[CIFS] add OIDs for KRB5 and MSKRB5 to ASN1 parsing routines

Also, fix the parser to recognize them and set the secType
accordingly. Make CIFSSMBNegotiate not error out automatically
after parsing the securityBlob.

Also thanks to Q (Igor) and Simo for their help on this
set of kerberos patches (and Dave Howells for help on the
upcall).

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/asn1.c b/fs/cifs/asn1.c
index 2a01f3e..bcda2c6 100644
--- a/fs/cifs/asn1.c
+++ b/fs/cifs/asn1.c
@@ -77,8 +77,12 @@
 
 #define SPNEGO_OID_LEN 7
 #define NTLMSSP_OID_LEN  10
+#define KRB5_OID_LEN  7
+#define MSKRB5_OID_LEN  7
 static unsigned long SPNEGO_OID[7] = { 1, 3, 6, 1, 5, 5, 2 };
 static unsigned long NTLMSSP_OID[10] = { 1, 3, 6, 1, 4, 1, 311, 2, 2, 10 };
+static unsigned long KRB5_OID[7] = { 1, 2, 840, 113554, 1, 2, 2 };
+static unsigned long MSKRB5_OID[7] = { 1, 2, 840, 48018, 1, 2, 2 };
 
 /*
  * ASN.1 context.
@@ -457,6 +461,7 @@
 	unsigned long *oid = NULL;
 	unsigned int cls, con, tag, oidlen, rc;
 	int use_ntlmssp = FALSE;
+	int use_kerberos = FALSE;
 
 	*secType = NTLM; /* BB eventually make Kerberos or NLTMSSP the default*/
 
@@ -545,18 +550,28 @@
 				return 0;
 			}
 			if ((tag == ASN1_OJI) && (con == ASN1_PRI)) {
-				rc = asn1_oid_decode(&ctx, end, &oid, &oidlen);
-				if (rc) {
+				if (asn1_oid_decode(&ctx, end, &oid, &oidlen)) {
+
 					cFYI(1,
 					  ("OID len = %d oid = 0x%lx 0x%lx "
 					   "0x%lx 0x%lx",
 					   oidlen, *oid, *(oid + 1),
 					   *(oid + 2), *(oid + 3)));
-					rc = compare_oid(oid, oidlen,
-						 NTLMSSP_OID, NTLMSSP_OID_LEN);
-					kfree(oid);
-					if (rc)
+
+					if (compare_oid(oid, oidlen,
+							MSKRB5_OID,
+							MSKRB5_OID_LEN))
+						use_kerberos = TRUE;
+					else if (compare_oid(oid, oidlen,
+							     KRB5_OID,
+							     KRB5_OID_LEN))
+						use_kerberos = TRUE;
+					else if (compare_oid(oid, oidlen,
+							     NTLMSSP_OID,
+							     NTLMSSP_OID_LEN))
 						use_ntlmssp = TRUE;
+
+					kfree(oid);
 				}
 			} else {
 				cFYI(1, ("Should be an oid what is going on?"));
@@ -609,12 +624,10 @@
 			 ctx.pointer));	/* is this UTF-8 or ASCII? */
 	}
 
-	/* if (use_kerberos)
-	   *secType = Kerberos
-	   else */
-	if (use_ntlmssp) {
+	if (use_kerberos)
+		*secType = Kerberos;
+	else if (use_ntlmssp)
 		*secType = NTLMSSP;
-	}
 
 	return 1;
 }