linux-kernel - Re: [PATCH] kbuild: set EXIT trap before creating temporary directory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <YuvwAkqHRk2pbh4f@fjasle.eu>
Date:   Thu, 4 Aug 2022 18:12:50 +0200
From:   Nicolas Schier <nicolas@...sle.eu>
To:     Masahiro Yamada <masahiroy@...nel.org>
Cc:     linux-kbuild@...r.kernel.org,
        David Laight <David.Laight@...lab.com>,
        Michal Marek <michal.lkml@...kovi.net>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] kbuild: set EXIT trap before creating temporary directory

On Thu, Jul 28, 2022 at 12:14:33PM +0900, Masahiro Yamada wrote:
> Swap the order of 'mkdir' and 'trap' just in case the subshell is
> interrupted between 'mkdir' and 'trap' although the effect might be
> subtle.
> 
> Please not this is not a perfect solution to avoid the left-over tmp

not -> note?

> directory. There are more cases that miss to remove the tmp directory,
> for example:
> 
>  - When interrupted, dash does not invoke the EXIT trap (bash does)
> 
>  - 'rm' command might be interrupted before removing the directory
> 
> I am not addressing all the cases since the tmp directory is harmless
> after all.
> 
> Signed-off-by: Masahiro Yamada <masahiroy@...nel.org>
> ---
> 
>  scripts/Kconfig.include   | 2 +-
>  scripts/Makefile.compiler | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)

Do you want to add the same for filechk macro in scripts/Kbuild.include?

Reviewed-by: Nicolas Schier <nicolas@...sle.eu>

Kind regards,
Nicolas

> 
> diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include
> index c1f4222d223d..a0ccceb22cf8 100644
> --- a/scripts/Kconfig.include
> +++ b/scripts/Kconfig.include
> @@ -25,7 +25,7 @@ failure = $(if-success,$(1),n,y)
>  
>  # $(cc-option,<flag>)
>  # Return y if the compiler supports <flag>, n otherwise
> -cc-option = $(success,mkdir .tmp_$$; trap "rm -rf .tmp_$$" EXIT; $(CC) -Werror $(CLANG_FLAGS) $(1) -c -x c /dev/null -o .tmp_$$/tmp.o)
> +cc-option = $(success,trap "rm -rf .tmp_$$" EXIT; mkdir .tmp_$$; $(CC) -Werror $(CLANG_FLAGS) $(1) -c -x c /dev/null -o .tmp_$$/tmp.o)
>  
>  # $(ld-option,<flag>)
>  # Return y if the linker supports <flag>, n otherwise
> diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler
> index 86ecd2ac874c..94d0d40cddb3 100644
> --- a/scripts/Makefile.compiler
> +++ b/scripts/Makefile.compiler
> @@ -21,8 +21,8 @@ TMPOUT = $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_$$$$
>  # automatically cleaned up.
>  try-run = $(shell set -e;		\
>  	TMP=$(TMPOUT)/tmp;		\
> -	mkdir -p $(TMPOUT);		\
>  	trap "rm -rf $(TMPOUT)" EXIT;	\
> +	mkdir -p $(TMPOUT);		\
>  	if ($(1)) >/dev/null 2>&1;	\
>  	then echo "$(2)";		\
>  	else echo "$(3)";		\
> -- 
> 2.34.1

-- 
epost|xmpp: nicolas@...sle.eu          irc://oftc.net/nsc
↳ gpg: 18ed 52db e34f 860e e9fb  c82b 7d97 0932 55a0 ce7f
     -- frykten for herren er opphav til kunnskap --