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Annotation of src/usr.bin/ssh/auth2-chall.c, Revision 1.1

1.1     ! markus      1: /*
        !             2:  * Copyright (c) 2001 Markus Friedl. All rights reserved.
        !             3:  *
        !             4:  * Redistribution and use in source and binary forms, with or without
        !             5:  * modification, are permitted provided that the following conditions
        !             6:  * are met:
        !             7:  * 1. Redistributions of source code must retain the above copyright
        !             8:  *    notice, this list of conditions and the following disclaimer.
        !             9:  * 2. Redistributions in binary form must reproduce the above copyright
        !            10:  *    notice, this list of conditions and the following disclaimer in the
        !            11:  *    documentation and/or other materials provided with the distribution.
        !            12:  *
        !            13:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
        !            14:  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
        !            15:  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
        !            16:  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
        !            17:  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
        !            18:  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
        !            19:  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
        !            20:  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
        !            21:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
        !            22:  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
        !            23:  */
        !            24: #include "includes.h"
        !            25: RCSID("$OpenBSD: auth2-skey.c,v 1.3 2001/01/18 16:59:59 markus Exp $");
        !            26:
        !            27: #include "ssh.h"
        !            28: #include "ssh2.h"
        !            29: #include "auth.h"
        !            30: #include "packet.h"
        !            31: #include "xmalloc.h"
        !            32: #include "dispatch.h"
        !            33:
        !            34: void send_userauth_into_request(Authctxt *authctxt, char *challenge, int echo);
        !            35: void input_userauth_info_response(int type, int plen, void *ctxt);
        !            36:
        !            37: /*
        !            38:  * try challenge-reponse, return -1 (= postponed) if we have to
        !            39:  * wait for the response.
        !            40:  */
        !            41: int
        !            42: auth2_challenge(Authctxt *authctxt, char *devs)
        !            43: {
        !            44:        char *challenge;
        !            45:
        !            46:        if (!authctxt->valid || authctxt->user == NULL)
        !            47:                return 0;
        !            48:        if ((challenge = get_challenge(authctxt, devs)) == NULL)
        !            49:                return 0;
        !            50:        send_userauth_into_request(authctxt, challenge, 0);
        !            51:        dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE,
        !            52:            &input_userauth_info_response);
        !            53:        authctxt->postponed = 1;
        !            54:        return 0;
        !            55: }
        !            56:
        !            57: void
        !            58: send_userauth_into_request(Authctxt *authctxt, char *challenge, int echo)
        !            59: {
        !            60:        int nprompts = 1;
        !            61:
        !            62:        packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
        !            63:        /* name, instruction and language are unused */
        !            64:        packet_put_cstring("");
        !            65:        packet_put_cstring("");
        !            66:        packet_put_cstring("");
        !            67:        packet_put_int(nprompts);
        !            68:        packet_put_cstring(challenge);
        !            69:        packet_put_char(echo);
        !            70:        packet_send();
        !            71:        packet_write_wait();
        !            72: }
        !            73:
        !            74: void
        !            75: input_userauth_info_response(int type, int plen, void *ctxt)
        !            76: {
        !            77:        Authctxt *authctxt = ctxt;
        !            78:        int authenticated = 0;
        !            79:        u_int nresp, rlen;
        !            80:        char *response, *method = "challenge-reponse";
        !            81:
        !            82:        if (authctxt == NULL)
        !            83:                fatal("input_userauth_info_response: no authctxt");
        !            84:
        !            85:        authctxt->postponed = 0;        /* reset */
        !            86:        nresp = packet_get_int();
        !            87:        if (nresp == 1) {
        !            88:                response = packet_get_string(&rlen);
        !            89:                packet_done();
        !            90:                if (strlen(response) == 0) {
        !            91:                        /*
        !            92:                         * if we received an empty response, resend challenge
        !            93:                         * with echo enabled
        !            94:                         */
        !            95:                        char *challenge = get_challenge(authctxt, NULL);
        !            96:                        if (challenge != NULL) {
        !            97:                                send_userauth_into_request(authctxt,
        !            98:                                    challenge, 1);
        !            99:                                authctxt->postponed = 1;
        !           100:                        }
        !           101:                } else if (authctxt->valid) {
        !           102:                        authenticated = verify_response(authctxt, response);
        !           103:                        memset(response, 'r', rlen);
        !           104:                }
        !           105:                xfree(response);
        !           106:        }
        !           107:        auth_log(authctxt, authenticated, method, " ssh2");
        !           108:        if (!authctxt->postponed) {
        !           109:                /* unregister callback and send reply */
        !           110:                dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);
        !           111:                userauth_reply(authctxt, authenticated);
        !           112:        }
        !           113: }