Fixes an out-of-bounds read issue with the padding handling code

This was reported by Juri Aedla and is limited to reading memory up
to about 60 kB beyond the compressed buffer. This can only be triggered
by a compressed packet more than about 16 MB long, so it's not a problem
for RTP. In theory, it *could* crash an Ogg decoder if the memory just after
the incoming packet is out-of-range.

1 files changed, 1 insertions, 3 deletions

diff --git a/src/opus_decoder.c b/src/opus_decoder.c
index 167e4e48..0be6730d 100644
--- a/src/opus_decoder.c
+++ b/src/opus_decoder.c
@@ -641,16 +641,14 @@ static int opus_packet_parse_impl(const unsigned char *data, opus_int32 len,
       /* Padding flag is bit 6 */
       if (ch&0x40)
       {
-         int padding=0;
          int p;
          do {
             if (len<=0)
                return OPUS_INVALID_PACKET;
             p = *data++;
             len--;
-            padding += p==255 ? 254: p;
+            len -= p==255 ? 254: p;
          } while (p==255);
-         len -= padding;
       }
       if (len<0)
          return OPUS_INVALID_PACKET;