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Truncate SVR2 IDs to 16 bytes rather than 10.

This commit is contained in:
gram-signal 2023-03-30 17:19:18 -06:00 committed by GitHub
parent 84355963f9
commit 781cd0ca3f
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 28 additions and 7 deletions
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23
service/src/main/java/org/whispersystems/textsecuregcm/auth/ExternalServiceCredentialsGenerator.java
View File

@ -18,8 +18,6 @@ import org.apache.commons.lang3.Validate;
public class ExternalServiceCredentialsGenerator {
private static final int TRUNCATE_LENGTH = 10;
private static final String DELIMITER = ":";
private final byte[] key;
@ -32,6 +30,7 @@ public class ExternalServiceCredentialsGenerator {
private final Clock clock;
private final int truncateLength;
public static ExternalServiceCredentialsGenerator.Builder builder(final byte[] key) {
return new Builder(key);
@ -42,12 +41,14 @@ public class ExternalServiceCredentialsGenerator {
final byte[] userDerivationKey,
final boolean prependUsername,
final boolean truncateSignature,
final Clock clock) {
final Clock clock,
final int truncateLength) {
this.key = requireNonNull(key);
this.userDerivationKey = requireNonNull(userDerivationKey);
this.prependUsername = prependUsername;
this.truncateSignature = truncateSignature;
this.clock = requireNonNull(clock);
this.truncateLength = truncateLength;
}
/**
@ -66,7 +67,7 @@ public class ExternalServiceCredentialsGenerator {
*/
public ExternalServiceCredentials generateFor(final String identity) {
final String username = shouldDeriveUsername()
? hmac256TruncatedToHexString(userDerivationKey, identity, TRUNCATE_LENGTH)
? hmac256TruncatedToHexString(userDerivationKey, identity, truncateLength)
: identity;
final long currentTimeSeconds = currentTimeSeconds();
@ -74,7 +75,7 @@ public class ExternalServiceCredentialsGenerator {
final String dataToSign = username + DELIMITER + currentTimeSeconds;
final String signature = truncateSignature
? hmac256TruncatedToHexString(key, dataToSign, TRUNCATE_LENGTH)
? hmac256TruncatedToHexString(key, dataToSign, truncateLength)
: hmac256ToHexString(key, dataToSign);
final String token = (prependUsername ? dataToSign : currentTimeSeconds) + DELIMITER + signature;
@ -131,7 +132,7 @@ public class ExternalServiceCredentialsGenerator {
final String signedData = credentials.username() + DELIMITER + timestampSeconds;
final String expectedSignature = truncateSignature
? hmac256TruncatedToHexString(key, signedData, TRUNCATE_LENGTH)
? hmac256TruncatedToHexString(key, signedData, truncateLength)
: hmac256ToHexString(key, signedData);
// if the signature is valid it's safe to parse the `timestampSeconds` string into Long
@ -171,6 +172,8 @@ public class ExternalServiceCredentialsGenerator {
private boolean truncateSignature = true;
private int truncateLength = 10;
private Clock clock = Clock.systemUTC();
@ -189,6 +192,12 @@ public class ExternalServiceCredentialsGenerator {
return this;
}
public Builder withTruncateLength(int truncateLength) {
Validate.inclusiveBetween(10, 32, truncateLength);
this.truncateLength = truncateLength;
return this;
}
public Builder prependUsername(final boolean prependUsername) {
this.prependUsername = prependUsername;
return this;
@ -201,7 +210,7 @@ public class ExternalServiceCredentialsGenerator {
public ExternalServiceCredentialsGenerator build() {
return new ExternalServiceCredentialsGenerator(
key, userDerivationKey, prependUsername, truncateSignature, clock);
key, userDerivationKey, prependUsername, truncateSignature, clock, truncateLength);
}
}
}

1
service/src/main/java/org/whispersystems/textsecuregcm/controllers/SecureValueRecovery2Controller.java
View File

@ -29,6 +29,7 @@ public class SecureValueRecovery2Controller {
.builder(cfg.userAuthenticationTokenSharedSecret())
.withUserDerivationKey(cfg.userIdTokenSharedSecret())
.prependUsername(false)
.withTruncateLength(16)
.build();
}

11
service/src/test/java/org/whispersystems/textsecuregcm/tests/auth/ExternalServiceCredentialsGeneratorTest.java
View File

@ -112,4 +112,15 @@ class ExternalServiceCredentialsGeneratorTest {
assertEquals(generator.validateAndGetTimestamp(credentials, elapsedSeconds + 1).orElseThrow(), TIME_SECONDS);
assertTrue(generator.validateAndGetTimestamp(credentials, elapsedSeconds - 1).isEmpty());
}
@Test
public void testTruncateLength() throws Exception {
final ExternalServiceCredentialsGenerator generator = ExternalServiceCredentialsGenerator.builder(new byte[32])
.withUserDerivationKey(new byte[32])
.withTruncateLength(14)
.build();
final ExternalServiceCredentials creds = generator.generateFor(E164);
assertEquals(14*2 /* 2 chars per byte, because hex */, creds.username().length());
assertEquals("805b84df7eff1e8fe1baf0c6e838", creds.username());
}
}