1 /* Copyright (c) 2014 The Chromium OS Authors. All rights reserved. 2 * Use of this source code is governed by a BSD-style license that can be 3 * found in the LICENSE file. 4 * 5 * Key unpacking functions 6 */ 7 8 #include "2sysincludes.h" 9 #include "2common.h" 10 #include "2rsa.h" 11 #include "vb2_common.h" 12 13 int vb2_unpack_key_data(struct vb2_public_key *key, 14 const uint8_t *key_data, 15 uint32_t key_size) 16 { 17 const uint32_t *buf32 = (const uint32_t *)key_data; 18 uint32_t expected_key_size = vb2_packed_key_size(key->sig_alg); 19 20 /* Make sure buffer is the correct length */ 21 if (!expected_key_size || expected_key_size != key_size) { 22 VB2_DEBUG("Wrong key size for algorithm\n"); 23 return VB2_ERROR_UNPACK_KEY_SIZE; 24 } 25 26 /* Check for alignment */ 27 if (!vb2_aligned(buf32, sizeof(uint32_t))) 28 return VB2_ERROR_UNPACK_KEY_ALIGN; 29 30 key->arrsize = buf32[0]; 31 32 /* Sanity check key array size */ 33 if (key->arrsize * sizeof(uint32_t) != vb2_rsa_sig_size(key->sig_alg)) 34 return VB2_ERROR_UNPACK_KEY_ARRAY_SIZE; 35 36 key->n0inv = buf32[1]; 37 38 /* Arrays point inside the key data */ 39 key->n = buf32 + 2; 40 key->rr = buf32 + 2 + key->arrsize; 41 42 return VB2_SUCCESS; 43 } 44 45 int vb2_unpack_key(struct vb2_public_key *key, 46 const uint8_t *buf, 47 uint32_t size) 48 { 49 const struct vb2_packed_key *pkey = 50 (const struct vb2_packed_key *)buf; 51 uint32_t sig_size; 52 uint32_t min_offset = 0; 53 int rv; 54 55 /* Check magic number */ 56 if (pkey->c.magic != VB2_MAGIC_PACKED_KEY) 57 return VB2_ERROR_UNPACK_KEY_MAGIC; 58 59 rv = vb2_verify_common_header(buf, size); 60 if (rv) 61 return rv; 62 63 /* Make sure key data is inside */ 64 rv = vb2_verify_common_member(pkey, &min_offset, 65 pkey->key_offset, pkey->key_size); 66 if (rv) 67 return rv; 68 69 /* 70 * Check for compatible version. No need to check minor version, since 71 * that's compatible across readers matching the major version, and we 72 * haven't added any new fields. 73 */ 74 if (pkey->c.struct_version_major != VB2_PACKED_KEY_VERSION_MAJOR) 75 return VB2_ERROR_UNPACK_KEY_STRUCT_VERSION; 76 77 /* Copy key algorithms */ 78 key->hash_alg = pkey->hash_alg; 79 if (!vb2_digest_size(key->hash_alg)) 80 return VB2_ERROR_UNPACK_KEY_HASH_ALGORITHM; 81 82 key->sig_alg = pkey->sig_alg; 83 if (key->sig_alg != VB2_SIG_NONE) { 84 sig_size = vb2_rsa_sig_size(key->sig_alg); 85 if (!sig_size) 86 return VB2_ERROR_UNPACK_KEY_SIG_ALGORITHM; 87 rv = vb2_unpack_key_data( 88 key, 89 (const uint8_t *)pkey + pkey->key_offset, 90 pkey->key_size); 91 if (rv) 92 return rv; 93 } 94 95 /* Key description */ 96 key->desc = vb2_common_desc(pkey); 97 key->version = pkey->key_version; 98 key->guid = &pkey->guid; 99 100 return VB2_SUCCESS; 101 } 102
