xref: /linux/drivers/s390/crypto/zcrypt_cca_key.h (revision 1ac731c529cd4d6adbce134754b51ff7d822b145)
1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3  *  Copyright IBM Corp. 2001, 2006
4  *  Author(s): Robert Burroughs
5  *	       Eric Rossman (edrossma@us.ibm.com)
6  *
7  *  Hotplug & misc device support: Jochen Roehrig (roehrig@de.ibm.com)
8  *  Major cleanup & driver split: Martin Schwidefsky <schwidefsky@de.ibm.com>
9  */
10 
11 #ifndef _ZCRYPT_CCA_KEY_H_
12 #define _ZCRYPT_CCA_KEY_H_
13 
14 struct t6_keyblock_hdr {
15 	unsigned short blen;
16 	unsigned short ulen;
17 	unsigned short flags;
18 };
19 
20 /**
21  * mapping for the cca private ME key token.
22  * Three parts of interest here: the header, the private section and
23  * the public section.
24  *
25  * mapping for the cca key token header
26  */
27 struct cca_token_hdr {
28 	unsigned char  token_identifier;
29 	unsigned char  version;
30 	unsigned short token_length;
31 	unsigned char  reserved[4];
32 } __packed;
33 
34 #define CCA_TKN_HDR_ID_EXT 0x1E
35 
36 #define CCA_PVT_USAGE_ALL 0x80
37 
38 /**
39  * mapping for the cca public section
40  * In a private key, the modulus doesn't appear in the public
41  * section. So, an arbitrary public exponent of 0x010001 will be
42  * used, for a section length of 0x0F always.
43  */
44 struct cca_public_sec {
45 	unsigned char  section_identifier;
46 	unsigned char  version;
47 	unsigned short section_length;
48 	unsigned char  reserved[2];
49 	unsigned short exponent_len;
50 	unsigned short modulus_bit_len;
51 	unsigned short modulus_byte_len;    /* In a private key, this is 0 */
52 } __packed;
53 
54 /**
55  * mapping for the cca private CRT key 'token'
56  * The first three parts (the only parts considered in this release)
57  * are: the header, the private section and the public section.
58  * The header and public section are the same as for the
59  * struct cca_private_ext_ME
60  *
61  * Following the structure are the quantities p, q, dp, dq, u, pad,
62  * and modulus, in that order, where pad_len is the modulo 8
63  * complement of the residue modulo 8 of the sum of
64  * (p_len + q_len + dp_len + dq_len + u_len).
65  */
66 struct cca_pvt_ext_crt_sec {
67 	unsigned char  section_identifier;
68 	unsigned char  version;
69 	unsigned short section_length;
70 	unsigned char  private_key_hash[20];
71 	unsigned char  reserved1[4];
72 	unsigned char  key_format;
73 	unsigned char  reserved2;
74 	unsigned char  key_name_hash[20];
75 	unsigned char  key_use_flags[4];
76 	unsigned short p_len;
77 	unsigned short q_len;
78 	unsigned short dp_len;
79 	unsigned short dq_len;
80 	unsigned short u_len;
81 	unsigned short mod_len;
82 	unsigned char  reserved3[4];
83 	unsigned short pad_len;
84 	unsigned char  reserved4[52];
85 	unsigned char  confounder[8];
86 } __packed;
87 
88 #define CCA_PVT_EXT_CRT_SEC_ID_PVT 0x08
89 #define CCA_PVT_EXT_CRT_SEC_FMT_CL 0x40
90 
91 /**
92  * Set up private key fields of a type6 MEX message.
93  *
94  * @mex: pointer to user input data
95  * @p: pointer to memory area for the key
96  *
97  * Returns the size of the key area or negative errno value.
98  */
zcrypt_type6_mex_key_en(struct ica_rsa_modexpo * mex,void * p)99 static inline int zcrypt_type6_mex_key_en(struct ica_rsa_modexpo *mex, void *p)
100 {
101 	static struct cca_token_hdr static_pub_hdr = {
102 		.token_identifier	=  0x1E,
103 	};
104 	static struct cca_public_sec static_pub_sec = {
105 		.section_identifier	=  0x04,
106 	};
107 	struct {
108 		struct t6_keyblock_hdr t6_hdr;
109 		struct cca_token_hdr pubhdr;
110 		struct cca_public_sec pubsec;
111 		char exponent[];
112 	} __packed *key = p;
113 	unsigned char *ptr;
114 
115 	/*
116 	 * The inputdatalength was a selection criteria in the dispatching
117 	 * function zcrypt_rsa_modexpo(). However, do a plausibility check
118 	 * here to make sure the following copy_from_user() can't be utilized
119 	 * to compromise the system.
120 	 */
121 	if (WARN_ON_ONCE(mex->inputdatalength > 512))
122 		return -EINVAL;
123 
124 	memset(key, 0, sizeof(*key));
125 
126 	key->pubhdr = static_pub_hdr;
127 	key->pubsec = static_pub_sec;
128 
129 	/* key parameter block */
130 	ptr = key->exponent;
131 	if (copy_from_user(ptr, mex->b_key, mex->inputdatalength))
132 		return -EFAULT;
133 	ptr += mex->inputdatalength;
134 	/* modulus */
135 	if (copy_from_user(ptr, mex->n_modulus, mex->inputdatalength))
136 		return -EFAULT;
137 
138 	key->pubsec.modulus_bit_len = 8 * mex->inputdatalength;
139 	key->pubsec.modulus_byte_len = mex->inputdatalength;
140 	key->pubsec.exponent_len = mex->inputdatalength;
141 	key->pubsec.section_length = sizeof(key->pubsec) +
142 					2 * mex->inputdatalength;
143 	key->pubhdr.token_length =
144 		key->pubsec.section_length + sizeof(key->pubhdr);
145 	key->t6_hdr.ulen = key->pubhdr.token_length + 4;
146 	key->t6_hdr.blen = key->pubhdr.token_length + 6;
147 
148 	return sizeof(*key) + 2 * mex->inputdatalength;
149 }
150 
151 /**
152  * Set up private key fields of a type6 CRT message.
153  *
154  * @mex: pointer to user input data
155  * @p: pointer to memory area for the key
156  *
157  * Returns the size of the key area or -EFAULT
158  */
zcrypt_type6_crt_key(struct ica_rsa_modexpo_crt * crt,void * p)159 static inline int zcrypt_type6_crt_key(struct ica_rsa_modexpo_crt *crt, void *p)
160 {
161 	static struct cca_public_sec static_cca_pub_sec = {
162 		.section_identifier = 4,
163 		.section_length = 0x000f,
164 		.exponent_len = 0x0003,
165 	};
166 	static char pk_exponent[3] = { 0x01, 0x00, 0x01 };
167 	struct {
168 		struct t6_keyblock_hdr t6_hdr;
169 		struct cca_token_hdr token;
170 		struct cca_pvt_ext_crt_sec pvt;
171 		char key_parts[];
172 	} __packed *key = p;
173 	struct cca_public_sec *pub;
174 	int short_len, long_len, pad_len, key_len, size;
175 
176 	/*
177 	 * The inputdatalength was a selection criteria in the dispatching
178 	 * function zcrypt_rsa_crt(). However, do a plausibility check
179 	 * here to make sure the following copy_from_user() can't be utilized
180 	 * to compromise the system.
181 	 */
182 	if (WARN_ON_ONCE(crt->inputdatalength > 512))
183 		return -EINVAL;
184 
185 	memset(key, 0, sizeof(*key));
186 
187 	short_len = (crt->inputdatalength + 1) / 2;
188 	long_len = short_len + 8;
189 	pad_len = -(3 * long_len + 2 * short_len) & 7;
190 	key_len = 3 * long_len + 2 * short_len + pad_len + crt->inputdatalength;
191 	size = sizeof(*key) + key_len + sizeof(*pub) + 3;
192 
193 	/* parameter block.key block */
194 	key->t6_hdr.blen = size;
195 	key->t6_hdr.ulen = size - 2;
196 
197 	/* key token header */
198 	key->token.token_identifier = CCA_TKN_HDR_ID_EXT;
199 	key->token.token_length = size - 6;
200 
201 	/* private section */
202 	key->pvt.section_identifier = CCA_PVT_EXT_CRT_SEC_ID_PVT;
203 	key->pvt.section_length = sizeof(key->pvt) + key_len;
204 	key->pvt.key_format = CCA_PVT_EXT_CRT_SEC_FMT_CL;
205 	key->pvt.key_use_flags[0] = CCA_PVT_USAGE_ALL;
206 	key->pvt.p_len = key->pvt.dp_len = key->pvt.u_len = long_len;
207 	key->pvt.q_len = key->pvt.dq_len = short_len;
208 	key->pvt.mod_len = crt->inputdatalength;
209 	key->pvt.pad_len = pad_len;
210 
211 	/* key parts */
212 	if (copy_from_user(key->key_parts, crt->np_prime, long_len) ||
213 	    copy_from_user(key->key_parts + long_len,
214 			   crt->nq_prime, short_len) ||
215 	    copy_from_user(key->key_parts + long_len + short_len,
216 			   crt->bp_key, long_len) ||
217 	    copy_from_user(key->key_parts + 2 * long_len + short_len,
218 			   crt->bq_key, short_len) ||
219 	    copy_from_user(key->key_parts + 2 * long_len + 2 * short_len,
220 			   crt->u_mult_inv, long_len))
221 		return -EFAULT;
222 	memset(key->key_parts + 3 * long_len + 2 * short_len + pad_len,
223 	       0xff, crt->inputdatalength);
224 	pub = (struct cca_public_sec *)(key->key_parts + key_len);
225 	*pub = static_cca_pub_sec;
226 	pub->modulus_bit_len = 8 * crt->inputdatalength;
227 	/*
228 	 * In a private key, the modulus doesn't appear in the public
229 	 * section. So, an arbitrary public exponent of 0x010001 will be
230 	 * used.
231 	 */
232 	memcpy((char *)(pub + 1), pk_exponent, 3);
233 
234 	return size;
235 }
236 
237 #endif /* _ZCRYPT_CCA_KEY_H_ */
238