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Handle both given and family name in decrypted profile name

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* Decrypt given and family names from profile name string
* Handle both given and family name from decrypted profile name
* Ensure we properly handle profiles with no family name
This commit is contained in:
Scott Nonnenberg 2020-01-13 14:28:28 -08:00 • committed by Ken Powers
parent 4f50c0b093
commit 11266cb775
9 changed files with 326 additions and 39 deletions
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37
libtextsecure/crypto.js
View file

@ -9,7 +9,7 @@
const PROFILE_IV_LENGTH = 12; // bytes
const PROFILE_KEY_LENGTH = 32; // bytes
const PROFILE_TAG_LENGTH = 128; // bits
const PROFILE_NAME_PADDED_LENGTH = 26; // bytes
const PROFILE_NAME_PADDED_LENGTH = 53; // bytes
function verifyDigest(data, theirDigest) {
return crypto.subtle.digest({ name: 'SHA-256' }, data).then(ourDigest => {
@ -208,18 +208,39 @@
'base64'
).toArrayBuffer();
return textsecure.crypto.decryptProfile(data, key).then(decrypted => {
// unpad
const padded = new Uint8Array(decrypted);
let i;
for (i = padded.length; i > 0; i -= 1) {
if (padded[i - 1] !== 0x00) {
// Given name is the start of the string to the first null character
let givenEnd;
for (givenEnd = 0; givenEnd < padded.length; givenEnd += 1) {
if (padded[givenEnd] === 0x00) {
break;
}
}
return dcodeIO.ByteBuffer.wrap(padded)
.slice(0, i)
.toArrayBuffer();
// Family name is the next chunk of non-null characters after that first null
let familyEnd;
for (
familyEnd = givenEnd + 1;
familyEnd < padded.length;
familyEnd += 1
) {
if (padded[familyEnd] === 0x00) {
break;
}
}
const foundFamilyName = familyEnd > givenEnd + 1;
return {
given: dcodeIO.ByteBuffer.wrap(padded)
.slice(0, givenEnd)
.toArrayBuffer(),
family: foundFamilyName
? dcodeIO.ByteBuffer.wrap(padded)
.slice(givenEnd + 1, familyEnd)
.toArrayBuffer()
: null,
};
});
},

80
libtextsecure/test/crypto_test.js
View file

@ -1,7 +1,7 @@
/* global libsignal, textsecure */
describe('encrypting and decrypting profile data', () => {
const NAME_PADDED_LENGTH = 26;
const NAME_PADDED_LENGTH = 53;
describe('encrypting and decrypting profile names', () => {
it('pads, encrypts, decrypts, and unpads a short string', () => {
const name = 'Alice';
@ -14,11 +14,78 @@ describe('encrypting and decrypting profile data', () => {
assert(encrypted.byteLength === NAME_PADDED_LENGTH + 16 + 12);
return textsecure.crypto
.decryptProfileName(encrypted, key)
.then(decrypted => {
.then(({ given, family }) => {
assert.strictEqual(family, null);
assert.strictEqual(
dcodeIO.ByteBuffer.wrap(decrypted).toString('utf8'),
dcodeIO.ByteBuffer.wrap(given).toString('utf8'),
name
);
});
});
});
it('handles a given name of the max, 53 characters', () => {
const name = '01234567890123456789012345678901234567890123456789123';
const buffer = dcodeIO.ByteBuffer.wrap(name).toArrayBuffer();
const key = libsignal.crypto.getRandomBytes(32);
return textsecure.crypto
.encryptProfileName(buffer, key)
.then(encrypted => {
assert(encrypted.byteLength === NAME_PADDED_LENGTH + 16 + 12);
return textsecure.crypto
.decryptProfileName(encrypted, key)
.then(({ given, family }) => {
assert.strictEqual(
dcodeIO.ByteBuffer.wrap(given).toString('utf8'),
name
);
assert.strictEqual(family, null);
});
});
});
it('handles family/given name of the max, 53 characters', () => {
const name = '01234567890123456789\u000001234567890123456789012345678912';
const buffer = dcodeIO.ByteBuffer.wrap(name).toArrayBuffer();
const key = libsignal.crypto.getRandomBytes(32);
return textsecure.crypto
.encryptProfileName(buffer, key)
.then(encrypted => {
assert(encrypted.byteLength === NAME_PADDED_LENGTH + 16 + 12);
return textsecure.crypto
.decryptProfileName(encrypted, key)
.then(({ given, family }) => {
assert.strictEqual(
dcodeIO.ByteBuffer.wrap(given).toString('utf8'),
'01234567890123456789'
);
assert.strictEqual(
dcodeIO.ByteBuffer.wrap(family).toString('utf8'),
'01234567890123456789012345678912'
);
});
});
});
it('handles a string with family/given name', () => {
const name = 'Alice\0Jones';
const buffer = dcodeIO.ByteBuffer.wrap(name).toArrayBuffer();
const key = libsignal.crypto.getRandomBytes(32);
return textsecure.crypto
.encryptProfileName(buffer, key)
.then(encrypted => {
assert(encrypted.byteLength === NAME_PADDED_LENGTH + 16 + 12);
return textsecure.crypto
.decryptProfileName(encrypted, key)
.then(({ given, family }) => {
assert.strictEqual(
dcodeIO.ByteBuffer.wrap(given).toString('utf8'),
'Alice'
);
assert.strictEqual(
dcodeIO.ByteBuffer.wrap(family).toString('utf8'),
'Jones'
);
});
});
});
@ -32,10 +99,11 @@ describe('encrypting and decrypting profile data', () => {
assert(encrypted.byteLength === NAME_PADDED_LENGTH + 16 + 12);
return textsecure.crypto
.decryptProfileName(encrypted, key)
.then(decrypted => {
assert.strictEqual(decrypted.byteLength, 0);
.then(({ given, family }) => {
assert.strictEqual(family, null);
assert.strictEqual(given.byteLength, 0);
assert.strictEqual(
dcodeIO.ByteBuffer.wrap(decrypted).toString('utf8'),
dcodeIO.ByteBuffer.wrap(given).toString('utf8'),
''
);
});