From 101ef19ef4dc9f5c3d536aee8fcc10fff2af4d9e Mon Sep 17 00:00:00 2001 From: Justin Ruggles Date: Tue, 25 Oct 2011 13:47:50 -0400 Subject: binkaudio: add some buffer overread checks. This stops decoding before overreads instead of after. --- libavcodec/binkaudio.c | 47 +++++++++++++++++++++++++++++++++++++---------- 1 file changed, 37 insertions(+), 10 deletions(-) (limited to 'libavcodec/binkaudio.c') diff --git a/libavcodec/binkaudio.c b/libavcodec/binkaudio.c index 2ed39e9e7a..27e8ff5a84 100644 --- a/libavcodec/binkaudio.c +++ b/libavcodec/binkaudio.c @@ -152,11 +152,18 @@ static const uint8_t rle_length_tab[16] = { 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 32, 64 }; +#define GET_BITS_SAFE(out, nbits) do { \ + if (get_bits_left(gb) < nbits) \ + return AVERROR_INVALIDDATA; \ + out = get_bits(gb, nbits); \ +} while (0) + /** * Decode Bink Audio block * @param[out] out Output buffer (must contain s->block_size elements) + * @return 0 on success, negative error code on failure */ -static void decode_block(BinkAudioContext *s, short *out, int use_dct) +static int decode_block(BinkAudioContext *s, short *out, int use_dct) { int ch, i, j, k; float q, quant[25]; @@ -169,13 +176,19 @@ static void decode_block(BinkAudioContext *s, short *out, int use_dct) for (ch = 0; ch < s->channels; ch++) { FFTSample *coeffs = s->coeffs_ptr[ch]; if (s->version_b) { + if (get_bits_left(gb) < 64) + return AVERROR_INVALIDDATA; coeffs[0] = av_int2flt(get_bits(gb, 32)) * s->root; coeffs[1] = av_int2flt(get_bits(gb, 32)) * s->root; } else { + if (get_bits_left(gb) < 58) + return AVERROR_INVALIDDATA; coeffs[0] = get_float(gb) * s->root; coeffs[1] = get_float(gb) * s->root; } + if (get_bits_left(gb) < s->num_bands * 8) + return AVERROR_INVALIDDATA; for (i = 0; i < s->num_bands; i++) { /* constant is result of 0.066399999/log10(M_E) */ int value = get_bits(gb, 8); @@ -190,15 +203,20 @@ static void decode_block(BinkAudioContext *s, short *out, int use_dct) while (i < s->frame_len) { if (s->version_b) { j = i + 16; - } else if (get_bits1(gb)) { - j = i + rle_length_tab[get_bits(gb, 4)] * 8; } else { - j = i + 8; + int v; + GET_BITS_SAFE(v, 1); + if (v) { + GET_BITS_SAFE(v, 4); + j = i + rle_length_tab[v] * 8; + } else { + j = i + 8; + } } j = FFMIN(j, s->frame_len); - width = get_bits(gb, 4); + GET_BITS_SAFE(width, 4); if (width == 0) { memset(coeffs + i, 0, (j - i) * sizeof(*coeffs)); i = j; @@ -208,9 +226,11 @@ static void decode_block(BinkAudioContext *s, short *out, int use_dct) while (i < j) { if (s->bands[k] == i) q = quant[k++]; - coeff = get_bits(gb, width); + GET_BITS_SAFE(coeff, width); if (coeff) { - if (get_bits1(gb)) + int v; + GET_BITS_SAFE(v, 1); + if (v) coeffs[i] = -q * coeff; else coeffs[i] = q * coeff; @@ -246,6 +266,8 @@ static void decode_block(BinkAudioContext *s, short *out, int use_dct) s->overlap_len * s->channels * sizeof(*out)); s->first = 0; + + return 0; } static av_cold int decode_end(AVCodecContext *avctx) @@ -277,12 +299,17 @@ static int decode_frame(AVCodecContext *avctx, int reported_size; GetBitContext *gb = &s->gb; + if (buf_size < 4) { + av_log(avctx, AV_LOG_ERROR, "Packet is too small\n"); + return AVERROR_INVALIDDATA; + } + init_get_bits(gb, buf, buf_size * 8); reported_size = get_bits_long(gb, 32); - while (get_bits_count(gb) / 8 < buf_size && - samples + s->block_size <= samples_end) { - decode_block(s, samples, avctx->codec->id == CODEC_ID_BINKAUDIO_DCT); + while (samples + s->block_size <= samples_end) { + if (decode_block(s, samples, avctx->codec->id == CODEC_ID_BINKAUDIO_DCT)) + break; samples += s->block_size; get_bits_align32(gb); } -- cgit v1.2.3