On Thu, Nov 17, 2016 at 01:08:31AM +0100, Andreas Cadhalpun wrote:
> All the fields can be set via options read from the ffm file and thus
> have to be sanitized.
>
> A negative extradata size for example gets passed to memcpy in
> avcodec_parameters_from_context causing a segmentation fault.
>
> Signed-off-by: Andreas Cadhalpun <andreas.cadhal...@googlemail.com>
> ---
>
> The other fields like qmin etc. seem to be completely ignored since the
> switch to codecpar, except possibly by ffserver.
>
> ---
> libavformat/ffmdec.c | 138
> +++++++++++++++++++++++++++++++++++++--------------
> 1 file changed, 102 insertions(+), 36 deletions(-)
>
> diff --git a/libavformat/ffmdec.c b/libavformat/ffmdec.c
> index 6b09be2..e66ba5c 100644
> --- a/libavformat/ffmdec.c
> +++ b/libavformat/ffmdec.c
> @@ -21,6 +21,7 @@
>
> #include <stdint.h>
>
> +#include "libavutil/imgutils.h"
> #include "libavutil/internal.h"
> #include "libavutil/intreadwrite.h"
> #include "libavutil/intfloat.h"
> @@ -28,6 +29,7 @@
> #include "libavutil/avassert.h"
> #include "libavutil/avstring.h"
> #include "libavutil/pixdesc.h"
> +#include "libavcodec/internal.h"
> #include "avformat.h"
> #include "internal.h"
> #include "ffm.h"
> @@ -277,6 +279,55 @@ static int ffm_append_recommended_configuration(AVStream
> *st, char **conf)
> return 0;
> }
>
> +#define SANITIZE_PARAMETER(parameter, name, check, default) {
> \
> + if (check) {
> \
> + av_log(codec, AV_LOG_WARNING, "Invalid " name " %d\n",
> codec->parameter); \
> + codec->parameter = default;
> \
> + }
> \
> +}
> +
> +static void ffm_sanitize_parameters(AVCodecContext *codec)
> +{
> + if (codec->time_base.num < 0 || codec->time_base.den <= 0) {
> + av_log(codec, AV_LOG_WARNING, "Invalid time base %d/%d\n",
> + codec->time_base.num, codec->time_base.den);
> + codec->time_base.num = 0;
> + codec->time_base.den = 1;
> + }
> + if (codec->bit_rate < 0) {
> + av_log(codec, AV_LOG_WARNING, "Invalid bit rate %"PRId64"\n",
> codec->bit_rate);
> + codec->bit_rate = 0;
> + }
> + if ((codec->width || codec->height) && av_image_check_size(codec->width,
> codec->height, 0, codec) < 0) {
> + codec->width = 0;
> + codec->height = 0;
> + }
> + if (codec->sample_aspect_ratio.num < 0 || codec->sample_aspect_ratio.den
> < 0) {
> + av_log(codec, AV_LOG_WARNING, "Invalid sample aspect ratio %d/%d\n",
> + codec->sample_aspect_ratio.num,
> codec->sample_aspect_ratio.den);
> + codec->sample_aspect_ratio.num = 0;
> + codec->sample_aspect_ratio.den = 1;
> + }
> + SANITIZE_PARAMETER(pix_fmt, "pixel format",
> codec->pix_fmt < AV_PIX_FMT_NONE || codec->pix_fmt > AV_PIX_FMT_NB,
> AV_PIX_FMT_NONE)
> + SANITIZE_PARAMETER(bits_per_coded_sample, "bits per coded sample",
> codec->bits_per_coded_sample < 0,
> 0)
> + SANITIZE_PARAMETER(bits_per_raw_sample, "bits per raw sample",
> codec->bits_per_raw_sample < 0,
> 0)
> + SANITIZE_PARAMETER(extradata_size, "extradata size",
> codec->extradata_size < 0 || codec->extradata_size >=
> FF_MAX_EXTRADATA_SIZE, 0)
> + SANITIZE_PARAMETER(color_range, "color range",
> (unsigned)codec->color_range > AVCOL_RANGE_NB,
> AVCOL_RANGE_UNSPECIFIED)
> + SANITIZE_PARAMETER(color_primaries, "color primaries",
> (unsigned)codec->color_primaries > AVCOL_PRI_NB,
> AVCOL_PRI_UNSPECIFIED)
> + SANITIZE_PARAMETER(color_trc, "color transfer
> characteristics ", (unsigned)codec->color_trc > AVCOL_TRC_NB,
> AVCOL_TRC_UNSPECIFIED)
> + SANITIZE_PARAMETER(colorspace, "color space",
> (unsigned)codec->colorspace > AVCOL_SPC_NB,
> AVCOL_SPC_UNSPECIFIED)
> + SANITIZE_PARAMETER(chroma_sample_location, "chroma location",
> (unsigned)codec->chroma_sample_location > AVCHROMA_LOC_NB,
> AVCHROMA_LOC_UNSPECIFIED)
> + SANITIZE_PARAMETER(has_b_frames, "video delay",
> codec->has_b_frames < 0,
> 0)
> + SANITIZE_PARAMETER(sample_fmt, "sample format",
> codec->sample_fmt < AV_SAMPLE_FMT_NONE || codec->sample_fmt >
> AV_SAMPLE_FMT_NB, AV_SAMPLE_FMT_NONE)This breaks API/ABI for example AVCOL_SPC_NB is not part of the public API of libavutil one should be able to use av_color_space_name() to detect invalid color spaces [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Opposition brings concord. Out of discord comes the fairest harmony. -- Heraclitus
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