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vorbis: An additional defense in the Vorbis codec.

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BUG=101458
Review URL: http://codereview.chromium.org/8414025

Fixes second part of CVE-2011-3895

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Chris Evans 2012-01-04 21:53:35 +01:00 committed by Michael Niedermayer
parent 68226ed9ec
commit f74ce3a60d
1 changed files with 25 additions and 10 deletions
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35
libavcodec/vorbisdec.c
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@ -1286,6 +1286,7 @@ static av_always_inline int vorbis_residue_decode_internal(vorbis_context *vc,
uint8_t *do_not_decode,
float *vec,
unsigned vlen,
unsigned ch_left,
int vr_type)
{
GetBitContext *gb = &vc->gb;
@ -1293,6 +1294,7 @@ static av_always_inline int vorbis_residue_decode_internal(vorbis_context *vc,
unsigned ptns_to_read = vr->ptns_to_read;
uint8_t *classifs = vr->classifs;
unsigned pass, ch_used, i, j, k, l;
unsigned max_output = (ch - 1) * vlen;
if (vr_type == 2) {
for (j = 1; j < ch; ++j)
@ -1300,8 +1302,15 @@ static av_always_inline int vorbis_residue_decode_internal(vorbis_context *vc,
if (do_not_decode[0])
return 0;
ch_used = 1;
max_output += vr->end / ch;
} else {
ch_used = ch;
max_output += vr->end;
}
if (max_output > ch_left * vlen) {
av_log(vc->avccontext, AV_LOG_ERROR, "Insufficient output buffer\n");
return -1;
}
av_dlog(NULL, " residue type 0/1/2 decode begin, ch: %d cpc %d \n", ch, c_p_c);
@ -1428,14 +1437,15 @@ static av_always_inline int vorbis_residue_decode_internal(vorbis_context *vc,
static inline int vorbis_residue_decode(vorbis_context *vc, vorbis_residue *vr,
unsigned ch,
uint8_t *do_not_decode,
float *vec, unsigned vlen)
float *vec, unsigned vlen,
unsigned ch_left)
{
if (vr->type == 2)
return vorbis_residue_decode_internal(vc, vr, ch, do_not_decode, vec, vlen, 2);
return vorbis_residue_decode_internal(vc, vr, ch, do_not_decode, vec, vlen, ch_left, 2);
else if (vr->type == 1)
return vorbis_residue_decode_internal(vc, vr, ch, do_not_decode, vec, vlen, 1);
return vorbis_residue_decode_internal(vc, vr, ch, do_not_decode, vec, vlen, ch_left, 1);
else if (vr->type == 0)
return vorbis_residue_decode_internal(vc, vr, ch, do_not_decode, vec, vlen, 0);
return vorbis_residue_decode_internal(vc, vr, ch, do_not_decode, vec, vlen, ch_left, 0);
else {
av_log(vc->avccontext, AV_LOG_ERROR, " Invalid residue type while residue decode?! \n");
return AVERROR_INVALIDDATA;
@ -1483,7 +1493,8 @@ static int vorbis_parse_audio_packet(vorbis_context *vc)
uint8_t res_chan[255];
unsigned res_num = 0;
int retlen = 0;
int ch_left = vc->audio_channels;
unsigned ch_left = vc->audio_channels;
unsigned vlen;
if (get_bits1(gb)) {
av_log(vc->avccontext, AV_LOG_ERROR, "Not a Vorbis I audio packet.\n");
@ -1503,11 +1514,12 @@ static int vorbis_parse_audio_packet(vorbis_context *vc)
blockflag = vc->modes[mode_number].blockflag;
blocksize = vc->blocksize[blockflag];
vlen = blocksize / 2;
if (blockflag)
skip_bits(gb, 2); // previous_window, next_window
memset(ch_res_ptr, 0, sizeof(float) * vc->audio_channels * blocksize / 2); //FIXME can this be removed ?
memset(ch_floor_ptr, 0, sizeof(float) * vc->audio_channels * blocksize / 2); //FIXME can this be removed ?
memset(ch_res_ptr, 0, sizeof(float) * vc->audio_channels * vlen); //FIXME can this be removed ?
memset(ch_floor_ptr, 0, sizeof(float) * vc->audio_channels * vlen); //FIXME can this be removed ?
// Decode floor
@ -1527,7 +1539,7 @@ static int vorbis_parse_audio_packet(vorbis_context *vc)
return AVERROR_INVALIDDATA;
}
no_residue[i] = ret;
ch_floor_ptr += blocksize / 2;
ch_floor_ptr += vlen;
}
// Nonzero vector propagate
@ -1544,6 +1556,7 @@ static int vorbis_parse_audio_packet(vorbis_context *vc)
for (i = 0; i < mapping->submaps; ++i) {
vorbis_residue *residue;
unsigned ch = 0;
int ret;
for (j = 0; j < vc->audio_channels; ++j) {
if ((mapping->submaps == 1) || (i == mapping->mux[j])) {
@ -1562,9 +1575,11 @@ static int vorbis_parse_audio_packet(vorbis_context *vc)
av_log(vc->avccontext, AV_LOG_ERROR, "Too many channels in vorbis_floor_decode.\n");
return -1;
}
vorbis_residue_decode(vc, residue, ch, do_not_decode, ch_res_ptr, blocksize/2);
ret = vorbis_residue_decode(vc, residue, ch, do_not_decode, ch_res_ptr, vlen, ch_left);
if (ret < 0)
return ret;
ch_res_ptr += ch * blocksize / 2;
ch_res_ptr += ch * vlen;
ch_left -= ch;
}