From 867764678091c0d9e8a161f682a3e84ee4dc9a2b Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Sun, 11 Aug 2024 13:41:17 +0200
Subject: [PATCH] V6 sigs do not contain IssuerKeyId packet

---
 .../org/pgpainless/key/generation/KeyRingBuilder.kt  |  2 +-
 .../signature/subpackets/BaseSignatureSubpackets.kt  |  9 +++++++++
 .../signature/subpackets/SignatureSubpackets.kt      | 12 ++++++++++--
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/pgpainless-core/src/main/kotlin/org/pgpainless/key/generation/KeyRingBuilder.kt b/pgpainless-core/src/main/kotlin/org/pgpainless/key/generation/KeyRingBuilder.kt
index 16b25bd3..a63c00aa 100644
--- a/pgpainless-core/src/main/kotlin/org/pgpainless/key/generation/KeyRingBuilder.kt
+++ b/pgpainless-core/src/main/kotlin/org/pgpainless/key/generation/KeyRingBuilder.kt
@@ -97,7 +97,7 @@ class KeyRingBuilder : KeyRingBuilderInterface<KeyRingBuilder> {
         val signatureGenerator = PGPSignatureGenerator(signer, certKey.publicKey)
 
         val hashedSubPacketGenerator = primaryKeySpec!!.subpacketGenerator
-        hashedSubPacketGenerator.setIssuerFingerprintAndKeyId(certKey.publicKey)
+        hashedSubPacketGenerator.setIssuer(certKey.publicKey)
         expirationDate?.let { hashedSubPacketGenerator.setKeyExpirationTime(certKey.publicKey, it) }
         if (userIds.isNotEmpty()) {
             hashedSubPacketGenerator.setPrimaryUserId()
diff --git a/pgpainless-core/src/main/kotlin/org/pgpainless/signature/subpackets/BaseSignatureSubpackets.kt b/pgpainless-core/src/main/kotlin/org/pgpainless/signature/subpackets/BaseSignatureSubpackets.kt
index b9d7fb3f..bcb86182 100644
--- a/pgpainless-core/src/main/kotlin/org/pgpainless/signature/subpackets/BaseSignatureSubpackets.kt
+++ b/pgpainless-core/src/main/kotlin/org/pgpainless/signature/subpackets/BaseSignatureSubpackets.kt
@@ -17,6 +17,15 @@ interface BaseSignatureSubpackets {
 
     interface Callback : SignatureSubpacketCallback<BaseSignatureSubpackets>
 
+    /**
+     * Depending on the key version, set appropriate issuer information (issuer key-id / issuer
+     * fingerprint).
+     *
+     * @param key issuer key
+     * @return signature subpackets
+     */
+    fun setIssuer(key: PGPPublicKey): BaseSignatureSubpackets
+
     /**
      * Add both an [IssuerKeyID] and [IssuerFingerprint] subpacket pointing to the given key.
      *
diff --git a/pgpainless-core/src/main/kotlin/org/pgpainless/signature/subpackets/SignatureSubpackets.kt b/pgpainless-core/src/main/kotlin/org/pgpainless/signature/subpackets/SignatureSubpackets.kt
index 886cedb6..dc48d1cc 100644
--- a/pgpainless-core/src/main/kotlin/org/pgpainless/signature/subpackets/SignatureSubpackets.kt
+++ b/pgpainless-core/src/main/kotlin/org/pgpainless/signature/subpackets/SignatureSubpackets.kt
@@ -72,7 +72,7 @@ class SignatureSubpackets :
             issuer: PGPPublicKey,
             base: PGPSignatureSubpacketVector
         ): SignatureSubpackets {
-            return createSubpacketsFrom(base).apply { setIssuerFingerprintAndKeyId(issuer) }
+            return createSubpacketsFrom(base).apply { setIssuer(issuer) }
         }
 
         @JvmStatic
@@ -82,7 +82,7 @@ class SignatureSubpackets :
 
         @JvmStatic
         fun createHashedSubpackets(issuer: PGPPublicKey): SignatureSubpackets {
-            return createEmptySubpackets().setIssuerFingerprintAndKeyId(issuer)
+            return createEmptySubpackets().setIssuer(issuer)
         }
 
         @JvmStatic
@@ -352,6 +352,14 @@ class SignatureSubpackets :
         this.featuresSubpacket = features
     }
 
+    override fun setIssuer(key: PGPPublicKey): SignatureSubpackets = apply {
+        if (key.version == 6) {
+            setIssuerFingerprint(key)
+        } else {
+            setIssuerFingerprintAndKeyId(key)
+        }
+    }
+
     override fun setIssuerFingerprintAndKeyId(key: PGPPublicKey): SignatureSubpackets = apply {
         setIssuerKeyId(key.keyID)
         setIssuerFingerprint(key)