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Add back armor checksum where allowed by the spec

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We need to include the checksum to workaround an GnuPG bug
where data fails to be decoded if the base64 ends with no padding chars (=)
(see https://dev.gnupg.org/T7071)
This commit is contained in:
larabr 2024-04-08 17:03:57 +02:00
parent d1681bb669
commit 279dc07019
9 changed files with 146 additions and 10 deletions
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8
src/cleartext.js
View File

@ -111,9 +111,9 @@ export class CleartextMessage {
* @returns {String | ReadableStream<String>} ASCII armor.
*/
armor(config = defaultConfig) {
const includesNonV6Signatures = this.signature.packets.some(packet => packet.version !== 6);
// emit header if one of the signatures has a version not 6
const emitHeader = this.signature.packets.some(packet => packet.version !== 6);
const hash = emitHeader ?
const hash = includesNonV6Signatures ?
Array.from(new Set(this.signature.packets.map(
packet => enums.read(enums.hash, packet.hashAlgorithm).toUpperCase()
))).join() :
@ -124,7 +124,9 @@ export class CleartextMessage {
text: this.text,
data: this.signature.packets.write()
};
return armor(enums.armor.signed, body, undefined, undefined, undefined, config);
// An ASCII-armored sequence of Signature packets that only includes v6 Signature packets MUST NOT contain a CRC24 footer.
return armor(enums.armor.signed, body, undefined, undefined, undefined, includesNonV6Signatures, config);
}
}

88
src/encoding/armor.js
View File

@ -107,6 +107,78 @@ function addheader(customComment, config) {
return result;
}
/**
* 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:
@ -262,10 +334,13 @@ export function unarmor(input) {
* @param {Integer} [partIndex]
* @param {Integer} [partTotal]
* @param {String} [customComment] - Additional comment to add to the armored string
* @param {Boolean} [withChecksum] - Whether to compute and include the CRC checksum
* (NB: some types of data must not include it, but compliance is left as responsibility of the caller: this function does not carry out any checks)
* @param {Object} [config] - Full configuration, defaults to openpgp.config
* @returns {String | ReadableStream<String>} Armored text.
* @static
*/
export function armor(messageType, body, partIndex, partTotal, customComment, config = defaultConfig) {
export function armor(messageType, body, partIndex, partTotal, customComment, withChecksum = false, config = defaultConfig) {
let text;
let hash;
if (messageType === enums.armor.signed) {
@ -273,18 +348,24 @@ export function armor(messageType, body, partIndex, partTotal, customComment, co
hash = body.hash;
body = body.data;
}
// unless explicitly forbidden by the spec, we need to include the checksum to workaround an GnuPG bug
// where data fails to be decoded if the base64 ends with no padding chars (=) (see https://dev.gnupg.org/T7071)
const maybeBodyClone = withChecksum && stream.passiveClone(body);
const result = [];
switch (messageType) {
case enums.armor.multipartSection:
result.push('-----BEGIN PGP MESSAGE, PART ' + partIndex + '/' + partTotal + '-----\n');
result.push(addheader(customComment, config));
result.push(base64.encode(body));
maybeBodyClone && result.push('=', getCheckSum(maybeBodyClone));
result.push('-----END PGP MESSAGE, PART ' + partIndex + '/' + partTotal + '-----\n');
break;
case enums.armor.multipartLast:
result.push('-----BEGIN PGP MESSAGE, PART ' + partIndex + '-----\n');
result.push(addheader(customComment, config));
result.push(base64.encode(body));
maybeBodyClone && result.push('=', getCheckSum(maybeBodyClone));
result.push('-----END PGP MESSAGE, PART ' + partIndex + '-----\n');
break;
case enums.armor.signed:
@ -294,30 +375,35 @@ export function armor(messageType, body, partIndex, partTotal, customComment, co
result.push('\n-----BEGIN PGP SIGNATURE-----\n');
result.push(addheader(customComment, config));
result.push(base64.encode(body));
maybeBodyClone && result.push('=', getCheckSum(maybeBodyClone));
result.push('-----END PGP SIGNATURE-----\n');
break;
case enums.armor.message:
result.push('-----BEGIN PGP MESSAGE-----\n');
result.push(addheader(customComment, config));
result.push(base64.encode(body));
maybeBodyClone && result.push('=', getCheckSum(maybeBodyClone));
result.push('-----END PGP MESSAGE-----\n');
break;
case enums.armor.publicKey:
result.push('-----BEGIN PGP PUBLIC KEY BLOCK-----\n');
result.push(addheader(customComment, config));
result.push(base64.encode(body));
maybeBodyClone && result.push('=', getCheckSum(maybeBodyClone));
result.push('-----END PGP PUBLIC KEY BLOCK-----\n');
break;
case enums.armor.privateKey:
result.push('-----BEGIN PGP PRIVATE KEY BLOCK-----\n');
result.push(addheader(customComment, config));
result.push(base64.encode(body));
maybeBodyClone && result.push('=', getCheckSum(maybeBodyClone));
result.push('-----END PGP PRIVATE KEY BLOCK-----\n');
break;
case enums.armor.signature:
result.push('-----BEGIN PGP SIGNATURE-----\n');
result.push(addheader(customComment, config));
result.push(base64.encode(body));
maybeBodyClone && result.push('=', getCheckSum(maybeBodyClone));
result.push('-----END PGP SIGNATURE-----\n');
break;
}

4
src/key/key.js
View File

@ -612,7 +612,9 @@ class Key {
const revocationSignature = await helper.getLatestValidSignature(this.revocationSignatures, this.keyPacket, enums.signature.keyRevocation, dataToVerify, date, config);
const packetlist = new PacketList();
packetlist.push(revocationSignature);
return armor(enums.armor.publicKey, packetlist.write(), null, null, 'This is a revocation certificate');
// An ASCII-armored Transferable Public Key packet sequence of a v6 key MUST NOT contain a CRC24 footer.
const v6Key = this.keyPacket.version === 6;
return armor(enums.armor.publicKey, packetlist.write(), null, null, 'This is a revocation certificate', !v6Key);
}
/**

4
src/key/private_key.js
View File

@ -64,7 +64,9 @@ class PrivateKey extends PublicKey {
* @returns {ReadableStream<String>} ASCII armor.
*/
armor(config = defaultConfig) {
return armor(enums.armor.privateKey, this.toPacketList().write(), undefined, undefined, undefined, config);
// An ASCII-armored Transferable Public Key packet sequence of a v6 key MUST NOT contain a CRC24 footer.
const v6Key = this.keyPacket.version === 6;
return armor(enums.armor.privateKey, this.toPacketList().write(), undefined, undefined, undefined, !v6Key, config);
}
/**

4
src/key/public_key.js
View File

@ -61,7 +61,9 @@ class PublicKey extends Key {
* @returns {ReadableStream<String>} ASCII armor.
*/
armor(config = defaultConfig) {
return armor(enums.armor.publicKey, this.toPacketList().write(), undefined, undefined, undefined, config);
// An ASCII-armored Transferable Public Key packet sequence of a v6 key MUST NOT contain a CRC24 footer.
const v6Key = this.keyPacket.version === 6;
return armor(enums.armor.publicKey, this.toPacketList().write(), undefined, undefined, undefined, !v6Key, config);
}
}

8
src/message.js
View File

@ -680,7 +680,13 @@ export class Message {
* @returns {ReadableStream<String>} ASCII armor.
*/
armor(config = defaultConfig) {
return armor(enums.armor.message, this.write(), null, null, null, config);
const trailingPacket = this.packets[this.packets.length - 1];
// An ASCII-armored Encrypted Message packet sequence that ends in an v2 SEIPD packet MUST NOT contain a CRC24 footer.
// An ASCII-armored sequence of Signature packets that only includes v6 Signature packets MUST NOT contain a CRC24 footer.
const includeArmorChecksum = trailingPacket.constructor.tag === SymEncryptedIntegrityProtectedDataPacket.tag ?
trailingPacket.version !== 2 :
this.packets.some(packet => packet.constructor.tag === SignaturePacket.tag && packet.version !== 6);
return armor(enums.armor.message, this.write(), null, null, null, includeArmorChecksum, config);
}
}

4
src/signature.js
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@ -49,7 +49,9 @@ export class Signature {
* @returns {ReadableStream<String>} ASCII armor.
*/
armor(config = defaultConfig) {
return armor(enums.armor.signature, this.write(), undefined, undefined, undefined, config);
// An ASCII-armored sequence of Signature packets that only includes v6 Signature packets MUST NOT contain a CRC24 footer.
const includesNonV6Signatures = this.packets.some(packet => packet.constructor.tag === SignaturePacket.tag && packet.version !== 6);
return armor(enums.armor.signature, this.write(), undefined, undefined, undefined, includesNonV6Signatures, config);
}
/**

34
test/general/armor.js
View File

@ -255,6 +255,40 @@ export default () => describe('ASCII armor', function() {
expect(msg.text).to.equal('\r\nsign this');
});
it('Selectively output CRC checksum', async function () {
const includesArmorChecksum = armoredData => {
const lines = armoredData.split('\n');
const lastDataLine = lines[lines.length - 3];
return (lastDataLine[0] === '=' && lastDataLine.length === 5);
};
// unless explicitly forbidden by the spec, we include the checksum to workaround an GnuPG bug (https://dev.gnupg.org/T7071)
const { privateKey: v4Key } = await openpgp.generateKey({ userIDs: { email: 'v4@armor.test' }, format: 'object' });
expect(includesArmorChecksum(v4Key.armor())).to.be.true;
const { privateKey: v6Key } = await openpgp.generateKey({ userIDs: { email: 'v6@armor.test' }, config: { v6Keys: true, aeadProtect: true }, format: 'object' });
expect(includesArmorChecksum(v6Key.armor())).to.be.false;
const messageWithSEIPDv1 = await openpgp.encrypt({ message: await openpgp.createMessage({ text: 'test' }), encryptionKeys: v4Key });
expect(includesArmorChecksum(messageWithSEIPDv1)).to.be.true;
const messageWithSEIPDv2 = await openpgp.encrypt({ message: await openpgp.createMessage({ text: 'test' }), encryptionKeys: v6Key });
expect(includesArmorChecksum(messageWithSEIPDv2)).to.be.false;
const signatureV4V6 = await openpgp.sign({ message: await openpgp.createMessage({ text: 'test' }), signingKeys: [v4Key, v6Key] });
expect(includesArmorChecksum(signatureV4V6)).to.be.true;
const signatureV6 = await openpgp.sign({ message: await openpgp.createMessage({ text: 'test' }), signingKeys: v6Key });
expect(includesArmorChecksum(signatureV6)).to.be.false;
const detachedSignatureV4V6 = await openpgp.sign({ message: await openpgp.createMessage({ text: 'test' }), signingKeys: [v4Key, v6Key], detached: true });
expect(includesArmorChecksum(detachedSignatureV4V6)).to.be.true;
const detachedSignatureV6 = await openpgp.sign({ message: await openpgp.createMessage({ text: 'test' }), signingKeys: v6Key, detached: true });
expect(includesArmorChecksum(detachedSignatureV6)).to.be.false;
const cleartextSignatureV4V6 = await openpgp.sign({ message: await openpgp.createCleartextMessage({ text: 'test' }), signingKeys: [v4Key, v6Key] });
expect(includesArmorChecksum(cleartextSignatureV4V6)).to.be.true;
const cleartextSignatureV6 = await openpgp.sign({ message: await openpgp.createCleartextMessage({ text: 'test' }), signingKeys: v6Key });
expect(includesArmorChecksum(cleartextSignatureV6)).to.be.false;
});
it('Do not add extraneous blank line when base64 ends on line break', async function () {
const pubKey = `-----BEGIN PGP PUBLIC KEY BLOCK-----

2
test/general/key.js
View File

@ -4024,7 +4024,7 @@ CNa5yq6lyexhsn2Vs8DsX+SOSUyNJiy5FyIJ
const input = await openpgp.unarmor(revocation_certificate_arm4);
const packetlist = await openpgp.PacketList.fromBinary(input.data, util.constructAllowedPackets([openpgp.SignaturePacket]), openpgp.config);
const armored = openpgp.armor(openpgp.enums.armor.publicKey, packetlist.write());
const armored = openpgp.armor(openpgp.enums.armor.publicKey, packetlist.write(), undefined, undefined, undefined, true);
expect(revocationCertificate.replace(/^Comment: .*$\n/mg, '')).to.equal(armored.replace(/^Comment: .*$\n/mg, ''));
});