1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Copyright (c) 2016, Intel Corporation |
4 | * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com> |
5 | */ |
6 | #include <linux/kernel.h> |
7 | #include <linux/export.h> |
8 | #include <linux/err.h> |
9 | #include <linux/string.h> |
10 | #include <crypto/dh.h> |
11 | #include <crypto/kpp.h> |
12 | |
13 | #define DH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + 3 * sizeof(int)) |
14 | |
15 | static inline u8 *dh_pack_data(u8 *dst, u8 *end, const void *src, size_t size) |
16 | { |
17 | if (!dst || size > end - dst) |
18 | return NULL; |
19 | memcpy(dst, src, size); |
20 | return dst + size; |
21 | } |
22 | |
23 | static inline const u8 *dh_unpack_data(void *dst, const void *src, size_t size) |
24 | { |
25 | memcpy(dst, src, size); |
26 | return src + size; |
27 | } |
28 | |
29 | static inline unsigned int dh_data_size(const struct dh *p) |
30 | { |
31 | return p->key_size + p->p_size + p->g_size; |
32 | } |
33 | |
34 | unsigned int crypto_dh_key_len(const struct dh *p) |
35 | { |
36 | return DH_KPP_SECRET_MIN_SIZE + dh_data_size(p); |
37 | } |
38 | EXPORT_SYMBOL_GPL(crypto_dh_key_len); |
39 | |
40 | int crypto_dh_encode_key(char *buf, unsigned int len, const struct dh *params) |
41 | { |
42 | u8 *ptr = buf; |
43 | u8 * const end = ptr + len; |
44 | struct kpp_secret secret = { |
45 | .type = CRYPTO_KPP_SECRET_TYPE_DH, |
46 | .len = len |
47 | }; |
48 | |
49 | if (unlikely(!len)) |
50 | return -EINVAL; |
51 | |
52 | ptr = dh_pack_data(dst: ptr, end, src: &secret, size: sizeof(secret)); |
53 | ptr = dh_pack_data(dst: ptr, end, src: ¶ms->key_size, |
54 | size: sizeof(params->key_size)); |
55 | ptr = dh_pack_data(dst: ptr, end, src: ¶ms->p_size, size: sizeof(params->p_size)); |
56 | ptr = dh_pack_data(dst: ptr, end, src: ¶ms->g_size, size: sizeof(params->g_size)); |
57 | ptr = dh_pack_data(dst: ptr, end, src: params->key, size: params->key_size); |
58 | ptr = dh_pack_data(dst: ptr, end, src: params->p, size: params->p_size); |
59 | ptr = dh_pack_data(dst: ptr, end, src: params->g, size: params->g_size); |
60 | if (ptr != end) |
61 | return -EINVAL; |
62 | return 0; |
63 | } |
64 | EXPORT_SYMBOL_GPL(crypto_dh_encode_key); |
65 | |
66 | int __crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params) |
67 | { |
68 | const u8 *ptr = buf; |
69 | struct kpp_secret secret; |
70 | |
71 | if (unlikely(!buf || len < DH_KPP_SECRET_MIN_SIZE)) |
72 | return -EINVAL; |
73 | |
74 | ptr = dh_unpack_data(dst: &secret, src: ptr, size: sizeof(secret)); |
75 | if (secret.type != CRYPTO_KPP_SECRET_TYPE_DH) |
76 | return -EINVAL; |
77 | |
78 | ptr = dh_unpack_data(dst: ¶ms->key_size, src: ptr, size: sizeof(params->key_size)); |
79 | ptr = dh_unpack_data(dst: ¶ms->p_size, src: ptr, size: sizeof(params->p_size)); |
80 | ptr = dh_unpack_data(dst: ¶ms->g_size, src: ptr, size: sizeof(params->g_size)); |
81 | if (secret.len != crypto_dh_key_len(params)) |
82 | return -EINVAL; |
83 | |
84 | /* Don't allocate memory. Set pointers to data within |
85 | * the given buffer |
86 | */ |
87 | params->key = (void *)ptr; |
88 | params->p = (void *)(ptr + params->key_size); |
89 | params->g = (void *)(ptr + params->key_size + params->p_size); |
90 | |
91 | return 0; |
92 | } |
93 | |
94 | int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params) |
95 | { |
96 | int err; |
97 | |
98 | err = __crypto_dh_decode_key(buf, len, params); |
99 | if (err) |
100 | return err; |
101 | |
102 | /* |
103 | * Don't permit the buffer for 'key' or 'g' to be larger than 'p', since |
104 | * some drivers assume otherwise. |
105 | */ |
106 | if (params->key_size > params->p_size || |
107 | params->g_size > params->p_size) |
108 | return -EINVAL; |
109 | |
110 | /* |
111 | * Don't permit 'p' to be 0. It's not a prime number, and it's subject |
112 | * to corner cases such as 'mod 0' being undefined or |
113 | * crypto_kpp_maxsize() returning 0. |
114 | */ |
115 | if (memchr_inv(p: params->p, c: 0, size: params->p_size) == NULL) |
116 | return -EINVAL; |
117 | |
118 | return 0; |
119 | } |
120 | EXPORT_SYMBOL_GPL(crypto_dh_decode_key); |
121 | |