1 /**
2  * Copyright 2017 Florian Forster
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a copy
5  * of this software and associated documentation files (the "Software"), to deal
6  * in the Software without restriction, including without limitation the rights
7  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8  * copies of the Software, and to permit persons to whom the Software is
9  * furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
20  * SOFTWARE.
21  *
22  * Authors:
23  *   Florian octo Forster <octo at collectd.org>
24  **/
25 
26 #include "config.h"
27 
28 #if !defined(__GNUC__) || !__GNUC__
29 #define __attribute__(x) /**/
30 #endif
31 
32 #include "collectd/lcc_features.h"
33 #include "collectd/network_parse.h"
34 #include "globals.h"
35 
36 #include <errno.h>
37 #include <math.h>
38 #include <pthread.h>
39 #include <stdbool.h>
40 #include <stdlib.h>
41 #include <string.h>
42 
43 /* for be{16,64}toh */
44 #if HAVE_ENDIAN_H
45 #include <endian.h>
46 #elif HAVE_SYS_ENDIAN_H
47 #include <sys/endian.h>
48 #else /* fallback */
49 #include "collectd/stdendian.h"
50 #endif
51 
52 #if HAVE_GCRYPT_H
53 #define GCRYPT_NO_DEPRECATED
54 #include <gcrypt.h>
55 #endif
56 
57 #include <stdio.h>
58 #define DEBUG(...) printf(__VA_ARGS__)
59 
60 #if HAVE_GCRYPT_H
61 #if GCRYPT_VERSION_NUMBER < 0x010600
62 GCRY_THREAD_OPTION_PTHREAD_IMPL;
63 #endif
64 #endif
65 
66 /* forward declaration because parse_sign_sha256()/parse_encrypt_aes256() and
67  * network_parse() need to call each other. */
68 static int network_parse(void *data, size_t data_size, lcc_security_level_t sl,
69                          lcc_network_parse_options_t const *opts);
70 
71 #if HAVE_GCRYPT_H
init_gcrypt(void)72 static int init_gcrypt(void) {
73   /* http://lists.gnupg.org/pipermail/gcrypt-devel/2003-August/000458.html
74    * Because you can't know in a library whether another library has
75    * already initialized the library */
76   if (gcry_control(GCRYCTL_ANY_INITIALIZATION_P))
77     return (0);
78 
79 /* http://www.gnupg.org/documentation/manuals/gcrypt/Multi_002dThreading.html
80  * To ensure thread-safety, it's important to set GCRYCTL_SET_THREAD_CBS
81  * *before* initalizing Libgcrypt with gcry_check_version(), which itself must
82  * be called before any other gcry_* function. GCRYCTL_ANY_INITIALIZATION_P
83  * above doesn't count, as it doesn't implicitly initalize Libgcrypt.
84  *
85  * tl;dr: keep all these gry_* statements in this exact order please. */
86 #if GCRYPT_VERSION_NUMBER < 0x010600
87   if (gcry_control(GCRYCTL_SET_THREAD_CBS, &gcry_threads_pthread)) {
88     return -1;
89   }
90 #endif
91 
92   gcry_check_version(NULL);
93 
94   if (gcry_control(GCRYCTL_INIT_SECMEM, 32768)) {
95     return -1;
96   }
97 
98   gcry_control(GCRYCTL_INITIALIZATION_FINISHED);
99   return 0;
100 }
101 #endif
102 
103 typedef struct {
104   uint8_t *data;
105   size_t len;
106 } buffer_t;
107 
buffer_next(buffer_t * b,void * out,size_t n)108 static int buffer_next(buffer_t *b, void *out, size_t n) {
109   if (b->len < n) {
110     return -1;
111   }
112   memmove(out, b->data, n);
113 
114   b->data += n;
115   b->len -= n;
116 
117   return 0;
118 }
119 
buffer_uint16(buffer_t * b,uint16_t * out)120 static int buffer_uint16(buffer_t *b, uint16_t *out) {
121   uint16_t tmp;
122   if (buffer_next(b, &tmp, sizeof(tmp)) != 0)
123     return -1;
124 
125   *out = be16toh(tmp);
126   return 0;
127 }
128 
129 #define TYPE_HOST 0x0000
130 #define TYPE_TIME 0x0001
131 #define TYPE_TIME_HR 0x0008
132 #define TYPE_PLUGIN 0x0002
133 #define TYPE_PLUGIN_INSTANCE 0x0003
134 #define TYPE_TYPE 0x0004
135 #define TYPE_TYPE_INSTANCE 0x0005
136 #define TYPE_VALUES 0x0006
137 #define TYPE_INTERVAL 0x0007
138 #define TYPE_INTERVAL_HR 0x0009
139 #define TYPE_SIGN_SHA256 0x0200
140 #define TYPE_ENCR_AES256 0x0210
141 
parse_int(void * payload,size_t payload_size,uint64_t * out)142 static int parse_int(void *payload, size_t payload_size, uint64_t *out) {
143   uint64_t tmp;
144 
145   if (payload_size != sizeof(tmp))
146     return EINVAL;
147 
148   memmove(&tmp, payload, sizeof(tmp));
149   *out = be64toh(tmp);
150   return 0;
151 }
152 
parse_string(void * payload,size_t payload_size,char * out,size_t out_size)153 static int parse_string(void *payload, size_t payload_size, char *out,
154                         size_t out_size) {
155   char *in = payload;
156 
157   if ((payload_size < 1) || (in[payload_size - 1] != '\0') ||
158       (payload_size > out_size))
159     return EINVAL;
160 
161   strncpy(out, in, out_size - 1);
162   out[out_size - 1] = '\0';
163   return 0;
164 }
165 
parse_identifier(uint16_t type,void * payload,size_t payload_size,lcc_value_list_t * state)166 static int parse_identifier(uint16_t type, void *payload, size_t payload_size,
167                             lcc_value_list_t *state) {
168   char buf[LCC_NAME_LEN];
169 
170   if (parse_string(payload, payload_size, buf, sizeof(buf)) != 0)
171     return EINVAL;
172 
173   switch (type) {
174   case TYPE_HOST:
175     memmove(state->identifier.host, buf, LCC_NAME_LEN);
176     break;
177   case TYPE_PLUGIN:
178     memmove(state->identifier.plugin, buf, LCC_NAME_LEN);
179     break;
180   case TYPE_PLUGIN_INSTANCE:
181     memmove(state->identifier.plugin_instance, buf, LCC_NAME_LEN);
182     break;
183   case TYPE_TYPE:
184     memmove(state->identifier.type, buf, LCC_NAME_LEN);
185     break;
186   case TYPE_TYPE_INSTANCE:
187     memmove(state->identifier.type_instance, buf, LCC_NAME_LEN);
188     break;
189   default:
190     return EINVAL;
191   }
192 
193   return 0;
194 }
195 
parse_time(uint16_t type,void * payload,size_t payload_size,lcc_value_list_t * state)196 static int parse_time(uint16_t type, void *payload, size_t payload_size,
197                       lcc_value_list_t *state) {
198   uint64_t tmp = 0;
199   if (parse_int(payload, payload_size, &tmp))
200     return EINVAL;
201 
202   double t = (double)tmp;
203   switch (type) {
204   case TYPE_INTERVAL:
205     state->interval = t;
206     break;
207   case TYPE_INTERVAL_HR:
208     state->interval = t / 1073741824.0;
209     break;
210   case TYPE_TIME:
211     state->time = t;
212     break;
213   case TYPE_TIME_HR:
214     state->time = t / 1073741824.0;
215     break;
216   default:
217     return EINVAL;
218   }
219 
220   return 0;
221 }
222 
ntohd(double val)223 static double ntohd(double val) /* {{{ */
224 {
225   static int config;
226 
227   union {
228     uint8_t byte[8];
229     double floating;
230   } in = {
231       .floating = val,
232   };
233   union {
234     uint8_t byte[8];
235     double floating;
236   } out = {
237       .byte = {0},
238   };
239 
240   if (config == 0) {
241     double d = 8.642135e130;
242     uint8_t b[8];
243 
244     memcpy(b, &d, sizeof(b));
245 
246     if ((b[0] == 0x2f) && (b[1] == 0x25) && (b[2] == 0xc0) && (b[3] == 0xc7) &&
247         (b[4] == 0x43) && (b[5] == 0x2b) && (b[6] == 0x1f) && (b[7] == 0x5b))
248       config = 1; /* need nothing */
249     else if ((b[7] == 0x2f) && (b[6] == 0x25) && (b[5] == 0xc0) &&
250              (b[4] == 0xc7) && (b[3] == 0x43) && (b[2] == 0x2b) &&
251              (b[1] == 0x1f) && (b[0] == 0x5b))
252       config = 2; /* endian flip */
253     else if ((b[4] == 0x2f) && (b[5] == 0x25) && (b[6] == 0xc0) &&
254              (b[7] == 0xc7) && (b[0] == 0x43) && (b[1] == 0x2b) &&
255              (b[2] == 0x1f) && (b[3] == 0x5b))
256       config = 3; /* int swap */
257     else
258       config = 4;
259   }
260 
261   if (memcmp((char[]){0, 0, 0, 0, 0, 0, 0xf8, 0x7f}, in.byte, 8) == 0) {
262     return NAN;
263   } else if (config == 1) {
264     return val;
265   } else if (config == 2) {
266     in.floating = val;
267     out.byte[0] = in.byte[7];
268     out.byte[1] = in.byte[6];
269     out.byte[2] = in.byte[5];
270     out.byte[3] = in.byte[4];
271     out.byte[4] = in.byte[3];
272     out.byte[5] = in.byte[2];
273     out.byte[6] = in.byte[1];
274     out.byte[7] = in.byte[0];
275     return (out.floating);
276   } else if (config == 3) {
277     in.floating = val;
278     out.byte[0] = in.byte[4];
279     out.byte[1] = in.byte[5];
280     out.byte[2] = in.byte[6];
281     out.byte[3] = in.byte[7];
282     out.byte[4] = in.byte[0];
283     out.byte[5] = in.byte[1];
284     out.byte[6] = in.byte[2];
285     out.byte[7] = in.byte[3];
286     return out.floating;
287   } else {
288     /* If in doubt, just copy the value back to the caller. */
289     return val;
290   }
291 } /* }}} double ntohd */
292 
parse_values(void * payload,size_t payload_size,lcc_value_list_t * state)293 static int parse_values(void *payload, size_t payload_size,
294                         lcc_value_list_t *state) {
295   buffer_t *b = &(buffer_t){
296       .data = payload,
297       .len = payload_size,
298   };
299 
300   uint16_t n;
301   if (buffer_uint16(b, &n))
302     return EINVAL;
303 
304   if (((size_t)n * 9) != b->len)
305     return EINVAL;
306 
307   state->values_len = (size_t)n;
308   state->values = calloc(state->values_len, sizeof(*state->values));
309   state->values_types = calloc(state->values_len, sizeof(*state->values_types));
310   if ((state->values == NULL) || (state->values_types == NULL)) {
311     return ENOMEM;
312   }
313 
314   for (uint16_t i = 0; i < n; i++) {
315     uint8_t tmp;
316     if (buffer_next(b, &tmp, sizeof(tmp)))
317       return EINVAL;
318     state->values_types[i] = (int)tmp;
319   }
320 
321   for (uint16_t i = 0; i < n; i++) {
322     uint64_t tmp;
323     if (buffer_next(b, &tmp, sizeof(tmp)))
324       return EINVAL;
325 
326     if (state->values_types[i] == LCC_TYPE_GAUGE) {
327       union {
328         uint64_t i;
329         double d;
330       } conv = {.i = tmp};
331       state->values[i].gauge = ntohd(conv.d);
332       continue;
333     }
334 
335     tmp = be64toh(tmp);
336     switch (state->values_types[i]) {
337     case LCC_TYPE_COUNTER:
338       state->values[i].counter = (counter_t)tmp;
339       break;
340     case LCC_TYPE_DERIVE:
341       state->values[i].derive = (derive_t)tmp;
342       break;
343     case LCC_TYPE_ABSOLUTE:
344       state->values[i].absolute = (absolute_t)tmp;
345       break;
346     default:
347       return EINVAL;
348     }
349   }
350 
351   return 0;
352 }
353 
354 #if HAVE_GCRYPT_H
verify_sha256(void * payload,size_t payload_size,char const * username,char const * password,uint8_t hash_provided[32])355 static int verify_sha256(void *payload, size_t payload_size,
356                          char const *username, char const *password,
357                          uint8_t hash_provided[32]) {
358   gcry_md_hd_t hd = NULL;
359 
360   gcry_error_t err = gcry_md_open(&hd, GCRY_MD_SHA256, GCRY_MD_FLAG_HMAC);
361   if (err != 0) {
362     return (int)err;
363   }
364 
365   err = gcry_md_setkey(hd, password, strlen(password));
366   if (err != 0) {
367     gcry_md_close(hd);
368     return (int)err;
369   }
370 
371   gcry_md_write(hd, username, strlen(username));
372   gcry_md_write(hd, payload, payload_size);
373 
374   unsigned char *hash_calculated = gcry_md_read(hd, GCRY_MD_SHA256);
375   if (!hash_calculated) {
376     gcry_md_close(hd);
377     return -1;
378   }
379 
380   int ret = memcmp(hash_provided, hash_calculated, 32);
381 
382   gcry_md_close(hd);
383   hash_calculated = NULL;
384 
385   return !!ret;
386 }
387 #else /* !HAVE_GCRYPT_H */
verify_sha256(void * payload,size_t payload_size,char const * username,char const * password,uint8_t hash_provided[32])388 static int verify_sha256(void *payload, size_t payload_size,
389                          char const *username, char const *password,
390                          uint8_t hash_provided[32]) {
391   return ENOTSUP;
392 }
393 #endif
394 
parse_sign_sha256(void * signature,size_t signature_len,void * payload,size_t payload_size,lcc_network_parse_options_t const * opts)395 static int parse_sign_sha256(void *signature, size_t signature_len,
396                              void *payload, size_t payload_size,
397                              lcc_network_parse_options_t const *opts) {
398   if (opts->password_lookup == NULL) {
399     /* The sender signed the packet but we can't verify it. Handle it as if it
400      * were unsigned, i.e. security level NONE. */
401     return network_parse(payload, payload_size, NONE, opts);
402   }
403 
404   buffer_t *b = &(buffer_t){
405       .data = signature,
406       .len = signature_len,
407   };
408 
409   uint8_t hash[32];
410   if (buffer_next(b, hash, sizeof(hash)))
411     return EINVAL;
412 
413   char username[b->len + 1];
414   memset(username, 0, sizeof(username));
415   if (buffer_next(b, username, sizeof(username) - 1)) {
416     return EINVAL;
417   }
418 
419   char const *password = opts->password_lookup(username);
420   if (!password)
421     return network_parse(payload, payload_size, NONE, opts);
422 
423   int status = verify_sha256(payload, payload_size, username, password, hash);
424   if (status != 0)
425     return status;
426 
427   return network_parse(payload, payload_size, SIGN, opts);
428 }
429 
430 #if HAVE_GCRYPT_H
decrypt_aes256(buffer_t * b,void * iv,size_t iv_size,char const * password)431 static int decrypt_aes256(buffer_t *b, void *iv, size_t iv_size,
432                           char const *password) {
433   gcry_cipher_hd_t cipher = NULL;
434 
435   if (gcry_cipher_open(&cipher, GCRY_CIPHER_AES256, GCRY_CIPHER_MODE_OFB,
436                        /* flags = */ 0))
437     return -1;
438 
439   uint8_t pwhash[32] = {0};
440   gcry_md_hash_buffer(GCRY_MD_SHA256, pwhash, password, strlen(password));
441 
442   fprintf(stderr, "sizeof(iv) = %" PRIsz "\n", sizeof(iv));
443   if (gcry_cipher_setkey(cipher, pwhash, sizeof(pwhash)) ||
444       gcry_cipher_setiv(cipher, iv, iv_size) ||
445       gcry_cipher_decrypt(cipher, b->data, b->len, /* in = */ NULL,
446                           /* in_size = */ 0)) {
447     gcry_cipher_close(cipher);
448     return -1;
449   }
450 
451   gcry_cipher_close(cipher);
452   return 0;
453 }
454 
parse_encrypt_aes256(void * data,size_t data_size,lcc_network_parse_options_t const * opts)455 static int parse_encrypt_aes256(void *data, size_t data_size,
456                                 lcc_network_parse_options_t const *opts) {
457   if (opts->password_lookup == NULL) {
458     /* Without a password source it's (hopefully) impossible to decrypt the
459      * network packet. */
460     return ENOENT;
461   }
462 
463   buffer_t *b = &(buffer_t){
464       .data = data,
465       .len = data_size,
466   };
467 
468   uint16_t username_len;
469   if (buffer_uint16(b, &username_len))
470     return EINVAL;
471   if ((size_t)username_len > data_size)
472     return ENOMEM;
473   char username[((size_t)username_len) + 1];
474   memset(username, 0, sizeof(username));
475   if (buffer_next(b, username, (size_t)username_len))
476     return EINVAL;
477 
478   char const *password = opts->password_lookup(username);
479   if (!password)
480     return ENOENT;
481 
482   uint8_t iv[16];
483   if (buffer_next(b, iv, sizeof(iv)))
484     return EINVAL;
485 
486   int status = decrypt_aes256(b, iv, sizeof(iv), password);
487   if (status != 0)
488     return status;
489 
490   uint8_t hash_provided[20];
491   if (buffer_next(b, hash_provided, sizeof(hash_provided))) {
492     return -1;
493   }
494 
495   uint8_t hash_calculated[20];
496   gcry_md_hash_buffer(GCRY_MD_SHA1, hash_calculated, b->data, b->len);
497 
498   if (memcmp(hash_provided, hash_calculated, sizeof(hash_provided)) != 0) {
499     return -1;
500   }
501 
502   return network_parse(b->data, b->len, ENCRYPT, opts);
503 }
504 #else /* !HAVE_GCRYPT_H */
parse_encrypt_aes256(void * data,size_t data_size,lcc_network_parse_options_t const * opts)505 static int parse_encrypt_aes256(void *data, size_t data_size,
506                                 lcc_network_parse_options_t const *opts) {
507   return ENOTSUP;
508 }
509 #endif
510 
network_parse(void * data,size_t data_size,lcc_security_level_t sl,lcc_network_parse_options_t const * opts)511 static int network_parse(void *data, size_t data_size, lcc_security_level_t sl,
512                          lcc_network_parse_options_t const *opts) {
513   buffer_t *b = &(buffer_t){
514       .data = data,
515       .len = data_size,
516   };
517 
518   lcc_value_list_t state = {0};
519 
520   while (b->len > 0) {
521     uint16_t type = 0, sz = 0;
522     if (buffer_uint16(b, &type) || buffer_uint16(b, &sz)) {
523       DEBUG("lcc_network_parse(): reading type and/or length failed.\n");
524       return EINVAL;
525     }
526 
527     if ((sz < 5) || (((size_t)sz - 4) > b->len)) {
528       DEBUG("lcc_network_parse(): invalid 'sz' field: sz = %" PRIu16
529             ", b->len = %" PRIsz "\n",
530             sz, b->len);
531       return EINVAL;
532     }
533     sz -= 4;
534 
535     uint8_t payload[sz];
536     if (buffer_next(b, payload, sizeof(payload)))
537       return EINVAL;
538 
539     switch (type) {
540     case TYPE_HOST:
541     case TYPE_PLUGIN:
542     case TYPE_PLUGIN_INSTANCE:
543     case TYPE_TYPE:
544     case TYPE_TYPE_INSTANCE: {
545       if (parse_identifier(type, payload, sizeof(payload), &state)) {
546         DEBUG("lcc_network_parse(): parse_identifier failed.\n");
547         return EINVAL;
548       }
549       break;
550     }
551 
552     case TYPE_INTERVAL:
553     case TYPE_INTERVAL_HR:
554     case TYPE_TIME:
555     case TYPE_TIME_HR: {
556       if (parse_time(type, payload, sizeof(payload), &state)) {
557         DEBUG("lcc_network_parse(): parse_time failed.\n");
558         return EINVAL;
559       }
560       break;
561     }
562 
563     case TYPE_VALUES: {
564       lcc_value_list_t vl = state;
565       if (parse_values(payload, sizeof(payload), &vl)) {
566         free(vl.values);
567         free(vl.values_types);
568         DEBUG("lcc_network_parse(): parse_values failed.\n");
569         return EINVAL;
570       }
571 
572       int status = 0;
573 
574       /* Write metrics if they have the required security level. */
575       if (sl >= opts->security_level)
576         status = opts->writer(&vl);
577 
578       free(vl.values);
579       free(vl.values_types);
580 
581       if (status != 0)
582         return status;
583       break;
584     }
585 
586     case TYPE_SIGN_SHA256: {
587       int status =
588           parse_sign_sha256(payload, sizeof(payload), b->data, b->len, opts);
589       if (status != 0) {
590         DEBUG("lcc_network_parse(): parse_sign_sha256() = %d\n", status);
591         return -1;
592       }
593       /* parse_sign_sha256, if successful, consumes all remaining data. */
594       b->data = NULL;
595       b->len = 0;
596       break;
597     }
598 
599     case TYPE_ENCR_AES256: {
600       int status = parse_encrypt_aes256(payload, sizeof(payload), opts);
601       if (status != 0) {
602         DEBUG("lcc_network_parse(): parse_encrypt_aes256() = %d\n", status);
603         return -1;
604       }
605       break;
606     }
607 
608     default: {
609       DEBUG("lcc_network_parse(): ignoring unknown type %" PRIu16 "\n", type);
610       return EINVAL;
611     }
612     }
613   }
614 
615   return 0;
616 }
617 
lcc_network_parse(void * data,size_t data_size,lcc_network_parse_options_t opts)618 int lcc_network_parse(void *data, size_t data_size,
619                       lcc_network_parse_options_t opts) {
620   if (opts.password_lookup) {
621 #if HAVE_GCRYPT_H
622     int status;
623     if ((status = init_gcrypt())) {
624       return status;
625     }
626 #else
627     return ENOTSUP;
628 #endif
629   }
630 
631   return network_parse(data, data_size, NONE, &opts);
632 }
633