Use SHA256 signature instead of SHA1 for iOS 4 and newer when creating and signing pairing certificates

4 files changed, 18 insertions, 17 deletions

diff --git a/common/userpref.c b/common/userpref.c
index 08ab7e2..76945e1 100644
--- a/common/userpref.c
+++ b/common/userpref.c
@@ -77,6 +77,7 @@
 #define ETIMEDOUT 138
 #endif
 
+#include <libimobiledevice/libimobiledevice.h>
 #include <libimobiledevice-glue/utils.h>
 
 #include "userpref.h"
@@ -419,7 +420,7 @@ static int _mbedtls_x509write_crt_set_basic_constraints_critical(mbedtls_x509wri
  *
  * @return 1 if keys were successfully generated, 0 otherwise
  */
-userpref_error_t pair_record_generate_keys_and_certs(plist_t pair_record, key_data_t public_key)
+userpref_error_t pair_record_generate_keys_and_certs(plist_t pair_record, key_data_t public_key, unsigned int device_version)
 {
         userpref_error_t ret = USERPREF_E_SSL_ERROR;
 
@@ -484,7 +485,7 @@ userpref_error_t pair_record_generate_keys_and_certs(plist_t pair_record, key_da
                 X509_set_pubkey(root_cert, root_pkey);
 
                 /* sign root cert with root private key */
-                X509_sign(root_cert, root_pkey, EVP_sha1());
+                X509_sign(root_cert, root_pkey, (device_version < IDEVICE_DEVICE_VERSION(4,0,0)) ? EVP_sha1() : EVP_sha256());
         }
 
         /* create host certificate */
@@ -517,7 +518,7 @@ userpref_error_t pair_record_generate_keys_and_certs(plist_t pair_record, key_da
                 X509_set_pubkey(host_cert, host_pkey);
 
                 /* sign host cert with root private key */
-                X509_sign(host_cert, root_pkey, EVP_sha1());
+                X509_sign(host_cert, root_pkey, (device_version < IDEVICE_DEVICE_VERSION(4,0,0)) ? EVP_sha1() : EVP_sha256());
         }
 
         if (root_cert && root_pkey && host_cert && host_pkey) {
@@ -609,7 +610,7 @@ userpref_error_t pair_record_generate_keys_and_certs(plist_t pair_record, key_da
                 X509_add_ext_helper(dev_cert, NID_key_usage, (char*)"critical,digitalSignature,keyEncipherment");
 
                 /* sign device certificate with root private key */
-                if (X509_sign(dev_cert, root_pkey, EVP_sha1())) {
+                if (X509_sign(dev_cert, root_pkey, (device_version < IDEVICE_DEVICE_VERSION(4,0,0)) ? EVP_sha1() : EVP_sha256())) {
                         /* if signing succeeded, export in PEM format */
                         BIO* membp = BIO_new(BIO_s_mem());
                         if (PEM_write_bio_X509(membp, dev_cert) > 0) {
@@ -661,7 +662,7 @@ userpref_error_t pair_record_generate_keys_and_certs(plist_t pair_record, key_da
         gnutls_x509_crt_set_ca_status(root_cert, 1);
         gnutls_x509_crt_set_activation_time(root_cert, time(NULL));
         gnutls_x509_crt_set_expiration_time(root_cert, time(NULL) + (60 * 60 * 24 * 365 * 10));
-        gnutls_x509_crt_sign2(root_cert, root_cert, root_privkey, GNUTLS_DIG_SHA1, 0);
+        gnutls_x509_crt_sign2(root_cert, root_cert, root_privkey, (device_version < IDEVICE_DEVICE_VERSION(4,0,0)) ? GNUTLS_DIG_SHA1 : GNUTLS_DIG_SHA256, 0);
 
         gnutls_x509_crt_set_key(host_cert, host_privkey);
         gnutls_x509_crt_set_serial(host_cert, "\x01", 1);
@@ -670,7 +671,7 @@ userpref_error_t pair_record_generate_keys_and_certs(plist_t pair_record, key_da
         gnutls_x509_crt_set_key_usage(host_cert, GNUTLS_KEY_KEY_ENCIPHERMENT | GNUTLS_KEY_DIGITAL_SIGNATURE);
         gnutls_x509_crt_set_activation_time(host_cert, time(NULL));
         gnutls_x509_crt_set_expiration_time(host_cert, time(NULL) + (60 * 60 * 24 * 365 * 10));
-        gnutls_x509_crt_sign2(host_cert, root_cert, root_privkey, GNUTLS_DIG_SHA1, 0);
+        gnutls_x509_crt_sign2(host_cert, root_cert, root_privkey, (device_version < IDEVICE_DEVICE_VERSION(4,0,0)) ? GNUTLS_DIG_SHA1 : GNUTLS_DIG_SHA256, 0);
 
         /* export to PEM format */
         size_t root_key_export_size = 0;
@@ -768,17 +769,17 @@ userpref_error_t pair_record_generate_keys_and_certs(plist_t pair_record, key_da
                         gnutls_x509_crt_set_expiration_time(dev_cert, time(NULL) + (60 * 60 * 24 * 365 * 10));
 
                         /* use custom hash generation for compatibility with the "Apple ecosystem" */
-                        const gnutls_digest_algorithm_t dig_sha1 = GNUTLS_DIG_SHA1;
-                        size_t hash_size = gnutls_hash_get_len(dig_sha1);
+                        const gnutls_digest_algorithm_t dig_sha = (device_version < IDEVICE_DEVICE_VERSION(4,0,0)) ? GNUTLS_DIG_SHA1 : GNUTLS_DIG_SHA256;
+                        size_t hash_size = gnutls_hash_get_len(dig_sha);
                         unsigned char hash[hash_size];
-                        if (gnutls_hash_fast(dig_sha1, der_pub_key.data, der_pub_key.size, (unsigned char*)&hash) < 0) {
-                                debug_info("ERROR: Failed to generate SHA1 for public key");
+                        if (gnutls_hash_fast(dig_sha, der_pub_key.data, der_pub_key.size, (unsigned char*)&hash) < 0) {
+                                debug_info("ERROR: Failed to generate SHA for public key");
                         } else {
                                 gnutls_x509_crt_set_subject_key_id(dev_cert, hash, hash_size);
                         }
 
                         gnutls_x509_crt_set_key_usage(dev_cert, GNUTLS_KEY_DIGITAL_SIGNATURE | GNUTLS_KEY_KEY_ENCIPHERMENT);
-                        gnutls_error = gnutls_x509_crt_sign2(dev_cert, root_cert, root_privkey, GNUTLS_DIG_SHA1, 0);
+                        gnutls_error = gnutls_x509_crt_sign2(dev_cert, root_cert, root_privkey, (device_version < IDEVICE_DEVICE_VERSION(4,0,0)) ? GNUTLS_DIG_SHA1 : GNUTLS_DIG_SHA256, 0);
                         if (GNUTLS_E_SUCCESS == gnutls_error) {
                                 /* if everything went well, export in PEM format */
                                 size_t export_size = 0;
@@ -872,7 +873,7 @@ userpref_error_t pair_record_generate_keys_and_certs(plist_t pair_record, key_da
 
         /* sign root cert with root private key */
         mbedtls_x509write_crt_set_issuer_key(&cert, &root_pkey);
-        mbedtls_x509write_crt_set_md_alg(&cert, MBEDTLS_MD_SHA1);
+        mbedtls_x509write_crt_set_md_alg(&cert, (device_version < IDEVICE_DEVICE_VERSION(4,0,0)) ? MBEDTLS_MD_SHA1 : MBEDTLS_MD_SHA256);
 
         unsigned char outbuf[16384];
 
@@ -931,7 +932,7 @@ userpref_error_t pair_record_generate_keys_and_certs(plist_t pair_record, key_da
 
         /* sign host cert with root private key */
         mbedtls_x509write_crt_set_issuer_key(&cert, &root_pkey);
-        mbedtls_x509write_crt_set_md_alg(&cert, MBEDTLS_MD_SHA1);
+        mbedtls_x509write_crt_set_md_alg(&cert, (device_version < IDEVICE_DEVICE_VERSION(4,0,0)) ? MBEDTLS_MD_SHA1 : MBEDTLS_MD_SHA256);
 
         /* write host private key */
         mbedtls_pk_write_key_pem(&host_pkey, outbuf, sizeof(outbuf));
@@ -991,7 +992,7 @@ userpref_error_t pair_record_generate_keys_and_certs(plist_t pair_record, key_da
 
         /* sign device certificate with root private key */
         mbedtls_x509write_crt_set_issuer_key(&cert, &root_pkey);
-        mbedtls_x509write_crt_set_md_alg(&cert, MBEDTLS_MD_SHA1);
+        mbedtls_x509write_crt_set_md_alg(&cert, (device_version < IDEVICE_DEVICE_VERSION(4,0,0)) ? MBEDTLS_MD_SHA1 : MBEDTLS_MD_SHA256);
 
         /* write device certificate */
         mbedtls_x509write_crt_pem(&cert, outbuf, sizeof(outbuf), mbedtls_ctr_drbg_random, &ctr_drbg);
diff --git a/common/userpref.h b/common/userpref.h
index 75bb8b7..9a1832c 100644
--- a/common/userpref.h
+++ b/common/userpref.h
@@ -68,7 +68,7 @@ userpref_error_t userpref_read_pair_record(const char *udid, plist_t *pair_recor
 userpref_error_t userpref_save_pair_record(const char *udid, uint32_t device_id, plist_t pair_record);
 userpref_error_t userpref_delete_pair_record(const char *udid);
 
-userpref_error_t pair_record_generate_keys_and_certs(plist_t pair_record, key_data_t public_key);
+userpref_error_t pair_record_generate_keys_and_certs(plist_t pair_record, key_data_t public_key, unsigned int device_version);
 #if  defined(HAVE_OPENSSL) || defined(HAVE_MBEDTLS)
 userpref_error_t pair_record_import_key_with_name(plist_t pair_record, const char* name, key_data_t* key);
 userpref_error_t pair_record_import_crt_with_name(plist_t pair_record, const char* name, key_data_t* cert);
diff --git a/src/lockdown-cu.c b/src/lockdown-cu.c
index 30eec99..11c70c5 100644
--- a/src/lockdown-cu.c
+++ b/src/lockdown-cu.c
@@ -1132,7 +1132,7 @@ lockdownd_error_t lockdownd_pair_cu(lockdownd_client_t client)
         plist_free(pubkey);     
 
         plist_t pair_record_plist = plist_new_dict();
-        pair_record_generate_keys_and_certs(pair_record_plist, public_key);
+        pair_record_generate_keys_and_certs(pair_record_plist, public_key, client->device->version);
 
         char* host_id = NULL;
         char* system_buid = NULL;
diff --git a/src/lockdown.c b/src/lockdown.c
index d28316a..1edb99b 100644
--- a/src/lockdown.c
+++ b/src/lockdown.c
@@ -839,7 +839,7 @@ static lockdownd_error_t pair_record_generate(lockdownd_client_t client, plist_t
 
         /* generate keys and certificates into pair record */
         userpref_error_t uret = USERPREF_E_SUCCESS;
-        uret = pair_record_generate_keys_and_certs(*pair_record, public_key);
+        uret = pair_record_generate_keys_and_certs(*pair_record, public_key, client->device->version);
         switch(uret) {
                 case USERPREF_E_INVALID_ARG:
                         ret = LOCKDOWN_E_INVALID_ARG;