Example SMC implementation (load_aes_key)

exosphere/smc_api.c

@@ -2,6 +2,7 @@
 
 #include "utils.h"
 #include "smc_api.h"
+#include "smc_user.h"
 #include "se.h"
 
 #define SMC_USER_HANDLERS 0x13
@@ -93,10 +94,10 @@ smc_table_t g_smc_tables[2] = {
 };
 
 int g_is_smc_in_progress = 0;
-uint32_t (*g_smc_callback)(uint64_t, uint64_t) = NULL;
+uint32_t (*g_smc_callback)(void *, uint64_t) = NULL;
 uint64_t g_smc_callback_key = 0;
 
-uint64_t try_set_smc_callback(uint32_t (*callback)(uint64_t, uint64_t)) {
+uint64_t try_set_smc_callback(uint32_t (*callback)(void *, uint64_t)) {
     uint64_t key;
     /* TODO: Atomics... */
     if (g_smc_callback_key) {
@@ -158,7 +159,7 @@ uint32_t smc_wrapper_sync(smc_args_t *args, uint32_t (*handler)(smc_args_t *)) {
     return result;
 }
 
-uint32_t smc_wrapper_async(smc_args_t *args, uint32_t (*handler)(smc_args_t *), uint32_t (*callback)(uint64_t, uint64_t)) {
+uint32_t smc_wrapper_async(smc_args_t *args, uint32_t (*handler)(smc_args_t *), uint32_t (*callback)(void *, uint64_t)) {
     uint32_t result;
     uint64_t key;
     /* TODO: Make g_is_smc_in_progress atomic. */
@@ -182,3 +183,45 @@ uint32_t smc_wrapper_async(smc_args_t *args, uint32_t (*handler)(smc_args_t *),
     g_is_smc_in_progress = 0;
     return result;
 }
+
+uint32_t smc_check_status(smc_args_t *args) {
+    if (g_smc_callback_key == 0) {
+        return 4;
+    }
+    
+    if (args->X[1] != g_smc_callback_key) {
+        return 5;
+    }
+    
+    args->X[1] = g_smc_callback(NULL, 0);
+    
+    g_smc_callback_key = 0;
+    return 0;
+}
+
+uint32_t smc_get_result(smc_args_t *) {
+    uint32_t status;
+    unsigned char result_buf[0x400];
+    if (g_smc_callback_key == 0) {
+        return 4;
+    }
+    
+    if (args->X[1] != g_smc_callback_key) {
+        return 5;
+    }
+    
+    /* Check result size */
+    if (args->X[3] > 0x400) {
+        return 2;
+    }
+    
+    args->X[1] = g_smc_callback(result_buf, args->X[3]);
+    g_smc_callback_key = 0;
+    
+    /* TODO: Copy result from result_buf into output in args->X[2] */
+    return 0;
+}
+
+uint32_t smc_load_aes_key(smc_args_t *args) {
+    smc_wrapper_sync(args, user_load_aes_key);
+}

exosphere/smc_user.c

@@ -0,0 +1,31 @@
+#include <stdint.h>
+
+#include "utils.h"
+#include "smc_api.h"
+#include "smc_user.h"
+#include "se.h"
+
+uint32_t user_load_aes_key(smc_args_t *args) {
+    unsigned char sealed_kek[0x10];
+    unsigned char wrapped_key[0x10];
+    uint64_t *p_sealed_kek = (uint64_t *)(&sealed_kek[0]);
+    uint64_t *p_wrapped_key = (uint64_t *)(&wrapped_key[0]);
+    
+    uint32_t keyslot = (uint32_t)args->X[1];
+    if (keyslot > 3) {
+        return 2;
+    }
+    
+    /* Copy keydata */
+    p_sealed_kek[0] = args->X[2];
+    p_sealed_kek[1] = args->X[3];
+    p_wrapped_key[0] = args->X[4];
+    p_wrapped_key[1] = args->X[5];
+    
+    /* TODO: Unseal the kek. */
+    set_aes_keyslot(9, sealed_kek, 0x10);
+    
+    /* Unwrap the key. */
+    decrypt_data_into_keyslot(keyslot, 9, wrapped_key, 0x10);
+    return 0;
+}

exosphere/smc_user.h

@@ -0,0 +1,21 @@
+#ifndef EXOSPHERE_SMC_USER_H
+#define EXOSPHERE_SMC_USER_H
+
+#include "smc_api.h"
+
+uint32_t user_exp_mod(smc_args_t *args);
+uint32_t user_get_random_bytes(smc_args_t *args);
+uint32_t user_generate_aes_kek(smc_args_t *args);
+uint32_t user_load_aes_key(smc_args_t *args);
+uint32_t user_crypt_aes(smc_args_t *args);
+uint32_t user_generate_specific_aes_key(smc_args_t *args);
+uint32_t user_compute_cmac(smc_args_t *args);
+uint32_t user_load_rsa_private_key(smc_args_t *args);
+uint32_t user_decrypt_rsa_private_key(smc_args_t *args);
+uint32_t user_load_rsa_oaep_key(smc_args_t *args);
+uint32_t user_rsa_oaep(smc_args_t *args);
+uint32_t user_unwrap_rsa_wrapped_titlekey(smc_args_t *args);
+uint32_t user_load_titlekey(smc_args_t *args);
+uint32_t user_unwrap_aes_wrapped_titlekey(smc_args_t *args);
+
+#endif