127 lines
3.9 KiB
C
127 lines
3.9 KiB
C
/*
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* chap-md5.c - New CHAP/MD5 implementation.
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*
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* Copyright (c) 2003 Paul Mackerras. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. The name(s) of the authors of this software must not be used to
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* endorse or promote products derived from this software without
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* prior written permission.
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*
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* 3. Redistributions of any form whatsoever must retain the following
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* acknowledgment:
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* "This product includes software developed by Paul Mackerras
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* <paulus@samba.org>".
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*
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* THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
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* THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
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* SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
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* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
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* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "lwip/opt.h"
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#if PPP_SUPPORT && CHAP_SUPPORT /* don't build if not configured for use in lwipopts.h */
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#if 0 /* UNUSED */
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#include <stdlib.h>
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#include <string.h>
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#endif /* UNUSED */
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#include "netif/ppp/ppp_impl.h"
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#include "netif/ppp/chap-new.h"
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#include "netif/ppp/chap-md5.h"
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#include "netif/ppp/magic.h"
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#if LWIP_INCLUDED_POLARSSL_MD5
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#include "netif/ppp/polarssl/md5.h"
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#else
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#include "polarssl/md5.h"
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#endif
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#define MD5_HASH_SIZE 16
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#define MD5_MIN_CHALLENGE 17
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#define MD5_MAX_CHALLENGE 24
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#define MD5_MIN_MAX_POWER_OF_TWO_CHALLENGE 3 /* 2^3-1 = 7, 17+7 = 24 */
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#if PPP_SERVER
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static void chap_md5_generate_challenge(ppp_pcb *pcb, unsigned char *cp) {
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int clen;
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LWIP_UNUSED_ARG(pcb);
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clen = MD5_MIN_CHALLENGE + magic_pow(MD5_MIN_MAX_POWER_OF_TWO_CHALLENGE);
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*cp++ = clen;
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magic_random_bytes(cp, clen);
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}
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static int chap_md5_verify_response(ppp_pcb *pcb, int id, const char *name,
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const unsigned char *secret, int secret_len,
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const unsigned char *challenge, const unsigned char *response,
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char *message, int message_space) {
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md5_context ctx;
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unsigned char idbyte = id;
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unsigned char hash[MD5_HASH_SIZE];
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int challenge_len, response_len;
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LWIP_UNUSED_ARG(name);
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LWIP_UNUSED_ARG(pcb);
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challenge_len = *challenge++;
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response_len = *response++;
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if (response_len == MD5_HASH_SIZE) {
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/* Generate hash of ID, secret, challenge */
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md5_starts(&ctx);
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md5_update(&ctx, &idbyte, 1);
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md5_update(&ctx, secret, secret_len);
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md5_update(&ctx, challenge, challenge_len);
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md5_finish(&ctx, hash);
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/* Test if our hash matches the peer's response */
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if (memcmp(hash, response, MD5_HASH_SIZE) == 0) {
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ppp_slprintf(message, message_space, "Access granted");
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return 1;
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}
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}
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ppp_slprintf(message, message_space, "Access denied");
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return 0;
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}
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#endif /* PPP_SERVER */
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static void chap_md5_make_response(ppp_pcb *pcb, unsigned char *response, int id, const char *our_name,
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const unsigned char *challenge, const char *secret, int secret_len,
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unsigned char *private_) {
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md5_context ctx;
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unsigned char idbyte = id;
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int challenge_len = *challenge++;
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LWIP_UNUSED_ARG(our_name);
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LWIP_UNUSED_ARG(private_);
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LWIP_UNUSED_ARG(pcb);
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md5_starts(&ctx);
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md5_update(&ctx, &idbyte, 1);
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md5_update(&ctx, (const u_char *)secret, secret_len);
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md5_update(&ctx, challenge, challenge_len);
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md5_finish(&ctx, &response[1]);
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response[0] = MD5_HASH_SIZE;
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}
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const struct chap_digest_type md5_digest = {
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CHAP_MD5, /* code */
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#if PPP_SERVER
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chap_md5_generate_challenge,
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chap_md5_verify_response,
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#endif /* PPP_SERVER */
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chap_md5_make_response,
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NULL, /* check_success */
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NULL, /* handle_failure */
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};
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#endif /* PPP_SUPPORT && CHAP_SUPPORT */
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