xref: /rk3399_rockchip-uboot/include/android_avb/avb_crypto.h (revision 5b69db0720b90f33ecb7fb666b196bfc90404185) 
1*5b69db07SJason Zhu /*
2*5b69db07SJason Zhu  * Copyright (C) 2016 The Android Open Source Project
3*5b69db07SJason Zhu  *
4*5b69db07SJason Zhu  * Permission is hereby granted, free of charge, to any person
5*5b69db07SJason Zhu  * obtaining a copy of this software and associated documentation
6*5b69db07SJason Zhu  * files (the "Software"), to deal in the Software without
7*5b69db07SJason Zhu  * restriction, including without limitation the rights to use, copy,
8*5b69db07SJason Zhu  * modify, merge, publish, distribute, sublicense, and/or sell copies
9*5b69db07SJason Zhu  * of the Software, and to permit persons to whom the Software is
10*5b69db07SJason Zhu  * furnished to do so, subject to the following conditions:
11*5b69db07SJason Zhu  *
12*5b69db07SJason Zhu  * The above copyright notice and this permission notice shall be
13*5b69db07SJason Zhu  * included in all copies or substantial portions of the Software.
14*5b69db07SJason Zhu  *
15*5b69db07SJason Zhu  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16*5b69db07SJason Zhu  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17*5b69db07SJason Zhu  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18*5b69db07SJason Zhu  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19*5b69db07SJason Zhu  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20*5b69db07SJason Zhu  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21*5b69db07SJason Zhu  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22*5b69db07SJason Zhu  * SOFTWARE.
23*5b69db07SJason Zhu  */
24*5b69db07SJason Zhu 
25*5b69db07SJason Zhu /*
26*5b69db07SJason Zhu #if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
27*5b69db07SJason Zhu #error "Never include this file directly, include libavb.h instead."
28*5b69db07SJason Zhu #endif
29*5b69db07SJason Zhu */
30*5b69db07SJason Zhu 
31*5b69db07SJason Zhu #ifndef AVB_CRYPTO_H_
32*5b69db07SJason Zhu #define AVB_CRYPTO_H_
33*5b69db07SJason Zhu 
34*5b69db07SJason Zhu #include <android_avb/avb_sysdeps.h>
35*5b69db07SJason Zhu 
36*5b69db07SJason Zhu #ifdef __cplusplus
37*5b69db07SJason Zhu extern "C" {
38*5b69db07SJason Zhu #endif
39*5b69db07SJason Zhu 
40*5b69db07SJason Zhu /* Size of a RSA-2048 signature. */
41*5b69db07SJason Zhu #define AVB_RSA2048_NUM_BYTES 256
42*5b69db07SJason Zhu 
43*5b69db07SJason Zhu /* Size of a RSA-4096 signature. */
44*5b69db07SJason Zhu #define AVB_RSA4096_NUM_BYTES 512
45*5b69db07SJason Zhu 
46*5b69db07SJason Zhu /* Size of a RSA-8192 signature. */
47*5b69db07SJason Zhu #define AVB_RSA8192_NUM_BYTES 1024
48*5b69db07SJason Zhu 
49*5b69db07SJason Zhu /* Size in bytes of a SHA-256 digest. */
50*5b69db07SJason Zhu #define AVB_SHA256_DIGEST_SIZE 32
51*5b69db07SJason Zhu 
52*5b69db07SJason Zhu /* Size in bytes of a SHA-512 digest. */
53*5b69db07SJason Zhu #define AVB_SHA512_DIGEST_SIZE 64
54*5b69db07SJason Zhu 
55*5b69db07SJason Zhu /* Algorithms that can be used in the vbmeta image for
56*5b69db07SJason Zhu  * verification. An algorithm consists of a hash type and a signature
57*5b69db07SJason Zhu  * type.
58*5b69db07SJason Zhu  *
59*5b69db07SJason Zhu  * The data used to calculate the hash is the three blocks mentioned
60*5b69db07SJason Zhu  * in the documentation for |AvbVBMetaImageHeader| except for the data
61*5b69db07SJason Zhu  * in the "Authentication data" block.
62*5b69db07SJason Zhu  *
63*5b69db07SJason Zhu  * For signatures with RSA keys, PKCS v1.5 padding is used. The public
64*5b69db07SJason Zhu  * key data is stored in the auxiliary data block, see
65*5b69db07SJason Zhu  * |AvbRSAPublicKeyHeader| for the serialization format.
66*5b69db07SJason Zhu  *
67*5b69db07SJason Zhu  * Each algorithm type is described below:
68*5b69db07SJason Zhu  *
69*5b69db07SJason Zhu  * AVB_ALGORITHM_TYPE_NONE: There is no hash, no signature of the
70*5b69db07SJason Zhu  * data, and no public key. The data cannot be verified. The fields
71*5b69db07SJason Zhu  * |hash_size|, |signature_size|, and |public_key_size| must be zero.
72*5b69db07SJason Zhu  *
73*5b69db07SJason Zhu  * AVB_ALGORITHM_TYPE_SHA256_RSA2048: The hash function used is
74*5b69db07SJason Zhu  * SHA-256, resulting in 32 bytes of hash digest data. This hash is
75*5b69db07SJason Zhu  * signed with a 2048-bit RSA key. The field |hash_size| must be 32,
76*5b69db07SJason Zhu  * |signature_size| must be 256, and the public key data must have
77*5b69db07SJason Zhu  * |key_num_bits| set to 2048.
78*5b69db07SJason Zhu  *
79*5b69db07SJason Zhu  * AVB_ALGORITHM_TYPE_SHA256_RSA4096: Like above, but only with
80*5b69db07SJason Zhu  * a 4096-bit RSA key and |signature_size| set to 512.
81*5b69db07SJason Zhu  *
82*5b69db07SJason Zhu  * AVB_ALGORITHM_TYPE_SHA256_RSA8192: Like above, but only with
83*5b69db07SJason Zhu  * a 8192-bit RSA key and |signature_size| set to 1024.
84*5b69db07SJason Zhu  *
85*5b69db07SJason Zhu  * AVB_ALGORITHM_TYPE_SHA512_RSA2048: The hash function used is
86*5b69db07SJason Zhu  * SHA-512, resulting in 64 bytes of hash digest data. This hash is
87*5b69db07SJason Zhu  * signed with a 2048-bit RSA key. The field |hash_size| must be 64,
88*5b69db07SJason Zhu  * |signature_size| must be 256, and the public key data must have
89*5b69db07SJason Zhu  * |key_num_bits| set to 2048.
90*5b69db07SJason Zhu  *
91*5b69db07SJason Zhu  * AVB_ALGORITHM_TYPE_SHA512_RSA4096: Like above, but only with
92*5b69db07SJason Zhu  * a 4096-bit RSA key and |signature_size| set to 512.
93*5b69db07SJason Zhu  *
94*5b69db07SJason Zhu  * AVB_ALGORITHM_TYPE_SHA512_RSA8192: Like above, but only with
95*5b69db07SJason Zhu  * a 8192-bit RSA key and |signature_size| set to 1024.
96*5b69db07SJason Zhu  */
97*5b69db07SJason Zhu typedef enum {
98*5b69db07SJason Zhu   AVB_ALGORITHM_TYPE_NONE,
99*5b69db07SJason Zhu   AVB_ALGORITHM_TYPE_SHA256_RSA2048,
100*5b69db07SJason Zhu   AVB_ALGORITHM_TYPE_SHA256_RSA4096,
101*5b69db07SJason Zhu   AVB_ALGORITHM_TYPE_SHA256_RSA8192,
102*5b69db07SJason Zhu   AVB_ALGORITHM_TYPE_SHA512_RSA2048,
103*5b69db07SJason Zhu   AVB_ALGORITHM_TYPE_SHA512_RSA4096,
104*5b69db07SJason Zhu   AVB_ALGORITHM_TYPE_SHA512_RSA8192,
105*5b69db07SJason Zhu   _AVB_ALGORITHM_NUM_TYPES
106*5b69db07SJason Zhu } AvbAlgorithmType;
107*5b69db07SJason Zhu 
108*5b69db07SJason Zhu /* Holds algorithm-specific data. The |padding| is needed by avb_rsa_verify. */
109*5b69db07SJason Zhu typedef struct {
110*5b69db07SJason Zhu   const uint8_t* padding;
111*5b69db07SJason Zhu   size_t padding_len;
112*5b69db07SJason Zhu   size_t hash_len;
113*5b69db07SJason Zhu } AvbAlgorithmData;
114*5b69db07SJason Zhu 
115*5b69db07SJason Zhu /* Provides algorithm-specific data for a given |algorithm|. Returns NULL if
116*5b69db07SJason Zhu  * |algorithm| is invalid.
117*5b69db07SJason Zhu  */
118*5b69db07SJason Zhu const AvbAlgorithmData* avb_get_algorithm_data(AvbAlgorithmType algorithm)
119*5b69db07SJason Zhu     AVB_ATTR_WARN_UNUSED_RESULT;
120*5b69db07SJason Zhu 
121*5b69db07SJason Zhu /* The header for a serialized RSA public key.
122*5b69db07SJason Zhu  *
123*5b69db07SJason Zhu  * The size of the key is given by |key_num_bits|, for example 2048
124*5b69db07SJason Zhu  * for a RSA-2048 key. By definition, a RSA public key is the pair (n,
125*5b69db07SJason Zhu  * e) where |n| is the modulus (which can be represented in
126*5b69db07SJason Zhu  * |key_num_bits| bits) and |e| is the public exponent. The exponent
127*5b69db07SJason Zhu  * is not stored since it's assumed to always be 65537.
128*5b69db07SJason Zhu  *
129*5b69db07SJason Zhu  * To optimize verification, the key block includes two precomputed
130*5b69db07SJason Zhu  * values, |n0inv| (fits in 32 bits) and |rr| and can always be
131*5b69db07SJason Zhu  * represented in |key_num_bits|.
132*5b69db07SJason Zhu 
133*5b69db07SJason Zhu  * The value |n0inv| is the value -1/n[0] (mod 2^32). The value |rr|
134*5b69db07SJason Zhu  * is (2^key_num_bits)^2 (mod n).
135*5b69db07SJason Zhu  *
136*5b69db07SJason Zhu  * Following this header is |key_num_bits| bits of |n|, then
137*5b69db07SJason Zhu  * |key_num_bits| bits of |rr|. Both values are stored with most
138*5b69db07SJason Zhu  * significant bit first. Each serialized number takes up
139*5b69db07SJason Zhu  * |key_num_bits|/8 bytes.
140*5b69db07SJason Zhu  *
141*5b69db07SJason Zhu  * All fields in this struct are stored in network byte order when
142*5b69db07SJason Zhu  * serialized.  To generate a copy with fields swapped to native byte
143*5b69db07SJason Zhu  * order, use the function avb_rsa_public_key_header_validate_and_byteswap().
144*5b69db07SJason Zhu  *
145*5b69db07SJason Zhu  * The avb_rsa_verify() function expects a key in this serialized
146*5b69db07SJason Zhu  * format.
147*5b69db07SJason Zhu  *
148*5b69db07SJason Zhu  * The 'avbtool extract_public_key' command can be used to generate a
149*5b69db07SJason Zhu  * serialized RSA public key.
150*5b69db07SJason Zhu  */
151*5b69db07SJason Zhu typedef struct AvbRSAPublicKeyHeader {
152*5b69db07SJason Zhu   uint32_t key_num_bits;
153*5b69db07SJason Zhu   uint32_t n0inv;
154*5b69db07SJason Zhu } AVB_ATTR_PACKED AvbRSAPublicKeyHeader;
155*5b69db07SJason Zhu 
156*5b69db07SJason Zhu /* Copies |src| to |dest| and validates, byte-swapping fields in the
157*5b69db07SJason Zhu  * process if needed. Returns true if valid, false if invalid.
158*5b69db07SJason Zhu  */
159*5b69db07SJason Zhu bool avb_rsa_public_key_header_validate_and_byteswap(
160*5b69db07SJason Zhu     const AvbRSAPublicKeyHeader* src,
161*5b69db07SJason Zhu     AvbRSAPublicKeyHeader* dest) AVB_ATTR_WARN_UNUSED_RESULT;
162*5b69db07SJason Zhu 
163*5b69db07SJason Zhu #ifdef __cplusplus
164*5b69db07SJason Zhu }
165*5b69db07SJason Zhu #endif
166*5b69db07SJason Zhu 
167*5b69db07SJason Zhu #endif /* AVB_CRYPTO_H_ */
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