Spring Boot中AuthenticationManager.authenticate方法触发栈溢出问题排查

问题场景 #

配置Spring Security配置类后，发现authenticationConfiguration.getAuthenticationManager()返回null，且在AuthController调用authenticationManager.authenticate()时触发栈溢出错误。

SecurityConfig代码 #

package com.example.demo.security;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.config.annotation.authentication.configuration.AuthenticationConfiguration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.http.SessionCreationPolicy;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.security.provisioning.InMemoryUserDetailsManager;
import org.springframework.security.web.SecurityFilterChain;
import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;

@Configuration
@EnableWebSecurity
public class SecurityConfig {

    private JwtAuthEntryPoint authEntryPoint;
    private CustomUserDetailsService userDetailsService;
    
    @Autowired
    public SecurityConfig(CustomUserDetailsService userDetailsService, JwtAuthEntryPoint authEntryPoint) {
        this.userDetailsService = userDetailsService;
        this.authEntryPoint = authEntryPoint;
    }

    @Bean
    public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
        http
                .csrf().disable()
                .exceptionHandling()
                .authenticationEntryPoint(authEntryPoint)
                .and()
                .sessionManagement()
                .sessionCreationPolicy(SessionCreationPolicy.STATELESS)
                .and()
                .authorizeHttpRequests()
                .requestMatchers("/**").permitAll()
                .anyRequest().authenticated()
                .and()
                .httpBasic();
        http.addFilterBefore(jwtAuthenticationFilter(), UsernamePasswordAuthenticationFilter.class);
        return http.build();
    }

    @Bean
    public UserDetailsService users() {
        UserDetails admin = User.builder()
                .username("admin")
                .password("")
                .roles("ADMIN")
                .build();

        return new InMemoryUserDetailsManager(admin);
    }

    @Bean
    public AuthenticationManager authenticationManager(
            AuthenticationConfiguration authenticationConfiguration) throws Exception {
        return authenticationConfiguration.getAuthenticationManager();
    }

    @Bean
    PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }

    @Bean
    public JWTAuthenticationFilter jwtAuthenticationFilter() {
        return new JWTAuthenticationFilter();
    }
}

AuthController代码 #

@RestController
@RequestMapping("/auth")
public class AuthController {
    @Autowired
    private AuthenticationManager authenticationManager;
    private UserRepository userRepository;
    private RoleRepository roleRepository;
    private PasswordEncoder passwordEncoder;
    private JWTGenerator jwtGenerator;

    @Autowired
    public AuthController(AuthenticationManager authenticationManager, UserRepository userRepository,
                          RoleRepository roleRepository, PasswordEncoder passwordEncoder, JWTGenerator jwtGenerator) {
        this.authenticationManager = authenticationManager;
        this.userRepository = userRepository;
        this.roleRepository = roleRepository;
        this.passwordEncoder = passwordEncoder;
        this.jwtGenerator = jwtGenerator;
    }

    @PostMapping("/login")
    public ResponseEntity<?> login(@RequestBody User user){
        Authentication authentication = this.authenticationManager.authenticate(
                new UsernamePasswordAuthenticationToken(
                        user.getUsername(),
                        user.getPassword()));
        SecurityContextHolder.getContext().setAuthentication(authentication);
        String token = jwtGenerator.generateToken(authentication);
        return new ResponseEntity<>(HttpStatus.OK);
    }
}

问题根源 #

1. UserDetailsService Bean冲突：配置类中同时注入了CustomUserDetailsService，又定义了users()方法返回InMemoryUserDetailsManager，容器中存在两个UserDetailsService实例，导致AuthenticationConfiguration无法确定依赖，无法正确初始化AuthenticationManager，出现返回null的情况。
2. 密码未加密：InMemory用户的密码是空字符串且未经过BCryptPasswordEncoder加密，认证时密码校验不通过，触发异常处理逻辑，结合AuthenticationManager的初始化异常，最终引发循环调用导致栈溢出。
3. 过滤器潜在循环调用：如果JWTAuthenticationFilter内部存在触发认证的逻辑，结合AuthenticationManager的异常状态，可能形成循环调用链条，加剧栈溢出问题。

解决步骤 #

1. 删除重复的UserDetailsService Bean：移除SecurityConfig中的users()方法，让Spring使用注入的CustomUserDetailsService作为唯一的用户详情服务实现。
2. 修复密码加密逻辑：如果需要保留InMemory用户，必须用配置的PasswordEncoder加密密码，示例代码：

   // 替换原users()方法中的密码设置
   .password(passwordEncoder().encode("your-admin-password"))
   

3. 验证AuthenticationManager初始化：移除冲突Bean后，AuthenticationConfiguration会自动关联正确的UserDetailsService，getAuthenticationManager()将返回有效实例。
4. 检查JWT过滤器逻辑：确保JWTAuthenticationFilter中没有重复调用authenticationManager.authenticate()，避免触发循环认证流程。

内容的提问来源于stack exchange，提问作者felipebubu