1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ECDSA P1363 signature encoding
4 *
5 * Copyright (c) 2024 Intel Corporation
6 */
7
8#include <linux/err.h>
9#include <linux/module.h>
10#include <crypto/algapi.h>
11#include <crypto/sig.h>
12#include <crypto/internal/ecc.h>
13#include <crypto/internal/sig.h>
14
15struct ecdsa_p1363_ctx {
16 struct crypto_sig *child;
17};
18
19static int ecdsa_p1363_verify(struct crypto_sig *tfm,
20 const void *src, unsigned int slen,
21 const void *digest, unsigned int dlen)
22{
23 struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
24 unsigned int keylen = DIV_ROUND_UP_POW2(crypto_sig_keysize(ctx->child),
25 BITS_PER_BYTE);
26 unsigned int ndigits = DIV_ROUND_UP_POW2(keylen, sizeof(u64));
27 struct ecdsa_raw_sig sig;
28
29 if (slen != 2 * keylen)
30 return -EINVAL;
31
32 ecc_digits_from_bytes(in: src, nbytes: keylen, out: sig.r, ndigits);
33 ecc_digits_from_bytes(in: src + keylen, nbytes: keylen, out: sig.s, ndigits);
34
35 return crypto_sig_verify(tfm: ctx->child, src: &sig, slen: sizeof(sig), digest, dlen);
36}
37
38static unsigned int ecdsa_p1363_key_size(struct crypto_sig *tfm)
39{
40 struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
41
42 return crypto_sig_keysize(tfm: ctx->child);
43}
44
45static unsigned int ecdsa_p1363_max_size(struct crypto_sig *tfm)
46{
47 struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
48
49 return 2 * DIV_ROUND_UP_POW2(crypto_sig_keysize(ctx->child),
50 BITS_PER_BYTE);
51}
52
53static unsigned int ecdsa_p1363_digest_size(struct crypto_sig *tfm)
54{
55 struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
56
57 return crypto_sig_digestsize(tfm: ctx->child);
58}
59
60static int ecdsa_p1363_set_pub_key(struct crypto_sig *tfm,
61 const void *key, unsigned int keylen)
62{
63 struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
64
65 return crypto_sig_set_pubkey(tfm: ctx->child, key, keylen);
66}
67
68static int ecdsa_p1363_init_tfm(struct crypto_sig *tfm)
69{
70 struct sig_instance *inst = sig_alg_instance(tfm);
71 struct crypto_sig_spawn *spawn = sig_instance_ctx(inst);
72 struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
73 struct crypto_sig *child_tfm;
74
75 child_tfm = crypto_spawn_sig(spawn);
76 if (IS_ERR(ptr: child_tfm))
77 return PTR_ERR(ptr: child_tfm);
78
79 ctx->child = child_tfm;
80
81 return 0;
82}
83
84static void ecdsa_p1363_exit_tfm(struct crypto_sig *tfm)
85{
86 struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
87
88 crypto_free_sig(tfm: ctx->child);
89}
90
91static void ecdsa_p1363_free(struct sig_instance *inst)
92{
93 struct crypto_sig_spawn *spawn = sig_instance_ctx(inst);
94
95 crypto_drop_sig(spawn);
96 kfree(objp: inst);
97}
98
99static int ecdsa_p1363_create(struct crypto_template *tmpl, struct rtattr **tb)
100{
101 struct crypto_sig_spawn *spawn;
102 struct sig_instance *inst;
103 struct sig_alg *ecdsa_alg;
104 u32 mask;
105 int err;
106
107 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SIG, mask_ret: &mask);
108 if (err)
109 return err;
110
111 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
112 if (!inst)
113 return -ENOMEM;
114
115 spawn = sig_instance_ctx(inst);
116
117 err = crypto_grab_sig(spawn, inst: sig_crypto_instance(inst),
118 name: crypto_attr_alg_name(rta: tb[1]), type: 0, mask);
119 if (err)
120 goto err_free_inst;
121
122 ecdsa_alg = crypto_spawn_sig_alg(spawn);
123
124 err = -EINVAL;
125 if (strncmp(ecdsa_alg->base.cra_name, "ecdsa", 5) != 0)
126 goto err_free_inst;
127
128 err = crypto_inst_setname(sig_crypto_instance(inst), tmpl->name,
129 &ecdsa_alg->base);
130 if (err)
131 goto err_free_inst;
132
133 inst->alg.base.cra_priority = ecdsa_alg->base.cra_priority;
134 inst->alg.base.cra_ctxsize = sizeof(struct ecdsa_p1363_ctx);
135
136 inst->alg.init = ecdsa_p1363_init_tfm;
137 inst->alg.exit = ecdsa_p1363_exit_tfm;
138
139 inst->alg.verify = ecdsa_p1363_verify;
140 inst->alg.key_size = ecdsa_p1363_key_size;
141 inst->alg.max_size = ecdsa_p1363_max_size;
142 inst->alg.digest_size = ecdsa_p1363_digest_size;
143 inst->alg.set_pub_key = ecdsa_p1363_set_pub_key;
144
145 inst->free = ecdsa_p1363_free;
146
147 err = sig_register_instance(tmpl, inst);
148 if (err) {
149err_free_inst:
150 ecdsa_p1363_free(inst);
151 }
152 return err;
153}
154
155struct crypto_template ecdsa_p1363_tmpl = {
156 .name = "p1363",
157 .create = ecdsa_p1363_create,
158 .module = THIS_MODULE,
159};
160
161MODULE_ALIAS_CRYPTO("p1363");
162

source code of linux/crypto/ecdsa-p1363.c