Support malformed resource names/namespaces by falling back to resId (#2886)

* Correct falsely-referenced attribute into an entity which is an obfuscated name

* style: correct syntax for custom attributes

* fix: remove unused import

Co-authored-by: MyAnoneNeko <MyAnoneNeko@users.noreply.github.com>

brut.apktool/apktool-lib/src/main/java/brut/androlib/res/decoder/AXmlResourceParser.java

@@ -336,16 +336,26 @@ public class AXmlResourceParser implements XmlResourceParser {
         }
 
         String value = m_strings.getString(name);
+        String namespace = getAttributeNamespace(index);
 
-        // some attributes will return "", we must rely on the resource_id and refer to the frameworks
+        // If attribute name is lacking or a private namespace emerges,
-        // to match the resource id to the name. ex: 0x101021C = versionName
+        // retrieve the exact attribute name by its id.
-        if (value.length() == 0 || android_ns.equals(getAttributeNamespace(index))) {
+        if (value == null || value.length() == 0) {
             try {
-                int resourceId = getAttributeNameResource(index);
-                if (resourceId != 0) {
                 value = mAttrDecoder.decodeManifestAttr(getAttributeNameResource(index));
+                if (value == null) {
+                    value = "";
                 }
-            } catch (AndrolibException | NullPointerException ignored) {}
+            } catch (AndrolibException e) {
+                value = "";
+            }
+        } else if (! namespace.equals(android_ns)) {
+            try {
+                String obfuscatedName = mAttrDecoder.decodeManifestAttr(getAttributeNameResource(index));
+                if (! (obfuscatedName == null || obfuscatedName.equals(value))) {
+                    value = obfuscatedName;
+                }
+            } catch (AndrolibException ignored) {}
         }
         return value;
     }
@@ -381,11 +391,27 @@ public class AXmlResourceParser implements XmlResourceParser {
 
         if (mAttrDecoder != null) {
             try {
+                String value = valueRaw == -1 ? null : ResXmlEncoders.escapeXmlChars(m_strings.getString(valueRaw));
+                String obfuscatedValue = mAttrDecoder.decodeManifestAttr(valueData);
+
+                if (! (value == null || obfuscatedValue == null)) {
+                    int slashPos = value.lastIndexOf("/");
+
+                    if (slashPos != -1) {
+                        // Handle a value with a format of "@yyy/xxx"
+                        String dir = value.substring(0, slashPos);
+                        value = dir + "/"+ obfuscatedValue;
+                    } else if (! value.equals(obfuscatedValue)) {
+                        value = obfuscatedValue;
+                    }
+                }
+
                 return mAttrDecoder.decode(
                     valueType,
                     valueData,
-                        valueRaw == -1 ? null : ResXmlEncoders.escapeXmlChars(m_strings.getString(valueRaw)),
+                    value,
-                        getAttributeNameResource(index));
+                    getAttributeNameResource(index)
+                );
             } catch (AndrolibException ex) {
                 setFirstError(ex);
                 LOGGER.log(Level.WARNING, String.format("Could not decode attr value, using undecoded value "

brut.apktool/apktool-lib/src/main/java/brut/androlib/res/decoder/ResAttrDecoder.java

@@ -18,6 +18,7 @@ package brut.androlib.res.decoder;
 
 import brut.androlib.AndrolibException;
 import brut.androlib.err.UndefinedResObjectException;
+import brut.androlib.res.data.ResID;
 import brut.androlib.res.data.ResPackage;
 import brut.androlib.res.data.ResResSpec;
 import brut.androlib.res.data.value.ResAttr;
@@ -48,12 +49,26 @@ public class ResAttrDecoder {
         throws AndrolibException {
 
         if (attrResId != 0) {
-            ResResSpec resResSpec = getCurrentPackage().getResTable().getResSpec(attrResId);
+            int attrId = attrResId;
 
+            // See also: brut.androlib.res.data.ResTable.getResSpec
+            if (attrId >> 24 == 0) {
+                ResPackage pkg = getCurrentPackage();
+                int packageId = pkg.getId();
+                int pkgId = (packageId == 0 ? 2 : packageId);
+                attrId = (0xFF000000 & (pkgId << 24)) | attrId;
+            }
+
+            // Retrieve the ResSpec in a package by id
+            ResID resId = new ResID(attrId);
+            ResPackage pkg = getCurrentPackage();
+            if (pkg.hasResSpec(resId)) {
+                ResResSpec resResSpec = pkg.getResSpec(resId);
                 if (resResSpec != null) {
                     return resResSpec.getName();
                 }
             }
+        }
 
         return null;
     }