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b2441318 1// SPDX-License-Identifier: GPL-2.0
8b6e4f2d 2
3d14c5d2 3#include <linux/ceph/ceph_debug.h>
8b6e4f2d
SW
4
5#include <linux/err.h>
6#include <linux/scatterlist.h>
7fea24c6 7#include <linux/sched.h>
5a0e3ad6 8#include <linux/slab.h>
e59dd982
HX
9#include <crypto/aes.h>
10#include <crypto/skcipher.h>
4b2a58ab 11#include <linux/key-type.h>
5b3cc15a 12#include <linux/sched/mm.h>
8b6e4f2d 13
4b2a58ab 14#include <keys/ceph-type.h>
7c3bec0a 15#include <keys/user-type.h>
3d14c5d2 16#include <linux/ceph/decode.h>
8b6e4f2d 17#include "crypto.h"
8b6e4f2d 18
7af3ea18
ID
19/*
20 * Set ->key and ->tfm. The rest of the key should be filled in before
21 * this function is called.
22 */
23static int set_secret(struct ceph_crypto_key *key, void *buf)
24{
25 unsigned int noio_flag;
26 int ret;
27
28 key->key = NULL;
29 key->tfm = NULL;
30
31 switch (key->type) {
32 case CEPH_CRYPTO_NONE:
33 return 0; /* nothing to do */
34 case CEPH_CRYPTO_AES:
35 break;
36 default:
37 return -ENOTSUPP;
38 }
39
40 WARN_ON(!key->len);
41 key->key = kmemdup(buf, key->len, GFP_NOIO);
42 if (!key->key) {
43 ret = -ENOMEM;
44 goto fail;
45 }
46
47 /* crypto_alloc_skcipher() allocates with GFP_KERNEL */
48 noio_flag = memalloc_noio_save();
49 key->tfm = crypto_alloc_skcipher("cbc(aes)", 0, CRYPTO_ALG_ASYNC);
50 memalloc_noio_restore(noio_flag);
51 if (IS_ERR(key->tfm)) {
52 ret = PTR_ERR(key->tfm);
53 key->tfm = NULL;
54 goto fail;
55 }
56
57 ret = crypto_skcipher_setkey(key->tfm, key->key, key->len);
58 if (ret)
59 goto fail;
60
61 return 0;
62
63fail:
64 ceph_crypto_key_destroy(key);
65 return ret;
66}
67
8323c3aa
TV
68int ceph_crypto_key_clone(struct ceph_crypto_key *dst,
69 const struct ceph_crypto_key *src)
70{
71 memcpy(dst, src, sizeof(struct ceph_crypto_key));
7af3ea18 72 return set_secret(dst, src->key);
8323c3aa
TV
73}
74
8b6e4f2d
SW
75int ceph_crypto_key_encode(struct ceph_crypto_key *key, void **p, void *end)
76{
77 if (*p + sizeof(u16) + sizeof(key->created) +
78 sizeof(u16) + key->len > end)
79 return -ERANGE;
80 ceph_encode_16(p, key->type);
81 ceph_encode_copy(p, &key->created, sizeof(key->created));
82 ceph_encode_16(p, key->len);
83 ceph_encode_copy(p, key->key, key->len);
84 return 0;
85}
86
87int ceph_crypto_key_decode(struct ceph_crypto_key *key, void **p, void *end)
88{
7af3ea18
ID
89 int ret;
90
8b6e4f2d
SW
91 ceph_decode_need(p, end, 2*sizeof(u16) + sizeof(key->created), bad);
92 key->type = ceph_decode_16(p);
93 ceph_decode_copy(p, &key->created, sizeof(key->created));
94 key->len = ceph_decode_16(p);
95 ceph_decode_need(p, end, key->len, bad);
7af3ea18
ID
96 ret = set_secret(key, *p);
97 *p += key->len;
98 return ret;
8b6e4f2d
SW
99
100bad:
101 dout("failed to decode crypto key\n");
102 return -EINVAL;
103}
104
105int ceph_crypto_key_unarmor(struct ceph_crypto_key *key, const char *inkey)
106{
107 int inlen = strlen(inkey);
108 int blen = inlen * 3 / 4;
109 void *buf, *p;
110 int ret;
111
112 dout("crypto_key_unarmor %s\n", inkey);
113 buf = kmalloc(blen, GFP_NOFS);
114 if (!buf)
115 return -ENOMEM;
116 blen = ceph_unarmor(buf, inkey, inkey+inlen);
117 if (blen < 0) {
118 kfree(buf);
119 return blen;
120 }
121
122 p = buf;
123 ret = ceph_crypto_key_decode(key, &p, p + blen);
124 kfree(buf);
125 if (ret)
126 return ret;
127 dout("crypto_key_unarmor key %p type %d len %d\n", key,
128 key->type, key->len);
129 return 0;
130}
131
6db2304a
ID
132void ceph_crypto_key_destroy(struct ceph_crypto_key *key)
133{
134 if (key) {
135 kfree(key->key);
136 key->key = NULL;
7af3ea18
ID
137 crypto_free_skcipher(key->tfm);
138 key->tfm = NULL;
6db2304a
ID
139 }
140}
141
cbbfe499 142static const u8 *aes_iv = (u8 *)CEPH_AES_IV;
8b6e4f2d 143
aaef3170
ID
144/*
145 * Should be used for buffers allocated with ceph_kvmalloc().
146 * Currently these are encrypt out-buffer (ceph_buffer) and decrypt
147 * in-buffer (msg front).
148 *
149 * Dispose of @sgt with teardown_sgtable().
150 *
151 * @prealloc_sg is to avoid memory allocation inside sg_alloc_table()
152 * in cases where a single sg is sufficient. No attempt to reduce the
153 * number of sgs by squeezing physically contiguous pages together is
154 * made though, for simplicity.
155 */
156static int setup_sgtable(struct sg_table *sgt, struct scatterlist *prealloc_sg,
157 const void *buf, unsigned int buf_len)
158{
159 struct scatterlist *sg;
160 const bool is_vmalloc = is_vmalloc_addr(buf);
161 unsigned int off = offset_in_page(buf);
162 unsigned int chunk_cnt = 1;
163 unsigned int chunk_len = PAGE_ALIGN(off + buf_len);
164 int i;
165 int ret;
166
167 if (buf_len == 0) {
168 memset(sgt, 0, sizeof(*sgt));
169 return -EINVAL;
170 }
171
172 if (is_vmalloc) {
173 chunk_cnt = chunk_len >> PAGE_SHIFT;
174 chunk_len = PAGE_SIZE;
175 }
176
177 if (chunk_cnt > 1) {
178 ret = sg_alloc_table(sgt, chunk_cnt, GFP_NOFS);
179 if (ret)
180 return ret;
181 } else {
182 WARN_ON(chunk_cnt != 1);
183 sg_init_table(prealloc_sg, 1);
184 sgt->sgl = prealloc_sg;
185 sgt->nents = sgt->orig_nents = 1;
186 }
187
188 for_each_sg(sgt->sgl, sg, sgt->orig_nents, i) {
189 struct page *page;
190 unsigned int len = min(chunk_len - off, buf_len);
191
192 if (is_vmalloc)
193 page = vmalloc_to_page(buf);
194 else
195 page = virt_to_page(buf);
196
197 sg_set_page(sg, page, len, off);
198
199 off = 0;
200 buf += len;
201 buf_len -= len;
202 }
203 WARN_ON(buf_len != 0);
204
205 return 0;
206}
207
208static void teardown_sgtable(struct sg_table *sgt)
209{
210 if (sgt->orig_nents > 1)
211 sg_free_table(sgt);
212}
213
a45f795c
ID
214static int ceph_aes_crypt(const struct ceph_crypto_key *key, bool encrypt,
215 void *buf, int buf_len, int in_len, int *pout_len)
216{
7af3ea18 217 SKCIPHER_REQUEST_ON_STACK(req, key->tfm);
a45f795c
ID
218 struct sg_table sgt;
219 struct scatterlist prealloc_sg;
124f930b 220 char iv[AES_BLOCK_SIZE] __aligned(8);
a45f795c
ID
221 int pad_byte = AES_BLOCK_SIZE - (in_len & (AES_BLOCK_SIZE - 1));
222 int crypt_len = encrypt ? in_len + pad_byte : in_len;
223 int ret;
224
a45f795c
ID
225 WARN_ON(crypt_len > buf_len);
226 if (encrypt)
227 memset(buf + in_len, pad_byte, pad_byte);
228 ret = setup_sgtable(&sgt, &prealloc_sg, buf, crypt_len);
229 if (ret)
7af3ea18 230 return ret;
a45f795c 231
a45f795c 232 memcpy(iv, aes_iv, AES_BLOCK_SIZE);
7af3ea18 233 skcipher_request_set_tfm(req, key->tfm);
a45f795c
ID
234 skcipher_request_set_callback(req, 0, NULL, NULL);
235 skcipher_request_set_crypt(req, sgt.sgl, sgt.sgl, crypt_len, iv);
236
237 /*
238 print_hex_dump(KERN_ERR, "key: ", DUMP_PREFIX_NONE, 16, 1,
239 key->key, key->len, 1);
240 print_hex_dump(KERN_ERR, " in: ", DUMP_PREFIX_NONE, 16, 1,
241 buf, crypt_len, 1);
242 */
243 if (encrypt)
244 ret = crypto_skcipher_encrypt(req);
245 else
246 ret = crypto_skcipher_decrypt(req);
247 skcipher_request_zero(req);
248 if (ret) {
249 pr_err("%s %scrypt failed: %d\n", __func__,
250 encrypt ? "en" : "de", ret);
251 goto out_sgt;
252 }
253 /*
254 print_hex_dump(KERN_ERR, "out: ", DUMP_PREFIX_NONE, 16, 1,
255 buf, crypt_len, 1);
256 */
257
258 if (encrypt) {
259 *pout_len = crypt_len;
260 } else {
261 pad_byte = *(char *)(buf + in_len - 1);
262 if (pad_byte > 0 && pad_byte <= AES_BLOCK_SIZE &&
263 in_len >= pad_byte) {
264 *pout_len = in_len - pad_byte;
265 } else {
266 pr_err("%s got bad padding %d on in_len %d\n",
267 __func__, pad_byte, in_len);
268 ret = -EPERM;
269 goto out_sgt;
270 }
271 }
272
273out_sgt:
274 teardown_sgtable(&sgt);
a45f795c
ID
275 return ret;
276}
277
278int ceph_crypt(const struct ceph_crypto_key *key, bool encrypt,
279 void *buf, int buf_len, int in_len, int *pout_len)
280{
281 switch (key->type) {
282 case CEPH_CRYPTO_NONE:
283 *pout_len = in_len;
284 return 0;
285 case CEPH_CRYPTO_AES:
286 return ceph_aes_crypt(key, encrypt, buf, buf_len, in_len,
287 pout_len);
288 default:
289 return -ENOTSUPP;
290 }
291}
292
efa64c09 293static int ceph_key_preparse(struct key_preparsed_payload *prep)
4b2a58ab
TV
294{
295 struct ceph_crypto_key *ckey;
cf7f601c 296 size_t datalen = prep->datalen;
4b2a58ab
TV
297 int ret;
298 void *p;
299
300 ret = -EINVAL;
cf7f601c 301 if (datalen <= 0 || datalen > 32767 || !prep->data)
4b2a58ab
TV
302 goto err;
303
4b2a58ab
TV
304 ret = -ENOMEM;
305 ckey = kmalloc(sizeof(*ckey), GFP_KERNEL);
306 if (!ckey)
307 goto err;
308
309 /* TODO ceph_crypto_key_decode should really take const input */
cf7f601c
DH
310 p = (void *)prep->data;
311 ret = ceph_crypto_key_decode(ckey, &p, (char*)prep->data+datalen);
4b2a58ab
TV
312 if (ret < 0)
313 goto err_ckey;
314
146aa8b1 315 prep->payload.data[0] = ckey;
efa64c09 316 prep->quotalen = datalen;
4b2a58ab
TV
317 return 0;
318
319err_ckey:
320 kfree(ckey);
321err:
322 return ret;
323}
324
efa64c09
DH
325static void ceph_key_free_preparse(struct key_preparsed_payload *prep)
326{
146aa8b1 327 struct ceph_crypto_key *ckey = prep->payload.data[0];
efa64c09
DH
328 ceph_crypto_key_destroy(ckey);
329 kfree(ckey);
330}
331
efa64c09
DH
332static void ceph_key_destroy(struct key *key)
333{
146aa8b1 334 struct ceph_crypto_key *ckey = key->payload.data[0];
4b2a58ab
TV
335
336 ceph_crypto_key_destroy(ckey);
f0666b1a 337 kfree(ckey);
4b2a58ab
TV
338}
339
340struct key_type key_type_ceph = {
341 .name = "ceph",
efa64c09
DH
342 .preparse = ceph_key_preparse,
343 .free_preparse = ceph_key_free_preparse,
344 .instantiate = generic_key_instantiate,
4b2a58ab
TV
345 .destroy = ceph_key_destroy,
346};
347
348int ceph_crypto_init(void) {
349 return register_key_type(&key_type_ceph);
350}
351
352void ceph_crypto_shutdown(void) {
353 unregister_key_type(&key_type_ceph);
354}