[Bug libc/17879] New: Library is missing memset_s

[Bug libc/17879] New: Library is missing memset_s

[noloader at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17879

            Bug ID: 17879
           Summary: Library is missing memset_s
           Product: glibc
           Version: 2.20
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: libc
          Assignee: unassigned at sourceware dot org
          Reporter: noloader at gmail dot com
                CC: drepper.fsp at gmail dot com

memset_s is missing from the library.

I'm attempting to use memset_s to zero some memory. memset_s is guaranteed not
to be optimized away, so its appealing to use it rather than the alternatives. 
Zeroization is a process requirement, and I can't discard it.

bzero cannot be used because (1) its non-portable, and (2) its deprecated.

The volatile qualifier cannot be used because GCC interprets it to mean only
memory that can be changed by hardware (a more lenient interpretation by the
GCC folks would be very helpful. But it is what it is).

memset_s not available in 2.19:

  $ nm -D /lib/x86_64-linux-gnu/libc.so.6 | grep memset_s
  $
  $ ls -l /lib/x86_64-linux-gnu/libc.so.6 lrwxrwxrwx 1 root root 12 Dec  4
14:31 /lib/x86_64-linux-gnu/libc.so.6 -> libc-2.19.so

And checking out the latest, memset_s is not available in 2.20 (or is it
2.21?):

  $ git clone git://sourceware.org/git/glibc.git
  $ cd glibc
  $ grep -R -w memset_s *
  $

I understand the safer functions from TR 24731-1 are not popular, but there
should be no objections for a memset function that is not optimized away
(correct me here, please).

Please provide the memset_s for safety and portability.

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[Bug libc/17879] Library is missing memset_s

[joseph at codesourcery dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17879

--- Comment #1 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
New features should be proposed on libc-alpha, not in Bugzilla.  Please 
restart the discussions there, including a careful synthesis of the 
arguments from previous libc-alpha discussions of the issue to help the 
community in reaching consensus.

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[Bug libc/17879] Library is missing memset_s

[noloader at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17879

Jeffrey Walton <noloader at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |noloader at gmail dot com

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[Bug libc/17879] Library is missing memset_s

[msebor at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17879

Martin Sebor <msebor at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |msebor at redhat dot com

--- Comment #2 from Martin Sebor <msebor at redhat dot com> ---
The GCC -fno-builtin-memset option can be used to prevent compatible compilers
from optimizing away calls to memset that aren't strictly speaking necessary.

Regarding portability: memset_s is an optional feature of the C11 standard and
as such isn't really portable. (AFAIK, there also are no conforming C11
implementations that provide the optional Annex K in which the function is
defined.)

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[Bug string/17879] Library is missing memset_s

[jsm28 at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17879

Joseph Myers <jsm28 at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|libc                        |string

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