From b980fcd7b1fff3c12e07cdc8b5f8d47ab0091a27 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Fri, 29 Apr 2022 22:49:45 +0200
Subject: [PATCH] EncryptionOptions.addRecipients(collection): Disallow empty
 collections

Fixes #281
---
 .../pgpainless/encryption_signing/EncryptionOptions.java  | 6 ++++++
 .../encryption_signing/EncryptionOptionsTest.java         | 8 ++++++++
 2 files changed, 14 insertions(+)

diff --git a/pgpainless-core/src/main/java/org/pgpainless/encryption_signing/EncryptionOptions.java b/pgpainless-core/src/main/java/org/pgpainless/encryption_signing/EncryptionOptions.java
index ca7b8ddb..99059c0a 100644
--- a/pgpainless-core/src/main/java/org/pgpainless/encryption_signing/EncryptionOptions.java
+++ b/pgpainless-core/src/main/java/org/pgpainless/encryption_signing/EncryptionOptions.java
@@ -107,6 +107,9 @@ public class EncryptionOptions {
      * @return this
      */
     public EncryptionOptions addRecipients(Iterable<PGPPublicKeyRing> keys) {
+        if (!keys.iterator().hasNext()) {
+            throw new IllegalArgumentException("Set of recipient keys cannot be empty.");
+        }
         for (PGPPublicKeyRing key : keys) {
             addRecipient(key);
         }
@@ -122,6 +125,9 @@ public class EncryptionOptions {
      * @return this
      */
     public EncryptionOptions addRecipients(@Nonnull Iterable<PGPPublicKeyRing> keys, @Nonnull EncryptionKeySelector selector) {
+        if (!keys.iterator().hasNext()) {
+            throw new IllegalArgumentException("Set of recipient keys cannot be empty.");
+        }
         for (PGPPublicKeyRing key : keys) {
             addRecipient(key, selector);
         }
diff --git a/pgpainless-core/src/test/java/org/pgpainless/encryption_signing/EncryptionOptionsTest.java b/pgpainless-core/src/test/java/org/pgpainless/encryption_signing/EncryptionOptionsTest.java
index 488e5918..40a336e8 100644
--- a/pgpainless-core/src/test/java/org/pgpainless/encryption_signing/EncryptionOptionsTest.java
+++ b/pgpainless-core/src/test/java/org/pgpainless/encryption_signing/EncryptionOptionsTest.java
@@ -116,6 +116,14 @@ public class EncryptionOptionsTest {
         assertTrue(encryptionKeys.contains(encryptStorage));
     }
 
+    @Test
+    public void testAddEmptyRecipientsFails() {
+        EncryptionOptions options = new EncryptionOptions();
+        assertThrows(IllegalArgumentException.class, () -> options.addRecipients(Collections.emptyList()));
+        assertThrows(IllegalArgumentException.class, () -> options.addRecipients(Collections.emptyList(),
+                encryptionCapableKeys -> encryptionCapableKeys));
+    }
+
     @Test
     public void testAddEmptyPassphraseFails() {
         EncryptionOptions options = new EncryptionOptions();