[FFmpeg-devel] [PATCH] avcodec: Ignoring errors is only possible before the input end

[FFmpeg-devel] [PATCH] avcodec: Ignoring errors is only possible before the input end

[Michael Niedermayer]

Fixes: out of array read
Fixes: Ticket 10308

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/h263dec.c       | 2 +-
 libavcodec/mpeg4videodec.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/libavcodec/h263dec.c b/libavcodec/h263dec.c
index f4e7048a5f..68a618a7ed 100644
--- a/libavcodec/h263dec.c
+++ b/libavcodec/h263dec.c
@@ -281,7 +281,7 @@ static int decode_slice(MpegEncContext *s)
                 ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
                                 s->mb_x, s->mb_y, ER_MB_ERROR & part_mask);
 
-                if (s->avctx->err_recognition & AV_EF_IGNORE_ERR)
+                if ((s->avctx->err_recognition & AV_EF_IGNORE_ERR) && get_bits_left(&s->gb) > 0)
                     continue;
                 return AVERROR_INVALIDDATA;
             }
diff --git a/libavcodec/mpeg4videodec.c b/libavcodec/mpeg4videodec.c
index d456e5dd11..30aec5e529 100644
--- a/libavcodec/mpeg4videodec.c
+++ b/libavcodec/mpeg4videodec.c
@@ -1437,7 +1437,7 @@ static inline int mpeg4_decode_block(Mpeg4DecContext *ctx, int16_t *block,
                                 if (SHOW_UBITS(re, &s->gb, 1) == 0) {
                                     av_log(s->avctx, AV_LOG_ERROR,
                                            "1. marker bit missing in 3. esc\n");
-                                    if (!(s->avctx->err_recognition & AV_EF_IGNORE_ERR))
+                                    if (!(s->avctx->err_recognition & AV_EF_IGNORE_ERR) || get_bits_left(&s->gb) <= 0)
                                         return AVERROR_INVALIDDATA;
                                 }
                                 SKIP_CACHE(re, &s->gb, 1);
@@ -1448,7 +1448,7 @@ static inline int mpeg4_decode_block(Mpeg4DecContext *ctx, int16_t *block,
                                 if (SHOW_UBITS(re, &s->gb, 1) == 0) {
                                     av_log(s->avctx, AV_LOG_ERROR,
                                            "2. marker bit missing in 3. esc\n");
-                                    if (!(s->avctx->err_recognition & AV_EF_IGNORE_ERR))
+                                    if (!(s->avctx->err_recognition & AV_EF_IGNORE_ERR) || get_bits_left(&s->gb) <= 0)
                                         return AVERROR_INVALIDDATA;
                                 }
 
-- 
2.17.1

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Re: [FFmpeg-devel] [PATCH] avcodec: Ignoring errors is only possible before the input end

[Paul B Mahol]

On Sat, Jun 3, 2023 at 9:44 PM Michael Niedermayer <michael@niedermayer.cc>
wrote:

> Fixes: out of array read
> Fixes: Ticket 10308
>

Did you forgot to apply this?


>
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavcodec/h263dec.c       | 2 +-
>  libavcodec/mpeg4videodec.c | 4 ++--
>  2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/libavcodec/h263dec.c b/libavcodec/h263dec.c
> index f4e7048a5f..68a618a7ed 100644
> --- a/libavcodec/h263dec.c
> +++ b/libavcodec/h263dec.c
> @@ -281,7 +281,7 @@ static int decode_slice(MpegEncContext *s)
>                  ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
>                                  s->mb_x, s->mb_y, ER_MB_ERROR &
> part_mask);
>
> -                if (s->avctx->err_recognition & AV_EF_IGNORE_ERR)
> +                if ((s->avctx->err_recognition & AV_EF_IGNORE_ERR) &&
> get_bits_left(&s->gb) > 0)
>                      continue;
>                  return AVERROR_INVALIDDATA;
>              }
> diff --git a/libavcodec/mpeg4videodec.c b/libavcodec/mpeg4videodec.c
> index d456e5dd11..30aec5e529 100644
> --- a/libavcodec/mpeg4videodec.c
> +++ b/libavcodec/mpeg4videodec.c
> @@ -1437,7 +1437,7 @@ static inline int mpeg4_decode_block(Mpeg4DecContext
> *ctx, int16_t *block,
>                                  if (SHOW_UBITS(re, &s->gb, 1) == 0) {
>                                      av_log(s->avctx, AV_LOG_ERROR,
>                                             "1. marker bit missing in 3.
> esc\n");
> -                                    if (!(s->avctx->err_recognition &
> AV_EF_IGNORE_ERR))
> +                                    if (!(s->avctx->err_recognition &
> AV_EF_IGNORE_ERR) || get_bits_left(&s->gb) <= 0)
>                                          return AVERROR_INVALIDDATA;
>                                  }
>                                  SKIP_CACHE(re, &s->gb, 1);
> @@ -1448,7 +1448,7 @@ static inline int mpeg4_decode_block(Mpeg4DecContext
> *ctx, int16_t *block,
>                                  if (SHOW_UBITS(re, &s->gb, 1) == 0) {
>                                      av_log(s->avctx, AV_LOG_ERROR,
>                                             "2. marker bit missing in 3.
> esc\n");
> -                                    if (!(s->avctx->err_recognition &
> AV_EF_IGNORE_ERR))
> +                                    if (!(s->avctx->err_recognition &
> AV_EF_IGNORE_ERR) || get_bits_left(&s->gb) <= 0)
>                                          return AVERROR_INVALIDDATA;
>                                  }
>
> --
> 2.17.1
>
> _______________________________________________
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> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>
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Re: [FFmpeg-devel] [PATCH] avcodec: Ignoring errors is only possible before the input end

[Michael Niedermayer]

[-- Attachment #1.1: Type: text/plain, Size: 477 bytes --]

On Sat, Jun 17, 2023 at 08:45:53AM +0200, Paul B Mahol wrote:
> On Sat, Jun 3, 2023 at 9:44 PM Michael Niedermayer <michael@niedermayer.cc>
> wrote:
> 
> > Fixes: out of array read
> > Fixes: Ticket 10308
> >
> 
> Did you forgot to apply this?

yes, ill apply it with my next git push

thx for reminding me

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No snowflake in an avalanche ever feels responsible. -- Voltaire

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