get_in_tkt.c (krb5_get_in_tkt): If kdc_settime is enabled, then set

	the time_offset fields from the returned ticket's authtime value.

init_ctx.c (krb5_init_context): Initialize new fields in krb5_context
	(clockskew, kdc_req_sumtype, and kdc_default_options).

gc_via_tkt.c (krb5_get_cred_via_tkt): Perform the necessary
	sanity checking on the KDC response to make sure we detect tampering.

send_tgs.c (krb5_send_tgs): Set the expected nonce in the response
	structure.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@6653 dc483132-0cff-0310-8789-dd5450dbe970

6 files changed, 77 insertions, 55 deletions

diff --git a/src/lib/krb5/krb/ChangeLog b/src/lib/krb5/krb/ChangeLog
index 751962b1f..31ecd5d98 100644
--- a/src/lib/krb5/krb/ChangeLog
+++ b/src/lib/krb5/krb/ChangeLog
@@ -1,7 +1,23 @@
+Fri Sep  1 20:03:41 1995  Theodore Y. Ts'o  <tytso@dcl>
+
+	* get_in_tkt.c (krb5_get_in_tkt): If kdc_settime is enabled, then
+		set the time_offset fields from the returned ticket's
+		authtime value.
+
+	* init_ctx.c (krb5_init_context): Initialize new fields in
+		krb5_context (clockskew, kdc_req_sumtype, and
+		kdc_default_options).
+
+	* gc_via_tkt.c (krb5_get_cred_via_tkt): Perform the necessary
+		sanity checking on the KDC response to make sure we detect
+		tampering.
+
+	* send_tgs.c (krb5_send_tgs): Set the expected nonce in the
+		response structure.
 
 Fri Sep 1 11:16:43 EDT 1995	Paul Park	(pjpark@mit.edu)
-	* ser_ctx.c - Add handling of new time offset fields in the os_context.
 
+	* ser_ctx.c - Add handling of new time offset fields in the os_context.
 
 Tue Aug 29 14:14:26 EDT 1995	Paul Park	(pjpark@mit.edu)
 	* Makefile.in, .Sanitize, ser_{actx,adata,addr,auth,cksum,ctx,eblk,key,
diff --git a/src/lib/krb5/krb/gc_via_tkt.c b/src/lib/krb5/krb/gc_via_tkt.c
index c2f531f48..5dbbaed42 100644
--- a/src/lib/krb5/krb/gc_via_tkt.c
+++ b/src/lib/krb5/krb/gc_via_tkt.c
@@ -28,6 +28,9 @@
 #include "k5-int.h"
 #include "int-proto.h"
 
+extern krb5_deltat krb5_clockskew;
+#define in_clock_skew(date, now) (labs((date)-(now)) < krb5_clockskew)
+
 static krb5_error_code
 krb5_kdcrep2creds(context, pkdcrep, address, psectkt, ppcreds)
     krb5_context          context;
@@ -162,16 +165,7 @@ krb5_get_cred_via_tkt (context, tkt, kdcoptions, address, in_cred, out_cred)
 	if (retval) 			/* neither proper reply nor error! */
 	    goto error_4;
 
-#if 0
-	/* XXX need access to the actual assembled request...
-	   need a change to send_tgs */
-	if ((err_reply->ctime != request.ctime) ||
-	    !krb5_principal_compare(context,err_reply->server,request.server) ||
-	    !krb5_principal_compare(context, err_reply->client, request.client))
-	    retval = KRB5_KDCREP_MODIFIED;
-	else
-#endif
-	    retval = err_reply->error + ERROR_TABLE_BASE_krb5;
+	retval = err_reply->error + ERROR_TABLE_BASE_krb5;
 
 	krb5_free_error(context, err_reply);
 	goto error_4;
@@ -187,42 +181,36 @@ krb5_get_cred_via_tkt (context, tkt, kdcoptions, address, in_cred, out_cred)
 	goto error_3;
     }
     
-    /* now it's decrypted and ready for prime time */
-    if (!krb5_principal_compare(context, dec_rep->client, tkt->client)) {
+    /* make sure the response hasn't been tampered with..... */
+    if (!krb5_principal_compare(context, dec_rep->client, tkt->client) ||
+	!krb5_principal_compare(context, dec_rep->enc_part2->server,
+				in_cred->server) ||
+	!krb5_principal_compare(context, dec_rep->ticket->server,
+				in_cred->server) ||
+	(dec_rep->enc_part2->nonce != tgsrep.expected_nonce) ||
+	((in_cred->times.starttime != 0) &&
+	 (in_cred->times.starttime != dec_rep->enc_part2->times.starttime)) ||
+	((in_cred->times.endtime != 0) &&
+	 (dec_rep->enc_part2->times.endtime > in_cred->times.endtime)) ||
+	((kdcoptions & KDC_OPT_RENEWABLE) &&
+	 (in_cred->times.renew_till != 0) &&
+	 (dec_rep->enc_part2->times.renew_till > in_cred->times.renew_till)) ||
+	((kdcoptions & KDC_OPT_RENEWABLE_OK) &&
+	 (dec_rep->enc_part2->flags & KDC_OPT_RENEWABLE) &&
+	 (in_cred->times.endtime != 0) &&
+	 (dec_rep->enc_part2->times.renew_till > in_cred->times.endtime))
+	) {
 	retval = KRB5_KDCREP_MODIFIED;
 	goto error_3;
     }
 
-#if 0
-    /* XXX probably need access to the request */
-    /* check the contents for sanity: */
-    if (!krb5_principal_compare(context, dec_rep->client, request.client)
-	|| !krb5_principal_compare(context, dec_rep->enc_part2->server, request.server)
-	|| !krb5_principal_compare(context, dec_rep->ticket->server, request.server)
-	|| (request.nonce != dec_rep->enc_part2->nonce)
-	/* XXX check for extraneous flags */
-	/* XXX || (!krb5_addresses_compare(context, addrs, dec_rep->enc_part2->caddrs)) */
-	|| ((request.from != 0) &&
-	    (request.from != dec_rep->enc_part2->times.starttime))
-	|| ((request.till != 0) &&
-	    (dec_rep->enc_part2->times.endtime > request.till))
-	|| ((request.kdc_options & KDC_OPT_RENEWABLE) &&
-	    (request.rtime != 0) &&
-	    (dec_rep->enc_part2->times.renew_till > request.rtime))
-	|| ((request.kdc_options & KDC_OPT_RENEWABLE_OK) &&
-	    (dec_rep->enc_part2->flags & KDC_OPT_RENEWABLE) &&
-	    (request.till != 0) &&
-	    (dec_rep->enc_part2->times.renew_till > request.till))
-	)
-	retval = KRB5_KDCREP_MODIFIED;
-
-    if (!request.from && !in_clock_skew(dec_rep->enc_part2->times.starttime)) {
+    if (!in_cred->times.starttime &&
+	!in_clock_skew(dec_rep->enc_part2->times.starttime,
+		       tgsrep.request_time)) {
 	retval = KRB5_KDCREP_SKEW;
 	goto error_3;
     }
     
-#endif
-
     retval = krb5_kdcrep2creds(context, dec_rep, address, 
 			       &in_cred->second_ticket,  out_cred);
 
diff --git a/src/lib/krb5/krb/get_in_tkt.c b/src/lib/krb5/krb/get_in_tkt.c
index f6e5c3248..78be610b0 100644
--- a/src/lib/krb5/krb/get_in_tkt.c
+++ b/src/lib/krb5/krb/get_in_tkt.c
@@ -97,6 +97,7 @@ krb5_get_in_tkt(context, options, addrs, etypes, ptypes, key_proc, keyseed,
     krb5_keyblock *decrypt_key = 0;
     krb5_timestamp time_now;
 /*    krb5_pa_data	*padata; */
+    krb5_pa_data  **preauth_to_use = 0;
     int f_salt = 0, use_salt = 0;
     krb5_data salt;
     char k4_version;		/* same type as *(krb5_data::data) */
@@ -158,11 +159,6 @@ krb5_get_in_tkt(context, options, addrs, etypes, ptypes, key_proc, keyseed,
     request.from = creds->times.starttime;
     request.till = creds->times.endtime;
     request.rtime = creds->times.renew_till;
-    if ((retval = krb5_timeofday(context, &time_now)))
-	goto cleanup;
-
-    /* XXX we know they are the same size... */
-    request.nonce = (krb5_int32) time_now;
 
     if (etypes) 
 	request.etype = etypes;
@@ -174,6 +170,12 @@ krb5_get_in_tkt(context, options, addrs, etypes, ptypes, key_proc, keyseed,
     request.unenc_authdata = 0;
     request.second_ticket = 0;
 
+    if ((retval = krb5_timeofday(context, &time_now)))
+	goto cleanup;
+
+    /* XXX we know they are the same size... */
+    request.nonce = (krb5_int32) time_now;
+
     /* encode & send to KDC */
     retval = encode_krb5_as_req(&request, &packet);
     if (!etypes)
@@ -195,14 +197,15 @@ krb5_get_in_tkt(context, options, addrs, etypes, ptypes, key_proc, keyseed,
 	    /* some other error code--??? */	    
 	    goto cleanup;
     
-	/* it was an error */
+	if (err_reply->error == KDC_ERR_PREAUTH_REQUIRED &&
+	    err_reply->e_data.length > 0) {
+	    retval = decode_krb5_padata_sequence(&err_reply->e_data,
+						 &preauth_to_use);
+    	    /* XXX we need to actually do something with the info */
+	    krb5_free_pa_data(context, preauth_to_use);
+	}
 
-	if ((err_reply->ctime != request.nonce) ||
-	    !krb5_principal_compare(context, err_reply->server, request.server) ||
-	    !krb5_principal_compare(context, err_reply->client, request.client))
-	    retval = KRB5_KDCREP_MODIFIED;
-	else
-	    retval = err_reply->error + ERROR_TABLE_BASE_krb5;
+	retval = err_reply->error + ERROR_TABLE_BASE_krb5;
 
 	/* XXX somehow make error msg text available to application? */
 
@@ -310,7 +313,11 @@ krb5_get_in_tkt(context, options, addrs, etypes, ptypes, key_proc, keyseed,
 	retval = KRB5_KDCREP_SKEW;
 	goto cleanup;
     }
-    
+ 
+   if (context->library_options & KRB5_LIBOPT_SYNC_KDCTIME)
+       krb5_set_time_offsets(context,
+			     as_reply->enc_part2->times.authtime - time_now,
+			     0);
 
     /* XXX issue warning if as_reply->enc_part2->key_exp is nearby */
 	
diff --git a/src/lib/krb5/krb/init_ctx.c b/src/lib/krb5/krb/init_ctx.c
index 00bf2d528..077cfdd34 100644
--- a/src/lib/krb5/krb/init_ctx.c
+++ b/src/lib/krb5/krb/init_ctx.c
@@ -31,6 +31,7 @@ krb5_init_context(context)
 {
 	krb5_context ctx;
 	krb5_error_code retval;
+	int tmp;
 
 	*context = 0;
 
@@ -46,9 +47,18 @@ krb5_init_context(context)
 
 	if ((retval = krb5_os_init_context(ctx)))
 		goto cleanup;
-	
 
 	ctx->default_realm = 0;
+	profile_get_integer(ctx->profile, "libdefaults",
+			    "clockskew", 0, 5 * 60,
+			    &tmp);
+	ctx->clockskew = tmp;
+	ctx->kdc_req_sumtype = CKSUMTYPE_RSA_MD5;
+	ctx->kdc_default_options = KDC_OPT_RENEWABLE_OK;
+	profile_get_integer(ctx->profile, "libdefaults",
+			    "kdc_timesync", 0, 0,
+			    &tmp);
+	ctx->library_options = tmp ? KRB5_LIBOPT_SYNC_KDCTIME : 0;
 
 	*context = ctx;
 	return 0;
diff --git a/src/lib/krb5/krb/krbconfig.c b/src/lib/krb5/krb/krbconfig.c
index f0ae06d5c..7401bd38f 100644
--- a/src/lib/krb5/krb/krbconfig.c
+++ b/src/lib/krb5/krb/krbconfig.c
@@ -27,5 +27,5 @@
 #include "k5-int.h"
 
 krb5_deltat krb5_clockskew = 5 * 60;	/* five minutes */
-krb5_cksumtype krb5_kdc_req_sumtype = CKSUMTYPE_RSA_MD4;
+krb5_cksumtype krb5_kdc_req_sumtype = CKSUMTYPE_RSA_MD5;
 krb5_flags krb5_kdc_default_options = KDC_OPT_RENEWABLE_OK;
diff --git a/src/lib/krb5/krb/send_tgs.c b/src/lib/krb5/krb/send_tgs.c
index 64331d8d6..cad41582a 100644
--- a/src/lib/krb5/krb/send_tgs.c
+++ b/src/lib/krb5/krb/send_tgs.c
@@ -206,7 +206,8 @@ krb5_send_tgs(context, kdcoptions, timestruct, etypes, sname, addrs,
     if ((retval = krb5_timeofday(context, &time_now)))
 	return(retval);
     /* XXX we know they are the same size... */
-    tgsreq.nonce = (krb5_int32) time_now;
+    rep->expected_nonce = tgsreq.nonce = (krb5_int32) time_now;
+    rep->request_time = time_now;
 
     tgsreq.addresses = (krb5_address **) addrs;