hekate/nyx/nyx_gui/storage/nx_emmc_bis.c

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/*
* eMMC BIS driver for Nintendo Switch
*
* Copyright (c) 2019-2020 shchmue
* Copyright (c) 2019-2021 CTCaer
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*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* 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 <string.h>
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#include <bdk.h>
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#include "../storage/nx_emmc.h"
#define BIS_CLUSTER_SECTORS 32
#define BIS_CLUSTER_SIZE 16384
#define BIS_CACHE_MAX_ENTRIES 16384
#define BIS_CACHE_LOOKUP_TBL_EMPTY_ENTRY -1
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typedef struct _cluster_cache_t
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{
u32 cluster_idx; // Index of the cluster in the partition.
bool dirty; // Has been modified without write-back flag.
u8 data[BIS_CLUSTER_SIZE]; // The cached cluster itself. Aligned to 8 bytes for DMA engine.
} cluster_cache_t;
typedef struct _bis_cache_t
{
bool full;
bool enabled;
u32 dirty_cnt;
u32 top_idx;
u8 dma_buff[BIS_CLUSTER_SIZE]; // Aligned to 8 bytes for DMA engine.
cluster_cache_t clusters[];
} bis_cache_t;
static u8 ks_crypt = 0;
static u8 ks_tweak = 0;
static u32 emu_offset = 0;
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static emmc_part_t *system_part = NULL;
static u32 *cache_lookup_tbl = (u32 *)NX_BIS_LOOKUP_ADDR;
static bis_cache_t *bis_cache = (bis_cache_t *)NX_BIS_CACHE_ADDR;
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static void _gf256_mul_x_le(void *block)
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{
u32 *pdata = (u32 *)block;
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u32 carry = 0;
for (u32 i = 0; i < 4; i++)
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{
u32 b = pdata[i];
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pdata[i] = (b << 1) | carry;
carry = b >> 31;
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}
if (carry)
pdata[0x0] ^= 0x87;
}
static int _nx_aes_xts_crypt_sec(u32 tweak_ks, u32 crypt_ks, u32 enc, u8 *tweak, bool regen_tweak, u32 tweak_exp, u64 sec, void *dst, void *src, u32 sec_size)
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{
u32 *pdst = (u32 *)dst;
u32 *psrc = (u32 *)src;
u32 *ptweak = (u32 *)tweak;
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if (regen_tweak)
{
for (int i = 0xF; i >= 0; i--)
{
tweak[i] = sec & 0xFF;
sec >>= 8;
}
if (!se_aes_crypt_block_ecb(tweak_ks, ENCRYPT, tweak, tweak))
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return 0;
}
// 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++)
_gf256_mul_x_le(tweak);
u8 orig_tweak[SE_KEY_128_SIZE] __attribute__((aligned(4)));
memcpy(orig_tweak, tweak, SE_KEY_128_SIZE);
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// We are assuming a 16 sector aligned size in this implementation.
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for (u32 i = 0; i < (sec_size >> 4); i++)
{
for (u32 j = 0; j < 4; j++)
pdst[j] = psrc[j] ^ ptweak[j];
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_gf256_mul_x_le(tweak);
psrc += 4;
pdst += 4;
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}
if (!se_aes_crypt_ecb(crypt_ks, enc, dst, sec_size, dst, sec_size))
return 0;
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pdst = (u32 *)dst;
ptweak = (u32 *)orig_tweak;
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for (u32 i = 0; i < (sec_size >> 4); i++)
{
for (u32 j = 0; j < 4; j++)
pdst[j] = pdst[j] ^ ptweak[j];
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_gf256_mul_x_le(orig_tweak);
pdst += 4;
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}
return 1;
}
static int nx_emmc_bis_write_block(u32 sector, u32 count, void *buff, bool flush)
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{
if (!system_part)
return 3; // Not ready.
int res;
u8 tweak[SE_KEY_128_SIZE] __attribute__((aligned(4)));
u32 cluster = sector / BIS_CLUSTER_SECTORS;
u32 aligned_sector = cluster * BIS_CLUSTER_SECTORS;
u32 sector_in_cluster = sector % BIS_CLUSTER_SECTORS;
u32 lookup_idx = cache_lookup_tbl[cluster];
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bool is_cached = lookup_idx != (u32)BIS_CACHE_LOOKUP_TBL_EMPTY_ENTRY;
// Write to cached cluster.
if (is_cached)
{
if (buff)
memcpy(bis_cache->clusters[lookup_idx].data + sector_in_cluster * NX_EMMC_BLOCKSIZE, buff, count * NX_EMMC_BLOCKSIZE);
else
buff = bis_cache->clusters[lookup_idx].data;
if (!bis_cache->clusters[lookup_idx].dirty)
bis_cache->dirty_cnt++;
bis_cache->clusters[lookup_idx].dirty = true;
if (!flush)
return 0; // Success.
// Reset args to trigger a full cluster flush to emmc.
sector_in_cluster = 0;
sector = aligned_sector;
count = BIS_CLUSTER_SECTORS;
}
// Encrypt cluster.
if (!_nx_aes_xts_crypt_sec(ks_tweak, ks_crypt, 1, tweak, true, sector_in_cluster, cluster, bis_cache->dma_buff, buff, count * NX_EMMC_BLOCKSIZE))
return 1; // Encryption error.
// If not reading from cache, do a regular read and decrypt.
if (!emu_offset)
res = nx_emmc_part_write(&emmc_storage, system_part, sector, count, bis_cache->dma_buff);
else
res = sdmmc_storage_write(&sd_storage, emu_offset + system_part->lba_start + sector, count, bis_cache->dma_buff);
if (!res)
return 1; // R/W error.
// Mark cache entry not dirty if write succeeds.
if (is_cached)
{
bis_cache->clusters[lookup_idx].dirty = false;
bis_cache->dirty_cnt--;
}
return 0; // Success.
}
static void _nx_emmc_bis_cluster_cache_init(bool enable_cache)
{
u32 cache_lookup_tbl_size = (system_part->lba_end - system_part->lba_start + 1) / BIS_CLUSTER_SECTORS * sizeof(*cache_lookup_tbl);
// Clear cache header.
memset(bis_cache, 0, sizeof(bis_cache_t));
// Clear cluster lookup table.
memset(cache_lookup_tbl, BIS_CACHE_LOOKUP_TBL_EMPTY_ENTRY, cache_lookup_tbl_size);
// Enable cache.
bis_cache->enabled = enable_cache;
}
static void _nx_emmc_bis_flush_cache()
{
if (!bis_cache->enabled || !bis_cache->dirty_cnt)
return;
for (u32 i = 0; i < bis_cache->top_idx && bis_cache->dirty_cnt; i++)
{
if (bis_cache->clusters[i].dirty) {
nx_emmc_bis_write_block(bis_cache->clusters[i].cluster_idx * BIS_CLUSTER_SECTORS, BIS_CLUSTER_SECTORS, NULL, true);
bis_cache->dirty_cnt--;
}
}
_nx_emmc_bis_cluster_cache_init(true);
}
static int nx_emmc_bis_read_block_normal(u32 sector, u32 count, void *buff)
{
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static u32 prev_cluster = -1;
static u32 prev_sector = 0;
static u8 tweak[SE_KEY_128_SIZE] __attribute__((aligned(4)));
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int res;
bool regen_tweak = true;
u32 tweak_exp = 0;
u32 cluster = sector / BIS_CLUSTER_SECTORS;
u32 sector_in_cluster = sector % BIS_CLUSTER_SECTORS;
// If not reading from cache, do a regular read and decrypt.
if (!emu_offset)
res = nx_emmc_part_read(&emmc_storage, system_part, sector, count, bis_cache->dma_buff);
else
res = sdmmc_storage_read(&sd_storage, emu_offset + system_part->lba_start + sector, count, bis_cache->dma_buff);
if (!res)
return 1; // R/W error.
if (prev_cluster != cluster) // Sector in different cluster than last read.
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{
prev_cluster = cluster;
tweak_exp = sector_in_cluster;
}
else if (sector > prev_sector) // Sector in same cluster and past last sector.
{
// Calculates the new tweak using the saved one, reducing expensive _gf256_mul_x_le calls.
tweak_exp = sector - prev_sector - 1;
regen_tweak = false;
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}
else // Sector in same cluster and before or same as last sector.
tweak_exp = sector_in_cluster;
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// Maximum one cluster (1 XTS crypto block 16KB).
if (!_nx_aes_xts_crypt_sec(ks_tweak, ks_crypt, 0, tweak, regen_tweak, tweak_exp, prev_cluster, buff, bis_cache->dma_buff, count * NX_EMMC_BLOCKSIZE))
return 1; // R/W error.
prev_sector = sector + count - 1;
return 0; // Success.
}
static int nx_emmc_bis_read_block_cached(u32 sector, u32 count, void *buff)
{
int res;
u8 cache_tweak[SE_KEY_128_SIZE] __attribute__((aligned(4)));
u32 cluster = sector / BIS_CLUSTER_SECTORS;
u32 cluster_sector = cluster * BIS_CLUSTER_SECTORS;
u32 sector_in_cluster = sector % BIS_CLUSTER_SECTORS;
u32 lookup_idx = cache_lookup_tbl[cluster];
// Read from cached cluster.
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if (lookup_idx != (u32)BIS_CACHE_LOOKUP_TBL_EMPTY_ENTRY)
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{
memcpy(buff, bis_cache->clusters[lookup_idx].data + sector_in_cluster * NX_EMMC_BLOCKSIZE, count * NX_EMMC_BLOCKSIZE);
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return 0; // Success.
}
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// Flush cache if full.
if (bis_cache->top_idx >= BIS_CACHE_MAX_ENTRIES)
_nx_emmc_bis_flush_cache();
// Set new cached cluster parameters.
bis_cache->clusters[bis_cache->top_idx].cluster_idx = cluster;
bis_cache->clusters[bis_cache->top_idx].dirty = false;
cache_lookup_tbl[cluster] = bis_cache->top_idx;
// Read the whole cluster the sector resides in.
if (!emu_offset)
res = nx_emmc_part_read(&emmc_storage, system_part, cluster_sector, BIS_CLUSTER_SECTORS, bis_cache->dma_buff);
else
res = sdmmc_storage_read(&sd_storage, emu_offset + system_part->lba_start + cluster_sector, BIS_CLUSTER_SECTORS, bis_cache->dma_buff);
if (!res)
return 1; // R/W error.
// Decrypt cluster.
if (!_nx_aes_xts_crypt_sec(ks_tweak, ks_crypt, 0, cache_tweak, true, 0, cluster, bis_cache->dma_buff, bis_cache->dma_buff, BIS_CLUSTER_SIZE))
return 1; // Decryption error.
// Copy to cluster cache.
memcpy(bis_cache->clusters[bis_cache->top_idx].data, bis_cache->dma_buff, BIS_CLUSTER_SIZE);
memcpy(buff, bis_cache->dma_buff + sector_in_cluster * NX_EMMC_BLOCKSIZE, count * NX_EMMC_BLOCKSIZE);
// Increment cache count.
bis_cache->top_idx++;
return 0; // Success.
}
static int nx_emmc_bis_read_block(u32 sector, u32 count, void *buff)
{
if (!system_part)
return 3; // Not ready.
if (bis_cache->enabled)
return nx_emmc_bis_read_block_cached(sector, count, buff);
else
return nx_emmc_bis_read_block_normal(sector, count, buff);
}
int nx_emmc_bis_read(u32 sector, u32 count, void *buff)
{
u8 *buf = (u8 *)buff;
u32 curr_sct = sector;
while (count)
{
u32 sct_cnt = MIN(count, BIS_CLUSTER_SECTORS);
if (nx_emmc_bis_read_block(curr_sct, sct_cnt, buf))
return 0;
count -= sct_cnt;
curr_sct += sct_cnt;
buf += sct_cnt * NX_EMMC_BLOCKSIZE;
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}
return 1;
}
int nx_emmc_bis_write(u32 sector, u32 count, void *buff)
{
u8 *buf = (u8 *)buff;
u32 curr_sct = sector;
while (count)
{
u32 sct_cnt = MIN(count, BIS_CLUSTER_SECTORS);
if (nx_emmc_bis_write_block(curr_sct, sct_cnt, buf, false))
return 0;
count -= sct_cnt;
curr_sct += sct_cnt;
buf += sct_cnt * NX_EMMC_BLOCKSIZE;
}
return 1;
}
void nx_emmc_bis_init(emmc_part_t *part, bool enable_cache, u32 emummc_offset)
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{
system_part = part;
emu_offset = emummc_offset;
_nx_emmc_bis_cluster_cache_init(enable_cache);
if (!strcmp(part->name, "PRODINFO") || !strcmp(part->name, "PRODINFOF"))
{
ks_crypt = 0;
ks_tweak = 1;
}
else if (!strcmp(part->name, "SAFE"))
{
ks_crypt = 2;
ks_tweak = 3;
}
else if (!strcmp(part->name, "SYSTEM") || !strcmp(part->name, "USER"))
{
ks_crypt = 4;
ks_tweak = 5;
}
else
system_part = NULL;
}
void nx_emmc_bis_end()
{
_nx_emmc_bis_flush_cache();
system_part = NULL;
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}