Patch from Frank Cusack to add support for MSCHAPv2.

[ppp.git] / pppd / chap.c

diff --git a/pppd/chap.c b/pppd/chap.c
index 208a144fc8569051fbf18f2925c8aa93daf0449b..21b0280323577b5bc10896237a5bb267248a7729 100644 (file)
--- a/pppd/chap.c
+++ b/pppd/chap.c
@@ -33,13 +33,14 @@
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  */
 
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  */
 

-#define RCSID  "$Id: chap.c,v 1.28 2002/03/04 14:59:51 dfs Exp $"
+#define RCSID  "$Id: chap.c,v 1.29 2002/03/05 15:14:04 dfs Exp $"

 
 /*
  * TODO:
  */
 
 #include <stdio.h>
 
 /*
  * TODO:
  */
 
 #include <stdio.h>

+#include <stdlib.h>

 #include <string.h>
 #include <sys/types.h>
 #include <sys/time.h>
 #include <string.h>
 #include <sys/types.h>
 #include <sys/time.h>


@@ -483,9 +484,17 @@ ChapReceiveChallenge(cstate, inp, id, len)
 
 #ifdef CHAPMS
     case CHAP_MICROSOFT:
 
 #ifdef CHAPMS
     case CHAP_MICROSOFT:

-       ChapMS(cstate, rchallenge, rchallenge_len, secret, secret_len);
+       ChapMS(cstate, rchallenge, secret, secret_len,
+              (MS_ChapResponse *) cstate->response);
+       cstate->resp_length = MS_CHAP_RESPONSE_LEN;

        break;
        break;

-#endif
+
+    case CHAP_MICROSOFT_V2:
+       ChapMS2(cstate, rchallenge, NULL, cstate->resp_name, secret, secret_len,
+               (MS_Chap2Response *) cstate->response, cstate->earesponse);
+       cstate->resp_length = MS_CHAP2_RESPONSE_LEN;
+       break;
+#endif /* CHAPMS */

 
     default:
        CHAPDEBUG(("unknown digest type %d", cstate->resp_type));
 
     default:
        CHAPDEBUG(("unknown digest type %d", cstate->resp_type));


@@ -589,7 +598,7 @@ ChapReceiveResponse(cstate, inp, id, len)
                MD5Final(hash, &mdContext);
 
                /* compare MDs and send the appropriate status */
                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;
 
                    code = CHAP_SUCCESS;        /* they are the same! */
                break;
 


@@ -598,27 +607,55 @@ ChapReceiveResponse(cstate, inp, id, len)
            {
                int response_offset, response_size;
                MS_ChapResponse *rmd = (MS_ChapResponse *) remmd;
            {
                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 */
 
                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 (rmd->UseNT[0]) {
                    response_offset = offsetof(MS_ChapResponse, NTResp);
                    response_size = sizeof(rmd->NTResp);
                } else {
 
                /* Determine which part of response to verify against */
                if (rmd->UseNT[0]) {
                    response_offset = offsetof(MS_ChapResponse, NTResp);
                    response_size = sizeof(rmd->NTResp);
                } else {

+#ifdef MSLANMAN

                    response_offset = offsetof(MS_ChapResponse, LANManResp);
                    response_size = sizeof(rmd->LANManResp);
                    response_offset = offsetof(MS_ChapResponse, 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 */
                /* compare MDs and send the appropriate status */

-               if (memcmp(cstate->response + response_offset,
-                   remmd + response_offset, response_size) == 0)
+               if (memcmp(&md + response_offset,
+                          remmd + response_offset, response_size) == 0)

                    code = CHAP_SUCCESS;        /* they are the same! */
                break;
            }
                    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);
+
+               /* 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:
 #endif /* CHAPMS */
 
            default:


@@ -670,6 +707,37 @@ ChapReceiveSuccess(cstate, inp, id, len)
 
     UNTIMEOUT(ChapResponseTimeout, cstate);
 
 
     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.
      */
     /*
      * Print message.
      */


@@ -692,22 +760,103 @@ ChapReceiveFailure(cstate, inp, id, len)
     u_char id;
     int len;
 {
     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;
     }
 
     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);
 
     UNTIMEOUT(ChapResponseTimeout, cstate);
 

+#ifdef CHAPMS
+    if ((cstate->resp_type == CHAP_MICROSOFT_V2) ||
+       (cstate->resp_type == CHAP_MICROSOFT)) {
+       long 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 = 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 - MS_CHAP_ERROR_BASE) {
+           case MS_CHAP_ERROR_RESTRICTED_LOGON_HOURS:
+               p = "Restricted logon hours";
+               break;
+
+           case MS_CHAP_ERROR_ACCT_DISABLED:
+               p = "Account disabled";
+               break;
+
+           case MS_CHAP_ERROR_PASSWD_EXPIRED:
+               p = "Password expired";
+               break;
+
+           case MS_CHAP_ERROR_NO_DIALIN_PERMISSION:
+               p = "No dialin permission";
+               break;
+
+           case MS_CHAP_ERROR_AUTHENTICATION_FAILURE:
+               p = "Authentication failure";
+               break;
+
+           case MS_CHAP_ERROR_CHANGING_PASSWORD:
+               /* Should never see this, we don't support Change Password. */
+               p = "Error changing password";
+               break;
+
+           default:
+               free(msg);
+               p = msg = malloc(len + 33);
+               if (!msg) {
+                   notice("Out of memory in ChapReceiveFailure");
+                   goto print_msg;
+               }
+               slprintf(p, len + 33, "Unknown authentication failure: %.*s",
+                        len, inp);
+               break;
+           }
+       }
+       len = strlen(p);
+    }
+#endif
+

     /*
      * Print message.
      */
     /*
      * 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);
 
     error("CHAP authentication failed");
     auth_withpeer_fail(cstate->unit, PPP_CHAP);

+#ifdef CHAPMS
+    if (msg) free(msg);
+#endif

 }
 
 
 }
 
 


@@ -748,6 +897,7 @@ ChapSendChallenge(cstate)
 
 /*
  * ChapSendStatus - Send a status response (ack or nak).
 
 /*
  * 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)
  */
 static void
 ChapSendStatus(cstate, code)


@@ -755,13 +905,63 @@ ChapSendStatus(cstate, code)
     int code;
 {
     u_char *outp;
     int code;
 {
     u_char *outp;

-    int outlen, msglen;
+    int i, outlen, msglen;

     char msg[256];
     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) {
+           /*
+            * 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
+            */
+           slprintf(p, q - p, "S=");
+           p += 2;
+           slprintf(p, q - p, "%s", cstate->saresponse);
+           p += strlen(cstate->saresponse);
+           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.
+            */
+           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.");
+    }

     msglen = strlen(msg);
 
     outlen = CHAP_HEADERLEN + msglen;
     msglen = strlen(msg);
 
     outlen = CHAP_HEADERLEN + msglen;


@@ -807,6 +1007,11 @@ ChapGenChallenge(cstate)
        /* MS-CHAP is fixed to an 8 octet challenge. */
        chal_len = 8;
        break;
        /* 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",
 #endif
     default:
        fatal("ChapGenChallenge: Unsupported challenge type %d",