HHH-19471 - Hashing a constraint name using SHA-256 if the MD5 algorithm is not available

Co-authored-by: Yitzchak Weiser <[email protected]>
Co-authored-by: Ashwinkumar Rathod <[email protected]>

Author: 3 people

hibernate-core/src/main/java/org/hibernate/boot/model/naming/NamingHelper.java

@@ -12,6 +12,7 @@
 import java.util.List;
 
 import org.hibernate.HibernateException;
+import org.jboss.logging.Logger;
 
 import static java.util.Comparator.comparing;
 
@@ -30,6 +31,8 @@ public static NamingHelper withCharset(String charset) {
 
 	private final String charset;
 
+	private static final Logger log = Logger.getLogger(NamingHelper.class);
+
 	public NamingHelper() {
 		this(null);
 	}
@@ -124,8 +127,8 @@ public String generateHashedConstraintName(
 	}
 
 	/**
-	 * Hash a constraint name using MD5. Convert the MD5 digest to base 35
-	 * (full alphanumeric), guaranteeing
+	 * Hash a constraint name using MD5. If MD5 is not available, fall back to SHA-256.
+	 * Convert the digest to base 35 (full alphanumeric), guaranteeing
 	 * that the length of the name will always be smaller than the 30
 	 * character identifier restriction enforced by a few dialects.
 	 *
@@ -135,17 +138,36 @@ public String generateHashedConstraintName(
 	 */
 	public String hashedName(String name) {
 		try {
-			final MessageDigest md5 = MessageDigest.getInstance( "MD5" );
-			md5.reset();
-			md5.update( charset != null ? name.getBytes( charset ) : name.getBytes() );
-			final BigInteger bigInt = new BigInteger( 1, md5.digest() );
-			// By converting to base 35 (full alphanumeric), we guarantee
-			// that the length of the name will always be smaller than the 30
-			// character identifier restriction enforced by a few dialects.
-			return bigInt.toString( 35 );
+			return hashWithAlgorithm(name, "MD5");
 		}
-		catch ( NoSuchAlgorithmException | UnsupportedEncodingException e ) {
-			throw new HibernateException( "Unable to generate a hashed name", e );
+		catch (NoSuchAlgorithmException | UnsupportedEncodingException e) {
+			log.warnf("MD5 algorithm failed for hashedName, falling back to SHA-256: %s", e.getMessage());
+			try {
+				return hashWithAlgorithm(name, "SHA-256");
+			}
+			catch (NoSuchAlgorithmException | UnsupportedEncodingException ex) {
+				throw new HibernateException("Unable to generate a hashed name", ex);
+			}
 		}
 	}
+
+	/**
+	 * Helper to hash a name with the given algorithm and convert to base 35.
+	 *
+	 * @param name The name to be hashed.
+	 * @param algorithm The hashing algorithm to use.
+	 *
+	 * @return String The hashed name.
+	 */
+	public String hashWithAlgorithm(String name, String algorithm)
+			throws NoSuchAlgorithmException, UnsupportedEncodingException {
+		final MessageDigest md = MessageDigest.getInstance(algorithm);
+		md.reset();
+		md.update( charset != null ? name.getBytes( charset ) : name.getBytes() );
+		final BigInteger bigInt = new BigInteger( 1, md.digest() );
+		// By converting to base 35 (full alphanumeric), we guarantee
+		// that the length of the name will always be smaller than the 30
+		// character identifier restriction enforced by a few dialects.
+		return bigInt.toString( 35 );
+	}
 }

hibernate-core/src/test/java/org/hibernate/orm/test/bootstrap/binding/naming/NamingHelperTest.java

@@ -9,13 +9,17 @@
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
+import org.junit.jupiter.api.Test;
 
 import java.nio.charset.StandardCharsets;
+import java.io.UnsupportedEncodingException;
+import java.security.NoSuchAlgorithmException;
 import java.util.List;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.*;
 
 class NamingHelperTest {
 
@@ -57,6 +61,51 @@ void smoke(String charset, String prefix, String tableName, String referencedTab
 				.isEqualTo( expectedConstraintName );
 	}
 
+	@Test
+	void testHashWithAlgorithm_md5_utf8() throws Exception {
+		NamingHelper helper = NamingHelper.withCharset(StandardCharsets.UTF_8.name());
+		String hash = helper.hashWithAlgorithm("table_name", "MD5");
+		assertNotNull(hash);
+		assertFalse(hash.isEmpty());
+		// MD5 hash of "table_name" in base 35 should be deterministic
+		assertEquals("8q6ok4ne4ufel54crtitkq7ir", hash);
+	}
+
+	@Test
+	void testHashWithAlgorithm_sha256_utf8() throws Exception {
+		NamingHelper helper = NamingHelper.withCharset(StandardCharsets.UTF_8.name());
+		String hash = helper.hashWithAlgorithm("table_name", "SHA-256");
+		assertNotNull(hash);
+		assertFalse(hash.isEmpty());
+		// SHA-256 hash of "table_name" in base 35 should be deterministic
+		assertEquals("nie2bx5e7mderevrnl4gkuhtmy45nwfvst7dv6cx3pb3yy9ul1", hash);
+	}
+
+	@Test
+	void testHashWithAlgorithm_md5_iso88591() throws Exception {
+		NamingHelper helper = NamingHelper.withCharset(StandardCharsets.ISO_8859_1.name());
+		String hash = helper.hashWithAlgorithm("café", "MD5");
+		assertNotNull(hash);
+		assertFalse(hash.isEmpty());
+		assertEquals("hgll69c0qdhsjikniholqfcj4", hash);
+	}
+
+	@Test
+	void testHashWithAlgorithm_invalidAlgorithm() {
+		NamingHelper helper = NamingHelper.withCharset(StandardCharsets.UTF_8.name());
+		assertThrows(NoSuchAlgorithmException.class, () -> {
+			helper.hashWithAlgorithm("table_name", "NOPE");
+		});
+	}
+
+	@Test
+	void testHashWithAlgorithm_invalidCharset() {
+		NamingHelper helper = NamingHelper.withCharset("NOPE-CHARSET");
+		assertThrows(UnsupportedEncodingException.class, () -> {
+			helper.hashWithAlgorithm("table_name", "MD5");
+		});
+	}
+
 	private static Stream<Arguments> args() {
 		// String charset, String prefix, String tableName, String referencedTableName,
 		// List<String> columnNames, String expectedFkName, String expectedConstraintName