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1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3  * Copyright (c) 2013, Google Inc.
4  *
5  * (C) Copyright 2008 Semihalf
6  *
7  * (C) Copyright 2000-2006
8  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
9  */
10 
11 #ifndef _RSA_H
12 #define _RSA_H
13 
14 #include <errno.h>
15 #include <image.h>
16 
17 /**
18  * struct rsa_public_key - holder for a public key
19  *
20  * An RSA public key consists of a modulus (typically called N), the inverse
21  * and R^2, where R is 2^(# key bits).
22  */
23 
24 struct rsa_public_key {
25 	uint len;		/* len of modulus[] in number of uint32_t */
26 	uint32_t n0inv;		/* -1 / modulus[0] mod 2^32 */
27 	uint32_t *modulus;	/* modulus as little endian array */
28 	uint32_t *rr;		/* R^2 as little endian array */
29 	uint64_t exponent;	/* public exponent */
30 };
31 
32 struct image_sign_info;
33 
34 #if IMAGE_ENABLE_SIGN
35 /**
36  * sign() - calculate and return signature for given input data
37  *
38  * @info:	Specifies key and FIT information
39  * @data:	Pointer to the input data
40  * @data_len:	Data length
41  * @sigp:	Set to an allocated buffer holding the signature
42  * @sig_len:	Set to length of the calculated hash
43  *
44  * This computes input data signature according to selected algorithm.
45  * Resulting signature value is placed in an allocated buffer, the
46  * pointer is returned as *sigp. The length of the calculated
47  * signature is returned via the sig_len pointer argument. The caller
48  * should free *sigp.
49  *
50  * @return: 0, on success, -ve on error
51  */
52 int rsa_sign(struct image_sign_info *info,
53 	     const struct image_region region[],
54 	     int region_count, uint8_t **sigp, uint *sig_len);
55 
56 /**
57  * add_verify_data() - Add verification information to FDT
58  *
59  * Add public key information to the FDT node, suitable for
60  * verification at run-time. The information added depends on the
61  * algorithm being used.
62  *
63  * @info:	Specifies key and FIT information
64  * @keydest:	Destination FDT blob for public key data
65  * @return: 0, on success, -ENOSPC if the keydest FDT blob ran out of space,
66 		other -ve value on error
67 */
68 int rsa_add_verify_data(struct image_sign_info *info, void *keydest);
69 #else
rsa_sign(struct image_sign_info * info,const struct image_region region[],int region_count,uint8_t ** sigp,uint * sig_len)70 static inline int rsa_sign(struct image_sign_info *info,
71 		const struct image_region region[], int region_count,
72 		uint8_t **sigp, uint *sig_len)
73 {
74 	return -ENXIO;
75 }
76 
rsa_add_verify_data(struct image_sign_info * info,void * keydest)77 static inline int rsa_add_verify_data(struct image_sign_info *info,
78 				      void *keydest)
79 {
80 	return -ENXIO;
81 }
82 #endif
83 
84 #if IMAGE_ENABLE_VERIFY
85 /**
86  * rsa_verify() - Verify a signature against some data
87  *
88  * Verify a RSA PKCS1.5 signature against an expected hash.
89  *
90  * @info:	Specifies key and FIT information
91  * @data:	Pointer to the input data
92  * @data_len:	Data length
93  * @sig:	Signature
94  * @sig_len:	Number of bytes in signature
95  * @return 0 if verified, -ve on error
96  */
97 int rsa_verify(struct image_sign_info *info,
98 	       const struct image_region region[], int region_count,
99 	       uint8_t *sig, uint sig_len);
100 #else
rsa_verify(struct image_sign_info * info,const struct image_region region[],int region_count,uint8_t * sig,uint sig_len)101 static inline int rsa_verify(struct image_sign_info *info,
102 		const struct image_region region[], int region_count,
103 		uint8_t *sig, uint sig_len)
104 {
105 	return -ENXIO;
106 }
107 #endif
108 
109 #define RSA2048_BYTES	(2048 / 8)
110 #define RSA4096_BYTES	(4096 / 8)
111 
112 /* This is the minimum/maximum key size we support, in bits */
113 #define RSA_MIN_KEY_BITS	2048
114 #define RSA_MAX_KEY_BITS	4096
115 
116 /* This is the maximum signature length that we support, in bits */
117 #define RSA_MAX_SIG_BITS	4096
118 
119 #endif
120