/*

 * Copyright 2004-2018 The OpenSSL Project Authors. All Rights Reserved.

 * Copyright (c) 2004, EdelKey Project. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 *

 * Originally written by Christophe Renou and Peter Sylvester,

 * for the EdelKey project.

 */

#include <openssl/crypto.h>

#include <openssl/rand.h>

#include <openssl/err.h>

#include "ssl_local.h"

#ifndef OPENSSL_NO_SRP

# include <openssl/srp.h>

int SSL_CTX_SRP_CTX_free(struct ssl_ctx_st *ctx)

{

    if (ctx == NULL)

        return 0;

    OPENSSL_free(ctx->srp_ctx.login);

    OPENSSL_free(ctx->srp_ctx.info);

    BN_free(ctx->srp_ctx.N);

    BN_free(ctx->srp_ctx.g);

    BN_free(ctx->srp_ctx.s);

    BN_free(ctx->srp_ctx.B);

    BN_free(ctx->srp_ctx.A);

    BN_free(ctx->srp_ctx.a);

    BN_free(ctx->srp_ctx.b);

    BN_free(ctx->srp_ctx.v);

    memset(&ctx->srp_ctx, 0, sizeof(ctx->srp_ctx));

    ctx->srp_ctx.strength = SRP_MINIMAL_N;

    return 1;

}

int SSL_SRP_CTX_free(struct ssl_st *s)

{

    if (s == NULL)

        return 0;

    OPENSSL_free(s->srp_ctx.login);

    OPENSSL_free(s->srp_ctx.info);

    BN_free(s->srp_ctx.N);

    BN_free(s->srp_ctx.g);

    BN_free(s->srp_ctx.s);

    BN_free(s->srp_ctx.B);

    BN_free(s->srp_ctx.A);

    BN_free(s->srp_ctx.a);

    BN_free(s->srp_ctx.b);

    BN_free(s->srp_ctx.v);

    memset(&s->srp_ctx, 0, sizeof(s->srp_ctx));

    s->srp_ctx.strength = SRP_MINIMAL_N;

    return 1;

}

int SSL_SRP_CTX_init(struct ssl_st *s)

{

    SSL_CTX *ctx;

    if ((s == NULL) || ((ctx = s->ctx) == NULL))

        return 0;

    memset(&s->srp_ctx, 0, sizeof(s->srp_ctx));

    s->srp_ctx.SRP_cb_arg = ctx->srp_ctx.SRP_cb_arg;

    /* set client Hello login callback */

    s->srp_ctx.TLS_ext_srp_username_callback =

        ctx->srp_ctx.TLS_ext_srp_username_callback;

    /* set SRP N/g param callback for verification */

    s->srp_ctx.SRP_verify_param_callback =

        ctx->srp_ctx.SRP_verify_param_callback;

    /* set SRP client passwd callback */

    s->srp_ctx.SRP_give_srp_client_pwd_callback =

        ctx->srp_ctx.SRP_give_srp_client_pwd_callback;

    s->srp_ctx.strength = ctx->srp_ctx.strength;

    if (((ctx->srp_ctx.N != NULL) &&

         ((s->srp_ctx.N = BN_dup(ctx->srp_ctx.N)) == NULL)) ||

        ((ctx->srp_ctx.g != NULL) &&

         ((s->srp_ctx.g = BN_dup(ctx->srp_ctx.g)) == NULL)) ||

        ((ctx->srp_ctx.s != NULL) &&

         ((s->srp_ctx.s = BN_dup(ctx->srp_ctx.s)) == NULL)) ||

        ((ctx->srp_ctx.B != NULL) &&

         ((s->srp_ctx.B = BN_dup(ctx->srp_ctx.B)) == NULL)) ||

        ((ctx->srp_ctx.A != NULL) &&

         ((s->srp_ctx.A = BN_dup(ctx->srp_ctx.A)) == NULL)) ||

        ((ctx->srp_ctx.a != NULL) &&

         ((s->srp_ctx.a = BN_dup(ctx->srp_ctx.a)) == NULL)) ||

        ((ctx->srp_ctx.v != NULL) &&

         ((s->srp_ctx.v = BN_dup(ctx->srp_ctx.v)) == NULL)) ||

        ((ctx->srp_ctx.b != NULL) &&

         ((s->srp_ctx.b = BN_dup(ctx->srp_ctx.b)) == NULL))) {

        SSLerr(SSL_F_SSL_SRP_CTX_INIT, ERR_R_BN_LIB);

        goto err;

    }

    if ((ctx->srp_ctx.login != NULL) &&

        ((s->srp_ctx.login = OPENSSL_strdup(ctx->srp_ctx.login)) == NULL)) {

        SSLerr(SSL_F_SSL_SRP_CTX_INIT, ERR_R_INTERNAL_ERROR);

        goto err;

    }

    if ((ctx->srp_ctx.info != NULL) &&

        ((s->srp_ctx.info = BUF_strdup(ctx->srp_ctx.info)) == NULL)) {

        SSLerr(SSL_F_SSL_SRP_CTX_INIT, ERR_R_INTERNAL_ERROR);

        goto err;

    }

    s->srp_ctx.srp_Mask = ctx->srp_ctx.srp_Mask;

    return 1;

 err:

    OPENSSL_free(s->srp_ctx.login);

    OPENSSL_free(s->srp_ctx.info);

    BN_free(s->srp_ctx.N);

    BN_free(s->srp_ctx.g);

    BN_free(s->srp_ctx.s);

    BN_free(s->srp_ctx.B);

    BN_free(s->srp_ctx.A);

    BN_free(s->srp_ctx.a);

    BN_free(s->srp_ctx.b);

    BN_free(s->srp_ctx.v);

    memset(&s->srp_ctx, 0, sizeof(s->srp_ctx));

    return 0;

}

int SSL_CTX_SRP_CTX_init(struct ssl_ctx_st *ctx)

{

    if (ctx == NULL)

        return 0;

    memset(&ctx->srp_ctx, 0, sizeof(ctx->srp_ctx));

    ctx->srp_ctx.strength = SRP_MINIMAL_N;

    return 1;

}

/* server side */

int SSL_srp_server_param_with_username(SSL *s, int *ad)

{

    unsigned char b[SSL_MAX_MASTER_KEY_LENGTH];

    int al;

    *ad = SSL_AD_UNKNOWN_PSK_IDENTITY;

    if ((s->srp_ctx.TLS_ext_srp_username_callback != NULL) &&

        ((al =

          s->srp_ctx.TLS_ext_srp_username_callback(s, ad,

                                                   s->srp_ctx.SRP_cb_arg)) !=

         SSL_ERROR_NONE))

        return al;

    *ad = SSL_AD_INTERNAL_ERROR;

    if ((s->srp_ctx.N == NULL) ||

        (s->srp_ctx.g == NULL) ||

        (s->srp_ctx.s == NULL) || (s->srp_ctx.v == NULL))

        return SSL3_AL_FATAL;

    if (RAND_priv_bytes(b, sizeof(b)) <= 0)

        return SSL3_AL_FATAL;

    s->srp_ctx.b = BN_bin2bn(b, sizeof(b), NULL);

    OPENSSL_cleanse(b, sizeof(b));

    /* Calculate:  B = (kv + g^b) % N  */

    return ((s->srp_ctx.B =

             SRP_Calc_B(s->srp_ctx.b, s->srp_ctx.N, s->srp_ctx.g,

                        s->srp_ctx.v)) !=

            NULL) ? SSL_ERROR_NONE : SSL3_AL_FATAL;

}

/*

 * If the server just has the raw password, make up a verifier entry on the

 * fly

 */

int SSL_set_srp_server_param_pw(SSL *s, const char *user, const char *pass,

                                const char *grp)

{

    SRP_gN *GN = SRP_get_default_gN(grp);

    if (GN == NULL)

        return -1;

    s->srp_ctx.N = BN_dup(GN->N);

    s->srp_ctx.g = BN_dup(GN->g);

    BN_clear_free(s->srp_ctx.v);

    s->srp_ctx.v = NULL;

    BN_clear_free(s->srp_ctx.s);

    s->srp_ctx.s = NULL;

    if (!SRP_create_verifier_BN

        (user, pass, &s->srp_ctx.s, &s->srp_ctx.v, GN->N, GN->g))

        return -1;

    return 1;

}

int SSL_set_srp_server_param(SSL *s, const BIGNUM *N, const BIGNUM *g,

                             BIGNUM *sa, BIGNUM *v, char *info)

{

    if (N != NULL) {

        if (s->srp_ctx.N != NULL) {

            if (!BN_copy(s->srp_ctx.N, N)) {

                BN_free(s->srp_ctx.N);

                s->srp_ctx.N = NULL;

            }

        } else

            s->srp_ctx.N = BN_dup(N);

    }

    if (g != NULL) {

        if (s->srp_ctx.g != NULL) {

            if (!BN_copy(s->srp_ctx.g, g)) {

                BN_free(s->srp_ctx.g);

                s->srp_ctx.g = NULL;

            }

        } else

            s->srp_ctx.g = BN_dup(g);

    }

    if (sa != NULL) {

        if (s->srp_ctx.s != NULL) {

            if (!BN_copy(s->srp_ctx.s, sa)) {

                BN_free(s->srp_ctx.s);

                s->srp_ctx.s = NULL;

            }

        } else

            s->srp_ctx.s = BN_dup(sa);

    }

    if (v != NULL) {

        if (s->srp_ctx.v != NULL) {

            if (!BN_copy(s->srp_ctx.v, v)) {

                BN_free(s->srp_ctx.v);

                s->srp_ctx.v = NULL;

            }

        } else

            s->srp_ctx.v = BN_dup(v);

    }

    if (info != NULL) {

        if (s->srp_ctx.info)

            OPENSSL_free(s->srp_ctx.info);

        if ((s->srp_ctx.info = BUF_strdup(info)) == NULL)

            return -1;

    }

    if (!(s->srp_ctx.N) ||

        !(s->srp_ctx.g) || !(s->srp_ctx.s) || !(s->srp_ctx.v))

        return -1;

    return 1;

}

int srp_generate_server_master_secret(SSL *s)

{

    BIGNUM *K = NULL, *u = NULL;

    int ret = -1, tmp_len = 0;

    unsigned char *tmp = NULL;

    if (!SRP_Verify_A_mod_N(s->srp_ctx.A, s->srp_ctx.N))

        goto err;

    if ((u = SRP_Calc_u(s->srp_ctx.A, s->srp_ctx.B, s->srp_ctx.N)) == NULL)

        goto err;

    if ((K = SRP_Calc_server_key(s->srp_ctx.A, s->srp_ctx.v, u, s->srp_ctx.b,

                                 s->srp_ctx.N)) == NULL)

        goto err;

    tmp_len = BN_num_bytes(K);

    if ((tmp = OPENSSL_malloc(tmp_len)) == NULL) {

        SSLfatal(s, SSL_AD_INTERNAL_ERROR,

                 SSL_F_SRP_GENERATE_SERVER_MASTER_SECRET, ERR_R_MALLOC_FAILURE);

        goto err;

    }

    BN_bn2bin(K, tmp);

    /* Calls SSLfatal() as required */

    ret = ssl_generate_master_secret(s, tmp, tmp_len, 1);

 err:

    BN_clear_free(K);

    BN_clear_free(u);

    return ret;

}

/* client side */

int srp_generate_client_master_secret(SSL *s)

{

    BIGNUM *x = NULL, *u = NULL, *K = NULL;

    int ret = -1, tmp_len = 0;

    char *passwd = NULL;

    unsigned char *tmp = NULL;

    /*

     * Checks if b % n == 0

     */

    if (SRP_Verify_B_mod_N(s->srp_ctx.B, s->srp_ctx.N) == 0

            || (u = SRP_Calc_u(s->srp_ctx.A, s->srp_ctx.B, s->srp_ctx.N))

               == NULL

            || s->srp_ctx.SRP_give_srp_client_pwd_callback == NULL) {

        SSLfatal(s, SSL_AD_INTERNAL_ERROR,

                 SSL_F_SRP_GENERATE_CLIENT_MASTER_SECRET, ERR_R_INTERNAL_ERROR);

        goto err;

    }

    if ((passwd = s->srp_ctx.SRP_give_srp_client_pwd_callback(s,

                                                      s->srp_ctx.SRP_cb_arg))

            == NULL) {

        SSLfatal(s, SSL_AD_INTERNAL_ERROR,

                 SSL_F_SRP_GENERATE_CLIENT_MASTER_SECRET,

                 SSL_R_CALLBACK_FAILED);

        goto err;

    }

    if ((x = SRP_Calc_x(s->srp_ctx.s, s->srp_ctx.login, passwd)) == NULL

            || (K = SRP_Calc_client_key(s->srp_ctx.N, s->srp_ctx.B,

                                        s->srp_ctx.g, x,

                                        s->srp_ctx.a, u)) == NULL) {

        SSLfatal(s, SSL_AD_INTERNAL_ERROR,

                 SSL_F_SRP_GENERATE_CLIENT_MASTER_SECRET, ERR_R_INTERNAL_ERROR);

        goto err;

    }

    tmp_len = BN_num_bytes(K);

    if ((tmp = OPENSSL_malloc(tmp_len)) == NULL) {

        SSLfatal(s, SSL_AD_INTERNAL_ERROR,

                 SSL_F_SRP_GENERATE_CLIENT_MASTER_SECRET, ERR_R_MALLOC_FAILURE);

        goto err;

    }

    BN_bn2bin(K, tmp);

    /* Calls SSLfatal() as required */

    ret = ssl_generate_master_secret(s, tmp, tmp_len, 1);

 err:

    BN_clear_free(K);

    BN_clear_free(x);

    if (passwd != NULL)

        OPENSSL_clear_free(passwd, strlen(passwd));

    BN_clear_free(u);

    return ret;

}

int srp_verify_server_param(SSL *s)

{

    SRP_CTX *srp = &s->srp_ctx;

    /*

     * Sanity check parameters: we can quickly check B % N == 0 by checking B

     * != 0 since B < N

     */

    if (BN_ucmp(srp->g, srp->N) >= 0 || BN_ucmp(srp->B, srp->N) >= 0

        || BN_is_zero(srp->B)) {

        SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_SRP_VERIFY_SERVER_PARAM,

                 SSL_R_BAD_DATA);

        return 0;

    }

    if (BN_num_bits(srp->N) < srp->strength) {

        SSLfatal(s, SSL_AD_INSUFFICIENT_SECURITY, SSL_F_SRP_VERIFY_SERVER_PARAM,

                 SSL_R_INSUFFICIENT_SECURITY);

        return 0;

    }

    if (srp->SRP_verify_param_callback) {

        if (srp->SRP_verify_param_callback(s, srp->SRP_cb_arg) <= 0) {

            SSLfatal(s, SSL_AD_INSUFFICIENT_SECURITY,

                     SSL_F_SRP_VERIFY_SERVER_PARAM,

                     SSL_R_CALLBACK_FAILED);

            return 0;

        }

    } else if (!SRP_check_known_gN_param(srp->g, srp->N)) {

        SSLfatal(s, SSL_AD_INSUFFICIENT_SECURITY, SSL_F_SRP_VERIFY_SERVER_PARAM,

                 SSL_R_INSUFFICIENT_SECURITY);

        return 0;

    }

    return 1;

}

int SRP_Calc_A_param(SSL *s)

{

    unsigned char rnd[SSL_MAX_MASTER_KEY_LENGTH];

    if (RAND_priv_bytes(rnd, sizeof(rnd)) <= 0)

        return 0;

    s->srp_ctx.a = BN_bin2bn(rnd, sizeof(rnd), s->srp_ctx.a);

    OPENSSL_cleanse(rnd, sizeof(rnd));

    if (!(s->srp_ctx.A = SRP_Calc_A(s->srp_ctx.a, s->srp_ctx.N, s->srp_ctx.g)))

        return 0;

    return 1;

}

BIGNUM *SSL_get_srp_g(SSL *s)

{

    if (s->srp_ctx.g != NULL)

        return s->srp_ctx.g;

    return s->ctx->srp_ctx.g;

}

BIGNUM *SSL_get_srp_N(SSL *s)

{

    if (s->srp_ctx.N != NULL)

        return s->srp_ctx.N;

    return s->ctx->srp_ctx.N;

}

char *SSL_get_srp_username(SSL *s)

{

    if (s->srp_ctx.login != NULL)

        return s->srp_ctx.login;

    return s->ctx->srp_ctx.login;

}

char *SSL_get_srp_userinfo(SSL *s)

{

    if (s->srp_ctx.info != NULL)

        return s->srp_ctx.info;

    return s->ctx->srp_ctx.info;

}

# define tls1_ctx_ctrl ssl3_ctx_ctrl

# define tls1_ctx_callback_ctrl ssl3_ctx_callback_ctrl

int SSL_CTX_set_srp_username(SSL_CTX *ctx, char *name)

{

    return tls1_ctx_ctrl(ctx, SSL_CTRL_SET_TLS_EXT_SRP_USERNAME, 0, name);

}

int SSL_CTX_set_srp_password(SSL_CTX *ctx, char *password)

{

    return tls1_ctx_ctrl(ctx, SSL_CTRL_SET_TLS_EXT_SRP_PASSWORD, 0, password);

}

int SSL_CTX_set_srp_strength(SSL_CTX *ctx, int strength)

{

    return tls1_ctx_ctrl(ctx, SSL_CTRL_SET_TLS_EXT_SRP_STRENGTH, strength,

                         NULL);

}

int SSL_CTX_set_srp_verify_param_callback(SSL_CTX *ctx,

                                          int (*cb) (SSL *, void *))

{

    return tls1_ctx_callback_ctrl(ctx, SSL_CTRL_SET_SRP_VERIFY_PARAM_CB,

                                  (void (*)(void))cb);

}

int SSL_CTX_set_srp_cb_arg(SSL_CTX *ctx, void *arg)

{

    return tls1_ctx_ctrl(ctx, SSL_CTRL_SET_SRP_ARG, 0, arg);

}

int SSL_CTX_set_srp_username_callback(SSL_CTX *ctx,

                                      int (*cb) (SSL *, int *, void *))

{

    return tls1_ctx_callback_ctrl(ctx, SSL_CTRL_SET_TLS_EXT_SRP_USERNAME_CB,

                                  (void (*)(void))cb);

}

int SSL_CTX_set_srp_client_pwd_callback(SSL_CTX *ctx,

                                        char *(*cb) (SSL *, void *))

{

    return tls1_ctx_callback_ctrl(ctx, SSL_CTRL_SET_SRP_GIVE_CLIENT_PWD_CB,

                                  (void (*)(void))cb);

}

#endif