Re: [PATCH v4] scripts/selinux: modernize mdp

[Dominick Grift <dominick.grift@defensec.nl>]

On Wed, Feb 20, 2019 at 08:43:02PM +0100, Dominick Grift wrote:
> The MDP example no longer works on modern systems.

I would prefer that my changes would just be addressed in Stephen's patch instead.
In that case this patch can be ignored.

> 
> Add support for devtmpfs. This is required by login programs to relabel terminals.
> Compile the policy with deny_unknown allow status to anticipate user space object managers in core components such as systemd.
> Add default seusers mapping and failsafe context for the SELinux PAM module.
> 
> V2:
> Fix existing file test for setfiles.
> Add a file test for checkpolicy similar to the test for setfiles for consistency.
> Execute setfiles with -F to ensure that customizables are relabeled as well in scenarios where filesystems are labeled but where SELinux is disabled.
> 
> V3: Fixes file test that was introduced in V2.
> 
> V4: Remove file tests and instead rely on which
> 
> Signed-off-by: Dominick Grift <dominick.grift@defensec.nl>
> ---
>  scripts/selinux/install_policy.sh | 23 +++++++++++++----------
>  scripts/selinux/mdp/mdp.c         |  1 +
>  2 files changed, 14 insertions(+), 10 deletions(-)
> 
> diff --git a/scripts/selinux/install_policy.sh b/scripts/selinux/install_policy.sh
> index 0b86c47baf7d..773377838670 100755
> --- a/scripts/selinux/install_policy.sh
> +++ b/scripts/selinux/install_policy.sh
> @@ -6,25 +6,28 @@ if [ `id -u` -ne 0 ]; then
>  fi
>  SF=`which setfiles`
>  if [ $? -eq 1 ]; then
> -	if [ -f /sbin/setfiles ]; then
> -		SF="/usr/setfiles"
> -	else
> -		echo "no selinux tools installed: setfiles"
> -		exit 1
> -	fi
> +	echo "no selinux tools installed: setfiles"
> +	exit 1
>  fi
>  
>  cd mdp
>  
>  CP=`which checkpolicy`
> +if [ $? -eq 1 ]; then
> +	echo "no selinux tools installed: checkpolicy"
> +	exit 1
> +fi
>  VERS=`$CP -V | awk '{print $1}'`
>  
>  ./mdp policy.conf file_contexts
> -$CP -o policy.$VERS policy.conf
> +$CP -U allow -o policy.$VERS policy.conf
>  
>  mkdir -p /etc/selinux/dummy/policy
>  mkdir -p /etc/selinux/dummy/contexts/files
>  
> +echo "__default__:user_u" > /etc/selinux/dummy/seusers
> +echo "base_r:base_t" > /etc/selinux/dummy/contexts/failsafe_context
> +
>  cp file_contexts /etc/selinux/dummy/contexts/files
>  cp dbus_contexts /etc/selinux/dummy/contexts
>  cp policy.$VERS /etc/selinux/dummy/policy
> @@ -55,15 +58,15 @@ else
>  fi
>  
>  cd /etc/selinux/dummy/contexts/files
> -$SF file_contexts /
> +$SF -F file_contexts /
>  
>  mounts=`cat /proc/$$/mounts | egrep "ext2|ext3|xfs|jfs|ext4|ext4dev|gfs2" | awk '{ print $2 '}`
> -$SF file_contexts $mounts
> +$SF -F file_contexts $mounts
>  
>  
>  dodev=`cat /proc/$$/mounts | grep "/dev "`
>  if [ "eq$dodev" != "eq" ]; then
>  	mount --move /dev /mnt
> -	$SF file_contexts /dev
> +	$SF -F file_contexts /dev
>  	mount --move /mnt /dev
>  fi
> diff --git a/scripts/selinux/mdp/mdp.c b/scripts/selinux/mdp/mdp.c
> index 073fe7537f6c..cf06d5694cbc 100644
> --- a/scripts/selinux/mdp/mdp.c
> +++ b/scripts/selinux/mdp/mdp.c
> @@ -131,6 +131,7 @@ int main(int argc, char *argv[])
>  
>  	fprintf(fout, "fs_use_trans mqueue user_u:base_r:base_t;\n");
>  	fprintf(fout, "fs_use_trans devpts user_u:base_r:base_t;\n");
> +	fprintf(fout, "fs_use_trans devtmpfs user_u:base_r:base_t;\n");
>  	fprintf(fout, "fs_use_trans hugetlbfs user_u:base_r:base_t;\n");
>  	fprintf(fout, "fs_use_trans tmpfs user_u:base_r:base_t;\n");
>  	fprintf(fout, "fs_use_trans shm user_u:base_r:base_t;\n");
> -- 
> 2.21.0.rc1
> 

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Dominick Grift