avcodec/exr: Check buf_size more completely

Fixes: Out of heap array read
Fixes: 4683/clusterfuzz-testcase-minimized-6152313673613312

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2017-12-29 03:00:19 +01:00
parent c0b08ef94f
commit 903be5e4f6

View File

@ -1051,7 +1051,7 @@ static int decode_block(AVCodecContext *avctx, void *tdata,
line_offset = AV_RL64(s->gb.buffer + jobnr * 8);
if (s->is_tile) {
if (line_offset > buf_size - 20)
if (buf_size < 20 || line_offset > buf_size - 20)
return AVERROR_INVALIDDATA;
src = buf + line_offset + 20;
@ -1062,7 +1062,7 @@ static int decode_block(AVCodecContext *avctx, void *tdata,
tile_level_y = AV_RL32(src - 8);
data_size = AV_RL32(src - 4);
if (data_size <= 0 || data_size > buf_size)
if (data_size <= 0 || data_size > buf_size - line_offset - 20)
return AVERROR_INVALIDDATA;
if (tile_level_x || tile_level_y) { /* tile level, is not the full res level */
@ -1095,7 +1095,7 @@ static int decode_block(AVCodecContext *avctx, void *tdata,
td->channel_line_size = td->xsize * s->current_channel_offset;/* uncompress size of one line */
uncompressed_size = td->channel_line_size * (uint64_t)td->ysize;/* uncompress size of the block */
} else {
if (line_offset > buf_size - 8)
if (buf_size < 8 || line_offset > buf_size - 8)
return AVERROR_INVALIDDATA;
src = buf + line_offset + 8;
@ -1105,7 +1105,7 @@ static int decode_block(AVCodecContext *avctx, void *tdata,
return AVERROR_INVALIDDATA;
data_size = AV_RL32(src - 4);
if (data_size <= 0 || data_size > buf_size)
if (data_size <= 0 || data_size > buf_size - line_offset - 8)
return AVERROR_INVALIDDATA;
td->ysize = FFMIN(s->scan_lines_per_block, s->ymax - line + 1); /* s->ydelta - line ?? */