Exemplo n.º 1
0
Arquivo: kex.c Projeto: simonsj/libssh
/**
 * @brief sets the key exchange parameters to be sent to the server,
 *        in function of the options and available methods.
 */
int ssh_set_client_kex(ssh_session session)
{
    struct ssh_kex_struct *client= &session->next_crypto->client_kex;
    const char *wanted;
    char *kex = NULL;
    char *kex_tmp = NULL;
    int ok;
    int i;
    size_t kex_len, len;

    ok = ssh_get_random(client->cookie, 16, 0);
    if (!ok) {
        ssh_set_error(session, SSH_FATAL, "PRNG error");
        return SSH_ERROR;
    }

    memset(client->methods, 0, KEX_METHODS_SIZE * sizeof(char **));
    /* first check if we have specific host key methods */
    if (session->opts.wanted_methods[SSH_HOSTKEYS] == NULL) {
    	/* Only if no override */
    	session->opts.wanted_methods[SSH_HOSTKEYS] =
            ssh_client_select_hostkeys(session);
    }

    for (i = 0; i < KEX_METHODS_SIZE; i++) {
        wanted = session->opts.wanted_methods[i];
        if (wanted == NULL)
            wanted = default_methods[i];
        client->methods[i] = strdup(wanted);
        if (client->methods[i] == NULL) {
            ssh_set_error_oom(session);
            return SSH_ERROR;
        }
    }

    /* For rekeying, skip the extension negotiation */
    if (session->flags & SSH_SESSION_FLAG_AUTHENTICATED) {
        return SSH_OK;
    }

    /* Here we append  ext-info-c  to the list of kex algorithms */
    kex = client->methods[SSH_KEX];
    len = strlen(kex);
    if (len + strlen(KEX_EXTENSION_CLIENT) + 2 < len) {
        /* Overflow */
        return SSH_ERROR;
    }
    kex_len = len + strlen(KEX_EXTENSION_CLIENT) + 2; /* comma, NULL */
    kex_tmp = realloc(kex, kex_len);
    if (kex_tmp == NULL) {
        free(kex);
        ssh_set_error_oom(session);
        return SSH_ERROR;
    }
    snprintf(kex_tmp + len, kex_len - len, ",%s", KEX_EXTENSION_CLIENT);
    client->methods[SSH_KEX] = kex_tmp;

    return SSH_OK;
}
Exemplo n.º 2
0
/**
 * @brief sets the key exchange parameters to be sent to the server,
 *        in function of the options and available methods.
 */
int ssh_set_client_kex(ssh_session session){
    struct ssh_kex_struct *client= &session->next_crypto->client_kex;
    const char *wanted;
    int i;

    ssh_get_random(client->cookie, 16, 0);

    memset(client->methods, 0, KEX_METHODS_SIZE * sizeof(char **));
    /* first check if we have specific host key methods */
    if(session->opts.wanted_methods[SSH_HOSTKEYS] == NULL){
    	/* Only if no override */
    	session->opts.wanted_methods[SSH_HOSTKEYS] =
    			ssh_client_select_hostkeys(session);
    }

    for (i = 0; i < KEX_METHODS_SIZE; i++) {
        wanted = session->opts.wanted_methods[i];
        if (wanted == NULL)
            wanted = default_methods[i];
        client->methods[i] = strdup(wanted);
    }

    return SSH_OK;
}