| Message ID | 1551223620-11586-6-git-send-email-zohar@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | selftests/ima: add kexec and kernel module tests | expand |
On 2/26/19 4:27 PM, Mimi Zohar wrote: > While the appended kernel module signature can be verified, when loading > a kernel module via either the init_module or the finit_module syscall, > verifying the IMA signature requires access to the file descriptor, > which is only available via the finit_module syscall. As "modprobe" > does not provide a flag allowing the syscall - init_module or > finit_module - to be specified, this patch does not load a kernel > module. > > This test simply verifies that on secure boot enabled systems with > "CONFIG_IMA_ARCH_POLICY" configured, that at least an appended kernel > module signature or an IMA signature is required based on the Kconfig > and the runtime IMA policy. > > Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> > --- > tools/testing/selftests/ima/Makefile | 2 +- > tools/testing/selftests/ima/test_kernel_module.sh | 96 +++++++++++++++++++++++ > 2 files changed, 97 insertions(+), 1 deletion(-) > create mode 100755 tools/testing/selftests/ima/test_kernel_module.sh > > diff --git a/tools/testing/selftests/ima/Makefile b/tools/testing/selftests/ima/Makefile > index 049c83c9426c..ef5201ff0bea 100644 > --- a/tools/testing/selftests/ima/Makefile > +++ b/tools/testing/selftests/ima/Makefile > @@ -4,7 +4,7 @@ uname_M := $(shell uname -m 2>/dev/null || echo not) > ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/x86/ -e s/x86_64/x86/) > > ifeq ($(ARCH),x86) > -TEST_PROGS := test_kexec_load.sh test_kexec_file_load.sh > +TEST_PROGS := test_kexec_load.sh test_kexec_file_load.sh test_kernel_module.sh > TEST_FILES := common_lib.sh > > include ../lib.mk > diff --git a/tools/testing/selftests/ima/test_kernel_module.sh b/tools/testing/selftests/ima/test_kernel_module.sh > new file mode 100755 > index 000000000000..4009e1b60b03 > --- /dev/null > +++ b/tools/testing/selftests/ima/test_kernel_module.sh > @@ -0,0 +1,96 @@ > +#!/bin/sh > +# SPDX-License-Identifier: GPL-2.0-or-later Same here # SPDX-License-Identifier: GPL-2.0 > +# > +# On secure boot enabled systems with "CONFIG_IMA_ARCH_POLICY" configured, > +# this test verifies that at least an appended kernel module signature or > +# an IMA signature is required. It does not attempt to load a kernel module. > + > +TEST="KERNEL_MODULE" > +. ./common_lib.sh > + > +trap "{ rm -f $IKCONFIG ; }" EXIT > + > +# Some of the IMA builtin policies may require the kernel modules to > +# be signed, but these policy rules may be replaced with a custom > +# policy. Only CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS persists after > +# loading a custom policy. Check if it is enabled, before reading the > +# IMA runtime sysfs policy file. > +# Return 1 for IMA signature required and 0 for not required. > +is_ima_sig_required() > +{ > + local ret=0 > + > + kconfig_enabled "CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS=y" \ > + "IMA kernel module signature required" > + if [ $? -eq 1 ]; then > + log_info "IMA kernel module signature required" > + return 1 > + fi > + > + # The architecture specific or a custom policy may require the > + # kernel module to be signed. Policy rules are walked sequentially. > + # As a result, a policy rule may be defined, but might not necessarily > + # be used. This test assumes if a policy rule is specified, that is > + # the intent. > + if [ $ima_read_policy -eq 1 ]; then > + check_ima_policy "appraise" "func=MODULE_CHECK" \ > + "appraise_type=imasig" > + ret=$? > + [ $ret -eq 1 ] && log_info "IMA signature required"; > + fi > + return $ret > +} > + > +# loading kernel modules requires root privileges > +if [ $(id -ru) -ne 0 ]; then > + log_skip "requires root privileges" > +fi > + > +# Are appended signatures required? > +if [ -e /sys/module/module/parameters/sig_enforce ]; then > + sig_enforce=$(cat /sys/module/module/parameters/sig_enforce) > + if [ $sig_enforce = "Y" ]; then > + log_pass "appended kernel module signature required" > + fi > +fi > + > +get_secureboot_mode > +if [ $? -eq 0 ]; then > + log_skip "secure boot not enabled" > +fi > + > +# get the kernel config > +get_kconfig > + get_kconfig() will be good candidate as a kselftest common function. Is that possible? > +# Determine which kernel config options are enabled > +kconfig_enabled "CONFIG_IMA_ARCH_POLICY=y" \ > + "architecture specific policy enabled" > +arch_policy=$? > + > +kconfig_enabled "CONFIG_MODULE_SIG=y" \ > + "appended kernel modules signature enabled" > +appended_sig_enabled=$? > + > +kconfig_enabled "CONFIG_IMA_READ_POLICY=y" "reading IMA policy permitted" > +ima_read_policy=$? > + > +is_ima_sig_required > +ima_sig_required=$? > + > +if [ $arch_policy -eq 0 ]; then > + log_skip "architecture specific policy not enabled" > +fi > + > +if [ $appended_sig_enabled -eq 1 ]; then > + log_fail "appended kernel module signature enabled, but not required" > +fi > + > +if [ $ima_sig_required -eq 1 ]; then > + log_pass "IMA kernel module signature required" > +fi > + > +if [ $ima_read_policy -eq 1 ]; then > + log_fail "IMA kernel module signature not required" > +else > + log_skip "reading IMA policy not permitted" > +fi > thanks, -- Shuah
Hi Shuah, > > diff --git a/tools/testing/selftests/ima/test_kernel_module.sh b/tools/testing/selftests/ima/test_kernel_module.sh > > new file mode 100755 > > index 000000000000..4009e1b60b03 > > --- /dev/null > > +++ b/tools/testing/selftests/ima/test_kernel_module.sh > > @@ -0,0 +1,96 @@ > > +#!/bin/sh > > +# SPDX-License-Identifier: GPL-2.0-or-later > > Same here > > # SPDX-License-Identifier: GPL-2.0 Sure, I'll make the change here and in the other places. > > +get_secureboot_mode > > +if [ $? -eq 0 ]; then > > + log_skip "secure boot not enabled" > > +fi > > + > > +# get the kernel config > > +get_kconfig > > + > > get_kconfig() will be good candidate as a kselftest common > function. Is that possible? Sure, where would it go? get_kconfig calls log_skip. I didn't see any common logging functions. Petr suggested defining a set of common logging functions. Did you want to only make "log_skip" a common function or the other logging functions log_pass, log_fail, log_info as well? Thanks, Mimi
Hi Mimi, On 2/27/19 7:14 AM, Mimi Zohar wrote: > Hi Shuah, > >>> diff --git a/tools/testing/selftests/ima/test_kernel_module.sh b/tools/testing/selftests/ima/test_kernel_module.sh >>> new file mode 100755 >>> index 000000000000..4009e1b60b03 >>> --- /dev/null >>> +++ b/tools/testing/selftests/ima/test_kernel_module.sh >>> @@ -0,0 +1,96 @@ >>> +#!/bin/sh >>> +# SPDX-License-Identifier: GPL-2.0-or-later >> >> Same here >> >> # SPDX-License-Identifier: GPL-2.0 > > Sure, I'll make the change here and in the other places. > > Thanks. >>> +get_secureboot_mode >>> +if [ $? -eq 0 ]; then >>> + log_skip "secure boot not enabled" >>> +fi >>> + >>> +# get the kernel config >>> +get_kconfig >>> + >> >> get_kconfig() will be good candidate as a kselftest common >> function. Is that possible? > > Sure, where would it go? get_kconfig calls log_skip. I didn't see > any common logging functions. Petr suggested defining a set of common > logging functions. Did you want to only make "log_skip" a common > function or the other logging functions log_pass, log_fail, log_info > as well? > We can do this as a separate effort in the interest of getting these in the interest of getting these in. We have common functions in ksefltest.h for c and we don't have them for tests scripts. We might be able to collect common routines such as get_kconfig into a common .sh and include in tests. If you have time to do this, that will be great. It can be done as a separate effort. thanks, -- Shuah
> >>> +get_secureboot_mode > >>> +if [ $? -eq 0 ]; then > >>> + log_skip "secure boot not enabled" > >>> +fi > >>> + > >>> +# get the kernel config > >>> +get_kconfig > >>> + > >> > >> get_kconfig() will be good candidate as a kselftest common > >> function. Is that possible? > > > > Sure, where would it go? get_kconfig calls log_skip. I didn't see > > any common logging functions. Petr suggested defining a set of common > > logging functions. Did you want to only make "log_skip" a common > > function or the other logging functions log_pass, log_fail, log_info > > as well? > > > > We can do this as a separate effort in the interest of getting these > in the interest of getting these in. > > We have common functions in ksefltest.h for c and we don't have them > for tests scripts. We might be able to collect common routines such > as get_kconfig into a common .sh and include in tests. If you have time > to do this, that will be great. It can be done as a separate effort. Ok. For now, I'm waiting for some review/ack's. Mimi
Hi Mimi, > While the appended kernel module signature can be verified, when loading > a kernel module via either the init_module or the finit_module syscall, > verifying the IMA signature requires access to the file descriptor, > which is only available via the finit_module syscall. As "modprobe" > does not provide a flag allowing the syscall - init_module or > finit_module - to be specified, this patch does not load a kernel > module. > This test simply verifies that on secure boot enabled systems with > "CONFIG_IMA_ARCH_POLICY" configured, that at least an appended kernel > module signature or an IMA signature is required based on the Kconfig > and the runtime IMA policy. > Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> Reviewed-by: Petr Vorel <pvorel@suse.cz> ... > diff --git a/tools/testing/selftests/ima/test_kernel_module.sh b/tools/testing/selftests/ima/test_kernel_module.sh ... > +# Are appended signatures required? > +if [ -e /sys/module/module/parameters/sig_enforce ]; then > + sig_enforce=$(cat /sys/module/module/parameters/sig_enforce) > + if [ $sig_enforce = "Y" ]; then > + log_pass "appended kernel module signature required" > + fi > +fi Another possible helper [1]: is_enabled() # or sysfs_enabled { [ -f "$1" ] && [ "$(cat $1)" = "Y" -o "$(cat $1)" = "1" ] } is_enabled /sys/module/module/parameters/sig_enforce && \ log_pass "appended kernel module signature required" ... Kind regards, Petr [1] https://github.com/linux-test-project/ltp/blob/master/ver_linux#L30
Hi Shuah, > We can do this as a separate effort in the interest of getting these > in the interest of getting these in. > We have common functions in ksefltest.h for c and we don't have them > for tests scripts. We might be able to collect common routines such > as get_kconfig into a common .sh and include in tests. If you have time > to do this, that will be great. It can be done as a separate effort. Some inspiration, what sort of helpers can be for shell see LTP shell API [1]. These helpers tests help tests to be short, readable and with unified output. (I like library variables [2] which are self describing and making test even shorter), setup and cleanup functions called automatically, ... The same applies for C API [3] (e.g. SAFE_*() helpers for handling errors, ...). I wonder if there is even any interest of having any sort of helpers or even framework for shell, when so far there was nothing. > thanks, > -- Shuah Kind regards, Petr [1] https://github.com/linux-test-project/ltp/wiki/Test-Writing-Guidelines#23-writing-a-testcase-in-shell [2] https://github.com/linux-test-project/ltp/wiki/Test-Writing-Guidelines#232-library-variables [3] https://github.com/linux-test-project/ltp/wiki/Test-Writing-Guidelines#22-writing-a-test-in-c
On Thu, 2019-02-28 at 23:32 +0100, Petr Vorel wrote: > Hi Mimi, > > > While the appended kernel module signature can be verified, when loading > > a kernel module via either the init_module or the finit_module syscall, > > verifying the IMA signature requires access to the file descriptor, > > which is only available via the finit_module syscall. As "modprobe" > > does not provide a flag allowing the syscall - init_module or > > finit_module - to be specified, this patch does not load a kernel > > module. > > > This test simply verifies that on secure boot enabled systems with > > "CONFIG_IMA_ARCH_POLICY" configured, that at least an appended kernel > > module signature or an IMA signature is required based on the Kconfig > > and the runtime IMA policy. > > > Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> > Reviewed-by: Petr Vorel <pvorel@suse.cz> > > ... > > diff --git a/tools/testing/selftests/ima/test_kernel_module.sh b/tools/testing/selftests/ima/test_kernel_module.sh > ... > > +# Are appended signatures required? > > +if [ -e /sys/module/module/parameters/sig_enforce ]; then > > + sig_enforce=$(cat /sys/module/module/parameters/sig_enforce) > > + if [ $sig_enforce = "Y" ]; then > > + log_pass "appended kernel module signature required" > > + fi > > +fi > Another possible helper [1]: > is_enabled() # or sysfs_enabled > { > [ -f "$1" ] && [ "$(cat $1)" = "Y" -o "$(cat $1)" = "1" ] > } > > is_enabled /sys/module/module/parameters/sig_enforce && > log_pass "appended kernel module signature required" > Agreed. As this is being used only here in the IMA selftests, deferring making this change until there is a generic common library. Mimi
diff --git a/tools/testing/selftests/ima/Makefile b/tools/testing/selftests/ima/Makefile index 049c83c9426c..ef5201ff0bea 100644 --- a/tools/testing/selftests/ima/Makefile +++ b/tools/testing/selftests/ima/Makefile @@ -4,7 +4,7 @@ uname_M := $(shell uname -m 2>/dev/null || echo not) ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/x86/ -e s/x86_64/x86/) ifeq ($(ARCH),x86) -TEST_PROGS := test_kexec_load.sh test_kexec_file_load.sh +TEST_PROGS := test_kexec_load.sh test_kexec_file_load.sh test_kernel_module.sh TEST_FILES := common_lib.sh include ../lib.mk diff --git a/tools/testing/selftests/ima/test_kernel_module.sh b/tools/testing/selftests/ima/test_kernel_module.sh new file mode 100755 index 000000000000..4009e1b60b03 --- /dev/null +++ b/tools/testing/selftests/ima/test_kernel_module.sh @@ -0,0 +1,96 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-or-later +# +# On secure boot enabled systems with "CONFIG_IMA_ARCH_POLICY" configured, +# this test verifies that at least an appended kernel module signature or +# an IMA signature is required. It does not attempt to load a kernel module. + +TEST="KERNEL_MODULE" +. ./common_lib.sh + +trap "{ rm -f $IKCONFIG ; }" EXIT + +# Some of the IMA builtin policies may require the kernel modules to +# be signed, but these policy rules may be replaced with a custom +# policy. Only CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS persists after +# loading a custom policy. Check if it is enabled, before reading the +# IMA runtime sysfs policy file. +# Return 1 for IMA signature required and 0 for not required. +is_ima_sig_required() +{ + local ret=0 + + kconfig_enabled "CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS=y" \ + "IMA kernel module signature required" + if [ $? -eq 1 ]; then + log_info "IMA kernel module signature required" + return 1 + fi + + # The architecture specific or a custom policy may require the + # kernel module to be signed. Policy rules are walked sequentially. + # As a result, a policy rule may be defined, but might not necessarily + # be used. This test assumes if a policy rule is specified, that is + # the intent. + if [ $ima_read_policy -eq 1 ]; then + check_ima_policy "appraise" "func=MODULE_CHECK" \ + "appraise_type=imasig" + ret=$? + [ $ret -eq 1 ] && log_info "IMA signature required"; + fi + return $ret +} + +# loading kernel modules requires root privileges +if [ $(id -ru) -ne 0 ]; then + log_skip "requires root privileges" +fi + +# Are appended signatures required? +if [ -e /sys/module/module/parameters/sig_enforce ]; then + sig_enforce=$(cat /sys/module/module/parameters/sig_enforce) + if [ $sig_enforce = "Y" ]; then + log_pass "appended kernel module signature required" + fi +fi + +get_secureboot_mode +if [ $? -eq 0 ]; then + log_skip "secure boot not enabled" +fi + +# get the kernel config +get_kconfig + +# Determine which kernel config options are enabled +kconfig_enabled "CONFIG_IMA_ARCH_POLICY=y" \ + "architecture specific policy enabled" +arch_policy=$? + +kconfig_enabled "CONFIG_MODULE_SIG=y" \ + "appended kernel modules signature enabled" +appended_sig_enabled=$? + +kconfig_enabled "CONFIG_IMA_READ_POLICY=y" "reading IMA policy permitted" +ima_read_policy=$? + +is_ima_sig_required +ima_sig_required=$? + +if [ $arch_policy -eq 0 ]; then + log_skip "architecture specific policy not enabled" +fi + +if [ $appended_sig_enabled -eq 1 ]; then + log_fail "appended kernel module signature enabled, but not required" +fi + +if [ $ima_sig_required -eq 1 ]; then + log_pass "IMA kernel module signature required" +fi + +if [ $ima_read_policy -eq 1 ]; then + log_fail "IMA kernel module signature not required" +else + log_skip "reading IMA policy not permitted" +fi
While the appended kernel module signature can be verified, when loading a kernel module via either the init_module or the finit_module syscall, verifying the IMA signature requires access to the file descriptor, which is only available via the finit_module syscall. As "modprobe" does not provide a flag allowing the syscall - init_module or finit_module - to be specified, this patch does not load a kernel module. This test simply verifies that on secure boot enabled systems with "CONFIG_IMA_ARCH_POLICY" configured, that at least an appended kernel module signature or an IMA signature is required based on the Kconfig and the runtime IMA policy. Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> --- tools/testing/selftests/ima/Makefile | 2 +- tools/testing/selftests/ima/test_kernel_module.sh | 96 +++++++++++++++++++++++ 2 files changed, 97 insertions(+), 1 deletion(-) create mode 100755 tools/testing/selftests/ima/test_kernel_module.sh