[FFmpeg-devel] [PATCH 08/25] avcodec/magicyuv: Replace implicit checks for overread by explicit ones
Paul B Mahol
onemda at gmail.com
Sat Sep 26 13:39:17 EEST 2020
On Sat, Sep 26, 2020 at 12:27:47PM +0200, Andreas Rheinhardt wrote:
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> ---
> libavcodec/magicyuv.c | 49 ++++++++++++++++++++++++-------------------
> 1 file changed, 27 insertions(+), 22 deletions(-)
>
> diff --git a/libavcodec/magicyuv.c b/libavcodec/magicyuv.c
> index 3413d8f298..93ee739093 100644
> --- a/libavcodec/magicyuv.c
> +++ b/libavcodec/magicyuv.c
> @@ -442,23 +442,26 @@ static int magy_decode_frame(AVCodecContext *avctx, void *data,
> MagicYUVContext *s = avctx->priv_data;
> ThreadFrame frame = { .f = data };
> AVFrame *p = data;
> - GetByteContext gbyte;
> + GetByteContext gb;
> uint32_t first_offset, offset, next_offset, header_size, slice_width;
> int width, height, format, version, table_size;
> int ret, i, j;
>
> - bytestream2_init(&gbyte, avpkt->data, avpkt->size);
> - if (bytestream2_get_le32(&gbyte) != MKTAG('M', 'A', 'G', 'Y'))
> + if (avpkt->size < 36)
> + return AVERROR_INVALIDDATA;
> +
> + bytestream2_init(&gb, avpkt->data, avpkt->size);
> + if (bytestream2_get_le32u(&gb) != MKTAG('M', 'A', 'G', 'Y'))
> return AVERROR_INVALIDDATA;
>
> - header_size = bytestream2_get_le32(&gbyte);
> + header_size = bytestream2_get_le32u(&gb);
> if (header_size < 32 || header_size >= avpkt->size) {
> av_log(avctx, AV_LOG_ERROR,
> "header or packet too small %"PRIu32"\n", header_size);
> return AVERROR_INVALIDDATA;
> }
>
> - version = bytestream2_get_byte(&gbyte);
> + version = bytestream2_get_byteu(&gb);
> if (version != 7) {
> avpriv_request_sample(avctx, "Version %d", version);
> return AVERROR_PATCHWELCOME;
> @@ -471,7 +474,7 @@ static int magy_decode_frame(AVCodecContext *avctx, void *data,
> s->decorrelate = 0;
> s->bps = 8;
>
> - format = bytestream2_get_byte(&gbyte);
> + format = bytestream2_get_byteu(&gb);
> switch (format) {
> case 0x65:
> avctx->pix_fmt = AV_PIX_FMT_GBRP;
> @@ -552,34 +555,34 @@ static int magy_decode_frame(AVCodecContext *avctx, void *data,
> s->magy_decode_slice = s->bps == 8 ? magy_decode_slice : magy_decode_slice10;
> s->planes = av_pix_fmt_count_planes(avctx->pix_fmt);
>
> - bytestream2_skip(&gbyte, 1);
> - s->color_matrix = bytestream2_get_byte(&gbyte);
> - s->flags = bytestream2_get_byte(&gbyte);
> + bytestream2_skipu(&gb, 1);
> + s->color_matrix = bytestream2_get_byteu(&gb);
> + s->flags = bytestream2_get_byteu(&gb);
> s->interlaced = !!(s->flags & 2);
> - bytestream2_skip(&gbyte, 3);
> + bytestream2_skipu(&gb, 3);
>
> - width = bytestream2_get_le32(&gbyte);
> - height = bytestream2_get_le32(&gbyte);
> + width = bytestream2_get_le32u(&gb);
> + height = bytestream2_get_le32u(&gb);
> ret = ff_set_dimensions(avctx, width, height);
> if (ret < 0)
> return ret;
>
> - slice_width = bytestream2_get_le32(&gbyte);
> + slice_width = bytestream2_get_le32u(&gb);
> if (slice_width != avctx->coded_width) {
> avpriv_request_sample(avctx, "Slice width %"PRIu32, slice_width);
> return AVERROR_PATCHWELCOME;
> }
> - s->slice_height = bytestream2_get_le32(&gbyte);
> + s->slice_height = bytestream2_get_le32u(&gb);
> if (s->slice_height <= 0 || s->slice_height > INT_MAX - avctx->coded_height) {
> av_log(avctx, AV_LOG_ERROR,
> "invalid slice height: %d\n", s->slice_height);
> return AVERROR_INVALIDDATA;
> }
>
> - bytestream2_skip(&gbyte, 4);
> + bytestream2_skipu(&gb, 4);
>
> s->nb_slices = (avctx->coded_height + s->slice_height - 1) / s->slice_height;
> - if (s->nb_slices > INT_MAX / sizeof(Slice)) {
> + if (s->nb_slices > INT_MAX / FFMAX(sizeof(Slice), 4 * 5)) {
> av_log(avctx, AV_LOG_ERROR,
> "invalid number of slices: %d\n", s->nb_slices);
> return AVERROR_INVALIDDATA;
> @@ -596,12 +599,14 @@ static int magy_decode_frame(AVCodecContext *avctx, void *data,
> }
> }
>
> + if (bytestream2_get_bytes_left(&gb) <= s->nb_slices * s->planes * 5)
> + return AVERROR_INVALIDDATA;
>From where you picked this 5 number?
> for (i = 0; i < s->planes; i++) {
> av_fast_malloc(&s->slices[i], &s->slices_size[i], s->nb_slices * sizeof(Slice));
> if (!s->slices[i])
> return AVERROR(ENOMEM);
>
> - offset = bytestream2_get_le32(&gbyte);
> + offset = bytestream2_get_le32u(&gb);
> if (offset >= avpkt->size - header_size)
> return AVERROR_INVALIDDATA;
>
> @@ -611,7 +616,7 @@ static int magy_decode_frame(AVCodecContext *avctx, void *data,
> for (j = 0; j < s->nb_slices - 1; j++) {
> s->slices[i][j].start = offset + header_size;
>
> - next_offset = bytestream2_get_le32(&gbyte);
> + next_offset = bytestream2_get_le32u(&gb);
> if (next_offset <= offset || next_offset >= avpkt->size - header_size)
> return AVERROR_INVALIDDATA;
>
> @@ -625,16 +630,16 @@ static int magy_decode_frame(AVCodecContext *avctx, void *data,
> s->slices[i][j].size = avpkt->size - s->slices[i][j].start;
> }
>
> - if (bytestream2_get_byte(&gbyte) != s->planes)
> + if (bytestream2_get_byteu(&gb) != s->planes)
> return AVERROR_INVALIDDATA;
>
> - bytestream2_skip(&gbyte, s->nb_slices * s->planes);
> + bytestream2_skipu(&gb, s->nb_slices * s->planes);
>
> - table_size = header_size + first_offset - bytestream2_tell(&gbyte);
> + table_size = header_size + first_offset - bytestream2_tell(&gb);
> if (table_size < 2)
> return AVERROR_INVALIDDATA;
>
> - ret = build_huffman(avctx, avpkt->data + bytestream2_tell(&gbyte),
> + ret = build_huffman(avctx, avpkt->data + bytestream2_tell(&gb),
> table_size, s->max);
> if (ret < 0)
> return ret;
> --
> 2.25.1
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
More information about the ffmpeg-devel
mailing list