From 32ecff8587a1825d20be9db3fb567e0460f945a9 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Thu, 13 Jun 2024 01:31:26 +0200
Subject: [PATCH] Add test for parsing legacy ed25519 signatures with short
 MPIs

---
 .../openpgp/test/PGPSignatureTest.java        | 23 ++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/pg/src/test/java/org/bouncycastle/openpgp/test/PGPSignatureTest.java b/pg/src/test/java/org/bouncycastle/openpgp/test/PGPSignatureTest.java
index 5f49cdc655..4b6687927b 100644
--- a/pg/src/test/java/org/bouncycastle/openpgp/test/PGPSignatureTest.java
+++ b/pg/src/test/java/org/bouncycastle/openpgp/test/PGPSignatureTest.java
@@ -11,13 +11,22 @@
 import java.util.Date;
 import java.util.Iterator;
 
-import org.bouncycastle.bcpg.*;
+import org.bouncycastle.bcpg.ArmoredInputStream;
+import org.bouncycastle.bcpg.BCPGInputStream;
+import org.bouncycastle.bcpg.CompressionAlgorithmTags;
+import org.bouncycastle.bcpg.HashAlgorithmTags;
+import org.bouncycastle.bcpg.PublicKeyAlgorithmTags;
+import org.bouncycastle.bcpg.SignatureSubpacket;
+import org.bouncycastle.bcpg.SignatureSubpacketInputStream;
+import org.bouncycastle.bcpg.SignatureSubpacketTags;
+import org.bouncycastle.bcpg.SymmetricKeyAlgorithmTags;
 import org.bouncycastle.bcpg.sig.IntendedRecipientFingerprint;
 import org.bouncycastle.bcpg.sig.IssuerFingerprint;
 import org.bouncycastle.bcpg.sig.KeyFlags;
 import org.bouncycastle.bcpg.sig.NotationData;
 import org.bouncycastle.bcpg.sig.SignatureTarget;
 import org.bouncycastle.jce.provider.BouncyCastleProvider;
+import org.bouncycastle.math.ec.rfc8032.Ed25519;
 import org.bouncycastle.openpgp.PGPException;
 import org.bouncycastle.openpgp.PGPLiteralData;
 import org.bouncycastle.openpgp.PGPLiteralDataGenerator;
@@ -759,6 +768,7 @@ public void performTest()
         testUserAttributeEncoding();
         testExportNonExportableSignature();
         testRejectionOfIllegalSignatureType0xFF();
+        testGetSignatureOfLegacyEd25519KeyWithShortMPIs();
     }
 
     private void testUserAttributeEncoding()
@@ -1413,6 +1423,17 @@ private void testRejectionOfIllegalSignatureType0xFF()
         }
     }
 
+    private void testGetSignatureOfLegacyEd25519KeyWithShortMPIs()
+            throws PGPException, IOException
+    {
+        String ed25519KeyWithShortSignatureMPIs = "88740401160a00270502666a2d4009105ac5b83f1a5ad687162104229cfc85fe0ca2e3718b022c5ac5b83f1a5ad6870000a16b00f7754c1d14b068ae5e6816c376367569b1ae984587e8e5ec3cc54b811549a4920100ca2159e5965bf7d8655385449994aead14ccf05c3f33335b98d305c0f20ef50e";
+        ByteArrayInputStream bIn = new ByteArrayInputStream(Hex.decode(ed25519KeyWithShortSignatureMPIs));
+        BCPGInputStream pIn = new BCPGInputStream(bIn);
+        PGPSignature signature = new PGPSignature(pIn);
+        isEquals("Short MPIs in LegacyEd25519 signature MUST be properly parsed",
+                Ed25519.SIGNATURE_SIZE, signature.getSignature().length);
+    }
+
     private PGPSignatureList readSignatures(String armored)
         throws IOException
     {