From c4a90caae249a8bafb7534bac41f7ae89229a672 Mon Sep 17 00:00:00 2001 From: Alex Converse Date: Wed, 24 Feb 2010 23:56:52 +0000 Subject: [PATCH] aac: Keep decode_band_types() from eating all padding at the end of a buffer. Due to a shortcoming in the AAC specification, if an all zero buffer is fed to section data decoding it will never terminate. That means without a buffer exhaustion check decode_band_types() will consume all input buffer padding. Worse if a get_bits() implementation that returns zeros when padding is exhausted is used, the function will never terminate. The fixes that by added a buffer exhaustion check in the sectioning decoding loop. Originally committed as revision 22044 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/aac.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/libavcodec/aac.c b/libavcodec/aac.c index 87eac4c74a..faf1d7287f 100644 --- a/libavcodec/aac.c +++ b/libavcodec/aac.c @@ -715,6 +715,10 @@ static int decode_band_types(AACContext *ac, enum BandType band_type[120], while ((sect_len_incr = get_bits(gb, bits)) == (1 << bits) - 1) sect_end += sect_len_incr; sect_end += sect_len_incr; + if (get_bits_left(gb) < 0) { + av_log(ac->avccontext, AV_LOG_ERROR, overread_err); + return -1; + } if (sect_end > ics->max_sfb) { av_log(ac->avccontext, AV_LOG_ERROR, "Number of bands (%d) exceeds limit (%d).\n",