Fix invalid reads in VC1 decoder

Patch discussed and taken from https://roundup.ffmpeg.org/issue2584 (cherry picked from commit 2bbec1eda4)
14 years ago · c614d32e22
parent 0cfcbf217f
commit c614d32e22
1 changed files with 1 additions and 1 deletions
--- a/libavcodec/vc1dec.c
+++ b/libavcodec/vc1dec.c
@ -1376,7 +1376,7 @@ static void vc1_decode_ac_coeff(VC1Context *v, int *last, int *skip, int *value,
    if (index != vc1_ac_sizes[codingset] - 1) {
        run = vc1_index_decode_table[codingset][index][0];
        level = vc1_index_decode_table[codingset][index][1];
-        lst = index >= vc1_last_decode_table[codingset];
+        lst = index >= vc1_last_decode_table[codingset] || get_bits_left(gb) < 0;
        if(get_bits1(gb))
            level = -level;
    } else {