build.gradle

@@ -66,7 +66,7 @@ dependencies {
     implementation 'com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.17.0'
     implementation 'org.openapitools:jackson-databind-nullable:0.2.6'
     implementation 'org.apache.commons:commons-text:1.11.0'
-    implementation 'org.bouncycastle:bcpkix-jdk18on:1.76'
+    implementation 'net.java.dev.jna:jna:5.8.0'
     implementation 'org.modelmapper:modelmapper:3.2.0'
     implementation 'org.iban4j:iban4j:3.2.7-RELEASE'
     implementation 'org.springdoc:springdoc-openapi-starter-webmvc-ui:2.4.0'

src/main/java/net/hostsharing/hsadminng/hash/LinuxEtcShadowHashGenerator.java

@@ -6,8 +6,8 @@ import java.util.PriorityQueue;
 import java.util.Queue;
 import java.util.random.RandomGenerator;
 
-import org.bouncycastle.crypto.generators.OpenBSDBCrypt;
-
+import com.sun.jna.Library;
+import com.sun.jna.Native;
 
 public class LinuxEtcShadowHashGenerator {
 
@@ -15,13 +15,13 @@ public class LinuxEtcShadowHashGenerator {
     private static final Queue<String> predefinedSalts = new PriorityQueue<>();
 
     public static final int SALT_LENGTH = 16;
-    public static final int COST_FACTOR = 13;
 
     private final String plaintextPassword;
     private Algorithm algorithm;
 
     public enum Algorithm {
-        SHA512("6");
+        SHA512("6"),
+        YESCRYPT("y");
 
         final String prefix;
 
@@ -57,12 +57,12 @@ public class LinuxEtcShadowHashGenerator {
 
     void verify(final String givenHash) {
         final var parts = givenHash.split("\\$");
-        if (parts.length != 4) {
+        if (parts.length < 3 || parts.length > 5) {
             throw new IllegalArgumentException("not a " + algorithm.name() + " Linux hash: " + givenHash);
         }
 
         algorithm = Algorithm.byPrefix(parts[1]);
-        salt = parts[2];
+        salt = parts.length == 4 ? parts[2] : parts[2] + "$" + parts[3];
 
         if (!generate().equals(givenHash)) {
             throw new IllegalArgumentException("invalid password");
@@ -76,9 +76,8 @@ public class LinuxEtcShadowHashGenerator {
         if (plaintextPassword == null) {
             throw new IllegalStateException("no password given");
         }
-        final var hash = OpenBSDBCrypt.generate(plaintextPassword.toCharArray(), salt.getBytes(), COST_FACTOR);
-        final var hashedPassword = new String(org.bouncycastle.util.encoders.Base64.encode(hash.getBytes()));
-        return "$" + algorithm.prefix + "$" + salt + "$" + hashedPassword;
+
+        return NativeCryptLibrary.INSTANCE.crypt(plaintextPassword, "$" + algorithm.prefix + "$" + salt);
     }
 
     public static void nextSalt(final String salt) {
@@ -101,4 +100,13 @@ public class LinuxEtcShadowHashGenerator {
         }
         return withSalt(stringBuilder.toString());
     }
+    public static void main(String[] args) {
+        System.out.println(NativeCryptLibrary.INSTANCE.crypt("given password", "$6$abcdefghijklmno"));
+    }
+
+    public interface NativeCryptLibrary extends Library {
+        NativeCryptLibrary INSTANCE = Native.load("crypt", NativeCryptLibrary.class);
+
+        String crypt(String password, String salt);
+    }
 }

src/test/java/net/hostsharing/hsadminng/hash/LinuxEtcShadowHashGeneratorUnitTest.java

@@ -13,6 +13,20 @@ class LinuxEtcShadowHashGeneratorUnitTest {
     final String WRONG_PASSWORD = "wrong password";
     final String GIVEN_SALT = "0123456789abcdef";
 
+    // generated via mkpasswd for plaintext password GIVEN_PASSWORD (see above)
+    final String GIVEN_SHA512_HASH = "$6$ooei1HK6JXVaI7KC$sY5d9fEOr36hjh4CYwIKLMfRKL1539bEmbVCZ.zPiH0sv7jJVnoIXb5YEefEtoSM2WWgDi9hr7vXRe3Nw8zJP/";
+    final String GIVEN_YESCRYPT_HASH = "$y$j9T$wgYACPmBXvlMg2MzeZA0p1$KXUzd28nG.67GhPnBZ3aZsNNA5bWFdL/dyG4wS0iRw7";
+
+    @Test
+    void verifiesPasswordAgainstSha512HashFromMkpasswd() {
+        hash(GIVEN_PASSWORD).verify(GIVEN_SHA512_HASH); // throws exception if wrong
+    }
+
+    @Test
+    void verifiesPasswordAgainstYescryptHashFromMkpasswd() {
+        hash(GIVEN_PASSWORD).verify(GIVEN_YESCRYPT_HASH); // throws exception if wrong
+    }
+
     @Test
     void verifiesHashedPasswordWithRandomSalt() {
         final var hash = hash(GIVEN_PASSWORD).using(SHA512).withRandomSalt().generate();