Merge pull request #76 from IABTechLab/aaq-UID2-3335-app-domain-name-…

…check-bidstream Support Domain or App name check in bidstream client
IABTechLab · Oct 10, 2024 · a94bb40 · a94bb40
2 parents 33fab07 + 7e13212
commit a94bb40
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Showing 10 changed files with 353 additions and 23 deletions.
diff --git a/src/main/java/com/uid2/client/BidstreamClient.java b/src/main/java/com/uid2/client/BidstreamClient.java
@@ -9,12 +9,12 @@ public BidstreamClient(String baseUrl, String clientApiKey, String base64SecretK
         tokenHelper = new TokenHelper(baseUrl, clientApiKey, base64SecretKey);
     }
 
-    public DecryptionResponse decryptTokenIntoRawUid(String token, String domainNameFromBidRequest) {
-        return tokenHelper.decrypt(token, Instant.now(), domainNameFromBidRequest, ClientType.BIDSTREAM);
+    public DecryptionResponse decryptTokenIntoRawUid(String token, String domainOrAppNameFromBidRequest) {
+        return tokenHelper.decrypt(token, Instant.now(), domainOrAppNameFromBidRequest, ClientType.BIDSTREAM);
     }
 
-    DecryptionResponse decryptTokenIntoRawUid(String token, String domainNameFromBidRequest, Instant now) {
-        return tokenHelper.decrypt(token, now, domainNameFromBidRequest, ClientType.BIDSTREAM);
+    public DecryptionResponse decryptTokenIntoRawUid(String token, String domainOrAppNameFromBidRequest, Instant now) {
+        return tokenHelper.decrypt(token, now, domainOrAppNameFromBidRequest, ClientType.BIDSTREAM);
     }
 
     public RefreshResponse refresh() {

diff --git a/src/main/java/com/uid2/client/DecryptionStatus.java b/src/main/java/com/uid2/client/DecryptionStatus.java
@@ -47,5 +47,9 @@ public enum DecryptionStatus {
      /**
       * INVALID_TOKEN_LIFETIME: The token has invalid timestamps.
       */
-    INVALID_TOKEN_LIFETIME
+    INVALID_TOKEN_LIFETIME,
+     /**
+      * DOMAIN_OR_APP_NAME_CHECK_FAILED: The supplied domain name or app name doesn't match with the allowed names of the site/app where this token was generated
+      */
+    DOMAIN_OR_APP_NAME_CHECK_FAILED
 }
diff --git a/src/main/java/com/uid2/client/KeyContainer.java b/src/main/java/com/uid2/client/KeyContainer.java
@@ -8,6 +8,7 @@ class KeyContainer {
     private final HashMap<Long, Key> keys = new HashMap<>();
     private final HashMap<Integer, List<Key>> keysBySite = new HashMap<>(); //for legacy /key/latest
     private final HashMap<Integer, List<Key>> keysByKeyset = new HashMap<>();
+    private final Map<Integer, Site> siteIdToSite = new HashMap<>();
     private Instant latestKeyExpiry;
     private int callerSiteId;
     private int masterKeysetId;
@@ -38,7 +39,7 @@ class KeyContainer {
         }
     }
 
-    KeyContainer(int callerSiteId, int masterKeysetId, int defaultKeysetId, long tokenExpirySeconds, List<Key> keyList, IdentityScope identityScope, long maxBidstreamLifetimeSeconds, long maxSharingLifetimeSeconds, long allowClockSkewSeconds) {
+    KeyContainer(int callerSiteId, int masterKeysetId, int defaultKeysetId, long tokenExpirySeconds, List<Key> keyList, List<Site> sites, IdentityScope identityScope, long maxBidstreamLifetimeSeconds, long maxSharingLifetimeSeconds, long allowClockSkewSeconds) {
         this.callerSiteId = callerSiteId;
         this.masterKeysetId = masterKeysetId;
         this.defaultKeysetId = defaultKeysetId;
@@ -61,6 +62,10 @@ class KeyContainer {
         for(Map.Entry<Integer, List<Key>> entry : keysByKeyset.entrySet()) {
             entry.getValue().sort(Comparator.comparing(Key::getActivates));
         }
+
+        for (Site site : sites) {
+            this.siteIdToSite.put(site.getId(), site);
+        }
     }
 
 
@@ -82,6 +87,16 @@ public Key getMasterKey(Instant now)
         return getKeysetActiveKey(masterKeysetId, now);
     }
 
+    public boolean isDomainOrAppNameAllowedForSite(int siteId, String domainOrAppName) {
+        if (domainOrAppName == null) {
+            return false;
+        }
+        if (siteIdToSite.containsKey(siteId)) {
+            return siteIdToSite.get(siteId).allowDomainOrAppName(domainOrAppName);
+        }
+        return false;
+    }
+
     private Key getKeysetActiveKey(int keysetId, Instant now)
     {
         List<Key> keyset = keysByKeyset.get(keysetId);

diff --git a/src/main/java/com/uid2/client/KeyParser.java b/src/main/java/com/uid2/client/KeyParser.java
@@ -6,7 +6,9 @@
 import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Base64;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 
 class KeyParser {
@@ -61,10 +63,35 @@ static KeyContainer parse(InputStream stream) {
                 keys.add(key);
             }
 
-            return new KeyContainer(callerSiteId, masterKeysetId, defaultKeysetId, tokenExpirySeconds, keys, identityScope, maxBidstreamLifetimeSeconds, maxSharingLifetimeSeconds, allowClockSkewSeconds);
+            JsonArray sitesJson = body.getAsJsonArray("site_data");
+            List<Site> sites = new ArrayList<>();
+            if (!isNull(sitesJson)) {
+                for (JsonElement siteJson : sitesJson.asList()) {
+                    Site site = getSiteFromJson(siteJson.getAsJsonObject());
+                    if (site != null) {
+                        sites.add(site);
+                    }
+                }
+            }
+
+            return new KeyContainer(callerSiteId, masterKeysetId, defaultKeysetId, tokenExpirySeconds, keys, sites, identityScope, maxBidstreamLifetimeSeconds, maxSharingLifetimeSeconds, allowClockSkewSeconds);
         }
     }
 
+    private static Site getSiteFromJson(JsonObject siteJson) {
+        int siteId = getAsInt(siteJson, "id");
+        if (siteId == 0) {
+            return null;
+        }
+        JsonArray domainOrAppNamesJArray = siteJson.getAsJsonArray("domain_names");
+        Set<String> domainOrAppNamesSet = new HashSet<>();
+        for (int i = 0; i < domainOrAppNamesJArray.size(); ++i) {
+            domainOrAppNamesSet.add(domainOrAppNamesJArray.get(i).getAsString());
+        }
+
+        return new Site(siteId, domainOrAppNamesSet);
+    }
+
     static private int getAsInt(JsonObject body, String memberName) {
         JsonElement element = body.get(memberName);
         return isNull(element) ? 0 : element.getAsInt();

diff --git a/src/main/java/com/uid2/client/Site.java b/src/main/java/com/uid2/client/Site.java
@@ -0,0 +1,21 @@
+package com.uid2.client;
+
+import java.util.Set;
+
+public class Site {
+    private final int id;
+
+    private final Set<String> domainOrAppNames;
+
+    public int getId() { return id;}
+
+    public Site(int id, Set<String> domainOrAppNames) {
+        this.id = id;
+        this.domainOrAppNames = domainOrAppNames;
+    }
+
+    public boolean allowDomainOrAppName(String domainOrAppName) {
+        // Using streams because HashSet's contains() is case sensitive
+        return domainOrAppNames.stream().anyMatch(domainOrAppName::equalsIgnoreCase);
+    }
+}
diff --git a/src/main/java/com/uid2/client/TokenHelper.java b/src/main/java/com/uid2/client/TokenHelper.java
@@ -15,7 +15,7 @@ class TokenHelper {
         this.uid2Helper = new Uid2Helper(base64SecretKey);
     }
 
-    DecryptionResponse decrypt(String token, Instant now, String domainNameFromBidRequest, ClientType clientType) {
+    DecryptionResponse decrypt(String token, Instant now, String domainOrAppNameFromBidRequest, ClientType clientType) {
         KeyContainer keyContainer = this.container.get();
         if (keyContainer == null) {
             return DecryptionResponse.makeError(DecryptionStatus.NOT_INITIALIZED);
@@ -26,7 +26,7 @@ DecryptionResponse decrypt(String token, Instant now, String domainNameFromBidRe
         }
 
         try {
-            return Uid2Encryption.decrypt(token, keyContainer, now, keyContainer.getIdentityScope(), domainNameFromBidRequest, clientType);
+            return Uid2Encryption.decrypt(token, keyContainer, now, keyContainer.getIdentityScope(), domainOrAppNameFromBidRequest, clientType);
         } catch (Exception e) {
             return DecryptionResponse.makeError(DecryptionStatus.INVALID_PAYLOAD);
         }

diff --git a/src/main/java/com/uid2/client/Uid2Encryption.java b/src/main/java/com/uid2/client/Uid2Encryption.java
@@ -20,7 +20,7 @@ class Uid2Encryption {
     public static final int GCM_AUTHTAG_LENGTH = 16;
     public static final int GCM_IV_LENGTH = 12;
 
-    static DecryptionResponse decrypt(String token, KeyContainer keys, Instant now, IdentityScope identityScope, String domainName, ClientType clientType) throws Exception {
+    static DecryptionResponse decrypt(String token, KeyContainer keys, Instant now, IdentityScope identityScope, String domainOrAppName, ClientType clientType) throws Exception {
 
         if (token.length() < 4)
         {
@@ -33,18 +33,18 @@ static DecryptionResponse decrypt(String token, KeyContainer keys, Instant now,
 
         if (data[0] == 2)
         {
-            return decryptV2(Base64.getDecoder().decode(token), keys, now, domainName, clientType);
+            return decryptV2(Base64.getDecoder().decode(token), keys, now, domainOrAppName, clientType);
         }
         //java byte is signed so we wanna convert to unsigned before checking the enum
         int unsignedByte = ((int) data[1]) & 0xff;
         if (unsignedByte == AdvertisingTokenVersion.V3.value())
         {
-            return decryptV3(Base64.getDecoder().decode(token), keys, now, identityScope, domainName, clientType, 3);
+            return decryptV3(Base64.getDecoder().decode(token), keys, now, identityScope, domainOrAppName, clientType, 3);
         }
         else if (unsignedByte  == AdvertisingTokenVersion.V4.value())
         {
             // Accept either base64 or base64url encoding.
-            return decryptV3(Base64.getDecoder().decode(base64UrlToBase64(token)), keys, now, identityScope, domainName, clientType, 4);
+            return decryptV3(Base64.getDecoder().decode(base64UrlToBase64(token)), keys, now, identityScope, domainOrAppName, clientType, 4);
         }
 
         return DecryptionResponse.makeError(DecryptionStatus.VERSION_NOT_SUPPORTED);
@@ -56,7 +56,7 @@ static String base64UrlToBase64(String value) {
                 .replace('_', '/');
     }
 
-    static DecryptionResponse decryptV2(byte[] encryptedId, KeyContainer keys, Instant now, String domainName, ClientType clientType) throws Exception {
+    static DecryptionResponse decryptV2(byte[] encryptedId, KeyContainer keys, Instant now, String domainOrAppName, ClientType clientType) throws Exception {
         try {
             ByteBuffer rootReader = ByteBuffer.wrap(encryptedId);
             int version = (int) rootReader.get();
@@ -108,6 +108,9 @@ static DecryptionResponse decryptV2(byte[] encryptedId, KeyContainer keys, Insta
             if (now.isAfter(expiry)) {
                 return DecryptionResponse.makeError(DecryptionStatus.EXPIRED_TOKEN, established, siteId, siteKey.getSiteId(), null, advertisingTokenVersion, privacyBits.isClientSideGenerated(), expiry);
             }
+            if (!isDomainOrAppNameAllowedForSite(clientType, privacyBits.isClientSideGenerated(), siteId, domainOrAppName, keys)) {
+                return DecryptionResponse.makeError(DecryptionStatus.DOMAIN_OR_APP_NAME_CHECK_FAILED, established, siteId, siteKey.getSiteId(), null, advertisingTokenVersion, privacyBits.isClientSideGenerated(), expiry);
+            }
 
             if (!doesTokenHaveValidLifetime(clientType, keys, now, expiry, now)) {
                 return DecryptionResponse.makeError(DecryptionStatus.INVALID_TOKEN_LIFETIME, established, siteId, siteKey.getSiteId(), null, advertisingTokenVersion, privacyBits.isClientSideGenerated(), expiry);
@@ -119,7 +122,7 @@ static DecryptionResponse decryptV2(byte[] encryptedId, KeyContainer keys, Insta
         }
     }
 
-    static DecryptionResponse decryptV3(byte[] encryptedId, KeyContainer keys, Instant now, IdentityScope identityScope, String domainName, ClientType clientType, int advertisingTokenVersion) {
+    static DecryptionResponse decryptV3(byte[] encryptedId, KeyContainer keys, Instant now, IdentityScope identityScope, String domainOrAppName, ClientType clientType, int advertisingTokenVersion) {
         try {
             final IdentityType identityType = getIdentityType(encryptedId);
             final ByteBuffer rootReader = ByteBuffer.wrap(encryptedId);
@@ -174,6 +177,9 @@ static DecryptionResponse decryptV3(byte[] encryptedId, KeyContainer keys, Insta
             if (now.isAfter(expiry)) {
                 return DecryptionResponse.makeError(DecryptionStatus.EXPIRED_TOKEN, established, siteId, siteKey.getSiteId(), identityType, advertisingTokenVersion, privacyBits.isClientSideGenerated(), expiry);
             }
+            if (!isDomainOrAppNameAllowedForSite(clientType, privacyBits.isClientSideGenerated(), siteId, domainOrAppName, keys)) {
+                return DecryptionResponse.makeError(DecryptionStatus.DOMAIN_OR_APP_NAME_CHECK_FAILED, established, siteId, siteKey.getSiteId(), identityType, advertisingTokenVersion, privacyBits.isClientSideGenerated(), expiry);
+            }
 
             if (!doesTokenHaveValidLifetime(clientType, keys, generated, expiry, now)) {
                 return DecryptionResponse.makeError(DecryptionStatus.INVALID_TOKEN_LIFETIME, generated, siteId, siteKey.getSiteId(), identityType, advertisingTokenVersion, privacyBits.isClientSideGenerated(), expiry);
@@ -220,7 +226,7 @@ else if (!keys.isValid(now))
     }
 
 
-    static EncryptionDataResponse encryptData(EncryptionDataRequest request, KeyContainer keys, IdentityScope identityScope, String domainName, ClientType clientType) {
+    static EncryptionDataResponse encryptData(EncryptionDataRequest request, KeyContainer keys, IdentityScope identityScope, String domainOrAppName, ClientType clientType) {
         if (request.getData() == null) {
             throw new IllegalArgumentException("data to encrypt must not be null");
         }
@@ -241,7 +247,7 @@ static EncryptionDataResponse encryptData(EncryptionDataRequest request, KeyCont
                 siteKeySiteId = siteId;
             } else {
                 try {
-                    DecryptionResponse decryptedToken = decrypt(request.getAdvertisingToken(), keys, now, identityScope, domainName, clientType);
+                    DecryptionResponse decryptedToken = decrypt(request.getAdvertisingToken(), keys, now, identityScope, domainOrAppName, clientType);
                     if (!decryptedToken.isSuccess()) {
                         return EncryptionDataResponse.makeError(EncryptionStatus.TOKEN_DECRYPT_FAILURE);
                     }
@@ -408,6 +414,16 @@ public CryptoException(Throwable inner) {
         }
     }
 
+    private static boolean isDomainOrAppNameAllowedForSite(ClientType clientType, boolean isClientSideGenerated, Integer siteId, String domainOrAppName, KeyContainer keys) {
+        if (!isClientSideGenerated) {
+            return true;
+        } else if (!clientType.equals(ClientType.BIDSTREAM) && !clientType.equals(ClientType.LEGACY)) {
+            return true;
+        } else {
+            return keys.isDomainOrAppNameAllowedForSite(siteId, domainOrAppName);
+        }
+    }
+
     private static boolean doesTokenHaveValidLifetime(ClientType clientType, KeyContainer keys, Instant generatedOrNow, Instant expiry, Instant now) {
         long maxLifetimeSeconds;
         switch (clientType) {