[FFmpeg-devel] [PATCH v2] configure: Clearer documentation for "disable-safe-bitstream-reader"

[FFmpeg-devel] [PATCH v2] configure: Clearer documentation for "disable-safe-bitstream-reader"

[Michael Niedermayer]

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 configure | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/configure b/configure
index bd4f8723760..f1db8b6f235 100755
--- a/configure
+++ b/configure
@@ -436,7 +436,8 @@ Advanced options (experts only):
   --enable-hardcoded-tables use hardcoded tables instead of runtime generation
   --disable-safe-bitstream-reader
                            disable buffer boundary checking in bitreaders
-                           (faster, but may crash)
+                           (This disables some security checks and can cause undefined behavior,
+                            it may be faster, but should only be used with trusted input)
   --sws-max-filter-size=N  the max filter size swscale uses [$sws_max_filter_size_default]
 
 Optimization options (experts only):
-- 
2.49.0

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Re: [FFmpeg-devel] [PATCH v2] configure: Clearer documentation for "disable-safe-bitstream-reader"

[Andreas Rheinhardt]

Michael Niedermayer:
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  configure | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/configure b/configure
> index bd4f8723760..f1db8b6f235 100755
> --- a/configure
> +++ b/configure
> @@ -436,7 +436,8 @@ Advanced options (experts only):
>    --enable-hardcoded-tables use hardcoded tables instead of runtime generation
>    --disable-safe-bitstream-reader
>                             disable buffer boundary checking in bitreaders
> -                           (faster, but may crash)
> +                           (This disables some security checks and can cause undefined behavior,
> +                            it may be faster, but should only be used with trusted input)
>    --sws-max-filter-size=N  the max filter size swscale uses [$sws_max_filter_size_default]
>  
>  Optimization options (experts only):

I'd like to keep "crash" in the description. Not everyone (not even
people setting "experts only" options) will be familiar with the term
"undefined behavior".

- Andreas

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Re: [FFmpeg-devel] [PATCH v2] configure: Clearer documentation for "disable-safe-bitstream-reader"

[Michael Niedermayer]

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On Fri, Apr 11, 2025 at 08:32:55AM +0200, Andreas Rheinhardt wrote:
> Michael Niedermayer:
> > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> > ---
> >  configure | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/configure b/configure
> > index bd4f8723760..f1db8b6f235 100755
> > --- a/configure
> > +++ b/configure
> > @@ -436,7 +436,8 @@ Advanced options (experts only):
> >    --enable-hardcoded-tables use hardcoded tables instead of runtime generation
> >    --disable-safe-bitstream-reader
> >                             disable buffer boundary checking in bitreaders
> > -                           (faster, but may crash)
> > +                           (This disables some security checks and can cause undefined behavior,
> > +                            it may be faster, but should only be used with trusted input)
> >    --sws-max-filter-size=N  the max filter size swscale uses [$sws_max_filter_size_default]
> >  
> >  Optimization options (experts only):
> 
> I'd like to keep "crash" in the description. Not everyone (not even
> people setting "experts only" options) will be familiar with the term
> "undefined behavior".

what about:

(This disables some security checks and can cause undefined behavior and
 crashes, it may be faster, but should only be used with trusted input)

?

thx

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

I am the wisest man alive, for I know one thing, and that is that I know
nothing. -- Socrates

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Re: [FFmpeg-devel] [PATCH v2] configure: Clearer documentation for "disable-safe-bitstream-reader"

[Timo Rothenpieler]

On 12.04.2025 02:11, Michael Niedermayer wrote:
> On Fri, Apr 11, 2025 at 08:32:55AM +0200, Andreas Rheinhardt wrote:
>> Michael Niedermayer:
>>> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
>>> ---
>>>   configure | 3 ++-
>>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/configure b/configure
>>> index bd4f8723760..f1db8b6f235 100755
>>> --- a/configure
>>> +++ b/configure
>>> @@ -436,7 +436,8 @@ Advanced options (experts only):
>>>     --enable-hardcoded-tables use hardcoded tables instead of runtime generation
>>>     --disable-safe-bitstream-reader
>>>                              disable buffer boundary checking in bitreaders
>>> -                           (faster, but may crash)
>>> +                           (This disables some security checks and can cause undefined behavior,
>>> +                            it may be faster, but should only be used with trusted input)
>>>     --sws-max-filter-size=N  the max filter size swscale uses [$sws_max_filter_size_default]
>>>   
>>>   Optimization options (experts only):
>>
>> I'd like to keep "crash" in the description. Not everyone (not even
>> people setting "experts only" options) will be familiar with the term
>> "undefined behavior".
> 
> what about:
> 
> (This disables some security checks and can cause undefined behavior and
>   crashes, it may be faster, but should only be used with trusted input)

Given that the undefined behaviour can in theory even include arbitrary 
code execution, I'd probably make it even harsher and mention that 
worst-case being a possibility.
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Re: [FFmpeg-devel] [PATCH v2] configure: Clearer documentation for "disable-safe-bitstream-reader"

[Michael Niedermayer]

[-- Attachment #1.1: Type: text/plain, Size: 2168 bytes --]

On Sat, Apr 12, 2025 at 02:19:08AM +0200, Timo Rothenpieler wrote:
> On 12.04.2025 02:11, Michael Niedermayer wrote:
> > On Fri, Apr 11, 2025 at 08:32:55AM +0200, Andreas Rheinhardt wrote:
> > > Michael Niedermayer:
> > > > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> > > > ---
> > > >   configure | 3 ++-
> > > >   1 file changed, 2 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/configure b/configure
> > > > index bd4f8723760..f1db8b6f235 100755
> > > > --- a/configure
> > > > +++ b/configure
> > > > @@ -436,7 +436,8 @@ Advanced options (experts only):
> > > >     --enable-hardcoded-tables use hardcoded tables instead of runtime generation
> > > >     --disable-safe-bitstream-reader
> > > >                              disable buffer boundary checking in bitreaders
> > > > -                           (faster, but may crash)
> > > > +                           (This disables some security checks and can cause undefined behavior,
> > > > +                            it may be faster, but should only be used with trusted input)
> > > >     --sws-max-filter-size=N  the max filter size swscale uses [$sws_max_filter_size_default]
> > > >   Optimization options (experts only):
> > > 
> > > I'd like to keep "crash" in the description. Not everyone (not even
> > > people setting "experts only" options) will be familiar with the term
> > > "undefined behavior".
> > 
> > what about:
> > 
> > (This disables some security checks and can cause undefined behavior and
> >   crashes, it may be faster, but should only be used with trusted input)
> 
> Given that the undefined behaviour can in theory even include arbitrary code
> execution, I'd probably make it even harsher and mention that worst-case
> being a possibility.

what about this:

(This disables some security checks and can cause undefined behavior,
 crashes and arbitrary code execution, it may be faster, but
 should only be used with trusted input)

?

thx

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

He who knows, does not speak. He who speaks, does not know. -- Lao Tsu

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Re: [FFmpeg-devel] [PATCH v2] configure: Clearer documentation for "disable-safe-bitstream-reader"

[Michael Niedermayer]

[-- Attachment #1.1: Type: text/plain, Size: 2391 bytes --]

On Sat, Apr 12, 2025 at 02:42:11AM +0200, Michael Niedermayer wrote:
> On Sat, Apr 12, 2025 at 02:19:08AM +0200, Timo Rothenpieler wrote:
> > On 12.04.2025 02:11, Michael Niedermayer wrote:
> > > On Fri, Apr 11, 2025 at 08:32:55AM +0200, Andreas Rheinhardt wrote:
> > > > Michael Niedermayer:
> > > > > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> > > > > ---
> > > > >   configure | 3 ++-
> > > > >   1 file changed, 2 insertions(+), 1 deletion(-)
> > > > > 
> > > > > diff --git a/configure b/configure
> > > > > index bd4f8723760..f1db8b6f235 100755
> > > > > --- a/configure
> > > > > +++ b/configure
> > > > > @@ -436,7 +436,8 @@ Advanced options (experts only):
> > > > >     --enable-hardcoded-tables use hardcoded tables instead of runtime generation
> > > > >     --disable-safe-bitstream-reader
> > > > >                              disable buffer boundary checking in bitreaders
> > > > > -                           (faster, but may crash)
> > > > > +                           (This disables some security checks and can cause undefined behavior,
> > > > > +                            it may be faster, but should only be used with trusted input)
> > > > >     --sws-max-filter-size=N  the max filter size swscale uses [$sws_max_filter_size_default]
> > > > >   Optimization options (experts only):
> > > > 
> > > > I'd like to keep "crash" in the description. Not everyone (not even
> > > > people setting "experts only" options) will be familiar with the term
> > > > "undefined behavior".
> > > 
> > > what about:
> > > 
> > > (This disables some security checks and can cause undefined behavior and
> > >   crashes, it may be faster, but should only be used with trusted input)
> > 
> > Given that the undefined behaviour can in theory even include arbitrary code
> > execution, I'd probably make it even harsher and mention that worst-case
> > being a possibility.
> 
> what about this:
> 
> (This disables some security checks and can cause undefined behavior,
>  crashes and arbitrary code execution, it may be faster, but
>  should only be used with trusted input)

will apply, feel free to change if someone has ideas for improvment

thx

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Those who are best at talking, realize last or never when they are wrong.

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