[vlc-devel] [PATCH] DASH: prevent integer overflow

[fyhuel at viotech.net]

From: Frédéric Yhuel <fyhuel at viotech.net>

A integer overflow could happen in bandwidth computation, for example if
we have a DASH server and client on the same machine.
---
 .../dash/http/HTTPConnectionManager.cpp            |   20 ++++++++++++++++----
 1 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/modules/stream_filter/dash/http/HTTPConnectionManager.cpp b/modules/stream_filter/dash/http/HTTPConnectionManager.cpp
index 1a5e7d0..7ebc4ad 100644
--- a/modules/stream_filter/dash/http/HTTPConnectionManager.cpp
+++ b/modules/stream_filter/dash/http/HTTPConnectionManager.cpp
@@ -107,12 +107,24 @@ int                 HTTPConnectionManager::read( Chunk *chunk, void *p_buffer, s
         this->timeSecSession   += time;
         this->timeSecChunk     += time;
 
-
+        unsigned long long bytepsAvg;
         if(this->timeSecSession > 0)
-            this->bpsAvg = (this->bytesReadSession / this->timeSecSession) * 8;
-
+        {
+            /* Integer overflow may happen */
+            bytepsAvg = this->bytesReadSession / this->timeSecSession;
+            if(bytepsAvg > (LONG_MAX / 8))
+                this->bpsAvg = LONG_MAX;
+            else
+                this->bpsAvg = bytepsAvg * 8;
+        }
         if(this->timeSecChunk > 0)
-            this->bpsLastChunk = (this->bytesReadChunk / this->timeSecChunk) * 8;
+        {
+            bytepsAvg = this->bytesReadChunk / this->timeSecChunk;
+            if(bytepsAvg > (INT_MAX / 8))
+                this->bpsAvg = INT_MAX;
+            else
+                this->bpsAvg = bytepsAvg * 8;
+        }
 
         if(this->bpsAvg < 0 || this->chunkCount < 2)
             this->bpsAvg = 0;
-- 
1.7.5.4