1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2004 IBM Corporation
4  * Copyright (C) 2014 Intel Corporation
5  */
6 
7 #include <linux/string.h>
8 #include <linux/err.h>
9 #include <linux/tpm.h>
10 #include <linux/tpm_command.h>
11 
12 #include <keys/trusted-type.h>
13 #include <keys/trusted_tpm.h>
14 
15 static struct tpm2_hash tpm2_hash_map[] = {
16 	{HASH_ALGO_SHA1, TPM_ALG_SHA1},
17 	{HASH_ALGO_SHA256, TPM_ALG_SHA256},
18 	{HASH_ALGO_SHA384, TPM_ALG_SHA384},
19 	{HASH_ALGO_SHA512, TPM_ALG_SHA512},
20 	{HASH_ALGO_SM3_256, TPM_ALG_SM3_256},
21 };
22 
23 /**
24  * tpm_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer.
25  *
26  * @buf: an allocated tpm_buf instance
27  * @session_handle: session handle
28  * @nonce: the session nonce, may be NULL if not used
29  * @nonce_len: the session nonce length, may be 0 if not used
30  * @attributes: the session attributes
31  * @hmac: the session HMAC or password, may be NULL if not used
32  * @hmac_len: the session HMAC or password length, maybe 0 if not used
33  */
34 static void tpm2_buf_append_auth(struct tpm_buf *buf, u32 session_handle,
35 				 const u8 *nonce, u16 nonce_len,
36 				 u8 attributes,
37 				 const u8 *hmac, u16 hmac_len)
38 {
39 	tpm_buf_append_u32(buf, 9 + nonce_len + hmac_len);
40 	tpm_buf_append_u32(buf, session_handle);
41 	tpm_buf_append_u16(buf, nonce_len);
42 
43 	if (nonce && nonce_len)
44 		tpm_buf_append(buf, nonce, nonce_len);
45 
46 	tpm_buf_append_u8(buf, attributes);
47 	tpm_buf_append_u16(buf, hmac_len);
48 
49 	if (hmac && hmac_len)
50 		tpm_buf_append(buf, hmac, hmac_len);
51 }
52 
53 /**
54  * tpm2_seal_trusted() - seal the payload of a trusted key
55  *
56  * @chip: TPM chip to use
57  * @payload: the key data in clear and encrypted form
58  * @options: authentication values and other options
59  *
60  * Return: < 0 on error and 0 on success.
61  */
62 int tpm2_seal_trusted(struct tpm_chip *chip,
63 		      struct trusted_key_payload *payload,
64 		      struct trusted_key_options *options)
65 {
66 	unsigned int blob_len;
67 	struct tpm_buf buf;
68 	u32 hash;
69 	int i;
70 	int rc;
71 
72 	for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
73 		if (options->hash == tpm2_hash_map[i].crypto_id) {
74 			hash = tpm2_hash_map[i].tpm_id;
75 			break;
76 		}
77 	}
78 
79 	if (i == ARRAY_SIZE(tpm2_hash_map))
80 		return -EINVAL;
81 
82 	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
83 	if (rc)
84 		return rc;
85 
86 	tpm_buf_append_u32(&buf, options->keyhandle);
87 	tpm2_buf_append_auth(&buf, TPM2_RS_PW,
88 			     NULL /* nonce */, 0,
89 			     0 /* session_attributes */,
90 			     options->keyauth /* hmac */,
91 			     TPM_DIGEST_SIZE);
92 
93 	/* sensitive */
94 	tpm_buf_append_u16(&buf, 4 + TPM_DIGEST_SIZE + payload->key_len + 1);
95 
96 	tpm_buf_append_u16(&buf, TPM_DIGEST_SIZE);
97 	tpm_buf_append(&buf, options->blobauth, TPM_DIGEST_SIZE);
98 	tpm_buf_append_u16(&buf, payload->key_len + 1);
99 	tpm_buf_append(&buf, payload->key, payload->key_len);
100 	tpm_buf_append_u8(&buf, payload->migratable);
101 
102 	/* public */
103 	tpm_buf_append_u16(&buf, 14 + options->policydigest_len);
104 	tpm_buf_append_u16(&buf, TPM_ALG_KEYEDHASH);
105 	tpm_buf_append_u16(&buf, hash);
106 
107 	/* policy */
108 	if (options->policydigest_len) {
109 		tpm_buf_append_u32(&buf, 0);
110 		tpm_buf_append_u16(&buf, options->policydigest_len);
111 		tpm_buf_append(&buf, options->policydigest,
112 			       options->policydigest_len);
113 	} else {
114 		tpm_buf_append_u32(&buf, TPM2_OA_USER_WITH_AUTH);
115 		tpm_buf_append_u16(&buf, 0);
116 	}
117 
118 	/* public parameters */
119 	tpm_buf_append_u16(&buf, TPM_ALG_NULL);
120 	tpm_buf_append_u16(&buf, 0);
121 
122 	/* outside info */
123 	tpm_buf_append_u16(&buf, 0);
124 
125 	/* creation PCR */
126 	tpm_buf_append_u32(&buf, 0);
127 
128 	if (buf.flags & TPM_BUF_OVERFLOW) {
129 		rc = -E2BIG;
130 		goto out;
131 	}
132 
133 	rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
134 	if (rc)
135 		goto out;
136 
137 	blob_len = be32_to_cpup((__be32 *) &buf.data[TPM_HEADER_SIZE]);
138 	if (blob_len > MAX_BLOB_SIZE) {
139 		rc = -E2BIG;
140 		goto out;
141 	}
142 	if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 4 + blob_len) {
143 		rc = -EFAULT;
144 		goto out;
145 	}
146 
147 	memcpy(payload->blob, &buf.data[TPM_HEADER_SIZE + 4], blob_len);
148 	payload->blob_len = blob_len;
149 
150 out:
151 	tpm_buf_destroy(&buf);
152 
153 	if (rc > 0) {
154 		if (tpm2_rc_value(rc) == TPM2_RC_HASH)
155 			rc = -EINVAL;
156 		else
157 			rc = -EPERM;
158 	}
159 
160 	return rc;
161 }
162 
163 /**
164  * tpm2_load_cmd() - execute a TPM2_Load command
165  *
166  * @chip: TPM chip to use
167  * @payload: the key data in clear and encrypted form
168  * @options: authentication values and other options
169  * @blob_handle: returned blob handle
170  *
171  * Return: 0 on success.
172  *        -E2BIG on wrong payload size.
173  *        -EPERM on tpm error status.
174  *        < 0 error from tpm_send.
175  */
176 static int tpm2_load_cmd(struct tpm_chip *chip,
177 			 struct trusted_key_payload *payload,
178 			 struct trusted_key_options *options,
179 			 u32 *blob_handle)
180 {
181 	struct tpm_buf buf;
182 	unsigned int private_len;
183 	unsigned int public_len;
184 	unsigned int blob_len;
185 	int rc;
186 
187 	private_len = be16_to_cpup((__be16 *) &payload->blob[0]);
188 	if (private_len > (payload->blob_len - 2))
189 		return -E2BIG;
190 
191 	public_len = be16_to_cpup((__be16 *) &payload->blob[2 + private_len]);
192 	blob_len = private_len + public_len + 4;
193 	if (blob_len > payload->blob_len)
194 		return -E2BIG;
195 
196 	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD);
197 	if (rc)
198 		return rc;
199 
200 	tpm_buf_append_u32(&buf, options->keyhandle);
201 	tpm2_buf_append_auth(&buf, TPM2_RS_PW,
202 			     NULL /* nonce */, 0,
203 			     0 /* session_attributes */,
204 			     options->keyauth /* hmac */,
205 			     TPM_DIGEST_SIZE);
206 
207 	tpm_buf_append(&buf, payload->blob, blob_len);
208 
209 	if (buf.flags & TPM_BUF_OVERFLOW) {
210 		rc = -E2BIG;
211 		goto out;
212 	}
213 
214 	rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
215 	if (!rc)
216 		*blob_handle = be32_to_cpup(
217 			(__be32 *) &buf.data[TPM_HEADER_SIZE]);
218 
219 out:
220 	tpm_buf_destroy(&buf);
221 
222 	if (rc > 0)
223 		rc = -EPERM;
224 
225 	return rc;
226 }
227 
228 /**
229  * tpm2_unseal_cmd() - execute a TPM2_Unload command
230  *
231  * @chip: TPM chip to use
232  * @payload: the key data in clear and encrypted form
233  * @options: authentication values and other options
234  * @blob_handle: blob handle
235  *
236  * Return: 0 on success
237  *         -EPERM on tpm error status
238  *         < 0 error from tpm_send
239  */
240 static int tpm2_unseal_cmd(struct tpm_chip *chip,
241 			   struct trusted_key_payload *payload,
242 			   struct trusted_key_options *options,
243 			   u32 blob_handle)
244 {
245 	struct tpm_buf buf;
246 	u16 data_len;
247 	u8 *data;
248 	int rc;
249 
250 	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
251 	if (rc)
252 		return rc;
253 
254 	tpm_buf_append_u32(&buf, blob_handle);
255 	tpm2_buf_append_auth(&buf,
256 			     options->policyhandle ?
257 			     options->policyhandle : TPM2_RS_PW,
258 			     NULL /* nonce */, 0,
259 			     TPM2_SA_CONTINUE_SESSION,
260 			     options->blobauth /* hmac */,
261 			     TPM_DIGEST_SIZE);
262 
263 	rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
264 	if (rc > 0)
265 		rc = -EPERM;
266 
267 	if (!rc) {
268 		data_len = be16_to_cpup(
269 			(__be16 *) &buf.data[TPM_HEADER_SIZE + 4]);
270 		if (data_len < MIN_KEY_SIZE ||  data_len > MAX_KEY_SIZE + 1) {
271 			rc = -EFAULT;
272 			goto out;
273 		}
274 
275 		if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 6 + data_len) {
276 			rc = -EFAULT;
277 			goto out;
278 		}
279 		data = &buf.data[TPM_HEADER_SIZE + 6];
280 
281 		memcpy(payload->key, data, data_len - 1);
282 		payload->key_len = data_len - 1;
283 		payload->migratable = data[data_len - 1];
284 	}
285 
286 out:
287 	tpm_buf_destroy(&buf);
288 	return rc;
289 }
290 
291 /**
292  * tpm2_unseal_trusted() - unseal the payload of a trusted key
293  *
294  * @chip: TPM chip to use
295  * @payload: the key data in clear and encrypted form
296  * @options: authentication values and other options
297  *
298  * Return: Same as with tpm_send.
299  */
300 int tpm2_unseal_trusted(struct tpm_chip *chip,
301 			struct trusted_key_payload *payload,
302 			struct trusted_key_options *options)
303 {
304 	u32 blob_handle;
305 	int rc;
306 
307 	rc = tpm2_load_cmd(chip, payload, options, &blob_handle);
308 	if (rc)
309 		return rc;
310 
311 	rc = tpm2_unseal_cmd(chip, payload, options, blob_handle);
312 
313 	return rc;
314 }
315