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| 1 /* | |
| 2 * Copyright (c) 2012 The Native Client Authors. All rights reserved. | |
| 3 * Use of this source code is governed by a BSD-style license that can be | |
| 4 * found in the LICENSE file. | |
| 5 */ | |
| 6 | |
| 7 /* | |
| 8 * ncvalidate_iter.c | |
| 9 * Validate x86 instructions for Native Client | |
| 10 * | |
| 11 */ | |
| 12 | |
| 13 #include "native_client/src/trusted/validator/x86/ncval_reg_sfi/ncvalidate_iter.
h" | |
| 14 | |
| 15 #include <assert.h> | |
| 16 #include <string.h> | |
| 17 | |
| 18 #include "native_client/src/include/portability_io.h" | |
| 19 #include "native_client/src/shared/platform/nacl_check.h" | |
| 20 #include "native_client/src/shared/platform/nacl_log.h" | |
| 21 #include "native_client/src/trusted/validator/x86/decoder/ncop_exps.h" | |
| 22 #include "native_client/src/trusted/validator/x86/decoder/nc_inst_state_internal
.h" | |
| 23 #include "native_client/src/trusted/validator/x86/halt_trim.h" | |
| 24 #include "native_client/src/trusted/validator/x86/nc_segment.h" | |
| 25 #include "native_client/src/trusted/validator/x86/ncval_reg_sfi/ncvalidate_iter_
internal.h" | |
| 26 #include "native_client/src/trusted/validator/x86/ncval_reg_sfi/ncval_decode_tab
les.h" | |
| 27 #include "native_client/src/trusted/validator/x86/ncval_reg_sfi/nc_illegal.h" | |
| 28 #include "native_client/src/trusted/validator/x86/ncval_reg_sfi/nc_jumps.h" | |
| 29 #include "native_client/src/trusted/validator/x86/ncval_reg_sfi/nc_jumps_detaile
d.h" | |
| 30 #include "native_client/src/trusted/validator/x86/ncval_reg_sfi/nc_memory_protec
t.h" | |
| 31 #ifdef NCVAL_TESTING | |
| 32 #include "native_client/src/trusted/validator/x86/ncval_reg_sfi/nc_postconds.h" | |
| 33 #endif | |
| 34 #include "native_client/src/trusted/validator_x86/ncdis_decode_tables.h" | |
| 35 | |
| 36 /* To turn on debugging of instruction decoding, change value of | |
| 37 * DEBUGGING to 1. | |
| 38 */ | |
| 39 #define DEBUGGING 0 | |
| 40 | |
| 41 #include "native_client/src/shared/utils/debugging.h" | |
| 42 | |
| 43 #include "native_client/src/trusted/validator/x86/decoder/nc_inst_iter_inl.c" | |
| 44 | |
| 45 /* When >= 0, only print that many errors before quiting. When | |
| 46 * < 0, print all errors. | |
| 47 */ | |
| 48 int NACL_FLAGS_max_reported_errors = | |
| 49 #ifdef NCVAL_TESTING | |
| 50 /* Turn off error reporting when generating pre/post conditions. | |
| 51 * Note: conditional code for NCVAL_TESTING will reset the | |
| 52 * quit flag after each instruction. Hence, by using 0, we | |
| 53 * effectively turn off printing of errors as the default. However, | |
| 54 * one can override this on the command line to force errors to | |
| 55 * be printed as well. | |
| 56 */ | |
| 57 0 | |
| 58 #else | |
| 59 100 | |
| 60 #endif | |
| 61 ; | |
| 62 | |
| 63 Bool NACL_FLAGS_validator_trace_instructions = FALSE; | |
| 64 | |
| 65 Bool NACL_FLAGS_validator_trace_inst_internals = FALSE; | |
| 66 | |
| 67 Bool NACL_FLAGS_ncval_annotate = TRUE; | |
| 68 | |
| 69 Bool NACL_FLAGS_unsafe_single_inst_mode = FALSE; | |
| 70 | |
| 71 #ifdef NCVAL_TESTING | |
| 72 Bool NACL_FLAGS_report_conditions_on_all = FALSE; | |
| 73 | |
| 74 void NaClConditionAppend(char* condition, | |
| 75 char** buffer, | |
| 76 size_t* remaining_buffer_size) { | |
| 77 size_t bsize = strlen(condition); | |
| 78 *buffer = condition + bsize; | |
| 79 if (bsize > 0) { | |
| 80 /* Add that we are adding an alternative. */ | |
| 81 SNPRINTF(*buffer, NCVAL_CONDITION_SIZE - bsize, | |
| 82 "&"); | |
| 83 bsize = strlen(condition); | |
| 84 *buffer = condition + bsize; | |
| 85 } | |
| 86 *remaining_buffer_size = NCVAL_CONDITION_SIZE - bsize; | |
| 87 } | |
| 88 #endif | |
| 89 | |
| 90 /* Define the stop instruction. */ | |
| 91 const uint8_t kNaClFullStop = 0xf4; /* x86 HALT opcode */ | |
| 92 | |
| 93 void NaClValidatorFlagsSetTraceVerbose(void) { | |
| 94 NACL_FLAGS_validator_trace_instructions = TRUE; | |
| 95 NACL_FLAGS_validator_trace_inst_internals = TRUE; | |
| 96 } | |
| 97 | |
| 98 int NaClValidatorStateGetMaxReportedErrors(NaClValidatorState *vstate) { | |
| 99 return vstate->quit_after_error_count; | |
| 100 } | |
| 101 | |
| 102 void NaClValidatorStateSetMaxReportedErrors(NaClValidatorState *vstate, | |
| 103 int new_value) { | |
| 104 vstate->quit_after_error_count = new_value; | |
| 105 vstate->quit = NaClValidatorQuit(vstate); | |
| 106 } | |
| 107 | |
| 108 Bool NaClValidatorStateGetTraceInstructions(NaClValidatorState *vstate) { | |
| 109 return vstate->trace_instructions; | |
| 110 } | |
| 111 | |
| 112 void NaClValidatorStateSetTraceInstructions(NaClValidatorState *vstate, | |
| 113 Bool new_value) { | |
| 114 vstate->trace_instructions = new_value; | |
| 115 } | |
| 116 | |
| 117 Bool NaClValidatorStateGetTraceInstInternals(NaClValidatorState *vstate) { | |
| 118 return vstate->trace_inst_internals; | |
| 119 } | |
| 120 | |
| 121 void NaClValidatorStateSetTraceInstInternals(NaClValidatorState *vstate, | |
| 122 Bool new_value) { | |
| 123 vstate->trace_inst_internals = new_value; | |
| 124 } | |
| 125 | |
| 126 static INLINE Bool NaClValidatorStateTraceInline(NaClValidatorState *vstate) { | |
| 127 return vstate->trace_instructions || vstate->trace_inst_internals; | |
| 128 } | |
| 129 | |
| 130 | |
| 131 Bool NaClValidatorStateTrace(NaClValidatorState *vstate) { | |
| 132 return NaClValidatorStateTraceInline(vstate); | |
| 133 } | |
| 134 | |
| 135 void NaClValidatorStateSetTraceVerbose(NaClValidatorState *vstate) { | |
| 136 vstate->trace_instructions = TRUE; | |
| 137 vstate->trace_inst_internals = TRUE; | |
| 138 } | |
| 139 | |
| 140 int NaClValidatorStateGetLogVerbosity(NaClValidatorState *vstate) { | |
| 141 return vstate->log_verbosity; | |
| 142 } | |
| 143 | |
| 144 void NaClValidatorStateSetLogVerbosity(NaClValidatorState *vstate, | |
| 145 Bool new_value) { | |
| 146 vstate->log_verbosity = new_value; | |
| 147 } | |
| 148 | |
| 149 Bool NaClValidatorStateGetDoStubOut(NaClValidatorState *vstate) { | |
| 150 return vstate->do_stub_out; | |
| 151 } | |
| 152 | |
| 153 void NaClValidatorStateSetDoStubOut(NaClValidatorState *vstate, | |
| 154 Bool new_value) { | |
| 155 vstate->do_stub_out = new_value; | |
| 156 /* We also turn off error diagnostics, under the assumption | |
| 157 * you don't want them. (Note: if the user wants them, | |
| 158 * you can run ncval to get them). | |
| 159 */ | |
| 160 if (new_value) { | |
| 161 NaClValidatorStateSetMaxReportedErrors(vstate, 0); | |
| 162 } | |
| 163 } | |
| 164 | |
| 165 static void NaClValidatorTrace(NaClValidatorState* vstate) { | |
| 166 struct Gio* g = NaClLogGetGio(); | |
| 167 NaClInstState* inst_state = NaClInstIterGetStateInline(vstate->cur_iter); | |
| 168 (*vstate->error_reporter->printf) | |
| 169 (vstate->error_reporter, "-> visit: "); | |
| 170 if (NaClValidatorStateGetTraceInstructions(vstate)) { | |
| 171 (*vstate->error_reporter->print_inst)(vstate->error_reporter, | |
| 172 (void*) NaClInstStateInst(inst_state)); | |
| 173 } | |
| 174 if (NaClValidatorStateGetTraceInstInternals(vstate)) { | |
| 175 NaClExpVectorPrint(g, inst_state); | |
| 176 } | |
| 177 } | |
| 178 | |
| 179 /* TODO(karl) Move the print routines to a separate module. */ | |
| 180 | |
| 181 /* Returns true if an error message should be printed for the given level, in | |
| 182 * the current validator state. | |
| 183 * Parameters: | |
| 184 * vstate - The validator state (may be NULL). | |
| 185 * level - The log level of the validator message. | |
| 186 */ | |
| 187 static INLINE Bool NaClPrintValidatorMessages( | |
| 188 NaClValidatorState *vstate, int level) { | |
| 189 if (NULL == vstate) { | |
| 190 /* Validator not defined yet, only used log verbosity to decide if message | |
| 191 * should be printed. | |
| 192 */ | |
| 193 return level <= NaClLogGetVerbosity(); | |
| 194 } else { | |
| 195 return (vstate->quit_after_error_count != 0) && | |
| 196 (level <= vstate->log_verbosity) && | |
| 197 (level <= NaClLogGetVerbosity()); | |
| 198 } | |
| 199 } | |
| 200 | |
| 201 static INLINE const char *NaClLogLevelLabel(int level) { | |
| 202 switch (level) { | |
| 203 case LOG_WARNING: | |
| 204 return "WARNING: "; | |
| 205 case LOG_ERROR: | |
| 206 return "ERROR: "; | |
| 207 case LOG_FATAL: | |
| 208 return "FATAL: "; | |
| 209 default: | |
| 210 return ""; | |
| 211 } | |
| 212 } | |
| 213 | |
| 214 /* Records that an error message has just been reported. | |
| 215 * Parameters: | |
| 216 * vstate - The validator state (may be NULL). | |
| 217 * level - The log level of the validator message. | |
| 218 */ | |
| 219 static void NaClRecordErrorReported(NaClValidatorState *vstate, int level) { | |
| 220 if ((vstate != NULL) && ((level == LOG_ERROR) || (level == LOG_FATAL)) && | |
| 221 (vstate->quit_after_error_count > 0) && | |
| 222 !vstate->do_stub_out) { | |
| 223 --(vstate->quit_after_error_count); | |
| 224 vstate->quit = NaClValidatorQuit(vstate); | |
| 225 if (vstate->quit_after_error_count == 0) { | |
| 226 (*vstate->error_reporter->printf)( | |
| 227 vstate->error_reporter, | |
| 228 "%sError limit reached. Validator quitting!\n", | |
| 229 NaClLogLevelLabel(LOG_INFO)); | |
| 230 } | |
| 231 } | |
| 232 } | |
| 233 | |
| 234 /* Records the number of error validator messages generated for the state. | |
| 235 * Parameters: | |
| 236 * vstate - The validator state (may be NULL). | |
| 237 * level - The log level of the validator message. | |
| 238 * Returns - Updated error level, based on state. | |
| 239 */ | |
| 240 static INLINE int NaClRecordIfValidatorError(NaClValidatorState *vstate, | |
| 241 int level) { | |
| 242 /* Note: don't quit if stubbing out, so all problems are fixed. */ | |
| 243 if (((level == LOG_ERROR) || (level == LOG_FATAL)) && | |
| 244 (NULL != vstate) && !vstate->do_stub_out) { | |
| 245 vstate->validates_ok = FALSE; | |
| 246 vstate->quit = NaClValidatorQuit(vstate); | |
| 247 } | |
| 248 return level; | |
| 249 } | |
| 250 | |
| 251 /* The low-level implementation for stubbing out an instruction. Always use | |
| 252 * this function to (ultimately) stub out instructions. This makes it possible | |
| 253 * to detect when the validator modifies the code. | |
| 254 */ | |
| 255 void NCStubOutMem(NaClValidatorState *state, void *ptr, size_t num) { | |
| 256 state->did_stub_out = TRUE; | |
| 257 memset(ptr, kNaClFullStop, num); | |
| 258 } | |
| 259 | |
| 260 /* Does stub out of instruction in validator state. */ | |
| 261 static void NaClStubOutInst(NaClValidatorState *state, NaClInstState* inst) { | |
| 262 NCRemainingMemory *memory = inst->bytes.memory; | |
| 263 NCStubOutMem(state, memory->mpc, memory->read_length); | |
| 264 } | |
| 265 | |
| 266 /* Does a printf using the error reporter of the state if defined. | |
| 267 * Uses NaClLogGetGio() if undefined. | |
| 268 */ | |
| 269 static INLINE void NaClPrintVMessage(NaClValidatorState* vstate, | |
| 270 const char* format, | |
| 271 va_list ap) { | |
| 272 if (vstate) { | |
| 273 vstate->error_reporter->printf_v(vstate->error_reporter, format, ap); | |
| 274 } else { | |
| 275 gvprintf(NaClLogGetGio(), format, ap); | |
| 276 } | |
| 277 } | |
| 278 | |
| 279 /* Forward declaration to define printf arguments. */ | |
| 280 static void NaClPrintMessage(NaClValidatorState* vstate, | |
| 281 const char* format, | |
| 282 ...) ATTRIBUTE_FORMAT_PRINTF(2, 3); | |
| 283 | |
| 284 /* Does a printf using the error reporter of the state if defined. | |
| 285 * Uses NaClLogGetGio() if undefined. | |
| 286 */ | |
| 287 static INLINE void NaClPrintMessage(NaClValidatorState* vstate, | |
| 288 const char* format, | |
| 289 ...) { | |
| 290 va_list ap; | |
| 291 va_start(ap, format); | |
| 292 NaClPrintVMessage(vstate, format, ap); | |
| 293 va_end(ap); | |
| 294 } | |
| 295 | |
| 296 /* Print out a predefined prefix for messages, along with the serverity | |
| 297 * of the message. | |
| 298 */ | |
| 299 static void NaClPrintValidatorPrefix(int level, | |
| 300 NaClValidatorState* vstate, | |
| 301 Bool visible_level) { | |
| 302 NaClPrintMessage(vstate, "VALIDATOR: "); | |
| 303 if (visible_level) NaClPrintMessage(vstate, "%s", NaClLogLevelLabel(level)); | |
| 304 } | |
| 305 | |
| 306 /* Prints out an instruction on behalf of the validator. */ | |
| 307 static void NaClValidatorPrintInst(int level, | |
| 308 NaClValidatorState *vstate, | |
| 309 NaClInstState *inst) { | |
| 310 NaClPrintValidatorPrefix(level, vstate, FALSE); | |
| 311 if (vstate) { | |
| 312 vstate->error_reporter->print_inst(vstate->error_reporter, (void*) inst); | |
| 313 } else { | |
| 314 NaClInstStateInstPrint(NaClLogGetGio(), inst); | |
| 315 } | |
| 316 } | |
| 317 | |
| 318 void NaClValidatorMessage(int level, | |
| 319 NaClValidatorState *vstate, | |
| 320 const char *format, | |
| 321 ...) { | |
| 322 level = NaClRecordIfValidatorError(vstate, level); | |
| 323 if (NaClPrintValidatorMessages(vstate, level)) { | |
| 324 va_list ap; | |
| 325 NaClPrintValidatorPrefix(level, vstate, TRUE); | |
| 326 va_start(ap, format); | |
| 327 NaClPrintVMessage(vstate, format, ap); | |
| 328 va_end(ap); | |
| 329 NaClRecordErrorReported(vstate, level); | |
| 330 } | |
| 331 } | |
| 332 | |
| 333 void NaClValidatorVarargMessage(int level, | |
| 334 NaClValidatorState *vstate, | |
| 335 const char *format, | |
| 336 va_list ap) { | |
| 337 level = NaClRecordIfValidatorError(vstate, level); | |
| 338 if (NaClPrintValidatorMessages(vstate, level)) { | |
| 339 NaClPrintValidatorPrefix(level, vstate, TRUE); | |
| 340 NaClPrintVMessage(vstate, format, ap); | |
| 341 NaClRecordErrorReported(vstate, level); | |
| 342 } | |
| 343 } | |
| 344 | |
| 345 static void NaClValidatorPcAddressMess( | |
| 346 int level, | |
| 347 NaClValidatorState *vstate, | |
| 348 NaClPcAddress addr, | |
| 349 const char *format, | |
| 350 va_list ap) { | |
| 351 level = NaClRecordIfValidatorError(vstate, level); | |
| 352 if (NaClPrintValidatorMessages(vstate, level)) { | |
| 353 NaClPrintValidatorPrefix(level, vstate, !NACL_FLAGS_ncval_annotate); | |
| 354 NaClPrintMessage(vstate, "%"NACL_PRIxNaClPcAddress ": ", addr); | |
| 355 NaClPrintVMessage(vstate, format, ap); | |
| 356 NaClRecordErrorReported(vstate, level); | |
| 357 } | |
| 358 } | |
| 359 | |
| 360 void NaClValidatorPcAddressMessage(int level, | |
| 361 NaClValidatorState *vstate, | |
| 362 NaClPcAddress addr, | |
| 363 const char *format, | |
| 364 ...) { | |
| 365 va_list ap; | |
| 366 va_start(ap, format); | |
| 367 NaClValidatorPcAddressMess(level, vstate, vstate->vbase + addr, format, ap); | |
| 368 va_end(ap); | |
| 369 } | |
| 370 | |
| 371 void NaClValidatorInstMessage(int level, | |
| 372 NaClValidatorState *vstate, | |
| 373 NaClInstState *inst, | |
| 374 const char *format, | |
| 375 ...) { | |
| 376 if (NACL_FLAGS_ncval_annotate) { | |
| 377 va_list ap; | |
| 378 va_start(ap, format); | |
| 379 NaClValidatorPcAddressMess(level, vstate, | |
| 380 NaClInstStatePrintableAddress(inst), | |
| 381 format, ap); | |
| 382 va_end(ap); | |
| 383 } else { | |
| 384 level = NaClRecordIfValidatorError(vstate, level); | |
| 385 if (NaClPrintValidatorMessages(vstate, level)) { | |
| 386 va_list ap; | |
| 387 NaClValidatorPrintInst(level, vstate, inst); | |
| 388 NaClPrintValidatorPrefix(level, vstate, TRUE); | |
| 389 va_start(ap, format); | |
| 390 NaClPrintVMessage(vstate, format, ap); | |
| 391 va_end(ap); | |
| 392 NaClRecordErrorReported(vstate, level); | |
| 393 } | |
| 394 } | |
| 395 if (vstate->do_stub_out && (level <= LOG_ERROR)) { | |
| 396 NaClStubOutInst(vstate, inst); | |
| 397 } | |
| 398 } | |
| 399 | |
| 400 void NaClValidatorTwoInstMessage(int level, | |
| 401 NaClValidatorState *vstate, | |
| 402 NaClInstState *inst1, | |
| 403 NaClInstState *inst2, | |
| 404 const char *format, | |
| 405 ...) { | |
| 406 level = NaClRecordIfValidatorError(vstate, level); | |
| 407 if (NaClPrintValidatorMessages(vstate, level)) { | |
| 408 va_list ap; | |
| 409 NaClPrintValidatorPrefix(level, vstate, TRUE); | |
| 410 va_start(ap, format); | |
| 411 NaClPrintVMessage(vstate, format, ap); | |
| 412 va_end(ap); | |
| 413 NaClPrintMessage(vstate, "\n "); | |
| 414 NaClValidatorPrintInst(level, vstate, inst1); | |
| 415 NaClPrintMessage(vstate, " "); | |
| 416 NaClValidatorPrintInst(level, vstate, inst2); | |
| 417 NaClRecordErrorReported(vstate, level); | |
| 418 } | |
| 419 if (vstate->do_stub_out && (level <= LOG_ERROR)) { | |
| 420 NaClStubOutInst(vstate, inst2); | |
| 421 } | |
| 422 } | |
| 423 | |
| 424 Bool NaClValidatorQuit(NaClValidatorState *vstate) { | |
| 425 return !vstate->validates_ok && (vstate->quit_after_error_count == 0); | |
| 426 } | |
| 427 | |
| 428 Bool NaClValidatorDidStubOut(NaClValidatorState *vstate) { | |
| 429 return vstate->did_stub_out; | |
| 430 } | |
| 431 | |
| 432 static void NaClNullErrorPrintInst(NaClErrorReporter* self, | |
| 433 struct NaClInstState* inst) {} | |
| 434 | |
| 435 NaClErrorReporter kNaClNullErrorReporter = { | |
| 436 NaClNullErrorReporter, | |
| 437 NaClNullErrorPrintf, | |
| 438 NaClNullErrorPrintfV, | |
| 439 (NaClPrintInst) NaClNullErrorPrintInst | |
| 440 }; | |
| 441 | |
| 442 /* Update caches associated the current instruction state associated with | |
| 443 * the iterator of the validator state. This routine should be called everytime | |
| 444 * the iterator (of the validator state) is advanced. | |
| 445 */ | |
| 446 static INLINE void NaClUpdateCaches(NaClValidatorState *vstate) { | |
| 447 #ifdef NCVAL_TESTING | |
| 448 /* Initialize the pre/post conditions to the empty condition. */ | |
| 449 strcpy(&vstate->precond[0], ""); | |
| 450 strcpy(&vstate->postcond[0], ""); | |
| 451 #endif | |
| 452 vstate->cur_inst_state = NaClInstIterGetStateInline(vstate->cur_iter); | |
| 453 vstate->cur_inst = NaClInstStateInst(vstate->cur_inst_state); | |
| 454 vstate->cur_inst_vector = NaClInstStateExpVector(vstate->cur_inst_state); | |
| 455 } | |
| 456 | |
| 457 /* Returns true if the current position of the instruction iterator (for | |
| 458 * the validator state) points to an instruction (i.e. not at the end of | |
| 459 * the segment). | |
| 460 */ | |
| 461 static INLINE Bool NaClValidatorStateIterHasNextInline( | |
| 462 NaClValidatorState *vstate) { | |
| 463 Bool result; | |
| 464 if (NULL == vstate->cur_iter) return FALSE; | |
| 465 result = NaClInstIterHasNextInline(vstate->cur_iter); | |
| 466 if (result && NULL == vstate->cur_inst_state) { | |
| 467 /* If reached, this is the first query to check if there is | |
| 468 * a next instruction. Update the caches to match. | |
| 469 */ | |
| 470 NaClUpdateCaches(vstate); | |
| 471 } | |
| 472 return result; | |
| 473 } | |
| 474 | |
| 475 Bool NaClValidatorStateIterHasNext(NaClValidatorState *vstate) { | |
| 476 return NaClValidatorStateIterHasNextInline(vstate); | |
| 477 } | |
| 478 | |
| 479 /* Move past the current instruction defined by the iterator of the | |
| 480 * validator state. | |
| 481 */ | |
| 482 static INLINE void NaClValidatorStateIterAdvanceInline( | |
| 483 NaClValidatorState *vstate) { | |
| 484 NaClInstIterAdvanceInline(vstate->cur_iter); | |
| 485 NaClUpdateCaches(vstate); | |
| 486 } | |
| 487 | |
| 488 void NaClValidatorStateIterAdvance(NaClValidatorState *vstate) { | |
| 489 NaClValidatorStateIterAdvanceInline(vstate); | |
| 490 } | |
| 491 | |
| 492 /* Iterator of the validator state is no longer needed, clean up any | |
| 493 * caches associated with the iterator. | |
| 494 */ | |
| 495 static void NaClValidatorStateIterFinishInline(NaClValidatorState *vstate) { | |
| 496 vstate->cur_inst_state = NULL; | |
| 497 vstate->cur_inst = NULL; | |
| 498 vstate->cur_inst_vector = NULL; | |
| 499 } | |
| 500 | |
| 501 void NaClValidatorStateIterFinish(NaClValidatorState *vstate) { | |
| 502 NaClValidatorStateIterFinishInline(vstate); | |
| 503 } | |
| 504 | |
| 505 NaClValidatorState *NaClValidatorStateCreate( | |
| 506 const NaClPcAddress vbase, | |
| 507 const NaClMemorySize codesize, | |
| 508 const NaClOpKind base_register, | |
| 509 const int readonly_text, | |
| 510 const NaClCPUFeaturesX86 *features) { | |
| 511 NaClValidatorState *vstate; | |
| 512 NaClValidatorState *return_value = NULL; | |
| 513 const int bundle_size = 32; | |
| 514 DEBUG(NaClLog(LOG_INFO, | |
| 515 "Validator Create: vbase = %"NACL_PRIxNaClPcAddress", " | |
| 516 "sz = %"NACL_PRIxNaClMemorySize", bundle_size = %u\n", | |
| 517 vbase, codesize, bundle_size)); | |
| 518 if (features == NULL) | |
| 519 return NULL; | |
| 520 vstate = (NaClValidatorState*) malloc(sizeof(NaClValidatorState)); | |
| 521 if (vstate != NULL) { | |
| 522 return_value = vstate; | |
| 523 vstate->decoder_tables = kNaClValDecoderTables; | |
| 524 vstate->vbase = vbase; | |
| 525 vstate->bundle_size = bundle_size; | |
| 526 vstate->codesize = codesize; | |
| 527 vstate->bundle_mask = bundle_size - 1; | |
| 528 NaClCopyCPUFeaturesX86(&vstate->cpu_features, features); | |
| 529 vstate->base_register = base_register; | |
| 530 vstate->validates_ok = TRUE; | |
| 531 vstate->did_stub_out = FALSE; | |
| 532 vstate->quit_after_error_count = NACL_FLAGS_max_reported_errors; | |
| 533 #ifdef NCVAL_TESTING | |
| 534 vstate->validates_ok_with_conditions = TRUE; | |
| 535 vstate->report_conditions_on_all = NACL_FLAGS_report_conditions_on_all; | |
| 536 #endif | |
| 537 vstate->error_reporter = &kNaClNullErrorReporter; | |
| 538 vstate->print_opcode_histogram = NACL_FLAGS_opcode_histogram; | |
| 539 vstate->trace_instructions = NACL_FLAGS_validator_trace_instructions; | |
| 540 vstate->trace_inst_internals = NACL_FLAGS_validator_trace_inst_internals; | |
| 541 vstate->log_verbosity = LOG_INFO; | |
| 542 vstate->cur_iter = NULL; | |
| 543 NaClValidatorStateIterFinishInline(vstate); | |
| 544 vstate->quit = NaClValidatorQuit(return_value); | |
| 545 vstate->do_stub_out = FALSE; | |
| 546 vstate->readonly_text = readonly_text; | |
| 547 vstate->do_detailed = FALSE; | |
| 548 NaClOpcodeHistogramInitialize(vstate); | |
| 549 NaClCpuCheckMemoryInitialize(vstate); | |
| 550 NaClBaseRegisterMemoryInitialize(vstate); | |
| 551 if (!NaClJumpValidatorInitialize(vstate)) { | |
| 552 NaClValidatorStateDestroy(vstate); | |
| 553 return_value = NULL; | |
| 554 } | |
| 555 } | |
| 556 return return_value; | |
| 557 } | |
| 558 | |
| 559 Bool NaClValidatorStateIterReset(NaClValidatorState *vstate) { | |
| 560 /* Record infromation needed to reset the iterator, based on the | |
| 561 * current iterator | |
| 562 */ | |
| 563 size_t lookback_size = lookback_size = vstate->cur_iter->buffer_size; | |
| 564 NaClSegment* segment = vstate->cur_iter->segment; | |
| 565 | |
| 566 if (NULL == vstate->cur_iter) return FALSE; | |
| 567 | |
| 568 /* Before deleting, be sure to clean up cached information. and | |
| 569 * the destroy the current validator. */ | |
| 570 NaClValidatorStateIterFinishInline(vstate); | |
| 571 NaClInstIterDestroy(vstate->cur_iter); | |
| 572 | |
| 573 /* Now create a new instruction iterator. */ | |
| 574 vstate->cur_iter = NaClInstIterCreateWithLookback( | |
| 575 vstate->decoder_tables, segment, lookback_size); | |
| 576 | |
| 577 if (NULL == vstate->cur_iter) return FALSE; | |
| 578 return TRUE; | |
| 579 } | |
| 580 | |
| 581 #ifdef NCVAL_TESTING | |
| 582 void NaClPrintConditions(NaClValidatorState *state) { | |
| 583 /* To save space, only report on instructions that have non-empty | |
| 584 * pre/post conditions. | |
| 585 */ | |
| 586 if ((strlen(state->precond) > 0) || (strlen(state->postcond) > 0)) { | |
| 587 printf("%"NACL_PRIxNaClPcAddress": ", | |
| 588 NaClInstStatePrintableAddress(state->cur_inst_state)); | |
| 589 if ('\0' != state->precond[0]) { | |
| 590 printf("%s", state->precond); | |
| 591 } | |
| 592 if ('\0' != state->postcond[0]) { | |
| 593 if ('\0' != state->precond[0]) printf(" "); | |
| 594 printf("-> %s", state->postcond); | |
| 595 } | |
| 596 printf("\n"); | |
| 597 } | |
| 598 } | |
| 599 #endif | |
| 600 | |
| 601 /* Given we are at the instruction defined by the instruction iterator, for | |
| 602 * a segment, apply all applicable validator functions. | |
| 603 */ | |
| 604 static INLINE void NaClApplyValidators(NaClValidatorState *vstate) { | |
| 605 if (vstate->quit) return; | |
| 606 DEBUG(NaClLog(LOG_INFO, "iter state:\n"); | |
| 607 NaClInstStateInstPrint(NaClLogGetGio(), | |
| 608 NaClInstIterGetState(vstate->cur_iter))); | |
| 609 if (NaClValidatorStateTraceInline(vstate)) { | |
| 610 NaClValidatorTrace(vstate); | |
| 611 } | |
| 612 NaClCpuCheck(vstate, vstate->cur_iter); | |
| 613 NaClValidateInstructionLegal(vstate); | |
| 614 NaClBaseRegisterValidator(vstate); | |
| 615 NaClMemoryReferenceValidator(vstate); | |
| 616 NaClJumpValidator(vstate); | |
| 617 if (vstate->print_opcode_histogram) { | |
| 618 NaClOpcodeHistogramRecord(vstate); | |
| 619 } | |
| 620 #ifdef NCVAL_TESTING | |
| 621 /* Collect post conditions for instructions that are non-last. | |
| 622 * Only print pre/post conditions for valid instructions (ignoring | |
| 623 * pre/post conditions). | |
| 624 */ | |
| 625 if (NaClValidatesOk(vstate) || vstate->report_conditions_on_all) { | |
| 626 NaClAddAssignsRegisterWithZeroExtendsPostconds(vstate); | |
| 627 NaClAddLeaSafeAddressPostconds(vstate); | |
| 628 NaClPrintConditions(vstate); | |
| 629 } | |
| 630 /* Reset the exit flags, so that errors do not stop | |
| 631 * other instructions from firing errors. By reseting these flags, | |
| 632 * it allows us to only print pre/post conditions for instructions | |
| 633 * that are not marked illegal. | |
| 634 */ | |
| 635 if (!vstate->validates_ok) vstate->validates_ok_with_conditions = FALSE; | |
| 636 vstate->validates_ok = TRUE; | |
| 637 vstate->quit = FALSE; | |
| 638 #endif | |
| 639 } | |
| 640 | |
| 641 /* Given that we have just iterated through all instructions in a segment, | |
| 642 * apply post validators rules (before we collect the iterator). | |
| 643 */ | |
| 644 static INLINE void NaClApplyPostValidators(NaClValidatorState *vstate) { | |
| 645 DEBUG(NaClLog(LOG_INFO, "applying post validators...\n")); | |
| 646 if (vstate->quit || (NULL == vstate->cur_iter)) return; | |
| 647 | |
| 648 /* Before doing anything else, process remaining (forward) information | |
| 649 * stored by the validator, to see if any errors should be reported | |
| 650 * about the last instruction processed. | |
| 651 */ | |
| 652 NaClBaseRegisterSummarize(vstate); | |
| 653 | |
| 654 /* Now do the summarizing steps of the validator. */ | |
| 655 if (vstate->do_detailed) { | |
| 656 NaClJumpValidatorSummarizeDetailed(vstate); | |
| 657 } else { | |
| 658 NaClJumpValidatorSummarize(vstate); | |
| 659 } | |
| 660 if (NaClValidatorStateTrace(vstate)) { | |
| 661 (vstate->error_reporter->printf) | |
| 662 (vstate->error_reporter, "<- visit\n"); | |
| 663 } | |
| 664 } | |
| 665 | |
| 666 /* The maximum lookback for the instruction iterator of the segment. | |
| 667 * Note: Allows for two memory patterns (4 instructions for each pattern). | |
| 668 */ | |
| 669 static const size_t kLookbackSize = 8; | |
| 670 | |
| 671 void NaClValidateSegment(uint8_t *mbase, NaClPcAddress vbase, | |
| 672 NaClMemorySize size, NaClValidatorState *vstate) { | |
| 673 NaClSegment segment; | |
| 674 do { | |
| 675 /* Sanity checks */ | |
| 676 /* TODO(ncbray): remove redundant vbase/size args. */ | |
| 677 if ((vbase & vstate->bundle_mask) != 0) { | |
| 678 NaClValidatorMessage(LOG_ERROR, vstate, | |
| 679 "Code segment starts at 0x%"NACL_PRIxNaClPcAddress | |
| 680 ", which isn't aligned properly.\n", | |
| 681 vbase); | |
| 682 break; | |
| 683 } | |
| 684 if (vbase != vstate->vbase) { | |
| 685 NaClValidatorMessage(LOG_ERROR, vstate, "Mismatched vbase address\n"); | |
| 686 break; | |
| 687 } | |
| 688 if (size != vstate->codesize) { | |
| 689 NaClValidatorMessage(LOG_ERROR, vstate, "Mismatched code size\n"); | |
| 690 break; | |
| 691 } | |
| 692 if (vbase > vbase + size) { | |
| 693 NaClValidatorMessage(LOG_ERROR, vstate, "Text segment too big for given " | |
| 694 "vbase (address overflow)\n"); | |
| 695 break; | |
| 696 } | |
| 697 | |
| 698 size = NCHaltTrimSize(mbase, size, vstate->bundle_size); | |
| 699 vstate->codesize = size; | |
| 700 | |
| 701 if (size == 0) { | |
| 702 NaClValidatorMessage(LOG_ERROR, vstate, "Bad text segment (zero size)\n"); | |
| 703 break; | |
| 704 } | |
| 705 | |
| 706 NaClSegmentInitialize(mbase, vbase, size, &segment); | |
| 707 | |
| 708 vstate->cur_iter = NaClInstIterCreateWithLookback(vstate->decoder_tables, | |
| 709 &segment, kLookbackSize); | |
| 710 if (NULL == vstate->cur_iter) { | |
| 711 NaClValidatorMessage(LOG_ERROR, vstate, "Not enough memory\n"); | |
| 712 break; | |
| 713 } | |
| 714 for (; NaClValidatorStateIterHasNextInline(vstate); | |
| 715 NaClValidatorStateIterAdvanceInline(vstate)) { | |
| 716 NaClApplyValidators(vstate); | |
| 717 if (vstate->quit) break; | |
| 718 } | |
| 719 NaClValidatorStateIterFinish(vstate); | |
| 720 } while (0); | |
| 721 NaClApplyPostValidators(vstate); | |
| 722 NaClInstIterDestroy(vstate->cur_iter); | |
| 723 vstate->cur_iter = NULL; | |
| 724 if (vstate->print_opcode_histogram) { | |
| 725 NaClOpcodeHistogramPrintStats(vstate); | |
| 726 } | |
| 727 #ifdef NCVAL_TESTING | |
| 728 /* Update failure to catch instructions that may have validated | |
| 729 * incorrectly. | |
| 730 */ | |
| 731 if (vstate->validates_ok) | |
| 732 vstate->validates_ok = vstate->validates_ok_with_conditions; | |
| 733 #endif | |
| 734 } | |
| 735 | |
| 736 void NaClValidateSegmentUsingTables(uint8_t* mbase, | |
| 737 NaClPcAddress vbase, | |
| 738 NaClMemorySize sz, | |
| 739 NaClValidatorState* vstate, | |
| 740 const struct NaClDecodeTables* tables) { | |
| 741 vstate->decoder_tables = tables; | |
| 742 NaClValidateSegment(mbase, vbase, sz, vstate); | |
| 743 } | |
| 744 | |
| 745 Bool NaClValidatesOk(NaClValidatorState *vstate) { | |
| 746 return vstate->validates_ok; | |
| 747 } | |
| 748 | |
| 749 void NaClValidatorStateDestroy(NaClValidatorState *vstate) { | |
| 750 if (NULL != vstate) { | |
| 751 NaClJumpValidatorCleanUp(vstate); | |
| 752 free(vstate); | |
| 753 } | |
| 754 } | |
| 755 | |
| 756 /* | |
| 757 * Check that iter_new is a valid replacement for iter_old. | |
| 758 * If a validation error occurs, vstate->validates_ok will be set to false by | |
| 759 * NaClValidatorInstMessage when it is given LOG_ERROR, see the end of this | |
| 760 * function. | |
| 761 * Return value: TRUE if the instruction was changed, FALSE if it's identical. | |
| 762 */ | |
| 763 static Bool NaClValidateInstReplacement(NaClInstIter *iter_old, | |
| 764 NaClInstIter *iter_new, | |
| 765 struct NaClValidatorState *vstate) { | |
| 766 NaClInstState *istate_old, *istate_new; | |
| 767 NaClExpVector *exp_old, *exp_new; | |
| 768 uint32_t i; | |
| 769 Bool inst_changed = FALSE; | |
| 770 int parent_index; | |
| 771 | |
| 772 istate_old = NaClInstIterGetStateInline(iter_old); | |
| 773 istate_new = NaClInstIterGetStateInline(iter_new); | |
| 774 | |
| 775 /* Location/length must match. Assumes vbase is the same. */ | |
| 776 if (istate_new->inst_addr != istate_old->inst_addr || | |
| 777 istate_new->bytes.length != istate_old->bytes.length) { | |
| 778 NaClValidatorTwoInstMessage(LOG_ERROR, vstate, istate_old, istate_new, | |
| 779 "Code modification: instructions length/addresses do not match"); | |
| 780 inst_changed = TRUE; | |
| 781 return inst_changed; | |
| 782 } | |
| 783 | |
| 784 | |
| 785 do { | |
| 786 /* fast check if the replacement is identical */ | |
| 787 if ((istate_old->bytes.memory->read_length == | |
| 788 istate_new->bytes.memory->read_length) && | |
| 789 !memcmp(istate_old->bytes.memory->mpc, istate_new->bytes.memory->mpc, | |
| 790 istate_old->bytes.memory->read_length)) | |
| 791 return inst_changed; | |
| 792 | |
| 793 inst_changed = TRUE; | |
| 794 | |
| 795 if (istate_old->num_prefix_bytes != istate_new->num_prefix_bytes) | |
| 796 break; | |
| 797 if (istate_old->num_rex_prefixes != istate_new->num_rex_prefixes) | |
| 798 break; | |
| 799 if (istate_old->rexprefix != istate_new->rexprefix) | |
| 800 break; | |
| 801 if (istate_old->modrm != istate_new->modrm) | |
| 802 break; | |
| 803 if (istate_old->has_sib != istate_new->has_sib) | |
| 804 break; | |
| 805 if (istate_old->has_sib && istate_old->sib != istate_new->sib) | |
| 806 break; | |
| 807 if (istate_old->operand_size != istate_new->operand_size) | |
| 808 break; | |
| 809 if (istate_old->address_size != istate_new->address_size) | |
| 810 break; | |
| 811 if (istate_old->prefix_mask != istate_new->prefix_mask) | |
| 812 break; | |
| 813 | |
| 814 /* | |
| 815 * these are pointers, but they reference entries in a static table, | |
| 816 * so if the two instructions are the same, then these pointers must | |
| 817 * reference the same entry | |
| 818 */ | |
| 819 if (istate_old->inst != istate_new->inst) | |
| 820 break; | |
| 821 | |
| 822 exp_old = NaClInstStateExpVector(istate_old); | |
| 823 exp_new = NaClInstStateExpVector(istate_new); | |
| 824 | |
| 825 /* check if the instruction operands are identical */ | |
| 826 if (exp_old->number_expr_nodes != exp_new->number_expr_nodes) | |
| 827 break; | |
| 828 | |
| 829 for (i = 0; i < exp_old->number_expr_nodes; i++) { | |
| 830 /* Allow nodes that are identical. */ | |
| 831 if (exp_old->node[i].kind != exp_new->node[i].kind) goto error_exit; | |
| 832 if (exp_old->node[i].flags != exp_new->node[i].flags) goto error_exit; | |
| 833 if (exp_old->node[i].value == exp_new->node[i].value) continue; | |
| 834 | |
| 835 /* | |
| 836 * Only constant values may differ. However it is important not to | |
| 837 * allow constant modification of sandboxing instructions. Note neither | |
| 838 * of the instructions allowed for modification is used for sandboxing. | |
| 839 */ | |
| 840 if (exp_old->node[i].kind != ExprConstant) goto error_exit; | |
| 841 | |
| 842 switch (istate_old->inst->name) { | |
| 843 | |
| 844 case InstCall: | |
| 845 /* allow different constants in direct calls */ | |
| 846 if (!NaClHasBit(exp_old->node[i].flags, NACL_EFLAG(ExprJumpTarget))) | |
| 847 break; | |
| 848 parent_index = NaClGetExpParentIndex(exp_old, i); | |
| 849 if (parent_index < 0) break; | |
| 850 if (exp_old->node[parent_index].kind == OperandReference) continue; | |
| 851 break; | |
| 852 | |
| 853 case InstMov: | |
| 854 parent_index = NaClGetExpParentIndex(exp_old, i); | |
| 855 if (parent_index < 0) break; | |
| 856 switch (exp_old->node[parent_index].kind) { | |
| 857 case OperandReference: | |
| 858 /* | |
| 859 * allow different constants in operand of mov | |
| 860 * e.g. mov $rax, 0xdeadbeef | |
| 861 */ | |
| 862 if (NaClHasBit(exp_old->node[i].flags, NACL_EFLAG(ExprUsed))) | |
| 863 continue; | |
| 864 break; | |
| 865 case ExprMemOffset: | |
| 866 /* | |
| 867 * allow different displacements in memory reference of mov | |
| 868 * instructions e.g. mov $rax, [$r15+$rbx*2+0x7fff] | |
| 869 * | |
| 870 * Note: displacement is the fourth node after ExprMemOffset* | |
| 871 * node | |
| 872 */ | |
| 873 if (4 == (i - parent_index)) continue; | |
| 874 break; | |
| 875 default: | |
| 876 break; | |
| 877 } | |
| 878 break; | |
| 879 default: | |
| 880 break; | |
| 881 } | |
| 882 | |
| 883 /* If reached, we found a value that differed, and wasn't one | |
| 884 * of the expected constants that can differ. | |
| 885 */ | |
| 886 goto error_exit; | |
| 887 } | |
| 888 | |
| 889 /* This return signifies there is no error in validation. */ | |
| 890 return inst_changed; | |
| 891 } while (0); | |
| 892 | |
| 893 error_exit: | |
| 894 /* This logging function is the mechanism that sets the validator state | |
| 895 * to indicate an error. | |
| 896 */ | |
| 897 NaClValidatorTwoInstMessage(LOG_ERROR, vstate, istate_old, istate_new, | |
| 898 "Code modification: failed to modify instruction"); | |
| 899 return inst_changed; | |
| 900 } | |
| 901 | |
| 902 /* | |
| 903 * Validate a new code block as a replacement for an existing block. | |
| 904 * Note: The code location (vbase) must be bundle aligned and the segment size | |
| 905 * must also be a multiple of bundle size (checked in | |
| 906 * NaClValidateCodeReplacement).This is to ensure all NaCl psuedo-instructions | |
| 907 * and guard sequences are properly inspected and maintained. | |
| 908 */ | |
| 909 void NaClValidateSegmentPair(uint8_t *mbase_old, uint8_t *mbase_new, | |
| 910 NaClPcAddress vbase, size_t size, | |
| 911 struct NaClValidatorState *vstate) { | |
| 912 NaClSegment segment_old, segment_new; | |
| 913 NaClInstIter *iter_old = NULL; | |
| 914 NaClInstIter *iter_new = NULL; | |
| 915 | |
| 916 NaClSegmentInitialize(mbase_old, vbase, size, &segment_old); | |
| 917 NaClSegmentInitialize(mbase_new, vbase, size, &segment_new); | |
| 918 do { | |
| 919 iter_old = NaClInstIterCreateWithLookback(vstate->decoder_tables, | |
| 920 &segment_old, kLookbackSize); | |
| 921 if (NULL == iter_old) break; | |
| 922 iter_new = NaClInstIterCreateWithLookback(vstate->decoder_tables, | |
| 923 &segment_new, kLookbackSize); | |
| 924 if (NULL == iter_new) break; | |
| 925 vstate->cur_iter = iter_new; | |
| 926 while (NaClInstIterHasNextInline(iter_old) && | |
| 927 NaClValidatorStateIterHasNextInline(vstate)) { | |
| 928 vstate->cur_inst_state->unchanged = | |
| 929 !NaClValidateInstReplacement(iter_old, iter_new, vstate); | |
| 930 NaClApplyValidators(vstate); | |
| 931 if (vstate->quit) break; | |
| 932 NaClInstIterAdvanceInline(iter_old); | |
| 933 NaClValidatorStateIterAdvanceInline(vstate); | |
| 934 } | |
| 935 if (NaClInstIterHasNextInline(iter_old) || | |
| 936 NaClInstIterHasNextInline(iter_new)) { | |
| 937 NaClValidatorMessage( | |
| 938 LOG_ERROR, vstate, | |
| 939 "Code modification: code segments have different " | |
| 940 "number of instructions\n"); | |
| 941 } | |
| 942 } while (0); | |
| 943 NaClValidatorStateIterFinish(vstate); | |
| 944 NaClApplyPostValidators(vstate); | |
| 945 vstate->cur_iter = NULL; | |
| 946 NaClInstIterDestroy(iter_old); | |
| 947 NaClInstIterDestroy(iter_new); | |
| 948 } | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 625923004:
Delete old x86 validator. (Closed)
Base URL: svn://svn.chromium.org/native_client/trunk/src/native_client