From f45254cf0725c2d6ab95dcfa74300d0978853a63 Mon Sep 17 00:00:00 2001
From: David Hedberg <david.hedberg@gmail.com>
Date: Sat, 27 Mar 2021 11:37:44 +0100
Subject: [PATCH] Only skip hashing when creating an EDDSA authentication
 signature

---
 .../jcajce/NfcSyncPGPContentSignerBuilder.java | 14 +++++++++++---
 .../keychain/pgp/CanonicalizedSecretKey.java   | 18 ++++++++++++------
 2 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/OpenKeychain/src/main/java/org/bouncycastle/openpgp/operator/jcajce/NfcSyncPGPContentSignerBuilder.java b/OpenKeychain/src/main/java/org/bouncycastle/openpgp/operator/jcajce/NfcSyncPGPContentSignerBuilder.java
index 95580d07a..dd4db13c3 100644
--- a/OpenKeychain/src/main/java/org/bouncycastle/openpgp/operator/jcajce/NfcSyncPGPContentSignerBuilder.java
+++ b/OpenKeychain/src/main/java/org/bouncycastle/openpgp/operator/jcajce/NfcSyncPGPContentSignerBuilder.java
@@ -34,6 +34,7 @@ public class NfcSyncPGPContentSignerBuilder
     private int     hashAlgorithm;
     private int     keyAlgorithm;
     private long    keyID;
+    private boolean isEdDsaAuthenticationSignature = false;
 
     private Map signedHashes;
 
@@ -86,6 +87,13 @@ public class NfcSyncPGPContentSignerBuilder
         return this;
     }
 
+    public NfcSyncPGPContentSignerBuilder configureForEdDsaAuthenticationSignature()
+    {
+        isEdDsaAuthenticationSignature = true;
+
+        return this;
+    }
+
     public PGPContentSigner build(final int signatureType, PGPPrivateKey privateKey)
         throws PGPException {
         // NOTE: privateKey is null in this case!
@@ -95,8 +103,8 @@ public class NfcSyncPGPContentSignerBuilder
     public PGPContentSigner build(final int signatureType, final long keyID)
         throws PGPException
     {
-        if (keyAlgorithm == PublicKeyAlgorithmTags.EDDSA) {
-            return buildEdDSASigner(signatureType, keyID);
+        if (isEdDsaAuthenticationSignature) {
+            return buildEdDSAAuthenticationSigner(signatureType, keyID);
         }
 
         final PGPDigestCalculator digestCalculator = digestCalculatorProviderBuilder.build().get(hashAlgorithm);
@@ -146,7 +154,7 @@ public class NfcSyncPGPContentSignerBuilder
         };
     }
 
-    public PGPContentSigner buildEdDSASigner(final int signatureType, final long keyID)
+    public PGPContentSigner buildEdDSAAuthenticationSigner(final int signatureType, final long keyID)
         throws PGPException
     {
         final ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/CanonicalizedSecretKey.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/CanonicalizedSecretKey.java
index 6ee583e8c..4c1e901d6 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/CanonicalizedSecretKey.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/CanonicalizedSecretKey.java
@@ -255,14 +255,20 @@ public class CanonicalizedSecretKey extends CanonicalizedPublicKey {
 
     private PGPContentSignerBuilder getAuthenticationContentSignerBuilder(int hashAlgorithm, Map<ByteBuffer,
             byte[]> signedHashes) {
-        if (
-            getAlgorithm() == PublicKeyAlgorithmTags.EDDSA
-                && mPrivateKeyState != PRIVATE_KEY_STATE_DIVERT_TO_CARD) {
+        if (getAlgorithm() == PublicKeyAlgorithmTags.EDDSA) {
             // content signer feeding the input directly into the signature engine,
             // since EdDSA hashes the input anyway
-            return new EdDsaAuthenticationContentSignerBuilder(
-                    mSecretKey.getPublicKey().getAlgorithm(), hashAlgorithm)
-                    .setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
+            if (mPrivateKeyState == PRIVATE_KEY_STATE_DIVERT_TO_CARD) {
+                return new NfcSyncPGPContentSignerBuilder(
+                        mSecretKey.getPublicKey().getAlgorithm(), hashAlgorithm,
+                        mSecretKey.getKeyID(), signedHashes)
+                        .configureForEdDsaAuthenticationSignature()
+                        .setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
+            } else {
+                return new EdDsaAuthenticationContentSignerBuilder(
+                        mSecretKey.getPublicKey().getAlgorithm(), hashAlgorithm)
+                        .setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
+            }
         } else {
             return getContentSignerBuilder(hashAlgorithm, signedHashes);
         }