iOS开发基础109-网络安全

在iOS开发中，保障应用的网络安全是一个非常重要的环节。以下是一些常见的网络安全措施及对应的示例代码：

Swift版

1. 使用HTTPS

确保所有的网络请求使用HTTPS协议，以加密数据传输，防止中间人攻击。

示例代码：

在Info.plist中配置App Transport Security (ATS)：

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSAllowsArbitraryLoads</key>
    <false/>
</dict>

2. SSL Pinning

通过SSL Pinning可以确保应用程序只信任指定的服务器证书，防止被劫持到伪造的服务器。

示例代码：

import Foundation

class URLSessionPinningDelegate: NSObject, URLSessionDelegate {
  func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
        if let serverTrust = challenge.protectionSpace.serverTrust,
           SecTrustEvaluate(serverTrust, nil) == errSecSuccess,
           let serverCertificate = SecTrustGetCertificateAtIndex(serverTrust, 0) {

            let localCertificateData = try? Data(contentsOf: Bundle.main.url(forResource: "your_cert", withExtension: "cer")!)
            let serverCertificateData = SecCertificateCopyData(serverCertificate) as Data

            if localCertificateData == serverCertificateData {
                let credential = URLCredential(trust: serverTrust)
                completionHandler(.useCredential, credential)
                return
            }
        }
        completionHandler(.cancelAuthenticationChallenge, nil)
  }
}

// Usage
let url = URL(string: "https://yoursecurewebsite.com")!
let session = URLSession(configuration: .default, delegate: URLSessionPinningDelegate(), delegateQueue: nil)
let task = session.dataTask(with: url) { data, response, error in
    // Handle response
}
task.resume()

3. 防止SQL注入

在处理用户输入时，使用参数化查询来防止SQL注入攻击。

示例代码：

import SQLite3

func queryDatabase(userInput: String) {
    var db: OpaquePointer?
    // Open database (assuming dbPath is the path to your database)
    sqlite3_open(dbPath, &db)

    var queryStatement: OpaquePointer?
    let query = "SELECT * FROM users WHERE username = ?"
    
    if sqlite3_prepare_v2(db, query, -1, &queryStatement, nil) == SQLITE_OK {
        sqlite3_bind_text(queryStatement, 1, userInput, -1, nil)
        
        while sqlite3_step(queryStatement) == SQLITE_ROW {
            // Process results
        }
    }
    
    sqlite3_finalize(queryStatement)
    sqlite3_close(db)
}

4. Data Encryption

在存储敏感数据时，使用iOS的加密库来加密数据，比如使用Keychain。

示例代码：

import Security

func saveToKeychain(key: String, data: Data) -> OSStatus {
    let query: [String: Any] = [
        kSecClass as String: kSecClassGenericPassword,
        kSecAttrAccount as String: key,
        kSecValueData as String: data
    ]

    SecItemDelete(query as CFDictionary) // Delete any existing item
    return SecItemAdd(query as CFDictionary, nil) // Add new item
}

func loadFromKeychain(key: String) -> Data? {
    let query: [String: Any] = [
        kSecClass as String: kSecClassGenericPassword,
        kSecAttrAccount as String: key,
        kSecReturnData as String: kCFBooleanTrue!,
        kSecMatchLimit as String: kSecMatchLimitOne
    ]

    var dataTypeRef: AnyObject?
    let status: OSStatus = SecItemCopyMatching(query as CFDictionary, &dataTypeRef)

    if status == noErr {
        return dataTypeRef as? Data
    } else {
        return nil
    }
}

5. 输入验证与清理

对用户输入进行验证和清理，防止XSS（跨站脚本攻击）和其他注入攻击。

示例代码：

func sanitize(userInput: String) -> String {
    // Remove any script tags or other potentially dangerous content
    return userInput.replacingOccurrences(of: "<script>", with: "", options: .caseInsensitive)
                    .replacingOccurrences(of: "</script>", with: "", options: .caseInsensitive)
}

// Usage
let userInput = "<script>alert('xss')</script>"
let sanitizedInput = sanitize(userInput: userInput)
print(sanitizedInput) // Outputs: alert('xss')

OC版

1. 使用HTTPS

确保所有的网络请求都使用HTTPS协议，以加密数据传输，防止中间人攻击。

示例代码：

在Info.plist中配置App Transport Security (ATS)：

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSAllowsArbitraryLoads</key>
    <false/>
</dict>

2. SSL Pinning

通过SSL Pinning可以确保应用程序只信任指定的服务器证书，防止被劫持到伪造的服务器。

示例代码：

#import <Foundation/Foundation.h>

@interface URLSessionPinningDelegate : NSObject <NSURLSessionDelegate>

@end

@implementation URLSessionPinningDelegate

- (void)URLSession:(NSURLSession *)session didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential * _Nullable credential))completionHandler {
    if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust]) {
        SecTrustRef serverTrust = challenge.protectionSpace.serverTrust;
        SecCertificateRef serverCertificate = SecTrustGetCertificateAtIndex(serverTrust, 0);
        
        NSString *certPath = [[NSBundle mainBundle] pathForResource:@"your_cert" ofType:@"cer"];
        NSData *localCertData = [NSData dataWithContentsOfFile:certPath];
        NSData *serverCertData = (__bridge NSData *)(SecCertificateCopyData(serverCertificate));
        
        if ([localCertData isEqualToData:serverCertData]) {
            NSURLCredential *credential = [NSURLCredential credentialForTrust:serverTrust];
            completionHandler(NSURLSessionAuthChallengeUseCredential, credential);
            return;
        }
    }
    completionHandler(NSURLSessionAuthChallengeCancelAuthenticationChallenge, nil);
}

@end

// Usage
NSURL *url = [NSURL URLWithString:@"https://yoursecurewebsite.com"];
NSURLSessionConfiguration *sessionConfig = [NSURLSessionConfiguration defaultSessionConfiguration];
URLSessionPinningDelegate *pinningDelegate = [[URLSessionPinningDelegate alloc] init];
NSURLSession *session = [NSURLSession sessionWithConfiguration:sessionConfig delegate:pinningDelegate delegateQueue:nil];

NSURLSessionDataTask *task = [session dataTaskWithURL:url completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
    if (error == nil) {
        // Handle response
    }
}];
[task resume];

3. 防止SQL注入

在处理用户输入时，使用参数化查询来防止SQL注入攻击。

示例代码：

#import <sqlite3.h>

- (void)queryDatabase:(NSString *)userInput {
    sqlite3 *db;
    // Open database (assuming dbPath is the path to your database)
    if (sqlite3_open([dbPath UTF8String], &db) == SQLITE_OK) {
        sqlite3_stmt *statement;
        const char *query = "SELECT * FROM users WHERE username = ?";
        
        if (sqlite3_prepare_v2(db, query, -1, &statement, NULL) == SQLITE_OK) {
            sqlite3_bind_text(statement, 1, [userInput UTF8String], -1, SQLITE_TRANSIENT);
            
            while (sqlite3_step(statement) == SQLITE_ROW) {
                // Process results
            }
        }
        
        sqlite3_finalize(statement);
        sqlite3_close(db);
    }
}

4. Data Encryption

在存储敏感数据时，使用iOS的加密库来加密数据，比如使用Keychain。

示例代码：

#import <Security/Security.h>

- (OSStatus)saveToKeychainWithKey:(NSString *)key data:(NSData *)data {
    NSDictionary *query = @{(__bridge id)kSecClass: (__bridge id)kSecClassGenericPassword,
                            (__bridge id)kSecAttrAccount: key,
                            (__bridge id)kSecValueData: data};
    
    SecItemDelete((__bridge CFDictionaryRef)query); // Delete any existing item
    return SecItemAdd((__bridge CFDictionaryRef)query, NULL); // Add new item
}

- (NSData *)loadFromKeychainWithKey:(NSString *)key {
    NSDictionary *query = @{(__bridge id)kSecClass: (__bridge id)kSecClassGenericPassword,
                            (__bridge id)kSecAttrAccount: key,
                            (__bridge id)kSecReturnData: (__bridge id)kCFBooleanTrue,
                            (__bridge id)kSecMatchLimit: (__bridge id)kSecMatchLimitOne};
    
    CFTypeRef dataTypeRef = NULL;
    OSStatus status = SecItemCopyMatching((__bridge CFDictionaryRef)query, &dataTypeRef);
    
    if (status == noErr) {
        return (__bridge_transfer NSData *)dataTypeRef;
    } else {
        return nil;
    }
}

5. 输入验证与清理

对用户输入进行验证和清理，防止XSS（跨站脚本攻击）和其他注入攻击。

示例代码：

- (NSString *)sanitize:(NSString *)userInput {
    // Remove any script tags or other potentially dangerous content
    NSString *sanitizedInput = [userInput stringByReplacingOccurrencesOfString:@"<script>" withString:@"" options:NSCaseInsensitiveSearch range:NSMakeRange(0, userInput.length)];
    sanitizedInput = [sanitizedInput stringByReplacingOccurrencesOfString:@"</script>" withString:@"" options:NSCaseInsensitiveSearch range:NSMakeRange(0, sanitizedInput.length)];
    return sanitizedInput;
}

// Usage
NSString *userInput = @"<script>alert('xss')</script>";
NSString *sanitizedInput = [self sanitize:userInput];
NSLog(@"%@", sanitizedInput); // Outputs: alert('xss')

通过这些措施，你可以显著提升iOS应用的网络安全性。根据项目需求，灵活运用这些技术以确保用户数据的安全。