src/userauth_kbd_packet.c - master - niceSOFT/libssh2

src/userauth_kbd_packet.c
153 строки6 KB
Viktor Szakats
tidy-up: C nits
28 июл 2026, 04:20
28 июл 2026, 04:209921aef
/* Copyright (C) Xaver Loppenstedt <xaver@loppenstedt.de>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. Neither the name of the copyright holder nor the names of its
 *    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 HOLDER 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.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include "libssh2_priv.h"
#include "userauth_kbd_packet.h"

int userauth_keyboard_interactive_decode_info_request(LIBSSH2_SESSION *session)
{
    unsigned char *language_tag;
    size_t language_tag_len;
    unsigned int i;
    unsigned char packet_type;
    uint32_t tmp_u32;

    struct string_buf decoded;

    decoded.data = session->userauth_kybd_data;
    decoded.dataptr = decoded.data;
    decoded.len = session->userauth_kybd_data_len;

    if(session->userauth_kybd_data_len < 17) {
        ssh2_err(session, LIBSSH2_ERROR_BUFFER_TOO_SMALL,
                 "userauth keyboard data buffer too small to get length");
        return -1;
    }

    /* byte      SSH_MSG_USERAUTH_INFO_REQUEST */
    ssh2_get_byte(&decoded, &packet_type);

    /* string    name (ISO-10646 UTF-8) */
    if(ssh2_copy_string(session, &decoded,
                        &session->userauth_kybd_auth_name,
                        &session->userauth_kybd_auth_name_len)) {
        ssh2_err(session, LIBSSH2_ERROR_ALLOC,
                 "Unable to decode keyboard-interactive 'name' "
                 "request field");
        return -1;
    }

    /* string    instruction (ISO-10646 UTF-8) */
    if(ssh2_copy_string(session, &decoded,
                        &session->userauth_kybd_auth_instruction,
                        &session->userauth_kybd_auth_instruction_len)) {
        ssh2_err(session, LIBSSH2_ERROR_ALLOC,
                 "Unable to decode keyboard-interactive 'instruction' "
                 "request field");
        return -1;
    }

    /* string    language tag (as defined in [RFC-3066]) */
    if(ssh2_get_string(&decoded, &language_tag, &language_tag_len)) {
        ssh2_err(session, LIBSSH2_ERROR_ALLOC,
                 "Unable to decode keyboard-interactive 'language tag' "
                 "request field");
        return -1;
    }

    /* int       num-prompts */
    if(ssh2_get_u32(&decoded, &tmp_u32)) {
        ssh2_err(session, LIBSSH2_ERROR_BUFFER_TOO_SMALL,
                 "Unable to decode "
                 "keyboard-interactive number of keyboard prompts");
        return -1;
    }

    session->userauth_kybd_num_prompts = tmp_u32;
    if(session->userauth_kybd_num_prompts != tmp_u32) {
        ssh2_err(session, LIBSSH2_ERROR_OUT_OF_BOUNDARY,
                 "Unable to decode "
                 "keyboard-interactive number of keyboard prompts");
        return -1;
    }

    if(session->userauth_kybd_num_prompts > 100) {
        ssh2_err(session, LIBSSH2_ERROR_OUT_OF_BOUNDARY,
                 "Too many replies for keyboard-interactive prompts");
        return -1;
    }

    if(session->userauth_kybd_num_prompts == 0) {
        return 0;
    }

    session->userauth_kybd_prompts =
        SSH2_CALLOC(session, sizeof(LIBSSH2_USERAUTH_KBDINT_PROMPT) *
                                 session->userauth_kybd_num_prompts);
    if(!session->userauth_kybd_prompts) {
        ssh2_err(session, LIBSSH2_ERROR_ALLOC,
                 "Unable to allocate memory for "
                 "keyboard-interactive prompts array");
        return -1;
    }

    session->userauth_kybd_responses =
        SSH2_CALLOC(session, sizeof(LIBSSH2_USERAUTH_KBDINT_RESPONSE) *
                                 session->userauth_kybd_num_prompts);
    if(!session->userauth_kybd_responses) {
        ssh2_err(session, LIBSSH2_ERROR_ALLOC,
                 "Unable to allocate memory for "
                 "keyboard-interactive responses array");
        return -1;
    }

    for(i = 0; i < session->userauth_kybd_num_prompts; i++) {
        /* string    prompt[1] (ISO-10646 UTF-8) */
        if(ssh2_copy_string(session, &decoded,
                            &session->userauth_kybd_prompts[i].text,
                            &session->userauth_kybd_prompts[i].length)) {
            ssh2_err(session, LIBSSH2_ERROR_ALLOC,
                     "Unable to decode keyboard-interactive prompt message");
            return -1;
        }

        /* boolean   echo[1] */
        if(ssh2_get_boolean(&decoded,
                            &session->userauth_kybd_prompts[i].echo)) {
            ssh2_err(session, LIBSSH2_ERROR_BUFFER_TOO_SMALL,
                     "Unable to decode user auth keyboard prompt echo");
            return -1;
        }
    }

    return 0;
}