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11#include <linux/slab.h>
12#include <linux/uaccess.h>
13#include <linux/scatterlist.h>
14#include <linux/crypto.h>
15#include <crypto/hash.h>
16#include <crypto/kpp.h>
17#include <crypto/dh.h>
18#include <keys/user-type.h>
19#include "internal.h"
20
21static ssize_t dh_data_from_key(key_serial_t keyid, void **data)
22{
23 struct key *key;
24 key_ref_t key_ref;
25 long status;
26 ssize_t ret;
27
28 key_ref = lookup_user_key(keyid, 0, KEY_NEED_READ);
29 if (IS_ERR(key_ref)) {
30 ret = -ENOKEY;
31 goto error;
32 }
33
34 key = key_ref_to_ptr(key_ref);
35
36 ret = -EOPNOTSUPP;
37 if (key->type == &key_type_user) {
38 down_read(&key->sem);
39 status = key_validate(key);
40 if (status == 0) {
41 const struct user_key_payload *payload;
42 uint8_t *duplicate;
43
44 payload = user_key_payload_locked(key);
45
46 duplicate = kmemdup(payload->data, payload->datalen,
47 GFP_KERNEL);
48 if (duplicate) {
49 *data = duplicate;
50 ret = payload->datalen;
51 } else {
52 ret = -ENOMEM;
53 }
54 }
55 up_read(&key->sem);
56 }
57
58 key_put(key);
59error:
60 return ret;
61}
62
63static void dh_free_data(struct dh *dh)
64{
65 kzfree(dh->key);
66 kzfree(dh->p);
67 kzfree(dh->g);
68}
69
70struct dh_completion {
71 struct completion completion;
72 int err;
73};
74
75static void dh_crypto_done(struct crypto_async_request *req, int err)
76{
77 struct dh_completion *compl = req->data;
78
79 if (err == -EINPROGRESS)
80 return;
81
82 compl->err = err;
83 complete(&compl->completion);
84}
85
86struct kdf_sdesc {
87 struct shash_desc shash;
88 char ctx[];
89};
90
91static int kdf_alloc(struct kdf_sdesc **sdesc_ret, char *hashname)
92{
93 struct crypto_shash *tfm;
94 struct kdf_sdesc *sdesc;
95 int size;
96 int err;
97
98
99 tfm = crypto_alloc_shash(hashname, 0, 0);
100 if (IS_ERR(tfm)) {
101 pr_info("could not allocate digest TFM handle %s\n", hashname);
102 return PTR_ERR(tfm);
103 }
104
105 err = -EINVAL;
106 if (crypto_shash_digestsize(tfm) == 0)
107 goto out_free_tfm;
108
109 err = -ENOMEM;
110 size = sizeof(struct shash_desc) + crypto_shash_descsize(tfm);
111 sdesc = kmalloc(size, GFP_KERNEL);
112 if (!sdesc)
113 goto out_free_tfm;
114 sdesc->shash.tfm = tfm;
115 sdesc->shash.flags = 0x0;
116
117 *sdesc_ret = sdesc;
118
119 return 0;
120
121out_free_tfm:
122 crypto_free_shash(tfm);
123 return err;
124}
125
126static void kdf_dealloc(struct kdf_sdesc *sdesc)
127{
128 if (!sdesc)
129 return;
130
131 if (sdesc->shash.tfm)
132 crypto_free_shash(sdesc->shash.tfm);
133
134 kzfree(sdesc);
135}
136
137
138
139
140
141
142
143
144
145
146static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen,
147 u8 *dst, unsigned int dlen, unsigned int zlen)
148{
149 struct shash_desc *desc = &sdesc->shash;
150 unsigned int h = crypto_shash_digestsize(desc->tfm);
151 int err = 0;
152 u8 *dst_orig = dst;
153 __be32 counter = cpu_to_be32(1);
154
155 while (dlen) {
156 err = crypto_shash_init(desc);
157 if (err)
158 goto err;
159
160 err = crypto_shash_update(desc, (u8 *)&counter, sizeof(__be32));
161 if (err)
162 goto err;
163
164 if (zlen && h) {
165 u8 tmpbuffer[h];
166 size_t chunk = min_t(size_t, zlen, h);
167 memset(tmpbuffer, 0, chunk);
168
169 do {
170 err = crypto_shash_update(desc, tmpbuffer,
171 chunk);
172 if (err)
173 goto err;
174
175 zlen -= chunk;
176 chunk = min_t(size_t, zlen, h);
177 } while (zlen);
178 }
179
180 if (src && slen) {
181 err = crypto_shash_update(desc, src, slen);
182 if (err)
183 goto err;
184 }
185
186 if (dlen < h) {
187 u8 tmpbuffer[h];
188
189 err = crypto_shash_final(desc, tmpbuffer);
190 if (err)
191 goto err;
192 memcpy(dst, tmpbuffer, dlen);
193 memzero_explicit(tmpbuffer, h);
194 return 0;
195 } else {
196 err = crypto_shash_final(desc, dst);
197 if (err)
198 goto err;
199
200 dlen -= h;
201 dst += h;
202 counter = cpu_to_be32(be32_to_cpu(counter) + 1);
203 }
204 }
205
206 return 0;
207
208err:
209 memzero_explicit(dst_orig, dlen);
210 return err;
211}
212
213static int keyctl_dh_compute_kdf(struct kdf_sdesc *sdesc,
214 char __user *buffer, size_t buflen,
215 uint8_t *kbuf, size_t kbuflen, size_t lzero)
216{
217 uint8_t *outbuf = NULL;
218 int ret;
219
220 outbuf = kmalloc(buflen, GFP_KERNEL);
221 if (!outbuf) {
222 ret = -ENOMEM;
223 goto err;
224 }
225
226 ret = kdf_ctr(sdesc, kbuf, kbuflen, outbuf, buflen, lzero);
227 if (ret)
228 goto err;
229
230 ret = buflen;
231 if (copy_to_user(buffer, outbuf, buflen) != 0)
232 ret = -EFAULT;
233
234err:
235 kzfree(outbuf);
236 return ret;
237}
238
239long __keyctl_dh_compute(struct keyctl_dh_params __user *params,
240 char __user *buffer, size_t buflen,
241 struct keyctl_kdf_params *kdfcopy)
242{
243 long ret;
244 ssize_t dlen;
245 int secretlen;
246 int outlen;
247 struct keyctl_dh_params pcopy;
248 struct dh dh_inputs;
249 struct scatterlist outsg;
250 struct dh_completion compl;
251 struct crypto_kpp *tfm;
252 struct kpp_request *req;
253 uint8_t *secret;
254 uint8_t *outbuf;
255 struct kdf_sdesc *sdesc = NULL;
256
257 if (!params || (!buffer && buflen)) {
258 ret = -EINVAL;
259 goto out1;
260 }
261 if (copy_from_user(&pcopy, params, sizeof(pcopy)) != 0) {
262 ret = -EFAULT;
263 goto out1;
264 }
265
266 if (kdfcopy) {
267 char *hashname;
268
269 if (memchr_inv(kdfcopy->__spare, 0, sizeof(kdfcopy->__spare))) {
270 ret = -EINVAL;
271 goto out1;
272 }
273
274 if (buflen > KEYCTL_KDF_MAX_OUTPUT_LEN ||
275 kdfcopy->otherinfolen > KEYCTL_KDF_MAX_OI_LEN) {
276 ret = -EMSGSIZE;
277 goto out1;
278 }
279
280
281 hashname = strndup_user(kdfcopy->hashname, CRYPTO_MAX_ALG_NAME);
282 if (IS_ERR(hashname)) {
283 ret = PTR_ERR(hashname);
284 goto out1;
285 }
286
287
288 ret = kdf_alloc(&sdesc, hashname);
289 kfree(hashname);
290 if (ret)
291 goto out1;
292 }
293
294 memset(&dh_inputs, 0, sizeof(dh_inputs));
295
296 dlen = dh_data_from_key(pcopy.prime, &dh_inputs.p);
297 if (dlen < 0) {
298 ret = dlen;
299 goto out1;
300 }
301 dh_inputs.p_size = dlen;
302
303 dlen = dh_data_from_key(pcopy.base, &dh_inputs.g);
304 if (dlen < 0) {
305 ret = dlen;
306 goto out2;
307 }
308 dh_inputs.g_size = dlen;
309
310 dlen = dh_data_from_key(pcopy.private, &dh_inputs.key);
311 if (dlen < 0) {
312 ret = dlen;
313 goto out2;
314 }
315 dh_inputs.key_size = dlen;
316
317 secretlen = crypto_dh_key_len(&dh_inputs);
318 secret = kmalloc(secretlen, GFP_KERNEL);
319 if (!secret) {
320 ret = -ENOMEM;
321 goto out2;
322 }
323 ret = crypto_dh_encode_key(secret, secretlen, &dh_inputs);
324 if (ret)
325 goto out3;
326
327 tfm = crypto_alloc_kpp("dh", CRYPTO_ALG_TYPE_KPP, 0);
328 if (IS_ERR(tfm)) {
329 ret = PTR_ERR(tfm);
330 goto out3;
331 }
332
333 ret = crypto_kpp_set_secret(tfm, secret, secretlen);
334 if (ret)
335 goto out4;
336
337 outlen = crypto_kpp_maxsize(tfm);
338
339 if (!kdfcopy) {
340
341
342
343
344 if (buflen == 0) {
345 ret = outlen;
346 goto out4;
347 } else if (outlen > buflen) {
348 ret = -EOVERFLOW;
349 goto out4;
350 }
351 }
352
353 outbuf = kzalloc(kdfcopy ? (outlen + kdfcopy->otherinfolen) : outlen,
354 GFP_KERNEL);
355 if (!outbuf) {
356 ret = -ENOMEM;
357 goto out4;
358 }
359
360 sg_init_one(&outsg, outbuf, outlen);
361
362 req = kpp_request_alloc(tfm, GFP_KERNEL);
363 if (!req) {
364 ret = -ENOMEM;
365 goto out5;
366 }
367
368 kpp_request_set_input(req, NULL, 0);
369 kpp_request_set_output(req, &outsg, outlen);
370 init_completion(&compl.completion);
371 kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
372 CRYPTO_TFM_REQ_MAY_SLEEP,
373 dh_crypto_done, &compl);
374
375
376
377
378
379 ret = crypto_kpp_generate_public_key(req);
380 if (ret == -EINPROGRESS) {
381 wait_for_completion(&compl.completion);
382 ret = compl.err;
383 if (ret)
384 goto out6;
385 }
386
387 if (kdfcopy) {
388
389
390
391
392 if (copy_from_user(outbuf + req->dst_len, kdfcopy->otherinfo,
393 kdfcopy->otherinfolen) != 0) {
394 ret = -EFAULT;
395 goto out6;
396 }
397
398 ret = keyctl_dh_compute_kdf(sdesc, buffer, buflen, outbuf,
399 req->dst_len + kdfcopy->otherinfolen,
400 outlen - req->dst_len);
401 } else if (copy_to_user(buffer, outbuf, req->dst_len) == 0) {
402 ret = req->dst_len;
403 } else {
404 ret = -EFAULT;
405 }
406
407out6:
408 kpp_request_free(req);
409out5:
410 kzfree(outbuf);
411out4:
412 crypto_free_kpp(tfm);
413out3:
414 kzfree(secret);
415out2:
416 dh_free_data(&dh_inputs);
417out1:
418 kdf_dealloc(sdesc);
419 return ret;
420}
421
422long keyctl_dh_compute(struct keyctl_dh_params __user *params,
423 char __user *buffer, size_t buflen,
424 struct keyctl_kdf_params __user *kdf)
425{
426 struct keyctl_kdf_params kdfcopy;
427
428 if (!kdf)
429 return __keyctl_dh_compute(params, buffer, buflen, NULL);
430
431 if (copy_from_user(&kdfcopy, kdf, sizeof(kdfcopy)) != 0)
432 return -EFAULT;
433
434 return __keyctl_dh_compute(params, buffer, buflen, &kdfcopy);
435}
436
