[RFC PATCH ima-evm-utils 04/11] Deprecate IMA signature version 1

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The original IMA file signatures were based on a SHA1 hash.  Kernel
support for other hash algorithms was subsequently upstreamed.  Deprecate
"--rsa" support.

Define "--enable-sigv1" option to configure signature v1 support.

Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
---
 configure.ac           |  6 ++++++
 src/Makefile.am        | 10 ++++++++++
 src/evmctl.c           | 16 ++++++++++++----
 src/libimaevm.c        | 24 ++++++++++++++++++++++--
 tests/sign_verify.test | 18 ++++++++++++------
 5 files changed, 62 insertions(+), 12 deletions(-)

diff --git a/configure.ac b/configure.ac
index 9d3b23ff8def..dc666f2bb1fa 100644
--- a/configure.ac
+++ b/configure.ac
@@ -49,6 +49,11 @@ AC_ARG_ENABLE([openssl_conf],
 		AC_DEFINE(DISABLE_OPENSSL_CONF, 1, [Define to disable loading of openssl config by evmctl.])
 	      fi], [enable_openssl_conf=yes])
 
+AC_ARG_ENABLE(sigv1,
+	      AS_HELP_STRING([--enable-sigv1], [Build ima-evm-utils with signature v1 support]))
+	AM_CONDITIONAL([CONFIG_SIGV1], [test "x$enable_sigv1" = "xyes"])
+	AS_IF([test "$enable_sigv1"  != "yes"], [enable_sigv1="no"])
+
 #debug support - yes for a while
 PKG_ARG_ENABLE(debug, "yes", DEBUG, [Enable Debug support])
 if test $pkg_cv_enable_debug = yes; then
@@ -83,5 +88,6 @@ echo	"   openssl-conf: $enable_openssl_conf"
 echo	"      tss2-esys: $ac_cv_lib_tss2_esys_Esys_Free"
 echo	" tss2-rc-decode: $ac_cv_lib_tss2_rc_Tss2_RC_Decode"
 echo    "         ibmtss: $ac_cv_header_ibmtss_tss_h"
+echo    "         sigv1:  $enable_sigv1"
 echo	"            doc: $have_doc"
 echo
diff --git a/src/Makefile.am b/src/Makefile.am
index 396496bb439d..90c7249020cf 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -7,6 +7,10 @@ libimaevm_la_CPPFLAGS = $(AM_CPPFLAGS) $(LIBCRYPTO_CFLAGS)
 libimaevm_la_LDFLAGS = -version-info 3:0:0
 libimaevm_la_LIBADD =  $(LIBCRYPTO_LIBS)
 
+if CONFIG_SIGV1
+libimaevm_la_CFLAGS = -DCONFIG_SIGV1
+endif
+
 include_HEADERS = imaevm.h
 
 nodist_libimaevm_la_SOURCES = hash_info.h
@@ -22,6 +26,12 @@ evmctl_CPPFLAGS = $(AM_CPPFLAGS) $(LIBCRYPTO_CFLAGS)
 evmctl_LDFLAGS = $(LDFLAGS_READLINE)
 evmctl_LDADD =  $(LIBCRYPTO_LIBS) -lkeyutils libimaevm.la
 
+# Enable IMA signature version 1
+if CONFIG_SIGV1
+evmctl_CFLAGS = -DCONFIG_SIGV1
+endif
+
+
 # USE_PCRTSS uses the Intel TSS
 if USE_PCRTSS
  evmctl_SOURCES += pcr_tss.c
diff --git a/src/evmctl.c b/src/evmctl.c
index 76e2561798fa..621136b5b85f 100644
--- a/src/evmctl.c
+++ b/src/evmctl.c
@@ -987,7 +987,6 @@ static int cmd_verify_ima(struct command *cmd)
 			init_public_keys("/etc/keys/x509_evm.der");
 	}
 
-	errno = 0;
 	if (!file) {
 		log_err("Parameters missing\n");
 		print_usage(cmd);
@@ -1006,6 +1005,7 @@ static int cmd_verify_ima(struct command *cmd)
 
 static int cmd_convert(struct command *cmd)
 {
+#if CONFIG_SIGV1
 	char *inkey;
 	unsigned char _pub[1024], *pub = _pub;
 	int len, err = 0;
@@ -1033,6 +1033,8 @@ static int cmd_convert(struct command *cmd)
 
 	RSA_free(key);
 	return err;
+#endif
+	return 77;
 }
 
 static int cmd_import(struct command *cmd)
@@ -1088,6 +1090,7 @@ static int cmd_import(struct command *cmd)
 		calc_keyid_v2((uint32_t *)keyid, name, pkey);
 		EVP_PKEY_free(pkey);
 	} else {
+#if CONFIG_SIGV1
 		RSA *key = read_pub_key(inkey, imaevm_params.x509);
 
 		if (!key)
@@ -1095,6 +1098,10 @@ static int cmd_import(struct command *cmd)
 		len = key2bin(key, pub);
 		calc_keyid_v1(keyid, name, pub, len);
 		RSA_free(key);
+#else
+		log_info("Importing public RSA key not supported\n");
+		return 1;
+#endif
 	}
 
 	log_info("Importing public key %s from file %s into keyring %d\n", name, inkey, id);
@@ -2598,7 +2605,8 @@ static void usage(void)
 		"  -d, --imahash      make IMA hash\n"
 		"  -f, --sigfile      store IMA signature in .sig file instead of xattr\n"
 		"      --xattr-user   store xattrs in user namespace (for testing purposes)\n"
-		"      --rsa          use RSA key type and signing scheme v1\n"
+
+		"      --rsa          use RSA key type and signing scheme v1 (deprecated)\n"
 		"  -k, --key          path to signing key (default: /etc/keys/{privkey,pubkey}_evm.pem)\n"
 		"                     or a pkcs11 URI\n"
 		"      --keyid n      overwrite signature keyid with a 32-bit value in hex (for signing)\n"
@@ -2637,8 +2645,8 @@ static void usage(void)
 struct command cmds[] = {
 	{"--version", NULL, 0, ""},
 	{"help", cmd_help, 0, "<command>"},
-	{"import", cmd_import, 0, "[--rsa] pubkey keyring", "Import public key into the keyring.\n"},
-	{"convert", cmd_convert, 0, "key", "convert public key into the keyring.\n"},
+	{"import", cmd_import, 0, "[--rsa] pubkey keyring", "Import public key into the keyring. (deprecated)\n"},
+	{"convert", cmd_convert, 0, "key", "convert public key into the keyring. (deprecated)\n"},
 	{"sign", cmd_sign_evm, 0, "[-r] [--imahash | --imasig ] [--key key] [--pass [password] file", "Sign file metadata.\n"},
 	{"verify", cmd_verify_evm, 0, "file", "Verify EVM signature (for debugging).\n"},
 	{"ima_sign", cmd_sign_ima, 0, "[--sigfile] [--key key] [--pass [password] file", "Make file content signature.\n"},
diff --git a/src/libimaevm.c b/src/libimaevm.c
index e4b62b4989b2..cb815f953a80 100644
--- a/src/libimaevm.c
+++ b/src/libimaevm.c
@@ -294,8 +294,9 @@ out:
 
 RSA *read_pub_key(const char *keyfile, int x509)
 {
+	RSA *key = NULL;
+#if CONFIG_SIGV1
 	EVP_PKEY *pkey;
-	RSA *key;
 
 	pkey = read_pub_pkey(keyfile, x509);
 	if (!pkey)
@@ -307,9 +308,11 @@ RSA *read_pub_key(const char *keyfile, int x509)
 		output_openssl_errors();
 		return NULL;
 	}
+#endif
 	return key;
 }
 
+#if CONFIG_SIGV1
 static int verify_hash_v1(const char *file, const unsigned char *hash, int size,
 			  unsigned char *sig, int siglen, const char *keyfile)
 {
@@ -351,6 +354,7 @@ static int verify_hash_v1(const char *file, const unsigned char *hash, int size,
 
 	return 0;
 }
+#endif
 
 struct public_key_entry {
 	struct public_key_entry *next;
@@ -686,6 +690,7 @@ int verify_hash(const char *file, const unsigned char *hash, int size,
 {
 	/* Get signature type from sig header */
 	if (sig[1] == DIGSIG_VERSION_1) {
+#if CONFIG_SIGV1
 		const char *key = NULL;
 
 		/* Read pubkey from RSA key */
@@ -695,6 +700,10 @@ int verify_hash(const char *file, const unsigned char *hash, int size,
 			key = imaevm_params.keyfile;
 		return verify_hash_v1(file, hash, size, sig + 1, siglen - 1,
 					 key);
+#else
+		log_info("Signature version 1 deprecated.");
+		return -1;
+#endif
 	} else if (sig[1] == DIGSIG_VERSION_2) {
 		return verify_hash_v2(file, hash, size, sig, siglen);
 	} else if (sig[1] == DIGSIG_VERSION_3) {
@@ -747,6 +756,7 @@ int ima_verify_signature(const char *file, unsigned char *sig, int siglen,
  */
 int key2bin(RSA *key, unsigned char *pub)
 {
+#if CONFIG_SIGV1
 	int len, b, offset = 0;
 	struct pubkey_hdr *pkh = (struct pubkey_hdr *)pub;
 	const BIGNUM *n, *e;
@@ -781,10 +791,14 @@ int key2bin(RSA *key, unsigned char *pub)
 	offset += len;
 
 	return offset;
+#else
+	return 77; /* SKIP */
+#endif
 }
 
 void calc_keyid_v1(uint8_t *keyid, char *str, const unsigned char *pkey, int len)
 {
+#if CONFIG_SIGV1
 	uint8_t sha1[SHA_DIGEST_LENGTH];
 	uint64_t id;
 
@@ -799,6 +813,7 @@ void calc_keyid_v1(uint8_t *keyid, char *str, const unsigned char *pkey, int len
 
 	if (imaevm_params.verbose > LOG_INFO)
 		log_info("keyid-v1: %s\n", str);
+#endif
 }
 
 /*
@@ -990,10 +1005,11 @@ err_engine:
 	return NULL;
 }
 
+#if CONFIG_SIGV1
 static RSA *read_priv_key(const char *keyfile, const char *keypass)
 {
+	RSA *key = NULL;
 	EVP_PKEY *pkey;
-	RSA *key;
 
 	pkey = read_priv_pkey(keyfile, keypass);
 	if (!pkey)
@@ -1018,10 +1034,12 @@ static int get_hash_algo_v1(const char *algo)
 
 	return -1;
 }
+#endif
 
 static int sign_hash_v1(const char *hashalgo, const unsigned char *hash,
 			int size, const char *keyfile, unsigned char *sig)
 {
+#if CONFIG_SIGV1
 	int len = -1, hashalgo_idx;
 	SHA_CTX ctx;
 	unsigned char pub[1024];
@@ -1099,6 +1117,8 @@ static int sign_hash_v1(const char *hashalgo, const unsigned char *hash,
 out:
 	RSA_free(key);
 	return len;
+#endif
+	return 77;  /* SKIP */
 }
 
 /*
diff --git a/tests/sign_verify.test b/tests/sign_verify.test
index c56290aa4932..948892759424 100755
--- a/tests/sign_verify.test
+++ b/tests/sign_verify.test
@@ -17,6 +17,7 @@
 
 cd "$(dirname "$0")" || exit 1
 PATH=../src:$PATH
+SIGV1=0
 source ./functions.sh
 
 _require cmp evmctl getfattr openssl xxd
@@ -368,13 +369,18 @@ try_different_sigs() {
 
 ## Test v1 signatures
 # Signature v1 only supports sha1 and sha256 so any other should fail
-expect_fail \
-  check_sign TYPE=ima KEY=rsa1024 ALG=md5 PREFIX=0x0301 OPTS=--rsa
+if [ $SIGV1 -eq 0 ]; then
+  __skip() { echo "IMA signature v1 tests are skipped: not supported"; return $SKIP; }
+  expect_pass __skip
+else
+   expect_fail \
+      check_sign TYPE=ima KEY=rsa1024 ALG=md5 PREFIX=0x0301 OPTS=--rsa
 
-sign_verify  rsa1024  sha1    0x0301 --rsa
-sign_verify  rsa1024  sha256  0x0301 --rsa
-  try_different_keys
-  try_different_sigs
+   sign_verify  rsa1024  sha1    0x0301 --rsa
+   sign_verify  rsa1024  sha256  0x0301 --rsa
+      try_different_keys
+      try_different_sigs
+fi
 
 ## Test v2 signatures with RSA PKCS#1
 # List of allowed hashes much greater but not all are supported.
-- 
2.31.1




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