[PATCH v2 2/3] tests: Add program to create IMA signature with new API call

[Stefan Berger <stefanb@linux.ibm.com>]

Since the new API call is not used by evmctl, implement a test program
'create_ima_signature' to use it. Extend _evmctl_sign to also created
IMA v2 signatures with RSA keys using this test program and compare the
results.

Evmctl's signature creation path is unmodified at this point, so the tests
ensure that the existing sign_hash_v2 and the new sign_hash_v2_pkey create
identical (RSA) signatures.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
 tests/Makefile.am            |   6 ++
 tests/create_ima_signature.c | 111 +++++++++++++++++++++++++++++++++++
 tests/sign_verify.test       |  21 ++++++-
 3 files changed, 136 insertions(+), 2 deletions(-)
 create mode 100644 tests/create_ima_signature.c

diff --git a/tests/Makefile.am b/tests/Makefile.am
index ff928e1..5e255b1 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -3,6 +3,12 @@ TESTS = $(check_SCRIPTS)
 
 check_SCRIPTS += ima_hash.test sign_verify.test boot_aggregate.test
 
+check_PROGRAMS = \
+	create_ima_signature
+
+create_ima_signature_CFLAGS = -I$(top_srcdir)/src
+create_ima_signature_LDFLAGS = -lcrypto -L$(top_builddir)/src/.libs -limaevm
+
 clean-local:
 	-rm -f *.txt *.out *.sig *.sig2
 
diff --git a/tests/create_ima_signature.c b/tests/create_ima_signature.c
new file mode 100644
index 0000000..649efcf
--- /dev/null
+++ b/tests/create_ima_signature.c
@@ -0,0 +1,111 @@
+/*
+ * create_ima_signature - Test program for imaevm_create_ima_signature
+ *
+ * Copyright (C) 2021 IBM Corporation
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * As a special exception, the copyright holders give permission to link the
+ * code of portions of this program with the OpenSSL library under certain
+ * conditions as described in each individual source file and distribute
+ * linked combinations including the program with the OpenSSL library. You
+ * must comply with the GNU General Public License in all respects
+ * for all of the code used other than as permitted herein. If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so. If you do not
+ * wish to do so, delete this exception statement from your version. If you
+ * delete this exception statement from all source files in the program,
+ * then also delete it in the license file.
+ *
+ */
+
+#include <getopt.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <openssl/pem.h>
+
+#include "imaevm.h"
+
+int main(int argc, char *argv[]) {
+	unsigned char ima_signature[MAX_SIGNATURE_SIZE];
+	static struct option long_options[] = {
+		{"key", required_argument, NULL, 'k'},
+		{"hashalgo", required_argument, NULL, 'a'},
+		{NULL, 0, NULL, 0}
+	};
+	const char *hash_algo = "sha1";
+	const char *keyfile = NULL;
+	const char *file_to_sign;
+	EVP_PKEY *pkey = NULL;
+	char *error = NULL;
+	int option_index;
+	int siglen;
+	size_t i;
+	FILE *fp;
+	int opt;
+
+	while ((opt = getopt_long_only(argc, argv, "", long_options, &option_index)) != -1) {
+		switch (opt) {
+		case 'k':
+			keyfile = optarg;
+			break;
+		case 'a':
+			hash_algo = optarg;
+			break;
+		default:
+			fprintf(stderr, "Unhandled option %d.\n", opt);
+			return 1;
+		}
+	}
+	if (keyfile == NULL) {
+		fprintf(stderr, "Missing --key option.\n");
+		return 1;
+	}
+
+	if (optind == argc) {
+		fprintf(stderr, "Missing filename for file to sign.");
+	}
+
+	file_to_sign = argv[optind];
+
+	fp = fopen(keyfile, "r");
+	if (fp == NULL) {
+		fprintf(stderr, "Could not open private key file: %s\n", strerror(errno));
+		return 1;
+	}
+
+	pkey = PEM_read_PrivateKey(fp, NULL, NULL, NULL);
+	fclose(fp);
+	if (pkey == NULL) {
+		fprintf(stderr, "Could not read private key!\n");
+		return 1;
+	}
+
+	/* the library doesn't prepend this! */
+	ima_signature[0] = EVM_IMA_XATTR_DIGSIG;
+	siglen = imaevm_create_ima_signature(file_to_sign, pkey, hash_algo, &ima_signature[1],
+	                                     sizeof(ima_signature) - 1, &error);
+	if (siglen < 0) {
+		fprintf(stderr, "Failed to created IMA signature: %s\n", error);
+	} else {
+		fprintf(stdout, "Successfully created IMA signature!\n");
+		for (i = 0; i < siglen + 1; i++)
+			fprintf(stdout, "%02x", ima_signature[i]);
+		fprintf(stdout, "\n");
+	}
+
+	free(error);
+	EVP_PKEY_free(pkey);
+
+	return siglen < 0;
+}
diff --git a/tests/sign_verify.test b/tests/sign_verify.test
index 288e133..14964ec 100755
--- a/tests/sign_verify.test
+++ b/tests/sign_verify.test
@@ -16,10 +16,10 @@
 # GNU General Public License for more details.
 
 cd "$(dirname "$0")" || exit 1
-PATH=../src:$PATH
+PATH=../src:.:$PATH
 source ./functions.sh
 
-_require cmp evmctl getfattr openssl xxd
+_require cmp evmctl getfattr openssl xxd create_ima_signature
 
 if cmp -b 2>&1 | grep -q "invalid option"; then
 	echo "cmp does not support -b (cmp from busybox?) Use cmp from diffutils"
@@ -118,7 +118,24 @@ _evmctl_sign() {
 
   if [ "$type" = ima ]; then
     _test_sigfile "$file" "$(_xattr "$type")" "$file.sig" "$file.sig2"
+    if [ $? -ne $OK ]; then
+        return "$FAIL"
+    fi
+  fi
+  # Compare evmctl IMA v2 signatures with RSA keys versus those from create_ima_signature
+  if [ "$type" = ima ] && [[ $key =~ rsa ]] && ! [[ $opts =~ --rsa ]] ; then
+    create_ima_signature --key "${key}" --hashalgo "${alg}" "${file}" |
+      sed -n 's/^03.*/\0/p' |
+      xxd -r -p > "$file.sig2"
+
+    if ! cmp -bl "$file.sig" "$file.sig2"; then
+      color_red
+      echo "evmctl vs. create_ima_signature: signatures on $file differ"
+      color_restore
+      return "$FAIL"
+    fi
   fi
+  return $OK
 }
 
 # Run and test {ima_,}sign operation
-- 
2.30.2