[vlc-devel] [PATCH 6/7] demux:mkv: don't read further than our parent or its parent
Steve Lhomme
robux4 at videolabs.io
Mon Nov 13 18:08:45 CET 2017
---
modules/demux/mkv/Ebml_parser.cpp | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/modules/demux/mkv/Ebml_parser.cpp b/modules/demux/mkv/Ebml_parser.cpp
index 330edd4c7c..5f663c6a45 100644
--- a/modules/demux/mkv/Ebml_parser.cpp
+++ b/modules/demux/mkv/Ebml_parser.cpp
@@ -158,6 +158,27 @@ EbmlElement *EbmlParser::Get( int n_call )
if( p_prev )
p_prev->SkipData( *m_es, EBML_CONTEXT(p_prev) );
+ uint64_t i_max_read;
+ if (mi_level == 0)
+ i_max_read = UINT64_MAX;
+ else if (!m_el[mi_level-1]->IsFiniteSize())
+ i_max_read = UINT64_MAX;
+ else if (!p_prev)
+ i_max_read = m_el[mi_level-1]->GetSize();
+ else {
+ size_t size_lvl = mi_level;
+ while ( size_lvl && m_el[size_lvl-1]->IsFiniteSize() &&
+ m_el[size_lvl-1]->GetEndPosition() == m_el[size_lvl]->GetEndPosition() )
+ size_lvl--;
+ if (size_lvl == 0 || !m_el[size_lvl-1]->IsFiniteSize() )
+ i_max_read = UINT64_MAX;
+ else {
+ uint64 top = m_el[size_lvl-1]->GetEndPosition();
+ uint64 bom = m_el[mi_level]->GetEndPosition();
+ i_max_read = top - bom;
+ }
+ }
+
// If the parent is a segment, use the segment context when creating children
// (to prolong their lifetime), otherwise just continue as normal
EbmlSemanticContext e_context =
@@ -167,7 +188,7 @@ EbmlElement *EbmlParser::Get( int n_call )
/* Ignore unknown level 0 or 1 elements */
m_el[mi_level] = m_es->FindNextElement( e_context,
- i_ulev, UINT64_MAX,
+ i_ulev, i_max_read,
( mb_dummy | (mi_level > 1) ), 1 );
if( i_ulev > 0 )
{
--
2.14.2
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