From: Adrian-Ken Rueegsegger <ken@codelabs.ch>
Date: Wed, 14 Apr 2021 13:34:29 +0000 (+0200)
Subject: openssl: Consider authorityKeyIdentifier in issued_by()
X-Git-Tag: 5.9.3dr2~7
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f0c25960eda4bb6269f375a4c2f1cb39f583bed5;p=thirdparty%2Fstrongswan.git

openssl: Consider authorityKeyIdentifier in issued_by()

Prior to verifying the cryptographic signature, check if the
authorityKeyIdentifier matches the key ID of the issuing certificate if
it is available.
---

diff --git a/src/libstrongswan/plugins/openssl/openssl_x509.c b/src/libstrongswan/plugins/openssl/openssl_x509.c
index 4f8395136a..6080c20ff4 100644
--- a/src/libstrongswan/plugins/openssl/openssl_x509.c
+++ b/src/libstrongswan/plugins/openssl/openssl_x509.c
@@ -391,6 +391,7 @@ METHOD(certificate_t, issued_by, bool,
 	public_key_t *key;
 	bool valid;
 	x509_t *x509 = (x509_t*)issuer;
+	chunk_t keyid = chunk_empty;
 #if OPENSSL_VERSION_NUMBER >= 0x10100000L
 	const ASN1_BIT_STRING *sig;
 #else
@@ -417,10 +418,24 @@ METHOD(certificate_t, issued_by, bool,
 			return FALSE;
 		}
 	}
-	if (!this->issuer->equals(this->issuer, issuer->get_subject(issuer)))
+
+	/* compare keyIdentifiers if available, otherwise use DNs */
+	if (this->authKeyIdentifier.ptr)
 	{
-		return FALSE;
+		keyid = x509->get_subjectKeyIdentifier(x509);
+		if (keyid.len && !chunk_equals(keyid, this->authKeyIdentifier))
+		{
+			return FALSE;
+		}
 	}
+	if (!keyid.len)
+	{
+		if (!this->issuer->equals(this->issuer, issuer->get_subject(issuer)))
+		{
+			return FALSE;
+		}
+	}
+
 	key = issuer->get_public_key(issuer);
 	if (!key)
 	{