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c618db2a | 1 | // SPDX-License-Identifier: GPL-2.0-only |
84c61fe1 | 2 | /* Copyright (c) 2016 Tom Herbert <tom@herbertland.com> */ |
c618db2a JK |
3 | |
4 | #include <linux/skbuff.h> | |
84c61fe1 JK |
5 | #include <linux/workqueue.h> |
6 | #include <net/strparser.h> | |
7 | #include <net/tcp.h> | |
8 | #include <net/sock.h> | |
9 | #include <net/tls.h> | |
c618db2a JK |
10 | |
11 | #include "tls.h" | |
12 | ||
84c61fe1 JK |
13 | static struct workqueue_struct *tls_strp_wq; |
14 | ||
15 | static void tls_strp_abort_strp(struct tls_strparser *strp, int err) | |
16 | { | |
17 | if (strp->stopped) | |
18 | return; | |
19 | ||
20 | strp->stopped = 1; | |
21 | ||
22 | /* Report an error on the lower socket */ | |
23 | strp->sk->sk_err = -err; | |
24 | sk_error_report(strp->sk); | |
25 | } | |
26 | ||
27 | static void tls_strp_anchor_free(struct tls_strparser *strp) | |
d4e5db64 | 28 | { |
84c61fe1 JK |
29 | struct skb_shared_info *shinfo = skb_shinfo(strp->anchor); |
30 | ||
31 | DEBUG_NET_WARN_ON_ONCE(atomic_read(&shinfo->dataref) != 1); | |
32 | shinfo->frag_list = NULL; | |
33 | consume_skb(strp->anchor); | |
34 | strp->anchor = NULL; | |
35 | } | |
36 | ||
37 | /* Create a new skb with the contents of input copied to its page frags */ | |
38 | static struct sk_buff *tls_strp_msg_make_copy(struct tls_strparser *strp) | |
39 | { | |
40 | struct strp_msg *rxm; | |
d4e5db64 | 41 | struct sk_buff *skb; |
84c61fe1 JK |
42 | int i, err, offset; |
43 | ||
d800a7b3 | 44 | skb = alloc_skb_with_frags(0, strp->stm.full_len, TLS_PAGE_ORDER, |
84c61fe1 JK |
45 | &err, strp->sk->sk_allocation); |
46 | if (!skb) | |
47 | return NULL; | |
48 | ||
49 | offset = strp->stm.offset; | |
50 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { | |
51 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; | |
d4e5db64 | 52 | |
84c61fe1 JK |
53 | WARN_ON_ONCE(skb_copy_bits(strp->anchor, offset, |
54 | skb_frag_address(frag), | |
55 | skb_frag_size(frag))); | |
56 | offset += skb_frag_size(frag); | |
57 | } | |
58 | ||
210620ae JK |
59 | skb->len = strp->stm.full_len; |
60 | skb->data_len = strp->stm.full_len; | |
84c61fe1 JK |
61 | skb_copy_header(skb, strp->anchor); |
62 | rxm = strp_msg(skb); | |
63 | rxm->offset = 0; | |
d4e5db64 JK |
64 | return skb; |
65 | } | |
66 | ||
84c61fe1 JK |
67 | /* Steal the input skb, input msg is invalid after calling this function */ |
68 | struct sk_buff *tls_strp_msg_detach(struct tls_sw_context_rx *ctx) | |
69 | { | |
70 | struct tls_strparser *strp = &ctx->strp; | |
71 | ||
72 | #ifdef CONFIG_TLS_DEVICE | |
73 | DEBUG_NET_WARN_ON_ONCE(!strp->anchor->decrypted); | |
74 | #else | |
75 | /* This function turns an input into an output, | |
76 | * that can only happen if we have offload. | |
77 | */ | |
78 | WARN_ON(1); | |
79 | #endif | |
80 | ||
81 | if (strp->copy_mode) { | |
82 | struct sk_buff *skb; | |
83 | ||
84 | /* Replace anchor with an empty skb, this is a little | |
85 | * dangerous but __tls_cur_msg() warns on empty skbs | |
86 | * so hopefully we'll catch abuses. | |
87 | */ | |
88 | skb = alloc_skb(0, strp->sk->sk_allocation); | |
89 | if (!skb) | |
90 | return NULL; | |
91 | ||
92 | swap(strp->anchor, skb); | |
93 | return skb; | |
94 | } | |
95 | ||
96 | return tls_strp_msg_make_copy(strp); | |
97 | } | |
98 | ||
99 | /* Force the input skb to be in copy mode. The data ownership remains | |
100 | * with the input skb itself (meaning unpause will wipe it) but it can | |
101 | * be modified. | |
102 | */ | |
8b3c59a7 JK |
103 | int tls_strp_msg_cow(struct tls_sw_context_rx *ctx) |
104 | { | |
84c61fe1 JK |
105 | struct tls_strparser *strp = &ctx->strp; |
106 | struct sk_buff *skb; | |
107 | ||
108 | if (strp->copy_mode) | |
109 | return 0; | |
110 | ||
111 | skb = tls_strp_msg_make_copy(strp); | |
112 | if (!skb) | |
113 | return -ENOMEM; | |
114 | ||
115 | tls_strp_anchor_free(strp); | |
116 | strp->anchor = skb; | |
117 | ||
118 | tcp_read_done(strp->sk, strp->stm.full_len); | |
119 | strp->copy_mode = 1; | |
120 | ||
121 | return 0; | |
122 | } | |
123 | ||
124 | /* Make a clone (in the skb sense) of the input msg to keep a reference | |
125 | * to the underlying data. The reference-holding skbs get placed on | |
126 | * @dst. | |
127 | */ | |
128 | int tls_strp_msg_hold(struct tls_strparser *strp, struct sk_buff_head *dst) | |
129 | { | |
130 | struct skb_shared_info *shinfo = skb_shinfo(strp->anchor); | |
131 | ||
132 | if (strp->copy_mode) { | |
133 | struct sk_buff *skb; | |
134 | ||
135 | WARN_ON_ONCE(!shinfo->nr_frags); | |
136 | ||
137 | /* We can't skb_clone() the anchor, it gets wiped by unpause */ | |
138 | skb = alloc_skb(0, strp->sk->sk_allocation); | |
139 | if (!skb) | |
140 | return -ENOMEM; | |
141 | ||
142 | __skb_queue_tail(dst, strp->anchor); | |
143 | strp->anchor = skb; | |
144 | } else { | |
145 | struct sk_buff *iter, *clone; | |
146 | int chunk, len, offset; | |
147 | ||
148 | offset = strp->stm.offset; | |
149 | len = strp->stm.full_len; | |
150 | iter = shinfo->frag_list; | |
151 | ||
152 | while (len > 0) { | |
153 | if (iter->len <= offset) { | |
154 | offset -= iter->len; | |
155 | goto next; | |
156 | } | |
157 | ||
158 | chunk = iter->len - offset; | |
159 | offset = 0; | |
160 | ||
161 | clone = skb_clone(iter, strp->sk->sk_allocation); | |
162 | if (!clone) | |
163 | return -ENOMEM; | |
164 | __skb_queue_tail(dst, clone); | |
165 | ||
166 | len -= chunk; | |
167 | next: | |
168 | iter = iter->next; | |
169 | } | |
170 | } | |
171 | ||
172 | return 0; | |
173 | } | |
174 | ||
175 | static void tls_strp_flush_anchor_copy(struct tls_strparser *strp) | |
176 | { | |
177 | struct skb_shared_info *shinfo = skb_shinfo(strp->anchor); | |
178 | int i; | |
179 | ||
180 | DEBUG_NET_WARN_ON_ONCE(atomic_read(&shinfo->dataref) != 1); | |
181 | ||
182 | for (i = 0; i < shinfo->nr_frags; i++) | |
183 | __skb_frag_unref(&shinfo->frags[i], false); | |
184 | shinfo->nr_frags = 0; | |
185 | strp->copy_mode = 0; | |
186 | } | |
187 | ||
188 | static int tls_strp_copyin(read_descriptor_t *desc, struct sk_buff *in_skb, | |
189 | unsigned int offset, size_t in_len) | |
190 | { | |
191 | struct tls_strparser *strp = (struct tls_strparser *)desc->arg.data; | |
84c61fe1 JK |
192 | struct sk_buff *skb; |
193 | skb_frag_t *frag; | |
8fd1e151 YL |
194 | size_t len, chunk; |
195 | int sz; | |
84c61fe1 JK |
196 | |
197 | if (strp->msg_ready) | |
198 | return 0; | |
199 | ||
200 | skb = strp->anchor; | |
201 | frag = &skb_shinfo(skb)->frags[skb->len / PAGE_SIZE]; | |
202 | ||
203 | len = in_len; | |
204 | /* First make sure we got the header */ | |
205 | if (!strp->stm.full_len) { | |
206 | /* Assume one page is more than enough for headers */ | |
207 | chunk = min_t(size_t, len, PAGE_SIZE - skb_frag_size(frag)); | |
208 | WARN_ON_ONCE(skb_copy_bits(in_skb, offset, | |
209 | skb_frag_address(frag) + | |
210 | skb_frag_size(frag), | |
211 | chunk)); | |
212 | ||
213 | sz = tls_rx_msg_size(strp, strp->anchor); | |
214 | if (sz < 0) { | |
215 | desc->error = sz; | |
216 | return 0; | |
217 | } | |
218 | ||
219 | /* We may have over-read, sz == 0 is guaranteed under-read */ | |
220 | if (sz > 0) | |
221 | chunk = min_t(size_t, chunk, sz - skb->len); | |
222 | ||
223 | skb->len += chunk; | |
224 | skb->data_len += chunk; | |
225 | skb_frag_size_add(frag, chunk); | |
226 | frag++; | |
227 | len -= chunk; | |
228 | offset += chunk; | |
229 | ||
230 | strp->stm.full_len = sz; | |
231 | if (!strp->stm.full_len) | |
232 | goto read_done; | |
233 | } | |
234 | ||
235 | /* Load up more data */ | |
236 | while (len && strp->stm.full_len > skb->len) { | |
237 | chunk = min_t(size_t, len, strp->stm.full_len - skb->len); | |
238 | chunk = min_t(size_t, chunk, PAGE_SIZE - skb_frag_size(frag)); | |
239 | WARN_ON_ONCE(skb_copy_bits(in_skb, offset, | |
240 | skb_frag_address(frag) + | |
241 | skb_frag_size(frag), | |
242 | chunk)); | |
243 | ||
244 | skb->len += chunk; | |
245 | skb->data_len += chunk; | |
246 | skb_frag_size_add(frag, chunk); | |
247 | frag++; | |
248 | len -= chunk; | |
249 | offset += chunk; | |
250 | } | |
251 | ||
252 | if (strp->stm.full_len == skb->len) { | |
253 | desc->count = 0; | |
254 | ||
255 | strp->msg_ready = 1; | |
256 | tls_rx_msg_ready(strp); | |
257 | } | |
258 | ||
259 | read_done: | |
260 | return in_len - len; | |
261 | } | |
262 | ||
263 | static int tls_strp_read_copyin(struct tls_strparser *strp) | |
264 | { | |
265 | struct socket *sock = strp->sk->sk_socket; | |
266 | read_descriptor_t desc; | |
267 | ||
268 | desc.arg.data = strp; | |
269 | desc.error = 0; | |
270 | desc.count = 1; /* give more than one skb per call */ | |
271 | ||
272 | /* sk should be locked here, so okay to do read_sock */ | |
273 | sock->ops->read_sock(strp->sk, &desc, tls_strp_copyin); | |
274 | ||
275 | return desc.error; | |
276 | } | |
277 | ||
0d87bbd3 | 278 | static int tls_strp_read_copy(struct tls_strparser *strp, bool qshort) |
84c61fe1 JK |
279 | { |
280 | struct skb_shared_info *shinfo; | |
281 | struct page *page; | |
282 | int need_spc, len; | |
283 | ||
284 | /* If the rbuf is small or rcv window has collapsed to 0 we need | |
285 | * to read the data out. Otherwise the connection will stall. | |
286 | * Without pressure threshold of INT_MAX will never be ready. | |
287 | */ | |
0d87bbd3 | 288 | if (likely(qshort && !tcp_epollin_ready(strp->sk, INT_MAX))) |
84c61fe1 JK |
289 | return 0; |
290 | ||
291 | shinfo = skb_shinfo(strp->anchor); | |
292 | shinfo->frag_list = NULL; | |
293 | ||
294 | /* If we don't know the length go max plus page for cipher overhead */ | |
295 | need_spc = strp->stm.full_len ?: TLS_MAX_PAYLOAD_SIZE + PAGE_SIZE; | |
296 | ||
297 | for (len = need_spc; len > 0; len -= PAGE_SIZE) { | |
298 | page = alloc_page(strp->sk->sk_allocation); | |
299 | if (!page) { | |
300 | tls_strp_flush_anchor_copy(strp); | |
301 | return -ENOMEM; | |
302 | } | |
303 | ||
304 | skb_fill_page_desc(strp->anchor, shinfo->nr_frags++, | |
305 | page, 0, 0); | |
306 | } | |
307 | ||
308 | strp->copy_mode = 1; | |
309 | strp->stm.offset = 0; | |
310 | ||
311 | strp->anchor->len = 0; | |
312 | strp->anchor->data_len = 0; | |
313 | strp->anchor->truesize = round_up(need_spc, PAGE_SIZE); | |
314 | ||
315 | tls_strp_read_copyin(strp); | |
316 | ||
317 | return 0; | |
318 | } | |
319 | ||
0d87bbd3 JK |
320 | static bool tls_strp_check_no_dup(struct tls_strparser *strp) |
321 | { | |
322 | unsigned int len = strp->stm.offset + strp->stm.full_len; | |
323 | struct sk_buff *skb; | |
324 | u32 seq; | |
325 | ||
326 | skb = skb_shinfo(strp->anchor)->frag_list; | |
327 | seq = TCP_SKB_CB(skb)->seq; | |
328 | ||
329 | while (skb->len < len) { | |
330 | seq += skb->len; | |
331 | len -= skb->len; | |
332 | skb = skb->next; | |
333 | ||
334 | if (TCP_SKB_CB(skb)->seq != seq) | |
335 | return false; | |
336 | } | |
337 | ||
338 | return true; | |
339 | } | |
340 | ||
84c61fe1 JK |
341 | static void tls_strp_load_anchor_with_queue(struct tls_strparser *strp, int len) |
342 | { | |
343 | struct tcp_sock *tp = tcp_sk(strp->sk); | |
344 | struct sk_buff *first; | |
345 | u32 offset; | |
346 | ||
347 | first = tcp_recv_skb(strp->sk, tp->copied_seq, &offset); | |
348 | if (WARN_ON_ONCE(!first)) | |
349 | return; | |
350 | ||
351 | /* Bestow the state onto the anchor */ | |
352 | strp->anchor->len = offset + len; | |
353 | strp->anchor->data_len = offset + len; | |
354 | strp->anchor->truesize = offset + len; | |
355 | ||
356 | skb_shinfo(strp->anchor)->frag_list = first; | |
357 | ||
358 | skb_copy_header(strp->anchor, first); | |
359 | strp->anchor->destructor = NULL; | |
360 | ||
361 | strp->stm.offset = offset; | |
362 | } | |
363 | ||
364 | void tls_strp_msg_load(struct tls_strparser *strp, bool force_refresh) | |
365 | { | |
366 | struct strp_msg *rxm; | |
367 | struct tls_msg *tlm; | |
368 | ||
369 | DEBUG_NET_WARN_ON_ONCE(!strp->msg_ready); | |
370 | DEBUG_NET_WARN_ON_ONCE(!strp->stm.full_len); | |
371 | ||
372 | if (!strp->copy_mode && force_refresh) { | |
373 | if (WARN_ON(tcp_inq(strp->sk) < strp->stm.full_len)) | |
374 | return; | |
375 | ||
376 | tls_strp_load_anchor_with_queue(strp, strp->stm.full_len); | |
377 | } | |
378 | ||
379 | rxm = strp_msg(strp->anchor); | |
380 | rxm->full_len = strp->stm.full_len; | |
381 | rxm->offset = strp->stm.offset; | |
382 | tlm = tls_msg(strp->anchor); | |
383 | tlm->control = strp->mark; | |
384 | } | |
385 | ||
386 | /* Called with lock held on lower socket */ | |
387 | static int tls_strp_read_sock(struct tls_strparser *strp) | |
388 | { | |
389 | int sz, inq; | |
390 | ||
391 | inq = tcp_inq(strp->sk); | |
392 | if (inq < 1) | |
393 | return 0; | |
394 | ||
395 | if (unlikely(strp->copy_mode)) | |
396 | return tls_strp_read_copyin(strp); | |
397 | ||
398 | if (inq < strp->stm.full_len) | |
0d87bbd3 | 399 | return tls_strp_read_copy(strp, true); |
84c61fe1 JK |
400 | |
401 | if (!strp->stm.full_len) { | |
402 | tls_strp_load_anchor_with_queue(strp, inq); | |
403 | ||
404 | sz = tls_rx_msg_size(strp, strp->anchor); | |
405 | if (sz < 0) { | |
406 | tls_strp_abort_strp(strp, sz); | |
407 | return sz; | |
408 | } | |
409 | ||
410 | strp->stm.full_len = sz; | |
411 | ||
412 | if (!strp->stm.full_len || inq < strp->stm.full_len) | |
0d87bbd3 | 413 | return tls_strp_read_copy(strp, true); |
84c61fe1 JK |
414 | } |
415 | ||
0d87bbd3 JK |
416 | if (!tls_strp_check_no_dup(strp)) |
417 | return tls_strp_read_copy(strp, false); | |
418 | ||
84c61fe1 JK |
419 | strp->msg_ready = 1; |
420 | tls_rx_msg_ready(strp); | |
421 | ||
422 | return 0; | |
423 | } | |
424 | ||
425 | void tls_strp_check_rcv(struct tls_strparser *strp) | |
426 | { | |
427 | if (unlikely(strp->stopped) || strp->msg_ready) | |
428 | return; | |
429 | ||
430 | if (tls_strp_read_sock(strp) == -ENOMEM) | |
431 | queue_work(tls_strp_wq, &strp->work); | |
432 | } | |
433 | ||
434 | /* Lower sock lock held */ | |
435 | void tls_strp_data_ready(struct tls_strparser *strp) | |
436 | { | |
437 | /* This check is needed to synchronize with do_tls_strp_work. | |
438 | * do_tls_strp_work acquires a process lock (lock_sock) whereas | |
439 | * the lock held here is bh_lock_sock. The two locks can be | |
440 | * held by different threads at the same time, but bh_lock_sock | |
441 | * allows a thread in BH context to safely check if the process | |
442 | * lock is held. In this case, if the lock is held, queue work. | |
443 | */ | |
444 | if (sock_owned_by_user_nocheck(strp->sk)) { | |
445 | queue_work(tls_strp_wq, &strp->work); | |
446 | return; | |
447 | } | |
448 | ||
449 | tls_strp_check_rcv(strp); | |
450 | } | |
451 | ||
452 | static void tls_strp_work(struct work_struct *w) | |
453 | { | |
454 | struct tls_strparser *strp = | |
455 | container_of(w, struct tls_strparser, work); | |
456 | ||
457 | lock_sock(strp->sk); | |
458 | tls_strp_check_rcv(strp); | |
459 | release_sock(strp->sk); | |
460 | } | |
461 | ||
462 | void tls_strp_msg_done(struct tls_strparser *strp) | |
463 | { | |
464 | WARN_ON(!strp->stm.full_len); | |
465 | ||
466 | if (likely(!strp->copy_mode)) | |
467 | tcp_read_done(strp->sk, strp->stm.full_len); | |
468 | else | |
469 | tls_strp_flush_anchor_copy(strp); | |
470 | ||
471 | strp->msg_ready = 0; | |
472 | memset(&strp->stm, 0, sizeof(strp->stm)); | |
473 | ||
474 | tls_strp_check_rcv(strp); | |
475 | } | |
476 | ||
477 | void tls_strp_stop(struct tls_strparser *strp) | |
478 | { | |
479 | strp->stopped = 1; | |
480 | } | |
481 | ||
482 | int tls_strp_init(struct tls_strparser *strp, struct sock *sk) | |
483 | { | |
484 | memset(strp, 0, sizeof(*strp)); | |
485 | ||
486 | strp->sk = sk; | |
487 | ||
488 | strp->anchor = alloc_skb(0, GFP_KERNEL); | |
489 | if (!strp->anchor) | |
490 | return -ENOMEM; | |
491 | ||
492 | INIT_WORK(&strp->work, tls_strp_work); | |
8b3c59a7 | 493 | |
8b3c59a7 JK |
494 | return 0; |
495 | } | |
496 | ||
84c61fe1 JK |
497 | /* strp must already be stopped so that tls_strp_recv will no longer be called. |
498 | * Note that tls_strp_done is not called with the lower socket held. | |
499 | */ | |
500 | void tls_strp_done(struct tls_strparser *strp) | |
c618db2a | 501 | { |
84c61fe1 | 502 | WARN_ON(!strp->stopped); |
c618db2a | 503 | |
84c61fe1 JK |
504 | cancel_work_sync(&strp->work); |
505 | tls_strp_anchor_free(strp); | |
506 | } | |
507 | ||
508 | int __init tls_strp_dev_init(void) | |
509 | { | |
d11ef9cc | 510 | tls_strp_wq = create_workqueue("tls-strp"); |
84c61fe1 | 511 | if (unlikely(!tls_strp_wq)) |
c618db2a | 512 | return -ENOMEM; |
84c61fe1 | 513 | |
c618db2a JK |
514 | return 0; |
515 | } | |
84c61fe1 JK |
516 | |
517 | void tls_strp_dev_exit(void) | |
518 | { | |
519 | destroy_workqueue(tls_strp_wq); | |
520 | } |