mirror of
https://github.com/qtmleap/revkit.git
synced 2026-09-29 06:21:51 +02:00
tkgstrator
220e1d51a2
Enhances iOS MSL CBOR decoder for multi-item parsing, iOS-specific payload handling, and IV extraction from ciphertext. Updates NetflixCrypto to support Tweak-format key JSON. Extends the Tweak to capture DH key exchange material and session keys more reliably, saving full key histories and implementing better appboot phase tracking. Adds scripts for DH-derived HKDF parameter analysis and appboot key response investigation. Improves documentation on iOS CBOR MSL protocol differences, decryption pipeline, and key extraction workflow. Relates to iOS MSL traffic analysis and decryption research.
343 lines
14 KiB
Objective-C
343 lines
14 KiB
Objective-C
#import <Orion/Orion.h>
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#import <os/log.h>
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#import <substrate.h>
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#import <Foundation/Foundation.h>
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#import <objc/runtime.h>
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#import <dlfcn.h>
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static os_log_t g_log = NULL;
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static NSString *g_logFile = nil;
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static NSString *g_keyFile = nil;
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// Key storage — accumulated during session
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static NSMutableDictionary *g_keys = nil;
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static NSMutableArray *g_aesKeys = nil;
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static NSMutableArray *g_hmacKeys = nil;
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static BOOL g_appbootDone = NO;
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#define NFXKEY_LOG(fmt, ...) \
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do { \
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if (g_log) { os_log(g_log, fmt, ##__VA_ARGS__); } \
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NSLog(@"[NFXKey] " fmt, ##__VA_ARGS__); \
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} while (0)
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static void file_log(NSString *msg) {
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if (!g_logFile) return;
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@try {
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NSDateFormatter *df = [[NSDateFormatter alloc] init];
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df.dateFormat = @"HH:mm:ss.SSS";
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NSString *line = [NSString stringWithFormat:@"%@ %@\n", [df stringFromDate:[NSDate date]], msg];
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NSFileHandle *fh = [NSFileHandle fileHandleForWritingAtPath:g_logFile];
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if (!fh) {
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[line writeToFile:g_logFile atomically:YES encoding:NSUTF8StringEncoding error:nil];
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} else {
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[fh seekToEndOfFile];
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[fh writeData:[line dataUsingEncoding:NSUTF8StringEncoding]];
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[fh closeFile];
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}
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} @catch (NSException *e) {}
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}
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static NSString *hexEncode(const uint8_t *data, int len) {
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NSMutableString *s = [NSMutableString stringWithCapacity:len * 2];
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for (int i = 0; i < len; i++) {
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[s appendFormat:@"%02x", data[i]];
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}
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return s;
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}
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static void saveKeysToFile(void) {
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if (!g_keyFile || !g_keys) return;
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@try {
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NSData *json = [NSJSONSerialization dataWithJSONObject:g_keys
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options:NSJSONWritingPrettyPrinted
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error:nil];
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if (json) {
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[json writeToFile:g_keyFile atomically:YES];
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file_log([NSString stringWithFormat:@"[keys] saved to %@", g_keyFile]);
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}
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} @catch (NSException *e) {}
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}
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// ---------------------------------------------------------------------------
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// OpenSSL function pointers (resolved via dlsym)
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// ---------------------------------------------------------------------------
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typedef struct dh_st DH;
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typedef struct bignum_st BIGNUM;
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static void (*fn_DH_get0_key)(const DH *, const BIGNUM **, const BIGNUM **);
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static void (*fn_DH_get0_pqg)(const DH *, const BIGNUM **, const BIGNUM **, const BIGNUM **);
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static int (*fn_BN_num_bits)(const BIGNUM *);
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static int (*fn_BN_bn2bin)(const BIGNUM *, unsigned char *);
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// ---------------------------------------------------------------------------
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// Hook: DH_generate_key
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// ---------------------------------------------------------------------------
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static int (*orig_DH_generate_key)(DH *dh);
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static int hook_DH_generate_key(DH *dh) {
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int ret = orig_DH_generate_key(dh);
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if (ret == 1 && fn_DH_get0_key && fn_BN_num_bits && fn_BN_bn2bin) {
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const BIGNUM *pub = NULL, *priv = NULL;
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fn_DH_get0_key(dh, &pub, &priv);
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if (pub) {
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int pubBytes = (fn_BN_num_bits(pub) + 7) / 8;
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if (pubBytes > 0 && pubBytes <= 1024) {
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uint8_t *buf = (uint8_t *)malloc(pubBytes);
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fn_BN_bn2bin(pub, buf);
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NSString *hex = hexEncode(buf, pubBytes);
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file_log([NSString stringWithFormat:@"[DH_generate_key] pub_key (%d bytes)=%@",
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pubBytes, hex]);
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g_keys[@"dh_pub_key"] = hex;
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free(buf);
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}
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}
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if (priv) {
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int privBytes = (fn_BN_num_bits(priv) + 7) / 8;
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if (privBytes > 0 && privBytes <= 1024) {
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uint8_t *buf = (uint8_t *)malloc(privBytes);
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fn_BN_bn2bin(priv, buf);
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NSString *hex = hexEncode(buf, privBytes);
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file_log([NSString stringWithFormat:@"[DH_generate_key] priv_key (%d bytes)=%@",
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privBytes, hex]);
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g_keys[@"dh_priv_key"] = hex;
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free(buf);
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}
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}
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if (fn_DH_get0_pqg) {
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const BIGNUM *p = NULL, *q = NULL, *g = NULL;
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fn_DH_get0_pqg(dh, &p, &q, &g);
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if (p) {
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int pBytes = (fn_BN_num_bits(p) + 7) / 8;
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if (pBytes > 0 && pBytes <= 4096) {
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uint8_t *buf = (uint8_t *)malloc(pBytes);
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fn_BN_bn2bin(p, buf);
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NSString *hex = hexEncode(buf, pBytes);
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file_log([NSString stringWithFormat:@"[DH_generate_key] dh_p (%d bytes) head=%02x%02x%02x%02x",
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pBytes, buf[0], buf[1], buf[2], buf[3]]);
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g_keys[@"dh_p"] = hex;
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free(buf);
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}
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}
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if (g) {
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int gBytes = (fn_BN_num_bits(g) + 7) / 8;
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if (gBytes > 0 && gBytes <= 4096) {
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uint8_t *buf = (uint8_t *)malloc(gBytes);
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fn_BN_bn2bin(g, buf);
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NSString *hex = hexEncode(buf, gBytes);
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file_log([NSString stringWithFormat:@"[DH_generate_key] dh_g (%d bytes) head=%02x",
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gBytes, buf[0]]);
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g_keys[@"dh_g"] = hex;
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free(buf);
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}
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}
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}
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saveKeysToFile();
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}
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return ret;
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}
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// ---------------------------------------------------------------------------
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// Hook: DH_compute_key
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// ---------------------------------------------------------------------------
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static int (*orig_DH_compute_key)(unsigned char *key, const BIGNUM *pub_key, DH *dh);
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static int hook_DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) {
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int ret = orig_DH_compute_key(key, pub_key, dh);
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if (ret > 0) {
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NSString *hex = hexEncode(key, ret);
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file_log([NSString stringWithFormat:@"[DH_compute_key] shared_secret (%d bytes)=%@",
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ret, hex]);
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g_keys[@"dh_shared_secret"] = hex;
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saveKeysToFile();
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}
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return ret;
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}
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// ---------------------------------------------------------------------------
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// Hook: AES_set_encrypt_key / AES_set_decrypt_key
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// ---------------------------------------------------------------------------
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static int (*orig_AES_set_encrypt_key)(const unsigned char *userKey, int bits, void *key);
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static int hook_AES_set_encrypt_key(const unsigned char *userKey, int bits, void *key) {
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int keyLen = bits / 8;
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if (keyLen == 16 || keyLen == 32) {
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NSString *hex = hexEncode(userKey, keyLen);
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file_log([NSString stringWithFormat:@"[AES_set_encrypt_key] bits=%d key=%@", bits, hex]);
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// Track AES-128 keys for session key identification
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if (bits == 128) {
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NSString *phase = g_appbootDone ? @"post_appboot" : @"pre_appboot";
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NSDictionary *entry = @{@"key": hex, @"bits": @(bits), @"phase": phase};
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// Only add if not duplicate of last entry
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if (g_aesKeys.count == 0 || ![g_aesKeys.lastObject[@"key"] isEqualToString:hex]) {
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[g_aesKeys addObject:entry];
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}
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// Update current session enc_key
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g_keys[g_appbootDone ? @"session_enc_key" : @"pre_session_enc_key"] = hex;
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}
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}
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return orig_AES_set_encrypt_key(userKey, bits, key);
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}
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static int (*orig_AES_set_decrypt_key)(const unsigned char *userKey, int bits, void *key);
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static int hook_AES_set_decrypt_key(const unsigned char *userKey, int bits, void *key) {
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int keyLen = bits / 8;
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if (keyLen == 16 || keyLen == 32) {
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file_log([NSString stringWithFormat:@"[AES_set_decrypt_key] bits=%d key=%@",
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bits, hexEncode(userKey, keyLen)]);
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}
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return orig_AES_set_decrypt_key(userKey, bits, key);
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}
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// ---------------------------------------------------------------------------
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// Hook: HMAC
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// ---------------------------------------------------------------------------
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static unsigned char *(*orig_HMAC)(const void *evp_md, const void *key, int key_len,
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const unsigned char *d, size_t n, unsigned char *md, unsigned int *md_len);
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static unsigned char *hook_HMAC(const void *evp_md, const void *key, int key_len,
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const unsigned char *d, size_t n, unsigned char *md, unsigned int *md_len) {
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if (key_len == 32) {
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NSString *hex = hexEncode((const uint8_t *)key, key_len);
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file_log([NSString stringWithFormat:@"[HMAC] key_len=%d key=%@", key_len, hex]);
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NSString *phase = g_appbootDone ? @"post_appboot" : @"pre_appboot";
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NSDictionary *entry = @{@"key": hex, @"phase": phase};
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if (g_hmacKeys.count == 0 || ![g_hmacKeys.lastObject[@"key"] isEqualToString:hex]) {
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[g_hmacKeys addObject:entry];
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}
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// Update current session hmac_key
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g_keys[g_appbootDone ? @"session_hmac_key" : @"pre_session_hmac_key"] = hex;
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}
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return orig_HMAC(evp_md, key, key_len, d, n, md, md_len);
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}
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// ---------------------------------------------------------------------------
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// Hook: IosMslClient.setDidAppboot:
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// ---------------------------------------------------------------------------
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static void (*orig_setDidAppboot)(id self, SEL _cmd, BOOL value);
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static void hook_setDidAppboot(id self, SEL _cmd, BOOL value) {
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file_log([NSString stringWithFormat:@"setDidAppboot: %d", value]);
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NFXKEY_LOG("setDidAppboot: %d", value);
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if (value) {
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g_appbootDone = YES;
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// Snapshot pre-appboot keys
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g_keys[@"aes_key_history"] = [g_aesKeys copy];
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g_keys[@"hmac_key_history"] = [g_hmacKeys copy];
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}
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orig_setDidAppboot(self, _cmd, value);
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if (value) {
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// Save after original method (which may trigger key exchange)
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dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3 * NSEC_PER_SEC)),
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dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
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// Final save with post-appboot keys
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g_keys[@"aes_key_history"] = [g_aesKeys copy];
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g_keys[@"hmac_key_history"] = [g_hmacKeys copy];
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NSDateFormatter *df = [[NSDateFormatter alloc] init];
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df.dateFormat = @"yyyy-MM-dd'T'HH:mm:ss";
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g_keys[@"timestamp"] = [df stringFromDate:[NSDate date]];
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saveKeysToFile();
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file_log(@"[keys] final save after appboot");
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});
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}
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}
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// ---------------------------------------------------------------------------
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// Constructor
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// ---------------------------------------------------------------------------
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__attribute__((constructor)) static void init(void) {
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orion_init();
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g_log = os_log_create("dev.tkgstrator.charon", "keyextract");
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g_logFile = [NSTemporaryDirectory() stringByAppendingPathComponent:@"nfxkey.log"];
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g_keyFile = [NSTemporaryDirectory() stringByAppendingPathComponent:@"msl_keys.json"];
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g_keys = [NSMutableDictionary dictionary];
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g_aesKeys = [NSMutableArray array];
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g_hmacKeys = [NSMutableArray array];
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g_appbootDone = NO;
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file_log(@"=== AppbootKeyExtract loaded ===");
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NFXKEY_LOG("AppbootKeyExtract loaded");
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// Hook IosMslClient.setDidAppboot:
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Class cls = objc_getClass("IosMslClient");
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if (cls) {
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MSHookMessageEx(cls, @selector(setDidAppboot:),
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(IMP)hook_setDidAppboot, (IMP *)&orig_setDidAppboot);
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file_log(@"[+] setDidAppboot: hooked");
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NFXKEY_LOG(" [+] setDidAppboot: hooked");
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}
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// Hook NFWebCrypto functions
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void *nfwc = dlopen("@rpath/NFWebCrypto.framework/NFWebCrypto", RTLD_NOLOAD);
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if (!nfwc) {
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nfwc = dlopen("/usr/lib/libNFWebCrypto.dylib", RTLD_NOLOAD);
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}
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if (nfwc) {
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// Resolve helper functions
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fn_DH_get0_key = (void (*)(const DH *, const BIGNUM **, const BIGNUM **))dlsym(nfwc, "DH_get0_key");
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fn_DH_get0_pqg = (void (*)(const DH *, const BIGNUM **, const BIGNUM **, const BIGNUM **))dlsym(nfwc, "DH_get0_pqg");
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fn_BN_num_bits = (int (*)(const BIGNUM *))dlsym(nfwc, "BN_num_bits");
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fn_BN_bn2bin = (int (*)(const BIGNUM *, unsigned char *))dlsym(nfwc, "BN_bn2bin");
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// DH hooks
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void *dhGenKey = dlsym(nfwc, "DH_generate_key");
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void *dhCompKey = dlsym(nfwc, "DH_compute_key");
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if (dhGenKey) {
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MSHookFunction(dhGenKey, (void *)hook_DH_generate_key, (void **)&orig_DH_generate_key);
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file_log(@"[+] DH_generate_key hooked");
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NFXKEY_LOG(" [+] DH_generate_key hooked");
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}
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if (dhCompKey) {
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MSHookFunction(dhCompKey, (void *)hook_DH_compute_key, (void **)&orig_DH_compute_key);
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file_log(@"[+] DH_compute_key hooked");
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NFXKEY_LOG(" [+] DH_compute_key hooked");
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}
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// AES hooks
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void *aesEncKey = dlsym(nfwc, "AES_set_encrypt_key");
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void *aesDecKey = dlsym(nfwc, "AES_set_decrypt_key");
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void *hmacFn = dlsym(nfwc, "HMAC");
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if (aesEncKey) {
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MSHookFunction(aesEncKey, (void *)hook_AES_set_encrypt_key, (void **)&orig_AES_set_encrypt_key);
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file_log(@"[+] AES_set_encrypt_key hooked");
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NFXKEY_LOG(" [+] AES_set_encrypt_key hooked");
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}
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if (aesDecKey) {
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MSHookFunction(aesDecKey, (void *)hook_AES_set_decrypt_key, (void **)&orig_AES_set_decrypt_key);
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file_log(@"[+] AES_set_decrypt_key hooked");
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NFXKEY_LOG(" [+] AES_set_decrypt_key hooked");
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}
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if (hmacFn) {
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MSHookFunction(hmacFn, (void *)hook_HMAC, (void **)&orig_HMAC);
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file_log(@"[+] HMAC hooked");
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NFXKEY_LOG(" [+] HMAC hooked");
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}
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} else {
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file_log(@"[-] NFWebCrypto not loaded");
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NFXKEY_LOG(" [-] NFWebCrypto not loaded");
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}
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NFXKEY_LOG("AppbootKeyExtract: done");
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}
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