[FFmpeg-devel] [PATCH] avformat/asfdec_f: Check amount of value read

[FFmpeg-devel] [PATCH] avformat/asfdec_f: Check amount of value read

[Michael Niedermayer]

Fixes: use of uninitialized memory
Fixes: 403675492/clusterfuzz-testcase-minimized-ffmpeg_dem_ASF_fuzzer-4754281823797248

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavformat/asfdec_f.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libavformat/asfdec_f.c b/libavformat/asfdec_f.c
index ea6e8ef4f3a..10f5dea57c3 100644
--- a/libavformat/asfdec_f.c
+++ b/libavformat/asfdec_f.c
@@ -241,7 +241,9 @@ static void get_tag(AVFormatContext *s, const char *key, int type, int len, int
         avio_get_str16le(s->pb, len, value, 2 * len + 1);
         break;
     case -1: // ASCI
-        avio_read(s->pb, value, len);
+       ;int ret = ffio_read_size(s->pb, value, len);
+        if (ret < 0)
+            goto finish;
         value[len]=0;
         break;
     case ASF_BYTE_ARRAY:
-- 
2.49.0

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Re: [FFmpeg-devel] [PATCH] avformat/asfdec_f: Check amount of value read

[Kacper Michajlow]

On Wed, 23 Jul 2025 at 10:43, Michael Niedermayer
<michael@niedermayer.cc> wrote:
>
> Fixes: use of uninitialized memory
> Fixes: 403675492/clusterfuzz-testcase-minimized-ffmpeg_dem_ASF_fuzzer-4754281823797248
>
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavformat/asfdec_f.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/libavformat/asfdec_f.c b/libavformat/asfdec_f.c
> index ea6e8ef4f3a..10f5dea57c3 100644
> --- a/libavformat/asfdec_f.c
> +++ b/libavformat/asfdec_f.c
> @@ -241,7 +241,9 @@ static void get_tag(AVFormatContext *s, const char *key, int type, int len, int
>          avio_get_str16le(s->pb, len, value, 2 * len + 1);
>          break;
>      case -1: // ASCI
> -        avio_read(s->pb, value, len);
> +       ;int ret = ffio_read_size(s->pb, value, len);

stray ;

> +        if (ret < 0)
> +            goto finish;
>          value[len]=0;
>          break;
>      case ASF_BYTE_ARRAY:
> --
> 2.49.0
>
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Re: [FFmpeg-devel] [PATCH] avformat/asfdec_f: Check amount of value read

[Michael Niedermayer]

[-- Attachment #1.1: Type: text/plain, Size: 1624 bytes --]

On Wed, Jul 23, 2025 at 05:51:35PM +0200, Kacper Michajlow wrote:
> On Wed, 23 Jul 2025 at 10:43, Michael Niedermayer
> <michael@niedermayer.cc> wrote:
> >
> > Fixes: use of uninitialized memory
> > Fixes: 403675492/clusterfuzz-testcase-minimized-ffmpeg_dem_ASF_fuzzer-4754281823797248
> >
> > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> > ---
> >  libavformat/asfdec_f.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/libavformat/asfdec_f.c b/libavformat/asfdec_f.c
> > index ea6e8ef4f3a..10f5dea57c3 100644
> > --- a/libavformat/asfdec_f.c
> > +++ b/libavformat/asfdec_f.c
> > @@ -241,7 +241,9 @@ static void get_tag(AVFormatContext *s, const char *key, int type, int len, int
> >          avio_get_str16le(s->pb, len, value, 2 * len + 1);
> >          break;
> >      case -1: // ASCI
> > -        avio_read(s->pb, value, len);
> > +       ;int ret = ffio_read_size(s->pb, value, len);
> 
> stray ;

no, try remove it :)

libavformat/asfdec_f.c: In function ‘get_tag’:
libavformat/asfdec_f.c:244:9: error: a label can only be part of a statement and a declaration is not a statement
  244 |         int ret = ffio_read_size(s->pb, value, len);
      |         ^~~

thx

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The bravest are surely those who have the clearest vision
of what is before them, glory and danger alike, and yet
notwithstanding go out to meet it. -- Thucydides

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Re: [FFmpeg-devel] [PATCH] avformat/asfdec_f: Check amount of value read

[Kacper Michajlow]

On Sun, 27 Jul 2025 at 22:57, Michael Niedermayer
<michael@niedermayer.cc> wrote:
>
> On Wed, Jul 23, 2025 at 05:51:35PM +0200, Kacper Michajlow wrote:
> > On Wed, 23 Jul 2025 at 10:43, Michael Niedermayer
> > <michael@niedermayer.cc> wrote:
> > >
> > > Fixes: use of uninitialized memory
> > > Fixes: 403675492/clusterfuzz-testcase-minimized-ffmpeg_dem_ASF_fuzzer-4754281823797248
> > >
> > > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> > > ---
> > >  libavformat/asfdec_f.c | 4 +++-
> > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/libavformat/asfdec_f.c b/libavformat/asfdec_f.c
> > > index ea6e8ef4f3a..10f5dea57c3 100644
> > > --- a/libavformat/asfdec_f.c
> > > +++ b/libavformat/asfdec_f.c
> > > @@ -241,7 +241,9 @@ static void get_tag(AVFormatContext *s, const char *key, int type, int len, int
> > >          avio_get_str16le(s->pb, len, value, 2 * len + 1);
> > >          break;
> > >      case -1: // ASCI
> > > -        avio_read(s->pb, value, len);
> > > +       ;int ret = ffio_read_size(s->pb, value, len);
> >
> > stray ;
>
> no, try remove it :)
>
> libavformat/asfdec_f.c: In function ‘get_tag’:
> libavformat/asfdec_f.c:244:9: error: a label can only be part of a statement and a declaration is not a statement
>   244 |         int ret = ffio_read_size(s->pb, value, len);
>       |         ^~~

Ah, right. It's the first line after the case statement.

I generally put it immediately after : `case -1:;`. It was looking off
at the beginning of the line, but all good :)

- Kacper
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Re: [FFmpeg-devel] [PATCH] avformat/asfdec_f: Check amount of value read

[Michael Niedermayer]

[-- Attachment #1.1: Type: text/plain, Size: 2043 bytes --]

On Mon, Jul 28, 2025 at 01:10:57AM +0200, Kacper Michajlow wrote:
> On Sun, 27 Jul 2025 at 22:57, Michael Niedermayer
> <michael@niedermayer.cc> wrote:
> >
> > On Wed, Jul 23, 2025 at 05:51:35PM +0200, Kacper Michajlow wrote:
> > > On Wed, 23 Jul 2025 at 10:43, Michael Niedermayer
> > > <michael@niedermayer.cc> wrote:
> > > >
> > > > Fixes: use of uninitialized memory
> > > > Fixes: 403675492/clusterfuzz-testcase-minimized-ffmpeg_dem_ASF_fuzzer-4754281823797248
> > > >
> > > > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > > > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> > > > ---
> > > >  libavformat/asfdec_f.c | 4 +++-
> > > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/libavformat/asfdec_f.c b/libavformat/asfdec_f.c
> > > > index ea6e8ef4f3a..10f5dea57c3 100644
> > > > --- a/libavformat/asfdec_f.c
> > > > +++ b/libavformat/asfdec_f.c
> > > > @@ -241,7 +241,9 @@ static void get_tag(AVFormatContext *s, const char *key, int type, int len, int
> > > >          avio_get_str16le(s->pb, len, value, 2 * len + 1);
> > > >          break;
> > > >      case -1: // ASCI
> > > > -        avio_read(s->pb, value, len);
> > > > +       ;int ret = ffio_read_size(s->pb, value, len);
> > >
> > > stray ;
> >
> > no, try remove it :)
> >
> > libavformat/asfdec_f.c: In function ‘get_tag’:
> > libavformat/asfdec_f.c:244:9: error: a label can only be part of a statement and a declaration is not a statement
> >   244 |         int ret = ffio_read_size(s->pb, value, len);
> >       |         ^~~
> 
> Ah, right. It's the first line after the case statement.
> 
> I generally put it immediately after : `case -1:;`. It was looking off
> at the beginning of the line, but all good :)

ill move to after the :

thx

[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The misfortune of the wise is better than the prosperity of the fool.
-- Epicurus

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