IOS APP 防止抓包工具抓包

原文地址 https://lm1024.xyz/archives/34

看了这篇有关对 iOS app 进行安全加固看到防止http抓包后感觉自己能做一下实验。

分析

1、项目中能用到网络请求的地方一般都为调API接口、上传文件、加载文件、拉取图片几种情况。
2、第三方依赖库基础 AFNetwork SDWebImage。
3、第三方库源码分析。

• AFNetworking

- (instancetype)initWithSessionConfiguration:(NSURLSessionConfiguration *)configuration {
    self = [super init];
    if (!self) {
        return nil;
    }

    if (!configuration) {
        configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
    }

    self.sessionConfiguration = configuration;

    self.operationQueue = [[NSOperationQueue alloc] init];
    self.operationQueue.maxConcurrentOperationCount = 1;

    self.session = [NSURLSession sessionWithConfiguration:self.sessionConfiguration delegate:self delegateQueue:self.operationQueue];

    self.responseSerializer = [AFJSONResponseSerializer serializer];

    self.securityPolicy = [AFSecurityPolicy defaultPolicy];

#if !TARGET_OS_WATCH
    self.reachabilityManager = [AFNetworkReachabilityManager sharedManager];
#endif

    self.mutableTaskDelegatesKeyedByTaskIdentifier = [[NSMutableDictionary alloc] init];

    self.lock = [[NSLock alloc] init];
    self.lock.name = AFURLSessionManagerLockName;

    [self.session getTasksWithCompletionHandler:^(NSArray *dataTasks, NSArray *uploadTasks, NSArray *downloadTasks) {
        for (NSURLSessionDataTask *task in dataTasks) {
            [self addDelegateForDataTask:task uploadProgress:nil downloadProgress:nil completionHandler:nil];
        }

        for (NSURLSessionUploadTask *uploadTask in uploadTasks) {
            [self addDelegateForUploadTask:uploadTask progress:nil completionHandler:nil];
        }

        for (NSURLSessionDownloadTask *downloadTask in downloadTasks) {
            [self addDelegateForDownloadTask:downloadTask progress:nil destination:nil completionHandler:nil];
        }
    }];

    return self;
}

从这段代码中我们可以看出AFNetworking所有的session的产生都是self.session = [NSURLSession sessionWithConfiguration:self.sessionConfiguration delegate:self delegateQueue:self.operationQueue];这行代码负责产生

• SDWebImage
  SDWebImage负责将网络图片下载到本地并缓存的功能，那么我们只需要分析下载器相关的部分代码,从SDWebImageDownloader

- (void)createNewSessionWithConfiguration:(NSURLSessionConfiguration *)sessionConfiguration {
    [self cancelAllDownloads];

    if (self.session) {
        [self.session invalidateAndCancel];
    }

    sessionConfiguration.timeoutIntervalForRequest = self.downloadTimeout;

    /**
     *  Create the session for this task
     *  We send nil as delegate queue so that the session creates a serial operation queue for performing all delegate
     *  method calls and completion handler calls.
     */
    self.session = [NSURLSession sessionWithConfiguration:sessionConfiguration
                                                 delegate:self
                                            delegateQueue:nil];
}

从这段代码中能看出session也是由self.session = [NSURLSession sessionWithConfiguration:sessionConfiguration delegate:self delegateQueue:nil];这行代码产生。

解决方案

(1)只针对AFNetwork我们可以有
1、继承AFHTTPSessionManager在子类中重写- (instancetype)initWithSessionConfiguration:(NSURLSessionConfiguration *)configuration方法
2、hook - (instancetype)initWithSessionConfiguration:(NSURLSessionConfiguration *)configuration方法
3、hook + (NSURLSession *)sessionWithConfiguration:(NSURLSessionConfiguration *)configuration delegate:(nullable id <NSURLSessionDelegate>)delegate delegateQueue:(nullable NSOperationQueue *)queue;系统方法

(2)只针对SDWebImageView我们有
1、SDWebImageDownloader是一个单例，那么我们可以 直接设置[SDWebImageDownloader sharedDownloader].sessionConfiguration.connectionProxyDictionary = @{}
2、hook - (void)createNewSessionWithConfiguration:(NSURLSessionConfiguration *)sessionConfiguration
3、hook + (NSURLSession *)sessionWithConfiguration:(NSURLSessionConfiguration *)configuration delegate:(nullable id <NSURLSessionDelegate>)delegate delegateQueue:(nullable NSOperationQueue *)queue;系统方法

基于上面的情况和项目整体考虑采用了 + (NSURLSession *)sessionWithConfiguration:(NSURLSessionConfiguration *)configuration delegate:(nullable id <NSURLSessionDelegate>)delegate delegateQueue:(nullable NSOperationQueue *)queue;系统方法

源码

#import "NSURLSession+PLCategory.h"
#import <objc/runtime.h>

void swizzing(Class class, SEL originalSelector, SEL swizzledSelector)
{
    Method originalMethod = class_getClassMethod(class, originalSelector);
    Method swizzledMethod = class_getClassMethod(class, swizzledSelector);
    method_exchangeImplementations(originalMethod, swizzledMethod);
}
@implementation NSURLSession (QYCategory)

+ (void)load
{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        Class class = [NSURLSession class];
        swizzing(class, @selector(sessionWithConfiguration:), @selector(qy_sessionWithConfiguration:));

        swizzing(class, @selector(sessionWithConfiguration:delegate:delegateQueue:),
                 @selector(qy_sessionWithConfiguration:delegate:delegateQueue:));
    });
}

+ (NSURLSession *)qy_sessionWithConfiguration:(NSURLSessionConfiguration *)configuration
                                     delegate:(nullable id<NSURLSessionDelegate>)delegate
                                delegateQueue:(nullable NSOperationQueue *)queue
{
    if (!configuration)
    {
        configuration = [[NSURLSessionConfiguration alloc] init];
    }
    configuration.connectionProxyDictionary = @{};
    return [self pl_sessionWithConfiguration:configuration delegate:delegate delegateQueue:queue];
}

+ (NSURLSession *)qy_sessionWithConfiguration:(NSURLSessionConfiguration *)configuration
{
    if (configuration)
    {
        configuration.connectionProxyDictionary = @{};
    }
    return [self pl_sessionWithConfiguration:configuration];
}
@end