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Re: gl_{,SN}PRINTF_DIRECTIVE_N wrongly fail on Ubuntu 18.04
From: |
Adrian Bunk |
Subject: |
Re: gl_{,SN}PRINTF_DIRECTIVE_N wrongly fail on Ubuntu 18.04 |
Date: |
Mon, 9 Mar 2020 01:38:55 +0200 |
User-agent: |
Mutt/1.10.1 (2018-07-13) |
On Sun, Mar 08, 2020 at 11:04:40PM +0100, Bruno Haible wrote:
> Hi Adrian,
Hi Bruno,
>...
> it would
> make sense for gnulib to have "nearly POSIX" compliant variants of these
> functions; this would remove the need for the gnulib *printf* code in
> many cases.
this sounds like a good idea.
Looking at git history the usage in bison this is due to
https://lists.gnu.org/archive/html/bug-gnulib/2009-10/msg00143.html
gzip is due to
http://git.savannah.gnu.org/cgit/gzip.git/commit/?id=bc4b1e68a8da345c6027dd034592f66808a6f254
So -DGNULIB_POSIXCHECK recommending a "nearly POSIX" compliant variant
could avoid replacing the glibc code with the gnulib code.
>...
> Or because of security considerations (%n being used to construct "gadgets"
> in malware)?
This, and distributions using several copies of the gnulib code instead
of the fortified and security supported code in glibc.
>...
> --- a/doc/posix-functions/fprintf.texi
> +++ b/doc/posix-functions/fprintf.texi
> @@ -30,6 +30,7 @@ NetBSD 3.0, AIX 5.1, HP-UX 11.23, IRIX 6.5, Solaris 9,
> Cygwin 1.5.x, mingw, MSVC 14.
> @item
> This function does not support the @samp{n} directive on some platforms:
> +glibc when used with @code{_FORTIFY_SOURCE >= 2}
_FORTIFY_SOURCE > 0, the glibc code is under
if ((mode_flags & PRINTF_FORTIFY) != 0)
> (set by default on Ubuntu),
>...
Ubuntu has enabled it by the default in gcc, which means you get it
by default not only for package building.
Debian/Gentoo/Fedora/openSUSE (including RHEL/SLES) all add
_FORTIFY_SOURCE by default at least for building packages,
it might be hard to find a distribution that is not doing
compile time hardening in the year 2020.
cu
Adrian
- gl_{,SN}PRINTF_DIRECTIVE_N wrongly fail on Ubuntu 18.04, Adrian Bunk, 2020/03/08
- Re: gl_{,SN}PRINTF_DIRECTIVE_N wrongly fail on Ubuntu 18.04, Bruno Haible, 2020/03/08
- Re: gl_{,SN}PRINTF_DIRECTIVE_N wrongly fail on Ubuntu 18.04, Adrian Bunk, 2020/03/08
- Re: gl_{,SN}PRINTF_DIRECTIVE_N wrongly fail on Ubuntu 18.04, Bruno Haible, 2020/03/08
- Re: gl_{,SN}PRINTF_DIRECTIVE_N wrongly fail on Ubuntu 18.04,
Adrian Bunk <=
- Re: gl_{,SN}PRINTF_DIRECTIVE_N wrongly fail on Ubuntu 18.04, Bruno Haible, 2020/03/08
- Re: gl_{,SN}PRINTF_DIRECTIVE_N wrongly fail on Ubuntu 18.04, Paul Eggert, 2020/03/08
- Re: gl_{,SN}PRINTF_DIRECTIVE_N wrongly fail on Ubuntu 18.04, Bruno Haible, 2020/03/16