, dh_ctx->keypair[local]);
553	0	if (klen == -1) {
554	0	rc = SSH_ERROR;
555	0	goto done;
556	0	}
557		#else
558		evp_ctx = EVP_PKEY_CTX_new_from_pkey(NULL, dh_ctx->keypair[local], NULL);
559
560		rc = EVP_PKEY_derive_init(evp_ctx);
561		if (rc != 1) {
562		rc = SSH_ERROR;
563		goto done;
564		}
565
566		rc = EVP_PKEY_derive_set_peer(evp_ctx, dh_ctx->keypair[remote]);
567		if (rc != 1) {
568		SSH_LOG(SSH_LOG_TRACE,
569		"Failed to set peer key: %s",
570		ERR_error_string(ERR_get_error(), NULL));
571		rc = SSH_ERROR;
572		goto done;
573		}
574
575		/* getting the size of the secret */
576		rc = EVP_PKEY_derive(evp_ctx, kstring, &klen);
577		if (rc != 1) {
578		rc = SSH_ERROR;
579		goto done;
580		}
581
582		kstring = malloc(klen);
583		if (kstring == NULL) {
584		rc = SSH_ERROR;
585		goto done;
586		}
587
588		rc = EVP_PKEY_derive(evp_ctx, kstring, &klen);
589		if (rc != 1) {
590		rc = SSH_ERROR;
591		goto done;
592		}
593		#endif /* OPENSSL_VERSION_NUMBER */
594
595	0	*dest = BN_bin2bn(kstring, (int)klen, NULL);
596	0	if (*dest == NULL) {
597	0	rc = SSH_ERROR;
598	0	goto done;
599	0	}
600
601	0	rc = SSH_OK;
602	0	done:
603		#if OPENSSL_VERSION_NUMBER >= 0x30000000L
604		EVP_PKEY_CTX_free(evp_ctx);
605		#endif
606	0	free(kstring);
607	0	return rc;
608	0	}