protobuf-lite: ProtoLiteUtils fix infinite loop

InputStream by contract can return zero if requested length equal to zero.

```
If len is zero, then no bytes are read and 0 is returned;
otherwise, there is an attempt to read at least one byte.
If no byte is available because the stream is at end of file,
the value -1 is returned; otherwise, at least one byte is read
and stored into b.
```

Close #3323

1 files changed, 12 insertions, 5 deletions

diff --git a/protobuf-lite/src/main/java/io/grpc/protobuf/lite/ProtoLiteUtils.java b/protobuf-lite/src/main/java/io/grpc/protobuf/lite/ProtoLiteUtils.java
index 891420134..2a88a3f89 100644
--- a/protobuf-lite/src/main/java/io/grpc/protobuf/lite/ProtoLiteUtils.java
+++ b/protobuf-lite/src/main/java/io/grpc/protobuf/lite/ProtoLiteUtils.java
@@ -128,12 +128,19 @@ public class ProtoLiteUtils {
                 buf = new byte[size];
                 bufs.set(new WeakReference<byte[]>(buf));
               }
-              int chunkSize;
-              int position = 0;
-              while ((chunkSize = stream.read(buf, position, size - position)) != -1) {
-                position += chunkSize;
+
+              int remaining = size;
+              while (remaining > 0) {
+                int position = size - remaining;
+                int count = stream.read(buf, position, remaining);
+                if (count == -1) {
+                  break;
+                }
+                remaining -= count;
               }
-              if (size != position) {
+
+              if (remaining != 0) {
+                int position = size - remaining;
                 throw new RuntimeException("size inaccurate: " + size + " != " + position);
               }
               cis = CodedInputStream.newInstance(buf, 0, size);