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Basic DecryptStream functionality; md5 and arcfour algorithms

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notmasteryet 2011-06-24 07:51:31 -05:00
parent 375c4bf529
commit c78c209eb5
3 changed files with 319 additions and 33 deletions
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90
pdf.js
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@ -56,6 +56,14 @@ function bytesToString(bytes) {
return str;
}
function stringToBytes(str) {
var length = str.length;
var bytes = new Uint8Array(length);
for (var n = 0; n < length; ++n)
bytes[n] = str.charCodeAt(n) & 0xFF;
return bytes;
}
var Stream = (function() {
function constructor(arrayBuffer, start, length, dict) {
this.bytes = Uint8Array(arrayBuffer);
@ -741,11 +749,34 @@ var PredictorStream = (function() {
})();
var DecryptStream = (function() {
function constructor(str, fileKey, encAlgorithm, keyLength) {
TODO("decrypt stream is not implemented");
function constructor(str, decrypt) {
this.str = str;
this.dict = str.dict;
this.decrypt = decrypt;
DecodeStream.call(this);
}
constructor.prototype = Stream.prototype;
const chunkSize = 512;
constructor.prototype = Object.create(DecodeStream.prototype);
constructor.prototype.readBlock = function() {
var chunk = this.str.getBytes(chunkSize);
if (!chunk || chunk.length == 0) {
this.eof = true;
return;
}
var decrypt = this.decrypt;
chunk = decrypt(chunk);
var bufferLength = this.bufferLength;
var i, n = chunk.length;
var buffer = this.ensureBuffer(bufferLength + n);
for (i = 0; i < n; i++)
buffer[bufferLength++] = chunk[i];
this.bufferLength = n;
this.eof = n < chunkSize;
};
return constructor;
})();
@ -919,10 +950,10 @@ var Lexer = (function() {
function ToHexDigit(ch) {
if (ch >= "0" && ch <= "9")
return ch - "0";
ch = ch.toLowerCase();
if (ch >= "a" && ch <= "f")
return ch - "a";
return ch.charCodeAt(0) - 48;
ch = ch.toUpperCase();
if (ch >= "A" && ch <= "F")
return ch.charCodeAt(0) - 55;
return -1;
}
@ -1216,7 +1247,7 @@ var Parser = (function() {
// don't buffer inline image data
this.buf2 = (this.inlineImg > 0) ? null : this.lexer.getObj();
},
getObj: function() {
getObj: function(cipherTransform) {
// refill buffer after inline image data
if (this.inlineImg == 2)
this.refill();
@ -1242,7 +1273,7 @@ var Parser = (function() {
this.shift();
if (IsEOF(this.buf1))
break;
dict.set(key, this.getObj());
dict.set(key, this.getObj(cipherTransform));
}
}
if (IsEOF(this.buf1))
@ -1251,7 +1282,7 @@ var Parser = (function() {
// stream objects are not allowed inside content streams or
// object streams
if (this.allowStreams && IsCmd(this.buf2, "stream")) {
return this.makeStream(dict);
return this.makeStream(dict, cipherTransform);
} else {
this.shift();
}
@ -1270,17 +1301,8 @@ var Parser = (function() {
} else if (IsString(this.buf1)) { // string
var str = this.buf1;
this.shift();
if (this.fileKey) {
var decrypt = new DecryptStream(new StringStream(str),
this.fileKey,
this.encAlgorithm,
this.keyLength);
var str = "";
var pos = decrypt.pos;
var length = decrypt.length;
while (pos++ > length)
str += decrypt.getChar();
}
if (cipherTransform)
str = cipherTransform.decryptString(str);
return str;
}
@ -1289,7 +1311,7 @@ var Parser = (function() {
this.shift();
return obj;
},
makeStream: function(dict) {
makeStream: function(dict, cipherTransform) {
var lexer = this.lexer;
var stream = lexer.stream;
@ -1316,12 +1338,8 @@ var Parser = (function() {
this.shift();
stream = stream.makeSubStream(pos, length, dict);
if (this.fileKey) {
stream = new DecryptStream(stream,
this.fileKey,
this.encAlgorithm,
this.keyLength);
}
if (cipherTransform)
stream = cipherTransform.createString(stream);
stream = this.filter(stream, dict, length);
stream.parameters = dict;
return stream;
@ -1450,12 +1468,18 @@ var XRef = (function() {
this.xrefstms = {};
var trailerDict = this.readXRef(startXRef);
// prepare the XRef cache
this.cache = [];
var encrypt = trailerDict.get("Encrypt");
if (encrypt) {
var fileId = trailerDict.get("ID");
this.encrypt = new CipherTransformFactory(this.fetch(encrypt), fileId[0] /*, password */);
}
// get the root dictionary (catalog) object
if (!IsRef(this.root = trailerDict.get("Root")))
error("Invalid root reference");
// prepare the XRef cache
this.cache = [];
}
constructor.prototype = {
@ -1643,7 +1667,7 @@ var XRef = (function() {
}
error("bad XRef entry");
}
e = parser.getObj();
e = parser.getObj(this.encrypt);
// Don't cache streams since they are mutable.
if (!IsStream(e))
this.cache[num] = e;
@ -2462,7 +2486,7 @@ var CanvasGraphics = (function() {
}
}
} else if (cmd == "Tf") { // eagerly collect all fonts
var fontRes = resources.get("Font");
var fontRes; // = resources.get("Font");
if (fontRes) {
fontRes = xref.fetchIfRef(fontRes);
var font = xref.fetchIfRef(fontRes.get(args[0].name));