From: tb <tb@openbsd.org>
Date: Thu, 21 Apr 2022 04:48:12 +0000 (+0000)
Subject: Avoid expensive RFC 3779 checks during cert verification
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=1b14589d7355675ee5f0a7f48d40bc0065748e1b;p=openbsd

Avoid expensive RFC 3779 checks during cert verification

X509v3_{addr,asid}_is_canonical() check that the ipAddrBlocks and
autonomousSysIds extension conform to RFC 3779. These checks are not
cheap. Certs containing non-conformant extensions should not be
considered valid, so mark them with EXFLAG_INVALID while caching the
extension information in x509v3_cache_extensions(). This way the
expensive check while walking the chains during X509_verify_cert() is
replaced with a cheap check of the extension flags. This avoids a lot
of superfluous work when validating numerous certs with similar chains
against the same roots as is done in rpki-client.

Issue noticed and fix suggested by claudio
ok claudio inoguchi jsing
---

diff --git a/lib/libcrypto/x509/x509_addr.c b/lib/libcrypto/x509/x509_addr.c
index 035353826b8..d33d4f2f8ed 100644
--- a/lib/libcrypto/x509/x509_addr.c
+++ b/lib/libcrypto/x509/x509_addr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: x509_addr.c,v 1.78 2022/03/16 11:44:36 tb Exp $ */
+/*	$OpenBSD: x509_addr.c,v 1.79 2022/04/21 04:48:12 tb Exp $ */
 /*
  * Contributed to the OpenSSL Project by the American Registry for
  * Internet Numbers ("ARIN").
@@ -1780,11 +1780,11 @@ addr_validate_path_internal(X509_STORE_CTX *ctx, STACK_OF(X509) *chain,
 	if (ext == NULL) {
 		depth = 0;
 		cert = sk_X509_value(chain, depth);
+		if ((X509_get_extension_flags(cert) & EXFLAG_INVALID) != 0)
+			goto done;
 		if ((ext = cert->rfc3779_addr) == NULL)
 			goto done;
-	}
-
-	if (!X509v3_addr_is_canonical(ext)) {
+	} else if (!X509v3_addr_is_canonical(ext)) {
 		if ((ret = verify_error(ctx, cert,
 		    X509_V_ERR_INVALID_EXTENSION, depth)) == 0)
 			goto done;
@@ -1806,6 +1806,12 @@ addr_validate_path_internal(X509_STORE_CTX *ctx, STACK_OF(X509) *chain,
 	for (depth++; depth < sk_X509_num(chain); depth++) {
 		cert = sk_X509_value(chain, depth);
 
+		if ((X509_get_extension_flags(cert) & EXFLAG_INVALID) != 0) {
+			if ((ret = verify_error(ctx, cert,
+			    X509_V_ERR_INVALID_EXTENSION, depth)) == 0)
+				goto done;
+		}
+
 		if ((parent = cert->rfc3779_addr) == NULL) {
 			for (i = 0; i < sk_IPAddressFamily_num(child); i++) {
 				child_af = sk_IPAddressFamily_value(child, i);
@@ -1822,12 +1828,6 @@ addr_validate_path_internal(X509_STORE_CTX *ctx, STACK_OF(X509) *chain,
 			continue;
 		}
 
-		if (!X509v3_addr_is_canonical(parent)) {
-			if ((ret = verify_error(ctx, cert,
-			    X509_V_ERR_INVALID_EXTENSION, depth)) == 0)
-				goto done;
-		}
-
 		/*
 		 * Check that the child's resources are covered by the parent.
 		 * Each covered resource is replaced with the parent's resource
diff --git a/lib/libcrypto/x509/x509_asid.c b/lib/libcrypto/x509/x509_asid.c
index c82f2f32cc4..5f43b3030dc 100644
--- a/lib/libcrypto/x509/x509_asid.c
+++ b/lib/libcrypto/x509/x509_asid.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: x509_asid.c,v 1.30 2021/12/25 15:46:05 tb Exp $ */
+/*	$OpenBSD: x509_asid.c,v 1.31 2022/04/21 04:48:12 tb Exp $ */
 /*
  * Contributed to the OpenSSL Project by the American Registry for
  * Internet Numbers ("ARIN").
@@ -1006,14 +1006,16 @@ asid_validate_path_internal(X509_STORE_CTX *ctx, STACK_OF(X509) *chain,
 	if (ext != NULL) {
 		i = -1;
 		x = NULL;
+		if (!X509v3_asid_is_canonical(ext))
+			validation_err(X509_V_ERR_INVALID_EXTENSION);
 	} else {
 		i = 0;
 		x = sk_X509_value(chain, i);
+		if ((X509_get_extension_flags(x) & EXFLAG_INVALID) != 0)
+			goto done;
 		if ((ext = x->rfc3779_asid) == NULL)
 			goto done;
 	}
-	if (!X509v3_asid_is_canonical(ext))
-		validation_err(X509_V_ERR_INVALID_EXTENSION);
 	if (ext->asnum != NULL) {
 		switch (ext->asnum->type) {
 		case ASIdentifierChoice_inherit:
@@ -1042,13 +1044,13 @@ asid_validate_path_internal(X509_STORE_CTX *ctx, STACK_OF(X509) *chain,
 	for (i++; i < sk_X509_num(chain); i++) {
 		x = sk_X509_value(chain, i);
 
+		if ((X509_get_extension_flags(x) & EXFLAG_INVALID) != 0)
+			validation_err(X509_V_ERR_INVALID_EXTENSION);
 		if (x->rfc3779_asid == NULL) {
 			if (child_as != NULL || child_rdi != NULL)
 				validation_err(X509_V_ERR_UNNESTED_RESOURCE);
 			continue;
 		}
-		if (!X509v3_asid_is_canonical(x->rfc3779_asid))
-			validation_err(X509_V_ERR_INVALID_EXTENSION);
 		if (x->rfc3779_asid->asnum == NULL && child_as != NULL) {
 			validation_err(X509_V_ERR_UNNESTED_RESOURCE);
 			child_as = NULL;
diff --git a/lib/libcrypto/x509/x509_purp.c b/lib/libcrypto/x509/x509_purp.c
index 4d833f73ba6..ffd986b4a1a 100644
--- a/lib/libcrypto/x509/x509_purp.c
+++ b/lib/libcrypto/x509/x509_purp.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: x509_purp.c,v 1.14 2022/04/21 04:24:51 tb Exp $ */
+/* $OpenBSD: x509_purp.c,v 1.15 2022/04/21 04:48:12 tb Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2001.
  */
@@ -600,9 +600,13 @@ x509v3_cache_extensions(X509 *x)
 	x->rfc3779_addr = X509_get_ext_d2i(x, NID_sbgp_ipAddrBlock, &i, NULL);
 	if (x->rfc3779_addr == NULL && i != -1)
 		x->ex_flags |= EXFLAG_INVALID;
+	if (!X509v3_addr_is_canonical(x->rfc3779_addr))
+		x->ex_flags |= EXFLAG_INVALID;
 	x->rfc3779_asid = X509_get_ext_d2i(x, NID_sbgp_autonomousSysNum, &i, NULL);
 	if (x->rfc3779_asid == NULL && i != -1)
 		x->ex_flags |= EXFLAG_INVALID;
+	if (!X509v3_asid_is_canonical(x->rfc3779_asid))
+		x->ex_flags |= EXFLAG_INVALID;
 #endif
 
 	for (i = 0; i < X509_get_ext_count(x); i++) {