fix csr encoding

a-sit-plus · Oct 8, 2024 · 1e3bcc8 · 1e3bcc8
1 parent 0cdf4be
commit 1e3bcc8
Show file tree

Hide file tree

Showing 2 changed files with 52 additions and 4 deletions.
diff --git a/.../src/commonMain/kotlin/at/asitplus/signum/indispensable/pki/Pkcs10CertificationRequest.kt b/.../src/commonMain/kotlin/at/asitplus/signum/indispensable/pki/Pkcs10CertificationRequest.kt
@@ -37,14 +37,18 @@ data class TbsCertificationRequest(
     constructor(
         subjectName: List<RelativeDistinguishedName>,
         publicKey: CryptoPublicKey,
-        extensions: List<X509CertificateExtension>,
+        extensions: List<X509CertificateExtension>? = null,
         version: Int = 0,
         attributes: List<Pkcs10CertificationRequestAttribute>? = null,
     ) : this(version, subjectName, publicKey, mutableListOf<Pkcs10CertificationRequestAttribute>().also { attrs ->
         attributes?.let { attrs.addAll(it) }
-        attrs.add(Pkcs10CertificationRequestAttribute(KnownOIDs.extensionRequest, Asn1.Sequence {
-            extensions.forEach { +it }
-        }))
+        extensions?.let { extn ->
+            attrs.add(
+                Pkcs10CertificationRequestAttribute(
+                    KnownOIDs.extensionRequest,
+                    Asn1.Sequence { extn.forEach { +it } })
+            )
+        }
     })
 
     override fun encodeToTlv() = Asn1.Sequence {

diff --git a/.../src/jvmTest/kotlin/at/asitplus/signum/indispensable/Pkcs10CertificationRequestJvmTest.kt b/.../src/jvmTest/kotlin/at/asitplus/signum/indispensable/Pkcs10CertificationRequestJvmTest.kt
@@ -213,6 +213,50 @@ class Pkcs10CertificationRequestJvmTest : FreeSpec({
         parsedFromKotlinCsr.isSignatureValid(JcaContentVerifierProviderBuilder().build(keyPair.public))
     }
 
+    "CSRs with empty extensions match" {
+        val ecPublicKey = keyPair.public as ECPublicKey
+        val cryptoPublicKey = CryptoPublicKey.EC.fromJcaPublicKey(ecPublicKey).getOrThrow()
+
+        // create CSR with bouncycastle
+        val commonName = "localhost"
+        val signatureAlgorithm = X509SignatureAlgorithm.ES256
+        val contentSigner: ContentSigner = signatureAlgorithm.getContentSigner(keyPair.private)
+        val spki = SubjectPublicKeyInfo.getInstance(keyPair.public.encoded)
+
+
+
+        val bcCsr = PKCS10CertificationRequestBuilder(X500Name("CN=$commonName"), spki)
+            .addAttribute(ASN1ObjectIdentifier("1.2.1840.13549.1.9.16.1337.26"), ASN1Integer(1337L))
+            .build(contentSigner)
+        val tbsCsr = TbsCertificationRequest(
+            subjectName = listOf(RelativeDistinguishedName(AttributeTypeAndValue.CommonName(Asn1String.UTF8(commonName)))),
+            publicKey = cryptoPublicKey,
+            extensions = null,
+            attributes = listOf(
+                Pkcs10CertificationRequestAttribute(
+                    ObjectIdentifier("1.2.1840.13549.1.9.16.1337.26"),
+                    1337.encodeToAsn1Primitive()
+                )
+            )
+        )
+        val signed = signatureAlgorithm.getJCASignatureInstance().getOrThrow().apply {
+            initSign(keyPair.private)
+            update(tbsCsr.encodeToTlv().derEncoded)
+        }.sign()
+        val csr = Pkcs10CertificationRequest(tbsCsr, signatureAlgorithm, CryptoSignature.parseFromJca(signed,signatureAlgorithm))
+
+        val kotlinEncoded = csr.encodeToTlv().derEncoded
+        val jvmEncoded = bcCsr.encoded
+        println(jvmEncoded.toHexString(HexFormat.UpperCase))
+        println(kotlinEncoded.toHexString(HexFormat.UpperCase))
+        // CSR will never entirely match because of randomness in ECDSA signature
+        //kotlinEncoded shouldBe jvmEncoded
+        kotlinEncoded.drop(6).take(152) shouldBe jvmEncoded.drop(6).take(152)
+
+        val parsedFromKotlinCsr = PKCS10CertificationRequest(kotlinEncoded)
+        parsedFromKotlinCsr.isSignatureValid(JcaContentVerifierProviderBuilder().build(keyPair.public))
+    }
+
     "CSR can be parsed" {
         val ecPublicKey = keyPair.public as ECPublicKey
         val keyX = ecPublicKey.w.affineX.toByteArray().ensureSize(ecCurve.coordinateLength.bytes)