aboutsummaryrefslogtreecommitdiff
path: root/drivers/s390/crypto/zcrypt_cca_key.h
blob: 6229ba9c56d9c8209e00540c88be38c11b9e0ab5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
/* SPDX-License-Identifier: GPL-2.0+ */
/*
 *  Copyright IBM Corp. 2001, 2006
 *  Author(s): Robert Burroughs
 *	       Eric Rossman (edrossma@us.ibm.com)
 *
 *  Hotplug & misc device support: Jochen Roehrig (roehrig@de.ibm.com)
 *  Major cleanup & driver split: Martin Schwidefsky <schwidefsky@de.ibm.com>
 */

#ifndef _ZCRYPT_CCA_KEY_H_
#define _ZCRYPT_CCA_KEY_H_

struct t6_keyblock_hdr {
	unsigned short blen;
	unsigned short ulen;
	unsigned short flags;
};

/**
 * mapping for the cca private ME key token.
 * Three parts of interest here: the header, the private section and
 * the public section.
 *
 * mapping for the cca key token header
 */
struct cca_token_hdr {
	unsigned char  token_identifier;
	unsigned char  version;
	unsigned short token_length;
	unsigned char  reserved[4];
} __packed;

#define CCA_TKN_HDR_ID_EXT 0x1E

#define CCA_PVT_USAGE_ALL 0x80

/**
 * mapping for the cca public section
 * In a private key, the modulus doesn't appear in the public
 * section. So, an arbitrary public exponent of 0x010001 will be
 * used, for a section length of 0x0F always.
 */
struct cca_public_sec {
	unsigned char  section_identifier;
	unsigned char  version;
	unsigned short section_length;
	unsigned char  reserved[2];
	unsigned short exponent_len;
	unsigned short modulus_bit_len;
	unsigned short modulus_byte_len;    /* In a private key, this is 0 */
} __packed;

/**
 * mapping for the cca private CRT key 'token'
 * The first three parts (the only parts considered in this release)
 * are: the header, the private section and the public section.
 * The header and public section are the same as for the
 * struct cca_private_ext_ME
 *
 * Following the structure are the quantities p, q, dp, dq, u, pad,
 * and modulus, in that order, where pad_len is the modulo 8
 * complement of the residue modulo 8 of the sum of
 * (p_len + q_len + dp_len + dq_len + u_len).
 */
struct cca_pvt_ext_crt_sec {
	unsigned char  section_identifier;
	unsigned char  version;
	unsigned short section_length;
	unsigned char  private_key_hash[20];
	unsigned char  reserved1[4];
	unsigned char  key_format;
	unsigned char  reserved2;
	unsigned char  key_name_hash[20];
	unsigned char  key_use_flags[4];
	unsigned short p_len;
	unsigned short q_len;
	unsigned short dp_len;
	unsigned short dq_len;
	unsigned short u_len;
	unsigned short mod_len;
	unsigned char  reserved3[4];
	unsigned short pad_len;
	unsigned char  reserved4[52];
	unsigned char  confounder[8];
} __packed;

#define CCA_PVT_EXT_CRT_SEC_ID_PVT 0x08
#define CCA_PVT_EXT_CRT_SEC_FMT_CL 0x40

/**
 * Set up private key fields of a type6 MEX message. The _pad variant
 * strips leading zeroes from the b_key.
 * Note that all numerics in the key token are big-endian,
 * while the entries in the key block header are little-endian.
 *
 * @mex: pointer to user input data
 * @p: pointer to memory area for the key
 *
 * Returns the size of the key area or negative errno value.
 */
static inline int zcrypt_type6_mex_key_en(struct ica_rsa_modexpo *mex, void *p)
{
	static struct cca_token_hdr static_pub_hdr = {
		.token_identifier	=  0x1E,
	};
	static struct cca_public_sec static_pub_sec = {
		.section_identifier	=  0x04,
	};
	struct {
		struct t6_keyblock_hdr t6_hdr;
		struct cca_token_hdr pubhdr;
		struct cca_public_sec pubsec;
		char exponent[0];
	} __packed *key = p;
	unsigned char *temp;
	int i;

	/*
	 * The inputdatalength was a selection criteria in the dispatching
	 * function zcrypt_rsa_modexpo(). However, do a plausibility check
	 * here to make sure the following copy_from_user() can't be utilized
	 * to compromise the system.
	 */
	if (WARN_ON_ONCE(mex->inputdatalength > 512))
		return -EINVAL;

	memset(key, 0, sizeof(*key));

	key->pubhdr = static_pub_hdr;
	key->pubsec = static_pub_sec;

	/* key parameter block */
	temp = key->exponent;
	if (copy_from_user(temp, mex->b_key, mex->inputdatalength))
		return -EFAULT;
	/* Strip leading zeroes from b_key. */
	for (i = 0; i < mex->inputdatalength; i++)
		if (temp[i])
			break;
	if (i >= mex->inputdatalength)
		return -EINVAL;
	memmove(temp, temp + i, mex->inputdatalength - i);
	temp += mex->inputdatalength - i;
	/* modulus */
	if (copy_from_user(temp, mex->n_modulus, mex->inputdatalength))
		return -EFAULT;

	key->pubsec.modulus_bit_len = 8 * mex->inputdatalength;
	key->pubsec.modulus_byte_len = mex->inputdatalength;
	key->pubsec.exponent_len = mex->inputdatalength - i;
	key->pubsec.section_length = sizeof(key->pubsec) +
					2 * mex->inputdatalength - i;
	key->pubhdr.token_length =
		key->pubsec.section_length + sizeof(key->pubhdr);
	key->t6_hdr.ulen = key->pubhdr.token_length + 4;
	key->t6_hdr.blen = key->pubhdr.token_length + 6;
	return sizeof(*key) + 2 * mex->inputdatalength - i;
}

/**
 * Set up private key fields of a type6 CRT message.
 * Note that all numerics in the key token are big-endian,
 * while the entries in the key block header are little-endian.
 *
 * @mex: pointer to user input data
 * @p: pointer to memory area for the key
 *
 * Returns the size of the key area or -EFAULT
 */
static inline int zcrypt_type6_crt_key(struct ica_rsa_modexpo_crt *crt, void *p)
{
	static struct cca_public_sec static_cca_pub_sec = {
		.section_identifier = 4,
		.section_length = 0x000f,
		.exponent_len = 0x0003,
	};
	static char pk_exponent[3] = { 0x01, 0x00, 0x01 };
	struct {
		struct t6_keyblock_hdr t6_hdr;
		struct cca_token_hdr token;
		struct cca_pvt_ext_crt_sec pvt;
		char key_parts[0];
	} __packed *key = p;
	struct cca_public_sec *pub;
	int short_len, long_len, pad_len, key_len, size;

	/*
	 * The inputdatalength was a selection criteria in the dispatching
	 * function zcrypt_rsa_crt(). However, do a plausibility check
	 * here to make sure the following copy_from_user() can't be utilized
	 * to compromise the system.
	 */
	if (WARN_ON_ONCE(crt->inputdatalength > 512))
		return -EINVAL;

	memset(key, 0, sizeof(*key));

	short_len = (crt->inputdatalength + 1) / 2;
	long_len = short_len + 8;
	pad_len = -(3 * long_len + 2 * short_len) & 7;
	key_len = 3 * long_len + 2 * short_len + pad_len + crt->inputdatalength;
	size = sizeof(*key) + key_len + sizeof(*pub) + 3;

	/* parameter block.key block */
	key->t6_hdr.blen = size;
	key->t6_hdr.ulen = size - 2;

	/* key token header */
	key->token.token_identifier = CCA_TKN_HDR_ID_EXT;
	key->token.token_length = size - 6;

	/* private section */
	key->pvt.section_identifier = CCA_PVT_EXT_CRT_SEC_ID_PVT;
	key->pvt.section_length = sizeof(key->pvt) + key_len;
	key->pvt.key_format = CCA_PVT_EXT_CRT_SEC_FMT_CL;
	key->pvt.key_use_flags[0] = CCA_PVT_USAGE_ALL;
	key->pvt.p_len = key->pvt.dp_len = key->pvt.u_len = long_len;
	key->pvt.q_len = key->pvt.dq_len = short_len;
	key->pvt.mod_len = crt->inputdatalength;
	key->pvt.pad_len = pad_len;

	/* key parts */
	if (copy_from_user(key->key_parts, crt->np_prime, long_len) ||
	    copy_from_user(key->key_parts + long_len,
			   crt->nq_prime, short_len) ||
	    copy_from_user(key->key_parts + long_len + short_len,
			   crt->bp_key, long_len) ||
	    copy_from_user(key->key_parts + 2 * long_len + short_len,
			   crt->bq_key, short_len) ||
	    copy_from_user(key->key_parts + 2 * long_len + 2 * short_len,
			   crt->u_mult_inv, long_len))
		return -EFAULT;
	memset(key->key_parts + 3 * long_len + 2 * short_len + pad_len,
	       0xff, crt->inputdatalength);
	pub = (struct cca_public_sec *)(key->key_parts + key_len);
	*pub = static_cca_pub_sec;
	pub->modulus_bit_len = 8 * crt->inputdatalength;
	/*
	 * In a private key, the modulus doesn't appear in the public
	 * section. So, an arbitrary public exponent of 0x010001 will be
	 * used.
	 */
	memcpy((char *)(pub + 1), pk_exponent, 3);
	return size;
}

#endif /* _ZCRYPT_CCA_KEY_H_ */