From d95afbf5c329d51c2a92099e8db84f7fc2028602 Mon Sep 17 00:00:00 2001
From: David Hook <dgh@cryptoworkshop.com>
Date: Wed, 4 Dec 2024 09:19:41 +1100
Subject: [PATCH] updated BufferingContentSigner to use ExtendedContentSigner

---
 .../cms/SignerInfoGeneratorBuilder.java       | 24 +++++++++++--------
 .../operator/BufferingContentSigner.java      | 19 ++++++++++++++-
 .../operator/ExtendedContentSigner.java       |  6 ++---
 3 files changed, 35 insertions(+), 14 deletions(-)

diff --git a/pkix/src/main/java/org/bouncycastle/cms/SignerInfoGeneratorBuilder.java b/pkix/src/main/java/org/bouncycastle/cms/SignerInfoGeneratorBuilder.java
index aea54192d3..7ad627e487 100644
--- a/pkix/src/main/java/org/bouncycastle/cms/SignerInfoGeneratorBuilder.java
+++ b/pkix/src/main/java/org/bouncycastle/cms/SignerInfoGeneratorBuilder.java
@@ -147,21 +147,25 @@ private SignerInfoGenerator createGenerator(ContentSigner contentSigner, SignerI
         }
         else
         {
+            AlgorithmIdentifier digestAlgorithmIdentifier = null;
+
             if (contentSigner instanceof ExtendedContentSigner)
             {
-                digester = digestProvider.get(((ExtendedContentSigner)contentSigner).getDigestAlgorithmIdentifier());
+                digestAlgorithmIdentifier = ((ExtendedContentSigner)contentSigner).getDigestAlgorithmIdentifier();
+            }
+
+            if (digestAlgorithmIdentifier == null)
+            {
+                digestAlgorithmIdentifier = digAlgFinder.find(contentSigner.getAlgorithmIdentifier());
+            }
+
+            if (digestAlgorithmIdentifier != null)
+            {
+                digester = digestProvider.get(digestAlgorithmIdentifier);
             }
             else
             {
-                AlgorithmIdentifier digAlg = digAlgFinder.find(contentSigner.getAlgorithmIdentifier());
-                if (digAlg != null)
-                {
-                    digester = digestProvider.get(digAlg);
-                }
-                else
-                {
-                    throw new OperatorCreationException("no digest algorithm specified for signature algorithm");
-                }
+                throw new OperatorCreationException("no digest algorithm specified for signature algorithm");
             }
         }
 
diff --git a/pkix/src/main/java/org/bouncycastle/operator/BufferingContentSigner.java b/pkix/src/main/java/org/bouncycastle/operator/BufferingContentSigner.java
index d174367299..6e71ebf408 100644
--- a/pkix/src/main/java/org/bouncycastle/operator/BufferingContentSigner.java
+++ b/pkix/src/main/java/org/bouncycastle/operator/BufferingContentSigner.java
@@ -10,7 +10,7 @@
  * block when ready for signing.
  */
 public class BufferingContentSigner
-    implements ContentSigner
+    implements ExtendedContentSigner
 {
     private final ContentSigner contentSigner;
     private final OutputStream  output;
@@ -67,4 +67,21 @@ public byte[] getSignature()
     {
         return contentSigner.getSignature();
     }
+
+
+    /**
+     * Return the algorithm identifier describing the digest
+     * algorithm used by this signature algorithm, if known.
+     *
+     * @return algorithm oid and parameters, null otherwise.
+     */
+    public AlgorithmIdentifier getDigestAlgorithmIdentifier()
+    {
+        if (contentSigner instanceof ExtendedContentSigner)
+        {
+            return ((ExtendedContentSigner)contentSigner).getDigestAlgorithmIdentifier();
+        }
+
+        return null;
+    }
 }
diff --git a/pkix/src/main/java/org/bouncycastle/operator/ExtendedContentSigner.java b/pkix/src/main/java/org/bouncycastle/operator/ExtendedContentSigner.java
index 455828e0bd..115e056c37 100644
--- a/pkix/src/main/java/org/bouncycastle/operator/ExtendedContentSigner.java
+++ b/pkix/src/main/java/org/bouncycastle/operator/ExtendedContentSigner.java
@@ -9,10 +9,10 @@ public interface ExtendedContentSigner
     extends ContentSigner
 {
     /**
-     * Return the algorithm identifier describing the signature
-     * algorithm and parameters this signer generates.
+     * Return the algorithm identifier describing the digest algorithm used by
+     * this signature algorithm and parameters this signer generates.
      *
-     * @return algorithm oid and parameters.
+     * @return algorithm oid and parameters, null if unknown.
      */
     AlgorithmIdentifier getDigestAlgorithmIdentifier();
 }