From 2d1d5580d18d5fb50cf5e3a353b871df79f2bce6 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Fri, 1 Sep 2023 13:15:22 +0200
Subject: [PATCH] Kotlin conversion: S2KUsageFix

---
 .../key/protection/fixes/S2KUsageFix.java     | 92 -------------------
 .../key/protection/fixes/package-info.java    |  8 --
 .../key/protection/fixes/S2KUsageFix.kt       | 79 ++++++++++++++++
 3 files changed, 79 insertions(+), 100 deletions(-)
 delete mode 100644 pgpainless-core/src/main/java/org/pgpainless/key/protection/fixes/S2KUsageFix.java
 delete mode 100644 pgpainless-core/src/main/java/org/pgpainless/key/protection/fixes/package-info.java
 create mode 100644 pgpainless-core/src/main/kotlin/org/pgpainless/key/protection/fixes/S2KUsageFix.kt

diff --git a/pgpainless-core/src/main/java/org/pgpainless/key/protection/fixes/S2KUsageFix.java b/pgpainless-core/src/main/java/org/pgpainless/key/protection/fixes/S2KUsageFix.java
deleted file mode 100644
index 24fe533a..00000000
--- a/pgpainless-core/src/main/java/org/pgpainless/key/protection/fixes/S2KUsageFix.java
+++ /dev/null
@@ -1,92 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package org.pgpainless.key.protection.fixes;
-
-import org.bouncycastle.bcpg.SecretKeyPacket;
-import org.bouncycastle.openpgp.PGPException;
-import org.bouncycastle.openpgp.PGPPrivateKey;
-import org.bouncycastle.openpgp.PGPSecretKey;
-import org.bouncycastle.openpgp.PGPSecretKeyRing;
-import org.bouncycastle.openpgp.operator.PBESecretKeyEncryptor;
-import org.bouncycastle.openpgp.operator.PGPDigestCalculator;
-import org.pgpainless.algorithm.HashAlgorithm;
-import org.pgpainless.exception.WrongPassphraseException;
-import org.pgpainless.implementation.ImplementationFactory;
-import org.pgpainless.key.protection.SecretKeyRingProtector;
-import org.pgpainless.key.protection.UnlockSecretKey;
-
-/**
- * Repair class to fix keys which use S2K usage of value {@link SecretKeyPacket#USAGE_CHECKSUM}.
- * The method {@link #replaceUsageChecksumWithUsageSha1(PGPSecretKeyRing, SecretKeyRingProtector)} ensures
- * that such keys are encrypted using S2K usage {@link SecretKeyPacket#USAGE_SHA1} instead.
- *
- * @see <a href="https://github.com/pgpainless/pgpainless/issues/176">Related PGPainless Bug Report</a>
- * @see <a href="https://github.com/pgpainless/pgpainless/issues/178">Related PGPainless Feature Request</a>
- * @see <a href="https://github.com/bcgit/bc-java/issues/1020">Related upstream BC bug report</a>
- */
-public final class S2KUsageFix {
-
-    private S2KUsageFix() {
-
-    }
-
-    /**
-     * Repair method for keys which use S2K usage <pre>USAGE_CHECKSUM</pre> which is deemed insecure.
-     * This method fixes the private keys by changing them to <pre>USAGE_SHA1</pre> instead.
-     *
-     * @param keys keys
-     * @param protector protector to unlock and re-lock affected private keys
-     * @return fixed key ring
-     * @throws PGPException in case of a PGP error.
-     */
-    public static PGPSecretKeyRing replaceUsageChecksumWithUsageSha1(PGPSecretKeyRing keys, SecretKeyRingProtector protector) throws PGPException {
-        return replaceUsageChecksumWithUsageSha1(keys, protector, false);
-    }
-
-    /**
-     * Repair method for keys which use S2K usage <pre>USAGE_CHECKSUM</pre> which is deemed insecure.
-     * This method fixes the private keys by changing them to <pre>USAGE_SHA1</pre> instead.
-     *
-     * @param keys keys
-     * @param protector protector to unlock and re-lock affected private keys
-     * @param skipKeysWithMissingPassphrase if set to true, missing subkey passphrases will cause the subkey to stay unaffected.
-     * @return fixed key ring
-     * @throws PGPException in case of a PGP error.
-     */
-    public static PGPSecretKeyRing replaceUsageChecksumWithUsageSha1(PGPSecretKeyRing keys,
-                                                                     SecretKeyRingProtector protector,
-                                                                     boolean skipKeysWithMissingPassphrase) throws PGPException {
-        PGPDigestCalculator digestCalculator = ImplementationFactory.getInstance().getPGPDigestCalculator(HashAlgorithm.SHA1);
-        for (PGPSecretKey key : keys) {
-            // CHECKSUM is not recommended
-            if (key.getS2KUsage() != SecretKeyPacket.USAGE_CHECKSUM) {
-                continue;
-            }
-
-            long keyId = key.getKeyID();
-            PBESecretKeyEncryptor encryptor = protector.getEncryptor(keyId);
-            if (encryptor == null) {
-                if (skipKeysWithMissingPassphrase) {
-                    continue;
-                }
-                throw new WrongPassphraseException("Missing passphrase for key with ID " + Long.toHexString(keyId));
-            }
-
-            PGPPrivateKey privateKey = UnlockSecretKey.unlockSecretKey(key, protector);
-            // This constructor makes use of USAGE_SHA1 by default
-            PGPSecretKey fixedKey = new PGPSecretKey(
-                    privateKey,
-                    key.getPublicKey(),
-                    digestCalculator,
-                    key.isMasterKey(),
-                    protector.getEncryptor(keyId)
-            );
-
-            // replace the original key with the fixed one
-            keys = PGPSecretKeyRing.insertSecretKey(keys, fixedKey);
-        }
-        return keys;
-    }
-}
diff --git a/pgpainless-core/src/main/java/org/pgpainless/key/protection/fixes/package-info.java b/pgpainless-core/src/main/java/org/pgpainless/key/protection/fixes/package-info.java
deleted file mode 100644
index 06c299b1..00000000
--- a/pgpainless-core/src/main/java/org/pgpainless/key/protection/fixes/package-info.java
+++ /dev/null
@@ -1,8 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-/**
- * Secret Key Protection Fixes.
- */
-package org.pgpainless.key.protection.fixes;
diff --git a/pgpainless-core/src/main/kotlin/org/pgpainless/key/protection/fixes/S2KUsageFix.kt b/pgpainless-core/src/main/kotlin/org/pgpainless/key/protection/fixes/S2KUsageFix.kt
new file mode 100644
index 00000000..aeef0654
--- /dev/null
+++ b/pgpainless-core/src/main/kotlin/org/pgpainless/key/protection/fixes/S2KUsageFix.kt
@@ -0,0 +1,79 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.pgpainless.key.protection.fixes
+
+import org.bouncycastle.bcpg.SecretKeyPacket
+import org.bouncycastle.openpgp.PGPSecretKey
+import org.bouncycastle.openpgp.PGPSecretKeyRing
+import org.pgpainless.algorithm.HashAlgorithm
+import org.pgpainless.exception.WrongPassphraseException
+import org.pgpainless.implementation.ImplementationFactory
+import org.pgpainless.key.protection.SecretKeyRingProtector
+import org.pgpainless.key.protection.UnlockSecretKey.Companion.unlockSecretKey
+
+/**
+ * Repair class to fix keys which use S2K usage of value [SecretKeyPacket.USAGE_CHECKSUM].
+ * The method [replaceUsageChecksumWithUsageSha1] ensures that such keys are encrypted using
+ * S2K usage [SecretKeyPacket.USAGE_SHA1] instead.
+ *
+ * @see <a href="https://github.com/pgpainless/pgpainless/issues/176">Related PGPainless Bug Report</a>
+ * @see <a href="https://github.com/pgpainless/pgpainless/issues/178">Related PGPainless Feature Request</a>
+ * @see <a href="https://github.com/bcgit/bc-java/issues/1020">Related upstream BC bug report</a>
+ */
+class S2KUsageFix {
+
+    companion object {
+
+        /**
+         * Repair method for keys which use S2K usage <pre>USAGE_CHECKSUM</pre> which is deemed insecure.
+         * This method fixes the private keys by changing them to <pre>USAGE_SHA1</pre> instead.
+         *
+         * @param keys keys
+         * @param protector protector to unlock and re-lock affected private keys
+         * @param skipKeysWithMissingPassphrase if set to true, missing subkey passphrases will cause the subkey to stay unaffected.
+         * @return fixed key ring
+         * @throws PGPException in case of a PGP error.
+         */
+        @JvmStatic
+        @JvmOverloads
+        fun replaceUsageChecksumWithUsageSha1(
+                keys: PGPSecretKeyRing,
+                protector: SecretKeyRingProtector,
+                skipKeysWithMissingPassphrase: Boolean = false
+        ): PGPSecretKeyRing {
+            val digestCalculator = ImplementationFactory.getInstance().getPGPDigestCalculator(HashAlgorithm.SHA1)
+            val keyList = mutableListOf<PGPSecretKey>()
+            for (key in keys) {
+                // CHECKSUM is not recommended
+                if (key.s2KUsage != SecretKeyPacket.USAGE_CHECKSUM) {
+                    keyList.add(key)
+                    continue
+                }
+
+                val keyId = key.keyID
+                val encryptor = protector.getEncryptor(keyId)
+                if (encryptor == null) {
+                    if (skipKeysWithMissingPassphrase) {
+                        keyList.add(key)
+                        continue
+                    }
+                    throw WrongPassphraseException("Missing passphrase for key with ID " + java.lang.Long.toHexString(keyId))
+                }
+
+                val privateKey = unlockSecretKey(key, protector)
+                // This constructor makes use of USAGE_SHA1 by default
+                val fixedKey = PGPSecretKey(
+                        privateKey,
+                        key.publicKey,
+                        digestCalculator,
+                        key.isMasterKey,
+                        protector.getEncryptor(keyId)
+                )
+                keyList.add(fixedKey)
+            }
+            return PGPSecretKeyRing(keyList)
+        }
+    }
+}
\ No newline at end of file