tools/sunxi_toc0.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * (C) Copyright 2018 Arm Ltd.
   4  * (C) Copyright 2020-2021 Samuel Holland <samuel@sholland.org>
   5  */
   6
   7 #define OPENSSL_API_COMPAT 0x10101000L
   8
   9 #include <assert.h>
  10 #include <stdint.h>
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <string.h>
  14
  15 #include <openssl/asn1t.h>
  16 #include <openssl/bn.h>
  17 #include <openssl/pem.h>
  18 #include <openssl/rsa.h>
  19
  20 #include <image.h>
  21 #include <sunxi_image.h>
  22
  23 #include "imagetool.h"
  24 #include "mkimage.h"
  25
  26 /*
  27  * NAND requires 8K padding. For other devices, BROM requires only
  28  * 512B padding, but let's use the larger padding to cover everything.
  29  */
  30 #define PAD_SIZE                8192
  31
  32 #define pr_fmt(fmt)             "mkimage (TOC0): %s: " fmt
  33 #define pr_err(fmt, args...)    fprintf(stderr, pr_fmt(fmt), "error", ##args)
  34 #define pr_warn(fmt, args...)   fprintf(stderr, pr_fmt(fmt), "warning", ##args)
  35 #define pr_info(fmt, args...)   fprintf(stderr, pr_fmt(fmt), "info", ##args)
  36
  37 #if defined(LIBRESSL_VERSION_NUMBER) && LIBRESSL_VERSION_NUMBER < 0x3050000fL
  38 #define RSA_get0_n(key) (key)->n
  39 #define RSA_get0_e(key) (key)->e
  40 #define RSA_get0_d(key) (key)->d
  41 #endif
  42
  43 struct __packed toc0_key_item {
  44         __le32  vendor_id;
  45         __le32  key0_n_len;
  46         __le32  key0_e_len;
  47         __le32  key1_n_len;
  48         __le32  key1_e_len;
  49         __le32  sig_len;
  50         uint8_t key0[512];
  51         uint8_t key1[512];
  52         uint8_t reserved[32];
  53         uint8_t sig[256];
  54 };
  55
  56 /*
  57  * This looks somewhat like an X.509 certificate, but it is not valid BER.
  58  *
  59  * Some differences:
  60  *  - Some X.509 certificate fields are missing or rearranged.
  61  *  - Some sequences have the wrong tag.
  62  *  - Zero-length sequences are accepted.
  63  *  - Large strings and integers must be an even number of bytes long.
  64  *  - Positive integers are not zero-extended to maintain their sign.
  65  *
  66  * See https://linux-sunxi.org/TOC0 for more information.
  67  */
  68 struct __packed toc0_small_tag {
  69         uint8_t tag;
  70         uint8_t length;
  71 };
  72
  73 typedef struct toc0_small_tag toc0_small_int;
  74 typedef struct toc0_small_tag toc0_small_oct;
  75 typedef struct toc0_small_tag toc0_small_seq;
  76 typedef struct toc0_small_tag toc0_small_exp;
  77
  78 #define TOC0_SMALL_INT(len) { 0x02, (len) }
  79 #define TOC0_SMALL_SEQ(len) { 0x30, (len) }
  80 #define TOC0_SMALL_EXP(tag, len) { 0xa0 | (tag), len }
  81
  82 struct __packed toc0_large_tag {
  83         uint8_t tag;
  84         uint8_t prefix;
  85         uint8_t length_hi;
  86         uint8_t length_lo;
  87 };
  88
  89 typedef struct toc0_large_tag toc0_large_int;
  90 typedef struct toc0_large_tag toc0_large_bit;
  91 typedef struct toc0_large_tag toc0_large_seq;
  92
  93 #define TOC0_LARGE_INT(len) { 0x02, 0x82, (len) >> 8, (len) & 0xff }
  94 #define TOC0_LARGE_BIT(len) { 0x03, 0x82, (len) >> 8, (len) & 0xff }
  95 #define TOC0_LARGE_SEQ(len) { 0x30, 0x82, (len) >> 8, (len) & 0xff }
  96
  97 struct __packed toc0_cert_item {
  98         toc0_large_seq tag_totalSequence;
  99         struct __packed toc0_totalSequence {
 100                 toc0_large_seq tag_mainSequence;
 101                 struct __packed toc0_mainSequence {
 102                         toc0_small_exp tag_explicit0;
 103                         struct __packed toc0_explicit0 {
 104                                 toc0_small_int tag_version;
 105                                 uint8_t version;
 106                         } explicit0;
 107                         toc0_small_int tag_serialNumber;
 108                         uint8_t serialNumber;
 109                         toc0_small_seq tag_signature;
 110                         toc0_small_seq tag_issuer;
 111                         toc0_small_seq tag_validity;
 112                         toc0_small_seq tag_subject;
 113                         toc0_large_seq tag_subjectPublicKeyInfo;
 114                         struct __packed toc0_subjectPublicKeyInfo {
 115                                 toc0_small_seq tag_algorithm;
 116                                 toc0_large_seq tag_publicKey;
 117                                 struct __packed toc0_publicKey {
 118                                         toc0_large_int tag_n;
 119                                         uint8_t n[256];
 120                                         toc0_small_int tag_e;
 121                                         uint8_t e[3];
 122                                 } publicKey;
 123                         } subjectPublicKeyInfo;
 124                         toc0_small_exp tag_explicit3;
 125                         struct __packed toc0_explicit3 {
 126                                 toc0_small_seq tag_extension;
 127                                 struct __packed toc0_extension {
 128                                         toc0_small_int tag_digest;
 129                                         uint8_t digest[32];
 130                                 } extension;
 131                         } explicit3;
 132                 } mainSequence;
 133                 toc0_large_bit tag_sigSequence;
 134                 struct __packed toc0_sigSequence {
 135                         toc0_small_seq tag_algorithm;
 136                         toc0_large_bit tag_signature;
 137                         uint8_t signature[256];
 138                 } sigSequence;
 139         } totalSequence;
 140 };
 141
 142 #define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
 143
 144 static const struct toc0_cert_item cert_item_template = {
 145         TOC0_LARGE_SEQ(sizeof(struct toc0_totalSequence)),
 146         {
 147                 TOC0_LARGE_SEQ(sizeof(struct toc0_mainSequence)),
 148                 {
 149                         TOC0_SMALL_EXP(0, sizeof(struct toc0_explicit0)),
 150                         {
 151                                 TOC0_SMALL_INT(sizeof_field(struct toc0_explicit0, version)),
 152                                 0,
 153                         },
 154                         TOC0_SMALL_INT(sizeof_field(struct toc0_mainSequence, serialNumber)),
 155                         0,
 156                         TOC0_SMALL_SEQ(0),
 157                         TOC0_SMALL_SEQ(0),
 158                         TOC0_SMALL_SEQ(0),
 159                         TOC0_SMALL_SEQ(0),
 160                         TOC0_LARGE_SEQ(sizeof(struct toc0_subjectPublicKeyInfo)),
 161                         {
 162                                 TOC0_SMALL_SEQ(0),
 163                                 TOC0_LARGE_SEQ(sizeof(struct toc0_publicKey)),
 164                                 {
 165                                         TOC0_LARGE_INT(sizeof_field(struct toc0_publicKey, n)),
 166                                         {},
 167                                         TOC0_SMALL_INT(sizeof_field(struct toc0_publicKey, e)),
 168                                         {},
 169                                 },
 170                         },
 171                         TOC0_SMALL_EXP(3, sizeof(struct toc0_explicit3)),
 172                         {
 173                                 TOC0_SMALL_SEQ(sizeof(struct toc0_extension)),
 174                                 {
 175                                         TOC0_SMALL_INT(sizeof_field(struct toc0_extension, digest)),
 176                                         {},
 177                                 },
 178                         },
 179                 },
 180                 TOC0_LARGE_BIT(sizeof(struct toc0_sigSequence)),
 181                 {
 182                         TOC0_SMALL_SEQ(0),
 183                         TOC0_LARGE_BIT(sizeof_field(struct toc0_sigSequence, signature)),
 184                         {},
 185                 },
 186         },
 187 };
 188
 189 #define TOC0_DEFAULT_NUM_ITEMS          3
 190 #define TOC0_DEFAULT_HEADER_LEN                                           \
 191         ALIGN(                                                            \
 192                 sizeof(struct toc0_main_info)                           + \
 193                 sizeof(struct toc0_item_info) * TOC0_DEFAULT_NUM_ITEMS  + \
 194                 sizeof(struct toc0_cert_item)                           + \
 195                 sizeof(struct toc0_key_item),                             \
 196         32)
 197
 198 static char *fw_key_file   = "fw_key.pem";
 199 static char *key_item_file = "key_item.bin";
 200 static char *root_key_file = "root_key.pem";
 201
 202 /*
 203  * Create a key item in @buf, containing the public keys @root_key and @fw_key,
 204  * and signed by the RSA key @root_key.
 205  */
 206 static int toc0_create_key_item(uint8_t *buf, uint32_t *len,
 207                                 RSA *root_key, RSA *fw_key)
 208 {
 209         struct toc0_key_item *key_item = (void *)buf;
 210         uint8_t digest[SHA256_DIGEST_LENGTH];
 211         int ret = EXIT_FAILURE;
 212         unsigned int sig_len;
 213         int n_len, e_len;
 214
 215         /* Store key 0. */
 216         n_len = BN_bn2bin(RSA_get0_n(root_key), key_item->key0);
 217         e_len = BN_bn2bin(RSA_get0_e(root_key), key_item->key0 + n_len);
 218         if (n_len + e_len > sizeof(key_item->key0)) {
 219                 pr_err("Root key is too big for key item\n");
 220                 goto err;
 221         }
 222         key_item->key0_n_len = cpu_to_le32(n_len);
 223         key_item->key0_e_len = cpu_to_le32(e_len);
 224
 225         /* Store key 1. */
 226         n_len = BN_bn2bin(RSA_get0_n(fw_key), key_item->key1);
 227         e_len = BN_bn2bin(RSA_get0_e(fw_key), key_item->key1 + n_len);
 228         if (n_len + e_len > sizeof(key_item->key1)) {
 229                 pr_err("Firmware key is too big for key item\n");
 230                 goto err;
 231         }
 232         key_item->key1_n_len = cpu_to_le32(n_len);
 233         key_item->key1_e_len = cpu_to_le32(e_len);
 234
 235         /* Sign the key item. */
 236         key_item->sig_len = cpu_to_le32(RSA_size(root_key));
 237         SHA256(buf, key_item->sig - buf, digest);
 238         if (!RSA_sign(NID_sha256, digest, sizeof(digest),
 239                       key_item->sig, &sig_len, root_key)) {
 240                 pr_err("Failed to sign key item\n");
 241                 goto err;
 242         }
 243         if (sig_len != sizeof(key_item->sig)) {
 244                 pr_err("Bad key item signature length\n");
 245                 goto err;
 246         }
 247
 248         *len = sizeof(*key_item);
 249         ret = EXIT_SUCCESS;
 250
 251 err:
 252         return ret;
 253 }
 254
 255 /*
 256  * Verify the key item in @buf, containing two public keys @key0 and @key1,
 257  * and signed by the RSA key @key0. If @root_key is provided, only signatures
 258  * by that key will be accepted. @key1 is returned in @key.
 259  */
 260 static int toc0_verify_key_item(const uint8_t *buf, uint32_t len,
 261                                 RSA *root_key, RSA **fw_key)
 262 {
 263         struct toc0_key_item *key_item = (void *)buf;
 264         uint8_t digest[SHA256_DIGEST_LENGTH];
 265         int ret = EXIT_FAILURE;
 266         int n_len, e_len;
 267         RSA *key0 = NULL;
 268         RSA *key1 = NULL;
 269         BIGNUM *n, *e;
 270
 271         if (len < sizeof(*key_item))
 272                 goto err;
 273
 274         /* Load key 0. */
 275         n_len = le32_to_cpu(key_item->key0_n_len);
 276         e_len = le32_to_cpu(key_item->key0_e_len);
 277         if (n_len + e_len > sizeof(key_item->key0)) {
 278                 pr_err("Bad root key size in key item\n");
 279                 goto err;
 280         }
 281         n = BN_bin2bn(key_item->key0, n_len, NULL);
 282         e = BN_bin2bn(key_item->key0 + n_len, e_len, NULL);
 283         key0 = RSA_new();
 284         if (!key0)
 285                 goto err;
 286         if (!RSA_set0_key(key0, n, e, NULL))
 287                 goto err;
 288
 289         /* If a root key was provided, compare it to key 0. */
 290         if (root_key && (BN_cmp(n, RSA_get0_n(root_key)) ||
 291                          BN_cmp(e, RSA_get0_e(root_key)))) {
 292                 pr_err("Wrong root key in key item\n");
 293                 goto err;
 294         }
 295
 296         /* Verify the key item signature. */
 297         SHA256(buf, key_item->sig - buf, digest);
 298         if (!RSA_verify(NID_sha256, digest, sizeof(digest),
 299                         key_item->sig, le32_to_cpu(key_item->sig_len), key0)) {
 300                 pr_err("Bad key item signature\n");
 301                 goto err;
 302         }
 303
 304         if (fw_key) {
 305                 /* Load key 1. */
 306                 n_len = le32_to_cpu(key_item->key1_n_len);
 307                 e_len = le32_to_cpu(key_item->key1_e_len);
 308                 if (n_len + e_len > sizeof(key_item->key1)) {
 309                         pr_err("Bad firmware key size in key item\n");
 310                         goto err;
 311                 }
 312                 n = BN_bin2bn(key_item->key1, n_len, NULL);
 313                 e = BN_bin2bn(key_item->key1 + n_len, e_len, NULL);
 314                 key1 = RSA_new();
 315                 if (!key1)
 316                         goto err;
 317                 if (!RSA_set0_key(key1, n, e, NULL))
 318                         goto err;
 319
 320                 if (*fw_key) {
 321                         /* If a FW key was provided, compare it to key 1. */
 322                         if (BN_cmp(n, RSA_get0_n(*fw_key)) ||
 323                             BN_cmp(e, RSA_get0_e(*fw_key))) {
 324                                 pr_err("Wrong firmware key in key item\n");
 325                                 goto err;
 326                         }
 327                 } else {
 328                         /* Otherwise, send key1 back to the caller. */
 329                         *fw_key = key1;
 330                         key1 = NULL;
 331                 }
 332         }
 333
 334         ret = EXIT_SUCCESS;
 335
 336 err:
 337         RSA_free(key0);
 338         RSA_free(key1);
 339
 340         return ret;
 341 }
 342
 343 /*
 344  * Create a certificate in @buf, describing the firmware with SHA256 digest
 345  * @digest, and signed by the RSA key @fw_key.
 346  */
 347 static int toc0_create_cert_item(uint8_t *buf, uint32_t *len, RSA *fw_key,
 348                                  uint8_t digest[static SHA256_DIGEST_LENGTH])
 349 {
 350         struct toc0_cert_item *cert_item = (void *)buf;
 351         uint8_t cert_digest[SHA256_DIGEST_LENGTH];
 352         struct toc0_totalSequence *totalSequence;
 353         struct toc0_sigSequence *sigSequence;
 354         struct toc0_extension *extension;
 355         struct toc0_publicKey *publicKey;
 356         int ret = EXIT_FAILURE;
 357         unsigned int sig_len;
 358
 359         memcpy(cert_item, &cert_item_template, sizeof(*cert_item));
 360         *len = sizeof(*cert_item);
 361
 362         /*
 363          * Fill in the public key.
 364          *
 365          * Only 2048-bit RSA keys are supported. Since this uses a fixed-size
 366          * structure, it may fail for non-standard exponents.
 367          */
 368         totalSequence = &cert_item->totalSequence;
 369         publicKey = &totalSequence->mainSequence.subjectPublicKeyInfo.publicKey;
 370         if (BN_bn2binpad(RSA_get0_n(fw_key), publicKey->n, sizeof(publicKey->n)) < 0 ||
 371             BN_bn2binpad(RSA_get0_e(fw_key), publicKey->e, sizeof(publicKey->e)) < 0) {
 372                 pr_err("Firmware key is too big for certificate\n");
 373                 goto err;
 374         }
 375
 376         /* Fill in the firmware digest. */
 377         extension = &totalSequence->mainSequence.explicit3.extension;
 378         memcpy(&extension->digest, digest, SHA256_DIGEST_LENGTH);
 379
 380         /*
 381          * Sign the certificate.
 382          *
 383          * In older SBROM versions (and by default in newer versions),
 384          * the last 4 bytes of the certificate are not signed.
 385          *
 386          * (The buffer passed to SHA256 starts at tag_mainSequence, but
 387          *  the buffer size does not include the length of that tag.)
 388          */
 389         SHA256((uint8_t *)totalSequence, sizeof(struct toc0_mainSequence), cert_digest);
 390         sigSequence = &totalSequence->sigSequence;
 391         if (!RSA_sign(NID_sha256, cert_digest, SHA256_DIGEST_LENGTH,
 392                       sigSequence->signature, &sig_len, fw_key)) {
 393                 pr_err("Failed to sign certificate\n");
 394                 goto err;
 395         }
 396         if (sig_len != sizeof(sigSequence->signature)) {
 397                 pr_err("Bad certificate signature length\n");
 398                 goto err;
 399         }
 400
 401         ret = EXIT_SUCCESS;
 402
 403 err:
 404         return ret;
 405 }
 406
 407 /*
 408  * Verify the certificate in @buf, describing the firmware with SHA256 digest
 409  * @digest, and signed by the RSA key contained within. If @fw_key is provided,
 410  * only that key will be accepted.
 411  *
 412  * This function is only expected to work with images created by mkimage.
 413  */
 414 static int toc0_verify_cert_item(const uint8_t *buf, uint32_t len, RSA *fw_key,
 415                                  uint8_t digest[static SHA256_DIGEST_LENGTH])
 416 {
 417         const struct toc0_cert_item *cert_item = (const void *)buf;
 418         uint8_t cert_digest[SHA256_DIGEST_LENGTH];
 419         const struct toc0_totalSequence *totalSequence;
 420         const struct toc0_sigSequence *sigSequence;
 421         const struct toc0_extension *extension;
 422         const struct toc0_publicKey *publicKey;
 423         int ret = EXIT_FAILURE;
 424         RSA *key = NULL;
 425         BIGNUM *n, *e;
 426
 427         /* Extract the public key from the certificate. */
 428         totalSequence = &cert_item->totalSequence;
 429         publicKey = &totalSequence->mainSequence.subjectPublicKeyInfo.publicKey;
 430         n = BN_bin2bn(publicKey->n, sizeof(publicKey->n), NULL);
 431         e = BN_bin2bn(publicKey->e, sizeof(publicKey->e), NULL);
 432         key = RSA_new();
 433         if (!key)
 434                 goto err;
 435         if (!RSA_set0_key(key, n, e, NULL))
 436                 goto err;
 437
 438         /* If a key was provided, compare it to the embedded key. */
 439         if (fw_key && (BN_cmp(RSA_get0_n(key), RSA_get0_n(fw_key)) ||
 440                        BN_cmp(RSA_get0_e(key), RSA_get0_e(fw_key)))) {
 441                 pr_err("Wrong firmware key in certificate\n");
 442                 goto err;
 443         }
 444
 445         /* If a digest was provided, compare it to the embedded digest. */
 446         extension = &totalSequence->mainSequence.explicit3.extension;
 447         if (digest && memcmp(&extension->digest, digest, SHA256_DIGEST_LENGTH)) {
 448                 pr_err("Wrong firmware digest in certificate\n");
 449                 goto err;
 450         }
 451
 452         /* Verify the certificate's signature. See the comment above. */
 453         SHA256((uint8_t *)totalSequence, sizeof(struct toc0_mainSequence), cert_digest);
 454         sigSequence = &totalSequence->sigSequence;
 455         if (!RSA_verify(NID_sha256, cert_digest, SHA256_DIGEST_LENGTH,
 456                         sigSequence->signature,
 457                         sizeof(sigSequence->signature), key)) {
 458                 pr_err("Bad certificate signature\n");
 459                 goto err;
 460         }
 461
 462         ret = EXIT_SUCCESS;
 463
 464 err:
 465         RSA_free(key);
 466
 467         return ret;
 468 }
 469
 470 /*
 471  * Always create a TOC0 containing 3 items. The extra item will be ignored on
 472  * SoCs which do not support it.
 473  */
 474 static int toc0_create(uint8_t *buf, uint32_t len, RSA *root_key, RSA *fw_key,
 475                        uint8_t *key_item, uint32_t key_item_len,
 476                        uint8_t *fw_item, uint32_t fw_item_len, uint32_t fw_addr)
 477 {
 478         struct toc0_main_info *main_info = (void *)buf;
 479         struct toc0_item_info *item_info = (void *)(main_info + 1);
 480         uint8_t digest[SHA256_DIGEST_LENGTH];
 481         uint32_t *buf32 = (void *)buf;
 482         RSA *orig_fw_key = fw_key;
 483         int ret = EXIT_FAILURE;
 484         uint32_t checksum = 0;
 485         uint32_t item_offset;
 486         uint32_t item_length;
 487         int i;
 488
 489         /* Hash the firmware for inclusion in the certificate. */
 490         SHA256(fw_item, fw_item_len, digest);
 491
 492         /* Create the main TOC0 header, containing three items. */
 493         memcpy(main_info->name, TOC0_MAIN_INFO_NAME, sizeof(main_info->name));
 494         main_info->magic        = cpu_to_le32(TOC0_MAIN_INFO_MAGIC);
 495         main_info->checksum     = cpu_to_le32(BROM_STAMP_VALUE);
 496         main_info->num_items    = cpu_to_le32(TOC0_DEFAULT_NUM_ITEMS);
 497         memcpy(main_info->end, TOC0_MAIN_INFO_END, sizeof(main_info->end));
 498
 499         /* The first item links the ROTPK to the signing key. */
 500         item_offset = sizeof(*main_info) +
 501                       sizeof(*item_info) * TOC0_DEFAULT_NUM_ITEMS;
 502         /* Using an existing key item avoids needing the root private key. */
 503         if (key_item) {
 504                 item_length = sizeof(*key_item);
 505                 if (toc0_verify_key_item(key_item, item_length,
 506                                          root_key, &fw_key))
 507                         goto err;
 508                 memcpy(buf + item_offset, key_item, item_length);
 509         } else if (toc0_create_key_item(buf + item_offset, &item_length,
 510                                         root_key, fw_key)) {
 511                 goto err;
 512         }
 513
 514         item_info->name         = cpu_to_le32(TOC0_ITEM_INFO_NAME_KEY);
 515         item_info->offset       = cpu_to_le32(item_offset);
 516         item_info->length       = cpu_to_le32(item_length);
 517         memcpy(item_info->end, TOC0_ITEM_INFO_END, sizeof(item_info->end));
 518
 519         /* The second item contains a certificate signed by the firmware key. */
 520         item_offset = item_offset + item_length;
 521         if (toc0_create_cert_item(buf + item_offset, &item_length,
 522                                   fw_key, digest))
 523                 goto err;
 524
 525         item_info++;
 526         item_info->name         = cpu_to_le32(TOC0_ITEM_INFO_NAME_CERT);
 527         item_info->offset       = cpu_to_le32(item_offset);
 528         item_info->length       = cpu_to_le32(item_length);
 529         memcpy(item_info->end, TOC0_ITEM_INFO_END, sizeof(item_info->end));
 530
 531         /* The third item contains the actual boot code. */
 532         item_offset = ALIGN(item_offset + item_length, 32);
 533         item_length = fw_item_len;
 534         if (buf + item_offset != fw_item)
 535                 memmove(buf + item_offset, fw_item, item_length);
 536
 537         item_info++;
 538         item_info->name         = cpu_to_le32(TOC0_ITEM_INFO_NAME_FIRMWARE);
 539         item_info->offset       = cpu_to_le32(item_offset);
 540         item_info->length       = cpu_to_le32(item_length);
 541         item_info->load_addr    = cpu_to_le32(fw_addr);
 542         memcpy(item_info->end, TOC0_ITEM_INFO_END, sizeof(item_info->end));
 543
 544         /* Pad to the required block size with 0xff to be flash-friendly. */
 545         item_offset = item_offset + item_length;
 546         item_length = ALIGN(item_offset, PAD_SIZE) - item_offset;
 547         memset(buf + item_offset, 0xff, item_length);
 548
 549         /* Fill in the total padded file length. */
 550         item_offset = item_offset + item_length;
 551         main_info->length = cpu_to_le32(item_offset);
 552
 553         /* Verify enough space was provided when creating the image. */
 554         assert(len >= item_offset);
 555
 556         /* Calculate the checksum. Yes, it's that simple. */
 557         for (i = 0; i < item_offset / 4; ++i)
 558                 checksum += le32_to_cpu(buf32[i]);
 559         main_info->checksum = cpu_to_le32(checksum);
 560
 561         ret = EXIT_SUCCESS;
 562
 563 err:
 564         if (fw_key != orig_fw_key)
 565                 RSA_free(fw_key);
 566
 567         return ret;
 568 }
 569
 570 static const struct toc0_item_info *
 571 toc0_find_item(const struct toc0_main_info *main_info, uint32_t name,
 572                uint32_t *offset, uint32_t *length)
 573 {
 574         const struct toc0_item_info *item_info = (void *)(main_info + 1);
 575         uint32_t item_offset, item_length;
 576         uint32_t num_items, main_length;
 577         int i;
 578
 579         num_items   = le32_to_cpu(main_info->num_items);
 580         main_length = le32_to_cpu(main_info->length);
 581
 582         for (i = 0; i < num_items; ++i, ++item_info) {
 583                 if (le32_to_cpu(item_info->name) != name)
 584                         continue;
 585
 586                 item_offset = le32_to_cpu(item_info->offset);
 587                 item_length = le32_to_cpu(item_info->length);
 588
 589                 if (item_offset > main_length ||
 590                     item_length > main_length - item_offset)
 591                         continue;
 592
 593                 *offset = item_offset;
 594                 *length = item_length;
 595
 596                 return item_info;
 597         }
 598
 599         return NULL;
 600 }
 601
 602 static int toc0_verify(const uint8_t *buf, uint32_t len, RSA *root_key)
 603 {
 604         const struct toc0_main_info *main_info = (void *)buf;
 605         const struct toc0_item_info *item_info;
 606         uint8_t digest[SHA256_DIGEST_LENGTH];
 607         uint32_t main_length = le32_to_cpu(main_info->length);
 608         uint32_t checksum = BROM_STAMP_VALUE;
 609         uint32_t *buf32 = (void *)buf;
 610         uint32_t length, offset;
 611         int ret = EXIT_FAILURE;
 612         RSA *fw_key = NULL;
 613         int i;
 614
 615         if (len < main_length)
 616                 goto err;
 617
 618         /* Verify the main header. */
 619         if (memcmp(main_info->name, TOC0_MAIN_INFO_NAME, sizeof(main_info->name)))
 620                 goto err;
 621         if (le32_to_cpu(main_info->magic) != TOC0_MAIN_INFO_MAGIC)
 622                 goto err;
 623         /* Verify the checksum without modifying the buffer. */
 624         for (i = 0; i < main_length / 4; ++i)
 625                 checksum += le32_to_cpu(buf32[i]);
 626         if (checksum != 2 * le32_to_cpu(main_info->checksum))
 627                 goto err;
 628         /* The length must be at least 512 byte aligned. */
 629         if (main_length % 512)
 630                 goto err;
 631         if (memcmp(main_info->end, TOC0_MAIN_INFO_END, sizeof(main_info->end)))
 632                 goto err;
 633
 634         /* Verify the key item if present (it is optional). */
 635         item_info = toc0_find_item(main_info, TOC0_ITEM_INFO_NAME_KEY,
 636                                    &offset, &length);
 637         if (!item_info)
 638                 fw_key = root_key;
 639         else if (toc0_verify_key_item(buf + offset, length, root_key, &fw_key))
 640                 goto err;
 641
 642         /* Hash the firmware to compare with the certificate. */
 643         item_info = toc0_find_item(main_info, TOC0_ITEM_INFO_NAME_FIRMWARE,
 644                                    &offset, &length);
 645         if (!item_info) {
 646                 pr_err("Missing firmware item\n");
 647                 goto err;
 648         }
 649         SHA256(buf + offset, length, digest);
 650
 651         /* Verify the certificate item. */
 652         item_info = toc0_find_item(main_info, TOC0_ITEM_INFO_NAME_CERT,
 653                                    &offset, &length);
 654         if (!item_info) {
 655                 pr_err("Missing certificate item\n");
 656                 goto err;
 657         }
 658         if (toc0_verify_cert_item(buf + offset, length, fw_key, digest))
 659                 goto err;
 660
 661         ret = EXIT_SUCCESS;
 662
 663 err:
 664         if (fw_key != root_key)
 665                 RSA_free(fw_key);
 666
 667         return ret;
 668 }
 669
 670 static int toc0_check_params(struct image_tool_params *params)
 671 {
 672         if (!params->dflag)
 673                 return -EINVAL;
 674
 675         /*
 676          * If a key directory was provided, look for key files there.
 677          * Otherwise, look for them in the current directory. The key files are
 678          * the "quoted" terms in the description below.
 679          *
 680          * A summary of the chain of trust on most SoCs:
 681          *  1) eFuse contains a SHA256 digest of the public "root key".
 682          *  2) Private "root key" signs the certificate item (generated here).
 683          *  3) Certificate item contains a SHA256 digest of the firmware item.
 684          *
 685          * A summary of the chain of trust on the H6 (by default; a bit in the
 686          * BROM_CONFIG eFuse makes it work like above):
 687          *  1) eFuse contains a SHA256 digest of the public "root key".
 688          *  2) Private "root key" signs the "key item" (generated here).
 689          *  3) "Key item" contains the public "root key" and public "fw key".
 690          *  4) Private "fw key" signs the certificate item (generated here).
 691          *  5) Certificate item contains a SHA256 digest of the firmware item.
 692          *
 693          * This means there are three valid ways to generate a TOC0:
 694          *  1) Provide the private "root key" only. This works everywhere.
 695          *     For H6, the "root key" will also be used as the "fw key".
 696          *  2) FOR H6 ONLY: Provide the private "root key" and a separate
 697          *     private "fw key".
 698          *  3) FOR H6 ONLY: Provide the private "fw key" and a pre-existing
 699          *     "key item" containing the corresponding  public "fw key".
 700          *     In this case, the private "root key" can be kept offline. The
 701          *     "key item" can be extracted from a TOC0 image generated using
 702          *     method #2 above.
 703          *
 704          *  Note that until the ROTPK_HASH eFuse is programmed, any "root key"
 705          *  will be accepted by the BROM.
 706          */
 707         if (params->keydir) {
 708                 if (asprintf(&fw_key_file, "%s/%s", params->keydir, fw_key_file) < 0)
 709                         return -ENOMEM;
 710                 if (asprintf(&key_item_file, "%s/%s", params->keydir, key_item_file) < 0)
 711                         return -ENOMEM;
 712                 if (asprintf(&root_key_file, "%s/%s", params->keydir, root_key_file) < 0)
 713                         return -ENOMEM;
 714         }
 715
 716         return 0;
 717 }
 718
 719 static int toc0_verify_header(unsigned char *buf, int image_size,
 720                               struct image_tool_params *params)
 721 {
 722         int ret = EXIT_FAILURE;
 723         RSA *root_key = NULL;
 724         FILE *fp;
 725
 726         /* A root public key is optional. */
 727         fp = fopen(root_key_file, "rb");
 728         if (fp) {
 729                 pr_info("Verifying image with existing root key\n");
 730                 root_key = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 731                 if (!root_key)
 732                         root_key = PEM_read_RSAPublicKey(fp, NULL, NULL, NULL);
 733                 fclose(fp);
 734                 if (!root_key) {
 735                         pr_err("Failed to read public key from '%s'\n",
 736                                root_key_file);
 737                         goto err;
 738                 }
 739         }
 740
 741         ret = toc0_verify(buf, image_size, root_key);
 742
 743 err:
 744         RSA_free(root_key);
 745
 746         return ret;
 747 }
 748
 749 static const char *toc0_item_name(uint32_t name)
 750 {
 751         if (name == TOC0_ITEM_INFO_NAME_CERT)
 752                 return "Certificate";
 753         if (name == TOC0_ITEM_INFO_NAME_FIRMWARE)
 754                 return "Firmware";
 755         if (name == TOC0_ITEM_INFO_NAME_KEY)
 756                 return "Key";
 757         return "(unknown)";
 758 }
 759
 760 static void toc0_print_header(const void *buf)
 761 {
 762         const struct toc0_main_info *main_info = buf;
 763         const struct toc0_item_info *item_info = (void *)(main_info + 1);
 764         uint32_t head_length, main_length, num_items;
 765         uint32_t item_offset, item_length, item_name;
 766         int load_addr = -1;
 767         int i;
 768
 769         num_items   = le32_to_cpu(main_info->num_items);
 770         head_length = sizeof(*main_info) + num_items * sizeof(*item_info);
 771         main_length = le32_to_cpu(main_info->length);
 772
 773         printf("Allwinner TOC0 Image\n"
 774                "Size: %d bytes\n"
 775                "Contents: %d items\n"
 776                " 00000000:%08x Headers\n",
 777                main_length, num_items, head_length);
 778
 779         for (i = 0; i < num_items; ++i, ++item_info) {
 780                 item_offset = le32_to_cpu(item_info->offset);
 781                 item_length = le32_to_cpu(item_info->length);
 782                 item_name   = le32_to_cpu(item_info->name);
 783
 784                 if (item_name == TOC0_ITEM_INFO_NAME_FIRMWARE)
 785                         load_addr = le32_to_cpu(item_info->load_addr);
 786
 787                 printf(" %08x:%08x %s\n",
 788                        item_offset, item_length,
 789                        toc0_item_name(item_name));
 790         }
 791
 792         if (num_items && item_offset + item_length < main_length) {
 793                 item_offset = item_offset + item_length;
 794                 item_length = main_length - item_offset;
 795
 796                 printf(" %08x:%08x Padding\n",
 797                        item_offset, item_length);
 798         }
 799
 800         if (load_addr != -1)
 801                 printf("Load address: 0x%08x\n", load_addr);
 802 }
 803
 804 static void toc0_set_header(void *buf, struct stat *sbuf, int ifd,
 805                             struct image_tool_params *params)
 806 {
 807         uint32_t key_item_len = 0;
 808         uint8_t *key_item = NULL;
 809         int ret = EXIT_FAILURE;
 810         RSA *root_key = NULL;
 811         RSA *fw_key = NULL;
 812         FILE *fp;
 813
 814         /* Either a key item or the root private key is required. */
 815         fp = fopen(key_item_file, "rb");
 816         if (fp) {
 817                 pr_info("Creating image using existing key item\n");
 818                 key_item_len = sizeof(struct toc0_key_item);
 819                 key_item = OPENSSL_malloc(key_item_len);
 820                 if (!key_item || fread(key_item, key_item_len, 1, fp) != 1) {
 821                         pr_err("Failed to read key item from '%s'\n",
 822                                root_key_file);
 823                         goto err;
 824                 }
 825                 fclose(fp);
 826                 fp = NULL;
 827         }
 828
 829         fp = fopen(root_key_file, "rb");
 830         if (fp) {
 831                 root_key = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 832                 if (!root_key)
 833                         root_key = PEM_read_RSAPublicKey(fp, NULL, NULL, NULL);
 834                 fclose(fp);
 835                 fp = NULL;
 836         }
 837
 838         /* When using an existing key item, the root key is optional. */
 839         if (!key_item && (!root_key || !RSA_get0_d(root_key))) {
 840                 pr_err("Failed to read private key from '%s'\n",
 841                        root_key_file);
 842                 pr_info("Try 'openssl genrsa -out root_key.pem'\n");
 843                 goto err;
 844         }
 845
 846         /* The certificate/firmware private key is always required. */
 847         fp = fopen(fw_key_file, "rb");
 848         if (fp) {
 849                 fw_key = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 850                 fclose(fp);
 851                 fp = NULL;
 852         }
 853         if (!fw_key) {
 854                 /* If the root key is a private key, it can be used instead. */
 855                 if (root_key && RSA_get0_d(root_key)) {
 856                         pr_info("Using root key as firmware key\n");
 857                         fw_key = root_key;
 858                 } else {
 859                         pr_err("Failed to read private key from '%s'\n",
 860                                fw_key_file);
 861                         goto err;
 862                 }
 863         }
 864
 865         /* Warn about potential compatibility issues. */
 866         if (key_item || fw_key != root_key)
 867                 pr_warn("Only H6 supports separate root and firmware keys\n");
 868
 869         ret = toc0_create(buf, params->file_size, root_key, fw_key,
 870                           key_item, key_item_len,
 871                           buf + TOC0_DEFAULT_HEADER_LEN,
 872                           params->orig_file_size, params->addr);
 873
 874 err:
 875         OPENSSL_free(key_item);
 876         OPENSSL_free(root_key);
 877         if (fw_key != root_key)
 878                 OPENSSL_free(fw_key);
 879         if (fp)
 880                 fclose(fp);
 881
 882         if (ret != EXIT_SUCCESS)
 883                 exit(ret);
 884 }
 885
 886 static int toc0_check_image_type(uint8_t type)
 887 {
 888         return type == IH_TYPE_SUNXI_TOC0 ? 0 : 1;
 889 }
 890
 891 static int toc0_vrec_header(struct image_tool_params *params,
 892                             struct image_type_params *tparams)
 893 {
 894         tparams->hdr = calloc(tparams->header_size, 1);
 895
 896         /* Save off the unpadded data size for SHA256 calculation. */
 897         params->orig_file_size = params->file_size - TOC0_DEFAULT_HEADER_LEN;
 898
 899         /* Return padding to 8K blocks. */
 900         return ALIGN(params->file_size, PAD_SIZE) - params->file_size;
 901 }
 902
 903 U_BOOT_IMAGE_TYPE(
 904         sunxi_toc0,
 905         "Allwinner TOC0 Boot Image support",
 906         TOC0_DEFAULT_HEADER_LEN,
 907         NULL,
 908         toc0_check_params,
 909         toc0_verify_header,
 910         toc0_print_header,
 911         toc0_set_header,
 912         NULL,
 913         toc0_check_image_type,
 914         NULL,
 915         toc0_vrec_header
 916 );