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Remove armor checksum check

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The crypto refresh says that we MUST NOT reject messages where the
CRC24 checksum is incorrect. So, we remove the check for it.

Also, remove the checksumRequired config.
This commit is contained in:
Daniel Huigens
2022-12-13 15:04:07 +01:00
committed by larabr
parent 6f1eb06119
commit 939622e827
6 changed files with 47 additions and 238 deletions
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91
src/encoding/armor.js
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@@ -108,79 +108,6 @@ function addheader(customComment, config) {
}
/**
* Calculates a checksum over the given data and returns it base64 encoded
* @param {String | ReadableStream<String>} data - Data to create a CRC-24 checksum for
* @returns {String | ReadableStream<String>} Base64 encoded checksum.
* @private
*/
function getCheckSum(data) {
const crc = createcrc24(data);
return base64.encode(crc);
}
// https://create.stephan-brumme.com/crc32/#slicing-by-8-overview
const crc_table = [
new Array(0xFF),
new Array(0xFF),
new Array(0xFF),
new Array(0xFF)
];
for (let i = 0; i <= 0xFF; i++) {
let crc = i << 16;
for (let j = 0; j < 8; j++) {
crc = (crc << 1) ^ ((crc & 0x800000) !== 0 ? 0x864CFB : 0);
}
crc_table[0][i] =
((crc & 0xFF0000) >> 16) |
(crc & 0x00FF00) |
((crc & 0x0000FF) << 16);
}
for (let i = 0; i <= 0xFF; i++) {
crc_table[1][i] = (crc_table[0][i] >> 8) ^ crc_table[0][crc_table[0][i] & 0xFF];
}
for (let i = 0; i <= 0xFF; i++) {
crc_table[2][i] = (crc_table[1][i] >> 8) ^ crc_table[0][crc_table[1][i] & 0xFF];
}
for (let i = 0; i <= 0xFF; i++) {
crc_table[3][i] = (crc_table[2][i] >> 8) ^ crc_table[0][crc_table[2][i] & 0xFF];
}
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView#Endianness
const isLittleEndian = (function() {
const buffer = new ArrayBuffer(2);
new DataView(buffer).setInt16(0, 0xFF, true /* littleEndian */);
// Int16Array uses the platform's endianness.
return new Int16Array(buffer)[0] === 0xFF;
}());
/**
* Internal function to calculate a CRC-24 checksum over a given string (data)
* @param {String | ReadableStream<String>} input - Data to create a CRC-24 checksum for
* @returns {Uint8Array | ReadableStream<Uint8Array>} The CRC-24 checksum.
* @private
*/
function createcrc24(input) {
let crc = 0xCE04B7;
return stream.transform(input, value => {
const len32 = isLittleEndian ? Math.floor(value.length / 4) : 0;
const arr32 = new Uint32Array(value.buffer, value.byteOffset, len32);
for (let i = 0; i < len32; i++) {
crc ^= arr32[i];
crc =
crc_table[0][(crc >> 24) & 0xFF] ^
crc_table[1][(crc >> 16) & 0xFF] ^
crc_table[2][(crc >> 8) & 0xFF] ^
crc_table[3][(crc >> 0) & 0xFF];
}
for (let i = len32 * 4; i < value.length; i++) {
crc = (crc >> 8) ^ crc_table[0][(crc & 0xFF) ^ value[i]];
}
}, () => new Uint8Array([crc, crc >> 8, crc >> 16]));
}
/**
* Verify armored headers. crypto-refresh-06, section 6.2:
* "An OpenPGP implementation may consider improperly formatted Armor
@@ -321,24 +248,6 @@ export function unarmor(input, config = defaultConfig) {
await writer.abort(e);
}
}));
data = stream.transformPair(data, async (readable, writable) => {
const checksumVerified = stream.readToEnd(getCheckSum(stream.passiveClone(readable)));
checksumVerified.catch(() => {});
await stream.pipe(readable, writable, {
preventClose: true
});
const writer = stream.getWriter(writable);
try {
const checksumVerifiedString = (await checksumVerified).replace('\n', '');
if (checksum !== checksumVerifiedString && (checksum || config.checksumRequired)) {
throw new Error('Ascii armor integrity check failed');
}
await writer.ready;
await writer.close();
} catch (e) {
await writer.abort(e);
}
});
} catch (e) {
reject(e);
}