mirror of
https://git.kernel.org/pub/scm/network/wireless/iwd.git
synced 2024-12-19 18:22:32 +01:00
eap-mschap: Add crypto functions for mschapv2
Add the key-derivation and hash functions required for mschapv2. The eap-mschapv2 protocol can be implemented on top of these functions.
This commit is contained in:
Markus Ongyerth
Denis Kenzior
parent
6e729f6175
commit
1baa6ec04c
@ -76,6 +76,7 @@ src_iwd_SOURCES = src/main.c linux/nl80211.h \
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src/eap-wsc.h src/eap-wsc.c \
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src/eap.h src/eap.c src/eap-md5.c \
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src/eap-tls.c src/eap-ttls.c \
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src/eap-mschapv2.c src/eap-mschapv2.h \
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src/backtrace.h src/backtrace.c \
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src/knownnetworks.h \
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src/knownnetworks.c \
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355
src/eap-mschapv2.c
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355
src/eap-mschapv2.c
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@ -0,0 +1,355 @@
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/*
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*
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* Wireless daemon for Linux
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*
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* Copyright (C) 2016 Markus Ongyerth. All rights reserved.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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#include <ell/ell.h>
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#include <ctype.h>
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#include "eap-mschapv2.h"
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/**
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* Generate the asymetric start keys from our mschapv2 master key for MPPE
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* This function is specified in:
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* https://tools.ietf.org/html/draft-ietf-pppext-mschapv2-keys-02
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*
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* @master_key: The master key
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* @session_key: the destination
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* @session_len: The length of the requested key in octets (<= 20)
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* @server: if the key should be generated for server side
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* @send: if the send or the receive key should be generated
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*
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* Returns: true on success, false if hash/encrypt couldn't be done
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**/
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bool mschapv2_get_asymmetric_start_key(const uint8_t master_key[static 16],
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uint8_t *session_key, size_t session_len,
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bool server, bool send)
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{
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static const uint8_t magic2[] = {
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0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
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0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
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0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
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0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20, 0x6b, 0x65, 0x79,
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0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x73,
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0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73, 0x69, 0x64, 0x65,
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0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
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0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
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0x6b, 0x65, 0x79, 0x2e
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};
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static const uint8_t magic3[] = {
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0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
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0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
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0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
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0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
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0x6b, 0x65, 0x79, 0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68,
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0x65, 0x20, 0x73, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73,
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0x69, 0x64, 0x65, 0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73,
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0x20, 0x74, 0x68, 0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20,
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0x6b, 0x65, 0x79, 0x2e
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};
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static const uint8_t shs_pad1[] = {
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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};
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static const uint8_t shs_pad2[] = {
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0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
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0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
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0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
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0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2
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};
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const uint8_t *magic;
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struct l_checksum *check;
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if (send == server)
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magic = magic3;
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else
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magic = magic2;
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check = l_checksum_new(L_CHECKSUM_SHA1);
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if (!check)
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return false;
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l_checksum_update(check, master_key, 16);
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l_checksum_update(check, shs_pad1, 40);
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l_checksum_update(check, magic, 84);
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l_checksum_update(check, shs_pad2, 40);
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l_checksum_get_digest(check, session_key, session_len);
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l_checksum_free(check);
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return true;
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}
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/**
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* Generate the master key for MPPE from mschapv2
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* This function is specified in:
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* https://tools.ietf.org/html/draft-ietf-pppext-mschapv2-keys-02
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*
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* @pw_hash_hash: The MD4 hash of the password hash
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* @nt_response: The nt_response generated for mschapv2
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* @master_key: The destination
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*
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* Returns: true on success, false if hash/encrypt couldn't be done
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**/
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bool mschapv2_get_master_key(const uint8_t pw_hash_hash[static 16],
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const uint8_t nt_response[static 24],
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uint8_t master_key[static 16])
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{
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static const uint8_t magic[] = {
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0x54, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74,
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0x68, 0x65, 0x20, 0x4d, 0x50, 0x50, 0x45, 0x20, 0x4d,
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0x61, 0x73, 0x74, 0x65, 0x72, 0x20, 0x4b, 0x65, 0x79
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};
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struct l_checksum *check;
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check = l_checksum_new(L_CHECKSUM_SHA1);
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if (!check)
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return false;
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l_checksum_update(check, pw_hash_hash, 16);
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l_checksum_update(check, nt_response, 24);
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l_checksum_update(check, magic, sizeof(magic));
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l_checksum_get_digest(check, master_key, 16);
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l_checksum_free(check);
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return true;
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}
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/**
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* Internal function to generate the challenge used in nt_response
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* https://tools.ietf.org/html/rfc2759
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*
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* @peer_challenge: The challenge generated by the peer (us)
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* @server_challenge: The challenge generated by the authenticator
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* @user: The username utf8 encoded
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* @challenge: The destination
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*
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* Returns: true on success, false if hash/encrypt couldn't be done
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**/
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static bool mschapv2_challenge_hash(const uint8_t *peer_challenge,
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const uint8_t *server_challenge,
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const char *user, uint8_t challenge[static 8])
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{
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struct l_checksum *check;
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check = l_checksum_new(L_CHECKSUM_SHA1);
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if (!check)
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return false;
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l_checksum_update(check, peer_challenge, 16);
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l_checksum_update(check, server_challenge, 16);
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l_checksum_update(check, user, strlen(user));
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l_checksum_get_digest(check, challenge, 8);
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l_checksum_free(check);
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return true;
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}
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/**
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* Hash the utf8 encoded nt password.
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* It is asumed, that the password is valid utf8!
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* The rfc says "unicode-char", but never specifies which encoding.
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* This function converts the password to ucs-2.
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* The example in the code uses LE for the unicode chars, so it is forced here.
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* https://tools.ietf.org/html/draft-ietf-pppext-mschap-00#ref-8
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*/
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bool mschapv2_nt_password_hash(const char *password, uint8_t hash[static 16])
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{
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size_t size = l_utf8_strlen(password);
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size_t bsize = strlen(password);
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uint16_t buffer[size];
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unsigned int i, pos;
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struct l_checksum *check;
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for (i = 0, pos = 0; i < size; ++i) {
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wchar_t val;
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pos += l_utf8_get_codepoint(password + pos, bsize - pos, &val);
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if (val > 0xFFFF) {
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l_error("Encountered password with value not valid in ucs-2");
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return false;
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}
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buffer[i] = L_CPU_TO_LE16(val);
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}
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check = l_checksum_new(L_CHECKSUM_MD4);
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if (!check)
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return false;
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l_checksum_update(check, (uint8_t *) buffer, size * 2);
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l_checksum_get_digest(check, hash, 16);
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l_checksum_free(check);
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return true;
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}
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/**
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* Internal function for generate_nt_response.
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* The DES keys specified for generate_nt_response are 56bit, while the api we
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* use takes 64bit keys, so we have to generate the parity bits.
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**/
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static bool mschapv2_des_encrypt(const uint8_t challenge[static 8],
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const uint8_t key[static 7],
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uint8_t cipher_text[static 8])
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{
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uint8_t pkey[8], tmp;
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int i;
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struct l_cipher *cipher;
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uint8_t next;
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for (i = 0, next = 0; i < 7; ++i) {
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tmp = key[i];
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pkey[i] = (tmp >> i) | next | 1;
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next = tmp << (7 - i);
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}
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pkey[i] = next | 1;
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cipher = l_cipher_new(L_CIPHER_DES, pkey, 8);
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if (!cipher)
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return false;
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l_cipher_encrypt(cipher, challenge, cipher_text, 8);
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l_cipher_free(cipher);
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return true;
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}
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/**
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* Generate the nt_response for mschapv2.
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* This function is specified in:
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* https://tools.ietf.org/html/rfc2759
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*
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* @password_hash: The MD4 hash of the ucs2 encoded user password
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* @peer_challenge: the challenge generated by the peer (us)
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* @server_challenge: the challenge generated by the authenticator
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* @user: The username, utf8 encoded
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* @nt_response: The destination
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*
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* Returns: true on success, false if hash/encrypt couldn't be done
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**/
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bool mschapv2_generate_nt_response(const uint8_t password_hash[static 16],
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const uint8_t peer_challenge[static 16],
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const uint8_t server_challenge[static 16],
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const char *user, uint8_t response[static 24])
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{
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uint8_t challenge[8];
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uint8_t buffer[21];
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memset(buffer, 0, sizeof(buffer));
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memcpy(buffer, password_hash, 16);
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if (!mschapv2_challenge_hash(peer_challenge, server_challenge, user,
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challenge))
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return false;
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if (!mschapv2_des_encrypt(challenge, buffer + 0, response + 0)
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|| !mschapv2_des_encrypt(challenge, buffer + 7, response + 8)
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|| !mschapv2_des_encrypt(challenge, buffer + 14, response + 16))
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return false;
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return true;
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}
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/**
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* Generate the mschapv2 authenticator response for verifying authenticator
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* This function is specified in:
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* https://tools.ietf.org/html/rfc2759
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*
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* @password_hash_hash: The MD4 hash of the password hash
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* @nt_response: The nt_response generated for this exchange
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* @peer_challenge: The challenge generated by the peer (us)
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* @server_challenge: The challenge generated by the authenticator
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* @user: The username utf8 encoded
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* @response: The destination
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*
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* Returns: true on success, false if hash/encrypt couldn't be done
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**/
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bool mschapv2_generate_authenticator_response(
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const uint8_t pw_hash_hash[static 16],
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const uint8_t nt_response[static 24],
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const uint8_t peer_challenge[static 16],
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const uint8_t server_challenge[static 16],
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const char *user, char response[static 42])
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{
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static const uint8_t magic1[] =
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{ 0x4D, 0x61, 0x67, 0x69, 0x63, 0x20, 0x73, 0x65, 0x72, 0x76,
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0x65, 0x72, 0x20, 0x74, 0x6F, 0x20, 0x63, 0x6C, 0x69, 0x65,
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0x6E, 0x74, 0x20, 0x73, 0x69, 0x67, 0x6E, 0x69, 0x6E, 0x67,
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0x20, 0x63, 0x6F, 0x6E, 0x73, 0x74, 0x61, 0x6E, 0x74};
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static const uint8_t magic2[] =
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{ 0x50, 0x61, 0x64, 0x20, 0x74, 0x6F, 0x20, 0x6D, 0x61, 0x6B,
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0x65, 0x20, 0x69, 0x74, 0x20, 0x64, 0x6F, 0x20, 0x6D, 0x6F,
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0x72, 0x65, 0x20, 0x74, 0x68, 0x61, 0x6E, 0x20, 0x6F, 0x6E,
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0x65, 0x20, 0x69, 0x74, 0x65, 0x72, 0x61, 0x74, 0x69, 0x6F,
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0x6E};
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uint8_t digest[20];
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uint8_t challenge[8];
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char *ascii;
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int i;
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struct l_checksum *check;
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check = l_checksum_new(L_CHECKSUM_SHA1);
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if (!check)
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return false;
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l_checksum_update(check, pw_hash_hash, 16);
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l_checksum_update(check, nt_response, 24);
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l_checksum_update(check, magic1, sizeof(magic1));
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l_checksum_get_digest(check, digest, sizeof(digest));
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l_checksum_free(check);
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if (!mschapv2_challenge_hash(peer_challenge, server_challenge, user,
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challenge))
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return false;
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check = l_checksum_new(L_CHECKSUM_SHA1);
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if (!check)
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return false;
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l_checksum_update(check, digest, sizeof(digest));
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l_checksum_update(check, challenge, sizeof(challenge));
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l_checksum_update(check, magic2, sizeof(magic2));
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l_checksum_get_digest(check, digest, sizeof(digest));
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l_checksum_free(check);
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response[0] = 'S';
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response[1] = '=';
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ascii = l_util_hexstring(digest, sizeof(digest));
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if (!ascii)
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return false;
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for (i = 0; i < 40; ++i) {
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response[i + 2] = toupper(ascii[i]);
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}
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l_free(ascii);
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return true;
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}
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53
src/eap-mschapv2.h
Normal file
53
src/eap-mschapv2.h
Normal file
@ -0,0 +1,53 @@
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/*
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*
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* Wireless daemon for Linux
|
||||
*
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* Copyright (C) 2016 Markus Ongyerth. All rights reserved.
|
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*
|
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* This library is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU Lesser General Public
|
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* License as published by the Free Software Foundation; either
|
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* version 2.1 of the License, or (at your option) any later version.
|
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*
|
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* This library is distributed in the hope that it will be useful,
|
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||||
* Lesser General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU Lesser General Public
|
||||
* License along with this library; if not, write to the Free Software
|
||||
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <stdio.h>
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#include <stdint.h>
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#include <stdbool.h>
|
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bool mschapv2_get_asymmetric_start_key(const uint8_t master_key[static 16],
|
||||
uint8_t *session_key, size_t session_len,
|
||||
bool server, bool send);
|
||||
|
||||
bool mschapv2_get_master_key(const uint8_t pw_hash_hash[static 16],
|
||||
const uint8_t nt_response[static 24],
|
||||
uint8_t master_key[static 16]);
|
||||
|
||||
bool mschapv2_nt_password_hash(const char *password, uint8_t hash[16]);
|
||||
|
||||
bool mschapv2_generate_nt_response(const uint8_t password_hash[static 16],
|
||||
const uint8_t peer_challenge[static 16],
|
||||
const uint8_t server_challenge[static 16],
|
||||
const char *user,
|
||||
uint8_t response[static 24]);
|
||||
|
||||
bool mschapv2_generate_authenticator_response(
|
||||
const uint8_t pw_hash_hash[static 16],
|
||||
const uint8_t nt_response[static 24],
|
||||
const uint8_t peer_challenge[static 16],
|
||||
const uint8_t server_challenge[static 16],
|
||||
const char *user, char response[static 42]);
|
||||
Loading…
Reference in New Issue
Block a user