[FFmpeg-devel] [PATCH 4/5] avcodec/sga: Check non constant init_get_bits8()
Andreas Rheinhardt
andreas.rheinhardt at outlook.com
Fri May 17 10:53:21 EEST 2024
Michael Niedermayer:
> Fixes: CID1473562 Unchecked return value
> Fixes: CID1473592 Unchecked return value
>
> Sponsored-by: Sovereign Tech Fund
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
> libavcodec/sga.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/libavcodec/sga.c b/libavcodec/sga.c
> index 0f42cf912b2..aca941e057e 100644
> --- a/libavcodec/sga.c
> +++ b/libavcodec/sga.c
> @@ -254,11 +254,14 @@ static int decode_palmapdata(AVCodecContext *avctx)
> const int bits = (s->nb_pal + 1) / 2;
> GetByteContext *gb = &s->gb;
> GetBitContext pm;
> + int ret;
>
> bytestream2_seek(gb, s->palmapdata_offset, SEEK_SET);
> if (bytestream2_get_bytes_left(gb) < s->palmapdata_size)
> return AVERROR_INVALIDDATA;
> - init_get_bits8(&pm, gb->buffer, s->palmapdata_size);
> + ret = init_get_bits8(&pm, gb->buffer, s->palmapdata_size);
> + if (ret < 0)
> + return ret;
>
> for (int y = 0; y < s->tiles_h; y++) {
> uint8_t *dst = s->palmapindex_data + y * s->tiles_w;
> @@ -277,11 +280,14 @@ static int decode_tiledata(AVCodecContext *avctx)
> SGAVideoContext *s = avctx->priv_data;
> GetByteContext *gb = &s->gb;
> GetBitContext tm;
> + int ret;
>
> bytestream2_seek(gb, s->tiledata_offset, SEEK_SET);
> if (bytestream2_get_bytes_left(gb) < s->tiledata_size)
> return AVERROR_INVALIDDATA;
> - init_get_bits8(&tm, gb->buffer, s->tiledata_size);
> + ret = init_get_bits8(&tm, gb->buffer, s->tiledata_size);
> + if (ret < 0)
> + return ret;
>
> for (int n = 0; n < s->nb_tiles; n++) {
> uint8_t *dst = s->tileindex_data + n * 64;
Both of these can not fail and could be checked via av_assert1:
palmapdata_size is given by (s->tiles_w * s->tiles_h * ((s->nb_pal + 1)
/ 2) + 7) / 8 with tiles_w and tiles_h being in the 0..255 range and
nb_pal being in the 0..4 range.
tiledata_size is given by s->nb_tiles * 32; nb_tiles fits in 16 bits (it
is either read via AV_RB16 or is given as the product of tiles_h *
tiles_w, both of which are read from simple uint8_t.
- Andreas
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