am 5b85b1d4: libutils: fix overflow in String8::allocFromUTF8

* commit '5b85b1d40d619c2064d321364f212ebfeb6ba185':
  libutils: fix overflow in String8::allocFromUTF8
diff --git a/libutils/String8.cpp b/libutils/String8.cpp
index e852d77..e5a48e5 100644
--- a/libutils/String8.cpp
+++ b/libutils/String8.cpp
@@ -78,6 +78,9 @@
 static char* allocFromUTF8(const char* in, size_t len)
 {
     if (len > 0) {
+        if (len == SIZE_MAX) {
+            return NULL;
+        }
         SharedBuffer* buf = SharedBuffer::alloc(len+1);
         ALOG_ASSERT(buf, "Unable to allocate shared buffer");
         if (buf) {