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Bounds-check macroblock/motion/audio indices to fix four OOB accesses (#73) #74

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Bounds-check macroblock/motion/audio indices to fix four OOB accesses (#73) #74

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13 changes: 9 additions & 4 deletions pl_mpeg.h
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Original file line number Diff line number Diff line change
Expand Up @@ -3189,7 +3189,8 @@ void plm_video_decode_macroblock(plm_video_t *self) {
self->mb_row = self->macroblock_address / self->mb_width;
self->mb_col = self->macroblock_address % self->mb_width;

if (self->mb_col >= self->mb_width || self->mb_row >= self->mb_height) {
if (self->mb_col < 0 || self->mb_col >= self->mb_width ||
self->mb_row < 0 || self->mb_row >= self->mb_height) {
return; // corrupt stream;
}

Expand Down Expand Up @@ -3356,8 +3357,12 @@ void plm_video_process_macroblock(
unsigned int si = ((self->mb_row * block_size) + vp) * dw + (self->mb_col * block_size) + hp;
unsigned int di = (self->mb_row * dw + self->mb_col) * block_size;

unsigned int max_address = (dw * (self->mb_height * block_size - block_size + 1) - block_size);
if (si > max_address || di > max_address) {
unsigned int plane_size = (unsigned int)dw * (self->mb_height * block_size);
unsigned int block_span = (unsigned int)(block_size - 1) * dw + (block_size - 1);
unsigned int src_extra = (odd_v ? (unsigned int)dw : 0) + (odd_h ? 1u : 0);
if (si >= plane_size || di >= plane_size ||
si + block_span + src_extra >= plane_size ||
di + block_span >= plane_size) {
return; // corrupt video
}

Expand Down Expand Up @@ -4026,7 +4031,7 @@ int plm_audio_decode_header(plm_audio_t *self) {
}

int bitrate_index = plm_buffer_read(self->buffer, 4) - 1;
if (bitrate_index > 13) {
if (bitrate_index < 0 || bitrate_index > 13) {
return 0;
}

Expand Down