Add AUtils::isInRange, and use it to detect malformed MPEG4 nal sizes

Bug: 19641538
Change-Id: I5aae3f100846c125decc61eec7cd6563e3f33777

1 files changed, 22 insertions, 0 deletions

diff --git a/include/media/stagefright/foundation/AUtils.h b/include/media/stagefright/foundation/AUtils.h
index 3a73a39..255bcbe 100644
--- a/include/media/stagefright/foundation/AUtils.h
+++ b/include/media/stagefright/foundation/AUtils.h
@@ -55,6 +55,28 @@ inline static const T &max(const T &a, const T &b) {
     return a > b ? a : b;
 }
 
+template<class T>
+void ENSURE_UNSIGNED_TYPE() {
+    T TYPE_MUST_BE_UNSIGNED[(T)-1 < 0 ? -1 : 0] __unused;
+}
+
+// needle is in range [hayStart, hayStart + haySize)
+template<class T, class U>
+inline static bool isInRange(const T &hayStart, const U &haySize, const T &needle) {
+    ENSURE_UNSIGNED_TYPE<U>();
+    return (T)(hayStart + haySize) >= hayStart && needle >= hayStart && (U)(needle - hayStart) < haySize;
+}
+
+// [needleStart, needleStart + needleSize) is in range [hayStart, hayStart + haySize)
+template<class T, class U>
+inline static bool isInRange(
+        const T &hayStart, const U &haySize, const T &needleStart, const U &needleSize) {
+    ENSURE_UNSIGNED_TYPE<U>();
+    return isInRange(hayStart, haySize, needleStart)
+            && (T)(needleStart + needleSize) >= needleStart
+            && (U)(needleStart + needleSize - hayStart) <= haySize;
+}
+
 /* T must be integer type, period must be positive */
 template<class T>
 inline static T periodicError(const T &val, const T &period) {