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d3a684ee JR |
1 | /* |
2 | * Copyright (C) 2019 - Jonathan Rajotte-Julien <jonathan.rajotte-julien@efficios.com> | |
3 | * | |
4 | * This library is free software; you can redistribute it and/or modify it | |
5 | * under the terms of the GNU Lesser General Public License, version 2.1 only, | |
6 | * as published by the Free Software Foundation. | |
7 | * | |
8 | * This library is distributed in the hope that it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License | |
11 | * for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU Lesser General Public License | |
14 | * along with this library; if not, write to the Free Software Foundation, | |
15 | * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
16 | */ | |
17 | ||
18 | #include <lttng/event-rule/event-rule-internal.h> | |
19 | #include <lttng/event-rule/syscall-internal.h> | |
20 | #include <common/macros.h> | |
21 | #include <common/error.h> | |
22 | #include <common/runas.h> | |
23 | #include <assert.h> | |
24 | ||
25 | #define IS_SYSCALL_EVENT_RULE(rule) ( \ | |
26 | lttng_event_rule_get_type(rule) == LTTNG_EVENT_RULE_TYPE_SYSCALL \ | |
27 | ) | |
28 | ||
29 | static | |
30 | void lttng_event_rule_syscall_destroy(struct lttng_event_rule *rule) | |
31 | { | |
32 | struct lttng_event_rule_syscall *syscall; | |
33 | ||
34 | if (rule == NULL) { | |
35 | return; | |
36 | } | |
37 | ||
38 | syscall = container_of(rule, struct lttng_event_rule_syscall, | |
39 | parent); | |
40 | ||
41 | free(syscall->pattern); | |
42 | free(syscall->filter_expression); | |
43 | free(syscall->internal_filter.filter); | |
44 | free(syscall->internal_filter.bytecode); | |
45 | free(syscall); | |
46 | } | |
47 | ||
48 | static | |
49 | bool lttng_event_rule_syscall_validate( | |
50 | const struct lttng_event_rule *rule) | |
51 | { | |
52 | bool valid = false; | |
53 | struct lttng_event_rule_syscall *syscall; | |
54 | ||
55 | if (!rule) { | |
56 | goto end; | |
57 | } | |
58 | ||
59 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
60 | ||
61 | /* Required field */ | |
62 | if (!syscall->pattern) { | |
63 | ERR("Invalid syscall event rule: a pattern must be set."); | |
64 | goto end; | |
65 | } | |
66 | ||
67 | valid = true; | |
68 | end: | |
69 | return valid; | |
70 | } | |
71 | ||
72 | static | |
73 | int lttng_event_rule_syscall_serialize( | |
74 | const struct lttng_event_rule *rule, | |
75 | struct lttng_dynamic_buffer *buf, | |
76 | int *fd_to_send) | |
77 | { | |
78 | int ret; | |
79 | size_t pattern_len, filter_expression_len; | |
80 | struct lttng_event_rule_syscall *syscall; | |
81 | struct lttng_event_rule_syscall_comm syscall_comm; | |
82 | ||
83 | if (!rule || !IS_SYSCALL_EVENT_RULE(rule)) { | |
84 | ret = -1; | |
85 | goto end; | |
86 | } | |
87 | ||
88 | DBG("Serializing syscall event rule"); | |
89 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
90 | ||
91 | pattern_len = strlen(syscall->pattern) + 1; | |
92 | ||
93 | if (syscall->filter_expression != NULL) { | |
94 | filter_expression_len = strlen(syscall->filter_expression) + 1; | |
95 | } else { | |
96 | filter_expression_len = 0; | |
97 | } | |
98 | ||
99 | syscall_comm.pattern_len = pattern_len; | |
100 | syscall_comm.filter_expression_len = filter_expression_len; | |
101 | ||
102 | ret = lttng_dynamic_buffer_append( | |
103 | buf, &syscall_comm, sizeof(syscall_comm)); | |
104 | if (ret) { | |
105 | goto end; | |
106 | } | |
107 | ret = lttng_dynamic_buffer_append(buf, syscall->pattern, pattern_len); | |
108 | if (ret) { | |
109 | goto end; | |
110 | } | |
111 | ret = lttng_dynamic_buffer_append( | |
112 | buf, syscall->filter_expression, filter_expression_len); | |
113 | if (ret) { | |
114 | goto end; | |
115 | } | |
116 | ||
117 | if (fd_to_send) { | |
118 | /* Nothing to send */ | |
119 | *fd_to_send = -1; | |
120 | } | |
121 | end: | |
122 | return ret; | |
123 | } | |
124 | ||
125 | static | |
126 | bool lttng_event_rule_syscall_is_equal(const struct lttng_event_rule *_a, | |
127 | const struct lttng_event_rule *_b) | |
128 | { | |
129 | bool is_equal = false; | |
130 | struct lttng_event_rule_syscall *a, *b; | |
131 | ||
132 | a = container_of(_a, struct lttng_event_rule_syscall, parent); | |
133 | b = container_of(_b, struct lttng_event_rule_syscall, parent); | |
134 | ||
135 | if (!!a->filter_expression != !!b->filter_expression) { | |
136 | goto end; | |
137 | } | |
138 | ||
139 | /* Long check */ | |
140 | /* syscall is invalid if this is not true */ | |
141 | assert(a->pattern); | |
142 | assert(b->pattern); | |
143 | if (strcmp(a->pattern, b->pattern)) { | |
144 | goto end; | |
145 | } | |
146 | ||
147 | if (a->filter_expression && b->filter_expression) { | |
148 | if (strcmp(a->filter_expression, b->filter_expression)) { | |
149 | goto end; | |
150 | } | |
151 | } | |
152 | ||
153 | is_equal = true; | |
154 | end: | |
155 | return is_equal; | |
156 | } | |
157 | ||
158 | static | |
159 | enum lttng_error_code lttng_event_rule_syscall_populate(struct lttng_event_rule *rule, uid_t uid, gid_t gid) | |
160 | { | |
161 | int ret; | |
162 | enum lttng_error_code ret_code = LTTNG_OK; | |
163 | struct lttng_event_rule_syscall *syscall; | |
164 | enum lttng_event_rule_status status; | |
165 | const char *filter; | |
166 | struct lttng_filter_bytecode *bytecode = NULL; | |
167 | ||
168 | assert(rule); | |
169 | ||
170 | syscall = container_of(rule, struct lttng_event_rule_syscall, | |
171 | parent); | |
172 | ||
173 | /* Generate the filter bytecode */ | |
174 | status = lttng_event_rule_syscall_get_filter(rule, &filter); | |
175 | if (status == LTTNG_EVENT_RULE_STATUS_UNSET) { | |
176 | filter = NULL; | |
177 | } else if (status != LTTNG_EVENT_RULE_STATUS_OK) { | |
178 | ret_code = LTTNG_ERR_FILTER_INVAL; | |
179 | goto end; | |
180 | } | |
181 | ||
182 | if (filter && filter[0] == '\0') { | |
183 | ret_code = LTTNG_ERR_FILTER_INVAL; | |
184 | goto error; | |
185 | } | |
186 | ||
187 | if (filter == NULL) { | |
188 | /* Nothing to do */ | |
189 | ret = LTTNG_OK; | |
190 | goto end; | |
191 | } | |
192 | ||
193 | syscall->internal_filter.filter = strdup(filter); | |
194 | if (syscall->internal_filter.filter == NULL) { | |
195 | ret_code = LTTNG_ERR_NOMEM; | |
196 | goto end; | |
197 | } | |
198 | ||
199 | ret = run_as_generate_filter_bytecode(syscall->internal_filter.filter, uid, gid, &bytecode); | |
200 | if (ret) { | |
201 | ret_code = LTTNG_ERR_FILTER_INVAL; | |
202 | } | |
203 | ||
204 | syscall->internal_filter.bytecode = bytecode; | |
205 | bytecode = NULL; | |
206 | ||
207 | error: | |
208 | end: | |
209 | free(bytecode); | |
210 | return ret_code; | |
211 | } | |
212 | ||
213 | static const char *lttng_event_rule_syscall_get_internal_filter( | |
214 | const struct lttng_event_rule *rule) | |
215 | { | |
216 | struct lttng_event_rule_syscall *syscall; | |
217 | assert(rule); | |
218 | ||
219 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
220 | return syscall->internal_filter.filter; | |
221 | } | |
222 | ||
223 | static const struct lttng_filter_bytecode * | |
224 | lttng_event_rule_syscall_get_internal_filter_bytecode( | |
225 | const struct lttng_event_rule *rule) | |
226 | { | |
227 | struct lttng_event_rule_syscall *syscall; | |
228 | assert(rule); | |
229 | ||
230 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
231 | return syscall->internal_filter.bytecode; | |
232 | } | |
233 | ||
234 | static struct lttng_event_exclusion * | |
235 | lttng_event_rule_syscall_generate_exclusions(struct lttng_event_rule *rule) | |
236 | { | |
237 | /* Not supported */ | |
238 | return NULL; | |
239 | } | |
240 | ||
241 | struct lttng_event_rule *lttng_event_rule_syscall_create() | |
242 | { | |
243 | struct lttng_event_rule_syscall *rule; | |
244 | ||
245 | rule = zmalloc(sizeof(struct lttng_event_rule_syscall)); | |
246 | if (!rule) { | |
247 | return NULL; | |
248 | } | |
249 | ||
250 | lttng_event_rule_init(&rule->parent, LTTNG_EVENT_RULE_TYPE_SYSCALL); | |
251 | rule->parent.validate = lttng_event_rule_syscall_validate; | |
252 | rule->parent.serialize = lttng_event_rule_syscall_serialize; | |
253 | rule->parent.equal = lttng_event_rule_syscall_is_equal; | |
254 | rule->parent.destroy = lttng_event_rule_syscall_destroy; | |
255 | rule->parent.populate = lttng_event_rule_syscall_populate; | |
256 | rule->parent.get_filter = lttng_event_rule_syscall_get_internal_filter; | |
257 | rule->parent.get_filter_bytecode = | |
258 | lttng_event_rule_syscall_get_internal_filter_bytecode; | |
259 | rule->parent.generate_exclusions = | |
260 | lttng_event_rule_syscall_generate_exclusions; | |
261 | return &rule->parent; | |
262 | } | |
263 | ||
264 | LTTNG_HIDDEN | |
265 | ssize_t lttng_event_rule_syscall_create_from_buffer( | |
266 | const struct lttng_buffer_view *view, | |
267 | struct lttng_event_rule **_event_rule) | |
268 | { | |
269 | ssize_t ret, offset = 0; | |
270 | enum lttng_event_rule_status status; | |
271 | const struct lttng_event_rule_syscall_comm *syscall_comm; | |
272 | const char *pattern; | |
273 | const char *filter_expression = NULL; | |
274 | struct lttng_buffer_view current_view; | |
275 | struct lttng_event_rule *rule = NULL; | |
276 | ||
277 | if (!_event_rule) { | |
278 | ret = -1; | |
279 | goto end; | |
280 | } | |
281 | ||
282 | if (view->size < sizeof(*syscall_comm)) { | |
283 | ERR("Failed to initialize from malformed event rule syscall: buffer too short to contain header"); | |
284 | ret = -1; | |
285 | goto end; | |
286 | } | |
287 | ||
288 | current_view = lttng_buffer_view_from_view( | |
289 | view, offset, sizeof(*syscall_comm)); | |
290 | syscall_comm = (typeof(syscall_comm)) current_view.data; | |
291 | ||
292 | if (!syscall_comm) { | |
293 | ret = -1; | |
294 | goto end; | |
295 | } | |
296 | ||
297 | rule = lttng_event_rule_syscall_create(); | |
298 | if (!rule) { | |
299 | ERR("Failed to create event rule syscall"); | |
300 | ret = -1; | |
301 | goto end; | |
302 | } | |
303 | ||
304 | /* Skip to payload */ | |
305 | offset += current_view.size; | |
306 | ||
307 | /* Map the pattern */ | |
308 | current_view = lttng_buffer_view_from_view( | |
309 | view, offset, syscall_comm->pattern_len); | |
310 | pattern = current_view.data; | |
311 | if (!pattern) { | |
312 | ret = -1; | |
313 | goto end; | |
314 | } | |
315 | ||
316 | if (syscall_comm->pattern_len == 1 || | |
317 | pattern[syscall_comm->pattern_len - 1] != '\0' || | |
318 | strlen(pattern) != syscall_comm->pattern_len - 1) { | |
319 | /* | |
320 | * Check that the pattern is not NULL, is NULL-terminated, and | |
321 | * does not contain a NULL before the last byte. | |
322 | */ | |
323 | ret = -1; | |
324 | goto end; | |
325 | } | |
326 | ||
327 | /* Skip after the pattern */ | |
328 | offset += syscall_comm->pattern_len; | |
329 | ||
330 | if (!syscall_comm->filter_expression_len) { | |
331 | goto skip_filter_expression; | |
332 | } | |
333 | ||
334 | /* Map the filter_expression */ | |
335 | current_view = lttng_buffer_view_from_view( | |
336 | view, offset, syscall_comm->filter_expression_len); | |
337 | filter_expression = current_view.data; | |
338 | if (!filter_expression) { | |
339 | ret = -1; | |
340 | goto end; | |
341 | } | |
342 | ||
343 | if (syscall_comm->filter_expression_len == 1 || | |
344 | filter_expression[syscall_comm->filter_expression_len - | |
345 | 1] != '\0' || | |
346 | strlen(filter_expression) != | |
347 | syscall_comm->filter_expression_len - | |
348 | 1) { | |
349 | /* | |
350 | * Check that the filter expression is not NULL, is | |
351 | * NULL-terminated, and does not contain a NULL before the last | |
352 | * byte. | |
353 | */ | |
354 | ret = -1; | |
355 | goto end; | |
356 | } | |
357 | ||
358 | /* Skip after the pattern */ | |
359 | offset += syscall_comm->filter_expression_len; | |
360 | ||
361 | skip_filter_expression: | |
362 | ||
363 | status = lttng_event_rule_syscall_set_pattern(rule, pattern); | |
364 | if (status != LTTNG_EVENT_RULE_STATUS_OK) { | |
365 | ERR("Failed to set event rule syscall pattern"); | |
366 | ret = -1; | |
367 | goto end; | |
368 | } | |
369 | ||
370 | if (filter_expression) { | |
371 | status = lttng_event_rule_syscall_set_filter( | |
372 | rule, filter_expression); | |
373 | if (status != LTTNG_EVENT_RULE_STATUS_OK) { | |
374 | ERR("Failed to set event rule syscall pattern"); | |
375 | ret = -1; | |
376 | goto end; | |
377 | } | |
378 | } | |
379 | ||
380 | *_event_rule = rule; | |
381 | rule = NULL; | |
382 | ret = offset; | |
383 | end: | |
384 | lttng_event_rule_destroy(rule); | |
385 | return ret; | |
386 | } | |
387 | ||
388 | enum lttng_event_rule_status lttng_event_rule_syscall_set_pattern( | |
389 | struct lttng_event_rule *rule, const char *pattern) | |
390 | { | |
391 | char *pattern_copy = NULL; | |
392 | struct lttng_event_rule_syscall *syscall; | |
393 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
394 | ||
395 | if (!rule || !IS_SYSCALL_EVENT_RULE(rule) || !pattern || | |
396 | strlen(pattern) == 0) { | |
397 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
398 | goto end; | |
399 | } | |
400 | ||
401 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
402 | pattern_copy = strdup(pattern); | |
403 | if (!pattern_copy) { | |
404 | status = LTTNG_EVENT_RULE_STATUS_ERROR; | |
405 | goto end; | |
406 | } | |
407 | ||
408 | if (syscall->pattern) { | |
409 | free(syscall->pattern); | |
410 | } | |
411 | ||
412 | syscall->pattern = pattern_copy; | |
413 | pattern_copy = NULL; | |
414 | end: | |
415 | return status; | |
416 | } | |
417 | ||
418 | enum lttng_event_rule_status lttng_event_rule_syscall_get_pattern( | |
419 | const struct lttng_event_rule *rule, const char **pattern) | |
420 | { | |
421 | struct lttng_event_rule_syscall *syscall; | |
422 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
423 | ||
424 | if (!rule || !IS_SYSCALL_EVENT_RULE(rule) || !pattern) { | |
425 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
426 | goto end; | |
427 | } | |
428 | ||
429 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
430 | if (!syscall->pattern) { | |
431 | status = LTTNG_EVENT_RULE_STATUS_UNSET; | |
432 | goto end; | |
433 | } | |
434 | ||
435 | *pattern = syscall->pattern; | |
436 | end: | |
437 | return status; | |
438 | } | |
439 | ||
440 | enum lttng_event_rule_status lttng_event_rule_syscall_set_filter( | |
441 | struct lttng_event_rule *rule, const char *expression) | |
442 | { | |
443 | char *expression_copy = NULL; | |
444 | struct lttng_event_rule_syscall *syscall; | |
445 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
446 | ||
447 | /* TODO: validate that the passed expression is valid */ | |
448 | ||
449 | if (!rule || !IS_SYSCALL_EVENT_RULE(rule) || !expression || | |
450 | strlen(expression) == 0) { | |
451 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
452 | goto end; | |
453 | } | |
454 | ||
455 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
456 | expression_copy = strdup(expression); | |
457 | if (!expression_copy) { | |
458 | status = LTTNG_EVENT_RULE_STATUS_ERROR; | |
459 | goto end; | |
460 | } | |
461 | ||
462 | if (syscall->filter_expression) { | |
463 | free(syscall->filter_expression); | |
464 | } | |
465 | ||
466 | syscall->filter_expression = expression_copy; | |
467 | expression_copy = NULL; | |
468 | end: | |
469 | return status; | |
470 | } | |
471 | ||
472 | enum lttng_event_rule_status lttng_event_rule_syscall_get_filter( | |
473 | const struct lttng_event_rule *rule, const char **expression) | |
474 | { | |
475 | struct lttng_event_rule_syscall *syscall; | |
476 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
477 | ||
478 | if (!rule || !IS_SYSCALL_EVENT_RULE(rule) || !expression) { | |
479 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
480 | goto end; | |
481 | } | |
482 | ||
483 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
484 | if (!syscall->filter_expression) { | |
485 | status = LTTNG_EVENT_RULE_STATUS_UNSET; | |
486 | goto end; | |
487 | } | |
488 | ||
489 | *expression = syscall->filter_expression; | |
490 | end: | |
491 | return status; | |
492 | } |