increase minimum password strength

pom.xml

@@ -409,6 +409,11 @@
 				</exclusion>
 			</exclusions>
 		</dependency>
+		<dependency>
+			<groupId>org.passay</groupId>
+			<artifactId>passay</artifactId>
+			<version>1.6.1</version>
+		</dependency>
 
 		<dependency>
 			<groupId>redis.clients</groupId>

src/main/java/com/commafeed/backend/service/UserService.java

@@ -92,19 +92,9 @@ public User register(String name, String password, String email, Collection<Role
 
 	public User register(String name, String password, String email, Collection<Role> roles, boolean forceRegistration) {
 
-		Preconditions.checkNotNull(name);
-		Preconditions.checkArgument(StringUtils.length(name) <= 32, "Name too long (32 characters maximum)");
-		Preconditions.checkNotNull(password);
-
 		if (!forceRegistration) {
 			Preconditions.checkState(config.getApplicationSettings().getAllowRegistrations(),
 					"Registrations are closed on this CommaFeed instance");
-
-			Preconditions.checkNotNull(email);
-			Preconditions.checkArgument(StringUtils.length(name) >= 3, "Name too short (3 characters minimum)");
-			Preconditions.checkArgument(forceRegistration || StringUtils.length(password) >= 6,
-					"Password too short (6 characters maximum)");
-			Preconditions.checkArgument(StringUtils.contains(email, "@"), "Invalid email address");
 		}
 
 		Preconditions.checkArgument(userDAO.findByName(name) == null, "Name already taken");

src/main/java/com/commafeed/frontend/auth/PasswordConstraintValidator.java

@@ -0,0 +1,54 @@
+package com.commafeed.frontend.auth;
+
+import java.util.List;
+
+import javax.validation.ConstraintValidator;
+import javax.validation.ConstraintValidatorContext;
+
+import org.passay.CharacterRule;
+import org.passay.EnglishCharacterData;
+import org.passay.LengthRule;
+import org.passay.PasswordData;
+import org.passay.PasswordValidator;
+import org.passay.RuleResult;
+import org.passay.WhitespaceRule;
+
+public class PasswordConstraintValidator implements ConstraintValidator<ValidPassword, String> {
+
+	@Override
+	public void initialize(ValidPassword constraintAnnotation) {
+		// nothing to do
+	}
+
+	@Override
+	public boolean isValid(String value, ConstraintValidatorContext context) {
+		PasswordValidator validator = buildPasswordValidator();
+		RuleResult result = validator.validate(new PasswordData(value));
+
+		if (result.isValid()) {
+			return true;
+		}
+
+		List<String> messages = validator.getMessages(result);
+		String message = String.join(System.lineSeparator(), messages);
+		context.buildConstraintViolationWithTemplate(message).addConstraintViolation().disableDefaultConstraintViolation();
+		return false;
+	}
+
+	private PasswordValidator buildPasswordValidator() {
+		return new PasswordValidator(
+				// length
+				new LengthRule(8, 128),
+				// 1 uppercase char
+				new CharacterRule(EnglishCharacterData.UpperCase, 1),
+				// 1 lowercase char
+				new CharacterRule(EnglishCharacterData.LowerCase, 1),
+				// 1 digit
+				new CharacterRule(EnglishCharacterData.Digit, 1),
+				// 1 special char
+				new CharacterRule(EnglishCharacterData.Special, 1),
+				// no whitespace
+				new WhitespaceRule());
+	}
+
+}

src/main/java/com/commafeed/frontend/auth/ValidPassword.java

@@ -0,0 +1,23 @@
+package com.commafeed.frontend.auth;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import javax.validation.Constraint;
+import javax.validation.Payload;
+
+@Documented
+@Constraint(validatedBy = PasswordConstraintValidator.class)
+@Target({ ElementType.TYPE, ElementType.FIELD, ElementType.ANNOTATION_TYPE })
+@Retention(RetentionPolicy.RUNTIME)
+public @interface ValidPassword {
+
+	String message() default "Invalid Password";
+
+	Class<?>[] groups() default {};
+
+	Class<? extends Payload>[] payload() default {};
+}

src/main/java/com/commafeed/frontend/model/request/ProfileModificationRequest.java

@@ -2,6 +2,8 @@
 
 import java.io.Serializable;
 
+import com.commafeed.frontend.auth.ValidPassword;
+
 import io.swagger.annotations.ApiModel;
 import io.swagger.annotations.ApiModelProperty;
 import lombok.Data;
@@ -15,6 +17,7 @@ public class ProfileModificationRequest implements Serializable {
 	private String email;
 
 	@ApiModelProperty(value = "changes password of the user, if specified")
+	@ValidPassword
 	private String password;
 
 	@ApiModelProperty(value = "generate a new api key")

src/main/java/com/commafeed/frontend/model/request/RegistrationRequest.java

@@ -6,6 +6,8 @@
 import org.hibernate.validator.constraints.Length;
 import org.hibernate.validator.constraints.NotEmpty;
 
+import com.commafeed.frontend.auth.ValidPassword;
+
 import io.swagger.annotations.ApiModel;
 import io.swagger.annotations.ApiModelProperty;
 import lombok.Data;
@@ -21,7 +23,7 @@ public class RegistrationRequest implements Serializable {
 	private String name;
 
 	@ApiModelProperty(value = "password, minimum 6 characters", required = true)
-	@Length(min = 6)
+	@ValidPassword
 	@NotEmpty
 	private String password;
 

src/main/java/com/commafeed/frontend/resource/UserREST.java

@@ -192,8 +192,7 @@ public Response getUserProfile(@ApiParam(hidden = true) @SecurityCheck User user
 	@ApiOperation(value = "Save user's profile")
 	@Timed
 	public Response saveUserProfile(@ApiParam(hidden = true) @SecurityCheck User user,
-			@ApiParam(required = true) ProfileModificationRequest request) {
-		Preconditions.checkArgument(StringUtils.isBlank(request.getPassword()) || request.getPassword().length() >= 6);
+			@Valid @ApiParam(required = true) ProfileModificationRequest request) {
 		if (StringUtils.isNotBlank(request.getEmail())) {
 			User u = userDAO.findByEmail(request.getEmail());
 			Preconditions.checkArgument(u == null || user.getId().equals(u.getId()));