From: Marcus Holland-Moritz <mhx@fb.com>
Date: Tue, 17 May 2016 20:08:17 +0000 (-0700)
Subject: folly: fbvector: ubsan: don't call memcpy() with nullptr args if size == 0
X-Git-Tag: 2016.07.26~228
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=1072a897f5c17f2d13de16450059baa81c61d525;p=folly.git

folly: fbvector: ubsan: don't call memcpy() with nullptr args if size == 0

Reviewed By: meyering, luciang

Differential Revision: D3310683

fbshipit-source-id: c86471d54062b2f3455f15fb73340fac486d9e44
---

diff --git a/folly/FBVector.h b/folly/FBVector.h
index fb611e56..036882a4 100644
--- a/folly/FBVector.h
+++ b/folly/FBVector.h
@@ -522,7 +522,9 @@ private:
 
   static void
   S_uninitialized_copy_bits(T* dest, const T* first, const T* last) {
-    std::memcpy((void*)dest, (void*)first, (last - first) * sizeof(T));
+    if (last != first) {
+      std::memcpy((void*)dest, (void*)first, (last - first) * sizeof(T));
+    }
   }
 
   static void
@@ -530,7 +532,9 @@ private:
                        std::move_iterator<T*> last) {
     T* bFirst = first.base();
     T* bLast = last.base();
-    std::memcpy((void*)dest, (void*)bFirst, (bLast - bFirst) * sizeof(T));
+    if (bLast != bFirst) {
+      std::memcpy((void*)dest, (void*)bFirst, (bLast - bFirst) * sizeof(T));
+    }
   }
 
   template <typename It>