smcGenerateAesKek + Key sealing.

exosphere/smc_user.c

@@ -2,10 +2,12 @@
 
 #include "utils.h"
 #include "cache.h"
+#incoude "configitem.h"
 #include "masterkey.h"
 #include "smc_api.h"
 #include "smc_user.h"
 #include "se.h"
+#include "sealedkeys.h"
 #include "userpage.h"
 #include "titlekey.h"
 
@@ -73,6 +75,100 @@ uint32_t user_exp_mod(smc_args_t *args) {
     return 0;
 }
 
+uint32_t user_generate_aes_kek(smc_args_t *args) {
+    uint64_t wrapped_kek[2];
+    uint8_t kek_source[0x10];
+    uint64_t kek[2];
+    uint64_t sealed_kek[2];
+    
+    wrapped_kek[0] = args->X[1];
+    wrapped_kek[1] = args->X[2];
+    
+    unsigned int master_key_rev = (unsigned int)args->X[3];
+    
+    if (master_key_rev > 0) {
+        master_key_rev -= 1; /* GenerateAesKek offsets by one. */
+    }
+    
+    if (master_key_rev >= MASTERKEY_REVISION_MAX) {
+        return 2;
+    }
+    
+    uint64_t packed_options = args->X[4];
+    if (packed_options > 0xFF) {
+        return 2;
+    }
+    
+    /* Switched the output based on how the system was booted. */
+    uint8_t mask_id = (uint8_t)((packed_options >> 1) & 3);
+    
+    /* Switches the output based on how it will be used. */
+    uint8_t usecase = (uint8_t)((packed_options >> 5) & 3);
+    
+    /* Switched the output based on whether it should be console unique. */
+    int is_personalized = (int)(packed_options & 1);
+    
+    uint64_t is_recovery_boot = configitem_is_recovery_boot();
+    
+    /* Mask 2 is only allowed when booted normally. */
+    if (mask_id == 2 && is_recovery_boot == 0) {
+        return 2;
+    }
+    /* Mask 1 is only allowed when booted from recovery. */
+    if (mask_id == 1 && is_recovery_boot != 0) {
+        return 2;
+    }
+    
+    /* Masks 0, 3 are allowed all the time. */
+    
+    const uint8_t kek_seeds[4][0x10] = {
+        {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
+        {0xA2, 0xAB, 0xBF, 0x9C, 0x92, 0x2F, 0xBB, 0xE3, 0x78, 0x79, 0x9B, 0xC0, 0xCC, 0xEA, 0xA5, 0x74},
+        {0x57, 0xE2, 0xD9, 0x45, 0xE4, 0x92, 0xF4, 0xFD, 0xC3, 0xF9, 0x86, 0x38, 0x89, 0x78, 0x9F, 0x3C},
+        {0xE5, 0x4D, 0x9A, 0x02, 0xF0, 0x4F, 0x5F, 0xA8, 0xAD, 0x76, 0x0A, 0xF6, 0x32, 0x95, 0x59, 0xBB}
+    };
+    const uint8_t kek_masks[4][0x10] = {
+        {0x4D, 0x87, 0x09, 0x86, 0xC4, 0x5D, 0x20, 0x72, 0x2F, 0xBA, 0x10, 0x53, 0xDA, 0x92, 0xE8, 0xA9},
+        {0x25, 0x03, 0x31, 0xFB, 0x25, 0x26, 0x0B, 0x79, 0x8C, 0x80, 0xD2, 0x69, 0x98, 0xE2, 0x22, 0x77},
+        {0x76, 0x14, 0x1D, 0x34, 0x93, 0x2D, 0xE1, 0x84, 0x24, 0x7B, 0x66, 0x65, 0x55, 0x04, 0x65, 0x81},
+        {0xAF, 0x3D, 0xB7, 0xF3, 0x08, 0xA2, 0xD8, 0xA2, 0x08, 0xCA, 0x18, 0xA8, 0x69, 0x46, 0xC9, 0x0B}
+    };
+    
+    /* Create kek source. */
+    for (unsigned int i = 0; i < 0x10; i++) {
+        kek_source[i] = kek_seeds[usecase][i] ^ kek_masks[mask_id][i];
+    }
+    
+    unsigned int keyslot;
+    if (is_personalized) {
+        /* Behavior changed in 4.0.0. */
+        if (mkey_get_revision() >= 4) {
+            if (master_key_rev >= 1) {
+                keyslot = KEYSLOT_SWITCH_DEVICEKEY; /* New device key, 4.x. */
+            } else {
+                keyslot = KEYSLOT_SWITCH_4XOLDDEVICEKEY; /* Old device key, 4.x. */
+            }
+        } else {
+            keyslot = KEYSLOT_SWITCH_DEVICEKEY;
+        }
+    } else {
+        keyslot = mkey_get_keyslot(master_key_rev);
+    }
+    
+    /* Derive kek. */
+    decrypt_data_into_keyslot(KEYSLOT_SWITCH_TEMPKEY, keyslot, kek_source, 0x10);
+    se_aes_ecb_decrypt_block(KEYSLOT_SWITCH_TEMPKEY, kek, 0x10, wrapped_kek, 0x10);
+    
+    
+    /* Seal kek. */
+    seal_key(sealed_kek, 0x10, kek, 0x10, usecase);
+    
+    args->X[1] = sealed_kek[0];
+    args->X[2] = sealed_kek[1];
+    
+    return 0;
+}
+
 uint32_t user_load_aes_key(smc_args_t *args) {
     uint64_t sealed_kek[2];
     uint64_t wrapped_key[2];
@@ -89,7 +185,7 @@ uint32_t user_load_aes_key(smc_args_t *args) {
     wrapped_key[1] = args->X[5];
     
     /* TODO: Unseal the kek. */
-    set_aes_keyslot(KEYSLOT_SWITCH_TEMPKEY, sealed_kek, 0x10);
+    unseal_key(KEYSLOT_SWITCH_TEMPKEY, sealed_kek, 0x10, CRYPTOUSECASE_AES);
     
     /* Unwrap the key. */
     decrypt_data_into_keyslot(keyslot, KEYSLOT_SWITCH_TEMPKEY, wrapped_key, 0x10);
@@ -265,7 +361,7 @@ uint32_t user_load_titlekey(smc_args_t *args) {
     sealed_titlekey[1] = args->X[3];
     
     /* Unseal the key. */
-    tkey_unseal(keyslot, sealed_titlekey, 0x10);
+    unseal_titlekey(keyslot, sealed_titlekey, 0x10);
     return 0;
 
 }
@@ -288,7 +384,7 @@ uint32_t user_unwrap_aes_wrapped_titlekey(smc_args_t *args) {
     
     
     tkey_aes_unwrap(titlekey, 0x10, aes_wrapped_titlekey, 0x10);
-    tkey_seal(sealed_titlekey, 0x10, titlekey, 0x10);
+    seal_titlekey(sealed_titlekey, 0x10, titlekey, 0x10);
     
     args->X[1] = sealed_titlekey[0];
     args->X[2] = sealed_titlekey[1];