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Commit | Line | Data |
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17926a79 DH |
1 | /* Kerberos-based RxRPC security |
2 | * | |
3 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
9b6d5398 JP |
12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
13 | ||
1afe593b | 14 | #include <crypto/skcipher.h> |
17926a79 DH |
15 | #include <linux/module.h> |
16 | #include <linux/net.h> | |
17 | #include <linux/skbuff.h> | |
18 | #include <linux/udp.h> | |
17926a79 DH |
19 | #include <linux/scatterlist.h> |
20 | #include <linux/ctype.h> | |
5a0e3ad6 | 21 | #include <linux/slab.h> |
17926a79 DH |
22 | #include <net/sock.h> |
23 | #include <net/af_rxrpc.h> | |
33941284 | 24 | #include <keys/rxrpc-type.h> |
17926a79 DH |
25 | #include "ar-internal.h" |
26 | ||
27 | #define RXKAD_VERSION 2 | |
28 | #define MAXKRB5TICKETLEN 1024 | |
29 | #define RXKAD_TKT_TYPE_KERBEROS_V5 256 | |
30 | #define ANAME_SZ 40 /* size of authentication name */ | |
31 | #define INST_SZ 40 /* size of principal's instance */ | |
32 | #define REALM_SZ 40 /* size of principal's auth domain */ | |
33 | #define SNAME_SZ 40 /* size of service name */ | |
34 | ||
17926a79 DH |
35 | struct rxkad_level1_hdr { |
36 | __be32 data_size; /* true data size (excluding padding) */ | |
37 | }; | |
38 | ||
39 | struct rxkad_level2_hdr { | |
40 | __be32 data_size; /* true data size (excluding padding) */ | |
41 | __be32 checksum; /* decrypted data checksum */ | |
42 | }; | |
43 | ||
17926a79 DH |
44 | /* |
45 | * this holds a pinned cipher so that keventd doesn't get called by the cipher | |
46 | * alloc routine, but since we have it to hand, we use it to decrypt RESPONSE | |
47 | * packets | |
48 | */ | |
1afe593b | 49 | static struct crypto_skcipher *rxkad_ci; |
17926a79 DH |
50 | static DEFINE_MUTEX(rxkad_ci_mutex); |
51 | ||
52 | /* | |
53 | * initialise connection security | |
54 | */ | |
55 | static int rxkad_init_connection_security(struct rxrpc_connection *conn) | |
56 | { | |
1afe593b | 57 | struct crypto_skcipher *ci; |
33941284 | 58 | struct rxrpc_key_token *token; |
17926a79 DH |
59 | int ret; |
60 | ||
19ffa01c | 61 | _enter("{%d},{%x}", conn->debug_id, key_serial(conn->params.key)); |
17926a79 | 62 | |
19ffa01c | 63 | token = conn->params.key->payload.data[0]; |
33941284 | 64 | conn->security_ix = token->security_index; |
17926a79 | 65 | |
1afe593b | 66 | ci = crypto_alloc_skcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC); |
17926a79 DH |
67 | if (IS_ERR(ci)) { |
68 | _debug("no cipher"); | |
69 | ret = PTR_ERR(ci); | |
70 | goto error; | |
71 | } | |
72 | ||
1afe593b HX |
73 | if (crypto_skcipher_setkey(ci, token->kad->session_key, |
74 | sizeof(token->kad->session_key)) < 0) | |
17926a79 DH |
75 | BUG(); |
76 | ||
19ffa01c | 77 | switch (conn->params.security_level) { |
17926a79 DH |
78 | case RXRPC_SECURITY_PLAIN: |
79 | break; | |
80 | case RXRPC_SECURITY_AUTH: | |
81 | conn->size_align = 8; | |
82 | conn->security_size = sizeof(struct rxkad_level1_hdr); | |
17926a79 DH |
83 | break; |
84 | case RXRPC_SECURITY_ENCRYPT: | |
85 | conn->size_align = 8; | |
86 | conn->security_size = sizeof(struct rxkad_level2_hdr); | |
17926a79 DH |
87 | break; |
88 | default: | |
89 | ret = -EKEYREJECTED; | |
90 | goto error; | |
91 | } | |
92 | ||
93 | conn->cipher = ci; | |
94 | ret = 0; | |
95 | error: | |
96 | _leave(" = %d", ret); | |
97 | return ret; | |
98 | } | |
99 | ||
100 | /* | |
101 | * prime the encryption state with the invariant parts of a connection's | |
102 | * description | |
103 | */ | |
a263629d | 104 | static int rxkad_prime_packet_security(struct rxrpc_connection *conn) |
17926a79 | 105 | { |
33941284 | 106 | struct rxrpc_key_token *token; |
1afe593b | 107 | SKCIPHER_REQUEST_ON_STACK(req, conn->cipher); |
a263629d | 108 | struct scatterlist sg; |
17926a79 | 109 | struct rxrpc_crypt iv; |
a263629d HX |
110 | __be32 *tmpbuf; |
111 | size_t tmpsize = 4 * sizeof(__be32); | |
17926a79 DH |
112 | |
113 | _enter(""); | |
114 | ||
19ffa01c | 115 | if (!conn->params.key) |
a263629d HX |
116 | return 0; |
117 | ||
118 | tmpbuf = kmalloc(tmpsize, GFP_KERNEL); | |
119 | if (!tmpbuf) | |
120 | return -ENOMEM; | |
17926a79 | 121 | |
19ffa01c | 122 | token = conn->params.key->payload.data[0]; |
33941284 | 123 | memcpy(&iv, token->kad->session_key, sizeof(iv)); |
17926a79 | 124 | |
a263629d HX |
125 | tmpbuf[0] = htonl(conn->proto.epoch); |
126 | tmpbuf[1] = htonl(conn->proto.cid); | |
127 | tmpbuf[2] = 0; | |
128 | tmpbuf[3] = htonl(conn->security_ix); | |
1afe593b | 129 | |
a263629d | 130 | sg_init_one(&sg, tmpbuf, tmpsize); |
1afe593b HX |
131 | skcipher_request_set_tfm(req, conn->cipher); |
132 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
a263629d | 133 | skcipher_request_set_crypt(req, &sg, &sg, tmpsize, iv.x); |
1afe593b HX |
134 | crypto_skcipher_encrypt(req); |
135 | skcipher_request_zero(req); | |
17926a79 | 136 | |
a263629d HX |
137 | memcpy(&conn->csum_iv, tmpbuf + 2, sizeof(conn->csum_iv)); |
138 | kfree(tmpbuf); | |
139 | _leave(" = 0"); | |
140 | return 0; | |
17926a79 DH |
141 | } |
142 | ||
143 | /* | |
144 | * partially encrypt a packet (level 1 security) | |
145 | */ | |
146 | static int rxkad_secure_packet_auth(const struct rxrpc_call *call, | |
147 | struct sk_buff *skb, | |
148 | u32 data_size, | |
149 | void *sechdr) | |
150 | { | |
151 | struct rxrpc_skb_priv *sp; | |
1afe593b | 152 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
a263629d | 153 | struct rxkad_level1_hdr hdr; |
17926a79 | 154 | struct rxrpc_crypt iv; |
a263629d | 155 | struct scatterlist sg; |
17926a79 DH |
156 | u16 check; |
157 | ||
158 | sp = rxrpc_skb(skb); | |
159 | ||
160 | _enter(""); | |
161 | ||
5a924b89 | 162 | check = sp->hdr.seq ^ call->call_id; |
0d12f8a4 | 163 | data_size |= (u32)check << 16; |
17926a79 | 164 | |
a263629d HX |
165 | hdr.data_size = htonl(data_size); |
166 | memcpy(sechdr, &hdr, sizeof(hdr)); | |
17926a79 DH |
167 | |
168 | /* start the encryption afresh */ | |
169 | memset(&iv, 0, sizeof(iv)); | |
17926a79 | 170 | |
a263629d | 171 | sg_init_one(&sg, sechdr, 8); |
1afe593b HX |
172 | skcipher_request_set_tfm(req, call->conn->cipher); |
173 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
a263629d | 174 | skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x); |
1afe593b HX |
175 | crypto_skcipher_encrypt(req); |
176 | skcipher_request_zero(req); | |
17926a79 | 177 | |
17926a79 DH |
178 | _leave(" = 0"); |
179 | return 0; | |
180 | } | |
181 | ||
182 | /* | |
183 | * wholly encrypt a packet (level 2 security) | |
184 | */ | |
185 | static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call, | |
b4f1342f DH |
186 | struct sk_buff *skb, |
187 | u32 data_size, | |
188 | void *sechdr) | |
17926a79 | 189 | { |
33941284 | 190 | const struct rxrpc_key_token *token; |
a263629d | 191 | struct rxkad_level2_hdr rxkhdr; |
17926a79 | 192 | struct rxrpc_skb_priv *sp; |
1afe593b | 193 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 DH |
194 | struct rxrpc_crypt iv; |
195 | struct scatterlist sg[16]; | |
196 | struct sk_buff *trailer; | |
95c96174 | 197 | unsigned int len; |
17926a79 DH |
198 | u16 check; |
199 | int nsg; | |
1afe593b | 200 | int err; |
17926a79 DH |
201 | |
202 | sp = rxrpc_skb(skb); | |
203 | ||
204 | _enter(""); | |
205 | ||
5a924b89 | 206 | check = sp->hdr.seq ^ call->call_id; |
17926a79 | 207 | |
0d12f8a4 | 208 | rxkhdr.data_size = htonl(data_size | (u32)check << 16); |
17926a79 | 209 | rxkhdr.checksum = 0; |
a263629d | 210 | memcpy(sechdr, &rxkhdr, sizeof(rxkhdr)); |
17926a79 DH |
211 | |
212 | /* encrypt from the session key */ | |
19ffa01c | 213 | token = call->conn->params.key->payload.data[0]; |
33941284 | 214 | memcpy(&iv, token->kad->session_key, sizeof(iv)); |
17926a79 | 215 | |
68e3f5dd | 216 | sg_init_one(&sg[0], sechdr, sizeof(rxkhdr)); |
1afe593b HX |
217 | skcipher_request_set_tfm(req, call->conn->cipher); |
218 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
a263629d | 219 | skcipher_request_set_crypt(req, &sg[0], &sg[0], sizeof(rxkhdr), iv.x); |
1afe593b | 220 | crypto_skcipher_encrypt(req); |
17926a79 DH |
221 | |
222 | /* we want to encrypt the skbuff in-place */ | |
223 | nsg = skb_cow_data(skb, 0, &trailer); | |
1afe593b | 224 | err = -ENOMEM; |
17926a79 | 225 | if (nsg < 0 || nsg > 16) |
1afe593b | 226 | goto out; |
17926a79 DH |
227 | |
228 | len = data_size + call->conn->size_align - 1; | |
229 | len &= ~(call->conn->size_align - 1); | |
230 | ||
51c739d1 DM |
231 | sg_init_table(sg, nsg); |
232 | skb_to_sgvec(skb, sg, 0, len); | |
1afe593b | 233 | skcipher_request_set_crypt(req, sg, sg, len, iv.x); |
1afe593b | 234 | crypto_skcipher_encrypt(req); |
17926a79 DH |
235 | |
236 | _leave(" = 0"); | |
1afe593b HX |
237 | err = 0; |
238 | ||
239 | out: | |
240 | skcipher_request_zero(req); | |
241 | return err; | |
17926a79 DH |
242 | } |
243 | ||
244 | /* | |
245 | * checksum an RxRPC packet header | |
246 | */ | |
a263629d | 247 | static int rxkad_secure_packet(struct rxrpc_call *call, |
b4f1342f DH |
248 | struct sk_buff *skb, |
249 | size_t data_size, | |
250 | void *sechdr) | |
17926a79 DH |
251 | { |
252 | struct rxrpc_skb_priv *sp; | |
1afe593b | 253 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 | 254 | struct rxrpc_crypt iv; |
a263629d | 255 | struct scatterlist sg; |
0d12f8a4 | 256 | u32 x, y; |
17926a79 DH |
257 | int ret; |
258 | ||
259 | sp = rxrpc_skb(skb); | |
260 | ||
261 | _enter("{%d{%x}},{#%u},%zu,", | |
19ffa01c DH |
262 | call->debug_id, key_serial(call->conn->params.key), |
263 | sp->hdr.seq, data_size); | |
17926a79 DH |
264 | |
265 | if (!call->conn->cipher) | |
266 | return 0; | |
267 | ||
19ffa01c | 268 | ret = key_validate(call->conn->params.key); |
17926a79 DH |
269 | if (ret < 0) |
270 | return ret; | |
271 | ||
272 | /* continue encrypting from where we left off */ | |
273 | memcpy(&iv, call->conn->csum_iv.x, sizeof(iv)); | |
17926a79 DH |
274 | |
275 | /* calculate the security checksum */ | |
01a90a45 | 276 | x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT); |
0d12f8a4 | 277 | x |= sp->hdr.seq & 0x3fffffff; |
5a924b89 | 278 | call->crypto_buf[0] = htonl(call->call_id); |
a263629d | 279 | call->crypto_buf[1] = htonl(x); |
1afe593b | 280 | |
a263629d | 281 | sg_init_one(&sg, call->crypto_buf, 8); |
1afe593b HX |
282 | skcipher_request_set_tfm(req, call->conn->cipher); |
283 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
a263629d | 284 | skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x); |
1afe593b HX |
285 | crypto_skcipher_encrypt(req); |
286 | skcipher_request_zero(req); | |
17926a79 | 287 | |
a263629d | 288 | y = ntohl(call->crypto_buf[1]); |
91e916cf AV |
289 | y = (y >> 16) & 0xffff; |
290 | if (y == 0) | |
291 | y = 1; /* zero checksums are not permitted */ | |
0d12f8a4 | 292 | sp->hdr.cksum = y; |
17926a79 | 293 | |
19ffa01c | 294 | switch (call->conn->params.security_level) { |
17926a79 DH |
295 | case RXRPC_SECURITY_PLAIN: |
296 | ret = 0; | |
297 | break; | |
298 | case RXRPC_SECURITY_AUTH: | |
299 | ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr); | |
300 | break; | |
301 | case RXRPC_SECURITY_ENCRYPT: | |
302 | ret = rxkad_secure_packet_encrypt(call, skb, data_size, | |
303 | sechdr); | |
304 | break; | |
305 | default: | |
306 | ret = -EPERM; | |
307 | break; | |
308 | } | |
309 | ||
91e916cf | 310 | _leave(" = %d [set %hx]", ret, y); |
17926a79 DH |
311 | return ret; |
312 | } | |
313 | ||
314 | /* | |
315 | * decrypt partial encryption on a packet (level 1 security) | |
316 | */ | |
5a42976d | 317 | static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb, |
248f219c | 318 | unsigned int offset, unsigned int len, |
5a42976d | 319 | rxrpc_seq_t seq) |
17926a79 DH |
320 | { |
321 | struct rxkad_level1_hdr sechdr; | |
1afe593b | 322 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 | 323 | struct rxrpc_crypt iv; |
68e3f5dd | 324 | struct scatterlist sg[16]; |
17926a79 DH |
325 | struct sk_buff *trailer; |
326 | u32 data_size, buf; | |
327 | u16 check; | |
68e3f5dd | 328 | int nsg; |
17926a79 DH |
329 | |
330 | _enter(""); | |
331 | ||
248f219c | 332 | if (len < 8) { |
5a42976d DH |
333 | rxrpc_abort_call("V1H", call, seq, RXKADSEALEDINCON, EPROTO); |
334 | goto protocol_error; | |
335 | } | |
17926a79 | 336 | |
248f219c DH |
337 | /* Decrypt the skbuff in-place. TODO: We really want to decrypt |
338 | * directly into the target buffer. | |
339 | */ | |
68e3f5dd HX |
340 | nsg = skb_cow_data(skb, 0, &trailer); |
341 | if (nsg < 0 || nsg > 16) | |
17926a79 DH |
342 | goto nomem; |
343 | ||
68e3f5dd | 344 | sg_init_table(sg, nsg); |
248f219c | 345 | skb_to_sgvec(skb, sg, offset, 8); |
17926a79 DH |
346 | |
347 | /* start the decryption afresh */ | |
348 | memset(&iv, 0, sizeof(iv)); | |
17926a79 | 349 | |
1afe593b HX |
350 | skcipher_request_set_tfm(req, call->conn->cipher); |
351 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
352 | skcipher_request_set_crypt(req, sg, sg, 8, iv.x); | |
1afe593b HX |
353 | crypto_skcipher_decrypt(req); |
354 | skcipher_request_zero(req); | |
17926a79 | 355 | |
5a42976d | 356 | /* Extract the decrypted packet length */ |
248f219c | 357 | if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) { |
5a42976d DH |
358 | rxrpc_abort_call("XV1", call, seq, RXKADDATALEN, EPROTO); |
359 | goto protocol_error; | |
360 | } | |
248f219c DH |
361 | offset += sizeof(sechdr); |
362 | len -= sizeof(sechdr); | |
17926a79 DH |
363 | |
364 | buf = ntohl(sechdr.data_size); | |
365 | data_size = buf & 0xffff; | |
366 | ||
367 | check = buf >> 16; | |
5a42976d | 368 | check ^= seq ^ call->call_id; |
17926a79 DH |
369 | check &= 0xffff; |
370 | if (check != 0) { | |
5a42976d | 371 | rxrpc_abort_call("V1C", call, seq, RXKADSEALEDINCON, EPROTO); |
17926a79 DH |
372 | goto protocol_error; |
373 | } | |
374 | ||
248f219c | 375 | if (data_size > len) { |
5a42976d DH |
376 | rxrpc_abort_call("V1L", call, seq, RXKADDATALEN, EPROTO); |
377 | goto protocol_error; | |
378 | } | |
17926a79 DH |
379 | |
380 | _leave(" = 0 [dlen=%x]", data_size); | |
381 | return 0; | |
382 | ||
17926a79 | 383 | protocol_error: |
26cb02aa | 384 | rxrpc_send_abort_packet(call); |
17926a79 DH |
385 | _leave(" = -EPROTO"); |
386 | return -EPROTO; | |
387 | ||
388 | nomem: | |
389 | _leave(" = -ENOMEM"); | |
390 | return -ENOMEM; | |
391 | } | |
392 | ||
393 | /* | |
394 | * wholly decrypt a packet (level 2 security) | |
395 | */ | |
5a42976d | 396 | static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb, |
248f219c | 397 | unsigned int offset, unsigned int len, |
5a42976d | 398 | rxrpc_seq_t seq) |
17926a79 | 399 | { |
33941284 | 400 | const struct rxrpc_key_token *token; |
17926a79 | 401 | struct rxkad_level2_hdr sechdr; |
1afe593b | 402 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 DH |
403 | struct rxrpc_crypt iv; |
404 | struct scatterlist _sg[4], *sg; | |
405 | struct sk_buff *trailer; | |
406 | u32 data_size, buf; | |
407 | u16 check; | |
408 | int nsg; | |
409 | ||
410 | _enter(",{%d}", skb->len); | |
411 | ||
248f219c | 412 | if (len < 8) { |
5a42976d DH |
413 | rxrpc_abort_call("V2H", call, seq, RXKADSEALEDINCON, EPROTO); |
414 | goto protocol_error; | |
415 | } | |
17926a79 | 416 | |
248f219c DH |
417 | /* Decrypt the skbuff in-place. TODO: We really want to decrypt |
418 | * directly into the target buffer. | |
419 | */ | |
17926a79 DH |
420 | nsg = skb_cow_data(skb, 0, &trailer); |
421 | if (nsg < 0) | |
422 | goto nomem; | |
423 | ||
424 | sg = _sg; | |
425 | if (unlikely(nsg > 4)) { | |
426 | sg = kmalloc(sizeof(*sg) * nsg, GFP_NOIO); | |
427 | if (!sg) | |
428 | goto nomem; | |
429 | } | |
430 | ||
68e3f5dd | 431 | sg_init_table(sg, nsg); |
248f219c | 432 | skb_to_sgvec(skb, sg, offset, len); |
17926a79 DH |
433 | |
434 | /* decrypt from the session key */ | |
19ffa01c | 435 | token = call->conn->params.key->payload.data[0]; |
33941284 | 436 | memcpy(&iv, token->kad->session_key, sizeof(iv)); |
17926a79 | 437 | |
1afe593b HX |
438 | skcipher_request_set_tfm(req, call->conn->cipher); |
439 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
248f219c | 440 | skcipher_request_set_crypt(req, sg, sg, len, iv.x); |
1afe593b HX |
441 | crypto_skcipher_decrypt(req); |
442 | skcipher_request_zero(req); | |
17926a79 DH |
443 | if (sg != _sg) |
444 | kfree(sg); | |
445 | ||
5a42976d | 446 | /* Extract the decrypted packet length */ |
248f219c | 447 | if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) { |
5a42976d DH |
448 | rxrpc_abort_call("XV2", call, seq, RXKADDATALEN, EPROTO); |
449 | goto protocol_error; | |
450 | } | |
248f219c DH |
451 | offset += sizeof(sechdr); |
452 | len -= sizeof(sechdr); | |
17926a79 DH |
453 | |
454 | buf = ntohl(sechdr.data_size); | |
455 | data_size = buf & 0xffff; | |
456 | ||
457 | check = buf >> 16; | |
5a42976d | 458 | check ^= seq ^ call->call_id; |
17926a79 DH |
459 | check &= 0xffff; |
460 | if (check != 0) { | |
5a42976d | 461 | rxrpc_abort_call("V2C", call, seq, RXKADSEALEDINCON, EPROTO); |
17926a79 DH |
462 | goto protocol_error; |
463 | } | |
464 | ||
248f219c | 465 | if (data_size > len) { |
5a42976d DH |
466 | rxrpc_abort_call("V2L", call, seq, RXKADDATALEN, EPROTO); |
467 | goto protocol_error; | |
468 | } | |
17926a79 DH |
469 | |
470 | _leave(" = 0 [dlen=%x]", data_size); | |
471 | return 0; | |
472 | ||
17926a79 | 473 | protocol_error: |
26cb02aa | 474 | rxrpc_send_abort_packet(call); |
17926a79 DH |
475 | _leave(" = -EPROTO"); |
476 | return -EPROTO; | |
477 | ||
478 | nomem: | |
479 | _leave(" = -ENOMEM"); | |
480 | return -ENOMEM; | |
481 | } | |
482 | ||
483 | /* | |
5a42976d DH |
484 | * Verify the security on a received packet or subpacket (if part of a |
485 | * jumbo packet). | |
17926a79 | 486 | */ |
5a42976d | 487 | static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb, |
248f219c | 488 | unsigned int offset, unsigned int len, |
5a42976d | 489 | rxrpc_seq_t seq, u16 expected_cksum) |
17926a79 | 490 | { |
1afe593b | 491 | SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher); |
17926a79 | 492 | struct rxrpc_crypt iv; |
a263629d | 493 | struct scatterlist sg; |
0d12f8a4 DH |
494 | u16 cksum; |
495 | u32 x, y; | |
17926a79 DH |
496 | |
497 | _enter("{%d{%x}},{#%u}", | |
5a42976d | 498 | call->debug_id, key_serial(call->conn->params.key), seq); |
17926a79 DH |
499 | |
500 | if (!call->conn->cipher) | |
501 | return 0; | |
502 | ||
17926a79 DH |
503 | /* continue encrypting from where we left off */ |
504 | memcpy(&iv, call->conn->csum_iv.x, sizeof(iv)); | |
17926a79 DH |
505 | |
506 | /* validate the security checksum */ | |
01a90a45 | 507 | x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT); |
5a42976d | 508 | x |= seq & 0x3fffffff; |
a263629d HX |
509 | call->crypto_buf[0] = htonl(call->call_id); |
510 | call->crypto_buf[1] = htonl(x); | |
1afe593b | 511 | |
a263629d | 512 | sg_init_one(&sg, call->crypto_buf, 8); |
1afe593b HX |
513 | skcipher_request_set_tfm(req, call->conn->cipher); |
514 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
a263629d | 515 | skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x); |
1afe593b HX |
516 | crypto_skcipher_encrypt(req); |
517 | skcipher_request_zero(req); | |
17926a79 | 518 | |
a263629d | 519 | y = ntohl(call->crypto_buf[1]); |
0d12f8a4 DH |
520 | cksum = (y >> 16) & 0xffff; |
521 | if (cksum == 0) | |
522 | cksum = 1; /* zero checksums are not permitted */ | |
17926a79 | 523 | |
5a42976d DH |
524 | if (cksum != expected_cksum) { |
525 | rxrpc_abort_call("VCK", call, seq, RXKADSEALEDINCON, EPROTO); | |
26cb02aa | 526 | rxrpc_send_abort_packet(call); |
17926a79 DH |
527 | _leave(" = -EPROTO [csum failed]"); |
528 | return -EPROTO; | |
529 | } | |
530 | ||
19ffa01c | 531 | switch (call->conn->params.security_level) { |
17926a79 | 532 | case RXRPC_SECURITY_PLAIN: |
5a42976d | 533 | return 0; |
17926a79 | 534 | case RXRPC_SECURITY_AUTH: |
248f219c | 535 | return rxkad_verify_packet_1(call, skb, offset, len, seq); |
17926a79 | 536 | case RXRPC_SECURITY_ENCRYPT: |
248f219c | 537 | return rxkad_verify_packet_2(call, skb, offset, len, seq); |
17926a79 | 538 | default: |
5a42976d | 539 | return -ENOANO; |
17926a79 | 540 | } |
17926a79 DH |
541 | } |
542 | ||
248f219c DH |
543 | /* |
544 | * Locate the data contained in a packet that was partially encrypted. | |
545 | */ | |
546 | static void rxkad_locate_data_1(struct rxrpc_call *call, struct sk_buff *skb, | |
547 | unsigned int *_offset, unsigned int *_len) | |
548 | { | |
549 | struct rxkad_level1_hdr sechdr; | |
550 | ||
551 | if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0) | |
552 | BUG(); | |
553 | *_offset += sizeof(sechdr); | |
554 | *_len = ntohl(sechdr.data_size) & 0xffff; | |
555 | } | |
556 | ||
557 | /* | |
558 | * Locate the data contained in a packet that was completely encrypted. | |
559 | */ | |
560 | static void rxkad_locate_data_2(struct rxrpc_call *call, struct sk_buff *skb, | |
561 | unsigned int *_offset, unsigned int *_len) | |
562 | { | |
563 | struct rxkad_level2_hdr sechdr; | |
564 | ||
565 | if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0) | |
566 | BUG(); | |
567 | *_offset += sizeof(sechdr); | |
568 | *_len = ntohl(sechdr.data_size) & 0xffff; | |
569 | } | |
570 | ||
571 | /* | |
572 | * Locate the data contained in an already decrypted packet. | |
573 | */ | |
574 | static void rxkad_locate_data(struct rxrpc_call *call, struct sk_buff *skb, | |
575 | unsigned int *_offset, unsigned int *_len) | |
576 | { | |
577 | switch (call->conn->params.security_level) { | |
578 | case RXRPC_SECURITY_AUTH: | |
579 | rxkad_locate_data_1(call, skb, _offset, _len); | |
580 | return; | |
581 | case RXRPC_SECURITY_ENCRYPT: | |
582 | rxkad_locate_data_2(call, skb, _offset, _len); | |
583 | return; | |
584 | default: | |
585 | return; | |
586 | } | |
587 | } | |
588 | ||
17926a79 DH |
589 | /* |
590 | * issue a challenge | |
591 | */ | |
592 | static int rxkad_issue_challenge(struct rxrpc_connection *conn) | |
593 | { | |
594 | struct rxkad_challenge challenge; | |
0d12f8a4 | 595 | struct rxrpc_wire_header whdr; |
17926a79 DH |
596 | struct msghdr msg; |
597 | struct kvec iov[2]; | |
598 | size_t len; | |
0d12f8a4 | 599 | u32 serial; |
17926a79 DH |
600 | int ret; |
601 | ||
19ffa01c | 602 | _enter("{%d,%x}", conn->debug_id, key_serial(conn->params.key)); |
17926a79 | 603 | |
19ffa01c | 604 | ret = key_validate(conn->params.key); |
17926a79 DH |
605 | if (ret < 0) |
606 | return ret; | |
607 | ||
608 | get_random_bytes(&conn->security_nonce, sizeof(conn->security_nonce)); | |
609 | ||
610 | challenge.version = htonl(2); | |
611 | challenge.nonce = htonl(conn->security_nonce); | |
612 | challenge.min_level = htonl(0); | |
613 | challenge.__padding = 0; | |
614 | ||
85f32278 DH |
615 | msg.msg_name = &conn->params.peer->srx.transport.sin; |
616 | msg.msg_namelen = sizeof(conn->params.peer->srx.transport.sin); | |
17926a79 DH |
617 | msg.msg_control = NULL; |
618 | msg.msg_controllen = 0; | |
619 | msg.msg_flags = 0; | |
620 | ||
19ffa01c DH |
621 | whdr.epoch = htonl(conn->proto.epoch); |
622 | whdr.cid = htonl(conn->proto.cid); | |
0d12f8a4 DH |
623 | whdr.callNumber = 0; |
624 | whdr.seq = 0; | |
625 | whdr.type = RXRPC_PACKET_TYPE_CHALLENGE; | |
626 | whdr.flags = conn->out_clientflag; | |
627 | whdr.userStatus = 0; | |
628 | whdr.securityIndex = conn->security_ix; | |
629 | whdr._rsvd = 0; | |
19ffa01c | 630 | whdr.serviceId = htons(conn->params.service_id); |
0d12f8a4 DH |
631 | |
632 | iov[0].iov_base = &whdr; | |
633 | iov[0].iov_len = sizeof(whdr); | |
17926a79 DH |
634 | iov[1].iov_base = &challenge; |
635 | iov[1].iov_len = sizeof(challenge); | |
636 | ||
637 | len = iov[0].iov_len + iov[1].iov_len; | |
638 | ||
0d12f8a4 DH |
639 | serial = atomic_inc_return(&conn->serial); |
640 | whdr.serial = htonl(serial); | |
641 | _proto("Tx CHALLENGE %%%u", serial); | |
17926a79 | 642 | |
85f32278 | 643 | ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len); |
17926a79 DH |
644 | if (ret < 0) { |
645 | _debug("sendmsg failed: %d", ret); | |
646 | return -EAGAIN; | |
647 | } | |
648 | ||
649 | _leave(" = 0"); | |
650 | return 0; | |
651 | } | |
652 | ||
653 | /* | |
654 | * send a Kerberos security response | |
655 | */ | |
656 | static int rxkad_send_response(struct rxrpc_connection *conn, | |
0d12f8a4 | 657 | struct rxrpc_host_header *hdr, |
17926a79 DH |
658 | struct rxkad_response *resp, |
659 | const struct rxkad_key *s2) | |
660 | { | |
0d12f8a4 | 661 | struct rxrpc_wire_header whdr; |
17926a79 DH |
662 | struct msghdr msg; |
663 | struct kvec iov[3]; | |
664 | size_t len; | |
0d12f8a4 | 665 | u32 serial; |
17926a79 DH |
666 | int ret; |
667 | ||
668 | _enter(""); | |
669 | ||
85f32278 DH |
670 | msg.msg_name = &conn->params.peer->srx.transport.sin; |
671 | msg.msg_namelen = sizeof(conn->params.peer->srx.transport.sin); | |
17926a79 DH |
672 | msg.msg_control = NULL; |
673 | msg.msg_controllen = 0; | |
674 | msg.msg_flags = 0; | |
675 | ||
0d12f8a4 DH |
676 | memset(&whdr, 0, sizeof(whdr)); |
677 | whdr.epoch = htonl(hdr->epoch); | |
678 | whdr.cid = htonl(hdr->cid); | |
679 | whdr.type = RXRPC_PACKET_TYPE_RESPONSE; | |
680 | whdr.flags = conn->out_clientflag; | |
681 | whdr.securityIndex = hdr->securityIndex; | |
682 | whdr.serviceId = htons(hdr->serviceId); | |
17926a79 | 683 | |
0d12f8a4 DH |
684 | iov[0].iov_base = &whdr; |
685 | iov[0].iov_len = sizeof(whdr); | |
17926a79 DH |
686 | iov[1].iov_base = resp; |
687 | iov[1].iov_len = sizeof(*resp); | |
0d12f8a4 | 688 | iov[2].iov_base = (void *)s2->ticket; |
17926a79 DH |
689 | iov[2].iov_len = s2->ticket_len; |
690 | ||
691 | len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len; | |
692 | ||
0d12f8a4 DH |
693 | serial = atomic_inc_return(&conn->serial); |
694 | whdr.serial = htonl(serial); | |
695 | _proto("Tx RESPONSE %%%u", serial); | |
17926a79 | 696 | |
85f32278 | 697 | ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 3, len); |
17926a79 DH |
698 | if (ret < 0) { |
699 | _debug("sendmsg failed: %d", ret); | |
700 | return -EAGAIN; | |
701 | } | |
702 | ||
703 | _leave(" = 0"); | |
704 | return 0; | |
705 | } | |
706 | ||
707 | /* | |
708 | * calculate the response checksum | |
709 | */ | |
710 | static void rxkad_calc_response_checksum(struct rxkad_response *response) | |
711 | { | |
712 | u32 csum = 1000003; | |
713 | int loop; | |
714 | u8 *p = (u8 *) response; | |
715 | ||
716 | for (loop = sizeof(*response); loop > 0; loop--) | |
717 | csum = csum * 0x10204081 + *p++; | |
718 | ||
719 | response->encrypted.checksum = htonl(csum); | |
720 | } | |
721 | ||
17926a79 DH |
722 | /* |
723 | * encrypt the response packet | |
724 | */ | |
725 | static void rxkad_encrypt_response(struct rxrpc_connection *conn, | |
726 | struct rxkad_response *resp, | |
727 | const struct rxkad_key *s2) | |
728 | { | |
1afe593b | 729 | SKCIPHER_REQUEST_ON_STACK(req, conn->cipher); |
17926a79 | 730 | struct rxrpc_crypt iv; |
a263629d | 731 | struct scatterlist sg[1]; |
17926a79 DH |
732 | |
733 | /* continue encrypting from where we left off */ | |
734 | memcpy(&iv, s2->session_key, sizeof(iv)); | |
17926a79 | 735 | |
a263629d HX |
736 | sg_init_table(sg, 1); |
737 | sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted)); | |
1afe593b HX |
738 | skcipher_request_set_tfm(req, conn->cipher); |
739 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
740 | skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x); | |
1afe593b HX |
741 | crypto_skcipher_encrypt(req); |
742 | skcipher_request_zero(req); | |
17926a79 DH |
743 | } |
744 | ||
745 | /* | |
746 | * respond to a challenge packet | |
747 | */ | |
748 | static int rxkad_respond_to_challenge(struct rxrpc_connection *conn, | |
749 | struct sk_buff *skb, | |
750 | u32 *_abort_code) | |
751 | { | |
33941284 | 752 | const struct rxrpc_key_token *token; |
17926a79 DH |
753 | struct rxkad_challenge challenge; |
754 | struct rxkad_response resp | |
755 | __attribute__((aligned(8))); /* must be aligned for crypto */ | |
248f219c | 756 | struct rxrpc_skb_priv *sp = rxrpc_skb(skb); |
17926a79 DH |
757 | u32 version, nonce, min_level, abort_code; |
758 | int ret; | |
759 | ||
19ffa01c | 760 | _enter("{%d,%x}", conn->debug_id, key_serial(conn->params.key)); |
17926a79 | 761 | |
19ffa01c | 762 | if (!conn->params.key) { |
17926a79 DH |
763 | _leave(" = -EPROTO [no key]"); |
764 | return -EPROTO; | |
765 | } | |
766 | ||
19ffa01c | 767 | ret = key_validate(conn->params.key); |
17926a79 DH |
768 | if (ret < 0) { |
769 | *_abort_code = RXKADEXPIRED; | |
770 | return ret; | |
771 | } | |
772 | ||
773 | abort_code = RXKADPACKETSHORT; | |
775e5b71 DH |
774 | if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header), |
775 | &challenge, sizeof(challenge)) < 0) | |
17926a79 DH |
776 | goto protocol_error; |
777 | ||
778 | version = ntohl(challenge.version); | |
779 | nonce = ntohl(challenge.nonce); | |
780 | min_level = ntohl(challenge.min_level); | |
781 | ||
782 | _proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }", | |
0d12f8a4 | 783 | sp->hdr.serial, version, nonce, min_level); |
17926a79 DH |
784 | |
785 | abort_code = RXKADINCONSISTENCY; | |
786 | if (version != RXKAD_VERSION) | |
787 | goto protocol_error; | |
788 | ||
789 | abort_code = RXKADLEVELFAIL; | |
19ffa01c | 790 | if (conn->params.security_level < min_level) |
17926a79 DH |
791 | goto protocol_error; |
792 | ||
19ffa01c | 793 | token = conn->params.key->payload.data[0]; |
17926a79 DH |
794 | |
795 | /* build the response packet */ | |
796 | memset(&resp, 0, sizeof(resp)); | |
797 | ||
098a2099 | 798 | resp.version = htonl(RXKAD_VERSION); |
19ffa01c DH |
799 | resp.encrypted.epoch = htonl(conn->proto.epoch); |
800 | resp.encrypted.cid = htonl(conn->proto.cid); | |
098a2099 DH |
801 | resp.encrypted.securityIndex = htonl(conn->security_ix); |
802 | resp.encrypted.inc_nonce = htonl(nonce + 1); | |
19ffa01c | 803 | resp.encrypted.level = htonl(conn->params.security_level); |
098a2099 DH |
804 | resp.kvno = htonl(token->kad->kvno); |
805 | resp.ticket_len = htonl(token->kad->ticket_len); | |
806 | ||
a1399f8b DH |
807 | resp.encrypted.call_id[0] = htonl(conn->channels[0].call_counter); |
808 | resp.encrypted.call_id[1] = htonl(conn->channels[1].call_counter); | |
809 | resp.encrypted.call_id[2] = htonl(conn->channels[2].call_counter); | |
810 | resp.encrypted.call_id[3] = htonl(conn->channels[3].call_counter); | |
17926a79 DH |
811 | |
812 | /* calculate the response checksum and then do the encryption */ | |
813 | rxkad_calc_response_checksum(&resp); | |
33941284 DH |
814 | rxkad_encrypt_response(conn, &resp, token->kad); |
815 | return rxkad_send_response(conn, &sp->hdr, &resp, token->kad); | |
17926a79 DH |
816 | |
817 | protocol_error: | |
818 | *_abort_code = abort_code; | |
819 | _leave(" = -EPROTO [%d]", abort_code); | |
820 | return -EPROTO; | |
821 | } | |
822 | ||
823 | /* | |
824 | * decrypt the kerberos IV ticket in the response | |
825 | */ | |
826 | static int rxkad_decrypt_ticket(struct rxrpc_connection *conn, | |
827 | void *ticket, size_t ticket_len, | |
828 | struct rxrpc_crypt *_session_key, | |
829 | time_t *_expiry, | |
830 | u32 *_abort_code) | |
831 | { | |
1afe593b | 832 | struct skcipher_request *req; |
17926a79 | 833 | struct rxrpc_crypt iv, key; |
68e3f5dd | 834 | struct scatterlist sg[1]; |
17926a79 | 835 | struct in_addr addr; |
95c96174 | 836 | unsigned int life; |
17926a79 DH |
837 | time_t issue, now; |
838 | bool little_endian; | |
839 | int ret; | |
840 | u8 *p, *q, *name, *end; | |
841 | ||
842 | _enter("{%d},{%x}", conn->debug_id, key_serial(conn->server_key)); | |
843 | ||
844 | *_expiry = 0; | |
845 | ||
846 | ret = key_validate(conn->server_key); | |
847 | if (ret < 0) { | |
848 | switch (ret) { | |
849 | case -EKEYEXPIRED: | |
850 | *_abort_code = RXKADEXPIRED; | |
851 | goto error; | |
852 | default: | |
853 | *_abort_code = RXKADNOAUTH; | |
854 | goto error; | |
855 | } | |
856 | } | |
857 | ||
146aa8b1 | 858 | ASSERT(conn->server_key->payload.data[0] != NULL); |
17926a79 DH |
859 | ASSERTCMP((unsigned long) ticket & 7UL, ==, 0); |
860 | ||
146aa8b1 | 861 | memcpy(&iv, &conn->server_key->payload.data[2], sizeof(iv)); |
17926a79 | 862 | |
1afe593b HX |
863 | req = skcipher_request_alloc(conn->server_key->payload.data[0], |
864 | GFP_NOFS); | |
865 | if (!req) { | |
866 | *_abort_code = RXKADNOAUTH; | |
867 | ret = -ENOMEM; | |
868 | goto error; | |
869 | } | |
17926a79 | 870 | |
68e3f5dd | 871 | sg_init_one(&sg[0], ticket, ticket_len); |
1afe593b HX |
872 | skcipher_request_set_callback(req, 0, NULL, NULL); |
873 | skcipher_request_set_crypt(req, sg, sg, ticket_len, iv.x); | |
1afe593b HX |
874 | crypto_skcipher_decrypt(req); |
875 | skcipher_request_free(req); | |
17926a79 DH |
876 | |
877 | p = ticket; | |
878 | end = p + ticket_len; | |
879 | ||
880 | #define Z(size) \ | |
881 | ({ \ | |
882 | u8 *__str = p; \ | |
883 | q = memchr(p, 0, end - p); \ | |
884 | if (!q || q - p > (size)) \ | |
885 | goto bad_ticket; \ | |
886 | for (; p < q; p++) \ | |
887 | if (!isprint(*p)) \ | |
888 | goto bad_ticket; \ | |
889 | p++; \ | |
890 | __str; \ | |
891 | }) | |
892 | ||
893 | /* extract the ticket flags */ | |
894 | _debug("KIV FLAGS: %x", *p); | |
895 | little_endian = *p & 1; | |
896 | p++; | |
897 | ||
898 | /* extract the authentication name */ | |
899 | name = Z(ANAME_SZ); | |
900 | _debug("KIV ANAME: %s", name); | |
901 | ||
902 | /* extract the principal's instance */ | |
903 | name = Z(INST_SZ); | |
904 | _debug("KIV INST : %s", name); | |
905 | ||
906 | /* extract the principal's authentication domain */ | |
907 | name = Z(REALM_SZ); | |
908 | _debug("KIV REALM: %s", name); | |
909 | ||
910 | if (end - p < 4 + 8 + 4 + 2) | |
911 | goto bad_ticket; | |
912 | ||
913 | /* get the IPv4 address of the entity that requested the ticket */ | |
914 | memcpy(&addr, p, sizeof(addr)); | |
915 | p += 4; | |
21454aaa | 916 | _debug("KIV ADDR : %pI4", &addr); |
17926a79 DH |
917 | |
918 | /* get the session key from the ticket */ | |
919 | memcpy(&key, p, sizeof(key)); | |
920 | p += 8; | |
921 | _debug("KIV KEY : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1])); | |
922 | memcpy(_session_key, &key, sizeof(key)); | |
923 | ||
924 | /* get the ticket's lifetime */ | |
925 | life = *p++ * 5 * 60; | |
926 | _debug("KIV LIFE : %u", life); | |
927 | ||
928 | /* get the issue time of the ticket */ | |
929 | if (little_endian) { | |
930 | __le32 stamp; | |
931 | memcpy(&stamp, p, 4); | |
932 | issue = le32_to_cpu(stamp); | |
933 | } else { | |
934 | __be32 stamp; | |
935 | memcpy(&stamp, p, 4); | |
936 | issue = be32_to_cpu(stamp); | |
937 | } | |
938 | p += 4; | |
2c6b47de | 939 | now = get_seconds(); |
17926a79 DH |
940 | _debug("KIV ISSUE: %lx [%lx]", issue, now); |
941 | ||
942 | /* check the ticket is in date */ | |
943 | if (issue > now) { | |
944 | *_abort_code = RXKADNOAUTH; | |
945 | ret = -EKEYREJECTED; | |
946 | goto error; | |
947 | } | |
948 | ||
949 | if (issue < now - life) { | |
950 | *_abort_code = RXKADEXPIRED; | |
951 | ret = -EKEYEXPIRED; | |
952 | goto error; | |
953 | } | |
954 | ||
955 | *_expiry = issue + life; | |
956 | ||
957 | /* get the service name */ | |
958 | name = Z(SNAME_SZ); | |
959 | _debug("KIV SNAME: %s", name); | |
960 | ||
961 | /* get the service instance name */ | |
962 | name = Z(INST_SZ); | |
963 | _debug("KIV SINST: %s", name); | |
964 | ||
965 | ret = 0; | |
966 | error: | |
967 | _leave(" = %d", ret); | |
968 | return ret; | |
969 | ||
970 | bad_ticket: | |
971 | *_abort_code = RXKADBADTICKET; | |
972 | ret = -EBADMSG; | |
973 | goto error; | |
974 | } | |
975 | ||
976 | /* | |
977 | * decrypt the response packet | |
978 | */ | |
979 | static void rxkad_decrypt_response(struct rxrpc_connection *conn, | |
980 | struct rxkad_response *resp, | |
981 | const struct rxrpc_crypt *session_key) | |
982 | { | |
1afe593b | 983 | SKCIPHER_REQUEST_ON_STACK(req, rxkad_ci); |
a263629d | 984 | struct scatterlist sg[1]; |
17926a79 DH |
985 | struct rxrpc_crypt iv; |
986 | ||
987 | _enter(",,%08x%08x", | |
988 | ntohl(session_key->n[0]), ntohl(session_key->n[1])); | |
989 | ||
990 | ASSERT(rxkad_ci != NULL); | |
991 | ||
992 | mutex_lock(&rxkad_ci_mutex); | |
1afe593b HX |
993 | if (crypto_skcipher_setkey(rxkad_ci, session_key->x, |
994 | sizeof(*session_key)) < 0) | |
17926a79 DH |
995 | BUG(); |
996 | ||
997 | memcpy(&iv, session_key, sizeof(iv)); | |
17926a79 | 998 | |
a263629d HX |
999 | sg_init_table(sg, 1); |
1000 | sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted)); | |
1afe593b HX |
1001 | skcipher_request_set_tfm(req, rxkad_ci); |
1002 | skcipher_request_set_callback(req, 0, NULL, NULL); | |
1003 | skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x); | |
1afe593b HX |
1004 | crypto_skcipher_decrypt(req); |
1005 | skcipher_request_zero(req); | |
1006 | ||
17926a79 DH |
1007 | mutex_unlock(&rxkad_ci_mutex); |
1008 | ||
1009 | _leave(""); | |
1010 | } | |
1011 | ||
1012 | /* | |
1013 | * verify a response | |
1014 | */ | |
1015 | static int rxkad_verify_response(struct rxrpc_connection *conn, | |
1016 | struct sk_buff *skb, | |
1017 | u32 *_abort_code) | |
1018 | { | |
1019 | struct rxkad_response response | |
1020 | __attribute__((aligned(8))); /* must be aligned for crypto */ | |
248f219c | 1021 | struct rxrpc_skb_priv *sp = rxrpc_skb(skb); |
17926a79 DH |
1022 | struct rxrpc_crypt session_key; |
1023 | time_t expiry; | |
1024 | void *ticket; | |
91e916cf AV |
1025 | u32 abort_code, version, kvno, ticket_len, level; |
1026 | __be32 csum; | |
a1399f8b | 1027 | int ret, i; |
17926a79 DH |
1028 | |
1029 | _enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key)); | |
1030 | ||
1031 | abort_code = RXKADPACKETSHORT; | |
775e5b71 DH |
1032 | if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header), |
1033 | &response, sizeof(response)) < 0) | |
17926a79 DH |
1034 | goto protocol_error; |
1035 | if (!pskb_pull(skb, sizeof(response))) | |
1036 | BUG(); | |
1037 | ||
1038 | version = ntohl(response.version); | |
1039 | ticket_len = ntohl(response.ticket_len); | |
1040 | kvno = ntohl(response.kvno); | |
17926a79 | 1041 | _proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }", |
0d12f8a4 | 1042 | sp->hdr.serial, version, kvno, ticket_len); |
17926a79 DH |
1043 | |
1044 | abort_code = RXKADINCONSISTENCY; | |
1045 | if (version != RXKAD_VERSION) | |
4aa9cb32 | 1046 | goto protocol_error; |
17926a79 DH |
1047 | |
1048 | abort_code = RXKADTICKETLEN; | |
1049 | if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN) | |
1050 | goto protocol_error; | |
1051 | ||
1052 | abort_code = RXKADUNKNOWNKEY; | |
1053 | if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5) | |
1054 | goto protocol_error; | |
1055 | ||
1056 | /* extract the kerberos ticket and decrypt and decode it */ | |
1057 | ticket = kmalloc(ticket_len, GFP_NOFS); | |
1058 | if (!ticket) | |
1059 | return -ENOMEM; | |
1060 | ||
1061 | abort_code = RXKADPACKETSHORT; | |
775e5b71 DH |
1062 | if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header), |
1063 | ticket, ticket_len) < 0) | |
17926a79 DH |
1064 | goto protocol_error_free; |
1065 | ||
1066 | ret = rxkad_decrypt_ticket(conn, ticket, ticket_len, &session_key, | |
1067 | &expiry, &abort_code); | |
1068 | if (ret < 0) { | |
1069 | *_abort_code = abort_code; | |
1070 | kfree(ticket); | |
1071 | return ret; | |
1072 | } | |
1073 | ||
1074 | /* use the session key from inside the ticket to decrypt the | |
1075 | * response */ | |
1076 | rxkad_decrypt_response(conn, &response, &session_key); | |
1077 | ||
1078 | abort_code = RXKADSEALEDINCON; | |
19ffa01c | 1079 | if (ntohl(response.encrypted.epoch) != conn->proto.epoch) |
17926a79 | 1080 | goto protocol_error_free; |
19ffa01c | 1081 | if (ntohl(response.encrypted.cid) != conn->proto.cid) |
17926a79 DH |
1082 | goto protocol_error_free; |
1083 | if (ntohl(response.encrypted.securityIndex) != conn->security_ix) | |
1084 | goto protocol_error_free; | |
1085 | csum = response.encrypted.checksum; | |
1086 | response.encrypted.checksum = 0; | |
1087 | rxkad_calc_response_checksum(&response); | |
1088 | if (response.encrypted.checksum != csum) | |
1089 | goto protocol_error_free; | |
1090 | ||
a1399f8b DH |
1091 | spin_lock(&conn->channel_lock); |
1092 | for (i = 0; i < RXRPC_MAXCALLS; i++) { | |
1093 | struct rxrpc_call *call; | |
1094 | u32 call_id = ntohl(response.encrypted.call_id[i]); | |
1095 | ||
1096 | if (call_id > INT_MAX) | |
1097 | goto protocol_error_unlock; | |
1098 | ||
1099 | if (call_id < conn->channels[i].call_counter) | |
1100 | goto protocol_error_unlock; | |
1101 | if (call_id > conn->channels[i].call_counter) { | |
1102 | call = rcu_dereference_protected( | |
1103 | conn->channels[i].call, | |
1104 | lockdep_is_held(&conn->channel_lock)); | |
1105 | if (call && call->state < RXRPC_CALL_COMPLETE) | |
1106 | goto protocol_error_unlock; | |
1107 | conn->channels[i].call_counter = call_id; | |
1108 | } | |
1109 | } | |
1110 | spin_unlock(&conn->channel_lock); | |
17926a79 DH |
1111 | |
1112 | abort_code = RXKADOUTOFSEQUENCE; | |
0d12f8a4 | 1113 | if (ntohl(response.encrypted.inc_nonce) != conn->security_nonce + 1) |
17926a79 DH |
1114 | goto protocol_error_free; |
1115 | ||
1116 | abort_code = RXKADLEVELFAIL; | |
1117 | level = ntohl(response.encrypted.level); | |
1118 | if (level > RXRPC_SECURITY_ENCRYPT) | |
1119 | goto protocol_error_free; | |
19ffa01c | 1120 | conn->params.security_level = level; |
17926a79 DH |
1121 | |
1122 | /* create a key to hold the security data and expiration time - after | |
1123 | * this the connection security can be handled in exactly the same way | |
1124 | * as for a client connection */ | |
1125 | ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno); | |
1126 | if (ret < 0) { | |
1127 | kfree(ticket); | |
1128 | return ret; | |
1129 | } | |
1130 | ||
1131 | kfree(ticket); | |
1132 | _leave(" = 0"); | |
1133 | return 0; | |
1134 | ||
a1399f8b DH |
1135 | protocol_error_unlock: |
1136 | spin_unlock(&conn->channel_lock); | |
17926a79 DH |
1137 | protocol_error_free: |
1138 | kfree(ticket); | |
1139 | protocol_error: | |
1140 | *_abort_code = abort_code; | |
1141 | _leave(" = -EPROTO [%d]", abort_code); | |
1142 | return -EPROTO; | |
1143 | } | |
1144 | ||
1145 | /* | |
1146 | * clear the connection security | |
1147 | */ | |
1148 | static void rxkad_clear(struct rxrpc_connection *conn) | |
1149 | { | |
1150 | _enter(""); | |
1151 | ||
1152 | if (conn->cipher) | |
1afe593b | 1153 | crypto_free_skcipher(conn->cipher); |
17926a79 DH |
1154 | } |
1155 | ||
648af7fc DH |
1156 | /* |
1157 | * Initialise the rxkad security service. | |
1158 | */ | |
1159 | static int rxkad_init(void) | |
1160 | { | |
1161 | /* pin the cipher we need so that the crypto layer doesn't invoke | |
1162 | * keventd to go get it */ | |
1163 | rxkad_ci = crypto_alloc_skcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC); | |
fa54cc70 | 1164 | return PTR_ERR_OR_ZERO(rxkad_ci); |
648af7fc DH |
1165 | } |
1166 | ||
1167 | /* | |
1168 | * Clean up the rxkad security service. | |
1169 | */ | |
1170 | static void rxkad_exit(void) | |
1171 | { | |
1172 | if (rxkad_ci) | |
1173 | crypto_free_skcipher(rxkad_ci); | |
1174 | } | |
1175 | ||
17926a79 DH |
1176 | /* |
1177 | * RxRPC Kerberos-based security | |
1178 | */ | |
648af7fc | 1179 | const struct rxrpc_security rxkad = { |
17926a79 | 1180 | .name = "rxkad", |
8b815477 | 1181 | .security_index = RXRPC_SECURITY_RXKAD, |
648af7fc DH |
1182 | .init = rxkad_init, |
1183 | .exit = rxkad_exit, | |
17926a79 DH |
1184 | .init_connection_security = rxkad_init_connection_security, |
1185 | .prime_packet_security = rxkad_prime_packet_security, | |
1186 | .secure_packet = rxkad_secure_packet, | |
1187 | .verify_packet = rxkad_verify_packet, | |
248f219c | 1188 | .locate_data = rxkad_locate_data, |
17926a79 DH |
1189 | .issue_challenge = rxkad_issue_challenge, |
1190 | .respond_to_challenge = rxkad_respond_to_challenge, | |
1191 | .verify_response = rxkad_verify_response, | |
1192 | .clear = rxkad_clear, | |
1193 | }; |