smcGenerateAesKek + Key sealing.

This commit is contained in:
Michael Scire 2018-02-20 01:02:01 -08:00
parent 07f9e9500e
commit 4030c6eb20
7 changed files with 201 additions and 6 deletions

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@ -13,6 +13,15 @@ uint32_t configitem_set(enum ConfigItem item, uint64_t value) {
g_battery_profile = ((int)(value != 0)) & 1; g_battery_profile = ((int)(value != 0)) & 1;
} }
uint64_t configitem_is_recovery_boot(void) {
uint64_t is_recovery_boot;
if (configitem_get(CONFIGITEM_ISRECOVERYBOOT, &is_recovery_boot) != 0) {
panic();
}
return is_recovery_boot;
}
uint32_t configitem_get(enum ConfigItem item, uint64_t *p_outvalue) { uint32_t configitem_get(enum ConfigItem item, uint64_t *p_outvalue) {
uint32_t result = 0; uint32_t result = 0;
switch (item) { switch (item) {

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@ -23,4 +23,6 @@ enum ConfigItem {
uint32_t configitem_set(enum ConfigItem item, uint64_t value); uint32_t configitem_set(enum ConfigItem item, uint64_t value);
uint32_t configitem_get(enum ConfigItem item, uint64_t *p_outvalue); uint32_t configitem_get(enum ConfigItem item, uint64_t *p_outvalue);
uint64_t configitem_is_recovery_boot(void);
#endif #endif

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@ -12,8 +12,8 @@
#define KEYSLOT_SWITCH_MASTERKEY 0xC #define KEYSLOT_SWITCH_MASTERKEY 0xC
#define KEYSLOT_SWITCH_DEVICEKEY 0xD #define KEYSLOT_SWITCH_DEVICEKEY 0xD
/* This key was added in 4.0.0. */ /* This keyslot was added in 4.0.0. */
#define KEYSLOT_SWITCH_NEWDEVICEKEY 0xF #define KEYSLOT_SWITCH_4XOLDDEVICEKEY 0xF
#define KEYSLOT_AES_MAX 0x10 #define KEYSLOT_AES_MAX 0x10
#define KEYSLOT_RSA_MAX 0x2 #define KEYSLOT_RSA_MAX 0x2

63
exosphere/sealedkeys.c Normal file
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@ -0,0 +1,63 @@
#include <stdint.h>
#include "utils.h"
#include "sealedkeys.h"
#include "se.h"
const uint8_t g_titlekey_seal_key_source[0x10] = {
0xCB, 0xB7, 0x6E, 0x38, 0xA1, 0xCB, 0x77, 0x0F, 0xB2, 0xA5, 0xB2, 0x9D, 0xD8, 0x56, 0x9F, 0x76
};
const uint8_t g_sealed_key_sources[CRYPTOUSECASE_MAX][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}
};
void seal_key_internal(void *dst, const void *src, const uint8_t *seal_key_source) {
decrypt_data_into_keyslot(KEYSLOT_SWITCH_TEMPKEY, KEYSLOT_SWITCH_SESSIONKEY, seal_key_source, 0x10);
se_aes_ecb_encrypt_block(KEYSLOT_SWITCH_TEMPKEY, dst, 0x10, src, 0x10);
}
void unseal_key_internal(unsigned int keyslot, const void *src, const uint8_t *seal_key_source) {
decrypt_data_into_keyslot(KEYSLOT_SWITCH_TEMPKEY, KEYSLOT_SWITCH_SESSIONKEY, seal_key_source, 0x10);
decrypt_data_into_keyslot(keyslot, KEYSLOT_SWITCH_TEMPKEY, src, 0x10);
}
void seal_titlekey(void *dst, size_t dst_size, const void *src, size_t src_size) {
if (usecase >= CRYPTOUSECASE_MAX || dst_size != 0x10 || src_size != 0x10) {
panic();
}
seal_key_internal(dst, src, g_titlekey_seal_key_source);
}
void unseal_titlekey(unsigned int keyslot, const void *src, size_t src_size) {
if (src_size != 0x10) {
panic();
}
unseal_key_internal(keyslot, src, g_titlekey_seal_key_source);
}
void seal_key(void *dst, size_t dst_size, const void *src, size_t src_size, unsigned int usecase) {
if (usecase >= CRYPTOUSECASE_MAX || dst_size != 0x10 || src_size != 0x10) {
panic();
}
seal_key_internal(dst, src, g_sealed_key_sources[usecase]);
}
void unseal_key(unsigned int keyslot, const void *src, size_t src_size, unsigned int usecase) {
if (usecase >= CRYPTOUSECASE_MAX || src_size != 0x10) {
panic();
}
seal_key_internal(dst, src, g_sealed_key_sources[usecase]);
}

21
exosphere/sealedkeys.h Normal file
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@ -0,0 +1,21 @@
#ifndef EXOSPHERE_SEALED_KEYS_H
#define EXOSPHERE_SEALED_KEYS_H
#include <stdint.h>
/* Key sealing/unsealing functionality. */
#define CRYPTOUSECASE_AES 0
#define CRYPTOUSECASE_RSAPRIVATE 1
#define CRYPTOUSECASE_RSAOAEP 2
#define CRYPTOUSECASE_RSATICKET 3
#define CRYPTOUSECASE_MAX 4
void seal_titlekey(void *dst, size_t dst_size, const void *src, size_t src_size);
void unseal_titlekey(unsigned int keyslot, const void *src, size_t src_size);
void seal_key(void *dst, size_t dst_size, const void *src, size_t src_size, unsigned int usecase);
void unseal_key(unsigned int keyslot, const void *src, size_t src_size, unsigned int usecase);
#endif

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@ -279,6 +279,10 @@ uint32_t smc_exp_mod(smc_args_t *args) {
return smc_wrapper_async(args, user_exp_mod, smc_exp_mod_get_result); return smc_wrapper_async(args, user_exp_mod, smc_exp_mod_get_result);
} }
uint32_t smc_generate_aes_kek(smc_args_t *args) {
return smc_wrapper_sync(args, user_generate_aes_kek);
}
uint32_t smc_load_aes_key(smc_args_t *args) { uint32_t smc_load_aes_key(smc_args_t *args) {
return smc_wrapper_sync(args, user_load_aes_key); return smc_wrapper_sync(args, user_load_aes_key);
} }
@ -327,7 +331,7 @@ uint32_t smc_unwrap_rsa_wrapped_titlekey_get_result(void *buf, uint64_t size) {
} }
tkey_aes_unwrap(titlekey, 0x10, aes_wrapped_titlekey, 0x10); tkey_aes_unwrap(titlekey, 0x10, aes_wrapped_titlekey, 0x10);
tkey_seal(sealed_titlekey, 0x10, titlekey, 0x10); seal_titlekey(sealed_titlekey, 0x10, titlekey, 0x10);
p_sealed_key[0] = sealed_titlekey[0]; p_sealed_key[0] = sealed_titlekey[0];
p_sealed_key[1] = sealed_titlekey[1]; p_sealed_key[1] = sealed_titlekey[1];

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@ -2,10 +2,12 @@
#include "utils.h" #include "utils.h"
#include "cache.h" #include "cache.h"
#incoude "configitem.h"
#include "masterkey.h" #include "masterkey.h"
#include "smc_api.h" #include "smc_api.h"
#include "smc_user.h" #include "smc_user.h"
#include "se.h" #include "se.h"
#include "sealedkeys.h"
#include "userpage.h" #include "userpage.h"
#include "titlekey.h" #include "titlekey.h"
@ -73,6 +75,100 @@ uint32_t user_exp_mod(smc_args_t *args) {
return 0; 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) { uint32_t user_load_aes_key(smc_args_t *args) {
uint64_t sealed_kek[2]; uint64_t sealed_kek[2];
uint64_t wrapped_key[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]; wrapped_key[1] = args->X[5];
/* TODO: Unseal the kek. */ /* 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. */ /* Unwrap the key. */
decrypt_data_into_keyslot(keyslot, KEYSLOT_SWITCH_TEMPKEY, wrapped_key, 0x10); 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]; sealed_titlekey[1] = args->X[3];
/* Unseal the key. */ /* Unseal the key. */
tkey_unseal(keyslot, sealed_titlekey, 0x10); unseal_titlekey(keyslot, sealed_titlekey, 0x10);
return 0; 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_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[1] = sealed_titlekey[0];
args->X[2] = sealed_titlekey[1]; args->X[2] = sealed_titlekey[1];