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/*
* tinc app, an Android binding and user interface for the tinc mesh VPN daemon
* Copyright (C) 2017-2018 Pacien TRAN-GIRARD
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
package org.pacien.tincapp.utils
import org.bouncycastle.openssl.PEMException
import org.bouncycastle.openssl.PEMParser
import org.bouncycastle.openssl.jcajce.JcaPEMWriter
import org.bouncycastle.openssl.jcajce.JcePEMDecryptorProviderBuilder
import org.bouncycastle.openssl.jcajce.JcePEMEncryptorBuilder
import org.bouncycastle.util.encoders.Hex
import org.bouncycastle.util.io.pem.PemHeader
import org.bouncycastle.util.io.pem.PemObject
import java.io.File
import java.io.FileReader
import java.io.Writer
/**
* @author pacien
*/
object PemUtils {
private val PROVIDER = org.bouncycastle.jce.provider.BouncyCastleProvider()
private val ENCRYPTED_PROC_TYPE_HEADER = PemHeader("Proc-Type", "4,ENCRYPTED")
private val DEK_INFO_HEADER_KEY = "DEK-Info"
private val ALGO = "AES-256-CBC"
private class DekInfo(val algName: String, val iv: ByteArray)
private fun dekInfoHeader(iv: ByteArray) = PemHeader(DEK_INFO_HEADER_KEY, "$ALGO,${Hex.toHexString(iv)}")
private fun PemObject.getPemHeaders() = headers.map { it as PemHeader }
fun read(f: File): PemObject = PEMParser(FileReader(f)).readPemObject()
fun write(obj: PemObject, out: Writer) = JcaPEMWriter(out).apply { writeObject(obj) }.apply { close() }
fun isEncrypted(obj: PemObject) = obj.headers.contains(ENCRYPTED_PROC_TYPE_HEADER)
fun encrypt(obj: PemObject, passPhrase: String) =
JcePEMEncryptorBuilder(ALGO)
.setProvider(PROVIDER)
.build(passPhrase.toCharArray())
.let { PemObject(obj.type, listOf(ENCRYPTED_PROC_TYPE_HEADER, dekInfoHeader(it.iv)), it.encrypt(obj.content)) }
fun decrypt(obj: PemObject, passPhrase: String?) =
if (isEncrypted(obj)) {
val dekInfo = try {
obj.getPemHeaders()
.find { it.name == DEK_INFO_HEADER_KEY }!!
.value!!
.split(',')
.let { DekInfo(it[0], Hex.decode(it[1])) }
} catch (e: Exception) {
throw PEMException("Malformed DEK-Info header.", e)
}
JcePEMDecryptorProviderBuilder()
.setProvider(PROVIDER)
.build(passPhrase?.toCharArray())
.get(dekInfo.algName)
.decrypt(obj.content, dekInfo.iv)
.let { PemObject(obj.type, it) }
} else {
obj
}
}
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