From: Francois Cartegnie <fcvlcdev@free.fr>
Date: Mon, 23 Mar 2015 22:38:12 +0000 (+0100)
Subject: demux: avi: improve broken index offset heuristic (fix #14120)
X-Git-Url: https://git.sesse.net/?p=vlc;a=commitdiff_plain;h=039c69d648bd9bb481fbd29868b8565952098d70

demux: avi: improve broken index offset heuristic (fix #14120)

Avoids using movi position as offset when the broken index refers
to beginning of file and the first sample size is exactly movi's
offset.
---

diff --git a/modules/demux/avi/avi.c b/modules/demux/avi/avi.c
index 0a35b42269..34a3362181 100644
--- a/modules/demux/avi/avi.c
+++ b/modules/demux/avi/avi.c
@@ -2321,11 +2321,22 @@ static int AVI_IndexFind_idx1( demux_t *p_demux,
             *pi_offset = 0;
         else
             *pi_offset = i_movi_content;
+
+        if( p_idx1->i_entry_count )
+        {
+            /* Invalidate offset if index refers past the data section to avoid false
+               positives when the offset equals sample size */
+            size_t i_dataend = *pi_offset + p_idx1->entry[p_idx1->i_entry_count - 1].i_pos +
+                                            p_idx1->entry[p_idx1->i_entry_count - 1].i_length;
+            if( i_dataend > p_movi->i_chunk_pos + p_movi->i_chunk_size )
+                *pi_offset = 0;
+        }
     }
     else
     {
         *pi_offset = 0;
     }
+
     return VLC_SUCCESS;
 }