* Implemented EAP-TLS authentication
*/
-/*
- * TODO:
- */
-
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef USE_EAPTLS
#include "eap-tls.h"
#endif /* USE_EAPTLS */
+
#ifdef CHAPMS
-#include "magic.h"
#include "chap_ms.h"
#include "chap-new.h"
#endif /* CHAPMS */
#ifdef USE_EAPTLS
esp->es_client.ea_using_eaptls = 0;
#endif /* USE_EAPTLS */
+#ifdef CHAPMS
+ esp->es_client.digest = chap_find_digest(CHAP_MICROSOFT_V2);
+ esp->es_server.digest = chap_find_digest(CHAP_MICROSOFT_V2);
+#endif
}
/*
}
#if CHAPMS
-static int
-eap_chapms2_verify_response(int id, char *name,
- unsigned char *secret, int secret_len,
- unsigned char *challenge, unsigned char *response,
- char *message, int message_space)
-{
- unsigned char md[MS_CHAP2_RESPONSE_LEN];
- char saresponse[MS_AUTH_RESPONSE_LENGTH+1];
- int challenge_len, response_len;
-
- challenge_len = *challenge++; /* skip length, is 16 */
- response_len = *response++;
- if (response_len != MS_CHAP2_RESPONSE_LEN)
- goto bad; /* not even the right length */
-
- /* Generate the expected response and our mutual auth. */
- ChapMS2(challenge, &response[MS_CHAP2_PEER_CHALLENGE], name,
- (char *)secret, secret_len, md,
- (unsigned char *)saresponse, MS_CHAP2_AUTHENTICATOR);
-
- /* compare MDs and send the appropriate status */
- /*
- * 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.
- */
- if (memcmp(&md[MS_CHAP2_NTRESP], &response[MS_CHAP2_NTRESP],
- MS_CHAP2_NTRESP_LEN) == 0) {
- if (response[MS_CHAP2_FLAGS])
- slprintf(message, message_space, "S=%s", saresponse);
- else
- slprintf(message, message_space, "S=%s M=%s",
- saresponse, "Access granted");
- return 1;
- }
-
- bad:
- /*
- * 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. 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(message, message_space, "E=691 R=1 C=%0.*B V=0 M=%s",
- challenge_len, challenge, "Access denied");
- return 0;
-}
-
-static struct chap_digest_type eap_chapms2_digest = {
- CHAP_MICROSOFT_V2, /* code */
- NULL, /* chapms2_generate_challenge, */
- eap_chapms2_verify_response,
- NULL, /* chapms2_make_response, */
- NULL, /* chapms2_check_success, */
- NULL, /* chapms_handle_failure, */
-};
-
/*
* eap_chap_verify_response - check whether the peer's response matches
* what we think it should be. Returns 1 if it does (authentication
#ifdef CHAPMS
case eapMSCHAPv2Chall:
- challen = 0x10;
+ esp->es_server.digest->generate_challenge(esp->es_challenge);
+ challen = esp->es_challenge[0];
esp->es_challen = challen;
- esp->es_challenge[0] = challen;
- random_bytes(&esp->es_challenge[1], challen);
PUTCHAR(EAPT_MSCHAPV2, outp);
PUTCHAR(CHAP_CHALLENGE, outp);
}
#endif /* USE_SRP */
+#if CHAPMS
+/*
+ * Format and send an CHAPV2-Challenge EAP Response message.
+ */
+static void
+eap_chapv2_response(eap_state *esp, u_char id, u_char chapid, u_char *response, char *user, int user_len)
+{
+ u_char *outp;
+ int msglen;
+
+ outp = outpacket_buf;
+
+ MAKEHEADER(outp, PPP_EAP);
+
+ PUTCHAR(EAP_RESPONSE, outp);
+ PUTCHAR(id, outp);
+ esp->es_client.ea_id = id;
+ msglen = EAP_HEADERLEN + 6 * sizeof (u_char) + MS_CHAP2_RESPONSE_LEN + user_len;
+ PUTSHORT(msglen, outp);
+ PUTCHAR(EAPT_MSCHAPV2, outp);
+ PUTCHAR(CHAP_RESPONSE, outp);
+ PUTCHAR(chapid, outp);
+ PUTCHAR(0, outp);
+ /* len */
+ PUTCHAR(5 + user_len + MS_CHAP2_RESPONSE_LEN, outp);
+ BCOPY(response, outp, MS_CHAP2_RESPONSE_LEN+1); // VLEN + VALUE
+ INCPTR(MS_CHAP2_RESPONSE_LEN+1, outp);
+ BCOPY(user, outp, user_len);
+
+ output(esp->es_unit, outpacket_buf, PPP_HDRLEN + msglen);
+}
+#endif
+
/*
* eap_request - Receive EAP Request message (client mode).
*/
/* Init ssl session */
if(!eaptls_init_ssl_client(esp)) {
dbglog("cannot init ssl");
- eap_send_nak(esp, id, EAPT_TLS);
+ eap_send_nak(esp, id, EAPT_MSCHAPV2);
esp->es_client.ea_using_eaptls = 0;
break;
}
}
/* The server has sent a bad start packet. */
- eap_send_nak(esp, id, EAPT_TLS);
+ eap_send_nak(esp, id, EAPT_MSCHAPV2);
break;
case eapTlsRecvAck:
break;
default:
- eap_send_nak(esp, id, EAPT_TLS);
+ eap_send_nak(esp, id, EAPT_MSCHAPV2);
esp->es_client.ea_using_eaptls = 0;
break;
}
}
break;
#endif /* USE_SRP */
+
+#ifdef CHAPMS
+ case EAPT_MSCHAPV2:
+ if (len < 4) {
+ error("EAP: received invalid MSCHAPv2 packet, too short");
+ return;
+ }
+ unsigned char opcode;
+ GETCHAR(opcode, inp);
+ unsigned char chapid; /* Chapv2-ID */
+ GETCHAR(chapid, inp);
+ short mssize;
+ GETSHORT(mssize, inp);
+
+ /* Validate the mssize field */
+ if (len != mssize) {
+ error("EAP: received invalid MSCHAPv2 packet, invalid length");
+ return;
+ }
+ len -= 4;
+
+ /* If MSCHAPv2 digest was not found, NAK the packet */
+ if (!esp->es_client.digest) {
+ error("EAP MSCHAPv2 not supported");
+ eap_send_nak(esp, id, EAPT_SRP);
+ return;
+ }
+
+ switch (opcode) {
+ case CHAP_CHALLENGE: {
+
+ /* make_response() expects: VLEN + VALUE */
+ u_char *challenge = inp;
+
+ unsigned char vsize;
+ GETCHAR(vsize, inp);
+ len -= 1;
+
+ /* Validate the VALUE field */
+ if (vsize != MS_CHAP2_PEER_CHAL_LEN || len < MS_CHAP2_PEER_CHAL_LEN) {
+ error("EAP: received invalid MSCHAPv2 packet, invalid value-length: %d", vsize);
+ return;
+ }
+
+ /* Increment past the VALUE field */
+ INCPTR(MS_CHAP2_PEER_CHAL_LEN, inp);
+ len -= MS_CHAP2_PEER_CHAL_LEN;
+
+ /* Extract the hostname */
+ rhostname[0] = '\0';
+ if (len > 0) {
+ if (len >= sizeof (rhostname)) {
+ dbglog("EAP: trimming really long peer name down");
+ len = sizeof(rhostname) - 1;
+ }
+ BCOPY(inp, rhostname, len);
+ rhostname[len] = '\0';
+ }
+
+ /* In case the remote doesn't give us his name. */
+ if (explicit_remote || (remote_name[0] != '\0' && len == 0))
+ strlcpy(rhostname, remote_name, sizeof(rhostname));
+
+ /* Get the secret for authenticating ourselves with the specified host. */
+ if (!get_secret(esp->es_unit, esp->es_client.ea_name,
+ rhostname, secret, &secret_len, 0)) {
+ dbglog("EAP: no CHAP secret for auth to %q", rhostname);
+ eap_send_nak(esp, id, EAPT_SRP);
+ break;
+ }
+
+ /* Create the MSCHAPv2 response (and add to cache) */
+ unsigned char response[MS_CHAP2_RESPONSE_LEN+1]; // VLEN + VALUE
+ esp->es_client.digest->make_response(response, chapid, esp->es_client.ea_name,
+ challenge, secret, secret_len, NULL);
+
+ eap_chapv2_response(esp, id, chapid, response, esp->es_client.ea_name, esp->es_client.ea_namelen);
+ break;
+ }
+ case CHAP_SUCCESS: {
+
+ /* Check response for mutual authentication */
+ u_char status = CHAP_FAILURE;
+ if (esp->es_client.digest->check_success(chapid, inp, len) == 1) {
+ info("Chap authentication succeeded! %.*v", len, inp);
+ status = CHAP_SUCCESS;
+ }
+ eap_send_response(esp, id, EAPT_MSCHAPV2, &status, sizeof(status));
+ break;
+ }
+ case CHAP_FAILURE: {
+
+ /* Process the failure string, and log appropriate information */
+ esp->es_client.digest->handle_failure(inp, len);
+
+ u_char status = CHAP_FAILURE;
+ eap_send_response(esp, id, EAPT_MSCHAPV2, &status, sizeof(status));
+ goto client_failure; /* force termination */
+ }
+ default:
+
+ error("EAP: received invalid MSCHAPv2 packet, invalid or unsupported opcode: %d", opcode);
+ eap_send_nak(esp, id, EAPT_SRP);
+ }
+
+ break;
+#endif /* CHAPMS */
default:
info("EAP: unknown authentication type %d; Naking", typenum);
}
return;
-#ifdef USE_SRP
client_failure:
esp->es_client.ea_state = eapBadAuth;
if (esp->es_client.ea_timeout > 0) {
UNTIMEOUT(eap_client_timeout, (void *)esp);
}
esp->es_client.ea_session = NULL;
+#ifdef USE_SRP
t_clientclose(tc);
auth_withpeer_fail(esp->es_unit, PPP_EAP);
#endif /* USE_SRP */
#ifdef CHAPMS
case EAPT_MSCHAPV2:
info("EAP: peer proposes MSCHAPv2");
+ /* If MSCHAPv2 digest was not found, NAK the packet */
+ if (!esp->es_server.digest) {
+ error("EAP MSCHAPv2 not supported");
+ eap_send_nak(esp, id, EAPT_SRP);
+ break;
+ }
esp->es_server.ea_state = eapMSCHAPv2Chall;
break;
#endif /* CHAPMS */
if ((*chap_verifier)(rhostname,
esp->es_server.ea_name,
id,
- &eap_chapms2_digest,
+ esp->es_server.digest,
esp->es_challenge,
inp - 1,
response_message,
len--;
printer(arg, " <Suggested-type %02X", rtype);
if (rtype >= 1 &&
- rtype < sizeof (eap_typenames) / sizeof (char *))
+ rtype <= sizeof (eap_typenames) / sizeof (char *))
printer(arg, " (%s)", eap_typenames[rtype-1]);
printer(arg, ">");
break;
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