Implement masterkey logic, KEYSLOT defines.

exosphere/masterkey.c

@@ -0,0 +1,90 @@
+#include <stdint.h>
+
+#include "utils.h"
+#include "masterkey.h"
+#include "se.h"
+
+unsigned int g_mkey_revision = 0;
+int g_determined_mkey_revision = 0;
+
+uint8_t g_old_masterkeys[MASTERKEY_REVISION_MAX][0x10];
+
+/* TODO: Dev keys. */
+
+/* TODO: Extend with new vectors, as needed. */
+const uint8_t mkey_vectors[MASTERKEY_REVISION_MAX][0x10] = 
+{
+    {0x0C, 0xF0, 0x59, 0xAC, 0x85, 0xF6, 0x26, 0x65, 0xE1, 0xE9, 0x19, 0x55, 0xE6, 0xF2, 0x67, 0x3D}, /* Zeroes encrypted with Master Key 00. */
+    {0x29, 0x4C, 0x04, 0xC8, 0xEB, 0x10, 0xED, 0x9D, 0x51, 0x64, 0x97, 0xFB, 0xF3, 0x4D, 0x50, 0xDD}, /* Master key 00 encrypted with Master key 01. */
+    {0xDE, 0xCF, 0xEB, 0xEB, 0x10, 0xAE, 0x74, 0xD8, 0xAD, 0x7C, 0xF4, 0x9E, 0x62, 0xE0, 0xE8, 0x72}, /* Master key 01 encrypted with Master key 02. */
+    {0x0A, 0x0D, 0xDF, 0x34, 0x22, 0x06, 0x6C, 0xA4, 0xE6, 0xB1, 0xEC, 0x71, 0x85, 0xCA, 0x4E, 0x07}, /* Master key 02 encrypted with Master key 03. */
+}
+
+int check_mkey_revision(unsigned int revision) {
+    uint8_t final_vector[0x10];
+    
+    unsigned int check_keyslot = KEYSLOT_SWITCH_MASTERKEY;
+    if (revision > 0) {
+        /* Generate old master key array. */
+        for (unsigned int i = revision; i > 0; i--) {
+            se_aes_ecb_decrypt_block(check_keyslot, g_old_masterkeys[i-1], 0x10, mkey_vectors[i], 0x10);
+            set_aes_keyslot(KEYSLOT_SWITCH_TEMPKEY, g_old_masterkeys[i-1], 0x10);
+            check_keyslot = KEYSLOT_SWITCH_TEMPKEY;
+        }
+    }
+    
+    se_aes_ecb_decrypt_block(check_keyslot, final_vector, 0x10, mkey_vectors[0], 0x10);
+    for (unsigned int i = 0; i < 0x10; i++) {
+        if (final_vector[i] != 0) {
+            return 0;
+        }
+    }
+    return 1;
+}
+
+void mkey_detect_revision(void) {
+    if (g_determined_mkey_revision == 1) {
+        panic();
+    }
+    
+    for (unsigned int rev = 0; rev < MASTERKEY_REVISION_MAX; rev++) {
+        if (check_mkey_revision(rev)) {
+            g_determined_mkey_revision = 1;
+            g_mkey_revision = rev;
+            break;
+        }
+    }
+    
+    /* We must have determined the master key, or we're not running on a Switch. */
+    /* TODO: When panic is implemented, make this a really distinctive color. */
+    /* Maybe bright red? */
+    if (g_determined_mkey_revision == 0) {
+        panic();
+    }
+}
+
+unsigned int mkey_get_revision(void) {
+    if (g_determined_mkey_revision == 0) {
+        panic();
+    }
+    
+    return g_mkey_revision;
+}
+
+unsigned int mkey_get_keyslot(unsigned int revision) {
+    if (g_determined_mkey_revision == 0 || revision >= MASTERKEY_REVISION_MAX) {
+        panic();
+    }
+    
+    if (revision > g_mkey_revision) {
+        panic();
+    }
+    
+    if (revision == g_mkey_revision) {
+        return KEYSLOT_SWITCH_MASTERKEY;
+    } else {
+        /* Load into a temp keyslot. */
+        set_aes_keyslot(KEYSLOT_SWITCH_TEMPKEY, g_old_masterkeys[revision], 0x10);
+        return KEYSLOT_SWITCH_TEMPKEY;
+    }
+}

exosphere/masterkey.h

@@ -0,0 +1,16 @@
+#ifndef EXOSPHERE_MASTERKEY_H
+#define EXOSPHERE_MASTERKEY_H
+
+/* This is glue code to enable master key support across versions. */
+
+/* TODO: Update to 0x5 on release of new master key. */
+#define MASTERKEY_REVISION_MAX 0x4
+
+/* This should be called early on in initialization. */
+void mkey_detect_revision(void);
+
+unsigned int mkey_get_revision(void);
+
+unsigned int mkey_get_keyslot(unsigned int revision);
+
+#endif

exosphere/se.h

@@ -6,6 +6,15 @@
 
 /* Exosphere driver for the Tegra X1 security engine. */
 
+#define KEYSLOT_SWITCH_TEMPKEY 0x9
+#define KEYSLOT_SWITCH_SESSIONKEY 0xA
+#define KEYSLOT_SWITCH_RNGKEY 0xB
+#define KEYSLOT_SWITCH_MASTERKEY 0xC
+#define KEYSLOT_SWITCH_DEVICEKEY 0xD
+
+/* This key was added in 4.0.0. */
+#define KEYSLOT_SWITCH_NEWDEVICEKEY 0xF
+
 #define KEYSLOT_AES_MAX 0x10
 #define KEYSLOT_RSA_MAX 0x2
 

exosphere/smc_api.c

@@ -108,8 +108,7 @@ uint64_t try_set_smc_callback(uint32_t (*callback)(void *, uint64_t)) {
         return 0;
     }
     
-    /* TODO: Keyslot defines. */
-    se_generate_random(0xB, &key, sizeof(uint64_t));
+    se_generate_random(KEYSLOT_SWITCH_RNGKEY, &key, sizeof(uint64_t));
     g_smc_callback_key = key;
     g_smc_callback = callback;
     return key;

exosphere/smc_user.c

@@ -2,6 +2,7 @@
 
 #include "utils.h"
 #include "cache.h"
+#include "masterkey.h"
 #include "smc_api.h"
 #include "smc_user.h"
 #include "se.h"
@@ -88,10 +89,10 @@ uint32_t user_load_aes_key(smc_args_t *args) {
     wrapped_key[1] = args->X[5];
     
     /* TODO: Unseal the kek. */
-    set_aes_keyslot(9, sealed_kek, 0x10);
+    set_aes_keyslot(KEYSLOT_SWITCH_TEMPKEY, sealed_kek, 0x10);
     
     /* Unwrap the key. */
-    decrypt_data_into_keyslot(keyslot, 9, wrapped_key, 0x10);
+    decrypt_data_into_keyslot(keyslot, KEYSLOT_SWITCH_TEMPKEY, wrapped_key, 0x10);
     return 0;
 }
 
@@ -221,7 +222,9 @@ uint32_t user_unwrap_rsa_wrapped_titlekey(smc_args_t *args) {
     void *user_modulus = (void *)args->X[2];
     unsigned int master_key_rev = (unsigned int)args->X[7];
     
-    /* TODO: Validate Master Key Revision. */
+    if (master_key_rev >= MASTERKEY_REVISION_MAX) {
+        return 2;
+    }
 
     /* Copy user data into secure memory. */
     if (upage_init(&page_ref, user_wrapped_key) == 0) {
@@ -277,7 +280,10 @@ uint32_t user_unwrap_aes_wrapped_titlekey(smc_args_t *args) {
     unsigned int master_key_rev = (unsigned int)args->X[3];
     
     
-    /* TODO: Validate Master Key Revision. */
+    if (master_key_rev >= MASTERKEY_REVISION_MAX) {
+        return 2;
+    }
+    
     tkey_set_master_key_rev(master_key_rev);
     
     
@@ -286,5 +292,4 @@ uint32_t user_unwrap_aes_wrapped_titlekey(smc_args_t *args) {
     
     args->X[1] = sealed_titlekey[0];
     args->X[2] = sealed_titlekey[1];
-
 }