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