diff --git a/media/libstagefright/MPEG4Extractor.cpp b/media/libstagefright/MPEG4Extractor.cpp
index 193e51b..bbd351a 100644
--- a/media/libstagefright/MPEG4Extractor.cpp
+++ b/media/libstagefright/MPEG4Extractor.cpp
@@ -4098,6 +4098,14 @@
 
     if ((!mIsAVC && !mIsHEVC)|| mWantsNALFragments) {
         if (newBuffer) {
+            if (!isInRange((size_t)0u, mBuffer->size(), size)) {
+                mBuffer->release();
+                mBuffer = NULL;
+
+                ALOGE("fragmentedRead ERROR_MALFORMED size %zu", size);
+                return ERROR_MALFORMED;
+            }
+
             ssize_t num_bytes_read =
                 mDataSource->readAt(offset, (uint8_t *)mBuffer->data(), size);
 
@@ -4105,7 +4113,7 @@
                 mBuffer->release();
                 mBuffer = NULL;
 
-                ALOGV("i/o error");
+                ALOGE("i/o error");
                 return ERROR_IO;
             }
 
@@ -4177,18 +4185,40 @@
         ssize_t num_bytes_read = 0;
         int32_t drm = 0;
         bool usesDRM = (mFormat->findInt32(kKeyIsDRM, &drm) && drm != 0);
+        void *data = NULL;
+        bool isMalFormed = false;
         if (usesDRM) {
-            num_bytes_read =
-                mDataSource->readAt(offset, (uint8_t*)mBuffer->data(), size);
+            if (mBuffer == NULL || !isInRange((size_t)0u, mBuffer->size(), size)) {
+                isMalFormed = true;
+            } else {
+                data = mBuffer->data();
+            }
         } else {
-            num_bytes_read = mDataSource->readAt(offset, mSrcBuffer, size);
+            int32_t max_size;
+            if (mFormat == NULL
+                    || !mFormat->findInt32(kKeyMaxInputSize, &max_size)
+                    || !isInRange((size_t)0u, (size_t)max_size, size)) {
+                isMalFormed = true;
+            } else {
+                data = mSrcBuffer;
+            }
         }
 
+        if (isMalFormed || data == NULL) {
+            ALOGE("isMalFormed size %zu", size);
+            if (mBuffer != NULL) {
+                mBuffer->release();
+                mBuffer = NULL;
+            }
+            return ERROR_MALFORMED;
+        }
+        num_bytes_read = mDataSource->readAt(offset, data, size);
+
         if (num_bytes_read < (ssize_t)size) {
             mBuffer->release();
             mBuffer = NULL;
 
-            ALOGV("i/o error");
+            ALOGE("i/o error");
             return ERROR_IO;
         }
 
@@ -4202,16 +4232,18 @@
             size_t dstOffset = 0;
 
             while (srcOffset < size) {
-                bool isMalFormed = !isInRange((size_t)0u, size, srcOffset, mNALLengthSize);
+                isMalFormed = !isInRange((size_t)0u, size, srcOffset, mNALLengthSize);
                 size_t nalLength = 0;
                 if (!isMalFormed) {
                     nalLength = parseNALSize(&mSrcBuffer[srcOffset]);
                     srcOffset += mNALLengthSize;
-                    isMalFormed = !isInRange((size_t)0u, size, srcOffset, nalLength);
+                    isMalFormed = !isInRange((size_t)0u, size, srcOffset, nalLength)
+                            || !isInRange((size_t)0u, mBuffer->size(), dstOffset, (size_t)4u)
+                            || !isInRange((size_t)0u, mBuffer->size(), dstOffset + 4, nalLength);
                 }
 
                 if (isMalFormed) {
-                    ALOGE("Video is malformed");
+                    ALOGE("Video is malformed; nalLength %zu", nalLength);
                     mBuffer->release();
                     mBuffer = NULL;
                     return ERROR_MALFORMED;