| 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 | } |