diff options
Diffstat (limited to 'bdb/bdb.c')
| -rw-r--r-- | bdb/bdb.c | 398 |
1 files changed, 0 insertions, 398 deletions
diff --git a/bdb/bdb.c b/bdb/bdb.c deleted file mode 100644 index d3327a51..00000000 --- a/bdb/bdb.c +++ /dev/null @@ -1,398 +0,0 @@ -/* Copyright (c) 2015 The Chromium OS Authors. All rights reserved. - * Use of this source code is governed by a BSD-style license that can be - * found in the LICENSE file. - * - * Boot descriptor block firmware functions - */ - -#include <string.h> -#include "bdb.h" - -/*****************************************************************************/ - -/** - * Check if string contains a null terminator. - * - * Bytes after the null terminator do not need to be null. - * - * @param s String to check - * @param size Size of string buffer in characters - * @return 1 if string has a null terminator, 0 if not - */ -int string_has_null(const char *s, size_t size) -{ - for (; size; size--) { - if (*s++ == 0) - return 1; - } - return 0; -} - -int bdb_check_header(const struct bdb_header *p, size_t size) -{ - if (size < sizeof(*p) || size < p->struct_size) - return BDB_ERROR_BUF_SIZE; - - if (p->struct_magic != BDB_HEADER_MAGIC) - return BDB_ERROR_STRUCT_MAGIC; - - if (p->struct_major_version != BDB_HEADER_VERSION_MAJOR) - return BDB_ERROR_STRUCT_VERSION; - - /* Note that minor version doesn't matter yet */ - - if (p->struct_size < sizeof(*p)) - return BDB_ERROR_STRUCT_SIZE; - - if (p->oem_area_0_size & 3) - return BDB_ERROR_OEM_AREA_SIZE; /* Not 32-bit aligned */ - - /* - * Make sure the BDB is at least big enough for us. At this point, all - * the caller may have loaded is this header We'll check if there's - * space for everything else after we load it. - */ - if (p->bdb_size < sizeof(*p)) - return BDB_ERROR_BDB_SIZE; - - /* - * The rest of the fields don't matter yet; we'll check them when we - * check the BDB itself. - */ - return BDB_SUCCESS; -} - -int bdb_check_key(const struct bdb_key *p, size_t size) -{ - size_t expect_key_size = 0; - - if (size < sizeof(*p) || size < p->struct_size) - return BDB_ERROR_BUF_SIZE; - - if (p->struct_magic != BDB_KEY_MAGIC) - return BDB_ERROR_STRUCT_MAGIC; - - if (p->struct_major_version != BDB_KEY_VERSION_MAJOR) - return BDB_ERROR_STRUCT_VERSION; - - /* Note that minor version doesn't matter yet */ - - if (!string_has_null(p->description, sizeof(p->description))) - return BDB_ERROR_DESCRIPTION; - - /* We currently only support SHA-256 */ - if (p->hash_alg != BDB_HASH_ALG_SHA256) - return BDB_ERROR_HASH_ALG; - - /* Make sure signature algorithm and size are correct */ - switch (p->sig_alg) { - case BDB_SIG_ALG_RSA4096: - expect_key_size = BDB_RSA4096_KEY_DATA_SIZE; - break; - case BDB_SIG_ALG_ECSDSA521: - expect_key_size = BDB_ECDSA521_KEY_DATA_SIZE; - break; - case BDB_SIG_ALG_RSA3072B: - expect_key_size = BDB_RSA3072B_KEY_DATA_SIZE; - break; - default: - return BDB_ERROR_SIG_ALG; - } - - if (p->struct_size < sizeof(*p) + expect_key_size) - return BDB_ERROR_STRUCT_SIZE; - - return BDB_SUCCESS; -} - -int bdb_check_sig(const struct bdb_sig *p, size_t size) -{ - size_t expect_sig_size = 0; - - if (size < sizeof(*p) || size < p->struct_size) - return BDB_ERROR_BUF_SIZE; - - if (p->struct_magic != BDB_SIG_MAGIC) - return BDB_ERROR_STRUCT_MAGIC; - - if (p->struct_major_version != BDB_SIG_VERSION_MAJOR) - return BDB_ERROR_STRUCT_VERSION; - - /* Note that minor version doesn't matter yet */ - - if (!string_has_null(p->description, sizeof(p->description))) - return BDB_ERROR_DESCRIPTION; - - /* We currently only support SHA-256 */ - if (p->hash_alg != BDB_HASH_ALG_SHA256) - return BDB_ERROR_HASH_ALG; - - /* Make sure signature algorithm and size are correct */ - switch (p->sig_alg) { - case BDB_SIG_ALG_RSA4096: - expect_sig_size = BDB_RSA4096_SIG_SIZE; - break; - case BDB_SIG_ALG_ECSDSA521: - expect_sig_size = BDB_ECDSA521_SIG_SIZE; - break; - case BDB_SIG_ALG_RSA3072B: - expect_sig_size = BDB_RSA3072B_SIG_SIZE; - break; - default: - return BDB_ERROR_SIG_ALG; - } - - if (p->struct_size < sizeof(*p) + expect_sig_size) - return BDB_ERROR_STRUCT_SIZE; - - return BDB_SUCCESS; -} - -int bdb_check_data(const struct bdb_data *p, size_t size) -{ - size_t need_size; - - if (size < sizeof(*p) || size < p->signed_size) - return BDB_ERROR_BUF_SIZE; - - if (p->struct_magic != BDB_DATA_MAGIC) - return BDB_ERROR_STRUCT_MAGIC; - - if (p->struct_major_version != BDB_DATA_VERSION_MAJOR) - return BDB_ERROR_STRUCT_VERSION; - - /* Note that minor version doesn't matter yet */ - - if (!string_has_null(p->description, sizeof(p->description))) - return BDB_ERROR_DESCRIPTION; - - if (p->struct_size < sizeof(*p)) - return BDB_ERROR_STRUCT_SIZE; - - if (p->hash_entry_size < sizeof(struct bdb_hash)) - return BDB_ERROR_HASH_ENTRY_SIZE; - - /* Calculate expected size */ - need_size = p->struct_size + p->num_hashes * p->hash_entry_size; - - /* Make sure OEM area size doesn't cause wraparound */ - if (need_size + p->oem_area_1_size < need_size) - return BDB_ERROR_OEM_AREA_SIZE; - if (p->oem_area_1_size & 3) - return BDB_ERROR_OEM_AREA_SIZE; /* Not 32-bit aligned */ - need_size += p->oem_area_1_size; - - if (p->signed_size < need_size) - return BDB_ERROR_SIGNED_SIZE; - - return BDB_SUCCESS; -} - -/*****************************************************************************/ - -const struct bdb_header *bdb_get_header(const void *buf) -{ - return buf; -} - -const struct bdb_key *bdb_get_bdbkey(const void *buf) -{ - const struct bdb_header *h = bdb_get_header(buf); - const uint8_t *b8 = buf; - - /* BDB key follows header */ - return (const struct bdb_key *)(b8 + h->struct_size); -} - -const void *bdb_get_oem_area_0(const void *buf) -{ - const struct bdb_key *k = bdb_get_bdbkey(buf); - const uint8_t *b8 = (const uint8_t *)k; - - /* OEM area 0 follows BDB key */ - return b8 + k->struct_size; -} - -const struct bdb_key *bdb_get_subkey(const void *buf) -{ - const struct bdb_header *h = bdb_get_header(buf); - const uint8_t *b8 = bdb_get_oem_area_0(buf); - - /* Subkey follows OEM area 0 */ - return (const struct bdb_key *)(b8 + h->oem_area_0_size); -} - -const struct bdb_sig *bdb_get_header_sig(const void *buf) -{ - const struct bdb_header *h = bdb_get_header(buf); - const uint8_t *b8 = bdb_get_oem_area_0(buf); - - /* Header signature starts after signed data */ - return (const struct bdb_sig *)(b8 + h->signed_size); -} - -const struct bdb_data *bdb_get_data(const void *buf) -{ - const struct bdb_sig *s = bdb_get_header_sig(buf); - const uint8_t *b8 = (const uint8_t *)s; - - /* Data follows header signature */ - return (const struct bdb_data *)(b8 + s->struct_size); -} - -const void *bdb_get_oem_area_1(const void *buf) -{ - const struct bdb_data *p = bdb_get_data(buf); - const uint8_t *b8 = (const uint8_t *)p; - - /* OEM area 1 follows BDB data */ - return b8 + p->struct_size; -} - -const struct bdb_hash *bdb_get_hash(const void *buf, enum bdb_data_type type) -{ - const struct bdb_data *data = bdb_get_data(buf); - const uint8_t *b8 = bdb_get_oem_area_1(buf); - int i; - - /* Hashes follow OEM area 0 */ - b8 += data->oem_area_1_size; - - /* Search for a matching hash */ - for (i = 0; i < data->num_hashes; i++, b8 += data->hash_entry_size) { - const struct bdb_hash *h = (const struct bdb_hash *)b8; - - if (h->type == type) - return h; - } - - return NULL; -} - -const struct bdb_sig *bdb_get_data_sig(const void *buf) -{ - const struct bdb_data *data = bdb_get_data(buf); - const uint8_t *b8 = (const uint8_t *)data; - - /* Data signature starts after signed data */ - return (const struct bdb_sig *)(b8 + data->signed_size); -} - -/*****************************************************************************/ - -int bdb_verify_sig(const struct bdb_key *key, - const struct bdb_sig *sig, - const uint8_t *digest) -{ - /* Key and signature algorithms must match */ - if (key->sig_alg != sig->sig_alg) - return BDB_ERROR_SIG_ALG; - - switch (key->sig_alg) { - case BDB_SIG_ALG_RSA4096: - if (bdb_rsa4096_verify(key->key_data, sig->sig_data, digest)) - return BDB_ERROR_VERIFY_SIG; - break; - case BDB_SIG_ALG_ECSDSA521: - if (bdb_ecdsa521_verify(key->key_data, sig->sig_data, digest)) - return BDB_ERROR_VERIFY_SIG; - break; - case BDB_SIG_ALG_RSA3072B: - if (bdb_rsa3072b_verify(key->key_data, sig->sig_data, digest)) - return BDB_ERROR_VERIFY_SIG; - break; - default: - return BDB_ERROR_VERIFY_SIG; - } - - return BDB_SUCCESS; -} - -int bdb_verify(const void *buf, size_t size, const uint8_t *bdb_key_digest) -{ - const uint8_t *end = (const uint8_t *)buf + size; - const struct bdb_header *h; - const struct bdb_key *bdbkey, *subkey; - const struct bdb_sig *sig; - const struct bdb_data *data; - const void *oem; - uint8_t digest[BDB_SHA256_DIGEST_SIZE]; - int bdb_digest_mismatch; - - /* Make sure buffer doesn't wrap around address space */ - if (end < (const uint8_t *)buf) - return BDB_ERROR_BUF_SIZE; - - /* - * Check header now that we've actually loaded it. We can't guarantee - * this is the same header which was checked before. - */ - h = bdb_get_header(buf); - if (bdb_check_header(h, size)) - return BDB_ERROR_HEADER; - - /* Sanity-check BDB key */ - bdbkey = bdb_get_bdbkey(buf); - if (bdb_check_key(bdbkey, end - (const uint8_t *)bdbkey)) - return BDB_ERROR_BDBKEY; - - /* Calculate BDB key digest and compare with expected */ - if (bdb_sha256(digest, bdbkey, bdbkey->struct_size)) - return BDB_ERROR_DIGEST; - - bdb_digest_mismatch = memcmp(digest, bdb_key_digest, sizeof(digest)); - - /* Make sure OEM area 0 fits */ - oem = bdb_get_oem_area_0(buf); - if (h->oem_area_0_size > end - (const uint8_t *)oem) - return BDB_ERROR_OEM_AREA_0; - - /* Sanity-check subkey */ - subkey = bdb_get_subkey(buf); - if (bdb_check_key(subkey, end - (const uint8_t *)subkey)) - return BDB_ERROR_SUBKEY; - - /* Make sure enough data was signed, and the signed data fits */ - if (h->oem_area_0_size + subkey->struct_size > h->signed_size || - h->signed_size > end - (const uint8_t *)oem) - return BDB_ERROR_BDB_SIGNED_SIZE; - - /* Sanity-check header signature */ - sig = bdb_get_header_sig(buf); - if (bdb_check_sig(sig, end - (const uint8_t *)sig)) - return BDB_ERROR_HEADER_SIG; - - /* Make sure it signed the right amount of data */ - if (sig->signed_size != h->signed_size) - return BDB_ERROR_HEADER_SIG; - - /* Calculate header digest and compare with expected signature */ - if (bdb_sha256(digest, oem, h->signed_size)) - return BDB_ERROR_DIGEST; - if (bdb_verify_sig(bdbkey, sig, digest)) - return BDB_ERROR_HEADER_SIG; - - /* - * Sanity-check data struct. This also checks that OEM area 1 and the - * hashes fit in the remaining buffer. - */ - data = bdb_get_data(buf); - if (bdb_check_data(data, end - (const uint8_t *)data)) - return BDB_ERROR_DATA; - - /* Sanity-check data signature */ - sig = bdb_get_data_sig(buf); - if (bdb_check_sig(sig, end - (const uint8_t *)sig)) - return BDB_ERROR_DATA_SIG; - if (sig->signed_size != data->signed_size) - return BDB_ERROR_DATA_SIG; - - /* Calculate data digest and compare with expected signature */ - if (bdb_sha256(digest, data, data->signed_size)) - return BDB_ERROR_DIGEST; - if (bdb_verify_sig(subkey, sig, digest)) - return BDB_ERROR_DATA_SIG; - - /* Return success or success-other-than-BDB-key-mismatch */ - return bdb_digest_mismatch ? BDB_GOOD_OTHER_THAN_KEY : BDB_SUCCESS; -} |