1 files changed, 12 insertions, 7 deletions
diff --git a/objectivec/GPBCodedInputStream.m b/objectivec/GPBCodedInputStream.m
index e8c8989c..22859e77 100644
--- a/objectivec/GPBCodedInputStream.m
+++ b/objectivec/GPBCodedInputStream.m
@@ -45,7 +45,12 @@ NSString *const GPBCodedInputStreamUnderlyingErrorKey =
 NSString *const GPBCodedInputStreamErrorDomain =
     GPBNSStringifySymbol(GPBCodedInputStreamErrorDomain);
 
-static const NSUInteger kDefaultRecursionLimit = 64;
+// Matching:
+// https://github.com/google/protobuf/blob/master/java/core/src/main/java/com/google/protobuf/CodedInputStream.java#L62
+//  private static final int DEFAULT_RECURSION_LIMIT = 100;
+// https://github.com/google/protobuf/blob/master/src/google/protobuf/io/coded_stream.cc#L86
+//  int CodedInputStream::default_recursion_limit_ = 100;
+static const NSUInteger kDefaultRecursionLimit = 100;
 
 static void RaiseException(NSInteger code, NSString *reason) {
   NSDictionary *errorInfo = nil;
@@ -225,16 +230,16 @@ int32_t GPBCodedInputStreamReadTag(GPBCodedInputStreamState *state) {
   }
 
   state->lastTag = ReadRawVarint32(state);
-  if (state->lastTag == 0) {
-    // If we actually read zero, that's not a valid tag.
-    RaiseException(GPBCodedInputStreamErrorInvalidTag,
-                   @"A zero tag on the wire is invalid.");
-  }
-  // Tags have to include a valid wireformat, check that also.
+  // Tags have to include a valid wireformat.
   if (!GPBWireFormatIsValidTag(state->lastTag)) {
     RaiseException(GPBCodedInputStreamErrorInvalidTag,
                    @"Invalid wireformat in tag.");
   }
+  // Zero is not a valid field number.
+  if (GPBWireFormatGetTagFieldNumber(state->lastTag) == 0) {
+    RaiseException(GPBCodedInputStreamErrorInvalidTag,
+                   @"A zero field number on the wire is invalid.");
+  }
   return state->lastTag;
 }