1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright 2014, Staubli Faverges
4 * Pierre Aubert
5 *
6 * eMMC- Replay Protected Memory Block
7 * According to JEDEC Standard No. 84-A441
8 */
9
10 #include <config.h>
11 #include <common.h>
12 #include <memalign.h>
13 #include <mmc.h>
14 #include <u-boot/sha256.h>
15 #include "mmc_private.h"
16
17 /* Request codes */
18 #define RPMB_REQ_KEY 1
19 #define RPMB_REQ_WCOUNTER 2
20 #define RPMB_REQ_WRITE_DATA 3
21 #define RPMB_REQ_READ_DATA 4
22 #define RPMB_REQ_STATUS 5
23
24 /* Response code */
25 #define RPMB_RESP_KEY 0x0100
26 #define RPMB_RESP_WCOUNTER 0x0200
27 #define RPMB_RESP_WRITE_DATA 0x0300
28 #define RPMB_RESP_READ_DATA 0x0400
29
30 /* Error codes */
31 #define RPMB_OK 0
32 #define RPMB_ERR_GENERAL 1
33 #define RPMB_ERR_AUTH 2
34 #define RPMB_ERR_COUNTER 3
35 #define RPMB_ERR_ADDRESS 4
36 #define RPMB_ERR_WRITE 5
37 #define RPMB_ERR_READ 6
38 #define RPMB_ERR_KEY 7
39 #define RPMB_ERR_CNT_EXPIRED 0x80
40 #define RPMB_ERR_MSK 0x7
41
42 /* Sizes of RPMB data frame */
43 #define RPMB_SZ_STUFF 196
44 #define RPMB_SZ_MAC 32
45 #define RPMB_SZ_DATA 256
46 #define RPMB_SZ_NONCE 16
47
48 #define SHA256_BLOCK_SIZE 64
49
50 /* Error messages */
51 static const char * const rpmb_err_msg[] = {
52 "",
53 "General failure",
54 "Authentication failure",
55 "Counter failure",
56 "Address failure",
57 "Write failure",
58 "Read failure",
59 "Authentication key not yet programmed",
60 };
61
62
63 /* Structure of RPMB data frame. */
64 struct s_rpmb {
65 unsigned char stuff[RPMB_SZ_STUFF];
66 unsigned char mac[RPMB_SZ_MAC];
67 unsigned char data[RPMB_SZ_DATA];
68 unsigned char nonce[RPMB_SZ_NONCE];
69 unsigned int write_counter;
70 unsigned short address;
71 unsigned short block_count;
72 unsigned short result;
73 unsigned short request;
74 };
75
mmc_set_blockcount(struct mmc * mmc,unsigned int blockcount,bool is_rel_write)76 static int mmc_set_blockcount(struct mmc *mmc, unsigned int blockcount,
77 bool is_rel_write)
78 {
79 struct mmc_cmd cmd = {0};
80
81 cmd.cmdidx = MMC_CMD_SET_BLOCK_COUNT;
82 cmd.cmdarg = blockcount & 0x0000FFFF;
83 if (is_rel_write)
84 cmd.cmdarg |= 1 << 31;
85 cmd.resp_type = MMC_RSP_R1;
86
87 return mmc_send_cmd(mmc, &cmd, NULL);
88 }
mmc_rpmb_request(struct mmc * mmc,const struct s_rpmb * s,unsigned int count,bool is_rel_write)89 static int mmc_rpmb_request(struct mmc *mmc, const struct s_rpmb *s,
90 unsigned int count, bool is_rel_write)
91 {
92 struct mmc_cmd cmd = {0};
93 struct mmc_data data;
94 int ret;
95
96 ret = mmc_set_blockcount(mmc, count, is_rel_write);
97 if (ret) {
98 #ifdef CONFIG_MMC_RPMB_TRACE
99 printf("%s:mmc_set_blockcount-> %d\n", __func__, ret);
100 #endif
101 return 1;
102 }
103
104 cmd.cmdidx = MMC_CMD_WRITE_MULTIPLE_BLOCK;
105 cmd.cmdarg = 0;
106 cmd.resp_type = MMC_RSP_R1b;
107
108 data.src = (const char *)s;
109 data.blocks = 1;
110 data.blocksize = MMC_MAX_BLOCK_LEN;
111 data.flags = MMC_DATA_WRITE;
112
113 ret = mmc_send_cmd(mmc, &cmd, &data);
114 if (ret) {
115 #ifdef CONFIG_MMC_RPMB_TRACE
116 printf("%s:mmc_send_cmd-> %d\n", __func__, ret);
117 #endif
118 return 1;
119 }
120 return 0;
121 }
mmc_rpmb_response(struct mmc * mmc,struct s_rpmb * s,unsigned short expected)122 static int mmc_rpmb_response(struct mmc *mmc, struct s_rpmb *s,
123 unsigned short expected)
124 {
125 struct mmc_cmd cmd = {0};
126 struct mmc_data data;
127 int ret;
128
129 ret = mmc_set_blockcount(mmc, 1, false);
130 if (ret) {
131 #ifdef CONFIG_MMC_RPMB_TRACE
132 printf("%s:mmc_set_blockcount-> %d\n", __func__, ret);
133 #endif
134 return -1;
135 }
136 cmd.cmdidx = MMC_CMD_READ_MULTIPLE_BLOCK;
137 cmd.cmdarg = 0;
138 cmd.resp_type = MMC_RSP_R1;
139
140 data.dest = (char *)s;
141 data.blocks = 1;
142 data.blocksize = MMC_MAX_BLOCK_LEN;
143 data.flags = MMC_DATA_READ;
144
145 ret = mmc_send_cmd(mmc, &cmd, &data);
146 if (ret) {
147 #ifdef CONFIG_MMC_RPMB_TRACE
148 printf("%s:mmc_send_cmd-> %d\n", __func__, ret);
149 #endif
150 return -1;
151 }
152 /* Check the response and the status */
153 if (be16_to_cpu(s->request) != expected) {
154 #ifdef CONFIG_MMC_RPMB_TRACE
155 printf("%s:response= %x\n", __func__,
156 be16_to_cpu(s->request));
157 #endif
158 return -1;
159 }
160 ret = be16_to_cpu(s->result);
161 if (ret) {
162 printf("%s %s\n", rpmb_err_msg[ret & RPMB_ERR_MSK],
163 (ret & RPMB_ERR_CNT_EXPIRED) ?
164 "Write counter has expired" : "");
165 }
166
167 /* Return the status of the command */
168 return ret;
169 }
mmc_rpmb_status(struct mmc * mmc,unsigned short expected)170 static int mmc_rpmb_status(struct mmc *mmc, unsigned short expected)
171 {
172 ALLOC_CACHE_ALIGN_BUFFER(struct s_rpmb, rpmb_frame, 1);
173
174 memset(rpmb_frame, 0, sizeof(struct s_rpmb));
175 rpmb_frame->request = cpu_to_be16(RPMB_REQ_STATUS);
176 if (mmc_rpmb_request(mmc, rpmb_frame, 1, false))
177 return -1;
178
179 /* Read the result */
180 return mmc_rpmb_response(mmc, rpmb_frame, expected);
181 }
rpmb_hmac(unsigned char * key,unsigned char * buff,int len,unsigned char * output)182 static void rpmb_hmac(unsigned char *key, unsigned char *buff, int len,
183 unsigned char *output)
184 {
185 sha256_context ctx;
186 int i;
187 unsigned char k_ipad[SHA256_BLOCK_SIZE];
188 unsigned char k_opad[SHA256_BLOCK_SIZE];
189
190 sha256_starts(&ctx);
191
192 /* According to RFC 4634, the HMAC transform looks like:
193 SHA(K XOR opad, SHA(K XOR ipad, text))
194
195 where K is an n byte key.
196 ipad is the byte 0x36 repeated blocksize times
197 opad is the byte 0x5c repeated blocksize times
198 and text is the data being protected.
199 */
200
201 for (i = 0; i < RPMB_SZ_MAC; i++) {
202 k_ipad[i] = key[i] ^ 0x36;
203 k_opad[i] = key[i] ^ 0x5c;
204 }
205 /* remaining pad bytes are '\0' XOR'd with ipad and opad values */
206 for ( ; i < SHA256_BLOCK_SIZE; i++) {
207 k_ipad[i] = 0x36;
208 k_opad[i] = 0x5c;
209 }
210 sha256_update(&ctx, k_ipad, SHA256_BLOCK_SIZE);
211 sha256_update(&ctx, buff, len);
212 sha256_finish(&ctx, output);
213
214 /* Init context for second pass */
215 sha256_starts(&ctx);
216
217 /* start with outer pad */
218 sha256_update(&ctx, k_opad, SHA256_BLOCK_SIZE);
219
220 /* then results of 1st hash */
221 sha256_update(&ctx, output, RPMB_SZ_MAC);
222
223 /* finish up 2nd pass */
224 sha256_finish(&ctx, output);
225 }
mmc_rpmb_get_counter(struct mmc * mmc,unsigned long * pcounter)226 int mmc_rpmb_get_counter(struct mmc *mmc, unsigned long *pcounter)
227 {
228 int ret;
229 ALLOC_CACHE_ALIGN_BUFFER(struct s_rpmb, rpmb_frame, 1);
230
231 /* Fill the request */
232 memset(rpmb_frame, 0, sizeof(struct s_rpmb));
233 rpmb_frame->request = cpu_to_be16(RPMB_REQ_WCOUNTER);
234 if (mmc_rpmb_request(mmc, rpmb_frame, 1, false))
235 return -1;
236
237 /* Read the result */
238 ret = mmc_rpmb_response(mmc, rpmb_frame, RPMB_RESP_WCOUNTER);
239 if (ret)
240 return ret;
241
242 *pcounter = be32_to_cpu(rpmb_frame->write_counter);
243 return 0;
244 }
mmc_rpmb_set_key(struct mmc * mmc,void * key)245 int mmc_rpmb_set_key(struct mmc *mmc, void *key)
246 {
247 ALLOC_CACHE_ALIGN_BUFFER(struct s_rpmb, rpmb_frame, 1);
248 /* Fill the request */
249 memset(rpmb_frame, 0, sizeof(struct s_rpmb));
250 rpmb_frame->request = cpu_to_be16(RPMB_REQ_KEY);
251 memcpy(rpmb_frame->mac, key, RPMB_SZ_MAC);
252
253 if (mmc_rpmb_request(mmc, rpmb_frame, 1, true))
254 return -1;
255
256 /* read the operation status */
257 return mmc_rpmb_status(mmc, RPMB_RESP_KEY);
258 }
mmc_rpmb_read(struct mmc * mmc,void * addr,unsigned short blk,unsigned short cnt,unsigned char * key)259 int mmc_rpmb_read(struct mmc *mmc, void *addr, unsigned short blk,
260 unsigned short cnt, unsigned char *key)
261 {
262 ALLOC_CACHE_ALIGN_BUFFER(struct s_rpmb, rpmb_frame, 1);
263 int i;
264
265 for (i = 0; i < cnt; i++) {
266 /* Fill the request */
267 memset(rpmb_frame, 0, sizeof(struct s_rpmb));
268 rpmb_frame->address = cpu_to_be16(blk + i);
269 rpmb_frame->request = cpu_to_be16(RPMB_REQ_READ_DATA);
270 if (mmc_rpmb_request(mmc, rpmb_frame, 1, false))
271 break;
272
273 /* Read the result */
274 if (mmc_rpmb_response(mmc, rpmb_frame, RPMB_RESP_READ_DATA))
275 break;
276
277 /* Check the HMAC if key is provided */
278 if (key) {
279 unsigned char ret_hmac[RPMB_SZ_MAC];
280
281 rpmb_hmac(key, rpmb_frame->data, 284, ret_hmac);
282 if (memcmp(ret_hmac, rpmb_frame->mac, RPMB_SZ_MAC)) {
283 printf("MAC error on block #%d\n", i);
284 break;
285 }
286 }
287 /* Copy data */
288 memcpy(addr + i * RPMB_SZ_DATA, rpmb_frame->data, RPMB_SZ_DATA);
289 }
290 return i;
291 }
mmc_rpmb_write(struct mmc * mmc,void * addr,unsigned short blk,unsigned short cnt,unsigned char * key)292 int mmc_rpmb_write(struct mmc *mmc, void *addr, unsigned short blk,
293 unsigned short cnt, unsigned char *key)
294 {
295 ALLOC_CACHE_ALIGN_BUFFER(struct s_rpmb, rpmb_frame, 1);
296 unsigned long wcount;
297 int i;
298
299 for (i = 0; i < cnt; i++) {
300 if (mmc_rpmb_get_counter(mmc, &wcount)) {
301 printf("Cannot read RPMB write counter\n");
302 break;
303 }
304
305 /* Fill the request */
306 memset(rpmb_frame, 0, sizeof(struct s_rpmb));
307 memcpy(rpmb_frame->data, addr + i * RPMB_SZ_DATA, RPMB_SZ_DATA);
308 rpmb_frame->address = cpu_to_be16(blk + i);
309 rpmb_frame->block_count = cpu_to_be16(1);
310 rpmb_frame->write_counter = cpu_to_be32(wcount);
311 rpmb_frame->request = cpu_to_be16(RPMB_REQ_WRITE_DATA);
312 /* Computes HMAC */
313 rpmb_hmac(key, rpmb_frame->data, 284, rpmb_frame->mac);
314
315 if (mmc_rpmb_request(mmc, rpmb_frame, 1, true))
316 break;
317
318 /* Get status */
319 if (mmc_rpmb_status(mmc, RPMB_RESP_WRITE_DATA))
320 break;
321 }
322 return i;
323 }
324