exosphere: correct reencryption of rsa private keys

This commit is contained in:
Michael Scire 2020-04-24 17:36:37 -07:00
parent 524da78b0e
commit 7bc0250cea

View File

@ -13,7 +13,7 @@
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdint.h>
#include <string.h>
@ -83,7 +83,7 @@ static void ghash(void *dst, const void *data, size_t data_size, const void *j_b
/* H = aes_ecb_encrypt(zeroes) */
se_aes_128_ecb_encrypt_block(KEYSLOT_SWITCH_TEMPKEY, h, 0x10, x, 0x10);
size_t total_size = data_size;
while (data_size >= 0x10) {
@ -103,7 +103,7 @@ static void ghash(void *dst, const void *data, size_t data_size, const void *j_b
if (data_size & 0xF) {
gf128_mul(x, x, h);
}
uint64_t xor_size = total_size << 3;
xor_size = __builtin_bswap64(xor_size);
@ -113,9 +113,9 @@ static void ghash(void *dst, const void *data, size_t data_size, const void *j_b
} else {
p_x[1] ^= xor_size;
}
gf128_mul(x, x, h);
/* If final output block, XOR with encrypted J block. */
if (encrypt) {
se_aes_128_ecb_encrypt_block(KEYSLOT_SWITCH_TEMPKEY, h, 0x10, j_block, 0x10);
@ -140,22 +140,22 @@ size_t gcm_decrypt_key(void *dst, size_t dst_size, const void *src, size_t src_s
generic_panic();
}
}
uint8_t intermediate_buf[0x400] = {0};
/* Unwrap the key */
unseal_key(KEYSLOT_SWITCH_TEMPKEY, sealed_kek, kek_size, usecase);
decrypt_data_into_keyslot(KEYSLOT_SWITCH_TEMPKEY, KEYSLOT_SWITCH_TEMPKEY, wrapped_key, key_size);
/* Decrypt the GCM keypair, AES-CTR with CTR = blob[:0x10]. */
se_aes_ctr_crypt(KEYSLOT_SWITCH_TEMPKEY, intermediate_buf, dst_size, src + 0x10, src_size - 0x10, src, 0x10);
if (!is_personalized) {
/* Devkit non-personalized keys have no further authentication. */
memcpy(dst, intermediate_buf, src_size - 0x10);
memset(intermediate_buf, 0, sizeof(intermediate_buf));
return src_size - 0x10;
}
}
/* J = GHASH(CTR); */
uint8_t j_block[0x10];
@ -166,7 +166,7 @@ size_t gcm_decrypt_key(void *dst, size_t dst_size, const void *src, size_t src_s
/* It is supposed to be over the ciphertext. */
uint8_t calc_mac[0x10];
ghash(calc_mac, intermediate_buf, src_size - 0x20, j_block, true);
/* Const-time memcmp. */
const uint8_t *src_bytes = src;
int different = 0;
@ -184,7 +184,7 @@ size_t gcm_decrypt_key(void *dst, size_t dst_size, const void *src, size_t src_s
if (out_deviceid_high != NULL) {
*out_deviceid_high = intermediate_buf[src_size - 0x28];
}
memcpy(dst, intermediate_buf, src_size - 0x30);
memset(intermediate_buf, 0, sizeof(intermediate_buf));
return src_size - 0x30;
@ -205,10 +205,12 @@ void gcm_encrypt_key(void *dst, size_t dst_size, const void *src, size_t src_siz
se_generate_random(KEYSLOT_SWITCH_RNGKEY, intermediate_buf, 0x10);
flush_dcache_range(intermediate_buf, intermediate_buf + 0x10);
/* Copy in the src. */
memcpy(intermediate_buf + 0x10, src, src_size);
/* Write Device ID. */
write64be(intermediate_buf, src_size + 0x18, fuse_get_device_id() | (deviceid_high << 56));
/* J = GHASH(CTR); */
uint8_t j_block[0x10];
ghash(j_block, intermediate_buf, 0x10, NULL, false);