110 lines
3.1 KiB
ActionScript
110 lines
3.1 KiB
ActionScript
package com.hurlant.util.der
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{
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import com.hurlant.math.BigInteger;
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import flash.utils.ByteArray;
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import com.hurlant.util.der.Sequence;
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// goal 1: to be able to parse an RSA Private Key PEM file.
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// goal 2: to parse an X509v3 cert. kinda.
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/**
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* DER for dummies:
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* http://luca.ntop.org/Teaching/Appunti/asn1.html
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*
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* This class does the bare minimum to get by. if that.
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*/
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public class DER
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{
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public static var indent:String = "";
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public static function parse(der:ByteArray, structure:*=null):IAsn1Type {
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// type
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var type:int = der.readUnsignedByte();
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var constructed:Boolean = (type&0x20)!=0;
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type &=0x1F;
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// length
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var len:int = der.readUnsignedByte();
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if (len>=0x80) {
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// long form of length
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var count:int = len & 0x7f;
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len = 0;
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while (count>0) {
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len = (len<<8) | der.readUnsignedByte();
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count--;
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}
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}
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// data
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var b:ByteArray
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switch (type) {
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case 0x00: // WHAT IS THIS THINGY? (seen as 0xa0)
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// (note to self: read a spec someday.)
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// for now, treat as a sequence.
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case 0x10: // SEQUENCE/SEQUENCE OF. whatever
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// treat as an array
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var p:int = der.position;
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var o:Sequence = new Sequence(type, len);
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var arrayStruct:Array = structure as Array;
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while (der.position < p+len) {
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var tmpStruct:Object = null
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if (arrayStruct!=null) {
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tmpStruct = arrayStruct.shift();
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}
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if (tmpStruct!=null) {
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var name:String = tmpStruct.name;
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var value:* = tmpStruct.value;
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var obj:IAsn1Type = DER.parse(der, value);
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o.push(obj);
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o[name] = obj;
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} else {
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o.push(DER.parse(der));
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}
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}
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return o;
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case 0x11: // SET/SET OF
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p = der.position;
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var s:Set = new Set(type, len);
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while (der.position < p+len) {
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s.push(DER.parse(der));
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}
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return s;
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case 0x02: // INTEGER
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// put in a BigInteger
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b = new ByteArray;
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der.readBytes(b,0,len);
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b.position=0;
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return new Integer(type, len, b);
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case 0x06: // OBJECT IDENTIFIER:
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b = new ByteArray;
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der.readBytes(b,0,len);
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b.position=0;
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return new ObjectIdentifier(type, len, b);
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default:
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trace("I DONT KNOW HOW TO HANDLE DER stuff of TYPE "+type);
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// fall through
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case 0x04: // OCTET STRING
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case 0x03: // BIT STRING
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// stuff in a ByteArray for now.
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var bs:ByteString = new ByteString(type, len);
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der.readBytes(bs,0,len);
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return bs;
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case 0x05: // NULL
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// if len!=0, something's horribly wrong.
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// should I check?
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return null;
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case 0x13: // PrintableString
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var ps:PrintableString = new PrintableString(type, len);
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ps.setString(der.readMultiByte(len, "US-ASCII"));
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return ps;
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case 0x14: // T61String
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ps = new PrintableString(type, len);
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ps.setString(der.readMultiByte(len, "latin1"));
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return ps;
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case 0x17: // UTCTime
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var ut:UTCTime = new UTCTime(type, len);
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ut.setUTCTime(der.readMultiByte(len, "US-ASCII"));
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return ut;
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}
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}
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}
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} |