Spring Security架構(gòu)以及源碼詳析
前言
現(xiàn)在流行的通用授權(quán)框架有apache的shiro和Spring家族的Spring Security,在涉及今天的微服務(wù)鑒權(quán)時(shí),需要利用我們的授權(quán)框架搭建自己的鑒權(quán)服務(wù),今天總理了Spring Security。
Spring Security 主要實(shí)現(xiàn)了Authentication（認(rèn)證，解決who are you? ） 和 Access Control（訪問控制，也就是what are you allowed to do？，也稱為Authorization）。Spring Security在架構(gòu)上將認(rèn)證與授權(quán)分離，并提供了擴(kuò)展點(diǎn)。
核心對象
主要代碼在spring-security-core包下面。要了解Spring Security，需要先關(guān)注里面的核心對象。
SecurityContextHolder, SecurityContext 和 Authentication
SecurityContextHolder 是 SecurityContext的存放容器，默認(rèn)使用ThreadLocal 存儲(chǔ)，意味SecurityContext在相同線程中的方法都可用。
SecurityContext主要是存儲(chǔ)應(yīng)用的principal信息，在Spring Security中用Authentication 來表示。
獲取principal：
Object principal = SecurityContextHolder.getContext().getAuthentication().getPrincipal();
if (principal instanceof UserDetails) {
String username = ((UserDetails)principal).getUsername();
} else {
String username = principal.toString();
}
在Spring Security中，可以看一下Authentication定義：
public interface Authentication extends Principal, Serializable {
Collection<? extends GrantedAuthority> getAuthorities();
/**
* 通常是密碼
*/
Object getCredentials();
/**
* Stores additional details about the authentication request. These might be an IP
* address, certificate serial number etc.
*/
Object getDetails();
/**
* 用來標(biāo)識(shí)是否已認(rèn)證，如果使用用戶名和密碼登錄,通常是用戶名
*/
Object getPrincipal();
/**
* 是否已認(rèn)證
*/
boolean isAuthenticated();
void setAuthenticated(boolean isAuthenticated) throws IllegalArgumentException;
}
在實(shí)際應(yīng)用中，通常使用UsernamePasswordAuthenticationToken：
public abstract class AbstractAuthenticationToken implements Authentication,
CredentialsContainer {
}
public class UsernamePasswordAuthenticationToken extends AbstractAuthenticationToken {
}
一個(gè)常見的認(rèn)證過程通常是這樣的，創(chuàng)建一個(gè)UsernamePasswordAuthenticationToken，然后交給authenticationManager認(rèn)證（后面詳細(xì)說明），認(rèn)證通過則通過SecurityContextHolder存放Authentication信息。
UsernamePasswordAuthenticationToken authenticationToken = new UsernamePasswordAuthenticationToken(loginVM.getUsername(), loginVM.getPassword()); Authentication authentication = this.authenticationManager.authenticate(authenticationToken); SecurityContextHolder.getContext().setAuthentication(authentication);
UserDetails與UserDetailsService
UserDetails 是Spring Security里的一個(gè)關(guān)鍵接口，他用來表示一個(gè)principal。
public interface UserDetails extends Serializable {
/**
* 用戶的授權(quán)信息，可以理解為角色
*/
Collection<? extends GrantedAuthority> getAuthorities();
/**
* 用戶密碼
*
* @return the password
*/
String getPassword();
/**
* 用戶名
* */
String getUsername();
boolean isAccountNonExpired();
boolean isAccountNonLocked();
boolean isCredentialsNonExpired();
boolean isEnabled();
}
UserDetails提供了認(rèn)證所需的必要信息，在實(shí)際使用里，可以自己實(shí)現(xiàn)UserDetails，并增加額外的信息，比如email、mobile等信息。
在Authentication中的principal通常是用戶名，我們可以通過UserDetailsService來通過principal獲取UserDetails：
public interface UserDetailsService {
UserDetails loadUserByUsername(String username) throws UsernameNotFoundException;
}
GrantedAuthority
在UserDetails里說了，GrantedAuthority可以理解為角色，例如 ROLE_ADMINISTRATOR or ROLE_HR_SUPERVISOR。
小結(jié)
- SecurityContextHolder, 用來訪問 SecurityContext.
- SecurityContext, 用來存儲(chǔ)Authentication .
- Authentication, 代表憑證.
- GrantedAuthority, 代表權(quán)限.
- UserDetails, 用戶信息.
- UserDetailsService,獲取用戶信息.
Authentication認(rèn)證
AuthenticationManager
實(shí)現(xiàn)認(rèn)證主要是通過AuthenticationManager接口，它只包含了一個(gè)方法：
public interface AuthenticationManager {
Authentication authenticate(Authentication authentication)
throws AuthenticationException;
}
authenticate()方法主要做三件事：
- 如果驗(yàn)證通過，返回Authentication（通常帶上authenticated=true）。
- 認(rèn)證失敗拋出AuthenticationException
- 如果無法確定，則返回null
AuthenticationException是運(yùn)行時(shí)異常,它通常由應(yīng)用程序按通用方式處理，用戶代碼通常不用特意被捕獲和處理這個(gè)異常。
AuthenticationManager的默認(rèn)實(shí)現(xiàn)是ProviderManager，它委托一組AuthenticationProvider實(shí)例來實(shí)現(xiàn)認(rèn)證。
AuthenticationProvider和AuthenticationManager類似，都包含authenticate，但它有一個(gè)額外的方法supports，以允許查詢調(diào)用方是否支持給定Authentication類型：
public interface AuthenticationProvider {
Authentication authenticate(Authentication authentication)
throws AuthenticationException;
boolean supports(Class<?> authentication);
}
ProviderManager包含一組AuthenticationProvider，執(zhí)行authenticate時(shí)，遍歷Providers，然后調(diào)用supports，如果支持，則執(zhí)行遍歷當(dāng)前provider的authenticate方法，如果一個(gè)provider認(rèn)證成功，則break。
public Authentication authenticate(Authentication authentication)
throws AuthenticationException {
Class<? extends Authentication> toTest = authentication.getClass();
AuthenticationException lastException = null;
Authentication result = null;
boolean debug = logger.isDebugEnabled();
for (AuthenticationProvider provider : getProviders()) {
if (!provider.supports(toTest)) {
continue;
}
if (debug) {
logger.debug("Authentication attempt using "
+ provider.getClass().getName());
}
try {
result = provider.authenticate(authentication);
if (result != null) {
copyDetails(authentication, result);
break;
}
}
catch (AccountStatusException e) {
prepareException(e, authentication);
// SEC-546: Avoid polling additional providers if auth failure is due to
// invalid account status
throw e;
}
catch (InternalAuthenticationServiceException e) {
prepareException(e, authentication);
throw e;
}
catch (AuthenticationException e) {
lastException = e;
}
}
if (result == null && parent != null) {
// Allow the parent to try.
try {
result = parent.authenticate(authentication);
}
catch (ProviderNotFoundException e) {
// ignore as we will throw below if no other exception occurred prior to
// calling parent and the parent
// may throw ProviderNotFound even though a provider in the child already
// handled the request
}
catch (AuthenticationException e) {
lastException = e;
}
}
if (result != null) {
if (eraseCredentialsAfterAuthentication
&& (result instanceof CredentialsContainer)) {
// Authentication is complete. Remove credentials and other secret data
// from authentication
((CredentialsContainer) result).eraseCredentials();
}
eventPublisher.publishAuthenticationSuccess(result);
return result;
}
// Parent was null, or didn't authenticate (or throw an exception).
if (lastException == null) {
lastException = new ProviderNotFoundException(messages.getMessage(
"ProviderManager.providerNotFound",
new Object[] { toTest.getName() },
"No AuthenticationProvider found for {0}"));
}
prepareException(lastException, authentication);
throw lastException;
}
從上面的代碼可以看出， ProviderManager有一個(gè)可選parent，如果parent不為空，則調(diào)用parent.authenticate(authentication)
AuthenticationProvider
AuthenticationProvider有多種實(shí)現(xiàn)，大家最關(guān)注的通常是DaoAuthenticationProvider，繼承于AbstractUserDetailsAuthenticationProvider，核心是通過UserDetails來實(shí)現(xiàn)認(rèn)證,DaoAuthenticationProvider默認(rèn)會(huì)自動(dòng)加載，不用手動(dòng)配。
先來看AbstractUserDetailsAuthenticationProvider，看最核心的authenticate：
public Authentication authenticate(Authentication authentication)
throws AuthenticationException {
// 必須是UsernamePasswordAuthenticationToken
Assert.isInstanceOf(UsernamePasswordAuthenticationToken.class, authentication,
messages.getMessage(
"AbstractUserDetailsAuthenticationProvider.onlySupports",
"Only UsernamePasswordAuthenticationToken is supported"));
// 獲取用戶名
String username = (authentication.getPrincipal() == null) ? "NONE_PROVIDED"
: authentication.getName();
boolean cacheWasUsed = true;
// 從緩存獲取
UserDetails user = this.userCache.getUserFromCache(username);
if (user == null) {
cacheWasUsed = false;
try {
// retrieveUser 抽象方法，獲取用戶
user = retrieveUser(username,
(UsernamePasswordAuthenticationToken) authentication);
}
catch (UsernameNotFoundException notFound) {
logger.debug("User '" + username + "' not found");
if (hideUserNotFoundExceptions) {
throw new BadCredentialsException(messages.getMessage(
"AbstractUserDetailsAuthenticationProvider.badCredentials",
"Bad credentials"));
}
else {
throw notFound;
}
}
Assert.notNull(user,
"retrieveUser returned null - a violation of the interface contract");
}
try {
// 預(yù)先檢查，DefaultPreAuthenticationChecks，檢查用戶是否被lock或者賬號(hào)是否可用
preAuthenticationChecks.check(user);
// 抽象方法，自定義檢驗(yàn)
additionalAuthenticationChecks(user,
(UsernamePasswordAuthenticationToken) authentication);
}
catch (AuthenticationException exception) {
if (cacheWasUsed) {
// There was a problem, so try again after checking
// we're using latest data (i.e. not from the cache)
cacheWasUsed = false;
user = retrieveUser(username,
(UsernamePasswordAuthenticationToken) authentication);
preAuthenticationChecks.check(user);
additionalAuthenticationChecks(user,
(UsernamePasswordAuthenticationToken) authentication);
}
else {
throw exception;
}
}
// 后置檢查 DefaultPostAuthenticationChecks，檢查isCredentialsNonExpired
postAuthenticationChecks.check(user);
if (!cacheWasUsed) {
this.userCache.putUserInCache(user);
}
Object principalToReturn = user;
if (forcePrincipalAsString) {
principalToReturn = user.getUsername();
}
return createSuccessAuthentication(principalToReturn, authentication, user);
}
上面的檢驗(yàn)主要基于UserDetails實(shí)現(xiàn)，其中獲取用戶和檢驗(yàn)邏輯由具體的類去實(shí)現(xiàn)，默認(rèn)實(shí)現(xiàn)是DaoAuthenticationProvider，這個(gè)類的核心是讓開發(fā)者提供UserDetailsService來獲取UserDetails以及 PasswordEncoder來檢驗(yàn)密碼是否有效：
private UserDetailsService userDetailsService; private PasswordEncoder passwordEncoder;
看具體的實(shí)現(xiàn)，retrieveUser,直接調(diào)用userDetailsService獲取用戶：
protected final UserDetails retrieveUser(String username,
UsernamePasswordAuthenticationToken authentication)
throws AuthenticationException {
UserDetails loadedUser;
try {
loadedUser = this.getUserDetailsService().loadUserByUsername(username);
}
catch (UsernameNotFoundException notFound) {
if (authentication.getCredentials() != null) {
String presentedPassword = authentication.getCredentials().toString();
passwordEncoder.isPasswordValid(userNotFoundEncodedPassword,
presentedPassword, null);
}
throw notFound;
}
catch (Exception repositoryProblem) {
throw new InternalAuthenticationServiceException(
repositoryProblem.getMessage(), repositoryProblem);
}
if (loadedUser == null) {
throw new InternalAuthenticationServiceException(
"UserDetailsService returned null, which is an interface contract violation");
}
return loadedUser;
}
再來看驗(yàn)證：
protected void additionalAuthenticationChecks(UserDetails userDetails,
UsernamePasswordAuthenticationToken authentication)
throws AuthenticationException {
Object salt = null;
if (this.saltSource != null) {
salt = this.saltSource.getSalt(userDetails);
}
if (authentication.getCredentials() == null) {
logger.debug("Authentication failed: no credentials provided");
throw new BadCredentialsException(messages.getMessage(
"AbstractUserDetailsAuthenticationProvider.badCredentials",
"Bad credentials"));
}
// 獲取用戶密碼
String presentedPassword = authentication.getCredentials().toString();
// 比較passwordEncoder后的密碼是否和userdetails的密碼一致
if (!passwordEncoder.isPasswordValid(userDetails.getPassword(),
presentedPassword, salt)) {
logger.debug("Authentication failed: password does not match stored value");
throw new BadCredentialsException(messages.getMessage(
"AbstractUserDetailsAuthenticationProvider.badCredentials",
"Bad credentials"));
}
}
小結(jié)：要自定義認(rèn)證，使用DaoAuthenticationProvider，只需要為其提供PasswordEncoder和UserDetailsService就可以了。
定制 Authentication Managers
Spring Security提供了一個(gè)Builder類AuthenticationManagerBuilder，借助它可以快速實(shí)現(xiàn)自定義認(rèn)證。
看官方源碼說明：
SecurityBuilder used to create an AuthenticationManager . Allows for easily building in memory authentication, LDAP authentication, JDBC based authentication, adding UserDetailsService , and adding AuthenticationProvider's.
AuthenticationManagerBuilder可以用來Build一個(gè)AuthenticationManager，可以創(chuàng)建基于內(nèi)存的認(rèn)證、LDAP認(rèn)證、 JDBC認(rèn)證，以及添加UserDetailsService和AuthenticationProvider。
簡單使用：
@Configuration
@EnableWebSecurity
@EnableGlobalMethodSecurity(prePostEnabled = true, securedEnabled = true)
public class ApplicationSecurity extends WebSecurityConfigurerAdapter {
public SecurityConfiguration(AuthenticationManagerBuilder authenticationManagerBuilder, UserDetailsService userDetailsService,TokenProvider tokenProvider,CorsFilter corsFilter, SecurityProblemSupport problemSupport) {
this.authenticationManagerBuilder = authenticationManagerBuilder;
this.userDetailsService = userDetailsService;
this.tokenProvider = tokenProvider;
this.corsFilter = corsFilter;
this.problemSupport = problemSupport;
}
@PostConstruct
public void init() {
try {
authenticationManagerBuilder
.userDetailsService(userDetailsService)
.passwordEncoder(passwordEncoder());
} catch (Exception e) {
throw new BeanInitializationException("Security configuration failed", e);
}
}
@Override
protected void configure(HttpSecurity http) throws Exception {
http
.addFilterBefore(corsFilter, UsernamePasswordAuthenticationFilter.class)
.exceptionHandling()
.authenticationEntryPoint(problemSupport)
.accessDeniedHandler(problemSupport)
.and()
.csrf()
.disable()
.headers()
.frameOptions()
.disable()
.and()
.sessionManagement()
.sessionCreationPolicy(SessionCreationPolicy.STATELESS)
.and()
.authorizeRequests()
.antMatchers("/api/register").permitAll()
.antMatchers("/api/activate").permitAll()
.antMatchers("/api/authenticate").permitAll()
.antMatchers("/api/account/reset-password/init").permitAll()
.antMatchers("/api/account/reset-password/finish").permitAll()
.antMatchers("/api/profile-info").permitAll()
.antMatchers("/api/**").authenticated()
.antMatchers("/management/health").permitAll()
.antMatchers("/management/**").hasAuthority(AuthoritiesConstants.ADMIN)
.antMatchers("/v2/api-docs/**").permitAll()
.antMatchers("/swagger-resources/configuration/ui").permitAll()
.antMatchers("/swagger-ui/index.html").hasAuthority(AuthoritiesConstants.ADMIN)
.and()
.apply(securityConfigurerAdapter());
}
}
授權(quán)與訪問控制
一旦認(rèn)證成功，我們可以繼續(xù)進(jìn)行授權(quán)，授權(quán)是通過AccessDecisionManager來實(shí)現(xiàn)的?？蚣苡腥N實(shí)現(xiàn)，默認(rèn)是AffirmativeBased，通過AccessDecisionVoter決策，有點(diǎn)像ProviderManager委托給AuthenticationProviders來認(rèn)證。
public void decide(Authentication authentication, Object object,
Collection<ConfigAttribute> configAttributes) throws AccessDeniedException {
int deny = 0;
// 遍歷DecisionVoter
for (AccessDecisionVoter voter : getDecisionVoters()) {
// 投票
int result = voter.vote(authentication, object, configAttributes);
if (logger.isDebugEnabled()) {
logger.debug("Voter: " + voter + ", returned: " + result);
}
switch (result) {
case AccessDecisionVoter.ACCESS_GRANTED:
return;
case AccessDecisionVoter.ACCESS_DENIED:
deny++;
break;
default:
break;
}
}
// 一票否決
if (deny > 0) {
throw new AccessDeniedException(messages.getMessage(
"AbstractAccessDecisionManager.accessDenied", "Access is denied"));
}
// To get this far, every AccessDecisionVoter abstained
checkAllowIfAllAbstainDecisions();
}
來看AccessDecisionVoter：
boolean supports(ConfigAttribute attribute); boolean supports(Class<?> clazz); int vote(Authentication authentication, S object, Collection<ConfigAttribute> attributes);
object是用戶要訪問的資源，ConfigAttribute則是訪問object要滿足的條件，通常payload是字符串，比如ROLE_ADMIN 。所以我們來看下RoleVoter的實(shí)現(xiàn)，其核心就是從authentication提取出GrantedAuthority，然后和ConfigAttribute比較是否滿足條件。
public boolean supports(ConfigAttribute attribute) {
if ((attribute.getAttribute() != null)
&& attribute.getAttribute().startsWith(getRolePrefix())) {
return true;
}
else {
return false;
}
}
public boolean supports(Class<?> clazz) {
return true;
}
public int vote(Authentication authentication, Object object,
Collection<ConfigAttribute> attributes) {
if(authentication == null) {
return ACCESS_DENIED;
}
int result = ACCESS_ABSTAIN;
// 獲取GrantedAuthority信息
Collection<? extends GrantedAuthority> authorities = extractAuthorities(authentication);
for (ConfigAttribute attribute : attributes) {
if (this.supports(attribute)) {
// 默認(rèn)拒絕訪問
result = ACCESS_DENIED;
// Attempt to find a matching granted authority
for (GrantedAuthority authority : authorities) {
// 判斷是否有匹配的 authority
if (attribute.getAttribute().equals(authority.getAuthority())) {
// 可訪問
return ACCESS_GRANTED;
}
}
}
}
return result;
}
這里要疑問，ConfigAttribute哪來的？其實(shí)就是上面ApplicationSecurity的configure里的。
web security 如何實(shí)現(xiàn)
Web層中的Spring Security（用于UI和HTTP后端）基于Servlet Filters，下圖顯示了單個(gè)HTTP請求的處理程序的典型分層。
Spring Security通過FilterChainProxy作為單一的Filter注冊到web層，Proxy內(nèi)部的Filter。
FilterChainProxy相當(dāng)于一個(gè)filter的容器，通過VirtualFilterChain來依次調(diào)用各個(gè)內(nèi)部filter
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
boolean clearContext = request.getAttribute(FILTER_APPLIED) == null;
if (clearContext) {
try {
request.setAttribute(FILTER_APPLIED, Boolean.TRUE);
doFilterInternal(request, response, chain);
}
finally {
SecurityContextHolder.clearContext();
request.removeAttribute(FILTER_APPLIED);
}
}
else {
doFilterInternal(request, response, chain);
}
}
private void doFilterInternal(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
FirewalledRequest fwRequest = firewall
.getFirewalledRequest((HttpServletRequest) request);
HttpServletResponse fwResponse = firewall
.getFirewalledResponse((HttpServletResponse) response);
List<Filter> filters = getFilters(fwRequest);
if (filters == null || filters.size() == 0) {
if (logger.isDebugEnabled()) {
logger.debug(UrlUtils.buildRequestUrl(fwRequest)
+ (filters == null ? " has no matching filters"
: " has an empty filter list"));
}
fwRequest.reset();
chain.doFilter(fwRequest, fwResponse);
return;
}
VirtualFilterChain vfc = new VirtualFilterChain(fwRequest, chain, filters);
vfc.doFilter(fwRequest, fwResponse);
}
private static class VirtualFilterChain implements FilterChain {
private final FilterChain originalChain;
private final List<Filter> additionalFilters;
private final FirewalledRequest firewalledRequest;
private final int size;
private int currentPosition = 0;
private VirtualFilterChain(FirewalledRequest firewalledRequest,
FilterChain chain, List<Filter> additionalFilters) {
this.originalChain = chain;
this.additionalFilters = additionalFilters;
this.size = additionalFilters.size();
this.firewalledRequest = firewalledRequest;
}
public void doFilter(ServletRequest request, ServletResponse response)
throws IOException, ServletException {
if (currentPosition == size) {
if (logger.isDebugEnabled()) {
logger.debug(UrlUtils.buildRequestUrl(firewalledRequest)
+ " reached end of additional filter chain; proceeding with original chain");
}
// Deactivate path stripping as we exit the security filter chain
this.firewalledRequest.reset();
originalChain.doFilter(request, response);
}
else {
currentPosition++;
Filter nextFilter = additionalFilters.get(currentPosition - 1);
if (logger.isDebugEnabled()) {
logger.debug(UrlUtils.buildRequestUrl(firewalledRequest)
+ " at position " + currentPosition + " of " + size
+ " in additional filter chain; firing Filter: '"
+ nextFilter.getClass().getSimpleName() + "'");
}
nextFilter.doFilter(request, response, this);
}
}
}
參考
https://spring.io/guides/topicals/spring-security-architecture/
https://docs.spring.io/spring-security/site/docs/5.0.5.RELEASE/reference/htmlsingle/#overall-architecture
總結(jié)
以上就是這篇文章的全部內(nèi)容了，希望本文的內(nèi)容對大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值，如果有疑問大家可以留言交流，謝謝大家對腳本之家的支持。
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