Re: [V2 PATCH 1/3] Makefile: fix _FORTIFY_SOURCE redefined build error

From: Jason Zaman <jason@perfinion.com>
To: bill.c.roberts@gmail.com
Cc: selinux@vger.kernel.org, sds@tycho.nsa.gov,
	William Roberts <william.c.roberts@intel.com>
Subject: Re: [V2 PATCH 1/3] Makefile: fix _FORTIFY_SOURCE redefined build error
Date: Thu, 27 Dec 2018 22:29:11 +0800	[thread overview]
Message-ID: <20181227142911.GA14910@baraddur.perfinion.com> (raw)
In-Reply-To: <1545836068-7824-1-git-send-email-william.c.roberts@intel.com>

On Wed, Dec 26, 2018 at 06:54:26AM -0800, bill.c.roberts@gmail.com wrote:
> From: William Roberts <william.c.roberts@intel.com>
> 
> Certain builds of gcc enable _FORTIFY_SOURCE which results in the error:
> <command-line>:0:0: warning: "_FORTIFY_SOURCE" redefined
> <command-line>:0:0: note: this is the location of the previous definition
> 
> Correct this by undefining it first and redefining it. Also, the previous
> command line option was using -Wp which is passing the value *AS IS* to the
> pre-processor rather than to the compiler driver. The C pre-processor has
> an undocumented interface subject to change per man 1 gcc. Just use the
> -D option to specify this value.
> 
> Signed-off-by: William Roberts <william.c.roberts@intel.com>

Acked-by: Jason Zaman <jason@perfinion.com>

The whole series looks good to me, go ahead and apply it. I dont think
the other parts have had _FORTIFY_SOURCE so after next release (probably
too soon to apply it now?) we might want to add these same warnings to
everything else not only libselinux.

-- Jason

> ---
>  libselinux/src/Makefile   | 2 +-
>  libselinux/utils/Makefile | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/libselinux/src/Makefile b/libselinux/src/Makefile
> index 977b5c8cfcca..6263d11393e6 100644
> --- a/libselinux/src/Makefile
> +++ b/libselinux/src/Makefile
> @@ -64,7 +64,7 @@ ifeq ($(COMPILER), gcc)
>  EXTRA_CFLAGS = -fipa-pure-const -Wlogical-op -Wpacked-bitfield-compat -Wsync-nand \
>  	-Wcoverage-mismatch -Wcpp -Wformat-contains-nul -Wnormalized=nfc -Wsuggest-attribute=const \
>  	-Wsuggest-attribute=noreturn -Wsuggest-attribute=pure -Wtrampolines -Wjump-misses-init \
> -	-Wno-suggest-attribute=pure -Wno-suggest-attribute=const -Wp,-D_FORTIFY_SOURCE
> +	-Wno-suggest-attribute=pure -Wno-suggest-attribute=const -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE
>  else
>  EXTRA_CFLAGS = -Wunused-command-line-argument
>  endif
> diff --git a/libselinux/utils/Makefile b/libselinux/utils/Makefile
> index d06ffd66893b..890ff36f3bbc 100644
> --- a/libselinux/utils/Makefile
> +++ b/libselinux/utils/Makefile
> @@ -30,7 +30,7 @@ CFLAGS ?= -O -Wall -W -Wundef -Wformat-y2k -Wformat-security -Winit-self -Wmissi
>            -Wformat-extra-args -Wformat-zero-length -Wformat=2 -Wmultichar \
>            -Woverflow -Wpointer-to-int-cast -Wpragmas \
>            -Wno-missing-field-initializers -Wno-sign-compare \
> -          -Wno-format-nonliteral -Wframe-larger-than=$(MAX_STACK_SIZE) -Wp,-D_FORTIFY_SOURCE \
> +          -Wno-format-nonliteral -Wframe-larger-than=$(MAX_STACK_SIZE) -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE \
>            -fstack-protector-all --param=ssp-buffer-size=4 -fexceptions \
>            -fasynchronous-unwind-tables -fdiagnostics-show-option -funit-at-a-time \
>            -Werror -Wno-aggregate-return -Wno-redundant-decls \
> -- 
> 2.7.4
> 