[LTP] [PATCH v2 3/4] IMA: Add a test to verify measurement of certificate imported into a keyring

Petr Vorel pvorel@suse.cz
Fri Aug 7 22:46:51 CEST 2020


From: Lachlan Sneff <t-josne@linux.microsoft.com>

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.

Reviewed-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Lachlan Sneff <t-josne@linux.microsoft.com>
[ pvorel: Added key_import_test into keycheck.policy, reword
instructions in README.md, LTP API related fixes ]
Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
I did various changes:
* fix error check in pipe command (grep $keyring_name
  $ASCII_MEASUREMENTS ...) $? contains exit code just of last command
  (xxd) => check for empty file.
* use more propriate error flags (TCONF => TFAIL, but some of them could
  be also TBROK)
* tst_brk => tst_res && return in test1 (to give chance test2 to be run)
* add TINFO message about test
* remove obvious comment

Kind regards,
Petr

 .../kernel/security/integrity/ima/README.md   |  12 ++--
 .../ima/datafiles/ima_keys/keycheck.policy    |   2 +-
 .../ima/datafiles/ima_keys/x509_ima.der       | Bin 0 -> 650 bytes
 .../security/integrity/ima/tests/ima_keys.sh  |  68 +++++++++++++++---
 4 files changed, 69 insertions(+), 13 deletions(-)
 create mode 100644 testcases/kernel/security/integrity/ima/datafiles/ima_keys/x509_ima.der

diff --git a/testcases/kernel/security/integrity/ima/README.md b/testcases/kernel/security/integrity/ima/README.md
index 392e1e868..68d046678 100644
--- a/testcases/kernel/security/integrity/ima/README.md
+++ b/testcases/kernel/security/integrity/ima/README.md
@@ -16,11 +16,15 @@ space, may contain equivalent measurement tcb rules, detecting them would
 require `IMA_READ_POLICY=y` therefore ignore this option.
 
 ### IMA key test
-`ima_keys.sh` requires a readable IMA policy, as well as a loaded policy
-with `func=KEY_CHECK keyrings=...`, see example in `keycheck.policy`.
+The measuring keys test (first test) in `ima_keys.sh` requires a readable IMA
+policy, as well as a loaded measure policy with `func=KEY_CHECK keyrings=...`.
 
-As well as what's required for the IMA tests, the following are also required
--in the kernel configuration:
+The certificate import test (second test) require measure policy with
+`func=KEY_CHECK keyrings=key_import_test`. Valid policy for both is in
+`keycheck.policy`.
+
+As well as what's required for the IMA tests, key tests require reading the IMA
+policy allowed in the kernel configuration:
 ```
 CONFIG_IMA_READ_POLICY=y
 ```
diff --git a/testcases/kernel/security/integrity/ima/datafiles/ima_keys/keycheck.policy b/testcases/kernel/security/integrity/ima/datafiles/ima_keys/keycheck.policy
index 3f1934a3d..623162002 100644
--- a/testcases/kernel/security/integrity/ima/datafiles/ima_keys/keycheck.policy
+++ b/testcases/kernel/security/integrity/ima/datafiles/ima_keys/keycheck.policy
@@ -1 +1 @@
-measure func=KEY_CHECK keyrings=.ima|.evm|.builtin_trusted_keys|.blacklist template=ima-buf
+measure func=KEY_CHECK keyrings=.ima|.evm|.builtin_trusted_keys|.blacklist|key_import_test template=ima-buf
diff --git a/testcases/kernel/security/integrity/ima/datafiles/ima_keys/x509_ima.der b/testcases/kernel/security/integrity/ima/datafiles/ima_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 53c289054..30950904e 100755
--- a/testcases/kernel/security/integrity/ima/tests/ima_keys.sh
+++ b/testcases/kernel/security/integrity/ima/tests/ima_keys.sh
@@ -6,8 +6,8 @@
 #
 # Verify that keys are measured correctly based on policy.
 
-TST_NEEDS_CMDS="cut grep sed tr xxd"
-TST_CNT=1
+TST_NEEDS_CMDS="cmp cut grep sed tr xxd"
+TST_CNT=2
 TST_NEEDS_DEVICE=1
 
 . ima_setup.sh
@@ -20,20 +20,22 @@ test1()
 	local pattern="func=KEY_CHECK"
 	local test_file="file.txt"
 
-	tst_res TINFO "verifying key measurement for keyrings and templates specified in IMA policy file"
+	tst_res TINFO "verify key measurement for keyrings and templates specified in IMA policy"
 
 	require_ima_policy_content "$pattern"
 	keycheck_lines=$(check_ima_policy_content "$pattern" "")
 	keycheck_line=$(echo "$keycheck_lines" | grep "keyrings" | head -n1)
 
 	if [ -z "$keycheck_line" ]; then
-		tst_brk TCONF "ima policy does not specify a keyrings to check"
+		tst_res TCONF "IMA policy does not specify a keyrings to check"
+		return
 	fi
 
 	keyrings=$(echo "$keycheck_line" | tr " " "\n" | grep "keyrings" | \
 		sed "s/\./\\\./g" | cut -d'=' -f2)
 	if [ -z "$keyrings" ]; then
-		tst_brk TCONF "ima policy has a keyring key-value specifier, but no specified keyrings"
+		tst_res TCONF "IMA policy has a keyring key-value specifier, but no specified keyrings"
+		return
 	fi
 
 	templates=$(echo "$keycheck_line" | tr " " "\n" | grep "template" | \
@@ -49,11 +51,13 @@ test1()
 
 		echo "$line" | cut -d' ' -f6 | xxd -r -p > $test_file
 
-		expected_digest="$(compute_digest $algorithm $test_file)" || \
-			tst_brk TCONF "cannot compute digest for $algorithm"
+		if ! expected_digest="$(compute_digest $algorithm $test_file)"; then
+			tst_res TCONF "cannot compute digest for $algorithm"
+			return
+		fi
 
 		if [ "$digest" != "$expected_digest" ]; then
-			tst_res TFAIL "incorrect digest was found for the ($keyring) keyring"
+			tst_res TFAIL "incorrect digest was found for $keyring keyring"
 			return
 		fi
 	done
@@ -61,4 +65,52 @@ 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()
+{
+	tst_require_cmds evmctl keyctl openssl
+
+	local cert_file="$TST_DATAROOT/x509_ima.der"
+	local keyring_name="key_import_test"
+	local temp_file="file.txt"
+	local keyring_id
+
+	tst_res TINFO "verify measurement of certificate imported into a keyring"
+
+	if ! check_ima_policy_content "^measure.*func=KEY_CHECK.*keyrings=.*$keyring_name"; then
+		tst_brk TCONF "IMA policy does not contain $keyring_name keyring"
+	fi
+
+	keyctl new_session > /dev/null
+
+	keyring_id=$(keyctl newring $keyring_name @s) || \
+		tst_brk TBROK "unable to create a new keyring"
+
+	tst_is_num $keyring_id || \
+		tst_brk TBROK "unable to parse the new keyring id"
+
+	evmctl import $cert_file $keyring_id > /dev/null || \
+		tst_brk TBROK "unable to import a certificate into $keyring_name keyring"
+
+	grep $keyring_name $ASCII_MEASUREMENTS | tail -n1 | cut -d' ' -f6 | \
+		xxd -r -p > $temp_file
+
+	if [ ! -s $temp_file ]; then
+		tst_res TFAIL "keyring $keyring_name not found in $ASCII_MEASUREMENTS"
+		return
+	fi
+
+	if ! openssl x509 -in $temp_file -inform der > /dev/null; then
+		tst_res TFAIL "logged certificate is not a valid x509 certificate"
+		return
+	fi
+
+	if cmp -s $temp_file $cert_file; then
+		tst_res TPASS "logged certificate matches the original"
+	else
+		tst_res TFAIL "logged certificate does not match original"
+	fi
+}
+
 tst_run
-- 
2.28.0



More information about the ltp mailing list