[LTP] [PATCH] fs/binfmt_misc01.sh: Add new test for invalid inputs

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
> Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
> ---
>  runtest/fs                                         |  2 +
>  testcases/kernel/fs/binfmt_misc/Makefile           | 12 ++++
>  testcases/kernel/fs/binfmt_misc/binfmt_misc01.sh   | 65 ++++++++++++++++++++++
>  testcases/kernel/fs/binfmt_misc/binfmt_misc_lib.sh | 64 +++++++++++++++++++++
>  4 files changed, 143 insertions(+)
>  create mode 100644 testcases/kernel/fs/binfmt_misc/Makefile
>  create mode 100755 testcases/kernel/fs/binfmt_misc/binfmt_misc01.sh
>  create mode 100755 testcases/kernel/fs/binfmt_misc/binfmt_misc_lib.sh
> 
> diff --git a/runtest/fs b/runtest/fs
> index aca7e35..227c186 100644
> --- a/runtest/fs
> +++ b/runtest/fs
> @@ -82,3 +82,5 @@ quota_remount_test01 quota_remount_test01.sh
>  isofs isofs.sh
>  
>  fs_fill fs_fill
> +
> +binfmt_misc01 binfmt_misc01.sh
> diff --git a/testcases/kernel/fs/binfmt_misc/Makefile b/testcases/kernel/fs/binfmt_misc/Makefile
> new file mode 100644
> index 0000000..f9819ad
> --- /dev/null
> +++ b/testcases/kernel/fs/binfmt_misc/Makefile
> @@ -0,0 +1,12 @@
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +#
> +# Copyright (c) 2019 FUJITSU LIMITED. All rights reserved.
> +# Author: Xiao Yang <yangx.jy@cn.fujitsu.com>
> +
> +top_srcdir              ?= ../../../..
> +
> +include $(top_srcdir)/include/mk/env_pre.mk
> +
> +INSTALL_TARGETS         := binfmt_misc01.sh binfmt_misc_lib.sh
> +
> +include $(top_srcdir)/include/mk/generic_leaf_target.mk
> diff --git a/testcases/kernel/fs/binfmt_misc/binfmt_misc01.sh b/testcases/kernel/fs/binfmt_misc/binfmt_misc01.sh
> new file mode 100755
> index 0000000..1e9e9b9
> --- /dev/null
> +++ b/testcases/kernel/fs/binfmt_misc/binfmt_misc01.sh
> @@ -0,0 +1,65 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +#
> +# Copyright (c) 2019 FUJITSU LIMITED. All rights reserved.
> +# Author: Xiao Yang <yangx.jy@cn.fujitsu.com>
> +#
> +# Description:
> +# Use various invalid inputs to register a new binary type.
> +# 1) Invalid format of string fails to register a new binary type.
> +# 2) Invalid type fails to register a new binary type.
> +# 3) Invalid name containing slashes fails to register a new
> +#    binary type.
> +# 4) If extension matching is chosen, invalid magic containing
> +#    slashes fails to register a new binary type.
> +# 5) If magic matching is chosen, invalid offset(e.g. -1 and
> +#    2500000000) fails to register a new binary type.
> +# 6) Invalid flag fails to register a new binary type.
> +#
> +# Note:
> +# This is also a regression test for the following kernel bug:
> +# '5cc41e099504 ("fs/binfmt_misc.c: do not allow offset overflow")'
> +
> +
> +TST_CNT=9
> +TST_TESTFUNC=do_test
> +TST_NEEDS_CMDS="cat"

TST_NEEDS_ROOT=1 ?

> +. binfmt_misc_lib.sh
> +
> +verify_binfmt_misc()
> +{
> +	local name=$(echo "$1" | awk -F ':' '{print $2}')
> +	local mntpoint=$(get_binfmt_misc_mntpoint)
> +
> +	(echo "$1" >"$mntpoint/register") 2>/dev/null

We should check the return value here as well, it should be non-zero.

> +	if [ ! -f "$mntpoint/$name" ]; then
> +		tst_res TPASS "Failed to register a binary type"
> +		return
> +	fi
> +
> +	# Trigger kernel crash reliably by cat command.
> +	cat "$mntpoint/$name" >/dev/null
> +	tst_res TFAIL "Register a binary type successfully"
> +
> +	(echo -1 >"$mntpoint/$name") 2>/dev/null

Here as well, we should check the return value.

> +	[ -f "$mntpoint/$name" ] && \
> +		tst_res TWARN "Failed to remove a binary type"
> +}
> +
> +do_test()
> +{
> +	case $1 in
> +	1) verify_binfmt_misc ".textension,E,,ltp,,$(which cat),";;
> +	2) verify_binfmt_misc ":tnone:X::ltp::$(which cat):";;
> +	3) verify_binfmt_misc ":textension/:E::ltp::$(which cat):";;
> +	4) verify_binfmt_misc ":tmagic/:M::ltp::$(which cat):";;
> +	5) verify_binfmt_misc ":textension:E::ltp/::$(which cat):";;
> +	6) verify_binfmt_misc ":tmagic:M:-1:ltp::$(which cat):";;
> +	7) verify_binfmt_misc ":tmagic:M:2500000000:ltp::$(which cat):";;
> +	8) verify_binfmt_misc ":textension:E::ltp::$(which cat):A";;
> +	9) verify_binfmt_misc ":tmagic:M::ltp::$(which cat):A";;
> +	esac
> +}
> +
> +tst_run
> diff --git a/testcases/kernel/fs/binfmt_misc/binfmt_misc_lib.sh b/testcases/kernel/fs/binfmt_misc/binfmt_misc_lib.sh
> new file mode 100755
> index 0000000..d188601
> --- /dev/null
> +++ b/testcases/kernel/fs/binfmt_misc/binfmt_misc_lib.sh
> @@ -0,0 +1,64 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +#
> +# Copyright (c) 2019 FUJITSU LIMITED. All rights reserved.
> +# Author: Xiao Yang <yangx.jy@cn.fujitsu.com>
> +
> +TST_SETUP=binfmt_misc_setup
> +TST_CLEANUP=binfmt_misc_cleanup
> +TST_NEEDS_DRIVERS="binfmt_misc"
> +TST_NEEDS_TMPDIR=1
> +TST_NEEDS_CMDS="${TST_NEEDS_CMDS} modprobe mount umount mkdir rm"
> +
> +. tst_test.sh
> +
> +rmod_binfmt_misc=0
> +umount_binfmt_misc=0
> +binfmt_misc_mntpoint="ltp_binfmt_misc"
> +
> +get_binfmt_misc_mntpoint()
> +{
> +	local mntpoint
> +
> +	mntpoint=$(grep " binfmt_misc " /proc/mounts | awk '{ print $2 }')
> +	[ -z "$mntpoint" ] && tst_brk TBROK "Can't get binfmt_misc mntpoint"
> +
> +	echo "$mntpoint"
> +}
> +
> +binfmt_misc_setup()
> +{
> +	local mntpoint
> +
> +	if ! grep -q "binfmt_misc" /proc/filesystems; then
> +		ROD modprobe binfmt_misc
> +		rmod_binfmt_misc=1
> +	fi
> +
> +	# Match fs type accurately, because autofs is also mounted on
> +	# /proc/sys/fs/binfmt_misc on some distros, as below:
> +	# cat /proc/mounts | grep binfmt_misc
> +	# systemd-1 /proc/sys/fs/binfmt_misc autofs ...
> +	# binfmt_misc /proc/sys/fs/binfmt_misc binfmt_misc ...
> +	mntpoint=$(grep " binfmt_misc " /proc/mounts | awk '{ print $2 }')

You can do just: awk '/binfmt_misc/ { print $2 }' /proc/mounts

> +	[ -n "$mntpoint" ] && return
> +
> +	ROD mkdir ${binfmt_misc_mntpoint}
> +	ROD mount -t binfmt_misc none ${binfmt_misc_mntpoint}
> +	umount_binfmt_misc=1
> +}
> +
> +binfmt_misc_cleanup()
> +{
> +	if [ ${umount_binfmt_misc} -ne 0 ]; then
> +		umount ${binfmt_misc_mntpoint}
> +		umount_binfmt_misc=0
> +	fi
> +
> +	[ -d ${binfmt_misc_mntpoint} ] && rm -rf ${binfmt_misc_mntpoint}
> +
> +	if [ ${rmod_binfmt_misc} -ne 0 ]; then
> +		modprobe -r binfmt_misc
> +		rmod_binfmt_misc=0
> +	fi
> +}

Other than the minor things it looks fine.

Also it would be nice to have functional test as well, I guess that we
can register /bin/sh to be interpreter for a file with specific magic
and extension then execute a script that does just echo test or
something like this.

-- 
Cyril Hrubis
chrubis@suse.cz