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Remove XsrfTokenManager fallback for validating legacy tokens

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This is the third step of migrating to the new format: removing support
for the legacy format.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=150512556
This commit is contained in:
nickfelt 2017-03-17 19:52:12 -07:00 • committed by Ben McIlwain
parent 09f619cce2
commit 232132eac0
2 changed files with 18 additions and 54 deletions
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65
java/google/registry/security/XsrfTokenManager.java
View file

@ -14,7 +14,6 @@
package google.registry.security;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.io.BaseEncoding.base64Url;
import static google.registry.util.PreconditionsUtils.checkArgumentNotNull;
import static java.nio.charset.StandardCharsets.UTF_8;
@ -23,7 +22,6 @@ import static org.joda.time.DateTimeZone.UTC;
import com.google.appengine.api.users.UserService;
import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableSet;
import com.google.common.hash.Hashing;
import google.registry.model.server.ServerSecret;
import google.registry.util.Clock;
@ -45,9 +43,6 @@ public final class XsrfTokenManager {
/** Token version identifier for version 1. */
private static final String VERSION_1 = "1";
/** Legacy scope values that will be supported during the scope removal process. */
private static final ImmutableSet<String> LEGACY_SCOPES = ImmutableSet.of("admin", "console");
private static final FormattingLogger logger = FormattingLogger.getLoggerForCallerClass();
private final Clock clock;
@ -82,36 +77,18 @@ public final class XsrfTokenManager {
return Joiner.on(':').join(VERSION_1, timestampMillis, hmac);
}
/**
* Computes the hash payload portion of a legacy-style XSRF token.
*
* <p>The result is a Base64-encoded SHA-256 hash of a string containing the secret, email, scope
* and creation time, separated by tabs.
*/
private static String computeLegacyHash(long creationTime, String scope, String userEmail) {
checkArgument(LEGACY_SCOPES.contains(scope), "Invalid scope value: %s", scope);
String token =
Joiner.on('\t').join(ServerSecret.get().asUuid(), userEmail, scope, creationTime);
return base64Url().encode(Hashing.sha256()
.newHasher(token.length())
.putString(token, UTF_8)
.hash()
.asBytes());
}
/**
* Validates an XSRF token against the current logged-in user.
*
* This accepts both legacy-style and new-style XSRF tokens. For legacy-style tokens, it will
* accept tokens generated with any scope from {@link #LEGACY_SCOPES}.
*/
/** Validates an XSRF token against the current logged-in user. */
public boolean validateToken(String token) {
checkArgumentNotNull(token);
List<String> tokenParts = Splitter.on(':').splitToList(token);
if (tokenParts.size() < 2) {
if (tokenParts.size() != 3) {
logger.warningfmt("Malformed XSRF token: %s", token);
return false;
}
if (!tokenParts.get(0).equals(VERSION_1)) {
logger.warningfmt("Unrecognized version in XSRF token: %s", token);
return false;
}
String timePart = tokenParts.get(1);
long timestampMillis;
try {
@ -127,32 +104,14 @@ public final class XsrfTokenManager {
String currentUserEmail =
userService.isUserLoggedIn() ? userService.getCurrentUser().getEmail() : "";
// Reconstruct the token to verify validity, using version 1 format if detected.
if (tokenParts.get(0).equals(VERSION_1)) {
String reconstructedToken =
encodeToken(ServerSecret.get().asBytes(), currentUserEmail, timestampMillis);
if (!token.equals(reconstructedToken)) {
logger.warningfmt(
"Reconstructed XSRF mismatch (got != expected): %s != %s", token, reconstructedToken);
return false;
}
return true;
} else {
// TODO(b/35388772): remove this fallback once we no longer generate legacy tokens.
// Fall back to the legacy format, and try the few possible scopes.
String hash = tokenParts.get(0);
ImmutableSet.Builder<String> reconstructedTokenCandidates = new ImmutableSet.Builder<>();
for (String scope : LEGACY_SCOPES) {
String reconstructedHash = computeLegacyHash(timestampMillis, scope, currentUserEmail);
reconstructedTokenCandidates.add(reconstructedHash);
if (hash.equals(reconstructedHash)) {
return true;
}
}
// Reconstruct the token to verify validity.
String reconstructedToken =
encodeToken(ServerSecret.get().asBytes(), currentUserEmail, timestampMillis);
if (!token.equals(reconstructedToken)) {
logger.warningfmt(
"Reconstructed XSRF mismatch: %s matches none of %s",
hash, reconstructedTokenCandidates.build());
"Reconstructed XSRF mismatch (got != expected): %s != %s", token, reconstructedToken);
return false;
}
return true;
}
}