]> git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - net/netfilter/nf_conntrack_ftp.c
projects / mirror_ubuntu-bionic-kernel.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
netfilter: nf_defrag_ipv6.o included twice
[mirror_ubuntu-bionic-kernel.git] / net / netfilter / nf_conntrack_ftp.c
1 /* FTP extension for connection tracking. */
2
3 /* (C) 1999-2001 Paul `Rusty' Russell
4 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
5 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
6 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13 #include <linux/module.h>
14 #include <linux/moduleparam.h>
15 #include <linux/netfilter.h>
16 #include <linux/ip.h>
17 #include <linux/slab.h>
18 #include <linux/ipv6.h>
19 #include <linux/ctype.h>
20 #include <linux/inet.h>
21 #include <net/checksum.h>
22 #include <net/tcp.h>
23
24 #include <net/netfilter/nf_conntrack.h>
25 #include <net/netfilter/nf_conntrack_expect.h>
26 #include <net/netfilter/nf_conntrack_ecache.h>
27 #include <net/netfilter/nf_conntrack_helper.h>
28 #include <linux/netfilter/nf_conntrack_ftp.h>
29
30 MODULE_LICENSE("GPL");
31 MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
32 MODULE_DESCRIPTION("ftp connection tracking helper");
33 MODULE_ALIAS("ip_conntrack_ftp");
34 MODULE_ALIAS_NFCT_HELPER("ftp");
35
36 /* This is slow, but it's simple. --RR */
37 static char *ftp_buffer;
38
39 static DEFINE_SPINLOCK(nf_ftp_lock);
40
41 #define MAX_PORTS 8
42 static u_int16_t ports[MAX_PORTS];
43 static unsigned int ports_c;
44 module_param_array(ports, ushort, &ports_c, 0400);
45
46 static bool loose;
47 module_param(loose, bool, 0600);
48
49 unsigned int (*nf_nat_ftp_hook)(struct sk_buff *skb,
50 enum ip_conntrack_info ctinfo,
51 enum nf_ct_ftp_type type,
52 unsigned int protoff,
53 unsigned int matchoff,
54 unsigned int matchlen,
55 struct nf_conntrack_expect *exp);
56 EXPORT_SYMBOL_GPL(nf_nat_ftp_hook);
57
58 static int try_rfc959(const char *, size_t, struct nf_conntrack_man *,
59 char, unsigned int *);
60 static int try_rfc1123(const char *, size_t, struct nf_conntrack_man *,
61 char, unsigned int *);
62 static int try_eprt(const char *, size_t, struct nf_conntrack_man *,
63 char, unsigned int *);
64 static int try_epsv_response(const char *, size_t, struct nf_conntrack_man *,
65 char, unsigned int *);
66
67 static struct ftp_search {
68 const char *pattern;
69 size_t plen;
70 char skip;
71 char term;
72 enum nf_ct_ftp_type ftptype;
73 int (*getnum)(const char *, size_t, struct nf_conntrack_man *, char, unsigned int *);
74 } search[IP_CT_DIR_MAX][2] = {
75 [IP_CT_DIR_ORIGINAL] = {
76 {
77 .pattern = "PORT",
78 .plen = sizeof("PORT") - 1,
79 .skip = ' ',
80 .term = '\r',
81 .ftptype = NF_CT_FTP_PORT,
82 .getnum = try_rfc959,
83 },
84 {
85 .pattern = "EPRT",
86 .plen = sizeof("EPRT") - 1,
87 .skip = ' ',
88 .term = '\r',
89 .ftptype = NF_CT_FTP_EPRT,
90 .getnum = try_eprt,
91 },
92 },
93 [IP_CT_DIR_REPLY] = {
94 {
95 .pattern = "227 ",
96 .plen = sizeof("227 ") - 1,
97 .ftptype = NF_CT_FTP_PASV,
98 .getnum = try_rfc1123,
99 },
100 {
101 .pattern = "229 ",
102 .plen = sizeof("229 ") - 1,
103 .skip = '(',
104 .term = ')',
105 .ftptype = NF_CT_FTP_EPSV,
106 .getnum = try_epsv_response,
107 },
108 },
109 };
110
111 static int
112 get_ipv6_addr(const char *src, size_t dlen, struct in6_addr *dst, u_int8_t term)
113 {
114 const char *end;
115 int ret = in6_pton(src, min_t(size_t, dlen, 0xffff), (u8 *)dst, term, &end);
116 if (ret > 0)
117 return (int)(end - src);
118 return 0;
119 }
120
121 static int try_number(const char *data, size_t dlen, u_int32_t array[],
122 int array_size, char sep, char term)
123 {
124 u_int32_t i, len;
125
126 memset(array, 0, sizeof(array[0])*array_size);
127
128 /* Keep data pointing at next char. */
129 for (i = 0, len = 0; len < dlen && i < array_size; len++, data++) {
130 if (*data >= '0' && *data <= '9') {
131 array[i] = array[i]*10 + *data - '0';
132 }
133 else if (*data == sep)
134 i++;
135 else {
136 /* Unexpected character; true if it's the
137 terminator (or we don't care about one)
138 and we're finished. */
139 if ((*data == term || !term) && i == array_size - 1)
140 return len;
141
142 pr_debug("Char %u (got %u nums) `%u' unexpected\n",
143 len, i, *data);
144 return 0;
145 }
146 }
147 pr_debug("Failed to fill %u numbers separated by %c\n",
148 array_size, sep);
149 return 0;
150 }
151
152 /* Returns 0, or length of numbers: 192,168,1,1,5,6 */
153 static int try_rfc959(const char *data, size_t dlen,
154 struct nf_conntrack_man *cmd, char term,
155 unsigned int *offset)
156 {
157 int length;
158 u_int32_t array[6];
159
160 length = try_number(data, dlen, array, 6, ',', term);
161 if (length == 0)
162 return 0;
163
164 cmd->u3.ip = htonl((array[0] << 24) | (array[1] << 16) |
165 (array[2] << 8) | array[3]);
166 cmd->u.tcp.port = htons((array[4] << 8) | array[5]);
167 return length;
168 }
169
170 /*
171 * From RFC 1123:
172 * The format of the 227 reply to a PASV command is not
173 * well standardized. In particular, an FTP client cannot
174 * assume that the parentheses shown on page 40 of RFC-959
175 * will be present (and in fact, Figure 3 on page 43 omits
176 * them). Therefore, a User-FTP program that interprets
177 * the PASV reply must scan the reply for the first digit
178 * of the host and port numbers.
179 */
180 static int try_rfc1123(const char *data, size_t dlen,
181 struct nf_conntrack_man *cmd, char term,
182 unsigned int *offset)
183 {
184 int i;
185 for (i = 0; i < dlen; i++)
186 if (isdigit(data[i]))
187 break;
188
189 if (i == dlen)
190 return 0;
191
192 *offset += i;
193
194 return try_rfc959(data + i, dlen - i, cmd, 0, offset);
195 }
196
197 /* Grab port: number up to delimiter */
198 static int get_port(const char *data, int start, size_t dlen, char delim,
199 __be16 *port)
200 {
201 u_int16_t tmp_port = 0;
202 int i;
203
204 for (i = start; i < dlen; i++) {
205 /* Finished? */
206 if (data[i] == delim) {
207 if (tmp_port == 0)
208 break;
209 *port = htons(tmp_port);
210 pr_debug("get_port: return %d\n", tmp_port);
211 return i + 1;
212 }
213 else if (data[i] >= '0' && data[i] <= '9')
214 tmp_port = tmp_port*10 + data[i] - '0';
215 else { /* Some other crap */
216 pr_debug("get_port: invalid char.\n");
217 break;
218 }
219 }
220 return 0;
221 }
222
223 /* Returns 0, or length of numbers: |1|132.235.1.2|6275| or |2|3ffe::1|6275| */
224 static int try_eprt(const char *data, size_t dlen, struct nf_conntrack_man *cmd,
225 char term, unsigned int *offset)
226 {
227 char delim;
228 int length;
229
230 /* First character is delimiter, then "1" for IPv4 or "2" for IPv6,
231 then delimiter again. */
232 if (dlen <= 3) {
233 pr_debug("EPRT: too short\n");
234 return 0;
235 }
236 delim = data[0];
237 if (isdigit(delim) || delim < 33 || delim > 126 || data[2] != delim) {
238 pr_debug("try_eprt: invalid delimitter.\n");
239 return 0;
240 }
241
242 if ((cmd->l3num == PF_INET && data[1] != '1') ||
243 (cmd->l3num == PF_INET6 && data[1] != '2')) {
244 pr_debug("EPRT: invalid protocol number.\n");
245 return 0;
246 }
247
248 pr_debug("EPRT: Got %c%c%c\n", delim, data[1], delim);
249
250 if (data[1] == '1') {
251 u_int32_t array[4];
252
253 /* Now we have IP address. */
254 length = try_number(data + 3, dlen - 3, array, 4, '.', delim);
255 if (length != 0)
256 cmd->u3.ip = htonl((array[0] << 24) | (array[1] << 16)
257 | (array[2] << 8) | array[3]);
258 } else {
259 /* Now we have IPv6 address. */
260 length = get_ipv6_addr(data + 3, dlen - 3,
261 (struct in6_addr *)cmd->u3.ip6, delim);
262 }
263
264 if (length == 0)
265 return 0;
266 pr_debug("EPRT: Got IP address!\n");
267 /* Start offset includes initial "|1|", and trailing delimiter */
268 return get_port(data, 3 + length + 1, dlen, delim, &cmd->u.tcp.port);
269 }
270
271 /* Returns 0, or length of numbers: |||6446| */
272 static int try_epsv_response(const char *data, size_t dlen,
273 struct nf_conntrack_man *cmd, char term,
274 unsigned int *offset)
275 {
276 char delim;
277
278 /* Three delimiters. */
279 if (dlen <= 3) return 0;
280 delim = data[0];
281 if (isdigit(delim) || delim < 33 || delim > 126 ||
282 data[1] != delim || data[2] != delim)
283 return 0;
284
285 return get_port(data, 3, dlen, delim, &cmd->u.tcp.port);
286 }
287
288 /* Return 1 for match, 0 for accept, -1 for partial. */
289 static int find_pattern(const char *data, size_t dlen,
290 const char *pattern, size_t plen,
291 char skip, char term,
292 unsigned int *numoff,
293 unsigned int *numlen,
294 struct nf_conntrack_man *cmd,
295 int (*getnum)(const char *, size_t,
296 struct nf_conntrack_man *, char,
297 unsigned int *))
298 {
299 size_t i = plen;
300
301 pr_debug("find_pattern `%s': dlen = %Zu\n", pattern, dlen);
302 if (dlen == 0)
303 return 0;
304
305 if (dlen <= plen) {
306 /* Short packet: try for partial? */
307 if (strnicmp(data, pattern, dlen) == 0)
308 return -1;
309 else return 0;
310 }
311
312 if (strnicmp(data, pattern, plen) != 0) {
313 #if 0
314 size_t i;
315
316 pr_debug("ftp: string mismatch\n");
317 for (i = 0; i < plen; i++) {
318 pr_debug("ftp:char %u `%c'(%u) vs `%c'(%u)\n",
319 i, data[i], data[i],
320 pattern[i], pattern[i]);
321 }
322 #endif
323 return 0;
324 }
325
326 pr_debug("Pattern matches!\n");
327 /* Now we've found the constant string, try to skip
328 to the 'skip' character */
329 if (skip) {
330 for (i = plen; data[i] != skip; i++)
331 if (i == dlen - 1) return -1;
332
333 /* Skip over the last character */
334 i++;
335 }
336
337 pr_debug("Skipped up to `%c'!\n", skip);
338
339 *numoff = i;
340 *numlen = getnum(data + i, dlen - i, cmd, term, numoff);
341 if (!*numlen)
342 return -1;
343
344 pr_debug("Match succeeded!\n");
345 return 1;
346 }
347
348 /* Look up to see if we're just after a \n. */
349 static int find_nl_seq(u32 seq, const struct nf_ct_ftp_master *info, int dir)
350 {
351 unsigned int i;
352
353 for (i = 0; i < info->seq_aft_nl_num[dir]; i++)
354 if (info->seq_aft_nl[dir][i] == seq)
355 return 1;
356 return 0;
357 }
358
359 /* We don't update if it's older than what we have. */
360 static void update_nl_seq(struct nf_conn *ct, u32 nl_seq,
361 struct nf_ct_ftp_master *info, int dir,
362 struct sk_buff *skb)
363 {
364 unsigned int i, oldest;
365
366 /* Look for oldest: if we find exact match, we're done. */
367 for (i = 0; i < info->seq_aft_nl_num[dir]; i++) {
368 if (info->seq_aft_nl[dir][i] == nl_seq)
369 return;
370 }
371
372 if (info->seq_aft_nl_num[dir] < NUM_SEQ_TO_REMEMBER) {
373 info->seq_aft_nl[dir][info->seq_aft_nl_num[dir]++] = nl_seq;
374 } else {
375 if (before(info->seq_aft_nl[dir][0], info->seq_aft_nl[dir][1]))
376 oldest = 0;
377 else
378 oldest = 1;
379
380 if (after(nl_seq, info->seq_aft_nl[dir][oldest]))
381 info->seq_aft_nl[dir][oldest] = nl_seq;
382 }
383 }
384
385 static int help(struct sk_buff *skb,
386 unsigned int protoff,
387 struct nf_conn *ct,
388 enum ip_conntrack_info ctinfo)
389 {
390 unsigned int dataoff, datalen;
391 const struct tcphdr *th;
392 struct tcphdr _tcph;
393 const char *fb_ptr;
394 int ret;
395 u32 seq;
396 int dir = CTINFO2DIR(ctinfo);
397 unsigned int uninitialized_var(matchlen), uninitialized_var(matchoff);
398 struct nf_ct_ftp_master *ct_ftp_info = nfct_help_data(ct);
399 struct nf_conntrack_expect *exp;
400 union nf_inet_addr *daddr;
401 struct nf_conntrack_man cmd = {};
402 unsigned int i;
403 int found = 0, ends_in_nl;
404 typeof(nf_nat_ftp_hook) nf_nat_ftp;
405
406 /* Until there's been traffic both ways, don't look in packets. */
407 if (ctinfo != IP_CT_ESTABLISHED &&
408 ctinfo != IP_CT_ESTABLISHED_REPLY) {
409 pr_debug("ftp: Conntrackinfo = %u\n", ctinfo);
410 return NF_ACCEPT;
411 }
412
413 th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph);
414 if (th == NULL)
415 return NF_ACCEPT;
416
417 dataoff = protoff + th->doff * 4;
418 /* No data? */
419 if (dataoff >= skb->len) {
420 pr_debug("ftp: dataoff(%u) >= skblen(%u)\n", dataoff,
421 skb->len);
422 return NF_ACCEPT;
423 }
424 datalen = skb->len - dataoff;
425
426 spin_lock_bh(&nf_ftp_lock);
427 fb_ptr = skb_header_pointer(skb, dataoff, datalen, ftp_buffer);
428 BUG_ON(fb_ptr == NULL);
429
430 ends_in_nl = (fb_ptr[datalen - 1] == '\n');
431 seq = ntohl(th->seq) + datalen;
432
433 /* Look up to see if we're just after a \n. */
434 if (!find_nl_seq(ntohl(th->seq), ct_ftp_info, dir)) {
435 /* We're picking up this, clear flags and let it continue */
436 if (unlikely(ct_ftp_info->flags[dir] & NF_CT_FTP_SEQ_PICKUP)) {
437 ct_ftp_info->flags[dir] ^= NF_CT_FTP_SEQ_PICKUP;
438 goto skip_nl_seq;
439 }
440
441 /* Now if this ends in \n, update ftp info. */
442 pr_debug("nf_conntrack_ftp: wrong seq pos %s(%u) or %s(%u)\n",
443 ct_ftp_info->seq_aft_nl_num[dir] > 0 ? "" : "(UNSET)",
444 ct_ftp_info->seq_aft_nl[dir][0],
445 ct_ftp_info->seq_aft_nl_num[dir] > 1 ? "" : "(UNSET)",
446 ct_ftp_info->seq_aft_nl[dir][1]);
447 ret = NF_ACCEPT;
448 goto out_update_nl;
449 }
450
451 skip_nl_seq:
452 /* Initialize IP/IPv6 addr to expected address (it's not mentioned
453 in EPSV responses) */
454 cmd.l3num = nf_ct_l3num(ct);
455 memcpy(cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
456 sizeof(cmd.u3.all));
457
458 for (i = 0; i < ARRAY_SIZE(search[dir]); i++) {
459 found = find_pattern(fb_ptr, datalen,
460 search[dir][i].pattern,
461 search[dir][i].plen,
462 search[dir][i].skip,
463 search[dir][i].term,
464 &matchoff, &matchlen,
465 &cmd,
466 search[dir][i].getnum);
467 if (found) break;
468 }
469 if (found == -1) {
470 /* We don't usually drop packets. After all, this is
471 connection tracking, not packet filtering.
472 However, it is necessary for accurate tracking in
473 this case. */
474 nf_ct_helper_log(skb, ct, "partial matching of `%s'",
475 search[dir][i].pattern);
476 ret = NF_DROP;
477 goto out;
478 } else if (found == 0) { /* No match */
479 ret = NF_ACCEPT;
480 goto out_update_nl;
481 }
482
483 pr_debug("conntrack_ftp: match `%.*s' (%u bytes at %u)\n",
484 matchlen, fb_ptr + matchoff,
485 matchlen, ntohl(th->seq) + matchoff);
486
487 exp = nf_ct_expect_alloc(ct);
488 if (exp == NULL) {
489 nf_ct_helper_log(skb, ct, "cannot alloc expectation");
490 ret = NF_DROP;
491 goto out;
492 }
493
494 /* We refer to the reverse direction ("!dir") tuples here,
495 * because we're expecting something in the other direction.
496 * Doesn't matter unless NAT is happening. */
497 daddr = &ct->tuplehash[!dir].tuple.dst.u3;
498
499 /* Update the ftp info */
500 if ((cmd.l3num == nf_ct_l3num(ct)) &&
501 memcmp(&cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
502 sizeof(cmd.u3.all))) {
503 /* Enrico Scholz's passive FTP to partially RNAT'd ftp
504 server: it really wants us to connect to a
505 different IP address. Simply don't record it for
506 NAT. */
507 if (cmd.l3num == PF_INET) {
508 pr_debug("conntrack_ftp: NOT RECORDING: %pI4 != %pI4\n",
509 &cmd.u3.ip,
510 &ct->tuplehash[dir].tuple.src.u3.ip);
511 } else {
512 pr_debug("conntrack_ftp: NOT RECORDING: %pI6 != %pI6\n",
513 cmd.u3.ip6,
514 ct->tuplehash[dir].tuple.src.u3.ip6);
515 }
516
517 /* Thanks to Cristiano Lincoln Mattos
518 <lincoln@cesar.org.br> for reporting this potential
519 problem (DMZ machines opening holes to internal
520 networks, or the packet filter itself). */
521 if (!loose) {
522 ret = NF_ACCEPT;
523 goto out_put_expect;
524 }
525 daddr = &cmd.u3;
526 }
527
528 nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, cmd.l3num,
529 &ct->tuplehash[!dir].tuple.src.u3, daddr,
530 IPPROTO_TCP, NULL, &cmd.u.tcp.port);
531
532 /* Now, NAT might want to mangle the packet, and register the
533 * (possibly changed) expectation itself. */
534 nf_nat_ftp = rcu_dereference(nf_nat_ftp_hook);
535 if (nf_nat_ftp && ct->status & IPS_NAT_MASK)
536 ret = nf_nat_ftp(skb, ctinfo, search[dir][i].ftptype,
537 protoff, matchoff, matchlen, exp);
538 else {
539 /* Can't expect this? Best to drop packet now. */
540 if (nf_ct_expect_related(exp) != 0) {
541 nf_ct_helper_log(skb, ct, "cannot add expectation");
542 ret = NF_DROP;
543 } else
544 ret = NF_ACCEPT;
545 }
546
547 out_put_expect:
548 nf_ct_expect_put(exp);
549
550 out_update_nl:
551 /* Now if this ends in \n, update ftp info. Seq may have been
552 * adjusted by NAT code. */
553 if (ends_in_nl)
554 update_nl_seq(ct, seq, ct_ftp_info, dir, skb);
555 out:
556 spin_unlock_bh(&nf_ftp_lock);
557 return ret;
558 }
559
560 static int nf_ct_ftp_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
561 {
562 struct nf_ct_ftp_master *ftp = nfct_help_data(ct);
563
564 /* This conntrack has been injected from user-space, always pick up
565 * sequence tracking. Otherwise, the first FTP command after the
566 * failover breaks.
567 */
568 ftp->flags[IP_CT_DIR_ORIGINAL] |= NF_CT_FTP_SEQ_PICKUP;
569 ftp->flags[IP_CT_DIR_REPLY] |= NF_CT_FTP_SEQ_PICKUP;
570 return 0;
571 }
572
573 static struct nf_conntrack_helper ftp[MAX_PORTS][2] __read_mostly;
574
575 static const struct nf_conntrack_expect_policy ftp_exp_policy = {
576 .max_expected = 1,
577 .timeout = 5 * 60,
578 };
579
580 /* don't make this __exit, since it's called from __init ! */
581 static void nf_conntrack_ftp_fini(void)
582 {
583 int i, j;
584 for (i = 0; i < ports_c; i++) {
585 for (j = 0; j < 2; j++) {
586 if (ftp[i][j].me == NULL)
587 continue;
588
589 pr_debug("nf_ct_ftp: unregistering helper for pf: %d "
590 "port: %d\n",
591 ftp[i][j].tuple.src.l3num, ports[i]);
592 nf_conntrack_helper_unregister(&ftp[i][j]);
593 }
594 }
595
596 kfree(ftp_buffer);
597 }
598
599 static int __init nf_conntrack_ftp_init(void)
600 {
601 int i, j = -1, ret = 0;
602
603 ftp_buffer = kmalloc(65536, GFP_KERNEL);
604 if (!ftp_buffer)
605 return -ENOMEM;
606
607 if (ports_c == 0)
608 ports[ports_c++] = FTP_PORT;
609
610 /* FIXME should be configurable whether IPv4 and IPv6 FTP connections
611 are tracked or not - YK */
612 for (i = 0; i < ports_c; i++) {
613 ftp[i][0].tuple.src.l3num = PF_INET;
614 ftp[i][1].tuple.src.l3num = PF_INET6;
615 for (j = 0; j < 2; j++) {
616 ftp[i][j].data_len = sizeof(struct nf_ct_ftp_master);
617 ftp[i][j].tuple.src.u.tcp.port = htons(ports[i]);
618 ftp[i][j].tuple.dst.protonum = IPPROTO_TCP;
619 ftp[i][j].expect_policy = &ftp_exp_policy;
620 ftp[i][j].me = THIS_MODULE;
621 ftp[i][j].help = help;
622 ftp[i][j].from_nlattr = nf_ct_ftp_from_nlattr;
623 if (ports[i] == FTP_PORT)
624 sprintf(ftp[i][j].name, "ftp");
625 else
626 sprintf(ftp[i][j].name, "ftp-%d", ports[i]);
627
628 pr_debug("nf_ct_ftp: registering helper for pf: %d "
629 "port: %d\n",
630 ftp[i][j].tuple.src.l3num, ports[i]);
631 ret = nf_conntrack_helper_register(&ftp[i][j]);
632 if (ret) {
633 printk(KERN_ERR "nf_ct_ftp: failed to register"
634 " helper for pf: %d port: %d\n",
635 ftp[i][j].tuple.src.l3num, ports[i]);
636 nf_conntrack_ftp_fini();
637 return ret;
638 }
639 }
640 }
641
642 return 0;
643 }
644
645 module_init(nf_conntrack_ftp_init);
646 module_exit(nf_conntrack_ftp_fini);
ubuntu-bionic-kernel mirror