demux: move padded size calc post unpadded validation

though the max chunk/payload sizes were checked and would fail the
padded size was being calculated beforehand which could result in a
(harmless) unsigned int overflow warning.

Bug: webp:508
Change-Id: I4fa30ded2b027c1577b03049a2deeb7bf75e5472
This commit is contained in:
James Zern 2021-05-15 10:59:06 -07:00
parent 05b72d4205
commit 6fb4cddc93

View File

@ -221,12 +221,16 @@ static ParseStatus StoreFrame(int frame_num, uint32_t min_size,
const size_t chunk_start_offset = mem->start_;
const uint32_t fourcc = ReadLE32(mem);
const uint32_t payload_size = ReadLE32(mem);
const uint32_t payload_size_padded = payload_size + (payload_size & 1);
const size_t payload_available = (payload_size_padded > MemDataSize(mem))
? MemDataSize(mem) : payload_size_padded;
const size_t chunk_size = CHUNK_HEADER_SIZE + payload_available;
uint32_t payload_size_padded;
size_t payload_available;
size_t chunk_size;
if (payload_size > MAX_CHUNK_PAYLOAD) return PARSE_ERROR;
payload_size_padded = payload_size + (payload_size & 1);
payload_available = (payload_size_padded > MemDataSize(mem))
? MemDataSize(mem) : payload_size_padded;
chunk_size = CHUNK_HEADER_SIZE + payload_available;
if (SizeIsInvalid(mem, payload_size_padded)) return PARSE_ERROR;
if (payload_size_padded > MemDataSize(mem)) status = PARSE_NEED_MORE_DATA;
@ -451,9 +455,11 @@ static ParseStatus ParseVP8XChunks(WebPDemuxer* const dmux) {
const size_t chunk_start_offset = mem->start_;
const uint32_t fourcc = ReadLE32(mem);
const uint32_t chunk_size = ReadLE32(mem);
const uint32_t chunk_size_padded = chunk_size + (chunk_size & 1);
uint32_t chunk_size_padded;
if (chunk_size > MAX_CHUNK_PAYLOAD) return PARSE_ERROR;
chunk_size_padded = chunk_size + (chunk_size & 1);
if (SizeIsInvalid(mem, chunk_size_padded)) return PARSE_ERROR;
switch (fourcc) {