mpegts: prevent get_bits64() from reading nonsense at the end.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 3 insertions, 0 deletions

diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
index 3d825fe193..e6c353df0e 100644
--- a/libavformat/mpegts.c
+++ b/libavformat/mpegts.c
@@ -693,6 +693,9 @@ static void new_pes_packet(PESContext *pes, AVPacket *pkt)
 static uint64_t get_bits64(GetBitContext *gb, int bits)
 {
     uint64_t ret = 0;
+
+    if (get_bits_left(gb) < bits)
+        return AV_NOPTS_VALUE;
     while (bits > 17) {
         ret <<= 17;
         ret |= get_bits(gb, 17);