IOS Jailbreak How do intercept SMS / Text Messages

Question

I'm currently trying to write an application that intercepts text messages and reacts depending on the content of that message. I tried to hook into _receivedMessage:(struct __CKSMSRecord *)message replace:(BOOL)replace method in the CKSMSService class but this seems not do get called at all.

Could someone please tell me what function/class i have to hook in? I need to intercept the text message before it gets displayed and stored into the database. I'm on IOS 5.0.1.

Any help is truly appreciated.

Answer 1

This code snippet should intercept SMS messages- You can extend it for other kinds of notifications. Will work on iOS 5.0.1 as well. Does not work with iMessages though. Link with CoreTelephony framework (there are bunch of private headers there which you'd can class-dump)

#include <dlfcn.h>

#define CORETELPATH "/System/Library/PrivateFrameworks/CoreTelephony.framework/CoreTelephony"
id(*CTTelephonyCenterGetDefault)();

void (*CTTelephonyCenterAddObserver) (id,id,CFNotificationCallback,NSString*,void*,int);


static void telephonyEventCallback(CFNotificationCenterRef center, void *observer, CFStringRef name, const void *object, CFDictionaryRef userInfo)
{
    NSString *notifyname=(NSString *)name;
    if ([notifyname isEqualToString:@"kCTMessageReceivedNotification"])//received SMS
    {
        NSLog(@" SMS Notification Received :kCTMessageReceivedNotification");
        // Do blocking here. 
    }
}

-(void) registerCallback {

 void *handle = dlopen(CORETELPATH, RTLD_LAZY);
    CTTelephonyCenterGetDefault = dlsym(handle, "CTTelephonyCenterGetDefault");
    CTTelephonyCenterAddObserver = dlsym(handle,"CTTelephonyCenterAddObserver");
    dlclose(handle);
    id ct = CTTelephonyCenterGetDefault();

    CTTelephonyCenterAddObserver(
                                 ct, 
                                 NULL, 
                                 telephonyEventCallback,
                                 NULL,
                                 NULL,
                                 CFNotificationSuspensionBehaviorDeliverImmediately);
}

Answer 2

Although the poster already accepted rajagp's answer, I'm pretty sure it doesn't do what the question actually asked, on iOS 5. For iOS 5, I'm no longer seeing the message content anymore, although I do get notified that there is a new message.

So, what I did is take rajagp's notification handler for kCTMessageReceivedNotification, and inside it, use the code posted here to actually get the content of the text message, from the SMS database.