commit 66b2b04145b1d1007f03356e0106b16ad5e8fa46
author Steven Moreland <smoreland@google.com> Wed Jun 05 10:25:28 2019 -0700
committer android-build-merger <android-build-merger@google.com> Wed Jun 05 10:25:28 2019 -0700
tree 316be3046ef79fe466eb0522d82406f1476d78dd
parent a8f3b389b0a167823585e6033487478ec199527e
parent 1ab3b13ae5dfc07f1311a07d09e654b1cfc9c012

readCString: no ubsan sub-overflow am: 1086548c6c am: 13788cbc36 am: 1a4c63ee1a am: 87a7f9eb07
am: 1ab3b13ae5

Change-Id: Ia832d4278ff81859a48d3ceadd93642e5249e4cb

Parcel.cpp

diff --git a/Parcel.cpp b/Parcel.cpp
index 4b61738..d6ea481 100644
--- a/Parcel.cpp
+++ b/Parcel.cpp
@@ -1324,8 +1324,8 @@
 
 const char* Parcel::readCString() const
 {
-    const size_t avail = mDataSize-mDataPos;
-    if (avail > 0) {
+    if (mDataPos < mDataSize) {
+        const size_t avail = mDataSize-mDataPos;
         const char* str = reinterpret_cast<const char*>(mData+mDataPos);
         // is the string's trailing NUL within the parcel's valid bounds?
         const char* eos = reinterpret_cast<const char*>(memchr(str, 0, avail));