257 lines
7.1 KiB
C
257 lines
7.1 KiB
C
/*
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* eMMC BIS driver for Nintendo Switch
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*
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* Copyright (c) 2019 shchmue
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* Copyright (c) 2019-2020 CTCaer
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <string.h>
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#include <memory_map.h>
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#include <sec/se.h>
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#include "../storage/nx_emmc.h"
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#include <storage/sdmmc.h>
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#include <utils/types.h>
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#define MAX_CLUSTER_CACHE_ENTRIES 128
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#define CLUSTER_LOOKUP_EMPTY_ENTRY 0xFFFFFFFF
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#define XTS_CLUSTER_SIZE 0x4000
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#define SECTORS_PER_CLUSTER 0x20
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typedef struct
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{
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u32 cluster_num; // index of the cluster in the partition
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u32 visit_count; // used for debugging/access analysis
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u8 dirty; // has been modified without writeback flag
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u8 align[7];
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u8 cluster[XTS_CLUSTER_SIZE]; // the cached cluster itself
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} cluster_cache_t;
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static u8 ks_crypt = 0;
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static u8 ks_tweak = 0;
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static u32 cluster_cache_end_index = 0;
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static emmc_part_t *system_part = NULL;
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static u8 *emmc_buffer = (u8 *)NX_BIS_CACHE_ADDR;
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static cluster_cache_t *cluster_cache = (cluster_cache_t *)(NX_BIS_CACHE_ADDR + XTS_CLUSTER_SIZE);
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static u32 *cluster_lookup = (u32 *)(NX_BIS_CACHE_ADDR + XTS_CLUSTER_SIZE + MAX_CLUSTER_CACHE_ENTRIES * sizeof(cluster_cache_t));
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static bool lock_cluster_cache = false;
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static void _gf256_mul_x_le(void *block)
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{
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u32 *pdata = (u32 *)block;
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u32 carry = 0;
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for (u32 i = 0; i < 4; i++)
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{
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u32 b = pdata[i];
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pdata[i] = (b << 1) | carry;
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carry = b >> 31;
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}
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if (carry)
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pdata[0x0] ^= 0x87;
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}
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static int _nx_aes_xts_crypt_sec(u32 tweak_ks, u32 crypt_ks, u32 enc, u8 *tweak, bool regen_tweak, u32 tweak_exp, u32 sec, void *dst, const void *src, u32 sec_size)
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{
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u32 *pdst = (u32 *)dst;
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u32 *psrc = (u32 *)src;
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u32 *ptweak = (u32 *)tweak;
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if (regen_tweak)
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{
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for (int i = 0xF; i >= 0; i--)
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{
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tweak[i] = sec & 0xFF;
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sec >>= 8;
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}
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if (!se_aes_crypt_block_ecb(tweak_ks, 1, tweak, tweak))
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return 0;
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}
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// tweak_exp allows us to use a saved tweak to reduce _gf256_mul_x_le calls.
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for (u32 i = 0; i < (tweak_exp << 5); i++)
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_gf256_mul_x_le(tweak);
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u8 orig_tweak[0x10];
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memcpy(orig_tweak, tweak, 0x10);
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// We are assuming a 0x10-aligned sector size in this implementation.
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for (u32 i = 0; i < (sec_size >> 4); i++)
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{
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for (u32 j = 0; j < 4; j++)
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pdst[j] = psrc[j] ^ ptweak[j];
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_gf256_mul_x_le(tweak);
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psrc += 4;
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pdst += 4;
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}
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if (!se_aes_crypt_ecb(crypt_ks, enc, dst, sec_size, dst, sec_size))
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return 0;
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pdst = (u32 *)dst;
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ptweak = (u32 *)orig_tweak;
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for (u32 i = 0; i < (sec_size >> 4); i++)
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{
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for (u32 j = 0; j < 4; j++)
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pdst[j] = pdst[j] ^ ptweak[j];
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_gf256_mul_x_le(orig_tweak);
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pdst += 4;
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}
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return 1;
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}
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static int nx_emmc_bis_read_block(u32 sector, u32 count, void *buff)
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{
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if (!system_part)
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return 3; // Not ready.
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static u32 prev_cluster = -1;
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static u32 prev_sector = 0;
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static u8 tweak[0x10];
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u32 tweak_exp = 0;
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bool regen_tweak = true;
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u32 cluster = sector / SECTORS_PER_CLUSTER;
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u32 aligned_sector = cluster * SECTORS_PER_CLUSTER;
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u32 sector_index_in_cluster = sector % SECTORS_PER_CLUSTER;
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u32 cluster_lookup_index = cluster_lookup[cluster];
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if (cluster_lookup_index != CLUSTER_LOOKUP_EMPTY_ENTRY)
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{
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memcpy(buff, cluster_cache[cluster_lookup_index].cluster + sector_index_in_cluster * NX_EMMC_BLOCKSIZE, count * NX_EMMC_BLOCKSIZE);
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cluster_cache[cluster_lookup_index].visit_count++;
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prev_sector = sector + count - 1;
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prev_cluster = cluster;
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return 0; // Success.
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}
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// Only cache single-sector reads as these are most likely to be repeated, such as boot block and FAT directory tables.
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if (count == 1 &&
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!lock_cluster_cache &&
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cluster_cache_end_index < MAX_CLUSTER_CACHE_ENTRIES &&
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cluster_lookup_index == CLUSTER_LOOKUP_EMPTY_ENTRY)
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{
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cluster_cache[cluster_cache_end_index].cluster_num = cluster;
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cluster_cache[cluster_cache_end_index].visit_count = 1;
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cluster_cache[cluster_cache_end_index].dirty = 0;
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cluster_lookup[cluster] = cluster_cache_end_index;
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// Read and decrypt the whole cluster the sector resides in.
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if (!nx_emmc_part_read(&emmc_storage, system_part, aligned_sector, SECTORS_PER_CLUSTER, emmc_buffer))
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return 1; // R/W error.
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if (!_nx_aes_xts_crypt_sec(ks_tweak, ks_crypt, 0, tweak, true, 0, cluster, emmc_buffer, emmc_buffer, XTS_CLUSTER_SIZE))
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return 1; // R/W error.
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// Copy to cluster cache.
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memcpy(cluster_cache[cluster_cache_end_index].cluster, emmc_buffer, XTS_CLUSTER_SIZE);
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memcpy(buff, emmc_buffer + sector_index_in_cluster * NX_EMMC_BLOCKSIZE, NX_EMMC_BLOCKSIZE);
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prev_cluster = -1;
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prev_sector = 0;
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cluster_cache_end_index++;
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return 0; // Success.
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}
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// If not reading from or writing to cache, do a regular read and decrypt.
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if (!nx_emmc_part_read(&emmc_storage, system_part, sector, count, buff))
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return 1; // R/W error.
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if (prev_cluster != cluster) // Sector in different cluster than last read.
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{
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prev_cluster = cluster;
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tweak_exp = sector_index_in_cluster;
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}
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else if (sector > prev_sector) // Sector in same cluster and past last sector.
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{
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// Calculates the new tweak using the saved one, reducing expensive _gf256_mul_x_le calls.
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tweak_exp = sector - prev_sector - 1;
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regen_tweak = false;
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}
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else // Sector in same cluster and before or same as last sector.
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tweak_exp = sector_index_in_cluster;
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// Maximum one cluster (1 XTS crypto block 16KB).
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if (!_nx_aes_xts_crypt_sec(ks_tweak, ks_crypt, 0, tweak, regen_tweak, tweak_exp, prev_cluster, buff, buff, count * NX_EMMC_BLOCKSIZE))
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return 1; // R/W error.
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prev_sector = sector + count - 1;
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return 0; // Success.
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}
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int nx_emmc_bis_read(u32 sector, u32 count, void *buff)
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{
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int res = 1;
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u8 *buf = (u8 *)buff;
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u32 curr_sct = sector;
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while (count)
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{
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u32 sct_cnt = MIN(count, 0x20);
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res = nx_emmc_bis_read_block(curr_sct, sct_cnt, buf);
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if (res)
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return 1;
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count -= sct_cnt;
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curr_sct += sct_cnt;
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buf += NX_EMMC_BLOCKSIZE * sct_cnt;
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}
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return res;
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}
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void nx_emmc_bis_cluster_cache_init()
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{
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// Clear cluster lookup table and reset end index.
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memset(cluster_lookup, -1, (system_part->lba_end - system_part->lba_start + 1) / SECTORS_PER_CLUSTER * sizeof(*cluster_lookup));
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cluster_cache_end_index = 0;
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lock_cluster_cache = false;
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}
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void nx_emmc_bis_init(emmc_part_t *part)
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{
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system_part = part;
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nx_emmc_bis_cluster_cache_init();
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switch (part->index)
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{
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case 0: // PRODINFO.
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case 1: // PRODINFOF.
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ks_crypt = 0;
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ks_tweak = 1;
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break;
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case 8: // SAFE.
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ks_crypt = 2;
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ks_tweak = 3;
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break;
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case 9: // SYSTEM.
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case 10: // USER.
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ks_crypt = 4;
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ks_tweak = 5;
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break;
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}
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}
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// Set cluster cache lock according to arg.
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void nx_emmc_bis_cache_lock(bool lock)
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{
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lock_cluster_cache = lock;
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}
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