u-boot/drivers/mmc/rpmb.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright 2014, Staubli Faverges
* Pierre Aubert
*
* eMMC- Replay Protected Memory Block
* According to JEDEC Standard No. 84-A441
*/
#include <config.h>
#include <common.h>
#include <memalign.h>
#include <mmc.h>
#include <u-boot/sha256.h>
#include "mmc_private.h"
/* Request codes */
#define RPMB_REQ_KEY 1
#define RPMB_REQ_WCOUNTER 2
#define RPMB_REQ_WRITE_DATA 3
#define RPMB_REQ_READ_DATA 4
#define RPMB_REQ_STATUS 5
/* Response code */
#define RPMB_RESP_KEY 0x0100
#define RPMB_RESP_WCOUNTER 0x0200
#define RPMB_RESP_WRITE_DATA 0x0300
#define RPMB_RESP_READ_DATA 0x0400
/* Error codes */
#define RPMB_OK 0
#define RPMB_ERR_GENERAL 1
#define RPMB_ERR_AUTH 2
#define RPMB_ERR_COUNTER 3
#define RPMB_ERR_ADDRESS 4
#define RPMB_ERR_WRITE 5
#define RPMB_ERR_READ 6
#define RPMB_ERR_KEY 7
#define RPMB_ERR_CNT_EXPIRED 0x80
#define RPMB_ERR_MSK 0x7
/* Sizes of RPMB data frame */
#define RPMB_SZ_STUFF 196
#define RPMB_SZ_MAC 32
#define RPMB_SZ_DATA 256
#define RPMB_SZ_NONCE 16
#define SHA256_BLOCK_SIZE 64
/* Error messages */
static const char * const rpmb_err_msg[] = {
"",
"General failure",
"Authentication failure",
"Counter failure",
"Address failure",
"Write failure",
"Read failure",
"Authentication key not yet programmed",
};
/* Structure of RPMB data frame. */
struct s_rpmb {
unsigned char stuff[RPMB_SZ_STUFF];
unsigned char mac[RPMB_SZ_MAC];
unsigned char data[RPMB_SZ_DATA];
unsigned char nonce[RPMB_SZ_NONCE];
unsigned int write_counter;
unsigned short address;
unsigned short block_count;
unsigned short result;
unsigned short request;
};
static int mmc_set_blockcount(struct mmc *mmc, unsigned int blockcount,
bool is_rel_write)
{
struct mmc_cmd cmd = {0};
cmd.cmdidx = MMC_CMD_SET_BLOCK_COUNT;
cmd.cmdarg = blockcount & 0x0000FFFF;
if (is_rel_write)
cmd.cmdarg |= 1 << 31;
cmd.resp_type = MMC_RSP_R1;
return mmc_send_cmd(mmc, &cmd, NULL);
}
static int mmc_rpmb_request(struct mmc *mmc, const struct s_rpmb *s,
unsigned int count, bool is_rel_write)
{
struct mmc_cmd cmd = {0};
struct mmc_data data;
int ret;
ret = mmc_set_blockcount(mmc, count, is_rel_write);
if (ret) {
#ifdef CONFIG_MMC_RPMB_TRACE
printf("%s:mmc_set_blockcount-> %d\n", __func__, ret);
#endif
return 1;
}
cmd.cmdidx = MMC_CMD_WRITE_MULTIPLE_BLOCK;
cmd.cmdarg = 0;
cmd.resp_type = MMC_RSP_R1b;
data.src = (const char *)s;
data.blocks = 1;
data.blocksize = MMC_MAX_BLOCK_LEN;
data.flags = MMC_DATA_WRITE;
ret = mmc_send_cmd(mmc, &cmd, &data);
if (ret) {
#ifdef CONFIG_MMC_RPMB_TRACE
printf("%s:mmc_send_cmd-> %d\n", __func__, ret);
#endif
return 1;
}
return 0;
}
static int mmc_rpmb_response(struct mmc *mmc, struct s_rpmb *s,
unsigned short expected)
{
struct mmc_cmd cmd = {0};
struct mmc_data data;
int ret;
ret = mmc_set_blockcount(mmc, 1, false);
if (ret) {
#ifdef CONFIG_MMC_RPMB_TRACE
printf("%s:mmc_set_blockcount-> %d\n", __func__, ret);
#endif
return -1;
}
cmd.cmdidx = MMC_CMD_READ_MULTIPLE_BLOCK;
cmd.cmdarg = 0;
cmd.resp_type = MMC_RSP_R1;
data.dest = (char *)s;
data.blocks = 1;
data.blocksize = MMC_MAX_BLOCK_LEN;
data.flags = MMC_DATA_READ;
ret = mmc_send_cmd(mmc, &cmd, &data);
if (ret) {
#ifdef CONFIG_MMC_RPMB_TRACE
printf("%s:mmc_send_cmd-> %d\n", __func__, ret);
#endif
return -1;
}
/* Check the response and the status */
if (be16_to_cpu(s->request) != expected) {
#ifdef CONFIG_MMC_RPMB_TRACE
printf("%s:response= %x\n", __func__,
be16_to_cpu(s->request));
#endif
return -1;
}
ret = be16_to_cpu(s->result);
if (ret) {
printf("%s %s\n", rpmb_err_msg[ret & RPMB_ERR_MSK],
(ret & RPMB_ERR_CNT_EXPIRED) ?
"Write counter has expired" : "");
}
/* Return the status of the command */
return ret;
}
static int mmc_rpmb_status(struct mmc *mmc, unsigned short expected)
{
ALLOC_CACHE_ALIGN_BUFFER(struct s_rpmb, rpmb_frame, 1);
memset(rpmb_frame, 0, sizeof(struct s_rpmb));
rpmb_frame->request = cpu_to_be16(RPMB_REQ_STATUS);
if (mmc_rpmb_request(mmc, rpmb_frame, 1, false))
return -1;
/* Read the result */
return mmc_rpmb_response(mmc, rpmb_frame, expected);
}
static void rpmb_hmac(unsigned char *key, unsigned char *buff, int len,
unsigned char *output)
{
sha256_context ctx;
int i;
unsigned char k_ipad[SHA256_BLOCK_SIZE];
unsigned char k_opad[SHA256_BLOCK_SIZE];
sha256_starts(&ctx);
/* According to RFC 4634, the HMAC transform looks like:
SHA(K XOR opad, SHA(K XOR ipad, text))
where K is an n byte key.
ipad is the byte 0x36 repeated blocksize times
opad is the byte 0x5c repeated blocksize times
and text is the data being protected.
*/
for (i = 0; i < RPMB_SZ_MAC; i++) {
k_ipad[i] = key[i] ^ 0x36;
k_opad[i] = key[i] ^ 0x5c;
}
/* remaining pad bytes are '\0' XOR'd with ipad and opad values */
for ( ; i < SHA256_BLOCK_SIZE; i++) {
k_ipad[i] = 0x36;
k_opad[i] = 0x5c;
}
sha256_update(&ctx, k_ipad, SHA256_BLOCK_SIZE);
sha256_update(&ctx, buff, len);
sha256_finish(&ctx, output);
/* Init context for second pass */
sha256_starts(&ctx);
/* start with outer pad */
sha256_update(&ctx, k_opad, SHA256_BLOCK_SIZE);
/* then results of 1st hash */
sha256_update(&ctx, output, RPMB_SZ_MAC);
/* finish up 2nd pass */
sha256_finish(&ctx, output);
}
int mmc_rpmb_get_counter(struct mmc *mmc, unsigned long *pcounter)
{
int ret;
ALLOC_CACHE_ALIGN_BUFFER(struct s_rpmb, rpmb_frame, 1);
/* Fill the request */
memset(rpmb_frame, 0, sizeof(struct s_rpmb));
rpmb_frame->request = cpu_to_be16(RPMB_REQ_WCOUNTER);
if (mmc_rpmb_request(mmc, rpmb_frame, 1, false))
return -1;
/* Read the result */
ret = mmc_rpmb_response(mmc, rpmb_frame, RPMB_RESP_WCOUNTER);
if (ret)
return ret;
*pcounter = be32_to_cpu(rpmb_frame->write_counter);
return 0;
}
int mmc_rpmb_set_key(struct mmc *mmc, void *key)
{
ALLOC_CACHE_ALIGN_BUFFER(struct s_rpmb, rpmb_frame, 1);
/* Fill the request */
memset(rpmb_frame, 0, sizeof(struct s_rpmb));
rpmb_frame->request = cpu_to_be16(RPMB_REQ_KEY);
memcpy(rpmb_frame->mac, key, RPMB_SZ_MAC);
if (mmc_rpmb_request(mmc, rpmb_frame, 1, true))
return -1;
/* read the operation status */
return mmc_rpmb_status(mmc, RPMB_RESP_KEY);
}
int mmc_rpmb_read(struct mmc *mmc, void *addr, unsigned short blk,
unsigned short cnt, unsigned char *key)
{
ALLOC_CACHE_ALIGN_BUFFER(struct s_rpmb, rpmb_frame, 1);
int i;
for (i = 0; i < cnt; i++) {
/* Fill the request */
memset(rpmb_frame, 0, sizeof(struct s_rpmb));
rpmb_frame->address = cpu_to_be16(blk + i);
rpmb_frame->request = cpu_to_be16(RPMB_REQ_READ_DATA);
if (mmc_rpmb_request(mmc, rpmb_frame, 1, false))
break;
/* Read the result */
if (mmc_rpmb_response(mmc, rpmb_frame, RPMB_RESP_READ_DATA))
break;
/* Check the HMAC if key is provided */
if (key) {
unsigned char ret_hmac[RPMB_SZ_MAC];
rpmb_hmac(key, rpmb_frame->data, 284, ret_hmac);
if (memcmp(ret_hmac, rpmb_frame->mac, RPMB_SZ_MAC)) {
printf("MAC error on block #%d\n", i);
break;
}
}
/* Copy data */
memcpy(addr + i * RPMB_SZ_DATA, rpmb_frame->data, RPMB_SZ_DATA);
}
return i;
}
int mmc_rpmb_write(struct mmc *mmc, void *addr, unsigned short blk,
unsigned short cnt, unsigned char *key)
{
ALLOC_CACHE_ALIGN_BUFFER(struct s_rpmb, rpmb_frame, 1);
unsigned long wcount;
int i;
for (i = 0; i < cnt; i++) {
if (mmc_rpmb_get_counter(mmc, &wcount)) {
printf("Cannot read RPMB write counter\n");
break;
}
/* Fill the request */
memset(rpmb_frame, 0, sizeof(struct s_rpmb));
memcpy(rpmb_frame->data, addr + i * RPMB_SZ_DATA, RPMB_SZ_DATA);
rpmb_frame->address = cpu_to_be16(blk + i);
rpmb_frame->block_count = cpu_to_be16(1);
rpmb_frame->write_counter = cpu_to_be32(wcount);
rpmb_frame->request = cpu_to_be16(RPMB_REQ_WRITE_DATA);
/* Computes HMAC */
rpmb_hmac(key, rpmb_frame->data, 284, rpmb_frame->mac);
if (mmc_rpmb_request(mmc, rpmb_frame, 1, true))
break;
/* Get status */
if (mmc_rpmb_status(mmc, RPMB_RESP_WRITE_DATA))
break;
}
return i;
}