Fix decryption algorithm

Author: Sharcoux

apps/rn/src/tests/assets.js

@@ -3,7 +3,7 @@ import { encodeToBase64 } from 'pdf-lib';
 
 const PDF_PATH = `${RNFetchBlob.fs.dirs.DocumentDir}/out.pdf`;
 
-export const writePdf = async (pdfBytes, chunkSize = 100000): Promise<string> =>
+export const writePdf = async (pdfBytes, chunkSize = 100000) =>
   new Promise((resolve) => {
     const writes = [];
     RNFetchBlob.fs.writeStream(PDF_PATH, 'base64').then((stream) => {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@cantoo/pdf-lib",
-  "version": "1.19.0",
+  "version": "1.19.1",
   "description": "Create and modify PDF files with JavaScript",
   "author": "Andrew Dillon <andrew.dillon.j@gmail.com>",
   "contributors": [
@@ -33,7 +33,7 @@
     "François Billioud (https://github.com/Sharcoux)"
   ],
   "scripts": {
-    "release": "yarn build && yarn release:latest && git push origin master",
+    "release": "yarn build && yarn release:latest && git add . && git commit -m \"v$(yarn --silent get:version)\" && git push origin master",
     "release:latest": "yarn publish --tag latest && yarn pack",
     "release:next": "yarn publish --tag next",
     "release:prep": "yarn clean && yarn lint && yarn typecheck && yarn test && yarn build",
@@ -56,6 +56,7 @@
     "build:umd": "rollup --config rollup.config.js --file dist/pdf-lib.js --environment MODULE_TYPE:umd",
     "build:umd:min": "rollup --config rollup.config.js --file dist/pdf-lib.min.js --environment MINIFY,MODULE_TYPE:umd",
     "build:downlevel-dts": "rimraf ts3.4 && yarn downlevel-dts . ts3.4 && rimraf ts3.4/scratchpad",
+    "build:test": "yarn build:es && yarn build:umd",
     "scratchpad:start": "tsc --build scratchpad/tsconfig.json --watch",
     "scratchpad:run": "node scratchpad/build/scratchpad/index.js",
     "scratchpad:flame": "rimraf isolate*.log && node --prof scratchpad/build/scratchpad/index.js && node --prof-process --preprocess -j isolate*.log | flamebearer",
@@ -141,4 +142,4 @@
     "javascript",
     "library"
   ]
-}
+}

src/api/PDFDocument.ts

@@ -142,6 +142,7 @@ export default class PDFDocument {
     assertIs(ignoreEncryption, 'ignoreEncryption', ['boolean']);
     assertIs(parseSpeed, 'parseSpeed', ['number']);
     assertIs(throwOnInvalidObject, 'throwOnInvalidObject', ['boolean']);
+    assertIs(password, 'password', ['string', 'undefined']);
 
     const bytes = toUint8Array(pdf);
     const context = await PDFParser.forBytesWithOptions(
@@ -150,20 +151,21 @@ export default class PDFDocument {
       throwOnInvalidObject,
       capNumbers,
     ).parseDocument();
-    const pdfDoc = new PDFDocument(context, ignoreEncryption, updateMetadata, false);
-
-    if (pdfDoc.isEncrypted) {
+    if(!!context.lookup(context.trailerInfo.Encrypt)) {
       // Decrypt
-      const context = await PDFParser.forBytesWithOptions(
+      const fileIds = context.lookup(context.trailerInfo.ID, PDFArray)
+      const encryptDict = context.lookup(context.trailerInfo.Encrypt, PDFDict)
+      const decryptedContext = await PDFParser.forBytesWithOptions(
         bytes,
         parseSpeed,
         throwOnInvalidObject,
         capNumbers,
-        pdfDoc.cryptoFactory
+        new CipherTransformFactory(encryptDict, (fileIds.get(0) as PDFHexString).asBytes(), password)
       ).parseDocument();
-      return new PDFDocument(context, true, updateMetadata, true, password);
+      return new PDFDocument(decryptedContext, true, updateMetadata, true);
+    } else {
+      return new PDFDocument(context, ignoreEncryption, updateMetadata, false);
     }
-    return pdfDoc;
   }
 
   /**
@@ -191,8 +193,6 @@ export default class PDFDocument {
   /** Whether or not this document is encrypted. */
   readonly isEncrypted: boolean;
 
-  readonly cryptoFactory?: CipherTransformFactory;
-
   /** The default word breaks used in PDFPage.drawText */
   defaultWordBreaks: string[] = [' '];
 
@@ -212,7 +212,6 @@ export default class PDFDocument {
     ignoreEncryption: boolean,
     updateMetadata: boolean,
     isDecrypted: boolean,
-    password?: string
   ) {
     assertIs(context, 'context', [[PDFContext, 'PDFContext']]);
     assertIs(ignoreEncryption, 'ignoreEncryption', ['boolean']);
@@ -221,13 +220,9 @@ export default class PDFDocument {
     this.catalog = context.lookup(context.trailerInfo.Root) as PDFCatalog;
     this.isEncrypted = !!context.lookup(context.trailerInfo.Encrypt);
 
-    if (this.isEncrypted && !isDecrypted) {
-      const encryptDict = context.lookup(context.trailerInfo.Encrypt, PDFDict);
-      const fileIds = context.lookup(context.trailerInfo.ID, PDFArray);
-      this.cryptoFactory = new CipherTransformFactory(encryptDict, (fileIds.get(0) as PDFHexString).asBytes(), password)
-    } else if (this.isEncrypted) {
+    if (this.isEncrypted && isDecrypted) {
       // context.delete(context.trailerInfo.Encrypt);
-      delete context.trailerInfo.Encrypt;
+      // delete context.trailerInfo.Encrypt;
     }
 
     this.pageCache = Cache.populatedBy(this.computePages);

src/core/crypto.ts

@@ -1385,40 +1385,41 @@ class PDF20 {
   }
 }
 
+type Cipher = ARCFourCipher | NullCipher | AES128Cipher | AES256Cipher
 class CipherTransform {
-  private StringCipherConstructor: any;
-  private StreamCipherConstructor: any;
+  private StringCipherConstructor: () => Cipher;
+  private StreamCipherConstructor: () => Cipher;
 
-  constructor(stringCipherConstructor: any, streamCipherConstructor: any) {
+  constructor(stringCipherConstructor: () => Cipher, streamCipherConstructor: () => Cipher) {
     this.StringCipherConstructor = stringCipherConstructor;
     this.StreamCipherConstructor = streamCipherConstructor;
   }
 
   createStream(stream: StreamType, length: number) {
-    const cipher = new this.StreamCipherConstructor();
+    const cipher = this.StreamCipherConstructor();
     return new DecryptStream(
       stream,
       function cipherTransformDecryptStream(data, finalize) {
-        return cipher.decryptBlock(data, finalize);
+        return cipher.decryptBlock(data as Uint8Array, finalize);
       },
       length,
     );
   }
 
   decryptString(s: string) {
-    const cipher = new this.StringCipherConstructor();
+    const cipher = this.StringCipherConstructor();
     let data = stringAsByteArray(s);
     data = cipher.decryptBlock(data, true);
     return arrayAsString(data);
   }
 
   decryptBytes(d: Uint8Array) {
-    const cipher = new this.StringCipherConstructor();
+    const cipher = this.StringCipherConstructor();
     return cipher.decryptBlock(d, true);
   }
 
   encryptString(s: string) {
-    const cipher = new this.StringCipherConstructor();
+    const cipher = this.StringCipherConstructor();
     if (cipher instanceof AESBaseCipher) {
       // Append some chars equal to "16 - (M mod 16)"
       // where M is the string length (see section 7.6.2 in PDF specification)
@@ -1538,7 +1539,7 @@ class CipherTransformFactory {
     // meaningful when V is 4 or 5
     const encryptMetadata =
       (algorithm === 4 || algorithm === 5) &&
-      (dict.get(PDFName.of("EncryptMetadata")) as PDFBool).asBoolean() !== false;
+      (dict.get(PDFName.of("EncryptMetadata")) as PDFBool)?.asBoolean() !== false;
     this.encryptMetadata = encryptMetadata;
 
     let passwordBytes: Uint8Array | undefined;