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Date: Thu, 11 Apr 2024 20:31:42 +0200
From: "Yann E. MORIN" <yann.morin.1998@free.fr>
To: Ben Hutchings <ben.hutchings@mind.be>
Cc: buildroot@buildroot.org, oss-security@lists.openwall.com
Message-ID: <ZhgsjkTpLfChnX_U@landeda>
References: <20240411152016.1185109-1-ben.hutchings@mind.be>
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In-Reply-To: <20240411152016.1185109-1-ben.hutchings@mind.be>
Subject: [oss-security] Re: [Buildroot] [PATCH] package/skeleton-init-sysv: Set sticky bit
 on /dev/shm

Ben, All,

On 2024-04-11 17:20 +0200, Ben Hutchings via buildroot spake thusly:
> /dev/shm is a world-writable directory, like /tmp, and should also
> have the sticky bit set.  Without this, any user can delete and
> replace another user's files in /dev/shm.

Indeed, good catch!

> This bug has been present since /dev/shm was added to the skeleton
> /etc/fstab, but appears to have been fixed for systems using systemd
> by commit 76fc9275f14e "system: separate sysv and systemd parts of the
> skeleton" which went into Buildroot 2017.08.
> 
> Signed-off-by: Ben Hutchings <ben.hutchings@mind.be>
> Fixes: 22fde22e35f98f7830c2f8955465532328348cd1

Applied to master, thanks.

Regards,
Yann E. MORIN.

> ---
>  package/skeleton-init-sysv/skeleton/etc/fstab | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/package/skeleton-init-sysv/skeleton/etc/fstab b/package/skeleton-init-sysv/skeleton/etc/fstab
> index 169054b74f..06c20fe9d5 100644
> --- a/package/skeleton-init-sysv/skeleton/etc/fstab
> +++ b/package/skeleton-init-sysv/skeleton/etc/fstab
> @@ -2,7 +2,7 @@
>  /dev/root	/		ext2	rw,noauto	0	1
>  proc		/proc		proc	defaults	0	0
>  devpts		/dev/pts	devpts	defaults,gid=5,mode=620,ptmxmode=0666	0	0
> -tmpfs		/dev/shm	tmpfs	mode=0777	0	0
> +tmpfs		/dev/shm	tmpfs	mode=1777	0	0
>  tmpfs		/tmp		tmpfs	mode=1777	0	0
>  tmpfs		/run		tmpfs	mode=0755,nosuid,nodev	0	0
>  sysfs		/sys		sysfs	defaults	0	0
> -- 
> 2.39.2
> 
> _______________________________________________
> buildroot mailing list
> buildroot@buildroot.org
> https://lists.buildroot.org/mailman/listinfo/buildroot

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