--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nss/lib/certdb/xbsconst.c	Mon Jul 28 10:47:06 2014 +0200
@@ -0,0 +1,145 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * X.509 v3 Basic Constraints Extension 
+ */
+
+#include "prtypes.h"
+#include <limits.h>     /* for LONG_MAX */
+#include "seccomon.h"
+#include "secdert.h"
+#include "secoidt.h"
+#include "secasn1t.h"
+#include "secasn1.h"
+#include "certt.h"
+#include "secder.h"
+#include "prprf.h"
+#include "secerr.h"
+
+typedef struct EncodedContext{
+    SECItem isCA;
+    SECItem pathLenConstraint;
+    SECItem encodedValue;
+    PLArenaPool *arena;
+}EncodedContext;
+
+static const SEC_ASN1Template CERTBasicConstraintsTemplate[] = {
+    { SEC_ASN1_SEQUENCE,
+	  0, NULL, sizeof(EncodedContext) },
+    { SEC_ASN1_OPTIONAL | SEC_ASN1_BOOLEAN,		/* XXX DER_DEFAULT */
+	  offsetof(EncodedContext,isCA)},
+    { SEC_ASN1_OPTIONAL | SEC_ASN1_INTEGER,
+	  offsetof(EncodedContext,pathLenConstraint) },
+    { 0, }
+};
+
+static unsigned char hexTrue = 0xff;
+static unsigned char hexFalse = 0x00;
+
+#define GEN_BREAK(status) rv = status; break;
+
+SECStatus CERT_EncodeBasicConstraintValue
+   (PLArenaPool *arena, CERTBasicConstraints *value, SECItem *encodedValue)
+{
+    EncodedContext encodeContext;
+    PLArenaPool *our_pool = NULL;
+    SECStatus rv = SECSuccess;
+
+    do {
+	PORT_Memset (&encodeContext, 0, sizeof (encodeContext));
+	if (!value->isCA && value->pathLenConstraint >= 0) {
+	    PORT_SetError (SEC_ERROR_EXTENSION_VALUE_INVALID);
+	    GEN_BREAK (SECFailure);
+	}
+
+        encodeContext.arena = arena;
+	if (value->isCA == PR_TRUE) {
+	    encodeContext.isCA.data =  &hexTrue ;
+	    encodeContext.isCA.len = 1;
+	}
+
+	/* If the pathLenConstraint is less than 0, then it should be
+	 * omitted from the encoding.
+	 */
+	if (value->isCA && value->pathLenConstraint >= 0) {
+	    our_pool = PORT_NewArena (SEC_ASN1_DEFAULT_ARENA_SIZE);
+	    if (our_pool == NULL) {
+		PORT_SetError (SEC_ERROR_NO_MEMORY);
+		GEN_BREAK (SECFailure);
+	    }
+	    if (SEC_ASN1EncodeUnsignedInteger
+		(our_pool, &encodeContext.pathLenConstraint,
+		 (unsigned long)value->pathLenConstraint) == NULL) {
+		PORT_SetError (SEC_ERROR_NO_MEMORY);
+		GEN_BREAK (SECFailure);
+	    }
+	}
+	if (SEC_ASN1EncodeItem (arena, encodedValue, &encodeContext,
+				CERTBasicConstraintsTemplate) == NULL) {
+	    GEN_BREAK (SECFailure);
+	}
+    } while (0);
+    if (our_pool)
+	PORT_FreeArena (our_pool, PR_FALSE);
+    return(rv);
+
+}
+
+SECStatus CERT_DecodeBasicConstraintValue
+   (CERTBasicConstraints *value, const SECItem *encodedValue)
+{
+    EncodedContext decodeContext;
+    PLArenaPool *our_pool;
+    SECStatus rv = SECSuccess;
+
+    do {
+	PORT_Memset (&decodeContext, 0, sizeof (decodeContext));
+	/* initialize the value just in case we got "0x30 00", or when the
+	   pathLenConstraint is omitted.
+         */
+	decodeContext.isCA.data =&hexFalse;
+	decodeContext.isCA.len = 1;
+	
+	our_pool = PORT_NewArena (SEC_ASN1_DEFAULT_ARENA_SIZE);
+	if (our_pool == NULL) {
+	    PORT_SetError (SEC_ERROR_NO_MEMORY);
+	    GEN_BREAK (SECFailure);
+	}
+
+        rv = SEC_QuickDERDecodeItem
+	     (our_pool, &decodeContext, CERTBasicConstraintsTemplate, encodedValue);
+	if (rv == SECFailure)
+	    break;
+	
+	value->isCA = decodeContext.isCA.data 
+	              ? (PRBool)(decodeContext.isCA.data[0] != 0)
+		      : PR_FALSE;
+	if (decodeContext.pathLenConstraint.data == NULL) {
+	    /* if the pathLenConstraint is not encoded, and the current setting
+	      is CA, then the pathLenConstraint should be set to a negative number
+	      for unlimited certificate path.
+	     */
+	    if (value->isCA)
+		value->pathLenConstraint = CERT_UNLIMITED_PATH_CONSTRAINT;
+	} else if (value->isCA) {
+	    long len = DER_GetInteger (&decodeContext.pathLenConstraint);
+	    if (len < 0 || len == LONG_MAX) {
+		PORT_SetError (SEC_ERROR_BAD_DER);
+		GEN_BREAK (SECFailure);
+	    }
+	    value->pathLenConstraint = len;
+	} else {
+	    /* here we get an error where the subject is not a CA, but
+	       the pathLenConstraint is set */
+	    PORT_SetError (SEC_ERROR_BAD_DER);
+	    GEN_BREAK (SECFailure);
+	    break;
+	}
+	 
+    } while (0);
+    PORT_FreeArena (our_pool, PR_FALSE);
+    return (rv);
+
+}