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Remove two-stage check of username availability in reserve/confirm

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This commit is contained in:
Jonathan Klabunde Tomer
2024-01-09 14:01:42 -08:00
committed by GitHub
parent ed972a0037
commit 184cdc0331
5 changed files with 91 additions and 106 deletions
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50
service/src/main/java/org/whispersystems/textsecuregcm/storage/Accounts.java
View File

@@ -439,6 +439,9 @@ public class Accounts extends AbstractDynamoDbStore {
/**
* Reserve a username hash under the account UUID
* @return a future that completes once the username hash has been reserved; may fail with an
* {@link ContestedOptimisticLockException} if the account has been updated or
* {@link UsernameHashNotAvailableException} if the username was taken by someone else
*/
public CompletableFuture<Void> reserveUsernameHash(
final Account account,
@@ -504,7 +507,12 @@ public class Accounts extends AbstractDynamoDbStore {
.build())
.exceptionally(throwable -> {
if (ExceptionUtils.unwrap(throwable) instanceof TransactionCanceledException e) {
if (e.cancellationReasons().stream().map(CancellationReason::code).anyMatch(CONDITIONAL_CHECK_FAILED::equals)) {
// If the constraint table update failed the condition check, the username's taken and we should stop
// trying. However if it was only in the accounts table that the condition check update failed, it's an
// optimistic locking failure (the account was concurrently updated) and we should try again.
if (conditionalCheckFailed(e.cancellationReasons().get(0))) {
throw ExceptionUtils.wrap(new UsernameHashNotAvailableException());
} else if (conditionalCheckFailed(e.cancellationReasons().get(1))) {
throw new ContestedOptimisticLockException();
}
}
@@ -529,7 +537,8 @@ public class Accounts extends AbstractDynamoDbStore {
* @param account to update
* @param usernameHash believed to be available
* @return a future that completes once the username hash has been confirmed; may fail with an
* {@link ContestedOptimisticLockException} if the account has been updated or the username has taken by someone else
* {@link ContestedOptimisticLockException} if the account has been updated or
* {@link UsernameHashNotAvailableException} if the username was taken by someone else
*/
public CompletableFuture<Void> confirmUsernameHash(final Account account, final byte[] usernameHash, @Nullable final byte[] encryptedUsername) {
final Timer.Sample sample = Timer.start();
@@ -559,10 +568,15 @@ public class Accounts extends AbstractDynamoDbStore {
return (Void) null;
})
.exceptionally(throwable -> {
if (ExceptionUtils.unwrap(
throwable) instanceof TransactionCanceledException transactionCanceledException) {
if (transactionCanceledException.cancellationReasons().stream().map(CancellationReason::code)
.anyMatch(CONDITIONAL_CHECK_FAILED::equals)) {
if (ExceptionUtils.unwrap(throwable) instanceof TransactionCanceledException e) {
// If the constraint table update failed the condition check, the username's taken and we should stop
// trying. However if it was only in the accounts table that the condition check update failed, it's an
// optimistic locking failure (the account was concurrently updated) and we should try again.
// NOTE: the fixed indices here must be kept in sync with the creation of the TransactWriteItems in
// buildConfirmUsernameHashRequest!
if (conditionalCheckFailed(e.cancellationReasons().get(0))) {
throw ExceptionUtils.wrap(new UsernameHashNotAvailableException());
} else if (conditionalCheckFailed(e.cancellationReasons().get(1))) {
throw new ContestedOptimisticLockException();
}
}
@@ -603,6 +617,8 @@ public class Accounts extends AbstractDynamoDbStore {
final byte[] usernameHash = updatedAccount.getUsernameHash()
.orElseThrow(() -> new IllegalArgumentException("Account must have a username hash"));
// NOTE: the order in which writeItems are added to the list is significant, and must be kept in sync with the catch block in confirmUsernameHash!
// add the username hash to the constraint table, wiping out the ttl if we had already reserved the hash
writeItems.add(TransactWriteItem.builder()
.put(Put.builder()
@@ -908,28 +924,6 @@ public class Accounts extends AbstractDynamoDbStore {
});
}
public CompletableFuture<Boolean> usernameHashAvailable(final byte[] username) {
return usernameHashAvailable(Optional.empty(), username);
}
public CompletableFuture<Boolean> usernameHashAvailable(final Optional<UUID> accountUuid, final byte[] usernameHash) {
return itemByKeyAsync(usernamesConstraintTableName, ATTR_USERNAME_HASH, AttributeValues.fromByteArray(usernameHash))
.thenApply(maybeUsernameHashItem -> maybeUsernameHashItem
.map(item -> {
if (AttributeValues.getLong(item, ATTR_TTL, Long.MAX_VALUE) < clock.instant().getEpochSecond()) {
// username hash was reserved, but has expired
return true;
}
// username hash is reserved by us
return !AttributeValues.getBool(item, ATTR_CONFIRMED, true) && accountUuid
.map(AttributeValues.getUUID(item, KEY_ACCOUNT_UUID, new UUID(0, 0))::equals)
.orElse(false);
})
// If no item was found, then the username hash is free
.orElse(true));
}
@Nonnull
public Optional<Account> getByE164(final String number) {
return getByIndirectLookup(

35
service/src/main/java/org/whispersystems/textsecuregcm/storage/AccountsManager.java
View File

@@ -579,23 +579,17 @@ public class AccountsManager {
}
private CompletableFuture<byte[]> checkAndReserveNextUsernameHash(final Account account, final Queue<byte[]> requestedUsernameHashes) {
final byte[] usernameHash;
final byte[] usernameHash = requestedUsernameHashes.remove();
try {
usernameHash = requestedUsernameHashes.remove();
} catch (final NoSuchElementException e) {
return CompletableFuture.failedFuture(new UsernameHashNotAvailableException());
}
return accounts.usernameHashAvailable(usernameHash)
.thenCompose(usernameHashAvailable -> {
if (usernameHashAvailable) {
return accounts.reserveUsernameHash(account, usernameHash, USERNAME_HASH_RESERVATION_TTL_MINUTES)
.thenApply(ignored -> usernameHash);
} else {
return checkAndReserveNextUsernameHash(account, requestedUsernameHashes);
}
});
return accounts.reserveUsernameHash(account, usernameHash, USERNAME_HASH_RESERVATION_TTL_MINUTES)
.thenApply(ignored -> usernameHash)
.exceptionallyComposeAsync(
throwable -> {
if (ExceptionUtils.unwrap(throwable) instanceof UsernameHashNotAvailableException && !requestedUsernameHashes.isEmpty()) {
return checkAndReserveNextUsernameHash(account, requestedUsernameHashes);
}
return CompletableFuture.failedFuture(throwable);
});
}
/**
@@ -629,14 +623,7 @@ public class AccountsManager {
.thenCompose(ignored -> updateWithRetriesAsync(
account,
a -> true,
a -> accounts.usernameHashAvailable(Optional.of(account.getUuid()), reservedUsernameHash)
.thenCompose(usernameHashAvailable -> {
if (!usernameHashAvailable) {
return CompletableFuture.failedFuture(new UsernameHashNotAvailableException());
}
return accounts.confirmUsernameHash(a, reservedUsernameHash, encryptedUsername);
}),
a -> accounts.confirmUsernameHash(a, reservedUsernameHash, encryptedUsername),
() -> accounts.getByAccountIdentifierAsync(account.getUuid()).thenApply(Optional::orElseThrow),
AccountChangeValidator.USERNAME_CHANGE_VALIDATOR,
MAX_UPDATE_ATTEMPTS