From 2b09f9b53a149416e617360d2d8c77c7ffc8e9cf Mon Sep 17 00:00:00 2001
From: David Schalig <dschalig@nvidia.com>
Date: Wed, 28 Nov 2012 12:18:32 +0900
Subject: [PATCH] mkvparser: ignore 0-size elements in TrackEntry

ParseTrackEntry handled MKVs with 0-sized EBML elements
as malformed. Relaxing this and allow empty elements to allow
parsing such MKV content.

Change-Id: I7e430e9b2d177df7fe1e656546f63ee8673e784e
---
 mkvparser.cpp | 50 ++++++++++++++++++++++----------------------------
 1 file changed, 22 insertions(+), 28 deletions(-)

diff --git a/mkvparser.cpp b/mkvparser.cpp
index 43eb099..da12756 100644
--- a/mkvparser.cpp
+++ b/mkvparser.cpp
@@ -6533,35 +6533,29 @@ long Tracks::ParseTrackEntry(
         if (status < 0)  //error
             return status;
 
+        if (size < 0)
+            return E_FILE_FORMAT_INVALID;
+
         const long long start = pos;
 
         if (id == 0x60)  // VideoSettings ID
         {
-            if (size <= 0)
-                return E_FILE_FORMAT_INVALID;
-
             v.start = start;
             v.size = size;
         }
         else if (id == 0x61)  // AudioSettings ID
         {
-            if (size <= 0)
-                return E_FILE_FORMAT_INVALID;
-
             a.start = start;
             a.size = size;
         }
         else if (id == 0x2D80) // ContentEncodings ID
         {
-            if (size <= 0)
-                return E_FILE_FORMAT_INVALID;
-
             e.start = start;
             e.size = size;
         }
         else if (id == 0x33C5)  //Track UID
         {
-            if ((size <= 0) || (size > 8))
+            if (size > 8)
                 return E_FILE_FORMAT_INVALID;
 
             info.uid = 0;
@@ -6637,28 +6631,28 @@ long Tracks::ParseTrackEntry(
             info.codecPrivate = NULL;
             info.codecPrivateSize = 0;
 
-            if (size <= 0)
-                return E_FILE_FORMAT_INVALID;
-
             const size_t buflen = static_cast<size_t>(size);
 
-            typedef unsigned char* buf_t;
-
-            const buf_t buf = new (std::nothrow) unsigned char[buflen];
-
-            if (buf == NULL)
-                return -1;
-
-            const int status = pReader->Read(pos, buflen, buf);
-
-            if (status)
+            if (buflen)
             {
-                delete[] buf;
-                return status;
-            }
+                typedef unsigned char* buf_t;
 
-            info.codecPrivate = buf;
-            info.codecPrivateSize = buflen;
+                const buf_t buf = new (std::nothrow) unsigned char[buflen];
+
+                if (buf == NULL)
+                    return -1;
+
+                const int status = pReader->Read(pos, buflen, buf);
+
+                if (status)
+                {
+                    delete[] buf;
+                    return status;
+                }
+
+                info.codecPrivate = buf;
+                info.codecPrivateSize = buflen;
+            }
         }
         else if (id == 0x058688)  //Codec Name
         {