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Introduce a common base class for the PDF17 and PDF20 crypto classes

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With the exception of a different hashing function these classes are identical, and the base class thus help reduce code duplication.

This patch reduces the size of the `gulp mozcentral` build with 1344 bytes, which isn't a lot but still cannot hurt.
This commit is contained in:
Jonas Jenwald 2025-03-12 12:21:47 +01:00
parent d74619847d
commit 2ff6829e47
1 changed files with 26 additions and 44 deletions
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70
src/core/crypto.js
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@ -632,13 +632,26 @@ class AES256Cipher extends AESBaseCipher {
} }
} }
class PDF17 { class PDFBase {
constructor() {
if (
(typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) &&
this.constructor === PDFBase
) {
unreachable("Cannot initialize PDFBase.");
}
}
_hash(password, input, userBytes) {
unreachable("Abstract method `_hash` called");
}
checkOwnerPassword(password, ownerValidationSalt, userBytes, ownerPassword) { checkOwnerPassword(password, ownerValidationSalt, userBytes, ownerPassword) {
const hashData = new Uint8Array(password.length + 56); const hashData = new Uint8Array(password.length + 56);
hashData.set(password, 0); hashData.set(password, 0);
hashData.set(ownerValidationSalt, password.length); hashData.set(ownerValidationSalt, password.length);
hashData.set(userBytes, password.length + ownerValidationSalt.length); hashData.set(userBytes, password.length + ownerValidationSalt.length);
const result = calculateSHA256(hashData, 0, hashData.length); const result = this._hash(password, hashData, userBytes);
return isArrayEqual(result, ownerPassword); return isArrayEqual(result, ownerPassword);
} }
@ -646,7 +659,7 @@ class PDF17 {
const hashData = new Uint8Array(password.length + 8); const hashData = new Uint8Array(password.length + 8);
hashData.set(password, 0); hashData.set(password, 0);
hashData.set(userValidationSalt, password.length); hashData.set(userValidationSalt, password.length);
const result = calculateSHA256(hashData, 0, hashData.length); const result = this._hash(password, hashData, []);
return isArrayEqual(result, userPassword); return isArrayEqual(result, userPassword);
} }
@ -655,7 +668,7 @@ class PDF17 {
hashData.set(password, 0); hashData.set(password, 0);
hashData.set(ownerKeySalt, password.length); hashData.set(ownerKeySalt, password.length);
hashData.set(userBytes, password.length + ownerKeySalt.length); hashData.set(userBytes, password.length + ownerKeySalt.length);
const key = calculateSHA256(hashData, 0, hashData.length); const key = this._hash(password, hashData, userBytes);
const cipher = new AES256Cipher(key); const cipher = new AES256Cipher(key);
return cipher.decryptBlock(ownerEncryption, false, new Uint8Array(16)); return cipher.decryptBlock(ownerEncryption, false, new Uint8Array(16));
} }
@ -665,14 +678,20 @@ class PDF17 {
hashData.set(password, 0); hashData.set(password, 0);
hashData.set(userKeySalt, password.length); hashData.set(userKeySalt, password.length);
// `key` is the decryption key for the UE string. // `key` is the decryption key for the UE string.
const key = calculateSHA256(hashData, 0, hashData.length); const key = this._hash(password, hashData, []);
const cipher = new AES256Cipher(key); const cipher = new AES256Cipher(key);
return cipher.decryptBlock(userEncryption, false, new Uint8Array(16)); return cipher.decryptBlock(userEncryption, false, new Uint8Array(16));
} }
} }
class PDF20 { class PDF17 extends PDFBase {
#hash(password, input, userBytes) { _hash(password, input, userBytes) {
return calculateSHA256(input, 0, input.length);
}
}
class PDF20 extends PDFBase {
_hash(password, input, userBytes) {
// This refers to Algorithm 2.B as defined in ISO 32000-2. // This refers to Algorithm 2.B as defined in ISO 32000-2.
let k = calculateSHA256(input, 0, input.length).subarray(0, 32); let k = calculateSHA256(input, 0, input.length).subarray(0, 32);
let e = [0]; let e = [0];
@ -713,43 +732,6 @@ class PDF20 {
} }
return k.subarray(0, 32); return k.subarray(0, 32);
} }
checkOwnerPassword(password, ownerValidationSalt, userBytes, ownerPassword) {
const hashData = new Uint8Array(password.length + 56);
hashData.set(password, 0);
hashData.set(ownerValidationSalt, password.length);
hashData.set(userBytes, password.length + ownerValidationSalt.length);
const result = this.#hash(password, hashData, userBytes);
return isArrayEqual(result, ownerPassword);
}
checkUserPassword(password, userValidationSalt, userPassword) {
const hashData = new Uint8Array(password.length + 8);
hashData.set(password, 0);
hashData.set(userValidationSalt, password.length);
const result = this.#hash(password, hashData, []);
return isArrayEqual(result, userPassword);
}
getOwnerKey(password, ownerKeySalt, userBytes, ownerEncryption) {
const hashData = new Uint8Array(password.length + 56);
hashData.set(password, 0);
hashData.set(ownerKeySalt, password.length);
hashData.set(userBytes, password.length + ownerKeySalt.length);
const key = this.#hash(password, hashData, userBytes);
const cipher = new AES256Cipher(key);
return cipher.decryptBlock(ownerEncryption, false, new Uint8Array(16));
}
getUserKey(password, userKeySalt, userEncryption) {
const hashData = new Uint8Array(password.length + 8);
hashData.set(password, 0);
hashData.set(userKeySalt, password.length);
// `key` is the decryption key for the UE string.
const key = this.#hash(password, hashData, []);
const cipher = new AES256Cipher(key);
return cipher.decryptBlock(userEncryption, false, new Uint8Array(16));
}
} }
class CipherTransform { class CipherTransform {