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807467c2 PM |
1 | /* |
2 | * nf_nat_snmp_basic.c | |
3 | * | |
4 | * Basic SNMP Application Layer Gateway | |
5 | * | |
6 | * This IP NAT module is intended for use with SNMP network | |
7 | * discovery and monitoring applications where target networks use | |
8 | * conflicting private address realms. | |
9 | * | |
10 | * Static NAT is used to remap the networks from the view of the network | |
11 | * management system at the IP layer, and this module remaps some application | |
12 | * layer addresses to match. | |
13 | * | |
14 | * The simplest form of ALG is performed, where only tagged IP addresses | |
15 | * are modified. The module does not need to be MIB aware and only scans | |
16 | * messages at the ASN.1/BER level. | |
17 | * | |
18 | * Currently, only SNMPv1 and SNMPv2 are supported. | |
19 | * | |
20 | * More information on ALG and associated issues can be found in | |
21 | * RFC 2962 | |
22 | * | |
23 | * The ASB.1/BER parsing code is derived from the gxsnmp package by Gregory | |
24 | * McLean & Jochen Friedrich, stripped down for use in the kernel. | |
25 | * | |
26 | * Copyright (c) 2000 RP Internet (www.rpi.net.au). | |
27 | * | |
28 | * This program is free software; you can redistribute it and/or modify | |
29 | * it under the terms of the GNU General Public License as published by | |
30 | * the Free Software Foundation; either version 2 of the License, or | |
31 | * (at your option) any later version. | |
32 | * This program is distributed in the hope that it will be useful, | |
33 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
34 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
35 | * GNU General Public License for more details. | |
36 | * You should have received a copy of the GNU General Public License | |
37 | * along with this program; if not, write to the Free Software | |
38 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
39 | * | |
40 | * Author: James Morris <jmorris@intercode.com.au> | |
807467c2 PM |
41 | */ |
42 | #include <linux/module.h> | |
43 | #include <linux/moduleparam.h> | |
44 | #include <linux/types.h> | |
45 | #include <linux/kernel.h> | |
46 | #include <linux/in.h> | |
47 | #include <linux/ip.h> | |
48 | #include <linux/udp.h> | |
49 | #include <net/checksum.h> | |
50 | #include <net/udp.h> | |
51 | ||
52 | #include <net/netfilter/nf_nat.h> | |
6002f266 | 53 | #include <net/netfilter/nf_conntrack_expect.h> |
807467c2 PM |
54 | #include <net/netfilter/nf_conntrack_helper.h> |
55 | #include <net/netfilter/nf_nat_helper.h> | |
56 | ||
57 | MODULE_LICENSE("GPL"); | |
58 | MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); | |
59 | MODULE_DESCRIPTION("Basic SNMP Application Layer Gateway"); | |
60 | MODULE_ALIAS("ip_nat_snmp_basic"); | |
61 | ||
62 | #define SNMP_PORT 161 | |
63 | #define SNMP_TRAP_PORT 162 | |
e79ec50b | 64 | #define NOCT1(n) (*(u8 *)(n)) |
807467c2 PM |
65 | |
66 | static int debug; | |
67 | static DEFINE_SPINLOCK(snmp_lock); | |
68 | ||
69 | /* | |
70 | * Application layer address mapping mimics the NAT mapping, but | |
71 | * only for the first octet in this case (a more flexible system | |
72 | * can be implemented if needed). | |
73 | */ | |
74 | struct oct1_map | |
75 | { | |
76 | u_int8_t from; | |
77 | u_int8_t to; | |
78 | }; | |
79 | ||
80 | ||
81 | /***************************************************************************** | |
82 | * | |
83 | * Basic ASN.1 decoding routines (gxsnmp author Dirk Wisse) | |
84 | * | |
85 | *****************************************************************************/ | |
86 | ||
87 | /* Class */ | |
88 | #define ASN1_UNI 0 /* Universal */ | |
89 | #define ASN1_APL 1 /* Application */ | |
90 | #define ASN1_CTX 2 /* Context */ | |
91 | #define ASN1_PRV 3 /* Private */ | |
92 | ||
93 | /* Tag */ | |
94 | #define ASN1_EOC 0 /* End Of Contents */ | |
95 | #define ASN1_BOL 1 /* Boolean */ | |
96 | #define ASN1_INT 2 /* Integer */ | |
97 | #define ASN1_BTS 3 /* Bit String */ | |
98 | #define ASN1_OTS 4 /* Octet String */ | |
99 | #define ASN1_NUL 5 /* Null */ | |
100 | #define ASN1_OJI 6 /* Object Identifier */ | |
101 | #define ASN1_OJD 7 /* Object Description */ | |
102 | #define ASN1_EXT 8 /* External */ | |
103 | #define ASN1_SEQ 16 /* Sequence */ | |
104 | #define ASN1_SET 17 /* Set */ | |
105 | #define ASN1_NUMSTR 18 /* Numerical String */ | |
106 | #define ASN1_PRNSTR 19 /* Printable String */ | |
107 | #define ASN1_TEXSTR 20 /* Teletext String */ | |
108 | #define ASN1_VIDSTR 21 /* Video String */ | |
109 | #define ASN1_IA5STR 22 /* IA5 String */ | |
110 | #define ASN1_UNITIM 23 /* Universal Time */ | |
111 | #define ASN1_GENTIM 24 /* General Time */ | |
112 | #define ASN1_GRASTR 25 /* Graphical String */ | |
113 | #define ASN1_VISSTR 26 /* Visible String */ | |
114 | #define ASN1_GENSTR 27 /* General String */ | |
115 | ||
116 | /* Primitive / Constructed methods*/ | |
117 | #define ASN1_PRI 0 /* Primitive */ | |
118 | #define ASN1_CON 1 /* Constructed */ | |
119 | ||
120 | /* | |
121 | * Error codes. | |
122 | */ | |
123 | #define ASN1_ERR_NOERROR 0 | |
124 | #define ASN1_ERR_DEC_EMPTY 2 | |
125 | #define ASN1_ERR_DEC_EOC_MISMATCH 3 | |
126 | #define ASN1_ERR_DEC_LENGTH_MISMATCH 4 | |
127 | #define ASN1_ERR_DEC_BADVALUE 5 | |
128 | ||
129 | /* | |
130 | * ASN.1 context. | |
131 | */ | |
132 | struct asn1_ctx | |
133 | { | |
134 | int error; /* Error condition */ | |
135 | unsigned char *pointer; /* Octet just to be decoded */ | |
136 | unsigned char *begin; /* First octet */ | |
137 | unsigned char *end; /* Octet after last octet */ | |
138 | }; | |
139 | ||
140 | /* | |
141 | * Octet string (not null terminated) | |
142 | */ | |
143 | struct asn1_octstr | |
144 | { | |
145 | unsigned char *data; | |
146 | unsigned int len; | |
147 | }; | |
148 | ||
149 | static void asn1_open(struct asn1_ctx *ctx, | |
e905a9ed YH |
150 | unsigned char *buf, |
151 | unsigned int len) | |
807467c2 PM |
152 | { |
153 | ctx->begin = buf; | |
154 | ctx->end = buf + len; | |
155 | ctx->pointer = buf; | |
156 | ctx->error = ASN1_ERR_NOERROR; | |
157 | } | |
158 | ||
159 | static unsigned char asn1_octet_decode(struct asn1_ctx *ctx, unsigned char *ch) | |
160 | { | |
161 | if (ctx->pointer >= ctx->end) { | |
162 | ctx->error = ASN1_ERR_DEC_EMPTY; | |
163 | return 0; | |
164 | } | |
165 | *ch = *(ctx->pointer)++; | |
166 | return 1; | |
167 | } | |
168 | ||
169 | static unsigned char asn1_tag_decode(struct asn1_ctx *ctx, unsigned int *tag) | |
170 | { | |
171 | unsigned char ch; | |
172 | ||
173 | *tag = 0; | |
174 | ||
175 | do | |
176 | { | |
177 | if (!asn1_octet_decode(ctx, &ch)) | |
178 | return 0; | |
179 | *tag <<= 7; | |
180 | *tag |= ch & 0x7F; | |
181 | } while ((ch & 0x80) == 0x80); | |
182 | return 1; | |
183 | } | |
184 | ||
185 | static unsigned char asn1_id_decode(struct asn1_ctx *ctx, | |
e905a9ed YH |
186 | unsigned int *cls, |
187 | unsigned int *con, | |
188 | unsigned int *tag) | |
807467c2 PM |
189 | { |
190 | unsigned char ch; | |
191 | ||
192 | if (!asn1_octet_decode(ctx, &ch)) | |
193 | return 0; | |
194 | ||
195 | *cls = (ch & 0xC0) >> 6; | |
196 | *con = (ch & 0x20) >> 5; | |
197 | *tag = (ch & 0x1F); | |
198 | ||
199 | if (*tag == 0x1F) { | |
200 | if (!asn1_tag_decode(ctx, tag)) | |
201 | return 0; | |
202 | } | |
203 | return 1; | |
204 | } | |
205 | ||
206 | static unsigned char asn1_length_decode(struct asn1_ctx *ctx, | |
e905a9ed YH |
207 | unsigned int *def, |
208 | unsigned int *len) | |
807467c2 PM |
209 | { |
210 | unsigned char ch, cnt; | |
211 | ||
212 | if (!asn1_octet_decode(ctx, &ch)) | |
213 | return 0; | |
214 | ||
215 | if (ch == 0x80) | |
216 | *def = 0; | |
217 | else { | |
218 | *def = 1; | |
219 | ||
220 | if (ch < 0x80) | |
221 | *len = ch; | |
222 | else { | |
72b72949 | 223 | cnt = ch & 0x7F; |
807467c2 PM |
224 | *len = 0; |
225 | ||
226 | while (cnt > 0) { | |
227 | if (!asn1_octet_decode(ctx, &ch)) | |
228 | return 0; | |
229 | *len <<= 8; | |
230 | *len |= ch; | |
231 | cnt--; | |
232 | } | |
233 | } | |
234 | } | |
ddb2c435 CW |
235 | |
236 | /* don't trust len bigger than ctx buffer */ | |
237 | if (*len > ctx->end - ctx->pointer) | |
238 | return 0; | |
239 | ||
807467c2 PM |
240 | return 1; |
241 | } | |
242 | ||
243 | static unsigned char asn1_header_decode(struct asn1_ctx *ctx, | |
e905a9ed YH |
244 | unsigned char **eoc, |
245 | unsigned int *cls, | |
246 | unsigned int *con, | |
247 | unsigned int *tag) | |
807467c2 PM |
248 | { |
249 | unsigned int def, len; | |
250 | ||
251 | if (!asn1_id_decode(ctx, cls, con, tag)) | |
252 | return 0; | |
253 | ||
254 | def = len = 0; | |
255 | if (!asn1_length_decode(ctx, &def, &len)) | |
256 | return 0; | |
257 | ||
ddb2c435 CW |
258 | /* primitive shall be definite, indefinite shall be constructed */ |
259 | if (*con == ASN1_PRI && !def) | |
260 | return 0; | |
261 | ||
807467c2 PM |
262 | if (def) |
263 | *eoc = ctx->pointer + len; | |
264 | else | |
265 | *eoc = NULL; | |
266 | return 1; | |
267 | } | |
268 | ||
269 | static unsigned char asn1_eoc_decode(struct asn1_ctx *ctx, unsigned char *eoc) | |
270 | { | |
271 | unsigned char ch; | |
272 | ||
06aa1072 | 273 | if (eoc == NULL) { |
807467c2 PM |
274 | if (!asn1_octet_decode(ctx, &ch)) |
275 | return 0; | |
276 | ||
277 | if (ch != 0x00) { | |
278 | ctx->error = ASN1_ERR_DEC_EOC_MISMATCH; | |
279 | return 0; | |
280 | } | |
281 | ||
282 | if (!asn1_octet_decode(ctx, &ch)) | |
283 | return 0; | |
284 | ||
285 | if (ch != 0x00) { | |
286 | ctx->error = ASN1_ERR_DEC_EOC_MISMATCH; | |
287 | return 0; | |
288 | } | |
289 | return 1; | |
290 | } else { | |
291 | if (ctx->pointer != eoc) { | |
292 | ctx->error = ASN1_ERR_DEC_LENGTH_MISMATCH; | |
293 | return 0; | |
294 | } | |
295 | return 1; | |
296 | } | |
297 | } | |
298 | ||
299 | static unsigned char asn1_null_decode(struct asn1_ctx *ctx, unsigned char *eoc) | |
300 | { | |
301 | ctx->pointer = eoc; | |
302 | return 1; | |
303 | } | |
304 | ||
305 | static unsigned char asn1_long_decode(struct asn1_ctx *ctx, | |
e905a9ed YH |
306 | unsigned char *eoc, |
307 | long *integer) | |
807467c2 PM |
308 | { |
309 | unsigned char ch; | |
310 | unsigned int len; | |
311 | ||
312 | if (!asn1_octet_decode(ctx, &ch)) | |
313 | return 0; | |
314 | ||
315 | *integer = (signed char) ch; | |
316 | len = 1; | |
317 | ||
318 | while (ctx->pointer < eoc) { | |
319 | if (++len > sizeof (long)) { | |
320 | ctx->error = ASN1_ERR_DEC_BADVALUE; | |
321 | return 0; | |
322 | } | |
323 | ||
324 | if (!asn1_octet_decode(ctx, &ch)) | |
325 | return 0; | |
326 | ||
327 | *integer <<= 8; | |
328 | *integer |= ch; | |
329 | } | |
330 | return 1; | |
331 | } | |
332 | ||
333 | static unsigned char asn1_uint_decode(struct asn1_ctx *ctx, | |
e905a9ed YH |
334 | unsigned char *eoc, |
335 | unsigned int *integer) | |
807467c2 PM |
336 | { |
337 | unsigned char ch; | |
338 | unsigned int len; | |
339 | ||
340 | if (!asn1_octet_decode(ctx, &ch)) | |
341 | return 0; | |
342 | ||
343 | *integer = ch; | |
344 | if (ch == 0) len = 0; | |
345 | else len = 1; | |
346 | ||
347 | while (ctx->pointer < eoc) { | |
348 | if (++len > sizeof (unsigned int)) { | |
349 | ctx->error = ASN1_ERR_DEC_BADVALUE; | |
350 | return 0; | |
351 | } | |
352 | ||
353 | if (!asn1_octet_decode(ctx, &ch)) | |
354 | return 0; | |
355 | ||
356 | *integer <<= 8; | |
357 | *integer |= ch; | |
358 | } | |
359 | return 1; | |
360 | } | |
361 | ||
362 | static unsigned char asn1_ulong_decode(struct asn1_ctx *ctx, | |
e905a9ed YH |
363 | unsigned char *eoc, |
364 | unsigned long *integer) | |
807467c2 PM |
365 | { |
366 | unsigned char ch; | |
367 | unsigned int len; | |
368 | ||
369 | if (!asn1_octet_decode(ctx, &ch)) | |
370 | return 0; | |
371 | ||
372 | *integer = ch; | |
373 | if (ch == 0) len = 0; | |
374 | else len = 1; | |
375 | ||
376 | while (ctx->pointer < eoc) { | |
377 | if (++len > sizeof (unsigned long)) { | |
378 | ctx->error = ASN1_ERR_DEC_BADVALUE; | |
379 | return 0; | |
380 | } | |
381 | ||
382 | if (!asn1_octet_decode(ctx, &ch)) | |
383 | return 0; | |
384 | ||
385 | *integer <<= 8; | |
386 | *integer |= ch; | |
387 | } | |
388 | return 1; | |
389 | } | |
390 | ||
391 | static unsigned char asn1_octets_decode(struct asn1_ctx *ctx, | |
e905a9ed YH |
392 | unsigned char *eoc, |
393 | unsigned char **octets, | |
394 | unsigned int *len) | |
807467c2 PM |
395 | { |
396 | unsigned char *ptr; | |
397 | ||
398 | *len = 0; | |
399 | ||
400 | *octets = kmalloc(eoc - ctx->pointer, GFP_ATOMIC); | |
401 | if (*octets == NULL) { | |
402 | if (net_ratelimit()) | |
403 | printk("OOM in bsalg (%d)\n", __LINE__); | |
404 | return 0; | |
405 | } | |
406 | ||
407 | ptr = *octets; | |
408 | while (ctx->pointer < eoc) { | |
409 | if (!asn1_octet_decode(ctx, (unsigned char *)ptr++)) { | |
410 | kfree(*octets); | |
411 | *octets = NULL; | |
412 | return 0; | |
413 | } | |
414 | (*len)++; | |
415 | } | |
416 | return 1; | |
417 | } | |
418 | ||
419 | static unsigned char asn1_subid_decode(struct asn1_ctx *ctx, | |
e905a9ed | 420 | unsigned long *subid) |
807467c2 PM |
421 | { |
422 | unsigned char ch; | |
423 | ||
424 | *subid = 0; | |
425 | ||
426 | do { | |
427 | if (!asn1_octet_decode(ctx, &ch)) | |
428 | return 0; | |
429 | ||
430 | *subid <<= 7; | |
431 | *subid |= ch & 0x7F; | |
432 | } while ((ch & 0x80) == 0x80); | |
433 | return 1; | |
434 | } | |
435 | ||
436 | static unsigned char asn1_oid_decode(struct asn1_ctx *ctx, | |
e905a9ed YH |
437 | unsigned char *eoc, |
438 | unsigned long **oid, | |
439 | unsigned int *len) | |
807467c2 PM |
440 | { |
441 | unsigned long subid; | |
807467c2 | 442 | unsigned long *optr; |
252815b0 | 443 | size_t size; |
807467c2 PM |
444 | |
445 | size = eoc - ctx->pointer + 1; | |
ddb2c435 CW |
446 | |
447 | /* first subid actually encodes first two subids */ | |
448 | if (size < 2 || size > ULONG_MAX/sizeof(unsigned long)) | |
449 | return 0; | |
450 | ||
807467c2 PM |
451 | *oid = kmalloc(size * sizeof(unsigned long), GFP_ATOMIC); |
452 | if (*oid == NULL) { | |
453 | if (net_ratelimit()) | |
454 | printk("OOM in bsalg (%d)\n", __LINE__); | |
455 | return 0; | |
456 | } | |
457 | ||
458 | optr = *oid; | |
459 | ||
460 | if (!asn1_subid_decode(ctx, &subid)) { | |
461 | kfree(*oid); | |
462 | *oid = NULL; | |
463 | return 0; | |
464 | } | |
465 | ||
466 | if (subid < 40) { | |
467 | optr [0] = 0; | |
468 | optr [1] = subid; | |
469 | } else if (subid < 80) { | |
470 | optr [0] = 1; | |
471 | optr [1] = subid - 40; | |
472 | } else { | |
473 | optr [0] = 2; | |
474 | optr [1] = subid - 80; | |
475 | } | |
476 | ||
477 | *len = 2; | |
478 | optr += 2; | |
479 | ||
480 | while (ctx->pointer < eoc) { | |
481 | if (++(*len) > size) { | |
482 | ctx->error = ASN1_ERR_DEC_BADVALUE; | |
483 | kfree(*oid); | |
484 | *oid = NULL; | |
485 | return 0; | |
486 | } | |
487 | ||
488 | if (!asn1_subid_decode(ctx, optr++)) { | |
489 | kfree(*oid); | |
490 | *oid = NULL; | |
491 | return 0; | |
492 | } | |
493 | } | |
494 | return 1; | |
495 | } | |
496 | ||
497 | /***************************************************************************** | |
498 | * | |
499 | * SNMP decoding routines (gxsnmp author Dirk Wisse) | |
500 | * | |
501 | *****************************************************************************/ | |
502 | ||
503 | /* SNMP Versions */ | |
504 | #define SNMP_V1 0 | |
505 | #define SNMP_V2C 1 | |
506 | #define SNMP_V2 2 | |
507 | #define SNMP_V3 3 | |
508 | ||
509 | /* Default Sizes */ | |
510 | #define SNMP_SIZE_COMM 256 | |
511 | #define SNMP_SIZE_OBJECTID 128 | |
512 | #define SNMP_SIZE_BUFCHR 256 | |
513 | #define SNMP_SIZE_BUFINT 128 | |
514 | #define SNMP_SIZE_SMALLOBJECTID 16 | |
515 | ||
516 | /* Requests */ | |
517 | #define SNMP_PDU_GET 0 | |
518 | #define SNMP_PDU_NEXT 1 | |
519 | #define SNMP_PDU_RESPONSE 2 | |
520 | #define SNMP_PDU_SET 3 | |
521 | #define SNMP_PDU_TRAP1 4 | |
522 | #define SNMP_PDU_BULK 5 | |
523 | #define SNMP_PDU_INFORM 6 | |
524 | #define SNMP_PDU_TRAP2 7 | |
525 | ||
526 | /* Errors */ | |
527 | #define SNMP_NOERROR 0 | |
528 | #define SNMP_TOOBIG 1 | |
529 | #define SNMP_NOSUCHNAME 2 | |
530 | #define SNMP_BADVALUE 3 | |
531 | #define SNMP_READONLY 4 | |
532 | #define SNMP_GENERROR 5 | |
533 | #define SNMP_NOACCESS 6 | |
534 | #define SNMP_WRONGTYPE 7 | |
535 | #define SNMP_WRONGLENGTH 8 | |
536 | #define SNMP_WRONGENCODING 9 | |
537 | #define SNMP_WRONGVALUE 10 | |
538 | #define SNMP_NOCREATION 11 | |
539 | #define SNMP_INCONSISTENTVALUE 12 | |
540 | #define SNMP_RESOURCEUNAVAILABLE 13 | |
541 | #define SNMP_COMMITFAILED 14 | |
542 | #define SNMP_UNDOFAILED 15 | |
543 | #define SNMP_AUTHORIZATIONERROR 16 | |
544 | #define SNMP_NOTWRITABLE 17 | |
545 | #define SNMP_INCONSISTENTNAME 18 | |
546 | ||
547 | /* General SNMP V1 Traps */ | |
548 | #define SNMP_TRAP_COLDSTART 0 | |
549 | #define SNMP_TRAP_WARMSTART 1 | |
550 | #define SNMP_TRAP_LINKDOWN 2 | |
551 | #define SNMP_TRAP_LINKUP 3 | |
552 | #define SNMP_TRAP_AUTFAILURE 4 | |
553 | #define SNMP_TRAP_EQPNEIGHBORLOSS 5 | |
554 | #define SNMP_TRAP_ENTSPECIFIC 6 | |
555 | ||
556 | /* SNMPv1 Types */ | |
557 | #define SNMP_NULL 0 | |
558 | #define SNMP_INTEGER 1 /* l */ | |
559 | #define SNMP_OCTETSTR 2 /* c */ | |
560 | #define SNMP_DISPLAYSTR 2 /* c */ | |
561 | #define SNMP_OBJECTID 3 /* ul */ | |
562 | #define SNMP_IPADDR 4 /* uc */ | |
563 | #define SNMP_COUNTER 5 /* ul */ | |
564 | #define SNMP_GAUGE 6 /* ul */ | |
565 | #define SNMP_TIMETICKS 7 /* ul */ | |
566 | #define SNMP_OPAQUE 8 /* c */ | |
567 | ||
568 | /* Additional SNMPv2 Types */ | |
569 | #define SNMP_UINTEGER 5 /* ul */ | |
570 | #define SNMP_BITSTR 9 /* uc */ | |
571 | #define SNMP_NSAP 10 /* uc */ | |
572 | #define SNMP_COUNTER64 11 /* ul */ | |
573 | #define SNMP_NOSUCHOBJECT 12 | |
574 | #define SNMP_NOSUCHINSTANCE 13 | |
575 | #define SNMP_ENDOFMIBVIEW 14 | |
576 | ||
577 | union snmp_syntax | |
578 | { | |
579 | unsigned char uc[0]; /* 8 bit unsigned */ | |
580 | char c[0]; /* 8 bit signed */ | |
581 | unsigned long ul[0]; /* 32 bit unsigned */ | |
582 | long l[0]; /* 32 bit signed */ | |
583 | }; | |
584 | ||
585 | struct snmp_object | |
586 | { | |
587 | unsigned long *id; | |
588 | unsigned int id_len; | |
589 | unsigned short type; | |
590 | unsigned int syntax_len; | |
591 | union snmp_syntax syntax; | |
592 | }; | |
593 | ||
594 | struct snmp_request | |
595 | { | |
596 | unsigned long id; | |
597 | unsigned int error_status; | |
598 | unsigned int error_index; | |
599 | }; | |
600 | ||
601 | struct snmp_v1_trap | |
602 | { | |
603 | unsigned long *id; | |
604 | unsigned int id_len; | |
605 | unsigned long ip_address; /* pointer */ | |
606 | unsigned int general; | |
607 | unsigned int specific; | |
608 | unsigned long time; | |
609 | }; | |
610 | ||
611 | /* SNMP types */ | |
612 | #define SNMP_IPA 0 | |
613 | #define SNMP_CNT 1 | |
614 | #define SNMP_GGE 2 | |
615 | #define SNMP_TIT 3 | |
616 | #define SNMP_OPQ 4 | |
617 | #define SNMP_C64 6 | |
618 | ||
619 | /* SNMP errors */ | |
620 | #define SERR_NSO 0 | |
621 | #define SERR_NSI 1 | |
622 | #define SERR_EOM 2 | |
623 | ||
624 | static inline void mangle_address(unsigned char *begin, | |
e905a9ed YH |
625 | unsigned char *addr, |
626 | const struct oct1_map *map, | |
627 | __sum16 *check); | |
807467c2 PM |
628 | struct snmp_cnv |
629 | { | |
630 | unsigned int class; | |
631 | unsigned int tag; | |
632 | int syntax; | |
633 | }; | |
634 | ||
72b72949 | 635 | static const struct snmp_cnv snmp_conv[] = { |
807467c2 PM |
636 | {ASN1_UNI, ASN1_NUL, SNMP_NULL}, |
637 | {ASN1_UNI, ASN1_INT, SNMP_INTEGER}, | |
638 | {ASN1_UNI, ASN1_OTS, SNMP_OCTETSTR}, | |
639 | {ASN1_UNI, ASN1_OTS, SNMP_DISPLAYSTR}, | |
640 | {ASN1_UNI, ASN1_OJI, SNMP_OBJECTID}, | |
641 | {ASN1_APL, SNMP_IPA, SNMP_IPADDR}, | |
642 | {ASN1_APL, SNMP_CNT, SNMP_COUNTER}, /* Counter32 */ | |
643 | {ASN1_APL, SNMP_GGE, SNMP_GAUGE}, /* Gauge32 == Unsigned32 */ | |
644 | {ASN1_APL, SNMP_TIT, SNMP_TIMETICKS}, | |
645 | {ASN1_APL, SNMP_OPQ, SNMP_OPAQUE}, | |
646 | ||
647 | /* SNMPv2 data types and errors */ | |
648 | {ASN1_UNI, ASN1_BTS, SNMP_BITSTR}, | |
649 | {ASN1_APL, SNMP_C64, SNMP_COUNTER64}, | |
650 | {ASN1_CTX, SERR_NSO, SNMP_NOSUCHOBJECT}, | |
651 | {ASN1_CTX, SERR_NSI, SNMP_NOSUCHINSTANCE}, | |
652 | {ASN1_CTX, SERR_EOM, SNMP_ENDOFMIBVIEW}, | |
653 | {0, 0, -1} | |
654 | }; | |
655 | ||
656 | static unsigned char snmp_tag_cls2syntax(unsigned int tag, | |
e905a9ed YH |
657 | unsigned int cls, |
658 | unsigned short *syntax) | |
807467c2 | 659 | { |
72b72949 | 660 | const struct snmp_cnv *cnv; |
807467c2 PM |
661 | |
662 | cnv = snmp_conv; | |
663 | ||
664 | while (cnv->syntax != -1) { | |
665 | if (cnv->tag == tag && cnv->class == cls) { | |
666 | *syntax = cnv->syntax; | |
667 | return 1; | |
668 | } | |
669 | cnv++; | |
670 | } | |
671 | return 0; | |
672 | } | |
673 | ||
674 | static unsigned char snmp_object_decode(struct asn1_ctx *ctx, | |
e905a9ed | 675 | struct snmp_object **obj) |
807467c2 PM |
676 | { |
677 | unsigned int cls, con, tag, len, idlen; | |
678 | unsigned short type; | |
679 | unsigned char *eoc, *end, *p; | |
680 | unsigned long *lp, *id; | |
681 | unsigned long ul; | |
682 | long l; | |
683 | ||
684 | *obj = NULL; | |
685 | id = NULL; | |
686 | ||
687 | if (!asn1_header_decode(ctx, &eoc, &cls, &con, &tag)) | |
688 | return 0; | |
689 | ||
690 | if (cls != ASN1_UNI || con != ASN1_CON || tag != ASN1_SEQ) | |
691 | return 0; | |
692 | ||
693 | if (!asn1_header_decode(ctx, &end, &cls, &con, &tag)) | |
694 | return 0; | |
695 | ||
696 | if (cls != ASN1_UNI || con != ASN1_PRI || tag != ASN1_OJI) | |
697 | return 0; | |
698 | ||
699 | if (!asn1_oid_decode(ctx, end, &id, &idlen)) | |
700 | return 0; | |
701 | ||
702 | if (!asn1_header_decode(ctx, &end, &cls, &con, &tag)) { | |
703 | kfree(id); | |
704 | return 0; | |
705 | } | |
706 | ||
707 | if (con != ASN1_PRI) { | |
708 | kfree(id); | |
709 | return 0; | |
710 | } | |
711 | ||
712 | type = 0; | |
713 | if (!snmp_tag_cls2syntax(tag, cls, &type)) { | |
714 | kfree(id); | |
715 | return 0; | |
716 | } | |
717 | ||
718 | l = 0; | |
719 | switch (type) { | |
720 | case SNMP_INTEGER: | |
721 | len = sizeof(long); | |
722 | if (!asn1_long_decode(ctx, end, &l)) { | |
723 | kfree(id); | |
724 | return 0; | |
725 | } | |
726 | *obj = kmalloc(sizeof(struct snmp_object) + len, | |
e905a9ed | 727 | GFP_ATOMIC); |
807467c2 PM |
728 | if (*obj == NULL) { |
729 | kfree(id); | |
730 | if (net_ratelimit()) | |
731 | printk("OOM in bsalg (%d)\n", __LINE__); | |
732 | return 0; | |
733 | } | |
734 | (*obj)->syntax.l[0] = l; | |
735 | break; | |
736 | case SNMP_OCTETSTR: | |
737 | case SNMP_OPAQUE: | |
738 | if (!asn1_octets_decode(ctx, end, &p, &len)) { | |
739 | kfree(id); | |
740 | return 0; | |
741 | } | |
742 | *obj = kmalloc(sizeof(struct snmp_object) + len, | |
e905a9ed | 743 | GFP_ATOMIC); |
807467c2 | 744 | if (*obj == NULL) { |
311670f3 | 745 | kfree(p); |
807467c2 PM |
746 | kfree(id); |
747 | if (net_ratelimit()) | |
748 | printk("OOM in bsalg (%d)\n", __LINE__); | |
749 | return 0; | |
750 | } | |
751 | memcpy((*obj)->syntax.c, p, len); | |
752 | kfree(p); | |
753 | break; | |
754 | case SNMP_NULL: | |
755 | case SNMP_NOSUCHOBJECT: | |
756 | case SNMP_NOSUCHINSTANCE: | |
757 | case SNMP_ENDOFMIBVIEW: | |
758 | len = 0; | |
759 | *obj = kmalloc(sizeof(struct snmp_object), GFP_ATOMIC); | |
760 | if (*obj == NULL) { | |
761 | kfree(id); | |
762 | if (net_ratelimit()) | |
763 | printk("OOM in bsalg (%d)\n", __LINE__); | |
764 | return 0; | |
765 | } | |
766 | if (!asn1_null_decode(ctx, end)) { | |
767 | kfree(id); | |
768 | kfree(*obj); | |
769 | *obj = NULL; | |
770 | return 0; | |
771 | } | |
772 | break; | |
773 | case SNMP_OBJECTID: | |
774 | if (!asn1_oid_decode(ctx, end, (unsigned long **)&lp, &len)) { | |
775 | kfree(id); | |
776 | return 0; | |
777 | } | |
778 | len *= sizeof(unsigned long); | |
779 | *obj = kmalloc(sizeof(struct snmp_object) + len, GFP_ATOMIC); | |
780 | if (*obj == NULL) { | |
781 | kfree(lp); | |
782 | kfree(id); | |
783 | if (net_ratelimit()) | |
784 | printk("OOM in bsalg (%d)\n", __LINE__); | |
785 | return 0; | |
786 | } | |
787 | memcpy((*obj)->syntax.ul, lp, len); | |
788 | kfree(lp); | |
789 | break; | |
790 | case SNMP_IPADDR: | |
791 | if (!asn1_octets_decode(ctx, end, &p, &len)) { | |
792 | kfree(id); | |
793 | return 0; | |
794 | } | |
795 | if (len != 4) { | |
796 | kfree(p); | |
797 | kfree(id); | |
798 | return 0; | |
799 | } | |
800 | *obj = kmalloc(sizeof(struct snmp_object) + len, GFP_ATOMIC); | |
801 | if (*obj == NULL) { | |
802 | kfree(p); | |
803 | kfree(id); | |
804 | if (net_ratelimit()) | |
805 | printk("OOM in bsalg (%d)\n", __LINE__); | |
806 | return 0; | |
807 | } | |
808 | memcpy((*obj)->syntax.uc, p, len); | |
809 | kfree(p); | |
810 | break; | |
811 | case SNMP_COUNTER: | |
812 | case SNMP_GAUGE: | |
813 | case SNMP_TIMETICKS: | |
814 | len = sizeof(unsigned long); | |
815 | if (!asn1_ulong_decode(ctx, end, &ul)) { | |
816 | kfree(id); | |
817 | return 0; | |
818 | } | |
819 | *obj = kmalloc(sizeof(struct snmp_object) + len, GFP_ATOMIC); | |
820 | if (*obj == NULL) { | |
821 | kfree(id); | |
822 | if (net_ratelimit()) | |
823 | printk("OOM in bsalg (%d)\n", __LINE__); | |
824 | return 0; | |
825 | } | |
826 | (*obj)->syntax.ul[0] = ul; | |
827 | break; | |
828 | default: | |
829 | kfree(id); | |
830 | return 0; | |
831 | } | |
832 | ||
833 | (*obj)->syntax_len = len; | |
834 | (*obj)->type = type; | |
835 | (*obj)->id = id; | |
836 | (*obj)->id_len = idlen; | |
837 | ||
838 | if (!asn1_eoc_decode(ctx, eoc)) { | |
839 | kfree(id); | |
840 | kfree(*obj); | |
841 | *obj = NULL; | |
842 | return 0; | |
843 | } | |
844 | return 1; | |
845 | } | |
846 | ||
847 | static unsigned char snmp_request_decode(struct asn1_ctx *ctx, | |
e905a9ed | 848 | struct snmp_request *request) |
807467c2 PM |
849 | { |
850 | unsigned int cls, con, tag; | |
851 | unsigned char *end; | |
852 | ||
853 | if (!asn1_header_decode(ctx, &end, &cls, &con, &tag)) | |
854 | return 0; | |
855 | ||
856 | if (cls != ASN1_UNI || con != ASN1_PRI || tag != ASN1_INT) | |
857 | return 0; | |
858 | ||
859 | if (!asn1_ulong_decode(ctx, end, &request->id)) | |
860 | return 0; | |
861 | ||
862 | if (!asn1_header_decode(ctx, &end, &cls, &con, &tag)) | |
863 | return 0; | |
864 | ||
865 | if (cls != ASN1_UNI || con != ASN1_PRI || tag != ASN1_INT) | |
866 | return 0; | |
867 | ||
868 | if (!asn1_uint_decode(ctx, end, &request->error_status)) | |
869 | return 0; | |
870 | ||
871 | if (!asn1_header_decode(ctx, &end, &cls, &con, &tag)) | |
872 | return 0; | |
873 | ||
874 | if (cls != ASN1_UNI || con != ASN1_PRI || tag != ASN1_INT) | |
875 | return 0; | |
876 | ||
877 | if (!asn1_uint_decode(ctx, end, &request->error_index)) | |
878 | return 0; | |
879 | ||
880 | return 1; | |
881 | } | |
882 | ||
883 | /* | |
884 | * Fast checksum update for possibly oddly-aligned UDP byte, from the | |
885 | * code example in the draft. | |
886 | */ | |
887 | static void fast_csum(__sum16 *csum, | |
e905a9ed YH |
888 | const unsigned char *optr, |
889 | const unsigned char *nptr, | |
890 | int offset) | |
807467c2 PM |
891 | { |
892 | unsigned char s[4]; | |
893 | ||
894 | if (offset & 1) { | |
895 | s[0] = s[2] = 0; | |
896 | s[1] = ~*optr; | |
897 | s[3] = *nptr; | |
898 | } else { | |
899 | s[1] = s[3] = 0; | |
900 | s[0] = ~*optr; | |
901 | s[2] = *nptr; | |
902 | } | |
903 | ||
904 | *csum = csum_fold(csum_partial(s, 4, ~csum_unfold(*csum))); | |
905 | } | |
906 | ||
907 | /* | |
908 | * Mangle IP address. | |
909 | * - begin points to the start of the snmp messgae | |
910 | * - addr points to the start of the address | |
911 | */ | |
912 | static inline void mangle_address(unsigned char *begin, | |
e905a9ed YH |
913 | unsigned char *addr, |
914 | const struct oct1_map *map, | |
915 | __sum16 *check) | |
807467c2 PM |
916 | { |
917 | if (map->from == NOCT1(addr)) { | |
918 | u_int32_t old; | |
919 | ||
920 | if (debug) | |
72b72949 | 921 | memcpy(&old, addr, sizeof(old)); |
807467c2 PM |
922 | |
923 | *addr = map->to; | |
924 | ||
925 | /* Update UDP checksum if being used */ | |
926 | if (*check) { | |
927 | fast_csum(check, | |
e905a9ed | 928 | &map->from, &map->to, addr - begin); |
807467c2 PM |
929 | |
930 | } | |
931 | ||
932 | if (debug) | |
cffee385 HH |
933 | printk(KERN_DEBUG "bsalg: mapped %pI4 to %pI4\n", |
934 | &old, addr); | |
807467c2 PM |
935 | } |
936 | } | |
937 | ||
938 | static unsigned char snmp_trap_decode(struct asn1_ctx *ctx, | |
e905a9ed YH |
939 | struct snmp_v1_trap *trap, |
940 | const struct oct1_map *map, | |
941 | __sum16 *check) | |
807467c2 PM |
942 | { |
943 | unsigned int cls, con, tag, len; | |
944 | unsigned char *end; | |
945 | ||
946 | if (!asn1_header_decode(ctx, &end, &cls, &con, &tag)) | |
947 | return 0; | |
948 | ||
949 | if (cls != ASN1_UNI || con != ASN1_PRI || tag != ASN1_OJI) | |
950 | return 0; | |
951 | ||
952 | if (!asn1_oid_decode(ctx, end, &trap->id, &trap->id_len)) | |
953 | return 0; | |
954 | ||
955 | if (!asn1_header_decode(ctx, &end, &cls, &con, &tag)) | |
956 | goto err_id_free; | |
957 | ||
958 | if (!((cls == ASN1_APL && con == ASN1_PRI && tag == SNMP_IPA) || | |
959 | (cls == ASN1_UNI && con == ASN1_PRI && tag == ASN1_OTS))) | |
960 | goto err_id_free; | |
961 | ||
962 | if (!asn1_octets_decode(ctx, end, (unsigned char **)&trap->ip_address, &len)) | |
963 | goto err_id_free; | |
964 | ||
965 | /* IPv4 only */ | |
966 | if (len != 4) | |
967 | goto err_addr_free; | |
968 | ||
969 | mangle_address(ctx->begin, ctx->pointer - 4, map, check); | |
970 | ||
971 | if (!asn1_header_decode(ctx, &end, &cls, &con, &tag)) | |
972 | goto err_addr_free; | |
973 | ||
974 | if (cls != ASN1_UNI || con != ASN1_PRI || tag != ASN1_INT) | |
975 | goto err_addr_free; | |
976 | ||
977 | if (!asn1_uint_decode(ctx, end, &trap->general)) | |
978 | goto err_addr_free; | |
979 | ||
980 | if (!asn1_header_decode(ctx, &end, &cls, &con, &tag)) | |
981 | goto err_addr_free; | |
982 | ||
983 | if (cls != ASN1_UNI || con != ASN1_PRI || tag != ASN1_INT) | |
984 | goto err_addr_free; | |
985 | ||
986 | if (!asn1_uint_decode(ctx, end, &trap->specific)) | |
987 | goto err_addr_free; | |
988 | ||
989 | if (!asn1_header_decode(ctx, &end, &cls, &con, &tag)) | |
990 | goto err_addr_free; | |
991 | ||
992 | if (!((cls == ASN1_APL && con == ASN1_PRI && tag == SNMP_TIT) || | |
993 | (cls == ASN1_UNI && con == ASN1_PRI && tag == ASN1_INT))) | |
994 | goto err_addr_free; | |
995 | ||
996 | if (!asn1_ulong_decode(ctx, end, &trap->time)) | |
997 | goto err_addr_free; | |
998 | ||
999 | return 1; | |
1000 | ||
1001 | err_addr_free: | |
1002 | kfree((unsigned long *)trap->ip_address); | |
1003 | ||
1004 | err_id_free: | |
1005 | kfree(trap->id); | |
1006 | ||
1007 | return 0; | |
1008 | } | |
1009 | ||
1010 | /***************************************************************************** | |
1011 | * | |
1012 | * Misc. routines | |
1013 | * | |
1014 | *****************************************************************************/ | |
1015 | ||
72b72949 | 1016 | static void hex_dump(const unsigned char *buf, size_t len) |
807467c2 PM |
1017 | { |
1018 | size_t i; | |
1019 | ||
1020 | for (i = 0; i < len; i++) { | |
1021 | if (i && !(i % 16)) | |
1022 | printk("\n"); | |
1023 | printk("%02x ", *(buf + i)); | |
1024 | } | |
1025 | printk("\n"); | |
1026 | } | |
1027 | ||
1028 | /* | |
1029 | * Parse and mangle SNMP message according to mapping. | |
1030 | * (And this is the fucking 'basic' method). | |
1031 | */ | |
1032 | static int snmp_parse_mangle(unsigned char *msg, | |
e905a9ed YH |
1033 | u_int16_t len, |
1034 | const struct oct1_map *map, | |
1035 | __sum16 *check) | |
807467c2 PM |
1036 | { |
1037 | unsigned char *eoc, *end; | |
1038 | unsigned int cls, con, tag, vers, pdutype; | |
1039 | struct asn1_ctx ctx; | |
1040 | struct asn1_octstr comm; | |
1041 | struct snmp_object **obj; | |
1042 | ||
1043 | if (debug > 1) | |
1044 | hex_dump(msg, len); | |
1045 | ||
1046 | asn1_open(&ctx, msg, len); | |
1047 | ||
1048 | /* | |
1049 | * Start of SNMP message. | |
1050 | */ | |
1051 | if (!asn1_header_decode(&ctx, &eoc, &cls, &con, &tag)) | |
1052 | return 0; | |
1053 | if (cls != ASN1_UNI || con != ASN1_CON || tag != ASN1_SEQ) | |
1054 | return 0; | |
1055 | ||
1056 | /* | |
1057 | * Version 1 or 2 handled. | |
1058 | */ | |
1059 | if (!asn1_header_decode(&ctx, &end, &cls, &con, &tag)) | |
1060 | return 0; | |
1061 | if (cls != ASN1_UNI || con != ASN1_PRI || tag != ASN1_INT) | |
1062 | return 0; | |
1063 | if (!asn1_uint_decode (&ctx, end, &vers)) | |
1064 | return 0; | |
1065 | if (debug > 1) | |
1066 | printk(KERN_DEBUG "bsalg: snmp version: %u\n", vers + 1); | |
1067 | if (vers > 1) | |
1068 | return 1; | |
1069 | ||
1070 | /* | |
1071 | * Community. | |
1072 | */ | |
1073 | if (!asn1_header_decode (&ctx, &end, &cls, &con, &tag)) | |
1074 | return 0; | |
1075 | if (cls != ASN1_UNI || con != ASN1_PRI || tag != ASN1_OTS) | |
1076 | return 0; | |
1077 | if (!asn1_octets_decode(&ctx, end, &comm.data, &comm.len)) | |
1078 | return 0; | |
1079 | if (debug > 1) { | |
1080 | unsigned int i; | |
1081 | ||
1082 | printk(KERN_DEBUG "bsalg: community: "); | |
1083 | for (i = 0; i < comm.len; i++) | |
1084 | printk("%c", comm.data[i]); | |
1085 | printk("\n"); | |
1086 | } | |
1087 | kfree(comm.data); | |
1088 | ||
1089 | /* | |
1090 | * PDU type | |
1091 | */ | |
1092 | if (!asn1_header_decode(&ctx, &eoc, &cls, &con, &pdutype)) | |
1093 | return 0; | |
1094 | if (cls != ASN1_CTX || con != ASN1_CON) | |
1095 | return 0; | |
1096 | if (debug > 1) { | |
72b72949 | 1097 | static const unsigned char *const pdus[] = { |
807467c2 PM |
1098 | [SNMP_PDU_GET] = "get", |
1099 | [SNMP_PDU_NEXT] = "get-next", | |
1100 | [SNMP_PDU_RESPONSE] = "response", | |
1101 | [SNMP_PDU_SET] = "set", | |
1102 | [SNMP_PDU_TRAP1] = "trapv1", | |
1103 | [SNMP_PDU_BULK] = "bulk", | |
1104 | [SNMP_PDU_INFORM] = "inform", | |
1105 | [SNMP_PDU_TRAP2] = "trapv2" | |
1106 | }; | |
1107 | ||
1108 | if (pdutype > SNMP_PDU_TRAP2) | |
1109 | printk(KERN_DEBUG "bsalg: bad pdu type %u\n", pdutype); | |
1110 | else | |
1111 | printk(KERN_DEBUG "bsalg: pdu: %s\n", pdus[pdutype]); | |
1112 | } | |
1113 | if (pdutype != SNMP_PDU_RESPONSE && | |
1114 | pdutype != SNMP_PDU_TRAP1 && pdutype != SNMP_PDU_TRAP2) | |
1115 | return 1; | |
1116 | ||
1117 | /* | |
1118 | * Request header or v1 trap | |
1119 | */ | |
1120 | if (pdutype == SNMP_PDU_TRAP1) { | |
1121 | struct snmp_v1_trap trap; | |
1122 | unsigned char ret = snmp_trap_decode(&ctx, &trap, map, check); | |
1123 | ||
1124 | if (ret) { | |
1125 | kfree(trap.id); | |
1126 | kfree((unsigned long *)trap.ip_address); | |
1127 | } else | |
1128 | return ret; | |
1129 | ||
1130 | } else { | |
1131 | struct snmp_request req; | |
1132 | ||
1133 | if (!snmp_request_decode(&ctx, &req)) | |
1134 | return 0; | |
1135 | ||
1136 | if (debug > 1) | |
1137 | printk(KERN_DEBUG "bsalg: request: id=0x%lx error_status=%u " | |
1138 | "error_index=%u\n", req.id, req.error_status, | |
1139 | req.error_index); | |
1140 | } | |
1141 | ||
1142 | /* | |
1143 | * Loop through objects, look for IP addresses to mangle. | |
1144 | */ | |
1145 | if (!asn1_header_decode(&ctx, &eoc, &cls, &con, &tag)) | |
1146 | return 0; | |
1147 | ||
1148 | if (cls != ASN1_UNI || con != ASN1_CON || tag != ASN1_SEQ) | |
1149 | return 0; | |
1150 | ||
1151 | obj = kmalloc(sizeof(struct snmp_object), GFP_ATOMIC); | |
1152 | if (obj == NULL) { | |
1153 | if (net_ratelimit()) | |
1154 | printk(KERN_WARNING "OOM in bsalg(%d)\n", __LINE__); | |
1155 | return 0; | |
1156 | } | |
1157 | ||
1158 | while (!asn1_eoc_decode(&ctx, eoc)) { | |
1159 | unsigned int i; | |
1160 | ||
1161 | if (!snmp_object_decode(&ctx, obj)) { | |
1162 | if (*obj) { | |
1163 | kfree((*obj)->id); | |
1164 | kfree(*obj); | |
1165 | } | |
1166 | kfree(obj); | |
1167 | return 0; | |
1168 | } | |
1169 | ||
1170 | if (debug > 1) { | |
1171 | printk(KERN_DEBUG "bsalg: object: "); | |
1172 | for (i = 0; i < (*obj)->id_len; i++) { | |
1173 | if (i > 0) | |
1174 | printk("."); | |
1175 | printk("%lu", (*obj)->id[i]); | |
1176 | } | |
1177 | printk(": type=%u\n", (*obj)->type); | |
1178 | ||
1179 | } | |
1180 | ||
1181 | if ((*obj)->type == SNMP_IPADDR) | |
1182 | mangle_address(ctx.begin, ctx.pointer - 4 , map, check); | |
1183 | ||
1184 | kfree((*obj)->id); | |
1185 | kfree(*obj); | |
1186 | } | |
1187 | kfree(obj); | |
1188 | ||
1189 | if (!asn1_eoc_decode(&ctx, eoc)) | |
1190 | return 0; | |
1191 | ||
1192 | return 1; | |
1193 | } | |
1194 | ||
1195 | /***************************************************************************** | |
1196 | * | |
1197 | * NAT routines. | |
1198 | * | |
1199 | *****************************************************************************/ | |
1200 | ||
1201 | /* | |
1202 | * SNMP translation routine. | |
1203 | */ | |
1204 | static int snmp_translate(struct nf_conn *ct, | |
e905a9ed | 1205 | enum ip_conntrack_info ctinfo, |
3db05fea | 1206 | struct sk_buff *skb) |
807467c2 | 1207 | { |
3db05fea | 1208 | struct iphdr *iph = ip_hdr(skb); |
807467c2 PM |
1209 | struct udphdr *udph = (struct udphdr *)((__be32 *)iph + iph->ihl); |
1210 | u_int16_t udplen = ntohs(udph->len); | |
1211 | u_int16_t paylen = udplen - sizeof(struct udphdr); | |
1212 | int dir = CTINFO2DIR(ctinfo); | |
1213 | struct oct1_map map; | |
1214 | ||
1215 | /* | |
1216 | * Determine mappping for application layer addresses based | |
1217 | * on NAT manipulations for the packet. | |
1218 | */ | |
1219 | if (dir == IP_CT_DIR_ORIGINAL) { | |
1220 | /* SNAT traps */ | |
1221 | map.from = NOCT1(&ct->tuplehash[dir].tuple.src.u3.ip); | |
1222 | map.to = NOCT1(&ct->tuplehash[!dir].tuple.dst.u3.ip); | |
1223 | } else { | |
1224 | /* DNAT replies */ | |
1225 | map.from = NOCT1(&ct->tuplehash[dir].tuple.src.u3.ip); | |
1226 | map.to = NOCT1(&ct->tuplehash[!dir].tuple.dst.u3.ip); | |
1227 | } | |
1228 | ||
1229 | if (map.from == map.to) | |
1230 | return NF_ACCEPT; | |
1231 | ||
1232 | if (!snmp_parse_mangle((unsigned char *)udph + sizeof(struct udphdr), | |
e905a9ed | 1233 | paylen, &map, &udph->check)) { |
807467c2 PM |
1234 | if (net_ratelimit()) |
1235 | printk(KERN_WARNING "bsalg: parser failed\n"); | |
1236 | return NF_DROP; | |
1237 | } | |
1238 | return NF_ACCEPT; | |
1239 | } | |
1240 | ||
1241 | /* We don't actually set up expectations, just adjust internal IP | |
1242 | * addresses if this is being NATted */ | |
3db05fea | 1243 | static int help(struct sk_buff *skb, unsigned int protoff, |
807467c2 PM |
1244 | struct nf_conn *ct, |
1245 | enum ip_conntrack_info ctinfo) | |
1246 | { | |
1247 | int dir = CTINFO2DIR(ctinfo); | |
1248 | unsigned int ret; | |
72b72949 JE |
1249 | const struct iphdr *iph = ip_hdr(skb); |
1250 | const struct udphdr *udph = (struct udphdr *)((__be32 *)iph + iph->ihl); | |
807467c2 PM |
1251 | |
1252 | /* SNMP replies and originating SNMP traps get mangled */ | |
1253 | if (udph->source == htons(SNMP_PORT) && dir != IP_CT_DIR_REPLY) | |
1254 | return NF_ACCEPT; | |
1255 | if (udph->dest == htons(SNMP_TRAP_PORT) && dir != IP_CT_DIR_ORIGINAL) | |
1256 | return NF_ACCEPT; | |
1257 | ||
1258 | /* No NAT? */ | |
1259 | if (!(ct->status & IPS_NAT_MASK)) | |
1260 | return NF_ACCEPT; | |
1261 | ||
1262 | /* | |
1263 | * Make sure the packet length is ok. So far, we were only guaranteed | |
1264 | * to have a valid length IP header plus 8 bytes, which means we have | |
1265 | * enough room for a UDP header. Just verify the UDP length field so we | |
1266 | * can mess around with the payload. | |
1267 | */ | |
3db05fea | 1268 | if (ntohs(udph->len) != skb->len - (iph->ihl << 2)) { |
807467c2 | 1269 | if (net_ratelimit()) |
cffee385 HH |
1270 | printk(KERN_WARNING "SNMP: dropping malformed packet src=%pI4 dst=%pI4\n", |
1271 | &iph->saddr, &iph->daddr); | |
807467c2 PM |
1272 | return NF_DROP; |
1273 | } | |
1274 | ||
3db05fea | 1275 | if (!skb_make_writable(skb, skb->len)) |
807467c2 PM |
1276 | return NF_DROP; |
1277 | ||
1278 | spin_lock_bh(&snmp_lock); | |
3db05fea | 1279 | ret = snmp_translate(ct, ctinfo, skb); |
807467c2 PM |
1280 | spin_unlock_bh(&snmp_lock); |
1281 | return ret; | |
1282 | } | |
1283 | ||
6002f266 PM |
1284 | static const struct nf_conntrack_expect_policy snmp_exp_policy = { |
1285 | .max_expected = 0, | |
1286 | .timeout = 180, | |
1287 | }; | |
1288 | ||
807467c2 | 1289 | static struct nf_conntrack_helper snmp_helper __read_mostly = { |
807467c2 PM |
1290 | .me = THIS_MODULE, |
1291 | .help = help, | |
6002f266 | 1292 | .expect_policy = &snmp_exp_policy, |
807467c2 PM |
1293 | .name = "snmp", |
1294 | .tuple.src.l3num = AF_INET, | |
09640e63 | 1295 | .tuple.src.u.udp.port = cpu_to_be16(SNMP_PORT), |
807467c2 | 1296 | .tuple.dst.protonum = IPPROTO_UDP, |
807467c2 PM |
1297 | }; |
1298 | ||
1299 | static struct nf_conntrack_helper snmp_trap_helper __read_mostly = { | |
807467c2 PM |
1300 | .me = THIS_MODULE, |
1301 | .help = help, | |
6002f266 | 1302 | .expect_policy = &snmp_exp_policy, |
807467c2 PM |
1303 | .name = "snmp_trap", |
1304 | .tuple.src.l3num = AF_INET, | |
09640e63 | 1305 | .tuple.src.u.udp.port = cpu_to_be16(SNMP_TRAP_PORT), |
807467c2 | 1306 | .tuple.dst.protonum = IPPROTO_UDP, |
807467c2 PM |
1307 | }; |
1308 | ||
1309 | /***************************************************************************** | |
1310 | * | |
1311 | * Module stuff. | |
1312 | * | |
1313 | *****************************************************************************/ | |
1314 | ||
1315 | static int __init nf_nat_snmp_basic_init(void) | |
1316 | { | |
1317 | int ret = 0; | |
1318 | ||
1319 | ret = nf_conntrack_helper_register(&snmp_helper); | |
1320 | if (ret < 0) | |
1321 | return ret; | |
1322 | ret = nf_conntrack_helper_register(&snmp_trap_helper); | |
1323 | if (ret < 0) { | |
1324 | nf_conntrack_helper_unregister(&snmp_helper); | |
1325 | return ret; | |
1326 | } | |
1327 | return ret; | |
1328 | } | |
1329 | ||
1330 | static void __exit nf_nat_snmp_basic_fini(void) | |
1331 | { | |
1332 | nf_conntrack_helper_unregister(&snmp_helper); | |
1333 | nf_conntrack_helper_unregister(&snmp_trap_helper); | |
1334 | } | |
1335 | ||
1336 | module_init(nf_nat_snmp_basic_init); | |
1337 | module_exit(nf_nat_snmp_basic_fini); | |
1338 | ||
1339 | module_param(debug, int, 0600); |