From 349b7977e408f18cff01ab31dfa66c8249b6584a Mon Sep 17 00:00:00 2001 From: "Ronald S. Bultje" Date: Thu, 1 Mar 2012 16:19:51 -0800 Subject: wma: fix invalid buffer size assumptions causing random overreads. Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind CC: libav-stable@libav.org --- libavcodec/wmadec.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'libavcodec/wmadec.c') diff --git a/libavcodec/wmadec.c b/libavcodec/wmadec.c index b9fc21fd3e..37feca1f7f 100644 --- a/libavcodec/wmadec.c +++ b/libavcodec/wmadec.c @@ -845,6 +845,12 @@ static int wma_decode_superframe(AVCodecContext *avctx, void *data, if (s->use_bit_reservoir) { bit_offset = get_bits(&s->gb, s->byte_offset_bits + 3); + if (bit_offset > get_bits_left(&s->gb)) { + av_log(avctx, AV_LOG_ERROR, + "Invalid last frame bit offset %d > buf size %d (%d)\n", + bit_offset, get_bits_left(&s->gb), buf_size); + goto fail; + } if (s->last_superframe_len > 0) { // printf("skip=%d\n", s->last_bitoffset); @@ -861,9 +867,10 @@ static int wma_decode_superframe(AVCodecContext *avctx, void *data, if (len > 0) { *q++ = (get_bits)(&s->gb, len) << (8 - len); } + memset(q, 0, FF_INPUT_BUFFER_PADDING_SIZE); /* XXX: bit_offset bits into last frame */ - init_get_bits(&s->gb, s->last_superframe, MAX_CODED_SUPERFRAME_SIZE*8); + init_get_bits(&s->gb, s->last_superframe, s->last_superframe_len * 8 + bit_offset); /* skip unused bits */ if (s->last_bitoffset > 0) skip_bits(&s->gb, s->last_bitoffset); @@ -877,9 +884,9 @@ static int wma_decode_superframe(AVCodecContext *avctx, void *data, /* read each frame starting from bit_offset */ pos = bit_offset + 4 + 4 + s->byte_offset_bits + 3; - if (pos >= MAX_CODED_SUPERFRAME_SIZE * 8) + if (pos >= MAX_CODED_SUPERFRAME_SIZE * 8 || pos > buf_size * 8) return AVERROR_INVALIDDATA; - init_get_bits(&s->gb, buf + (pos >> 3), (MAX_CODED_SUPERFRAME_SIZE - (pos >> 3))*8); + init_get_bits(&s->gb, buf + (pos >> 3), (buf_size - (pos >> 3))*8); len = pos & 7; if (len > 0) skip_bits(&s->gb, len); -- cgit v1.2.3