| 1 | /* |
| 2 | * lttng-filter-validator.c |
| 3 | * |
| 4 | * LTTng modules filter bytecode validator. |
| 5 | * |
| 6 | * Copyright (C) 2010-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 7 | * |
| 8 | * This library is free software; you can redistribute it and/or |
| 9 | * modify it under the terms of the GNU Lesser General Public |
| 10 | * License as published by the Free Software Foundation; only |
| 11 | * version 2.1 of the License. |
| 12 | * |
| 13 | * This library is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 16 | * Lesser General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU Lesser General Public |
| 19 | * License along with this library; if not, write to the Free Software |
| 20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 21 | */ |
| 22 | |
| 23 | #include <linux/types.h> |
| 24 | #include <linux/jhash.h> |
| 25 | #include <linux/slab.h> |
| 26 | |
| 27 | #include <wrapper/list.h> |
| 28 | #include <lttng-filter.h> |
| 29 | |
| 30 | #define MERGE_POINT_TABLE_BITS 7 |
| 31 | #define MERGE_POINT_TABLE_SIZE (1U << MERGE_POINT_TABLE_BITS) |
| 32 | |
| 33 | /* merge point table node */ |
| 34 | struct mp_node { |
| 35 | struct hlist_node node; |
| 36 | |
| 37 | /* Context at merge point */ |
| 38 | struct vstack stack; |
| 39 | unsigned long target_pc; |
| 40 | }; |
| 41 | |
| 42 | struct mp_table { |
| 43 | struct hlist_head mp_head[MERGE_POINT_TABLE_SIZE]; |
| 44 | }; |
| 45 | |
| 46 | static |
| 47 | int lttng_hash_match(struct mp_node *mp_node, unsigned long key_pc) |
| 48 | { |
| 49 | if (mp_node->target_pc == key_pc) |
| 50 | return 1; |
| 51 | else |
| 52 | return 0; |
| 53 | } |
| 54 | |
| 55 | static |
| 56 | int merge_points_compare(const struct vstack *stacka, |
| 57 | const struct vstack *stackb) |
| 58 | { |
| 59 | int i, len; |
| 60 | |
| 61 | if (stacka->top != stackb->top) |
| 62 | return 1; |
| 63 | len = stacka->top + 1; |
| 64 | WARN_ON_ONCE(len < 0); |
| 65 | for (i = 0; i < len; i++) { |
| 66 | if (stacka->e[i].type != stackb->e[i].type) |
| 67 | return 1; |
| 68 | } |
| 69 | return 0; |
| 70 | } |
| 71 | |
| 72 | static |
| 73 | int merge_point_add_check(struct mp_table *mp_table, unsigned long target_pc, |
| 74 | const struct vstack *stack) |
| 75 | { |
| 76 | struct mp_node *mp_node; |
| 77 | unsigned long hash = jhash_1word(target_pc, 0); |
| 78 | struct hlist_head *head; |
| 79 | struct mp_node *lookup_node; |
| 80 | int found = 0; |
| 81 | |
| 82 | dbg_printk("Filter: adding merge point at offset %lu, hash %lu\n", |
| 83 | target_pc, hash); |
| 84 | mp_node = kzalloc(sizeof(struct mp_node), GFP_KERNEL); |
| 85 | if (!mp_node) |
| 86 | return -ENOMEM; |
| 87 | mp_node->target_pc = target_pc; |
| 88 | memcpy(&mp_node->stack, stack, sizeof(mp_node->stack)); |
| 89 | |
| 90 | head = &mp_table->mp_head[hash & (MERGE_POINT_TABLE_SIZE - 1)]; |
| 91 | lttng_hlist_for_each_entry(lookup_node, head, node) { |
| 92 | if (lttng_hash_match(lookup_node, target_pc)) { |
| 93 | found = 1; |
| 94 | break; |
| 95 | } |
| 96 | } |
| 97 | if (found) { |
| 98 | /* Key already present */ |
| 99 | dbg_printk("Filter: compare merge points for offset %lu, hash %lu\n", |
| 100 | target_pc, hash); |
| 101 | kfree(mp_node); |
| 102 | if (merge_points_compare(stack, &lookup_node->stack)) { |
| 103 | printk(KERN_WARNING "Merge points differ for offset %lu\n", |
| 104 | target_pc); |
| 105 | return -EINVAL; |
| 106 | } |
| 107 | } else { |
| 108 | hlist_add_head(&mp_node->node, head); |
| 109 | } |
| 110 | return 0; |
| 111 | } |
| 112 | |
| 113 | /* |
| 114 | * Binary comparators use top of stack and top of stack -1. |
| 115 | */ |
| 116 | static |
| 117 | int bin_op_compare_check(struct vstack *stack, const char *str) |
| 118 | { |
| 119 | if (unlikely(!vstack_ax(stack) || !vstack_bx(stack))) |
| 120 | goto error_unknown; |
| 121 | |
| 122 | switch (vstack_ax(stack)->type) { |
| 123 | default: |
| 124 | case REG_DOUBLE: |
| 125 | goto error_unknown; |
| 126 | |
| 127 | case REG_STRING: |
| 128 | switch (vstack_bx(stack)->type) { |
| 129 | default: |
| 130 | case REG_DOUBLE: |
| 131 | goto error_unknown; |
| 132 | |
| 133 | case REG_STRING: |
| 134 | break; |
| 135 | case REG_S64: |
| 136 | goto error_mismatch; |
| 137 | } |
| 138 | break; |
| 139 | case REG_S64: |
| 140 | switch (vstack_bx(stack)->type) { |
| 141 | default: |
| 142 | case REG_DOUBLE: |
| 143 | goto error_unknown; |
| 144 | |
| 145 | case REG_STRING: |
| 146 | goto error_mismatch; |
| 147 | |
| 148 | case REG_S64: |
| 149 | break; |
| 150 | } |
| 151 | break; |
| 152 | } |
| 153 | return 0; |
| 154 | |
| 155 | error_unknown: |
| 156 | return -EINVAL; |
| 157 | |
| 158 | error_mismatch: |
| 159 | printk(KERN_WARNING "type mismatch for '%s' binary operator\n", str); |
| 160 | return -EINVAL; |
| 161 | } |
| 162 | |
| 163 | /* |
| 164 | * Validate bytecode range overflow within the validation pass. |
| 165 | * Called for each instruction encountered. |
| 166 | */ |
| 167 | static |
| 168 | int bytecode_validate_overflow(struct bytecode_runtime *bytecode, |
| 169 | char *start_pc, char *pc) |
| 170 | { |
| 171 | int ret = 0; |
| 172 | |
| 173 | switch (*(filter_opcode_t *) pc) { |
| 174 | case FILTER_OP_UNKNOWN: |
| 175 | default: |
| 176 | { |
| 177 | printk(KERN_WARNING "unknown bytecode op %u\n", |
| 178 | (unsigned int) *(filter_opcode_t *) pc); |
| 179 | ret = -EINVAL; |
| 180 | break; |
| 181 | } |
| 182 | |
| 183 | case FILTER_OP_RETURN: |
| 184 | { |
| 185 | if (unlikely(pc + sizeof(struct return_op) |
| 186 | > start_pc + bytecode->len)) { |
| 187 | ret = -ERANGE; |
| 188 | } |
| 189 | break; |
| 190 | } |
| 191 | |
| 192 | /* binary */ |
| 193 | case FILTER_OP_MUL: |
| 194 | case FILTER_OP_DIV: |
| 195 | case FILTER_OP_MOD: |
| 196 | case FILTER_OP_PLUS: |
| 197 | case FILTER_OP_MINUS: |
| 198 | case FILTER_OP_RSHIFT: |
| 199 | case FILTER_OP_LSHIFT: |
| 200 | case FILTER_OP_BIN_AND: |
| 201 | case FILTER_OP_BIN_OR: |
| 202 | case FILTER_OP_BIN_XOR: |
| 203 | case FILTER_OP_EQ_DOUBLE: |
| 204 | case FILTER_OP_NE_DOUBLE: |
| 205 | case FILTER_OP_GT_DOUBLE: |
| 206 | case FILTER_OP_LT_DOUBLE: |
| 207 | case FILTER_OP_GE_DOUBLE: |
| 208 | case FILTER_OP_LE_DOUBLE: |
| 209 | /* Floating point */ |
| 210 | case FILTER_OP_EQ_DOUBLE_S64: |
| 211 | case FILTER_OP_NE_DOUBLE_S64: |
| 212 | case FILTER_OP_GT_DOUBLE_S64: |
| 213 | case FILTER_OP_LT_DOUBLE_S64: |
| 214 | case FILTER_OP_GE_DOUBLE_S64: |
| 215 | case FILTER_OP_LE_DOUBLE_S64: |
| 216 | case FILTER_OP_EQ_S64_DOUBLE: |
| 217 | case FILTER_OP_NE_S64_DOUBLE: |
| 218 | case FILTER_OP_GT_S64_DOUBLE: |
| 219 | case FILTER_OP_LT_S64_DOUBLE: |
| 220 | case FILTER_OP_GE_S64_DOUBLE: |
| 221 | case FILTER_OP_LE_S64_DOUBLE: |
| 222 | case FILTER_OP_LOAD_FIELD_REF_DOUBLE: |
| 223 | case FILTER_OP_GET_CONTEXT_REF_DOUBLE: |
| 224 | case FILTER_OP_LOAD_DOUBLE: |
| 225 | case FILTER_OP_CAST_DOUBLE_TO_S64: |
| 226 | case FILTER_OP_UNARY_PLUS_DOUBLE: |
| 227 | case FILTER_OP_UNARY_MINUS_DOUBLE: |
| 228 | case FILTER_OP_UNARY_NOT_DOUBLE: |
| 229 | { |
| 230 | printk(KERN_WARNING "unsupported bytecode op %u\n", |
| 231 | (unsigned int) *(filter_opcode_t *) pc); |
| 232 | ret = -EINVAL; |
| 233 | break; |
| 234 | } |
| 235 | |
| 236 | case FILTER_OP_EQ: |
| 237 | case FILTER_OP_NE: |
| 238 | case FILTER_OP_GT: |
| 239 | case FILTER_OP_LT: |
| 240 | case FILTER_OP_GE: |
| 241 | case FILTER_OP_LE: |
| 242 | case FILTER_OP_EQ_STRING: |
| 243 | case FILTER_OP_NE_STRING: |
| 244 | case FILTER_OP_GT_STRING: |
| 245 | case FILTER_OP_LT_STRING: |
| 246 | case FILTER_OP_GE_STRING: |
| 247 | case FILTER_OP_LE_STRING: |
| 248 | case FILTER_OP_EQ_S64: |
| 249 | case FILTER_OP_NE_S64: |
| 250 | case FILTER_OP_GT_S64: |
| 251 | case FILTER_OP_LT_S64: |
| 252 | case FILTER_OP_GE_S64: |
| 253 | case FILTER_OP_LE_S64: |
| 254 | { |
| 255 | if (unlikely(pc + sizeof(struct binary_op) |
| 256 | > start_pc + bytecode->len)) { |
| 257 | ret = -ERANGE; |
| 258 | } |
| 259 | break; |
| 260 | } |
| 261 | |
| 262 | /* unary */ |
| 263 | case FILTER_OP_UNARY_PLUS: |
| 264 | case FILTER_OP_UNARY_MINUS: |
| 265 | case FILTER_OP_UNARY_NOT: |
| 266 | case FILTER_OP_UNARY_PLUS_S64: |
| 267 | case FILTER_OP_UNARY_MINUS_S64: |
| 268 | case FILTER_OP_UNARY_NOT_S64: |
| 269 | { |
| 270 | if (unlikely(pc + sizeof(struct unary_op) |
| 271 | > start_pc + bytecode->len)) { |
| 272 | ret = -ERANGE; |
| 273 | } |
| 274 | break; |
| 275 | } |
| 276 | |
| 277 | /* logical */ |
| 278 | case FILTER_OP_AND: |
| 279 | case FILTER_OP_OR: |
| 280 | { |
| 281 | if (unlikely(pc + sizeof(struct logical_op) |
| 282 | > start_pc + bytecode->len)) { |
| 283 | ret = -ERANGE; |
| 284 | } |
| 285 | break; |
| 286 | } |
| 287 | |
| 288 | /* load field ref */ |
| 289 | case FILTER_OP_LOAD_FIELD_REF: |
| 290 | { |
| 291 | printk(KERN_WARNING "Unknown field ref type\n"); |
| 292 | ret = -EINVAL; |
| 293 | break; |
| 294 | } |
| 295 | /* get context ref */ |
| 296 | case FILTER_OP_GET_CONTEXT_REF: |
| 297 | { |
| 298 | printk(KERN_WARNING "Unknown field ref type\n"); |
| 299 | ret = -EINVAL; |
| 300 | break; |
| 301 | } |
| 302 | case FILTER_OP_LOAD_FIELD_REF_STRING: |
| 303 | case FILTER_OP_LOAD_FIELD_REF_SEQUENCE: |
| 304 | case FILTER_OP_LOAD_FIELD_REF_USER_STRING: |
| 305 | case FILTER_OP_LOAD_FIELD_REF_USER_SEQUENCE: |
| 306 | case FILTER_OP_LOAD_FIELD_REF_S64: |
| 307 | case FILTER_OP_GET_CONTEXT_REF_STRING: |
| 308 | case FILTER_OP_GET_CONTEXT_REF_S64: |
| 309 | { |
| 310 | if (unlikely(pc + sizeof(struct load_op) + sizeof(struct field_ref) |
| 311 | > start_pc + bytecode->len)) { |
| 312 | ret = -ERANGE; |
| 313 | } |
| 314 | break; |
| 315 | } |
| 316 | |
| 317 | /* load from immediate operand */ |
| 318 | case FILTER_OP_LOAD_STRING: |
| 319 | { |
| 320 | struct load_op *insn = (struct load_op *) pc; |
| 321 | uint32_t str_len, maxlen; |
| 322 | |
| 323 | if (unlikely(pc + sizeof(struct load_op) |
| 324 | > start_pc + bytecode->len)) { |
| 325 | ret = -ERANGE; |
| 326 | break; |
| 327 | } |
| 328 | |
| 329 | maxlen = start_pc + bytecode->len - pc - sizeof(struct load_op); |
| 330 | str_len = strnlen(insn->data, maxlen); |
| 331 | if (unlikely(str_len >= maxlen)) { |
| 332 | /* Final '\0' not found within range */ |
| 333 | ret = -ERANGE; |
| 334 | } |
| 335 | break; |
| 336 | } |
| 337 | |
| 338 | case FILTER_OP_LOAD_S64: |
| 339 | { |
| 340 | if (unlikely(pc + sizeof(struct load_op) + sizeof(struct literal_numeric) |
| 341 | > start_pc + bytecode->len)) { |
| 342 | ret = -ERANGE; |
| 343 | } |
| 344 | break; |
| 345 | } |
| 346 | |
| 347 | case FILTER_OP_CAST_TO_S64: |
| 348 | case FILTER_OP_CAST_NOP: |
| 349 | { |
| 350 | if (unlikely(pc + sizeof(struct cast_op) |
| 351 | > start_pc + bytecode->len)) { |
| 352 | ret = -ERANGE; |
| 353 | } |
| 354 | break; |
| 355 | } |
| 356 | |
| 357 | } |
| 358 | |
| 359 | return ret; |
| 360 | } |
| 361 | |
| 362 | static |
| 363 | unsigned long delete_all_nodes(struct mp_table *mp_table) |
| 364 | { |
| 365 | struct mp_node *mp_node; |
| 366 | struct hlist_node *tmp; |
| 367 | unsigned long nr_nodes = 0; |
| 368 | int i; |
| 369 | |
| 370 | for (i = 0; i < MERGE_POINT_TABLE_SIZE; i++) { |
| 371 | struct hlist_head *head; |
| 372 | |
| 373 | head = &mp_table->mp_head[i]; |
| 374 | lttng_hlist_for_each_entry_safe(mp_node, tmp, head, node) { |
| 375 | kfree(mp_node); |
| 376 | nr_nodes++; |
| 377 | } |
| 378 | } |
| 379 | return nr_nodes; |
| 380 | } |
| 381 | |
| 382 | /* |
| 383 | * Return value: |
| 384 | * 0: success |
| 385 | * <0: error |
| 386 | */ |
| 387 | static |
| 388 | int validate_instruction_context(struct bytecode_runtime *bytecode, |
| 389 | struct vstack *stack, |
| 390 | char *start_pc, |
| 391 | char *pc) |
| 392 | { |
| 393 | int ret = 0; |
| 394 | |
| 395 | switch (*(filter_opcode_t *) pc) { |
| 396 | case FILTER_OP_UNKNOWN: |
| 397 | default: |
| 398 | { |
| 399 | printk(KERN_WARNING "unknown bytecode op %u\n", |
| 400 | (unsigned int) *(filter_opcode_t *) pc); |
| 401 | ret = -EINVAL; |
| 402 | goto end; |
| 403 | } |
| 404 | |
| 405 | case FILTER_OP_RETURN: |
| 406 | { |
| 407 | goto end; |
| 408 | } |
| 409 | |
| 410 | /* binary */ |
| 411 | case FILTER_OP_MUL: |
| 412 | case FILTER_OP_DIV: |
| 413 | case FILTER_OP_MOD: |
| 414 | case FILTER_OP_PLUS: |
| 415 | case FILTER_OP_MINUS: |
| 416 | case FILTER_OP_RSHIFT: |
| 417 | case FILTER_OP_LSHIFT: |
| 418 | case FILTER_OP_BIN_AND: |
| 419 | case FILTER_OP_BIN_OR: |
| 420 | case FILTER_OP_BIN_XOR: |
| 421 | /* Floating point */ |
| 422 | case FILTER_OP_EQ_DOUBLE: |
| 423 | case FILTER_OP_NE_DOUBLE: |
| 424 | case FILTER_OP_GT_DOUBLE: |
| 425 | case FILTER_OP_LT_DOUBLE: |
| 426 | case FILTER_OP_GE_DOUBLE: |
| 427 | case FILTER_OP_LE_DOUBLE: |
| 428 | case FILTER_OP_EQ_DOUBLE_S64: |
| 429 | case FILTER_OP_NE_DOUBLE_S64: |
| 430 | case FILTER_OP_GT_DOUBLE_S64: |
| 431 | case FILTER_OP_LT_DOUBLE_S64: |
| 432 | case FILTER_OP_GE_DOUBLE_S64: |
| 433 | case FILTER_OP_LE_DOUBLE_S64: |
| 434 | case FILTER_OP_EQ_S64_DOUBLE: |
| 435 | case FILTER_OP_NE_S64_DOUBLE: |
| 436 | case FILTER_OP_GT_S64_DOUBLE: |
| 437 | case FILTER_OP_LT_S64_DOUBLE: |
| 438 | case FILTER_OP_GE_S64_DOUBLE: |
| 439 | case FILTER_OP_LE_S64_DOUBLE: |
| 440 | case FILTER_OP_UNARY_PLUS_DOUBLE: |
| 441 | case FILTER_OP_UNARY_MINUS_DOUBLE: |
| 442 | case FILTER_OP_UNARY_NOT_DOUBLE: |
| 443 | case FILTER_OP_LOAD_FIELD_REF_DOUBLE: |
| 444 | case FILTER_OP_LOAD_DOUBLE: |
| 445 | case FILTER_OP_CAST_DOUBLE_TO_S64: |
| 446 | case FILTER_OP_GET_CONTEXT_REF_DOUBLE: |
| 447 | { |
| 448 | printk(KERN_WARNING "unsupported bytecode op %u\n", |
| 449 | (unsigned int) *(filter_opcode_t *) pc); |
| 450 | ret = -EINVAL; |
| 451 | goto end; |
| 452 | } |
| 453 | |
| 454 | case FILTER_OP_EQ: |
| 455 | { |
| 456 | ret = bin_op_compare_check(stack, "=="); |
| 457 | if (ret) |
| 458 | goto end; |
| 459 | break; |
| 460 | } |
| 461 | case FILTER_OP_NE: |
| 462 | { |
| 463 | ret = bin_op_compare_check(stack, "!="); |
| 464 | if (ret) |
| 465 | goto end; |
| 466 | break; |
| 467 | } |
| 468 | case FILTER_OP_GT: |
| 469 | { |
| 470 | ret = bin_op_compare_check(stack, ">"); |
| 471 | if (ret) |
| 472 | goto end; |
| 473 | break; |
| 474 | } |
| 475 | case FILTER_OP_LT: |
| 476 | { |
| 477 | ret = bin_op_compare_check(stack, "<"); |
| 478 | if (ret) |
| 479 | goto end; |
| 480 | break; |
| 481 | } |
| 482 | case FILTER_OP_GE: |
| 483 | { |
| 484 | ret = bin_op_compare_check(stack, ">="); |
| 485 | if (ret) |
| 486 | goto end; |
| 487 | break; |
| 488 | } |
| 489 | case FILTER_OP_LE: |
| 490 | { |
| 491 | ret = bin_op_compare_check(stack, "<="); |
| 492 | if (ret) |
| 493 | goto end; |
| 494 | break; |
| 495 | } |
| 496 | |
| 497 | case FILTER_OP_EQ_STRING: |
| 498 | case FILTER_OP_NE_STRING: |
| 499 | case FILTER_OP_GT_STRING: |
| 500 | case FILTER_OP_LT_STRING: |
| 501 | case FILTER_OP_GE_STRING: |
| 502 | case FILTER_OP_LE_STRING: |
| 503 | { |
| 504 | if (!vstack_ax(stack) || !vstack_bx(stack)) { |
| 505 | printk(KERN_WARNING "Empty stack\n"); |
| 506 | ret = -EINVAL; |
| 507 | goto end; |
| 508 | } |
| 509 | if (vstack_ax(stack)->type != REG_STRING |
| 510 | || vstack_bx(stack)->type != REG_STRING) { |
| 511 | printk(KERN_WARNING "Unexpected register type for string comparator\n"); |
| 512 | ret = -EINVAL; |
| 513 | goto end; |
| 514 | } |
| 515 | break; |
| 516 | } |
| 517 | |
| 518 | case FILTER_OP_EQ_S64: |
| 519 | case FILTER_OP_NE_S64: |
| 520 | case FILTER_OP_GT_S64: |
| 521 | case FILTER_OP_LT_S64: |
| 522 | case FILTER_OP_GE_S64: |
| 523 | case FILTER_OP_LE_S64: |
| 524 | { |
| 525 | if (!vstack_ax(stack) || !vstack_bx(stack)) { |
| 526 | printk(KERN_WARNING "Empty stack\n"); |
| 527 | ret = -EINVAL; |
| 528 | goto end; |
| 529 | } |
| 530 | if (vstack_ax(stack)->type != REG_S64 |
| 531 | || vstack_bx(stack)->type != REG_S64) { |
| 532 | printk(KERN_WARNING "Unexpected register type for s64 comparator\n"); |
| 533 | ret = -EINVAL; |
| 534 | goto end; |
| 535 | } |
| 536 | break; |
| 537 | } |
| 538 | |
| 539 | /* unary */ |
| 540 | case FILTER_OP_UNARY_PLUS: |
| 541 | case FILTER_OP_UNARY_MINUS: |
| 542 | case FILTER_OP_UNARY_NOT: |
| 543 | { |
| 544 | if (!vstack_ax(stack)) { |
| 545 | printk(KERN_WARNING "Empty stack\n"); |
| 546 | ret = -EINVAL; |
| 547 | goto end; |
| 548 | } |
| 549 | switch (vstack_ax(stack)->type) { |
| 550 | default: |
| 551 | case REG_DOUBLE: |
| 552 | printk(KERN_WARNING "unknown register type\n"); |
| 553 | ret = -EINVAL; |
| 554 | goto end; |
| 555 | |
| 556 | case REG_STRING: |
| 557 | printk(KERN_WARNING "Unary op can only be applied to numeric or floating point registers\n"); |
| 558 | ret = -EINVAL; |
| 559 | goto end; |
| 560 | case REG_S64: |
| 561 | break; |
| 562 | } |
| 563 | break; |
| 564 | } |
| 565 | |
| 566 | case FILTER_OP_UNARY_PLUS_S64: |
| 567 | case FILTER_OP_UNARY_MINUS_S64: |
| 568 | case FILTER_OP_UNARY_NOT_S64: |
| 569 | { |
| 570 | if (!vstack_ax(stack)) { |
| 571 | printk(KERN_WARNING "Empty stack\n"); |
| 572 | ret = -EINVAL; |
| 573 | goto end; |
| 574 | } |
| 575 | if (vstack_ax(stack)->type != REG_S64) { |
| 576 | printk(KERN_WARNING "Invalid register type\n"); |
| 577 | ret = -EINVAL; |
| 578 | goto end; |
| 579 | } |
| 580 | break; |
| 581 | } |
| 582 | |
| 583 | /* logical */ |
| 584 | case FILTER_OP_AND: |
| 585 | case FILTER_OP_OR: |
| 586 | { |
| 587 | struct logical_op *insn = (struct logical_op *) pc; |
| 588 | |
| 589 | if (!vstack_ax(stack)) { |
| 590 | printk(KERN_WARNING "Empty stack\n"); |
| 591 | ret = -EINVAL; |
| 592 | goto end; |
| 593 | } |
| 594 | if (vstack_ax(stack)->type != REG_S64) { |
| 595 | printk(KERN_WARNING "Logical comparator expects S64 register\n"); |
| 596 | ret = -EINVAL; |
| 597 | goto end; |
| 598 | } |
| 599 | |
| 600 | dbg_printk("Validate jumping to bytecode offset %u\n", |
| 601 | (unsigned int) insn->skip_offset); |
| 602 | if (unlikely(start_pc + insn->skip_offset <= pc)) { |
| 603 | printk(KERN_WARNING "Loops are not allowed in bytecode\n"); |
| 604 | ret = -EINVAL; |
| 605 | goto end; |
| 606 | } |
| 607 | break; |
| 608 | } |
| 609 | |
| 610 | /* load field ref */ |
| 611 | case FILTER_OP_LOAD_FIELD_REF: |
| 612 | { |
| 613 | printk(KERN_WARNING "Unknown field ref type\n"); |
| 614 | ret = -EINVAL; |
| 615 | goto end; |
| 616 | } |
| 617 | case FILTER_OP_LOAD_FIELD_REF_STRING: |
| 618 | case FILTER_OP_LOAD_FIELD_REF_SEQUENCE: |
| 619 | case FILTER_OP_LOAD_FIELD_REF_USER_STRING: |
| 620 | case FILTER_OP_LOAD_FIELD_REF_USER_SEQUENCE: |
| 621 | { |
| 622 | struct load_op *insn = (struct load_op *) pc; |
| 623 | struct field_ref *ref = (struct field_ref *) insn->data; |
| 624 | |
| 625 | dbg_printk("Validate load field ref offset %u type string\n", |
| 626 | ref->offset); |
| 627 | break; |
| 628 | } |
| 629 | case FILTER_OP_LOAD_FIELD_REF_S64: |
| 630 | { |
| 631 | struct load_op *insn = (struct load_op *) pc; |
| 632 | struct field_ref *ref = (struct field_ref *) insn->data; |
| 633 | |
| 634 | dbg_printk("Validate load field ref offset %u type s64\n", |
| 635 | ref->offset); |
| 636 | break; |
| 637 | } |
| 638 | |
| 639 | /* load from immediate operand */ |
| 640 | case FILTER_OP_LOAD_STRING: |
| 641 | { |
| 642 | break; |
| 643 | } |
| 644 | |
| 645 | case FILTER_OP_LOAD_S64: |
| 646 | { |
| 647 | break; |
| 648 | } |
| 649 | |
| 650 | case FILTER_OP_CAST_TO_S64: |
| 651 | { |
| 652 | struct cast_op *insn = (struct cast_op *) pc; |
| 653 | |
| 654 | if (!vstack_ax(stack)) { |
| 655 | printk(KERN_WARNING "Empty stack\n"); |
| 656 | ret = -EINVAL; |
| 657 | goto end; |
| 658 | } |
| 659 | switch (vstack_ax(stack)->type) { |
| 660 | default: |
| 661 | case REG_DOUBLE: |
| 662 | printk(KERN_WARNING "unknown register type\n"); |
| 663 | ret = -EINVAL; |
| 664 | goto end; |
| 665 | |
| 666 | case REG_STRING: |
| 667 | printk(KERN_WARNING "Cast op can only be applied to numeric or floating point registers\n"); |
| 668 | ret = -EINVAL; |
| 669 | goto end; |
| 670 | case REG_S64: |
| 671 | break; |
| 672 | } |
| 673 | if (insn->op == FILTER_OP_CAST_DOUBLE_TO_S64) { |
| 674 | if (vstack_ax(stack)->type != REG_DOUBLE) { |
| 675 | printk(KERN_WARNING "Cast expects double\n"); |
| 676 | ret = -EINVAL; |
| 677 | goto end; |
| 678 | } |
| 679 | } |
| 680 | break; |
| 681 | } |
| 682 | case FILTER_OP_CAST_NOP: |
| 683 | { |
| 684 | break; |
| 685 | } |
| 686 | |
| 687 | /* get context ref */ |
| 688 | case FILTER_OP_GET_CONTEXT_REF: |
| 689 | { |
| 690 | printk(KERN_WARNING "Unknown get context ref type\n"); |
| 691 | ret = -EINVAL; |
| 692 | goto end; |
| 693 | } |
| 694 | case FILTER_OP_GET_CONTEXT_REF_STRING: |
| 695 | { |
| 696 | struct load_op *insn = (struct load_op *) pc; |
| 697 | struct field_ref *ref = (struct field_ref *) insn->data; |
| 698 | |
| 699 | dbg_printk("Validate get context ref offset %u type string\n", |
| 700 | ref->offset); |
| 701 | break; |
| 702 | } |
| 703 | case FILTER_OP_GET_CONTEXT_REF_S64: |
| 704 | { |
| 705 | struct load_op *insn = (struct load_op *) pc; |
| 706 | struct field_ref *ref = (struct field_ref *) insn->data; |
| 707 | |
| 708 | dbg_printk("Validate get context ref offset %u type s64\n", |
| 709 | ref->offset); |
| 710 | break; |
| 711 | } |
| 712 | |
| 713 | } |
| 714 | end: |
| 715 | return ret; |
| 716 | } |
| 717 | |
| 718 | /* |
| 719 | * Return value: |
| 720 | * 0: success |
| 721 | * <0: error |
| 722 | */ |
| 723 | static |
| 724 | int validate_instruction_all_contexts(struct bytecode_runtime *bytecode, |
| 725 | struct mp_table *mp_table, |
| 726 | struct vstack *stack, |
| 727 | char *start_pc, |
| 728 | char *pc) |
| 729 | { |
| 730 | int ret, found = 0; |
| 731 | unsigned long target_pc = pc - start_pc; |
| 732 | unsigned long hash; |
| 733 | struct hlist_head *head; |
| 734 | struct mp_node *mp_node; |
| 735 | |
| 736 | /* Validate the context resulting from the previous instruction */ |
| 737 | ret = validate_instruction_context(bytecode, stack, start_pc, pc); |
| 738 | if (ret) |
| 739 | return ret; |
| 740 | |
| 741 | /* Validate merge points */ |
| 742 | hash = jhash_1word(target_pc, 0); |
| 743 | head = &mp_table->mp_head[hash & (MERGE_POINT_TABLE_SIZE - 1)]; |
| 744 | lttng_hlist_for_each_entry(mp_node, head, node) { |
| 745 | if (lttng_hash_match(mp_node, target_pc)) { |
| 746 | found = 1; |
| 747 | break; |
| 748 | } |
| 749 | } |
| 750 | if (found) { |
| 751 | dbg_printk("Filter: validate merge point at offset %lu\n", |
| 752 | target_pc); |
| 753 | if (merge_points_compare(stack, &mp_node->stack)) { |
| 754 | printk(KERN_WARNING "Merge points differ for offset %lu\n", |
| 755 | target_pc); |
| 756 | return -EINVAL; |
| 757 | } |
| 758 | /* Once validated, we can remove the merge point */ |
| 759 | dbg_printk("Filter: remove merge point at offset %lu\n", |
| 760 | target_pc); |
| 761 | hlist_del(&mp_node->node); |
| 762 | } |
| 763 | return 0; |
| 764 | } |
| 765 | |
| 766 | /* |
| 767 | * Return value: |
| 768 | * >0: going to next insn. |
| 769 | * 0: success, stop iteration. |
| 770 | * <0: error |
| 771 | */ |
| 772 | static |
| 773 | int exec_insn(struct bytecode_runtime *bytecode, |
| 774 | struct mp_table *mp_table, |
| 775 | struct vstack *stack, |
| 776 | char **_next_pc, |
| 777 | char *pc) |
| 778 | { |
| 779 | int ret = 1; |
| 780 | char *next_pc = *_next_pc; |
| 781 | |
| 782 | switch (*(filter_opcode_t *) pc) { |
| 783 | case FILTER_OP_UNKNOWN: |
| 784 | default: |
| 785 | { |
| 786 | printk(KERN_WARNING "unknown bytecode op %u\n", |
| 787 | (unsigned int) *(filter_opcode_t *) pc); |
| 788 | ret = -EINVAL; |
| 789 | goto end; |
| 790 | } |
| 791 | |
| 792 | case FILTER_OP_RETURN: |
| 793 | { |
| 794 | if (!vstack_ax(stack)) { |
| 795 | printk(KERN_WARNING "Empty stack\n"); |
| 796 | ret = -EINVAL; |
| 797 | goto end; |
| 798 | } |
| 799 | ret = 0; |
| 800 | goto end; |
| 801 | } |
| 802 | |
| 803 | /* binary */ |
| 804 | case FILTER_OP_MUL: |
| 805 | case FILTER_OP_DIV: |
| 806 | case FILTER_OP_MOD: |
| 807 | case FILTER_OP_PLUS: |
| 808 | case FILTER_OP_MINUS: |
| 809 | case FILTER_OP_RSHIFT: |
| 810 | case FILTER_OP_LSHIFT: |
| 811 | case FILTER_OP_BIN_AND: |
| 812 | case FILTER_OP_BIN_OR: |
| 813 | case FILTER_OP_BIN_XOR: |
| 814 | /* Floating point */ |
| 815 | case FILTER_OP_EQ_DOUBLE: |
| 816 | case FILTER_OP_NE_DOUBLE: |
| 817 | case FILTER_OP_GT_DOUBLE: |
| 818 | case FILTER_OP_LT_DOUBLE: |
| 819 | case FILTER_OP_GE_DOUBLE: |
| 820 | case FILTER_OP_LE_DOUBLE: |
| 821 | case FILTER_OP_EQ_DOUBLE_S64: |
| 822 | case FILTER_OP_NE_DOUBLE_S64: |
| 823 | case FILTER_OP_GT_DOUBLE_S64: |
| 824 | case FILTER_OP_LT_DOUBLE_S64: |
| 825 | case FILTER_OP_GE_DOUBLE_S64: |
| 826 | case FILTER_OP_LE_DOUBLE_S64: |
| 827 | case FILTER_OP_EQ_S64_DOUBLE: |
| 828 | case FILTER_OP_NE_S64_DOUBLE: |
| 829 | case FILTER_OP_GT_S64_DOUBLE: |
| 830 | case FILTER_OP_LT_S64_DOUBLE: |
| 831 | case FILTER_OP_GE_S64_DOUBLE: |
| 832 | case FILTER_OP_LE_S64_DOUBLE: |
| 833 | case FILTER_OP_UNARY_PLUS_DOUBLE: |
| 834 | case FILTER_OP_UNARY_MINUS_DOUBLE: |
| 835 | case FILTER_OP_UNARY_NOT_DOUBLE: |
| 836 | case FILTER_OP_LOAD_FIELD_REF_DOUBLE: |
| 837 | case FILTER_OP_GET_CONTEXT_REF_DOUBLE: |
| 838 | case FILTER_OP_LOAD_DOUBLE: |
| 839 | case FILTER_OP_CAST_DOUBLE_TO_S64: |
| 840 | { |
| 841 | printk(KERN_WARNING "unsupported bytecode op %u\n", |
| 842 | (unsigned int) *(filter_opcode_t *) pc); |
| 843 | ret = -EINVAL; |
| 844 | goto end; |
| 845 | } |
| 846 | |
| 847 | case FILTER_OP_EQ: |
| 848 | case FILTER_OP_NE: |
| 849 | case FILTER_OP_GT: |
| 850 | case FILTER_OP_LT: |
| 851 | case FILTER_OP_GE: |
| 852 | case FILTER_OP_LE: |
| 853 | case FILTER_OP_EQ_STRING: |
| 854 | case FILTER_OP_NE_STRING: |
| 855 | case FILTER_OP_GT_STRING: |
| 856 | case FILTER_OP_LT_STRING: |
| 857 | case FILTER_OP_GE_STRING: |
| 858 | case FILTER_OP_LE_STRING: |
| 859 | case FILTER_OP_EQ_S64: |
| 860 | case FILTER_OP_NE_S64: |
| 861 | case FILTER_OP_GT_S64: |
| 862 | case FILTER_OP_LT_S64: |
| 863 | case FILTER_OP_GE_S64: |
| 864 | case FILTER_OP_LE_S64: |
| 865 | { |
| 866 | /* Pop 2, push 1 */ |
| 867 | if (vstack_pop(stack)) { |
| 868 | ret = -EINVAL; |
| 869 | goto end; |
| 870 | } |
| 871 | if (!vstack_ax(stack)) { |
| 872 | printk(KERN_WARNING "Empty stack\n"); |
| 873 | ret = -EINVAL; |
| 874 | goto end; |
| 875 | } |
| 876 | vstack_ax(stack)->type = REG_S64; |
| 877 | next_pc += sizeof(struct binary_op); |
| 878 | break; |
| 879 | } |
| 880 | |
| 881 | /* unary */ |
| 882 | case FILTER_OP_UNARY_PLUS: |
| 883 | case FILTER_OP_UNARY_MINUS: |
| 884 | case FILTER_OP_UNARY_NOT: |
| 885 | case FILTER_OP_UNARY_PLUS_S64: |
| 886 | case FILTER_OP_UNARY_MINUS_S64: |
| 887 | case FILTER_OP_UNARY_NOT_S64: |
| 888 | { |
| 889 | /* Pop 1, push 1 */ |
| 890 | if (!vstack_ax(stack)) { |
| 891 | printk(KERN_WARNING "Empty stack\n"); |
| 892 | ret = -EINVAL; |
| 893 | goto end; |
| 894 | } |
| 895 | vstack_ax(stack)->type = REG_S64; |
| 896 | next_pc += sizeof(struct unary_op); |
| 897 | break; |
| 898 | } |
| 899 | |
| 900 | /* logical */ |
| 901 | case FILTER_OP_AND: |
| 902 | case FILTER_OP_OR: |
| 903 | { |
| 904 | struct logical_op *insn = (struct logical_op *) pc; |
| 905 | int merge_ret; |
| 906 | |
| 907 | /* Add merge point to table */ |
| 908 | merge_ret = merge_point_add_check(mp_table, |
| 909 | insn->skip_offset, stack); |
| 910 | if (merge_ret) { |
| 911 | ret = merge_ret; |
| 912 | goto end; |
| 913 | } |
| 914 | /* Continue to next instruction */ |
| 915 | /* Pop 1 when jump not taken */ |
| 916 | if (vstack_pop(stack)) { |
| 917 | ret = -EINVAL; |
| 918 | goto end; |
| 919 | } |
| 920 | next_pc += sizeof(struct logical_op); |
| 921 | break; |
| 922 | } |
| 923 | |
| 924 | /* load field ref */ |
| 925 | case FILTER_OP_LOAD_FIELD_REF: |
| 926 | { |
| 927 | printk(KERN_WARNING "Unknown field ref type\n"); |
| 928 | ret = -EINVAL; |
| 929 | goto end; |
| 930 | } |
| 931 | /* get context ref */ |
| 932 | case FILTER_OP_GET_CONTEXT_REF: |
| 933 | { |
| 934 | printk(KERN_WARNING "Unknown get context ref type\n"); |
| 935 | ret = -EINVAL; |
| 936 | goto end; |
| 937 | } |
| 938 | case FILTER_OP_LOAD_FIELD_REF_STRING: |
| 939 | case FILTER_OP_LOAD_FIELD_REF_SEQUENCE: |
| 940 | case FILTER_OP_GET_CONTEXT_REF_STRING: |
| 941 | case FILTER_OP_LOAD_FIELD_REF_USER_STRING: |
| 942 | case FILTER_OP_LOAD_FIELD_REF_USER_SEQUENCE: |
| 943 | { |
| 944 | if (vstack_push(stack)) { |
| 945 | ret = -EINVAL; |
| 946 | goto end; |
| 947 | } |
| 948 | vstack_ax(stack)->type = REG_STRING; |
| 949 | next_pc += sizeof(struct load_op) + sizeof(struct field_ref); |
| 950 | break; |
| 951 | } |
| 952 | case FILTER_OP_LOAD_FIELD_REF_S64: |
| 953 | case FILTER_OP_GET_CONTEXT_REF_S64: |
| 954 | { |
| 955 | if (vstack_push(stack)) { |
| 956 | ret = -EINVAL; |
| 957 | goto end; |
| 958 | } |
| 959 | vstack_ax(stack)->type = REG_S64; |
| 960 | next_pc += sizeof(struct load_op) + sizeof(struct field_ref); |
| 961 | break; |
| 962 | } |
| 963 | |
| 964 | /* load from immediate operand */ |
| 965 | case FILTER_OP_LOAD_STRING: |
| 966 | { |
| 967 | struct load_op *insn = (struct load_op *) pc; |
| 968 | |
| 969 | if (vstack_push(stack)) { |
| 970 | ret = -EINVAL; |
| 971 | goto end; |
| 972 | } |
| 973 | vstack_ax(stack)->type = REG_STRING; |
| 974 | next_pc += sizeof(struct load_op) + strlen(insn->data) + 1; |
| 975 | break; |
| 976 | } |
| 977 | |
| 978 | case FILTER_OP_LOAD_S64: |
| 979 | { |
| 980 | if (vstack_push(stack)) { |
| 981 | ret = -EINVAL; |
| 982 | goto end; |
| 983 | } |
| 984 | vstack_ax(stack)->type = REG_S64; |
| 985 | next_pc += sizeof(struct load_op) |
| 986 | + sizeof(struct literal_numeric); |
| 987 | break; |
| 988 | } |
| 989 | |
| 990 | case FILTER_OP_CAST_TO_S64: |
| 991 | { |
| 992 | /* Pop 1, push 1 */ |
| 993 | if (!vstack_ax(stack)) { |
| 994 | printk(KERN_WARNING "Empty stack\n"); |
| 995 | ret = -EINVAL; |
| 996 | goto end; |
| 997 | } |
| 998 | vstack_ax(stack)->type = REG_S64; |
| 999 | next_pc += sizeof(struct cast_op); |
| 1000 | break; |
| 1001 | } |
| 1002 | case FILTER_OP_CAST_NOP: |
| 1003 | { |
| 1004 | next_pc += sizeof(struct cast_op); |
| 1005 | break; |
| 1006 | } |
| 1007 | |
| 1008 | } |
| 1009 | end: |
| 1010 | *_next_pc = next_pc; |
| 1011 | return ret; |
| 1012 | } |
| 1013 | |
| 1014 | /* |
| 1015 | * Never called concurrently (hash seed is shared). |
| 1016 | */ |
| 1017 | int lttng_filter_validate_bytecode(struct bytecode_runtime *bytecode) |
| 1018 | { |
| 1019 | struct mp_table *mp_table; |
| 1020 | char *pc, *next_pc, *start_pc; |
| 1021 | int ret = -EINVAL; |
| 1022 | struct vstack stack; |
| 1023 | |
| 1024 | vstack_init(&stack); |
| 1025 | |
| 1026 | mp_table = kzalloc(sizeof(*mp_table), GFP_KERNEL); |
| 1027 | if (!mp_table) { |
| 1028 | printk(KERN_WARNING "Error allocating hash table for bytecode validation\n"); |
| 1029 | return -ENOMEM; |
| 1030 | } |
| 1031 | start_pc = &bytecode->data[0]; |
| 1032 | for (pc = next_pc = start_pc; pc - start_pc < bytecode->len; |
| 1033 | pc = next_pc) { |
| 1034 | ret = bytecode_validate_overflow(bytecode, start_pc, pc); |
| 1035 | if (ret != 0) { |
| 1036 | if (ret == -ERANGE) |
| 1037 | printk(KERN_WARNING "filter bytecode overflow\n"); |
| 1038 | goto end; |
| 1039 | } |
| 1040 | dbg_printk("Validating op %s (%u)\n", |
| 1041 | lttng_filter_print_op((unsigned int) *(filter_opcode_t *) pc), |
| 1042 | (unsigned int) *(filter_opcode_t *) pc); |
| 1043 | |
| 1044 | /* |
| 1045 | * For each instruction, validate the current context |
| 1046 | * (traversal of entire execution flow), and validate |
| 1047 | * all merge points targeting this instruction. |
| 1048 | */ |
| 1049 | ret = validate_instruction_all_contexts(bytecode, mp_table, |
| 1050 | &stack, start_pc, pc); |
| 1051 | if (ret) |
| 1052 | goto end; |
| 1053 | ret = exec_insn(bytecode, mp_table, &stack, &next_pc, pc); |
| 1054 | if (ret <= 0) |
| 1055 | goto end; |
| 1056 | } |
| 1057 | end: |
| 1058 | if (delete_all_nodes(mp_table)) { |
| 1059 | if (!ret) { |
| 1060 | printk(KERN_WARNING "Unexpected merge points\n"); |
| 1061 | ret = -EINVAL; |
| 1062 | } |
| 1063 | } |
| 1064 | kfree(mp_table); |
| 1065 | return ret; |
| 1066 | } |