Re: Re: #define __MUSL__ in features.h

["dgutson ." <danielgutson@gmail.com>]

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On Thu, Mar 15, 2018 at 4:00 PM, dgutson . <danielgutson@gmail.com> wrote:

>
>
> On Thu, Mar 15, 2018 at 3:53 PM, Rich Felker <dalias@libc.org> wrote:
>
>> On Thu, Mar 15, 2018 at 03:48:32PM -0300, Martin Galvan wrote:
>> > 2018-03-15 15:39 GMT-03:00 Rich Felker <dalias@libc.org>:
>> > >> (e.g. the FD* issue reported by Martin Galvan).
>> > >
>> > > That's not a bug. It's compiler warnings being wrongly produced for a
>> > > system header, probably because someone added -I/usr/include or
>> > > similar (normally GCC suppresses these).
>> >
>> > I'm certain we didn't add -I/usr/include or something similar. Could
>> > you test this yourself to confirm it's not a bug?
>>
>> In any case it's not a bug in musl. The code is perfectly valid C. If
>> the compiler is producing a warning for it, either ignore it or ask
>> the compiler to stop.
>>
>> > The compiler warnings aren't being wrongly produced. musl will indeed
>> > perform a signed-to-unsigned conversion here.
>>
>> Because that's how the C language works.
>>
>
> it is a potential vulnerability:
> https://cwe.mitre.org/data/definitions/195.html
> https://wiki.sei.cmu.edu/confluence/display/c/INT31-C.+
> Ensure+that+integer+conversions+do+not+result+in+
> lost+or+misinterpreted+data
> https://wiki.sei.cmu.edu/confluence/display/c/INT30-C.+
> Ensure+that+unsigned+integer+operations+do+not+wrap
>

Just to add: the code doesn't not comply with MISRA 2004 because it
violates 6.10.3. IOW, at least this issue turns musl MISRA non-compliant.


>
>
> Can you ensure it is rocksolid and the signed integer will NEVER be a
> negative value?
>
>
>>
>> > > The musl policy regarding not having a macro like __MUSL__ is doing
>> > > exactly what it's intended to do: encouraging developers and package
>> > > maintainers to come to us (or investigate on their own) and fix the
>> > > underlying portability problems (and sometimes musl bugs) rather than
>> > > writing hacks to a specific version of musl that will be wrong a few
>> > > versions later.
>> >
>> > So whenever we find a bug on musl we should just stop all our
>> > development until you've fixed the bug?
>>
>> No. As noted above, if you need to support systems that might have bug
>> X, you write a test (configure-time or run-time as appropriate) to
>> detect bug X and handle it.
>>
>> Rich
>>
>
>
>
> --
> Who’s got the sweetest disposition?
> One guess, that’s who?
> Who’d never, ever start an argument?
> Who never shows a bit of temperament?
> Who's never wrong but always right?
> Who'd never dream of starting a fight?
> Who get stuck with all the bad luck?
>



-- 
Who’s got the sweetest disposition?
One guess, that’s who?
Who’d never, ever start an argument?
Who never shows a bit of temperament?
Who's never wrong but always right?
Who'd never dream of starting a fight?
Who get stuck with all the bad luck?

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