r15484: Make accept_security_context() more compatible with how Samba3 (and

similarly built clients) behave.

This is better than just ignoring the checksum, if it isn't the GSSAPI
checksum.  (Samba4 clients in Samba3 mode use more than just the MD5
checksum, and will use a signed AES checksum if available.  Actual
samba3 may well do the same in future, against a suitable KDC).

Also a change for easier debugging of checksum issues.

Andrew Bartlett
(This used to be commit 120374f5f9e9af0653a26e0308e4bfdabbcaa3f3)

3 files changed, 46 insertions, 16 deletions

diff --git a/source4/heimdal/lib/gssapi/8003.c b/source4/heimdal/lib/gssapi/8003.c
index ad580811a5..73ecc90ea8 100644
--- a/source4/heimdal/lib/gssapi/8003.c
+++ b/source4/heimdal/lib/gssapi/8003.c
@@ -185,13 +185,9 @@ gssapi_krb5_verify_8003_checksum(
 	return GSS_S_BAD_BINDINGS;
     }
     
-    /* This is the case where Samba3 has built GSSAPI out of
-     * krb5 the 'dodgy' way.  We have to accept the non-GSSAPI
-     * checksum because windows does */
-    
     if(cksum->cksumtype != CKSUMTYPE_GSSAPI) {
-	    *flags = 0;
-	    return GSS_S_COMPLETE;
+	*minor_status = 0;
+	return GSS_S_BAD_BINDINGS;
     }
     
     /* XXX should handle checksums > 24 bytes */
diff --git a/source4/heimdal/lib/gssapi/accept_sec_context.c b/source4/heimdal/lib/gssapi/accept_sec_context.c
index 9ca60a6cdd..afca449c5c 100644
--- a/source4/heimdal/lib/gssapi/accept_sec_context.c
+++ b/source4/heimdal/lib/gssapi/accept_sec_context.c
@@ -371,15 +371,48 @@ gsskrb5_acceptor_start
 	    return ret;
 	}
 
-	ret = gssapi_krb5_verify_8003_checksum(minor_status,
-					       input_chan_bindings,
-					       authenticator->cksum,
-					       &flags,
-					       &(*context_handle)->fwd_data);
-	krb5_free_authenticator(gssapi_krb5_context, &authenticator);
-	if (ret) {
-	    return ret;
-	}
+        if (authenticator->cksum->cksumtype == CKSUMTYPE_GSSAPI) {
+            ret = gssapi_krb5_verify_8003_checksum(minor_status,
+                                                   input_chan_bindings,
+                                                   authenticator->cksum,
+                                                   &flags,
+                                                   &(*context_handle)->fwd_data);
+
+	    krb5_free_authenticator(gssapi_krb5_context, &authenticator);
+	    if (ret) {
+		return ret;
+	    }
+        } else {
+	    krb5_crypto crypto;
+
+	    kret = krb5_crypto_init(gssapi_krb5_context, 
+				   (*context_handle)->auth_context->keyblock, 
+				   0, &crypto);
+	    if(kret) {
+		krb5_free_authenticator(gssapi_krb5_context, &authenticator);
+
+		ret = GSS_S_FAILURE;
+		*minor_status = kret;
+		gssapi_krb5_set_error_string ();
+		return ret;
+	    }
+
+	    /* Windows accepts Samba3's use of a kerberos, 
+	       rather than GSSAPI checksum here */
+	    kret = krb5_verify_checksum(gssapi_krb5_context,
+					crypto, KRB5_KU_AP_REQ_AUTH_CKSUM, NULL, 0,
+					authenticator->cksum);
+	    krb5_free_authenticator(gssapi_krb5_context, &authenticator);
+
+	    if(kret) {
+		ret = GSS_S_FAILURE;
+		*minor_status = kret;
+		gssapi_krb5_set_error_string ();
+		return ret;
+	    }
+
+	    flags = GSS_C_MUTUAL_FLAG | GSS_C_REPLAY_FLAG | GSS_C_SEQUENCE_FLAG;
+        }
     }
     
     if(flags & GSS_C_MUTUAL_FLAG) {
diff --git a/source4/heimdal/lib/krb5/crypto.c b/source4/heimdal/lib/krb5/crypto.c
index 2e8160518b..1a37ec538b 100644
--- a/source4/heimdal/lib/krb5/crypto.c
+++ b/source4/heimdal/lib/krb5/crypto.c
@@ -2042,7 +2042,8 @@ verify_checksum(krb5_context context,
     }
     keyed_checksum = (ct->flags & F_KEYED) != 0;
     if(keyed_checksum && crypto == NULL) {
-	krb5_clear_error_string (context);
+	krb5_set_error_string (context, "checksum type %s is keyed, and requires a crypto context",
+			       ct->name);
 	return KRB5_PROG_SUMTYPE_NOSUPP; /* XXX */
     }
     if(keyed_checksum)