pgpainless/pgpainless-core/src/main/kotlin/org/pgpainless/key/protection/fixes/S2KUsageFix.kt

86 lines
3.4 KiB
Kotlin

// 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.bouncycastle.extensions.unlock
import org.pgpainless.exception.WrongPassphraseException
import org.pgpainless.implementation.ImplementationFactory
import org.pgpainless.key.protection.SecretKeyRingProtector
/**
* 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 = key.unlock(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)
}
}
}