From e3ff1403a37ef0e42632e9ed33c149698502eaf2 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Sun, 22 Aug 2021 22:17:50 +0200
Subject: [PATCH] sop: Enforce that any secret key argument only contains a
 single secret key

---
 .../src/main/java/org/pgpainless/sop/DecryptImpl.java     | 7 +++++--
 .../src/main/java/org/pgpainless/sop/EncryptImpl.java     | 3 +++
 .../src/main/java/org/pgpainless/sop/SignImpl.java        | 8 +++++++-
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/pgpainless-sop/src/main/java/org/pgpainless/sop/DecryptImpl.java b/pgpainless-sop/src/main/java/org/pgpainless/sop/DecryptImpl.java
index e1bb6fb9..734dbee1 100644
--- a/pgpainless-sop/src/main/java/org/pgpainless/sop/DecryptImpl.java
+++ b/pgpainless-sop/src/main/java/org/pgpainless/sop/DecryptImpl.java
@@ -104,8 +104,11 @@ public class DecryptImpl implements Decrypt {
     public DecryptImpl withKey(InputStream keyIn) throws SOPGPException.KeyIsProtected, SOPGPException.BadData, SOPGPException.UnsupportedAsymmetricAlgo {
         try {
             PGPSecretKeyRingCollection secretKeys = PGPainless.readKeyRing()
-                    .keyRingCollection(keyIn, true)
-                    .getPGPSecretKeyRingCollection();
+                    .secretKeyRingCollection(keyIn);
+
+            if (secretKeys.size() != 1) {
+                throw new SOPGPException.BadData(new AssertionError("Exactly one single secret key expected. Got " + secretKeys.size()));
+            }
 
             for (PGPSecretKeyRing secretKey : secretKeys) {
                 KeyRingInfo info = new KeyRingInfo(secretKey);
diff --git a/pgpainless-sop/src/main/java/org/pgpainless/sop/EncryptImpl.java b/pgpainless-sop/src/main/java/org/pgpainless/sop/EncryptImpl.java
index 548129fa..4ff1d1e2 100644
--- a/pgpainless-sop/src/main/java/org/pgpainless/sop/EncryptImpl.java
+++ b/pgpainless-sop/src/main/java/org/pgpainless/sop/EncryptImpl.java
@@ -63,6 +63,9 @@ public class EncryptImpl implements Encrypt {
     public Encrypt signWith(InputStream keyIn) throws SOPGPException.KeyIsProtected, SOPGPException.CertCannotSign, SOPGPException.UnsupportedAsymmetricAlgo, SOPGPException.BadData {
         try {
             PGPSecretKeyRingCollection keys = PGPainless.readKeyRing().secretKeyRingCollection(keyIn);
+            if (keys.size() != 1) {
+                throw new SOPGPException.BadData(new AssertionError("Exactly one secret key at a time expected. Got " + keys.size()));
+            }
 
             if (signingOptions == null) {
                 signingOptions = SigningOptions.get();
diff --git a/pgpainless-sop/src/main/java/org/pgpainless/sop/SignImpl.java b/pgpainless-sop/src/main/java/org/pgpainless/sop/SignImpl.java
index 88268622..2c3f499e 100644
--- a/pgpainless-sop/src/main/java/org/pgpainless/sop/SignImpl.java
+++ b/pgpainless-sop/src/main/java/org/pgpainless/sop/SignImpl.java
@@ -24,6 +24,7 @@ import java.util.List;
 
 import org.bouncycastle.openpgp.PGPException;
 import org.bouncycastle.openpgp.PGPSecretKeyRing;
+import org.bouncycastle.openpgp.PGPSecretKeyRingCollection;
 import org.bouncycastle.openpgp.PGPSignature;
 import org.bouncycastle.util.io.Streams;
 import org.pgpainless.PGPainless;
@@ -62,7 +63,12 @@ public class SignImpl implements Sign {
     @Override
     public Sign key(InputStream keyIn) throws SOPGPException.KeyIsProtected, SOPGPException.BadData, IOException {
         try {
-            PGPSecretKeyRing key = PGPainless.readKeyRing().secretKeyRing(keyIn);
+            PGPSecretKeyRingCollection keys = PGPainless.readKeyRing().secretKeyRingCollection(keyIn);
+            if (keys.size() != 1) {
+                throw new SOPGPException.BadData(new AssertionError("Exactly one secret key at a time expected. Got " + keys.size()));
+            }
+
+            PGPSecretKeyRing key = keys.iterator().next();
             KeyRingInfo info = new KeyRingInfo(key);
             if (!info.isFullyDecrypted()) {
                 throw new SOPGPException.KeyIsProtected();