[LTP] [PATCH 3/3] IMA: Add a test to verify measurement of certificate imported into a keyring

[Lachlan Sneff]

The IMA subsystem supports measuring certificates that have been
imported into either system built-in or user-defined keyrings.
A test to verify measurement of a certificate imported
into a keyring is required.

Add an IMA measurement test that verifies that an x509 certificate
can be imported into a newly-created, user-defined keyring and measured
correctly by the IMA subsystem.

A certificate used by the test is included in the `datafiles/keys`
directory.

There can be restrictions on importing a certificate into a builtin
trusted keyring. For example, the `.ima` keyring requires that
imported certs be signed by a kernel private key in certain
kernel configurations. For this reason, this test defines
a user-defined keyring and imports a certificate into that.

Signed-off-by: Lachlan Sneff <t-josne@linux.microsoft.com>
---
 .../kernel/security/integrity/ima/README.md   |  14 ++++++
 .../security/integrity/ima/datafiles/Makefile |   2 +-
 .../integrity/ima/datafiles/keys/Makefile     |  15 ++++++
 .../integrity/ima/datafiles/keys/x509_ima.der | Bin 0 -> 650 bytes
 .../security/integrity/ima/tests/ima_keys.sh  |  44 +++++++++++++++++-
 5 files changed, 72 insertions(+), 3 deletions(-)
 create mode 100644 testcases/kernel/security/integrity/ima/datafiles/keys/Makefile
 create mode 100644 testcases/kernel/security/integrity/ima/datafiles/keys/x509_ima.der

diff --git a/testcases/kernel/security/integrity/ima/README.md b/testcases/kernel/security/integrity/ima/README.md
index 2956ac7fd..bfa015191 100644
--- a/testcases/kernel/security/integrity/ima/README.md
+++ b/testcases/kernel/security/integrity/ima/README.md
@@ -23,6 +23,20 @@ Mandatory kernel configuration for IMA:
 ```
 CONFIG_IMA_READ_POLICY=y
 ```
+The certificate import test in `ima_keys.sh` also requires that
+the `key_import_test` keyring is specified in the IMA policy.
+
+One way to do this is to modify an existing KEY_CHECK entry
+in the IMA policy by adding `key_import_test` for keyrings:
+```
+measure func=KEY_CHECK keyrings=.ima|.evm|key_import_test template=ima-buf
+```
+
+If KEY_CHECK entry does not exist in the IMA policy then by adding
+the following line:
+```
+measure func=KEY_CHECK keyrings=key_import_test template=ima-buf
+```
 
 ### IMA kexec test
 
diff --git a/testcases/kernel/security/integrity/ima/datafiles/Makefile b/testcases/kernel/security/integrity/ima/datafiles/Makefile
index 3772e9a03..4b4c46b82 100644
--- a/testcases/kernel/security/integrity/ima/datafiles/Makefile
+++ b/testcases/kernel/security/integrity/ima/datafiles/Makefile
@@ -24,6 +24,6 @@ top_srcdir		?= ../../../../../..
 
 include	$(top_srcdir)/include/mk/env_pre.mk
 
-SUBDIRS			:= policy
+SUBDIRS			:= policy keys
 
 include $(top_srcdir)/include/mk/generic_trunk_target.mk
diff --git a/testcases/kernel/security/integrity/ima/datafiles/keys/Makefile b/testcases/kernel/security/integrity/ima/datafiles/keys/Makefile
new file mode 100644
index 000000000..a8ab7a1b5
--- /dev/null
+++ b/testcases/kernel/security/integrity/ima/datafiles/keys/Makefile
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (c) 2020 Microsoft Corporation
+# Author: Lachlan Sneff <t-josne@linux.microsoft.com>
+#
+# IMA datafiles/keys Makefile
+
+top_srcdir		?= ../../../../../../..
+
+include	$(top_srcdir)/include/mk/env_pre.mk
+
+INSTALL_DIR		:= testcases/data/ima_keys
+
+INSTALL_TARGETS		:= x509_ima.der
+
+include $(top_srcdir)/include/mk/generic_leaf_target.mk
diff --git a/testcases/kernel/security/integrity/ima/datafiles/keys/x509_ima.der b/testcases/kernel/security/integrity/ima/datafiles/keys/x509_ima.der
new file mode 100644
index 0000000000000000000000000000000000000000..92be058da22adffa9d6b6e51efa0c737ebbbbdcd
GIT binary patch
literal 650
zcmXqLVrnyJVtl`VnTe5!NhJD#vj69`9|BBf8}FEsx@^_9$Clp>c-c6$+C196^D;7W
zvoaV27z!HjvoVLVaPe?t<QJFZCFZ6YN*hRmgqV4R$}{p4b2Al+Gt=`j^U@WvQ!5SS
z3}oO&a59SVLzFncG#ki?^BP(jSQr@@7#Ud_7)6Qm8W{k&hEOgIY;2s5>?=lA2Ij_I
z27|^<rp88wchfeduxmMW^j9qUxkIugeev4q7u7yrJR_rW$*!>VOo=tim8DK0r^FsU
zl)K`}`+CO4@4KBkoLmcj?fH`%wbDvU<d=4Z>6-SMf6Eh}{&)1rdsOoNQ-1fgBQ1t{
zVTqGwuK95LlFE)6i{@=vlP6!2`Y}x<BF&oXU_nlDxy@C+CNp&=W=00a#jys_20XwZ
zl@(@W{LjK<z+k`);_<VvFf*|?7|4P+d@N!tBCNWX-0#?!UAx9s`mgFmW+nI2#6kmk
zkhC(3gn?Lt$m4W@56wQ)?QVKW<nOtpT)HJrB?Q^`z&K?FdV8b(y8m)~mOOvswu^9m
z-o7mOwCAzaT*~`Y4wxFtmNA_89`W;j{r#iww*5OC5vgEziqD_%=ki$*`;s}`Pfwi{
zbotZ0X`ckHOmaVLm85n@E9hN_K;~PUB>DFAzh(;(UoMln9V>g;W#-LUGS7A`nYQKY
WBem{7L5JThS+;$vggi%(*E;~nlJ80Y

literal 0
HcmV?d00001

diff --git a/testcases/kernel/security/integrity/ima/tests/ima_keys.sh b/testcases/kernel/security/integrity/ima/tests/ima_keys.sh
index 3aea26056..f34f40132 100755
--- a/testcases/kernel/security/integrity/ima/tests/ima_keys.sh
+++ b/testcases/kernel/security/integrity/ima/tests/ima_keys.sh
@@ -6,9 +6,10 @@
 #
 # Verify that keys are measured correctly based on policy.
 
-TST_NEEDS_CMDS="cut grep sed tr xxd"
-TST_CNT=1
+TST_NEEDS_CMDS="grep cut sed tr xxd evmctl openssl keyctl"
+TST_CNT=2
 TST_NEEDS_DEVICE=1
+TST_NEEDS_ROOT=1
 
 . ima_setup.sh
 
@@ -58,4 +59,43 @@ test1()
 	tst_res TPASS "specified keyrings were measured correctly"
 }
 
+# Create a new keyring, import a certificate into it, and verify
+# that the certificate is measured correctly by IMA.
+test2() {
+	local new_keyring_id temp_file="file.txt" \
+		cert_file="$TST_DATAROOT/x509_ima.der"
+
+	if ! check_ima_policy_content '^measure.*func=KEY_CHECK.*keyrings=.*key_import_test'; then
+		tst_brk TCONF "the IMA policy does not include the key_import_test keyring. See the LTP IMA README."
+	fi
+
+	# Assuming this test is executed in a separate shell,
+	# create a new session that will be cleaned up when
+	# the shell exits.
+	keyctl new_session > /dev/null
+
+	new_keyring_id=$(keyctl newring key_import_test @s) || \
+		tst_brk TCONF "unable to create a new keyring"
+
+	tst_is_num "$new_keyring_id" || \
+		tst_brk TCONF "unable to parse the new keyring id"
+
+	evmctl import "$cert_file" "$new_keyring_id" > /dev/null || \
+		tst_brk TCONF "unable to import a cert into a the key_import_test keyring"
+
+	grep "key_import_test" "$ASCII_MEASUREMENTS" | tail -n1 | cut -d' ' -f6 | \
+		xxd -r -p > "$temp_file" || \
+		tst_brk TCONF "keyring not found in $ASCII_MEASUREMENTS"
+
+	if ! openssl x509 -in "$temp_file" -inform der > /dev/null; then
+		tst_brk TCONF "the cert logged in $ASCII_MEASUREMENTS is not a valid x509 certificate"
+	fi
+
+	if cmp -s "$temp_file" "$cert_file"; then
+		tst_res TPASS "logged cert matches original cert"
+	else
+		tst_res TFAIL "logged cert does not match original cert"
+	fi
+}
+
 tst_run
-- 
2.25.1