DecryptPKG.m

#include <dlfcn.h>
//#include <mach-o/dyld.h>
//#include <mach-o/getsect.h>
//#include <mach-o/ldsyms.h>
#include <stdio.h>
#include <string.h>
#include <sys/clonefile.h>
#include <sys/errno.h>
#include <sys/syslimits.h>

#import <AppKit/AppKit.h>
#import <Foundation/Foundation.h>

#import "DecryptOperation.h"
#import "PKArchive.h"

// % /usr/libexec/PlistBuddy -c 'Print :Program' /System/Library/LaunchAgents/com.apple.storedownloadd.plist
// /System/Library/PrivateFrameworks/CommerceKit.framework/Versions/A/Resources/storedownloadd
//#define DO_OBJ "/System/Library/PrivateFrameworks/CommerceKit.framework/Resources/storedownloadd"

// % nm -U /System/Library/PrivateFrameworks/CommerceKit.framework/Versions/A/Resources/storedownloadd
// 0000000100000000 T __mh_execute_header
//#define DO_SYM MH_EXECUTE_SYM

// % nm -arch x86_64 -U ./storedownloadd | awk '$2 == "T" && $3 == "__mh_execute_header" { print $1 }'
// 0000000100000000
//#define DO_BAS ((uintptr_t) &_mh_execute_header)

// % dyld_info -arch x86_64 -objc ./storedownloadd | awk '$1 == "class" && $4 == "DecryptOperation" { print $2 }'
// 0x1001157C8
//#define DO_OFF 0x00000001001157C8

int main(int argc, const char *argv[]) {
    if (argc < 2) {
        fprintf(stderr, "Usage: %s <pkg-path>\n", argv[0]);
        return EXIT_FAILURE;
    }
    const char *pkg_path = argv[1];

    // TODO(t0rr3sp3dr0): allow inline base64-encoded dpInfo
    // TODO(t0rr3sp3dr0): allow pkg from stdin
    // TODO(t0rr3sp3dr0): allow pkg to stdout
    
//    uintptr_t do_off = (uintptr_t) NULL;
//
//    @autoreleasepool {
//        NSError *error = nil;
//
//        NSPipe *pipe = [NSPipe pipe];
//
//        NSTask *task = [[NSTask alloc] init];
//        [task setLaunchPath:@"/bin/sh"];
//        [task setArguments:@[
//            @"-c",
//            @"dyld_info -arch \"$(uname -m)\" -objc '" @DO_OBJ @"' | awk '$1 == \"class\" && $4 == \"DecryptOperation\" { print $2 }'",
//        ]];
//        [task setStandardOutput:pipe];
//        [task launchAndReturnError:&error];
//        if (error) {
//            NSLog(@"launchAndReturnError: %@", error);
//            return EXIT_FAILURE;
//        }
//
//        NSData *data = [[pipe fileHandleForReading] readDataToEndOfFileAndReturnError:&error];
//        if (error) {
//            NSLog(@"readDataToEndOfFileAndReturnError: %@", error);
//            return EXIT_FAILURE;
//        }
//
//        NSString *output = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
//
//        unsigned long long ull = 0;
//
//        NSScanner *scanner = [NSScanner scannerWithString:output];
//        BOOL ret = [scanner scanHexLongLong:&ull];
//        if (!ret) {
//            NSLog(@"scanner: %hhd", ret);
//            return EXIT_FAILURE;
//        }
//
//        if (ull == +HUGE_VAL) {
//            NSLog(@"scanner: +HUGE_VAL");
//            return EXIT_FAILURE;
//        }
//        if (ull == -HUGE_VAL) {
//            NSLog(@"scanner: -HUGE_VAL");
//            return EXIT_FAILURE;
//        }
//
//        do_off = ull;
//    }
    
    @autoreleasepool {
        NSArray <NSString *> *args = [[NSProcessInfo processInfo] arguments];
        NSString *pkgPath = args[1];

        PKArchive *archive = [PKArchive archiveWithPath:pkgPath];
        NSError *error = nil;
        BOOL ok = [archive verifyReturningError:&error];
        if (error) {
            NSLog(@"%@", error);
            return EXIT_FAILURE;
        }
        if (ok) {
            NSLog(@"NOOP");
            return EXIT_SUCCESS;
        }
    }
    
    char dec_path[PATH_MAX] = { '\0' };
    strcat(dec_path, pkg_path);
    strcat(dec_path, ":tmp");
    // TODO(t0rr3sp3dr0): check bounds before appending
    
    // TODO(t0rr3sp3dr0): handle EEXIST
    int ret0 = clonefile(pkg_path, dec_path, 0);
    if (ret0) {
        fprintf(stderr, "%s\n", strerror(errno));
        return EXIT_FAILURE;
    }
    // TODO(t0rr3sp3dr0): clean up on failure

    void *handle = dlopen("/System/Library/PrivateFrameworks/CommerceKit.framework/Versions/A/Resources/storedownloadd", RTLD_LAZY);
    if (!handle) {
        fprintf(stderr, "%s\n", dlerror());
        return EXIT_FAILURE;
    }

//    void *symbol = dlsym(handle, DO_SYM);
//    if (!symbol) {
//        fprintf(stderr, "%s\n", dlerror());
//        return EXIT_FAILURE;
//    }
//
//    unsigned long size = 0;
//    void *data = getsectiondata(symbol, "__DATA_CONST", "__objc_classrefs__DATA_CONST", &size);

    @autoreleasepool {
//        Class _DecryptOperation = nil;
//        for (size_t i = 0; i < size / sizeof(Class *); ++i) {
//            Class class = (__bridge Class)(data + i * sizeof(Class *));
//
//            NSString *name = NSStringFromClass(class);
//            if ([name isEqual: @"DecryptOperation"]) {
//                _DecryptOperation = class;
//                break;
//            }
//        }

//        NSArray <NSString *> *args = [[NSProcessInfo processInfo] arguments];
//        NSString *pkgPath = args[1];
        NSString *pkgPath = [NSString stringWithCString:dec_path encoding:NSUTF8StringEncoding];

        NSError *err0 = nil;
        NSData *dpInfo = [[NSFileHandle fileHandleWithStandardInput] readDataToEndOfFileAndReturnError:&err0];
        if (err0) {
            NSLog(@"%@", err0);
            return EXIT_FAILURE;
        }
        // TODO(t0rr3sp3dr0): check lenght of dpInfo
        
        DecryptOperation *decryptOperation = [[NSClassFromString(@"DecryptOperation") alloc] initWithLocalFilePath:pkgPath dpInfo:dpInfo storeClient:nil];
        [decryptOperation run];
        
        PKArchive *archive = [PKArchive archiveWithPath:pkgPath];
        NSError *err1 = nil;
        BOOL ok = [archive verifyReturningError:&err1];
        if (err1) {
            NSLog(@"%@", err1);
            return EXIT_FAILURE;
        }
        if (!ok) {
            NSLog(@"FAIL");
            return EXIT_FAILURE;
        }
    }

    int ret1 = dlclose(handle);
    if (ret1) {
        fprintf(stderr, "%s\n", dlerror());
        return EXIT_FAILURE;
    }
    
    int ret2 = rename(dec_path, pkg_path);
    if (ret2) {
        fprintf(stderr, "%s\n", strerror(errno));
        return EXIT_FAILURE;
    }
    
    fprintf(stderr, "SUCC\n");
    return EXIT_SUCCESS;
}