mirrors/pdf.js
1
0
Fork 0
mirror of https://github.com/mozilla/pdf.js.git synced 2025-04-26 10:08:06 +02:00
Code Activity

Fixes user and owner passwords logic

Browse source
This commit is contained in:
Yury Delendik 2012-05-12 21:34:32 -05:00
parent 52832894f5
commit 910ba0b91f
2 changed files with 130 additions and 17 deletions
Download patch file Download diff file Expand all files Collapse all files

84
src/crypto.js
View file

@ -419,13 +419,14 @@ var CipherTransform = (function CipherTransformClosure() {
})();
var CipherTransformFactory = (function CipherTransformFactoryClosure() {
var defaultPasswordBytes = new Uint8Array([
0x28, 0xBF, 0x4E, 0x5E, 0x4E, 0x75, 0x8A, 0x41,
0x64, 0x00, 0x4E, 0x56, 0xFF, 0xFA, 0x01, 0x08,
0x2E, 0x2E, 0x00, 0xB6, 0xD0, 0x68, 0x3E, 0x80,
0x2F, 0x0C, 0xA9, 0xFE, 0x64, 0x53, 0x69, 0x7A]);
function prepareKeyData(fileId, password, ownerPassword, userPassword,
flags, revision, keyLength, encryptMetadata) {
var defaultPasswordBytes = new Uint8Array([
0x28, 0xBF, 0x4E, 0x5E, 0x4E, 0x75, 0x8A, 0x41,
0x64, 0x00, 0x4E, 0x56, 0xFF, 0xFA, 0x01, 0x08,
0x2E, 0x2E, 0x00, 0xB6, 0xD0, 0x68, 0x3E, 0x80,
0x2F, 0x0C, 0xA9, 0xFE, 0x64, 0x53, 0x69, 0x7A]);
var hashData = new Uint8Array(100), i = 0, j, n;
if (password) {
n = Math.min(32, password.length);
@ -462,9 +463,8 @@ var CipherTransformFactory = (function CipherTransformFactoryClosure() {
var cipher, checkData;
if (revision >= 3) {
// padded password in hashData, we can use this array for user
// password check
i = 32;
for (i = 0; i < 32; ++i)
hashData[i] = defaultPasswordBytes[i];
for (j = 0, n = fileId.length; j < n; ++j)
hashData[i++] = fileId[j];
cipher = new ARCFourCipher(encryptionKey);
@ -477,16 +477,53 @@ var CipherTransformFactory = (function CipherTransformFactoryClosure() {
cipher = new ARCFourCipher(derivedKey);
checkData = cipher.encryptBlock(checkData);
}
for (j = 0, n = checkData.length; j < n; ++j) {
if (userPassword[j] != checkData[j])
return null;
}
} else {
cipher = new ARCFourCipher(encryptionKey);
checkData = cipher.encryptBlock(hashData.subarray(0, 32));
}
for (j = 0, n = checkData.length; j < n; ++j) {
if (userPassword[j] != checkData[j])
error('incorrect password');
checkData = cipher.encryptBlock(defaultPasswordBytes);
for (j = 0, n = checkData.length; j < n; ++j) {
if (userPassword[j] != checkData[j])
return null;
}
}
return encryptionKey;
}
function decodeUserPassword(password, ownerPassword, revision, keyLength) {
var hashData = new Uint8Array(32), i = 0, j, n;
n = Math.min(32, password.length);
for (; i < n; ++i)
hashData[i] = password[i];
j = 0;
while (i < 32) {
hashData[i++] = defaultPasswordBytes[j++];
}
var hash = calculateMD5(hashData, 0, i);
var keyLengthInBytes = keyLength >> 3;
if (revision >= 3) {
for (j = 0; j < 50; ++j) {
hash = calculateMD5(hash, 0, hash.length);
}
}
var cipher, userPassword;
if (revision >= 3) {
userPassword = ownerPassword;
var derivedKey = new Uint8Array(keyLengthInBytes), k;
for (j = 19; j >= 0; j--) {
for (k = 0; k < keyLengthInBytes; ++k)
derivedKey[k] = hash[k] ^ j;
cipher = new ARCFourCipher(derivedKey);
userPassword = cipher.encryptBlock(userPassword);
}
} else {
cipher = new ARCFourCipher(hash.subarray(0, keyLengthInBytes));
userPassword = cipher.encryptBlock(ownerPassword);
}
return userPassword;
}
var identityName = new Name('Identity');
@ -516,10 +553,23 @@ var CipherTransformFactory = (function CipherTransformFactoryClosure() {
if (password)
passwordBytes = stringToBytes(password);
this.encryptionKey = prepareKeyData(fileIdBytes, passwordBytes,
ownerPassword, userPassword,
flags, revision,
keyLength, encryptMetadata);
var encryptionKey = prepareKeyData(fileIdBytes, passwordBytes,
ownerPassword, userPassword, flags,
revision, keyLength, encryptMetadata);
if (!encryptionKey && password) {
// Attempting use the password as an owner password
var decodedPassword = decodeUserPassword(passwordBytes, ownerPassword,
revision, keyLength);
encryptionKey = prepareKeyData(fileIdBytes, decodedPassword,
ownerPassword, userPassword, flags,
revision, keyLength, encryptMetadata);
}
if (!encryptionKey)
error('incorrect password or encryption data');
this.encryptionKey = encryptionKey;
if (algorithm == 4) {
this.cf = dict.get('CF');
this.stmf = dict.get('StmF') || identityName;