232 lines
7.2 KiB
C
232 lines
7.2 KiB
C
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/*
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* Copyright 1995-2023 The OpenSSL Project Authors. All Rights Reserved.
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* Copyright 2005 Nokia. All rights reserved.
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*
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* Licensed under the Apache License 2.0 (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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/*
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* This file is to enable backwards compatibility for the SRP features of
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* s_client, s_server and ciphers. All of those features are deprecated and will
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* eventually disappear. In the meantime, to continue to support them, we
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* need to access deprecated SRP APIs.
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*/
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#define OPENSSL_SUPPRESS_DEPRECATED
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#include <openssl/bn.h>
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#include <openssl/bio.h>
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#include <openssl/ssl.h>
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#include <openssl/srp.h>
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#include "apps_ui.h"
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#include "apps.h"
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#include "s_apps.h"
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static int srp_Verify_N_and_g(const BIGNUM *N, const BIGNUM *g)
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{
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BN_CTX *bn_ctx = BN_CTX_new();
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BIGNUM *p = BN_new();
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BIGNUM *r = BN_new();
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int ret =
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g != NULL && N != NULL && bn_ctx != NULL && BN_is_odd(N) &&
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BN_check_prime(N, bn_ctx, NULL) == 1 &&
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p != NULL && BN_rshift1(p, N) &&
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/* p = (N-1)/2 */
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BN_check_prime(p, bn_ctx, NULL) == 1 &&
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r != NULL &&
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/* verify g^((N-1)/2) == -1 (mod N) */
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BN_mod_exp(r, g, p, N, bn_ctx) &&
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BN_add_word(r, 1) && BN_cmp(r, N) == 0;
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BN_free(r);
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BN_free(p);
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BN_CTX_free(bn_ctx);
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return ret;
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}
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/*-
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* This callback is used here for two purposes:
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* - extended debugging
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* - making some primality tests for unknown groups
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* The callback is only called for a non default group.
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*
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* An application does not need the call back at all if
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* only the standard groups are used. In real life situations,
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* client and server already share well known groups,
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* thus there is no need to verify them.
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* Furthermore, in case that a server actually proposes a group that
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* is not one of those defined in RFC 5054, it is more appropriate
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* to add the group to a static list and then compare since
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* primality tests are rather cpu consuming.
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*/
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static int ssl_srp_verify_param_cb(SSL *s, void *arg)
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{
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SRP_ARG *srp_arg = (SRP_ARG *)arg;
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BIGNUM *N = NULL, *g = NULL;
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if (((N = SSL_get_srp_N(s)) == NULL) || ((g = SSL_get_srp_g(s)) == NULL))
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return 0;
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if (srp_arg->debug || srp_arg->msg || srp_arg->amp == 1) {
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BIO_printf(bio_err, "SRP parameters:\n");
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BIO_printf(bio_err, "\tN=");
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BN_print(bio_err, N);
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BIO_printf(bio_err, "\n\tg=");
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BN_print(bio_err, g);
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BIO_printf(bio_err, "\n");
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}
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if (SRP_check_known_gN_param(g, N))
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return 1;
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if (srp_arg->amp == 1) {
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if (srp_arg->debug)
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BIO_printf(bio_err,
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"SRP param N and g are not known params, going to check deeper.\n");
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/*
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* The srp_moregroups is a real debugging feature. Implementers
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* should rather add the value to the known ones. The minimal size
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* has already been tested.
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*/
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if (BN_num_bits(g) <= BN_BITS && srp_Verify_N_and_g(N, g))
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return 1;
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}
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BIO_printf(bio_err, "SRP param N and g rejected.\n");
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return 0;
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}
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#define PWD_STRLEN 1024
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static char *ssl_give_srp_client_pwd_cb(SSL *s, void *arg)
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{
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SRP_ARG *srp_arg = (SRP_ARG *)arg;
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char *pass = app_malloc(PWD_STRLEN + 1, "SRP password buffer");
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PW_CB_DATA cb_tmp;
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int l;
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cb_tmp.password = (char *)srp_arg->srppassin;
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cb_tmp.prompt_info = "SRP user";
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if ((l = password_callback(pass, PWD_STRLEN, 0, &cb_tmp)) < 0) {
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BIO_printf(bio_err, "Can't read Password\n");
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OPENSSL_free(pass);
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return NULL;
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}
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*(pass + l) = '\0';
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return pass;
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}
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int set_up_srp_arg(SSL_CTX *ctx, SRP_ARG *srp_arg, int srp_lateuser, int c_msg,
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int c_debug)
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{
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if (!srp_lateuser && !SSL_CTX_set_srp_username(ctx, srp_arg->srplogin)) {
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BIO_printf(bio_err, "Unable to set SRP username\n");
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return 0;
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}
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srp_arg->msg = c_msg;
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srp_arg->debug = c_debug;
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SSL_CTX_set_srp_cb_arg(ctx, &srp_arg);
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SSL_CTX_set_srp_client_pwd_callback(ctx, ssl_give_srp_client_pwd_cb);
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SSL_CTX_set_srp_strength(ctx, srp_arg->strength);
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if (c_msg || c_debug || srp_arg->amp == 0)
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SSL_CTX_set_srp_verify_param_callback(ctx, ssl_srp_verify_param_cb);
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return 1;
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}
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static char *dummy_srp(SSL *ssl, void *arg)
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{
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return "";
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}
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void set_up_dummy_srp(SSL_CTX *ctx)
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{
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SSL_CTX_set_srp_client_pwd_callback(ctx, dummy_srp);
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}
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/*
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* This callback pretends to require some asynchronous logic in order to
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* obtain a verifier. When the callback is called for a new connection we
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* return with a negative value. This will provoke the accept etc to return
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* with an LOOKUP_X509. The main logic of the reinvokes the suspended call
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* (which would normally occur after a worker has finished) and we set the
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* user parameters.
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*/
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static int ssl_srp_server_param_cb(SSL *s, int *ad, void *arg)
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{
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srpsrvparm *p = (srpsrvparm *) arg;
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int ret = SSL3_AL_FATAL;
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if (p->login == NULL && p->user == NULL) {
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p->login = SSL_get_srp_username(s);
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BIO_printf(bio_err, "SRP username = \"%s\"\n", p->login);
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return -1;
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}
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if (p->user == NULL) {
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BIO_printf(bio_err, "User %s doesn't exist\n", p->login);
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goto err;
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}
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if (SSL_set_srp_server_param
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(s, p->user->N, p->user->g, p->user->s, p->user->v,
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p->user->info) < 0) {
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*ad = SSL_AD_INTERNAL_ERROR;
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goto err;
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}
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BIO_printf(bio_err,
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"SRP parameters set: username = \"%s\" info=\"%s\" \n",
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p->login, p->user->info);
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ret = SSL_ERROR_NONE;
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err:
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SRP_user_pwd_free(p->user);
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p->user = NULL;
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p->login = NULL;
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return ret;
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}
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int set_up_srp_verifier_file(SSL_CTX *ctx, srpsrvparm *srp_callback_parm,
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char *srpuserseed, char *srp_verifier_file)
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{
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int ret;
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srp_callback_parm->vb = SRP_VBASE_new(srpuserseed);
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srp_callback_parm->user = NULL;
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srp_callback_parm->login = NULL;
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if (srp_callback_parm->vb == NULL) {
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BIO_printf(bio_err, "Failed to initialize SRP verifier file \n");
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return 0;
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}
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if ((ret =
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SRP_VBASE_init(srp_callback_parm->vb,
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srp_verifier_file)) != SRP_NO_ERROR) {
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BIO_printf(bio_err,
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"Cannot initialize SRP verifier file \"%s\":ret=%d\n",
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srp_verifier_file, ret);
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return 0;
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}
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SSL_CTX_set_verify(ctx, SSL_VERIFY_NONE, verify_callback);
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SSL_CTX_set_srp_cb_arg(ctx, &srp_callback_parm);
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SSL_CTX_set_srp_username_callback(ctx, ssl_srp_server_param_cb);
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return 1;
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}
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void lookup_srp_user(srpsrvparm *srp_callback_parm, BIO *bio_s_out)
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{
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SRP_user_pwd_free(srp_callback_parm->user);
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srp_callback_parm->user = SRP_VBASE_get1_by_user(srp_callback_parm->vb,
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srp_callback_parm->login);
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if (srp_callback_parm->user != NULL)
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BIO_printf(bio_s_out, "LOOKUP done %s\n",
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srp_callback_parm->user->info);
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else
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BIO_printf(bio_s_out, "LOOKUP not successful\n");
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}
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