fread.diff

diff --git a/pintraces/pin_taint.cpp b/pintraces/pin_taint.cpp
index 659ddc1..3a69392 100644
--- a/pintraces/pin_taint.cpp
+++ b/pintraces/pin_taint.cpp
@@ -218,6 +218,21 @@ context TaintTracker::getMemory()
 FrameOption_t TaintTracker::introMemTaint(uint32_t addr, uint32_t length, const char *source, int64_t offset) {
 
   FrameOption_t fb;
+  uint32_t buffer_size;
+  uint8_t value;
+
+  //Length can be bigger than the buffer size, so take a minimum of these 
+  //two values.
+  buffer_size = 0;
+  for (unsigned int i = 0; i < length; i++) {
+    if(PIN_SafeCopy((void*) &value, (void*) (addr+i), 1) != 1){
+      break;
+    }
+    buffer_size++;
+  }
+  cerr << "buffer_size: " << buffer_size << ", requested length: " << length <<
+    endl;
+  length = min(length, buffer_size);
 
   if ((*pf)(addr, length, source) && length > 0) {
 
@@ -250,7 +265,6 @@ FrameOption_t TaintTracker::introMemTaint(uint32_t addr, uint32_t length, const
         off += i;
       }
       tfi->set_offset(off);
-      uint8_t value;
       assert (PIN_SafeCopy((void*) &value, (void*) (addr+i), 1) == 1);
       tfi->set_value((void*) &value, 1);
     }