* You should also use DOMAIN\\USERNAME as described in README.MSCHAP80
*/
-#define RCSID "$Id: chap_ms.c,v 1.17 2002/03/04 14:59:51 dfs Exp $"
+/*
+ * Modifications by Frank Cusack, frank@google.com, March 2002.
+ *
+ * Implemented MS-CHAPv2 functionality. Heavily based on
+ * sample implementation in RFC 2759.
+ */
+
+#define RCSID "$Id: chap_ms.c,v 1.18 2002/03/05 15:14:04 dfs Exp $"
#ifdef CHAPMS
#include "chap.h"
#include "chap_ms.h"
#include "md4.h"
+#include "sha1.h"
#ifndef USE_CRYPT
#include <des.h>
static const char rcsid[] = RCSID;
-static void ChallengeResponse __P((u_char *, u_char *, u_char *));
-static void DesEncrypt __P((u_char *, u_char *, u_char *));
+static void ChallengeHash __P((u_char[16], u_char *, char *, u_char[8]));
+static void ascii2unicode __P((char[], int, u_char[]));
+static void NTPasswordHash __P((char *, int, u_char[MD4_SIGNATURE_SIZE]));
+static void ChallengeResponse __P((u_char *, u_char *, u_char[24]));
+static void DesEncrypt __P((u_char *, u_char *, u_char[8]));
static void MakeKey __P((u_char *, u_char *));
static u_char Get7Bits __P((u_char *, int));
-static void ChapMS_NT __P((char *, int, char *, int, MS_ChapResponse *));
+static void ChapMS_NT __P((u_char *, char *, int, u_char[24]));
+static void ChapMS2_NT __P((char *, u_char[16], char *, char *, int,
+ u_char[24]));
+static void GenerateAuthenticatorResponse __P((char*, int, u_char[24],
+ u_char[16], u_char *,
+ char *, u_char[41]));
#ifdef MSLANMAN
-static void ChapMS_LANMan __P((char *, int, char *, int, MS_ChapResponse *));
+static void ChapMS_LANMan __P((u_char *, char *, int, MS_ChapResponse *));
#endif
#ifdef USE_CRYPT
static void Collapse __P((u_char *, u_char *));
#endif
+extern double drand48 __P((void));
+
#ifdef MSLANMAN
bool ms_lanman = 0; /* Use LanMan password instead of NT */
/* Has meaning only with MS-CHAP challenges */
#endif
static void
-ChallengeResponse(challenge, pwHash, response)
- u_char *challenge; /* IN 8 octets */
- u_char *pwHash; /* IN 16 octets */
- u_char *response; /* OUT 24 octets */
+ChallengeResponse(u_char *challenge,
+ u_char PasswordHash[MD4_SIGNATURE_SIZE],
+ u_char response[24])
{
char ZPasswordHash[21];
BZERO(ZPasswordHash, sizeof(ZPasswordHash));
- BCOPY(pwHash, ZPasswordHash, MD4_SIGNATURE_SIZE);
+ BCOPY(PasswordHash, ZPasswordHash, MD4_SIGNATURE_SIZE);
#if 0
dbglog("ChallengeResponse - ZPasswordHash %.*B",
sizeof(ZPasswordHash), ZPasswordHash);
#endif
- DesEncrypt(challenge, ZPasswordHash + 0, response + 0);
- DesEncrypt(challenge, ZPasswordHash + 7, response + 8);
- DesEncrypt(challenge, ZPasswordHash + 14, response + 16);
+ DesEncrypt(challenge, ZPasswordHash + 0, &response[0]);
+ DesEncrypt(challenge, ZPasswordHash + 7, &response[8]);
+ DesEncrypt(challenge, ZPasswordHash + 14, &response[16]);
#if 0
dbglog("ChallengeResponse - response %.24B", response);
#ifdef USE_CRYPT
static void
-DesEncrypt(clear, key, cipher)
- u_char *clear; /* IN 8 octets */
- u_char *key; /* IN 7 octets */
- u_char *cipher; /* OUT 8 octets */
+DesEncrypt(u_char *clear, u_char *key, u_char cipher[8])
{
u_char des_key[8];
u_char crypt_key[66];
#else /* USE_CRYPT */
static void
-DesEncrypt(clear, key, cipher)
- u_char *clear; /* IN 8 octets */
- u_char *key; /* IN 7 octets */
- u_char *cipher; /* OUT 8 octets */
+DesEncrypt(u_char *clear, u_char *key, u_char cipher[8])
{
des_cblock des_key;
des_key_schedule key_schedule;
#endif /* USE_CRYPT */
-static u_char Get7Bits(input, startBit)
- u_char *input;
- int startBit;
+static u_char Get7Bits(u_char *input, int startBit)
{
register unsigned int word;
* out == 64-byte string where each byte is either 1 or 0
* Note that the low-order "bit" is always ignored by by setkey()
*/
-static void Expand(in, out)
- u_char *in;
- u_char *out;
+static void Expand(u_char *in, u_char *out)
{
int j, c;
int i;
/* The inverse of Expand
*/
-static void Collapse(in, out)
- u_char *in;
- u_char *out;
+static void Collapse(u_char *in, u_char *out)
{
int j;
int i;
}
#endif
-static void MakeKey(key, des_key)
- u_char *key; /* IN 56 bit DES key missing parity bits */
- u_char *des_key; /* OUT 64 bit DES key with parity bits added */
+static void MakeKey(u_char *key, u_char *des_key)
{
des_key[0] = Get7Bits(key, 0);
des_key[1] = Get7Bits(key, 7);
#endif
}
+
static void
-ChapMS_NT(rchallenge, rchallenge_len, secret, secret_len, response)
- char *rchallenge;
- int rchallenge_len;
- char *secret;
- int secret_len;
- MS_ChapResponse *response;
+ChallengeHash(u_char PeerChallenge[16], u_char *rchallenge,
+ char *username, u_char Challenge[8])
+
+{
+ SHA1_CTX sha1Context;
+ u_char sha1Hash[SHA1_SIGNATURE_SIZE];
+
+ SHA1_Init(&sha1Context);
+ SHA1_Update(&sha1Context, PeerChallenge, 16);
+ SHA1_Update(&sha1Context, rchallenge, 16);
+ SHA1_Update(&sha1Context, username, strlen(username));
+ SHA1_Final(sha1Hash, &sha1Context);
+
+ BCOPY(sha1Hash, Challenge, 8);
+}
+
+/*
+ * Convert the ASCII version of the password to Unicode.
+ * This implicitly supports 8-bit ISO8859/1 characters.
+ * This gives us the little-endian representation, which
+ * is assumed by all M$ CHAP RFCs. (Unicode byte ordering
+ * is machine-dependent.)
+ */
+static void
+ascii2unicode(char ascii[], int ascii_len, u_char unicode[])
+{
+ int i;
+
+ BZERO(unicode, ascii_len * 2);
+ for (i = 0; i < ascii_len; i++)
+ unicode[i * 2] = (u_char) ascii[i];
+}
+
+static void
+NTPasswordHash(char *secret, int secret_len, u_char hash[MD4_SIGNATURE_SIZE])
{
- int i;
#ifdef __NetBSD__
/* NetBSD uses the libc md4 routines which take bytes instead of bits */
- int mdlen = secret_len * 2;
+ int mdlen = secret_len;
#else
- int mdlen = secret_len * 2 * 8;
+ int mdlen = secret_len * 8;
#endif
MD4_CTX md4Context;
- u_char hash[MD4_SIGNATURE_SIZE];
- u_char unicodePassword[MAX_NT_PASSWORD * 2];
-
- /* Initialize the Unicode version of the secret (== password). */
- /* This implicitly supports 8-bit ISO8859/1 characters. */
- BZERO(unicodePassword, sizeof(unicodePassword));
- for (i = 0; i < secret_len; i++)
- unicodePassword[i * 2] = (u_char)secret[i];
MD4Init(&md4Context);
- MD4Update(&md4Context, unicodePassword, mdlen);
+ MD4Update(&md4Context, secret, mdlen);
+ MD4Final(hash, &md4Context);
+
+}
+
+static void
+ChapMS_NT(u_char *rchallenge, char *secret, int secret_len,
+ u_char NTResponse[24])
+{
+ u_char unicodePassword[MAX_NT_PASSWORD * 2];
+ u_char PasswordHash[MD4_SIGNATURE_SIZE];
- MD4Final(hash, &md4Context); /* Tell MD4 we're done */
+ /* Hash the Unicode version of the secret (== password). */
+ ascii2unicode(secret, secret_len, unicodePassword);
+ NTPasswordHash(unicodePassword, secret_len * 2, PasswordHash);
- ChallengeResponse(rchallenge, hash, response->NTResp);
+ ChallengeResponse(rchallenge, PasswordHash, NTResponse);
+}
+
+static void
+ChapMS2_NT(char *rchallenge, u_char PeerChallenge[16], char *username,
+ char *secret, int secret_len, u_char NTResponse[24])
+{
+ u_char unicodePassword[MAX_NT_PASSWORD * 2];
+ u_char PasswordHash[MD4_SIGNATURE_SIZE];
+ u_char Challenge[8];
+
+ ChallengeHash(PeerChallenge, rchallenge, username, Challenge);
+
+ /* Hash the Unicode version of the secret (== password). */
+ ascii2unicode(secret, secret_len, unicodePassword);
+ NTPasswordHash(unicodePassword, secret_len * 2, PasswordHash);
+
+ ChallengeResponse(Challenge, PasswordHash, NTResponse);
}
#ifdef MSLANMAN
static u_char *StdText = (u_char *)"KGS!@#$%"; /* key from rasapi32.dll */
static void
-ChapMS_LANMan(rchallenge, rchallenge_len, secret, secret_len, response)
- char *rchallenge;
- int rchallenge_len;
- char *secret;
- int secret_len;
- MS_ChapResponse *response;
+ChapMS_LANMan(u_char *rchallenge, char *secret, int secret_len,
+ u_char LMResponse[24])
{
int i;
u_char UcasePassword[MAX_NT_PASSWORD]; /* max is actually 14 */
UcasePassword[i] = (u_char)toupper(secret[i]);
DesEncrypt( StdText, UcasePassword + 0, PasswordHash + 0 );
DesEncrypt( StdText, UcasePassword + 7, PasswordHash + 8 );
- ChallengeResponse(rchallenge, PasswordHash, response->LANManResp);
+ ChallengeResponse(rchallenge, PasswordHash, LMResponse);
}
#endif
-void
-ChapMS(cstate, rchallenge, rchallenge_len, secret, secret_len)
- chap_state *cstate;
- char *rchallenge;
- int rchallenge_len;
- char *secret;
- int secret_len;
+
+static void
+GenerateAuthenticatorResponse(char *secret, int secret_len,
+ u_char NTResponse[24], u_char PeerChallenge[16],
+ u_char *rchallenge, char *username,
+ u_char authResponse[MS_AUTH_RESPONSE_LENGTH+1])
{
- MS_ChapResponse response;
+ /*
+ * "Magic" constants used in response generation, from RFC 2759.
+ */
+ u_char Magic1[39] = /* "Magic server to client signing constant" */
+ {0x4D, 0x61, 0x67, 0x69, 0x63, 0x20, 0x73, 0x65, 0x72, 0x76,
+ 0x65, 0x72, 0x20, 0x74, 0x6F, 0x20, 0x63, 0x6C, 0x69, 0x65,
+ 0x6E, 0x74, 0x20, 0x73, 0x69, 0x67, 0x6E, 0x69, 0x6E, 0x67,
+ 0x20, 0x63, 0x6F, 0x6E, 0x73, 0x74, 0x61, 0x6E, 0x74};
+ u_char Magic2[41] = /* "Pad to make it do more than one iteration" */
+ {0x50, 0x61, 0x64, 0x20, 0x74, 0x6F, 0x20, 0x6D, 0x61, 0x6B,
+ 0x65, 0x20, 0x69, 0x74, 0x20, 0x64, 0x6F, 0x20, 0x6D, 0x6F,
+ 0x72, 0x65, 0x20, 0x74, 0x68, 0x61, 0x6E, 0x20, 0x6F, 0x6E,
+ 0x65, 0x20, 0x69, 0x74, 0x65, 0x72, 0x61, 0x74, 0x69, 0x6F,
+ 0x6E};
+
+ int i;
+ SHA1_CTX sha1Context;
+ u_char unicodePassword[MAX_NT_PASSWORD * 2];
+ u_char PasswordHash[MD4_SIGNATURE_SIZE];
+ u_char PasswordHashHash[MD4_SIGNATURE_SIZE];
+ u_char Digest[SHA1_SIGNATURE_SIZE];
+ u_char Challenge[8];
+
+ /* Hash (x2) the Unicode version of the secret (== password). */
+ ascii2unicode(secret, secret_len, unicodePassword);
+ NTPasswordHash(unicodePassword, secret_len * 2, PasswordHash);
+ NTPasswordHash(PasswordHash, sizeof(PasswordHash), PasswordHashHash);
+
+ SHA1_Init(&sha1Context);
+ SHA1_Update(&sha1Context, PasswordHashHash, sizeof(PasswordHashHash));
+ SHA1_Update(&sha1Context, NTResponse, 24);
+ SHA1_Update(&sha1Context, Magic1, sizeof(Magic1));
+ SHA1_Final(Digest, &sha1Context);
+
+ ChallengeHash(PeerChallenge, rchallenge, username, Challenge);
+
+ SHA1_Init(&sha1Context);
+ SHA1_Update(&sha1Context, Digest, sizeof(Digest));
+ SHA1_Update(&sha1Context, Challenge, sizeof(Challenge));
+ SHA1_Update(&sha1Context, Magic2, sizeof(Magic2));
+ SHA1_Final(Digest, &sha1Context);
+
+ /* Convert to ASCII hex string. */
+ for (i = 0; i < MAX((MS_AUTH_RESPONSE_LENGTH / 2), sizeof(Digest)); i++)
+ sprintf(&authResponse[i * 2], "%02X", Digest[i]);
+}
+
+void
+ChapMS(chap_state *cstate, u_char *rchallenge, char *secret, int secret_len,
+ MS_ChapResponse *response)
+{
#if 0
CHAPDEBUG((LOG_INFO, "ChapMS: secret is '%.*s'", secret_len, secret));
#endif
- BZERO(&response, sizeof(response));
+ BZERO(response, sizeof(response));
/* Calculate both always */
- ChapMS_NT(rchallenge, rchallenge_len, secret, secret_len, &response);
+ ChapMS_NT(rchallenge, secret, secret_len, response->NTResp);
#ifdef MSLANMAN
- ChapMS_LANMan(rchallenge, rchallenge_len, secret, secret_len, &response);
+ ChapMS_LANMan(rchallenge, secret, secret_len, response);
/* prefered method is set by option */
- response.UseNT[0] = !ms_lanman;
+ response->UseNT[0] = !ms_lanman;
#else
- response.UseNT[0] = 1;
+ response->UseNT[0] = 1;
#endif
- BCOPY(&response, cstate->response, MS_CHAP_RESPONSE_LEN);
- cstate->resp_length = MS_CHAP_RESPONSE_LEN;
}
+
+/*
+ * If PeerChallenge is NULL, one is generated and response->PeerChallenge
+ * is filled in. Call this way when generating a response.
+ * If PeerChallenge is supplied, it is copied into response->PeerChallenge.
+ * Call this way when verifying a response.
+ *
+ * response->PeerChallenge is then used for calculation of the
+ * Authenticator Response.
+ */
+void
+ChapMS2(chap_state *cstate, u_char *rchallenge, u_char *PeerChallenge,
+ char *user, char *secret, int secret_len, MS_Chap2Response *response,
+ u_char authResponse[MS_AUTH_RESPONSE_LENGTH+1])
+{
+ u_char *p = response->PeerChallenge;
+ int i;
+
+ BZERO(response, sizeof(response));
+
+ /* Generate the Peer-Challenge if requested, or copy it if supplied. */
+ if (!PeerChallenge)
+ for (i = 0; i < sizeof(response->PeerChallenge); i++)
+ *p++ = (u_char) (drand48() * 0xff);
+ else
+ BCOPY(PeerChallenge, response->PeerChallenge,
+ sizeof(response->PeerChallenge));
+
+ /* Generate the NT-Response */
+ ChapMS2_NT(rchallenge, response->PeerChallenge, user,
+ secret, secret_len, response->NTResp);
+
+ /* Generate the Authenticator Response. */
+ GenerateAuthenticatorResponse(secret, secret_len, response->NTResp,
+ response->PeerChallenge, rchallenge,
+ user, authResponse);
+}
+
+
#endif /* CHAPMS */
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