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

[Tomas Härdin]

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