/*
- * chap_ms.c - Challenge Handshake Authentication Protocol.
+ * chap.c - Challenge Handshake Authentication Protocol.
*
- * Copyright (c) 1993 The Australian National University.
- * All rights reserved.
+ * Copyright (c) 1993-2002 Paul Mackerras. All rights reserved.
*
- * Redistribution and use in source and binary forms are permitted
- * provided that the above copyright notice and this paragraph are
- * duplicated in all such forms and that any documentation,
- * advertising materials, and other materials related to such
- * distribution and use acknowledge that the software was developed
- * by the Australian National University. The name of the University
- * may not be used to endorse or promote products derived from this
- * software without specific prior written permission.
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
- * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ * 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. The name(s) of the authors of this software must not be used to
+ * endorse or promote products derived from this software without
+ * prior written permission.
+ *
+ * 4. Redistributions of any form whatsoever must retain the following
+ * acknowledgment:
+ * "This product includes software developed by Paul Mackerras
+ * <paulus@samba.org>".
+ *
+ * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
+ * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
+ * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
+ * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* Copyright (c) 1991 Gregory M. Christy.
* All rights reserved.
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
-#define RCSID "$Id: chap.c,v 1.27 2002/03/01 14:39:18 dfs Exp $"
+#define RCSID "$Id: chap.c,v 1.38 2002/12/04 23:03:32 paulus Exp $"
/*
* TODO:
*/
#include <stdio.h>
+#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/time.h>
static const char rcsid[] = RCSID;
+#ifdef CHAPMS
+/* For MPPE debug */
+/* Use "[]|}{?/><,`!2&&(" (sans quotes) for RFC 3079 MS-CHAPv2 test value */
+static char *mschap_challenge = NULL;
+/* Use "!@\#$%^&*()_+:3|~" (sans quotes, backslash is to escape #) for ... */
+static char *mschap2_peer_challenge = NULL;
+#endif
+
/*
* Command-line options.
*/
#ifdef MSLANMAN
{ "ms-lanman", o_bool, &ms_lanman,
"Use LanMan passwd when using MS-CHAP", 1 },
+#endif
+#ifdef DEBUGMPPEKEY
+ { "mschap-challenge", o_string, &mschap_challenge,
+ "specify CHAP challenge" },
+ { "mschap2-peer-challenge", o_string, &mschap2_peer_challenge,
+ "specify CHAP peer challenge" },
#endif
{ NULL }
};
rchallenge = inp;
INCPTR(rchallenge_len, inp);
- if (len >= sizeof(rhostname))
- len = sizeof(rhostname) - 1;
- BCOPY(inp, rhostname, len);
- rhostname[len] = '\000';
+ /* Null terminate and clean remote name. */
+ slprintf(rhostname, sizeof(rhostname), "%.*v", len, inp);
/* Microsoft doesn't send their name back in the PPP packet */
if (explicit_remote || (remote_name[0] != 0 && rhostname[0] == 0)) {
#ifdef CHAPMS
case CHAP_MICROSOFT:
- ChapMS(cstate, rchallenge, rchallenge_len, secret, secret_len);
+ ChapMS(cstate, rchallenge, secret, secret_len,
+ (MS_ChapResponse *) cstate->response);
break;
-#endif
+
+ case CHAP_MICROSOFT_V2:
+ ChapMS2(cstate, rchallenge,
+ mschap2_peer_challenge? mschap2_peer_challenge: NULL,
+ cstate->resp_name, secret, secret_len,
+ (MS_Chap2Response *) cstate->response, cstate->earesponse,
+ MS_CHAP2_AUTHENTICATEE);
+ break;
+#endif /* CHAPMS */
default:
CHAPDEBUG(("unknown digest type %d", cstate->resp_type));
UNTIMEOUT(ChapChallengeTimeout, cstate);
- if (len >= sizeof(rhostname))
- len = sizeof(rhostname) - 1;
- BCOPY(inp, rhostname, len);
- rhostname[len] = '\000';
+ /* Null terminate and clean remote name. */
+ slprintf(rhostname, sizeof(rhostname), "%.*v", len, inp);
+#ifdef CHAPMS
+ /* copy the flags into cstate for use elsewhere */
+ if (cstate->chal_type == CHAP_MICROSOFT_V2)
+ cstate->resp_flags = ((MS_Chap2Response *) remmd)->Flags[0];
+#endif /* CHAPMS */
/*
* Get secret for authenticating them with us,
* do the hash ourselves, and compare the result.
code = (*chap_auth_hook) ( (explicit_remote ? remote_name : rhostname),
remmd, (int) remmd_len,
cstate );
+ /*
+ * Check remote number authorization. A plugin may have filled in
+ * the remote number or added an allowed number, and rather than
+ * return an authenticate failure, is leaving it for us to verify.
+ */
+ if (code == CHAP_SUCCESS) {
+ if (!auth_number()) {
+ /* We do not want to leak info about the chap result. */
+ code = CHAP_FAILURE; /* XXX exit value will be "wrong" */
+ warn("calling number %q is not authorized", remote_number);
+ }
+ }
+
} else {
if (!get_secret(cstate->unit, (explicit_remote? remote_name: rhostname),
cstate->chal_name, secret, &secret_len, 1)) {
MD5Final(hash, &mdContext);
/* compare MDs and send the appropriate status */
- if (memcmp (hash, remmd, MD5_SIGNATURE_SIZE) == 0)
+ if (memcmp(hash, remmd, MD5_SIGNATURE_SIZE) == 0)
code = CHAP_SUCCESS; /* they are the same! */
break;
case CHAP_MICROSOFT:
{
int response_offset, response_size;
+ MS_ChapResponse *rmd = (MS_ChapResponse *) remmd;
+ MS_ChapResponse md;
if (remmd_len != MS_CHAP_RESPONSE_LEN)
break; /* not even the right length */
- ChapMS(cstate, cstate->challenge, cstate->chal_len,
- secret, secret_len);
/* Determine which part of response to verify against */
- if ((u_char *) (remmd + offsetof(MS_ChapResponse, UseNT))) {
+ if (rmd->UseNT[0]) {
response_offset = offsetof(MS_ChapResponse, NTResp);
- response_size = sizeof(((MS_ChapResponse *) remmd)->NTResp);
+ response_size = sizeof(rmd->NTResp);
} else {
+#ifdef MSLANMAN
response_offset = offsetof(MS_ChapResponse, LANManResp);
- response_size =
- sizeof(((MS_ChapResponse *) remmd)->LANManResp);
+ response_size = sizeof(rmd->LANManResp);
+#else
+ /* Should really propagate this into the error packet. */
+ notice("Peer request for LANMAN auth not supported");
+ break;
+#endif /* MSLANMAN */
}
+ /* Generate the expected response. */
+ ChapMS(cstate, cstate->challenge, secret, secret_len, &md);
+
/* compare MDs and send the appropriate status */
- if (memcmp(cstate->response + response_offset,
- remmd + response_offset, response_size) == 0)
+ if (memcmp((u_char *) &md + response_offset,
+ (u_char *) remmd + response_offset,
+ response_size) == 0)
code = CHAP_SUCCESS; /* they are the same! */
break;
}
+
+ case CHAP_MICROSOFT_V2:
+ {
+ MS_Chap2Response *rmd = (MS_Chap2Response *) remmd;
+ MS_Chap2Response md;
+
+ if (remmd_len != MS_CHAP2_RESPONSE_LEN)
+ break; /* not even the right length */
+
+ /* Generate the expected response and our mutual auth. */
+ ChapMS2(cstate, cstate->challenge, rmd->PeerChallenge,
+ (explicit_remote? remote_name: rhostname),
+ secret, secret_len, &md,
+ cstate->saresponse, MS_CHAP2_AUTHENTICATOR);
+
+ /* compare MDs and send the appropriate status */
+ if (memcmp(md.NTResp, rmd->NTResp, sizeof(md.NTResp)) == 0)
+ code = CHAP_SUCCESS; /* yay! */
+ break;
+ }
#endif /* CHAPMS */
default:
old_state = cstate->serverstate;
cstate->serverstate = CHAPSS_OPEN;
if (old_state == CHAPSS_INITIAL_CHAL) {
- auth_peer_success(cstate->unit, PPP_CHAP, rhostname, len);
+ auth_peer_success(cstate->unit, PPP_CHAP, cstate->chal_type,
+ rhostname, len);
}
if (cstate->chal_interval != 0)
TIMEOUT(ChapRechallenge, cstate, cstate->chal_interval);
notice("CHAP peer authentication succeeded for %q", rhostname);
} else {
- error("CHAP peer authentication failed for remote host %q", rhostname);
+ warn("CHAP peer authentication failed for %q", rhostname);
cstate->serverstate = CHAPSS_BADAUTH;
auth_peer_fail(cstate->unit, PPP_CHAP);
}
UNTIMEOUT(ChapResponseTimeout, cstate);
+#ifdef CHAPMS
+ /*
+ * For MS-CHAPv2, we must verify that the peer knows our secret.
+ */
+ if (cstate->resp_type == CHAP_MICROSOFT_V2) {
+ if ((len >= MS_AUTH_RESPONSE_LENGTH + 2) && !strncmp(inp, "S=", 2)) {
+ inp += 2; len -= 2;
+ if (!memcmp(inp, cstate->earesponse, MS_AUTH_RESPONSE_LENGTH)) {
+ /* Authenticator Response matches. */
+ inp += MS_AUTH_RESPONSE_LENGTH; /* Eat it */
+ len -= MS_AUTH_RESPONSE_LENGTH;
+ if ((len >= 3) && !strncmp(inp, " M=", 3)) {
+ inp += 3; len -= 3; /* Eat the delimiter */
+ } else if (len) {
+ /* Packet has extra text which does not begin " M=" */
+ error("MS-CHAPv2 Success packet is badly formed.");
+ auth_withpeer_fail(cstate->unit, PPP_CHAP);
+ }
+ } else {
+ /* Authenticator Response did not match expected. */
+ error("MS-CHAPv2 mutual authentication failed.");
+ auth_withpeer_fail(cstate->unit, PPP_CHAP);
+ }
+ } else {
+ /* Packet does not start with "S=" */
+ error("MS-CHAPv2 Success packet is badly formed.");
+ auth_withpeer_fail(cstate->unit, PPP_CHAP);
+ }
+ }
+#endif
+
/*
* Print message.
*/
cstate->clientstate = CHAPCS_OPEN;
- auth_withpeer_success(cstate->unit, PPP_CHAP);
+ notice("CHAP authentication succeeded");
+ auth_withpeer_success(cstate->unit, PPP_CHAP, cstate->resp_type);
}
u_char id;
int len;
{
+ u_char *msg;
+ u_char *p = inp;
+
if (cstate->clientstate != CHAPCS_RESPONSE) {
/* don't know what this is */
CHAPDEBUG(("ChapReceiveFailure: in state %d\n", cstate->clientstate));
return;
}
+#ifdef CHAPMS
+ /* We want a null-terminated string for strxxx(). */
+ msg = malloc(len + 1);
+ if (!msg) {
+ p = NULL;
+ notice("Out of memory in ChapReceiveFailure");
+ goto print_msg;
+ }
+ BCOPY(inp, msg, len);
+ p = msg + len; *p = '\0'; p = msg;
+#endif
+
UNTIMEOUT(ChapResponseTimeout, cstate);
+#ifdef CHAPMS
+ if ((cstate->resp_type == CHAP_MICROSOFT_V2) ||
+ (cstate->resp_type == CHAP_MICROSOFT)) {
+ int error;
+
+ /*
+ * Deal with MS-CHAP formatted failure messages; just print the
+ * M=<message> part (if any). For MS-CHAP we're not really supposed
+ * to use M=<message>, but it shouldn't hurt. See ChapSendStatus().
+ */
+ if (!strncmp(p, "E=", 2))
+ error = (int) strtol(p, NULL, 10); /* Remember the error code. */
+ else
+ goto print_msg; /* Message is badly formatted. */
+
+ if (len && ((p = strstr(p, " M=")) != NULL)) {
+ /* M=<message> field found. */
+ p += 3;
+ } else {
+ /* No M=<message>; use the error code. */
+ switch(error) {
+ case MS_CHAP_ERROR_RESTRICTED_LOGON_HOURS:
+ p = "E=646 Restricted logon hours";
+ break;
+
+ case MS_CHAP_ERROR_ACCT_DISABLED:
+ p = "E=647 Account disabled";
+ break;
+
+ case MS_CHAP_ERROR_PASSWD_EXPIRED:
+ p = "E=648 Password expired";
+ break;
+
+ case MS_CHAP_ERROR_NO_DIALIN_PERMISSION:
+ p = "E=649 No dialin permission";
+ break;
+
+ case MS_CHAP_ERROR_AUTHENTICATION_FAILURE:
+ p = "E=691 Authentication failure";
+ break;
+
+ case MS_CHAP_ERROR_CHANGING_PASSWORD:
+ /* Should never see this, we don't support Change Password. */
+ p = "E=709 Error changing password";
+ break;
+
+ default:
+ free(msg);
+ p = msg = malloc(len + 33);
+ if (!msg) {
+ novm("ChapReceiveFailure");
+ goto print_msg;
+ }
+ slprintf(p, len + 33, "Unknown authentication failure: %.*s",
+ len, inp);
+ break;
+ }
+ }
+ len = strlen(p);
+ }
+#endif
+
/*
* Print message.
*/
- if (len > 0)
- PRINTMSG(inp, len);
+print_msg:
+ if (len > 0 && p != NULL)
+ PRINTMSG(p, len);
error("CHAP authentication failed");
auth_withpeer_fail(cstate->unit, PPP_CHAP);
+#ifdef CHAPMS
+ if (msg) free(msg);
+#endif
}
/*
* ChapSendStatus - Send a status response (ack or nak).
+ * See RFC 2433 and RFC 2759 for MS-CHAP and MS-CHAPv2 message formats.
*/
static void
ChapSendStatus(cstate, code)
int code;
{
u_char *outp;
- int outlen, msglen;
+ int i, outlen, msglen;
char msg[256];
+ char *p, *q;
- if (code == CHAP_SUCCESS)
- slprintf(msg, sizeof(msg), "Welcome to %s.", hostname);
- else
- slprintf(msg, sizeof(msg), "I don't like you. Go 'way.");
+ p = msg;
+ q = p + sizeof(msg); /* points 1 byte past msg */
+
+ if (code == CHAP_SUCCESS) {
+#ifdef CHAPMS
+ if (cstate->chal_type == CHAP_MICROSOFT_V2) {
+ /*
+ * Per RFC 2759, success message must be formatted as
+ * "S=<auth_string> M=<message>"
+ * where
+ * <auth_string> is the Authenticator Response (mutual auth)
+ * <message> is a text message
+ *
+ * However, some versions of Windows (win98 tested) do not know
+ * about the M=<message> part (required per RFC 2759) and flag
+ * it as an error (reported incorrectly as an encryption error
+ * to the user). Since the RFC requires it, and it can be
+ * useful information, we supply it if the peer is a conforming
+ * system. Luckily (?), win98 sets the Flags field to 0x04
+ * (contrary to RFC requirements) so we can use that to
+ * distinguish between conforming and non-conforming systems.
+ *
+ * Special thanks to Alex Swiridov <say@real.kharkov.ua> for
+ * help debugging this.
+ */
+ slprintf(p, q - p, "S=");
+ p += 2;
+ slprintf(p, q - p, "%s", cstate->saresponse);
+ p += strlen(cstate->saresponse);
+ if (cstate->resp_flags != 0)
+ goto msgdone;
+ slprintf(p, q - p, " M=");
+ p += 3;
+ }
+#endif /* CHAPMS */
+
+ slprintf(p, q - p, "Welcome to %s.", hostname);
+ } else {
+#ifdef CHAPMS
+ if ((cstate->chal_type == CHAP_MICROSOFT_V2) ||
+ (cstate->chal_type == CHAP_MICROSOFT)) {
+ /*
+ * Failure message must be formatted as
+ * "E=e R=r C=c V=v M=m"
+ * where
+ * e = error code (we use 691, ERROR_AUTHENTICATION_FAILURE)
+ * r = retry (we use 1, ok to retry)
+ * c = challenge to use for next response, we reuse previous
+ * v = Change Password version supported, we use 0
+ * m = text message
+ *
+ * The M=m part is only for MS-CHAPv2, but MS-CHAP should ignore
+ * any extra text according to RFC 2433. So we'll go the easy
+ * (read: lazy) route and include it always. Neither win2k nor
+ * win98 (others untested) display the message to the user anyway.
+ * They also both ignore the E=e code.
+ *
+ * Note that it's safe to reuse the same challenge as we don't
+ * actually accept another response based on the error message
+ * (and no clients try to resend a response anyway).
+ *
+ * Basically, this whole bit is useless code, even the small
+ * implementation here is only because of overspecification.
+ */
+ slprintf(p, q - p, "E=691 R=1 C=");
+ p += 12;
+ for (i = 0; i < cstate->chal_len; i++)
+ sprintf(p + i * 2, "%02X", cstate->challenge[i]);
+ p += cstate->chal_len * 2;
+ slprintf(p, q - p, " V=0 M=");
+ p += 7;
+ }
+#endif /* CHAPMS */
+
+ slprintf(p, q - p, "I don't like you. Go 'way.");
+ }
+msgdone:
msglen = strlen(msg);
outlen = CHAP_HEADERLEN + msglen;
/* MS-CHAP is fixed to an 8 octet challenge. */
chal_len = 8;
break;
+
+ case CHAP_MICROSOFT_V2:
+ /* MS-CHAPv2 is fixed to a 16 octet challenge. */
+ chal_len = 16;
+ break;
#endif
default:
fatal("ChapGenChallenge: Unsupported challenge type %d",
cstate->chal_id = ++cstate->id;
cstate->chal_transmits = 0;
- /* generate a random string */
- for (i = 0; i < chal_len; i++)
- *ptr++ = (char) (drand48() * 0xff);
+#ifdef CHAPMS
+ if (mschap_challenge)
+ for (i = 0; i < chal_len; i++)
+ *ptr++ = mschap_challenge[i];
+ else
+#endif
+ /* generate a random string */
+ for (i = 0; i < chal_len; i++)
+ *ptr++ = (char) (drand48() * 0xff);
}
/*