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5024c2ac JR |
1 | /* |
2 | * Copyright (C) 2019 Jonathan Rajotte <jonathan.rajotte-julien@efficios.com> | |
3 | * | |
4 | * SPDX-License-Identifier: LGPL-2.1-only | |
5 | * | |
6 | */ | |
7 | ||
8 | #include <assert.h> | |
9 | #include <common/error.h> | |
10 | #include <common/macros.h> | |
11 | #include <common/runas.h> | |
12 | #include <lttng/event-rule/event-rule-internal.h> | |
13 | #include <lttng/event-rule/syscall-internal.h> | |
14 | ||
15 | #define IS_SYSCALL_EVENT_RULE(rule) \ | |
16 | (lttng_event_rule_get_type(rule) == LTTNG_EVENT_RULE_TYPE_SYSCALL) | |
17 | ||
18 | static void lttng_event_rule_syscall_destroy(struct lttng_event_rule *rule) | |
19 | { | |
20 | struct lttng_event_rule_syscall *syscall; | |
21 | ||
22 | if (rule == NULL) { | |
23 | return; | |
24 | } | |
25 | ||
26 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
27 | ||
28 | free(syscall->pattern); | |
29 | free(syscall->filter_expression); | |
30 | free(syscall->internal_filter.filter); | |
31 | free(syscall->internal_filter.bytecode); | |
32 | free(syscall); | |
33 | } | |
34 | ||
35 | static bool lttng_event_rule_syscall_validate( | |
36 | const struct lttng_event_rule *rule) | |
37 | { | |
38 | bool valid = false; | |
39 | struct lttng_event_rule_syscall *syscall; | |
40 | ||
41 | if (!rule) { | |
42 | goto end; | |
43 | } | |
44 | ||
45 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
46 | ||
47 | /* Required field */ | |
48 | if (!syscall->pattern) { | |
49 | ERR("Invalid syscall event rule: a pattern must be set."); | |
50 | goto end; | |
51 | } | |
52 | ||
53 | valid = true; | |
54 | end: | |
55 | return valid; | |
56 | } | |
57 | ||
58 | static int lttng_event_rule_syscall_serialize( | |
59 | const struct lttng_event_rule *rule, | |
60 | struct lttng_dynamic_buffer *buf, | |
61 | int *fd_to_send) | |
62 | { | |
63 | int ret; | |
64 | size_t pattern_len, filter_expression_len; | |
65 | struct lttng_event_rule_syscall *syscall; | |
66 | struct lttng_event_rule_syscall_comm syscall_comm; | |
67 | ||
68 | if (!rule || !IS_SYSCALL_EVENT_RULE(rule)) { | |
69 | ret = -1; | |
70 | goto end; | |
71 | } | |
72 | ||
73 | DBG("Serializing syscall event rule"); | |
74 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
75 | ||
76 | pattern_len = strlen(syscall->pattern) + 1; | |
77 | ||
78 | if (syscall->filter_expression != NULL) { | |
79 | filter_expression_len = strlen(syscall->filter_expression) + 1; | |
80 | } else { | |
81 | filter_expression_len = 0; | |
82 | } | |
83 | ||
84 | syscall_comm.pattern_len = pattern_len; | |
85 | syscall_comm.filter_expression_len = filter_expression_len; | |
86 | ||
87 | ret = lttng_dynamic_buffer_append( | |
88 | buf, &syscall_comm, sizeof(syscall_comm)); | |
89 | if (ret) { | |
90 | goto end; | |
91 | } | |
92 | ret = lttng_dynamic_buffer_append(buf, syscall->pattern, pattern_len); | |
93 | if (ret) { | |
94 | goto end; | |
95 | } | |
96 | ret = lttng_dynamic_buffer_append( | |
97 | buf, syscall->filter_expression, filter_expression_len); | |
98 | if (ret) { | |
99 | goto end; | |
100 | } | |
101 | ||
102 | if (fd_to_send) { | |
103 | /* Nothing to send */ | |
104 | *fd_to_send = -1; | |
105 | } | |
106 | end: | |
107 | return ret; | |
108 | } | |
109 | ||
110 | static bool lttng_event_rule_syscall_is_equal(const struct lttng_event_rule *_a, | |
111 | const struct lttng_event_rule *_b) | |
112 | { | |
113 | bool is_equal = false; | |
114 | struct lttng_event_rule_syscall *a, *b; | |
115 | ||
116 | a = container_of(_a, struct lttng_event_rule_syscall, parent); | |
117 | b = container_of(_b, struct lttng_event_rule_syscall, parent); | |
118 | ||
119 | if (!!a->filter_expression != !!b->filter_expression) { | |
120 | goto end; | |
121 | } | |
122 | ||
123 | /* Long check */ | |
124 | /* syscall is invalid if this is not true */ | |
125 | assert(a->pattern); | |
126 | assert(b->pattern); | |
127 | if (strcmp(a->pattern, b->pattern)) { | |
128 | goto end; | |
129 | } | |
130 | ||
131 | if (a->filter_expression && b->filter_expression) { | |
132 | if (strcmp(a->filter_expression, b->filter_expression)) { | |
133 | goto end; | |
134 | } | |
135 | } | |
136 | ||
137 | is_equal = true; | |
138 | end: | |
139 | return is_equal; | |
140 | } | |
141 | ||
142 | static enum lttng_error_code lttng_event_rule_syscall_populate( | |
143 | struct lttng_event_rule *rule, uid_t uid, gid_t gid) | |
144 | { | |
145 | int ret; | |
146 | enum lttng_error_code ret_code = LTTNG_OK; | |
147 | struct lttng_event_rule_syscall *syscall; | |
148 | enum lttng_event_rule_status status; | |
149 | const char *filter; | |
150 | struct lttng_bytecode *bytecode = NULL; | |
151 | ||
152 | assert(rule); | |
153 | ||
154 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
155 | ||
156 | /* Generate the filter bytecode */ | |
157 | status = lttng_event_rule_syscall_get_filter(rule, &filter); | |
158 | if (status == LTTNG_EVENT_RULE_STATUS_UNSET) { | |
159 | filter = NULL; | |
160 | } else if (status != LTTNG_EVENT_RULE_STATUS_OK) { | |
161 | ret_code = LTTNG_ERR_FILTER_INVAL; | |
162 | goto end; | |
163 | } | |
164 | ||
165 | if (filter && filter[0] == '\0') { | |
166 | ret_code = LTTNG_ERR_FILTER_INVAL; | |
167 | goto error; | |
168 | } | |
169 | ||
170 | if (filter == NULL) { | |
171 | /* Nothing to do */ | |
172 | ret = LTTNG_OK; | |
173 | goto end; | |
174 | } | |
175 | ||
176 | syscall->internal_filter.filter = strdup(filter); | |
177 | if (syscall->internal_filter.filter == NULL) { | |
178 | ret_code = LTTNG_ERR_NOMEM; | |
179 | goto end; | |
180 | } | |
181 | ||
182 | ret = run_as_generate_filter_bytecode( | |
183 | syscall->internal_filter.filter, uid, gid, &bytecode); | |
184 | if (ret) { | |
185 | ret_code = LTTNG_ERR_FILTER_INVAL; | |
186 | } | |
187 | ||
188 | syscall->internal_filter.bytecode = bytecode; | |
189 | bytecode = NULL; | |
190 | ||
191 | error: | |
192 | end: | |
193 | free(bytecode); | |
194 | return ret_code; | |
195 | } | |
196 | ||
197 | static const char *lttng_event_rule_syscall_get_internal_filter( | |
198 | const struct lttng_event_rule *rule) | |
199 | { | |
200 | struct lttng_event_rule_syscall *syscall; | |
201 | assert(rule); | |
202 | ||
203 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
204 | return syscall->internal_filter.filter; | |
205 | } | |
206 | ||
207 | static const struct lttng_bytecode * | |
208 | lttng_event_rule_syscall_get_internal_filter_bytecode( | |
209 | const struct lttng_event_rule *rule) | |
210 | { | |
211 | struct lttng_event_rule_syscall *syscall; | |
212 | assert(rule); | |
213 | ||
214 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
215 | return syscall->internal_filter.bytecode; | |
216 | } | |
217 | ||
218 | static struct lttng_event_exclusion * | |
219 | lttng_event_rule_syscall_generate_exclusions(struct lttng_event_rule *rule) | |
220 | { | |
221 | /* Not supported */ | |
222 | return NULL; | |
223 | } | |
224 | ||
225 | struct lttng_event_rule *lttng_event_rule_syscall_create() | |
226 | { | |
227 | struct lttng_event_rule_syscall *rule; | |
228 | ||
229 | rule = zmalloc(sizeof(struct lttng_event_rule_syscall)); | |
230 | if (!rule) { | |
231 | return NULL; | |
232 | } | |
233 | ||
234 | lttng_event_rule_init(&rule->parent, LTTNG_EVENT_RULE_TYPE_SYSCALL); | |
235 | rule->parent.validate = lttng_event_rule_syscall_validate; | |
236 | rule->parent.serialize = lttng_event_rule_syscall_serialize; | |
237 | rule->parent.equal = lttng_event_rule_syscall_is_equal; | |
238 | rule->parent.destroy = lttng_event_rule_syscall_destroy; | |
239 | rule->parent.populate = lttng_event_rule_syscall_populate; | |
240 | rule->parent.get_filter = lttng_event_rule_syscall_get_internal_filter; | |
241 | rule->parent.get_filter_bytecode = | |
242 | lttng_event_rule_syscall_get_internal_filter_bytecode; | |
243 | rule->parent.generate_exclusions = | |
244 | lttng_event_rule_syscall_generate_exclusions; | |
245 | return &rule->parent; | |
246 | } | |
247 | ||
248 | LTTNG_HIDDEN | |
249 | ssize_t lttng_event_rule_syscall_create_from_buffer( | |
250 | const struct lttng_buffer_view *view, | |
251 | struct lttng_event_rule **_event_rule) | |
252 | { | |
253 | ssize_t ret, offset = 0; | |
254 | enum lttng_event_rule_status status; | |
255 | const struct lttng_event_rule_syscall_comm *syscall_comm; | |
256 | const char *pattern; | |
257 | const char *filter_expression = NULL; | |
258 | struct lttng_buffer_view current_view; | |
259 | struct lttng_event_rule *rule = NULL; | |
260 | ||
261 | if (!_event_rule) { | |
262 | ret = -1; | |
263 | goto end; | |
264 | } | |
265 | ||
266 | if (view->size < sizeof(*syscall_comm)) { | |
267 | ERR("Failed to initialize from malformed event rule syscall: buffer too short to contain header"); | |
268 | ret = -1; | |
269 | goto end; | |
270 | } | |
271 | ||
272 | current_view = lttng_buffer_view_from_view( | |
273 | view, offset, sizeof(*syscall_comm)); | |
274 | syscall_comm = (typeof(syscall_comm)) current_view.data; | |
275 | ||
276 | if (!syscall_comm) { | |
277 | ret = -1; | |
278 | goto end; | |
279 | } | |
280 | ||
281 | rule = lttng_event_rule_syscall_create(); | |
282 | if (!rule) { | |
283 | ERR("Failed to create event rule syscall"); | |
284 | ret = -1; | |
285 | goto end; | |
286 | } | |
287 | ||
288 | /* Skip to payload */ | |
289 | offset += current_view.size; | |
290 | ||
291 | /* Map the pattern */ | |
292 | current_view = lttng_buffer_view_from_view( | |
293 | view, offset, syscall_comm->pattern_len); | |
294 | pattern = current_view.data; | |
295 | if (!pattern) { | |
296 | ret = -1; | |
297 | goto end; | |
298 | } | |
299 | ||
300 | if (syscall_comm->pattern_len == 1 || | |
301 | pattern[syscall_comm->pattern_len - 1] != '\0' || | |
302 | strlen(pattern) != syscall_comm->pattern_len - 1) { | |
303 | /* | |
304 | * Check that the pattern is not NULL, is NULL-terminated, and | |
305 | * does not contain a NULL before the last byte. | |
306 | */ | |
307 | ret = -1; | |
308 | goto end; | |
309 | } | |
310 | ||
311 | /* Skip after the pattern */ | |
312 | offset += syscall_comm->pattern_len; | |
313 | ||
314 | if (!syscall_comm->filter_expression_len) { | |
315 | goto skip_filter_expression; | |
316 | } | |
317 | ||
318 | /* Map the filter_expression */ | |
319 | current_view = lttng_buffer_view_from_view( | |
320 | view, offset, syscall_comm->filter_expression_len); | |
321 | filter_expression = current_view.data; | |
322 | if (!filter_expression) { | |
323 | ret = -1; | |
324 | goto end; | |
325 | } | |
326 | ||
327 | if (syscall_comm->filter_expression_len == 1 || | |
328 | filter_expression[syscall_comm->filter_expression_len - | |
329 | 1] != '\0' || | |
330 | strlen(filter_expression) != | |
331 | syscall_comm->filter_expression_len - | |
332 | 1) { | |
333 | /* | |
334 | * Check that the filter expression is not NULL, is | |
335 | * NULL-terminated, and does not contain a NULL before the last | |
336 | * byte. | |
337 | */ | |
338 | ret = -1; | |
339 | goto end; | |
340 | } | |
341 | ||
342 | /* Skip after the pattern */ | |
343 | offset += syscall_comm->filter_expression_len; | |
344 | ||
345 | skip_filter_expression: | |
346 | ||
347 | status = lttng_event_rule_syscall_set_pattern(rule, pattern); | |
348 | if (status != LTTNG_EVENT_RULE_STATUS_OK) { | |
349 | ERR("Failed to set event rule syscall pattern"); | |
350 | ret = -1; | |
351 | goto end; | |
352 | } | |
353 | ||
354 | if (filter_expression) { | |
355 | status = lttng_event_rule_syscall_set_filter( | |
356 | rule, filter_expression); | |
357 | if (status != LTTNG_EVENT_RULE_STATUS_OK) { | |
358 | ERR("Failed to set event rule syscall pattern"); | |
359 | ret = -1; | |
360 | goto end; | |
361 | } | |
362 | } | |
363 | ||
364 | *_event_rule = rule; | |
365 | rule = NULL; | |
366 | ret = offset; | |
367 | end: | |
368 | lttng_event_rule_destroy(rule); | |
369 | return ret; | |
370 | } | |
371 | ||
372 | enum lttng_event_rule_status lttng_event_rule_syscall_set_pattern( | |
373 | struct lttng_event_rule *rule, const char *pattern) | |
374 | { | |
375 | char *pattern_copy = NULL; | |
376 | struct lttng_event_rule_syscall *syscall; | |
377 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
378 | ||
379 | if (!rule || !IS_SYSCALL_EVENT_RULE(rule) || !pattern || | |
380 | strlen(pattern) == 0) { | |
381 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
382 | goto end; | |
383 | } | |
384 | ||
385 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
386 | pattern_copy = strdup(pattern); | |
387 | if (!pattern_copy) { | |
388 | status = LTTNG_EVENT_RULE_STATUS_ERROR; | |
389 | goto end; | |
390 | } | |
391 | ||
392 | if (syscall->pattern) { | |
393 | free(syscall->pattern); | |
394 | } | |
395 | ||
396 | syscall->pattern = pattern_copy; | |
397 | pattern_copy = NULL; | |
398 | end: | |
399 | return status; | |
400 | } | |
401 | ||
402 | enum lttng_event_rule_status lttng_event_rule_syscall_get_pattern( | |
403 | const struct lttng_event_rule *rule, const char **pattern) | |
404 | { | |
405 | struct lttng_event_rule_syscall *syscall; | |
406 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
407 | ||
408 | if (!rule || !IS_SYSCALL_EVENT_RULE(rule) || !pattern) { | |
409 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
410 | goto end; | |
411 | } | |
412 | ||
413 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
414 | if (!syscall->pattern) { | |
415 | status = LTTNG_EVENT_RULE_STATUS_UNSET; | |
416 | goto end; | |
417 | } | |
418 | ||
419 | *pattern = syscall->pattern; | |
420 | end: | |
421 | return status; | |
422 | } | |
423 | ||
424 | enum lttng_event_rule_status lttng_event_rule_syscall_set_filter( | |
425 | struct lttng_event_rule *rule, const char *expression) | |
426 | { | |
427 | char *expression_copy = NULL; | |
428 | struct lttng_event_rule_syscall *syscall; | |
429 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
430 | ||
431 | /* TODO: validate that the passed expression is valid */ | |
432 | ||
433 | if (!rule || !IS_SYSCALL_EVENT_RULE(rule) || !expression || | |
434 | strlen(expression) == 0) { | |
435 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
436 | goto end; | |
437 | } | |
438 | ||
439 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
440 | expression_copy = strdup(expression); | |
441 | if (!expression_copy) { | |
442 | status = LTTNG_EVENT_RULE_STATUS_ERROR; | |
443 | goto end; | |
444 | } | |
445 | ||
446 | if (syscall->filter_expression) { | |
447 | free(syscall->filter_expression); | |
448 | } | |
449 | ||
450 | syscall->filter_expression = expression_copy; | |
451 | expression_copy = NULL; | |
452 | end: | |
453 | return status; | |
454 | } | |
455 | ||
456 | enum lttng_event_rule_status lttng_event_rule_syscall_get_filter( | |
457 | const struct lttng_event_rule *rule, const char **expression) | |
458 | { | |
459 | struct lttng_event_rule_syscall *syscall; | |
460 | enum lttng_event_rule_status status = LTTNG_EVENT_RULE_STATUS_OK; | |
461 | ||
462 | if (!rule || !IS_SYSCALL_EVENT_RULE(rule) || !expression) { | |
463 | status = LTTNG_EVENT_RULE_STATUS_INVALID; | |
464 | goto end; | |
465 | } | |
466 | ||
467 | syscall = container_of(rule, struct lttng_event_rule_syscall, parent); | |
468 | if (!syscall->filter_expression) { | |
469 | status = LTTNG_EVENT_RULE_STATUS_UNSET; | |
470 | goto end; | |
471 | } | |
472 | ||
473 | *expression = syscall->filter_expression; | |
474 | end: | |
475 | return status; | |
476 | } |