Re: [PATCH 1/5] __fdelt_chk: Removed range check

["Carlos O'Donell" <carlos@redhat.com>]

On 04/13/2013 08:47 PM, KOSAKI Motohiro wrote:
> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
> ---
>  ChangeLog         |    5 +++++
>  debug/fdelt_chk.c |    8 +++-----
>  2 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/ChangeLog b/ChangeLog
> index 36efa0b..5311919 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,8 @@
> +2013-03-25  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
> +
> +	* debug/fdelt_chk.c (__fdelt_chk): Removed range check
> +	and renamed to __fdelt_nochk.
> +
>  2013-04-11  Carlos O'Donell  <carlos@redhat.com>
>  
>  	* math/libm-test.inc (cos_test): Fix PI/2 test.
> diff --git a/debug/fdelt_chk.c b/debug/fdelt_chk.c
> index d149476..6588be0 100644
> --- a/debug/fdelt_chk.c
> +++ b/debug/fdelt_chk.c
> @@ -19,11 +19,9 @@
>  
>  
>  long int
> -__fdelt_chk (long int d)
> +__fdelt_nochk (long int d)
>  {
> -  if (d < 0 || d >= FD_SETSIZE)
> -    __chk_fail ();
> -
>    return d / __NFDBITS;
>  }
> -strong_alias (__fdelt_chk, __fdelt_warn)
> +strong_alias (__fdelt_nochk, __fdelt_chk)
> +strong_alias (__fdelt_nochk, __fdelt_warn)
> 

Doesn't this mean that you will disable the runtime check
for FD_SETSIZE for all existing binaries?

That means that we would have to recompile all of the
applications again in order to get checking again using
the new symbols proposed in PATCH #2?

This is not sufficiently conservative. We want it the other
way around. A simple recompile of ruby should result in
a ruby that no longer needs to disable _FORTIFY_SOURCE
to work around FD_SETSIZE checks.

Cheers,
Carlos.