[FFmpeg-devel] [PATCH 1/2] avcodec: add mvdv video decoder

[Paul B Mahol]

On 11/25/19, Tomas Härdin <tjoppen at acc.umu.se> wrote:
> mån 2019-11-25 klockan 22:09 +0100 skrev Paul B Mahol:
>> Signed-off-by: Paul B Mahol <onemda at gmail.com>
>> +static int decode_mvdv(MidiVidContext *s, AVCodecContext *avctx, AVFrame
>> *frame)
>> +{
>> +    GetByteContext *gb = &s->gb;
>> +    GetBitContext mask;
>> +    GetByteContext idx9;
>> +    uint16_t nb_vectors, intra_flag;
>> +    const uint8_t *vec;
>> +    const uint8_t *mask_start;
>> +    uint8_t *skip;
>> +    int mask_size;
>> +    int idx9bits = 0;
>> +    int idx9val = 0;
>> +    int num_blocks;
>> +
>> +    nb_vectors = bytestream2_get_le16(gb);
>> +    intra_flag = bytestream2_get_le16(gb);
>> +    if (intra_flag) {
>> +        num_blocks = (avctx->width / 2) * (avctx->height / 2);
>
> Will UB if width*height/4 > INT_MAX
>
>> +    } else {
>> +        int skip_linesize;
>> +
>> +        num_blocks = bytestream2_get_le32(gb);
>
> Might want to use uint32_t so this doesn't lead to weirdness on 32-bit
>
>> +        skip_linesize = avctx->width >> 1;
>> +        mask_start = gb->buffer_start + bytestream2_tell(gb);
>> +        mask_size = (avctx->width >> 5) * (avctx->height >> 2);
>
> This can also UB
>
> /Tomas
>
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Nothing of this can actually happen.

Applied.