[LTP] [PATCH 3/3] ima: Add overlay test

[Ignaz Forster]

Hi Petr,

thanks a lot for the LTP integration!

Am 27.03.19 um 17:16 Uhr schrieb Petr Vorel:
> Based on reproducer made by Ignaz Forster <iforster@suse.de>
> used for his not upstreamed patchset [1] and previous report [2].

Just for clarification, as the test is only referring to IMA: With IMA 
everything should be working already, the problem during copy_up 
operations was fixed by Mimi and Goldwyn in 
https://patchwork.kernel.org/patch/10776231/.
As expected the test passes on my IMA-only setup.

My outstanding patchset is only necessary when combining IMA with EVM - 
in this case the test will still fail. I hope I'll be able to resume my 
work in the next few weeks.

The test itself is looking good and working as expected.

> NOTE: backup variables are needed because ima_setup.sh calling
> tst_mount as well when TMPDIR is on tmpfs device.
> 
> [1] https://www.spinics.net/lists/linux-integrity/msg05926.html
> [2] https://www.spinics.net/lists/linux-integrity/msg03593.html
> 
> Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
> Cc: Ignaz Forster <iforster@suse.de>
> Cc: Fabian Vogt <FVogt@suse.com>
> Cc: Weihua Du <WHDu@suse.com>
> Cc: linux-integrity@vger.kernel.org
> Signed-off-by: Petr Vorel <pvorel@suse.cz>

Tested-by: Ignaz Forster <iforster@suse.de>

> ---
>   runtest/ima                                   |  1 +
>   .../integrity/ima/tests/ima_overlay.sh        | 65 +++++++++++++++++++
>   .../security/integrity/ima/tests/ima_setup.sh |  4 +-
>   3 files changed, 68 insertions(+), 2 deletions(-)
>   create mode 100755 testcases/kernel/security/integrity/ima/tests/ima_overlay.sh
> 
> diff --git a/runtest/ima b/runtest/ima
> index bcae16bb7..f96711a7d 100644
> --- a/runtest/ima
> +++ b/runtest/ima
> @@ -3,3 +3,4 @@ ima_measurements ima_measurements.sh
>   ima_policy ima_policy.sh
>   ima_tpm ima_tpm.sh
>   ima_violations ima_violations.sh
> +ima_overlay ima_overlay.sh
> diff --git a/testcases/kernel/security/integrity/ima/tests/ima_overlay.sh b/testcases/kernel/security/integrity/ima/tests/ima_overlay.sh
> new file mode 100755
> index 000000000..eedcd3753
> --- /dev/null
> +++ b/testcases/kernel/security/integrity/ima/tests/ima_overlay.sh
> @@ -0,0 +1,65 @@
> +#!/bin/sh
> +# Copyright (c) 2019 Petr Vorel <pvorel@suse.cz>
> +# Based on reproducer made by Ignaz Forster <iforster@suse.de>
> +
> +TST_SETUP="setup"
> +TST_CLEANUP="cleanup"
> +. ima_setup.sh
> +TST_TESTFUNC="do_test"
> +
> +setup()
> +{
> +	lower="$TST_MNTPOINT/lower"
> +	upper="$TST_MNTPOINT/upper"
> +	work="$TST_MNTPOINT/work"
> +	merged="$TST_MNTPOINT/merged"
> +	mkdir -p $lower $upper $work $merged
> +
> +	device_backup="$TST_DEVICE"
> +	TST_DEVICE="overlay"
> +
> +	fs_type_backup="$TST_FS_TYPE"
> +	TST_FS_TYPE="overlay"
> +
> +	mntpoint_backup="$TST_MNTPOINT"
> +	TST_MNTPOINT="$merged"
> +
> +	params_backup="$TST_MNT_PARAMS"
> +	TST_MNT_PARAMS="-o lowerdir=$lower,upperdir=$upper,workdir=$work"
> +
> +	grep -q ima_appraise_tcb /proc/cmdline || \
> +		tst_brk TCONF "Test requires ima_appraise_tcb kernel parameter"
> +}
> +
> +do_test()
> +{
> +	local file="foo.txt"
> +	local f
> +
> +	tst_mount
> +	mounted=1
> +
> +	ROD echo lower \> $lower/$file
> +	if ! echo overlay > $merged/$file 2>/dev/null; then
> +		tst_res TFAIL "Cannot write to merged layer"
> +		return
> +	fi

I can think of two additional tests here:
1. Appending to a file (>> instead of >)
2. Creating a new file in the overlay

These cases are using different code paths and may fail independently, 
so separate tests would be handy.

Ignaz

> +	for f in $(find $TST_MNTPOINT -type f); do
> +		EXPECT_PASS cat $f \> /dev/null 2\> /dev/null
> +	done
> +}
> +
> +cleanup()
> +{
> +	[ -n "$mounted" ] || return 0
> +
> +	tst_umount $TST_DEVICE
> +
> +	TST_DEVICE="$device_backup"
> +	TST_FS_TYPE="$fs_type_backup"
> +	TST_MNTPOINT="$mntpoint_backup"
> +	TST_MNT_PARAMS="$params_backup"
> +}
> +
> +tst_run
> diff --git a/testcases/kernel/security/integrity/ima/tests/ima_setup.sh b/testcases/kernel/security/integrity/ima/tests/ima_setup.sh
> index da49eb1b2..08aa5300a 100644
> --- a/testcases/kernel/security/integrity/ima/tests/ima_setup.sh
> +++ b/testcases/kernel/security/integrity/ima/tests/ima_setup.sh
> @@ -64,14 +64,14 @@ print_ima_config()
>   	local config="/boot/config-$(uname -r)"
>   	local i
>   
> -	tst_res TINFO "/proc/cmdline: $(cat /proc/cmdline)"
> -
>   	if [ -r "$config" ]; then
>   		tst_res TINFO "IMA kernel config:"
>   		for i in $(grep ^CONFIG_IMA $config); do
>   			tst_res TINFO "$i"
>   		done
>   	fi
> +
> +	tst_res TINFO "/proc/cmdline: $(cat /proc/cmdline)"
>   }
>   
>   ima_setup()
>