[PATCH BZ#20422] Do not allow asan/msan/tsan and fortify at the same time.

[Florian Weimer]

On 09/06/2016 10:58 AM, Yuri Gribov wrote:

>> We could conceivably guard every _chk wrapper (say __sprintf_chk) with
>>
>> #ifndef __fortify_no___sprintf_chk
>> …
>> #endif
>>
>> .  In sanitizer mode, for those wrappers you have deemed to be unnecessary,
>> the compiler would define these macros, so that glibc wouldn't install the
>> wrapper.
>
> Or just undefine _FORTIFY_SOURCE?

Well, but this way, you'll lose the completely unrelated alternative 
implementations which might still be useful because none of the 
sanitizers cover these aspects.

>> Another option would be to provide a glibc which has been compiled with the
>> required sanitizers, so that most interceptors become unnecessary.
>
> Two important things to consider:
> * sanitized Glibc will be slower (potentially much slower) than
> current approach (because interceptors are heavily optimized)

But in turn, you might uncover more bugs (mostly in glibc, but also in 
applications because the interceptors happen to be slightly off in the 
behavior they model).

> * I'm unaware of any plans to implement sanitized Glibc (even though
> prototype has been available for 1+ year)

I hope to get remove the last remaining nested functions soon, if that's 
any help.

Florian