grpc: limit reader with maxReceiveMessageSize (#2617)

menghanl · web-flow · commit 01e57758bcc8 · 2019-02-07T13:32:00.000-08:00
fixes #2616
diff --git a/rpc_util.go b/rpc_util.go
@@ -661,7 +661,9 @@ func recvAndDecompress(p *parser, s *transport.Stream, dc Decompressor, maxRecei
 			if err != nil {
 				return nil, status.Errorf(codes.Internal, "grpc: failed to decompress the received message %v", err)
 			}
-			d, err = ioutil.ReadAll(dcReader)
+			// Read from LimitReader with limit max+1. So if the underlying
+			// reader is over limit, the result will be bigger than max.
+			d, err = ioutil.ReadAll(io.LimitReader(dcReader, int64(maxReceiveMessageSize)+1))
 			if err != nil {
 				return nil, status.Errorf(codes.Internal, "grpc: failed to decompress the received message %v", err)
 			}

Original file line number	Diff line number	Diff line change
`@@ -661,7 +661,9 @@ func recvAndDecompress(p parser, s transport.Stream, dc Decompressor, maxRecei`
`661`	`661`	`if err != nil {`
`662`	`662`	`return nil, status.Errorf(codes.Internal, "grpc: failed to decompress the received message %v", err)`
`663`	`663`	`}`
`664`		`- d, err = ioutil.ReadAll(dcReader)`
	`664`	`+ // Read from LimitReader with limit max+1. So if the underlying`
	`665`	`+ // reader is over limit, the result will be bigger than max.`
	`666`	`+ d, err = ioutil.ReadAll(io.LimitReader(dcReader, int64(maxReceiveMessageSize)+1))`
`665`	`667`	`if err != nil {`
`666`	`668`	`return nil, status.Errorf(codes.Internal, "grpc: failed to decompress the received message %v", err)`
`667`	`669`	`}`