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