1 /* 2 * COPYRIGHT: See COPYING in the top level directory 3 * PROJECT: ReactOS system libraries 4 * PURPOSE: Unwinding related functions 5 * PROGRAMMER: Timo Kreuzer (timo.kreuzer@reactos.org) 6 */ 7 8 /* INCLUDES *****************************************************************/ 9 10 #include <rtl.h> 11 12 #define NDEBUG 13 #include <debug.h> 14 15 #define UNWIND_HISTORY_TABLE_NONE 0 16 #define UNWIND_HISTORY_TABLE_GLOBAL 1 17 #define UNWIND_HISTORY_TABLE_LOCAL 2 18 19 #define UWOP_PUSH_NONVOL 0 20 #define UWOP_ALLOC_LARGE 1 21 #define UWOP_ALLOC_SMALL 2 22 #define UWOP_SET_FPREG 3 23 #define UWOP_SAVE_NONVOL 4 24 #define UWOP_SAVE_NONVOL_FAR 5 25 #if 0 // These are deprecated / not for x64 26 #define UWOP_SAVE_XMM 6 27 #define UWOP_SAVE_XMM_FAR 7 28 #else 29 #define UWOP_EPILOG 6 30 #define UWOP_SPARE_CODE 7 31 #endif 32 #define UWOP_SAVE_XMM128 8 33 #define UWOP_SAVE_XMM128_FAR 9 34 #define UWOP_PUSH_MACHFRAME 10 35 36 37 typedef unsigned char UBYTE; 38 39 typedef union _UNWIND_CODE 40 { 41 struct 42 { 43 UBYTE CodeOffset; 44 UBYTE UnwindOp:4; 45 UBYTE OpInfo:4; 46 }; 47 USHORT FrameOffset; 48 } UNWIND_CODE, *PUNWIND_CODE; 49 50 typedef struct _UNWIND_INFO 51 { 52 UBYTE Version:3; 53 UBYTE Flags:5; 54 UBYTE SizeOfProlog; 55 UBYTE CountOfCodes; 56 UBYTE FrameRegister:4; 57 UBYTE FrameOffset:4; 58 UNWIND_CODE UnwindCode[1]; 59 /* union { 60 OPTIONAL ULONG ExceptionHandler; 61 OPTIONAL ULONG FunctionEntry; 62 }; 63 OPTIONAL ULONG ExceptionData[]; 64 */ 65 } UNWIND_INFO, *PUNWIND_INFO; 66 67 /* FUNCTIONS *****************************************************************/ 68 69 /*! RtlLookupFunctionTable 70 * \brief Locates the table of RUNTIME_FUNCTION entries for a code address. 71 * \param ControlPc 72 * Address of the code, for which the table should be searched. 73 * \param ImageBase 74 * Pointer to a DWORD64 that receives the base address of the 75 * corresponding executable image. 76 * \param Length 77 * Pointer to an ULONG that receives the number of table entries 78 * present in the table. 79 */ 80 PRUNTIME_FUNCTION 81 NTAPI 82 RtlLookupFunctionTable( 83 IN DWORD64 ControlPc, 84 OUT PDWORD64 ImageBase, 85 OUT PULONG Length) 86 { 87 PVOID Table; 88 ULONG Size; 89 90 /* Find corresponding file header from code address */ 91 if (!RtlPcToFileHeader((PVOID)ControlPc, (PVOID*)ImageBase)) 92 { 93 /* Nothing found */ 94 return NULL; 95 } 96 97 /* Locate the exception directory */ 98 Table = RtlImageDirectoryEntryToData((PVOID)*ImageBase, 99 TRUE, 100 IMAGE_DIRECTORY_ENTRY_EXCEPTION, 101 &Size); 102 103 /* Return the number of entries */ 104 *Length = Size / sizeof(RUNTIME_FUNCTION); 105 106 /* Return the address of the table */ 107 return Table; 108 } 109 110 PRUNTIME_FUNCTION 111 NTAPI 112 RtlpLookupDynamicFunctionEntry( 113 _In_ DWORD64 ControlPc, 114 _Out_ PDWORD64 ImageBase, 115 _In_ PUNWIND_HISTORY_TABLE HistoryTable); 116 117 /*! RtlLookupFunctionEntry 118 * \brief Locates the RUNTIME_FUNCTION entry corresponding to a code address. 119 * \ref http://msdn.microsoft.com/en-us/library/ms680597(VS.85).aspx 120 * \todo Implement HistoryTable 121 */ 122 PRUNTIME_FUNCTION 123 NTAPI 124 RtlLookupFunctionEntry( 125 IN DWORD64 ControlPc, 126 OUT PDWORD64 ImageBase, 127 OUT PUNWIND_HISTORY_TABLE HistoryTable) 128 { 129 PRUNTIME_FUNCTION FunctionTable, FunctionEntry; 130 ULONG TableLength; 131 ULONG IndexLo, IndexHi, IndexMid; 132 133 /* Find the corresponding table */ 134 FunctionTable = RtlLookupFunctionTable(ControlPc, ImageBase, &TableLength); 135 136 /* If no table is found, try dynamic function tables */ 137 if (!FunctionTable) 138 { 139 return RtlpLookupDynamicFunctionEntry(ControlPc, ImageBase, HistoryTable); 140 } 141 142 /* Use relative virtual address */ 143 ControlPc -= *ImageBase; 144 145 /* Do a binary search */ 146 IndexLo = 0; 147 IndexHi = TableLength; 148 while (IndexHi > IndexLo) 149 { 150 IndexMid = (IndexLo + IndexHi) / 2; 151 FunctionEntry = &FunctionTable[IndexMid]; 152 153 if (ControlPc < FunctionEntry->BeginAddress) 154 { 155 /* Continue search in lower half */ 156 IndexHi = IndexMid; 157 } 158 else if (ControlPc >= FunctionEntry->EndAddress) 159 { 160 /* Continue search in upper half */ 161 IndexLo = IndexMid + 1; 162 } 163 else 164 { 165 /* ControlPc is within limits, return entry */ 166 return FunctionEntry; 167 } 168 } 169 170 /* Nothing found, return NULL */ 171 return NULL; 172 } 173 174 static 175 __inline 176 ULONG 177 UnwindOpSlots( 178 _In_ UNWIND_CODE UnwindCode) 179 { 180 static const UCHAR UnwindOpExtraSlotTable[] = 181 { 182 0, // UWOP_PUSH_NONVOL 183 1, // UWOP_ALLOC_LARGE (or 3, special cased in lookup code) 184 0, // UWOP_ALLOC_SMALL 185 0, // UWOP_SET_FPREG 186 1, // UWOP_SAVE_NONVOL 187 2, // UWOP_SAVE_NONVOL_FAR 188 1, // UWOP_EPILOG // previously UWOP_SAVE_XMM 189 2, // UWOP_SPARE_CODE // previously UWOP_SAVE_XMM_FAR 190 1, // UWOP_SAVE_XMM128 191 2, // UWOP_SAVE_XMM128_FAR 192 0, // UWOP_PUSH_MACHFRAME 193 2, // UWOP_SET_FPREG_LARGE 194 }; 195 196 if ((UnwindCode.UnwindOp == UWOP_ALLOC_LARGE) && 197 (UnwindCode.OpInfo != 0)) 198 { 199 return 3; 200 } 201 else 202 { 203 return UnwindOpExtraSlotTable[UnwindCode.UnwindOp] + 1; 204 } 205 } 206 207 static 208 __inline 209 void 210 SetReg( 211 _Inout_ PCONTEXT Context, 212 _In_ BYTE Reg, 213 _In_ DWORD64 Value) 214 { 215 ((DWORD64*)(&Context->Rax))[Reg] = Value; 216 } 217 218 static 219 __inline 220 void 221 SetRegFromStackValue( 222 _Inout_ PCONTEXT Context, 223 _Inout_opt_ PKNONVOLATILE_CONTEXT_POINTERS ContextPointers, 224 _In_ BYTE Reg, 225 _In_ PDWORD64 ValuePointer) 226 { 227 SetReg(Context, Reg, *ValuePointer); 228 if (ContextPointers != NULL) 229 { 230 ContextPointers->IntegerContext[Reg] = ValuePointer; 231 } 232 } 233 234 static 235 __inline 236 DWORD64 237 GetReg( 238 _In_ PCONTEXT Context, 239 _In_ BYTE Reg) 240 { 241 return ((DWORD64*)(&Context->Rax))[Reg]; 242 } 243 244 static 245 __inline 246 void 247 PopReg( 248 _Inout_ PCONTEXT Context, 249 _Inout_opt_ PKNONVOLATILE_CONTEXT_POINTERS ContextPointers, 250 _In_ BYTE Reg) 251 { 252 SetRegFromStackValue(Context, ContextPointers, Reg, (PDWORD64)Context->Rsp); 253 Context->Rsp += sizeof(DWORD64); 254 } 255 256 static 257 __inline 258 void 259 SetXmmReg( 260 _Inout_ PCONTEXT Context, 261 _In_ BYTE Reg, 262 _In_ M128A Value) 263 { 264 ((M128A*)(&Context->Xmm0))[Reg] = Value; 265 } 266 267 static 268 __inline 269 void 270 SetXmmRegFromStackValue( 271 _Out_ PCONTEXT Context, 272 _Inout_opt_ PKNONVOLATILE_CONTEXT_POINTERS ContextPointers, 273 _In_ BYTE Reg, 274 _In_ M128A *ValuePointer) 275 { 276 SetXmmReg(Context, Reg, *ValuePointer); 277 if (ContextPointers != NULL) 278 { 279 ContextPointers->FloatingContext[Reg] = ValuePointer; 280 } 281 } 282 283 static 284 __inline 285 M128A 286 GetXmmReg(PCONTEXT Context, BYTE Reg) 287 { 288 return ((M128A*)(&Context->Xmm0))[Reg]; 289 } 290 291 /*! RtlpTryToUnwindEpilog 292 * \brief Helper function that tries to unwind epilog instructions. 293 * \return TRUE if we have been in an epilog and it could be unwound. 294 * FALSE if the instructions were not allowed for an epilog. 295 * \ref 296 * https://docs.microsoft.com/en-us/cpp/build/unwind-procedure 297 * https://docs.microsoft.com/en-us/cpp/build/prolog-and-epilog 298 * \todo 299 * - Test and compare with Windows behaviour 300 */ 301 static 302 __inline 303 BOOLEAN 304 RtlpTryToUnwindEpilog( 305 _Inout_ PCONTEXT Context, 306 _In_ ULONG64 ControlPc, 307 _Inout_opt_ PKNONVOLATILE_CONTEXT_POINTERS ContextPointers, 308 _In_ ULONG64 ImageBase, 309 _In_ PRUNTIME_FUNCTION FunctionEntry) 310 { 311 CONTEXT LocalContext; 312 BYTE *InstrPtr; 313 DWORD Instr; 314 BYTE Reg, Mod; 315 ULONG64 EndAddress; 316 317 /* Make a local copy of the context */ 318 LocalContext = *Context; 319 320 InstrPtr = (BYTE*)ControlPc; 321 322 /* Check if first instruction of epilog is "add rsp, x" */ 323 Instr = *(DWORD*)InstrPtr; 324 if ( (Instr & 0x00fffdff) == 0x00c48148 ) 325 { 326 if ( (Instr & 0x0000ff00) == 0x8300 ) 327 { 328 /* This is "add rsp, 0x??" */ 329 LocalContext.Rsp += Instr >> 24; 330 InstrPtr += 4; 331 } 332 else 333 { 334 /* This is "add rsp, 0x???????? */ 335 LocalContext.Rsp += *(DWORD*)(InstrPtr + 3); 336 InstrPtr += 7; 337 } 338 } 339 /* Check if first instruction of epilog is "lea rsp, ..." */ 340 else if ( (Instr & 0x38fffe) == 0x208d48 ) 341 { 342 /* Get the register */ 343 Reg = (Instr >> 16) & 0x7; 344 345 /* REX.R */ 346 Reg += (Instr & 1) * 8; 347 348 LocalContext.Rsp = GetReg(&LocalContext, Reg); 349 350 /* Get addressing mode */ 351 Mod = (Instr >> 22) & 0x3; 352 if (Mod == 0) 353 { 354 /* No displacement */ 355 InstrPtr += 3; 356 } 357 else if (Mod == 1) 358 { 359 /* 1 byte displacement */ 360 LocalContext.Rsp += (LONG)(CHAR)(Instr >> 24); 361 InstrPtr += 4; 362 } 363 else if (Mod == 2) 364 { 365 /* 4 bytes displacement */ 366 LocalContext.Rsp += *(LONG*)(InstrPtr + 3); 367 InstrPtr += 7; 368 } 369 } 370 371 /* Loop the following instructions before the ret */ 372 EndAddress = FunctionEntry->EndAddress + ImageBase - 1; 373 while ((DWORD64)InstrPtr < EndAddress) 374 { 375 Instr = *(DWORD*)InstrPtr; 376 377 /* Check for a simple pop */ 378 if ( (Instr & 0xf8) == 0x58 ) 379 { 380 /* Opcode pops a basic register from stack */ 381 Reg = Instr & 0x7; 382 PopReg(&LocalContext, ContextPointers, Reg); 383 InstrPtr++; 384 continue; 385 } 386 387 /* Check for REX + pop */ 388 if ( (Instr & 0xf8fb) == 0x5841 ) 389 { 390 /* Opcode is pop r8 .. r15 */ 391 Reg = ((Instr >> 8) & 0x7) + 8; 392 PopReg(&LocalContext, ContextPointers, Reg); 393 InstrPtr += 2; 394 continue; 395 } 396 397 /* Opcode not allowed for Epilog */ 398 return FALSE; 399 } 400 401 // check for popfq 402 403 // also allow end with jmp imm, jmp [target], iretq 404 405 /* Check if we are at the ret instruction */ 406 if ((DWORD64)InstrPtr != EndAddress) 407 { 408 /* If we went past the end of the function, something is broken! */ 409 ASSERT((DWORD64)InstrPtr <= EndAddress); 410 return FALSE; 411 } 412 413 /* Make sure this is really a ret instruction */ 414 if (*InstrPtr != 0xc3) 415 { 416 return FALSE; 417 } 418 419 /* Unwind is finished, pop new Rip from Stack */ 420 LocalContext.Rip = *(DWORD64*)LocalContext.Rsp; 421 LocalContext.Rsp += sizeof(DWORD64); 422 423 *Context = LocalContext; 424 return TRUE; 425 } 426 427 /*! 428 429 \ref https://docs.microsoft.com/en-us/cpp/build/unwind-data-definitions-in-c 430 */ 431 static 432 ULONG64 433 GetEstablisherFrame( 434 _In_ PCONTEXT Context, 435 _In_ PUNWIND_INFO UnwindInfo, 436 _In_ ULONG_PTR CodeOffset) 437 { 438 ULONG i; 439 440 /* Check if we have a frame register */ 441 if (UnwindInfo->FrameRegister == 0) 442 { 443 /* No frame register means we use Rsp */ 444 return Context->Rsp; 445 } 446 447 if ((CodeOffset >= UnwindInfo->SizeOfProlog) || 448 ((UnwindInfo->Flags & UNW_FLAG_CHAININFO) != 0)) 449 { 450 return GetReg(Context, UnwindInfo->FrameRegister) - 451 UnwindInfo->FrameOffset * 16; 452 } 453 454 /* Loop all unwind ops */ 455 for (i = 0; 456 i < UnwindInfo->CountOfCodes; 457 i += UnwindOpSlots(UnwindInfo->UnwindCode[i])) 458 { 459 /* Skip codes past our code offset */ 460 if (UnwindInfo->UnwindCode[i].CodeOffset > CodeOffset) 461 { 462 continue; 463 } 464 465 /* Check for SET_FPREG */ 466 if (UnwindInfo->UnwindCode[i].UnwindOp == UWOP_SET_FPREG) 467 { 468 return GetReg(Context, UnwindInfo->FrameRegister) - 469 UnwindInfo->FrameOffset * 16; 470 } 471 } 472 473 return Context->Rsp; 474 } 475 476 PEXCEPTION_ROUTINE 477 NTAPI 478 RtlVirtualUnwind( 479 _In_ ULONG HandlerType, 480 _In_ ULONG64 ImageBase, 481 _In_ ULONG64 ControlPc, 482 _In_ PRUNTIME_FUNCTION FunctionEntry, 483 _Inout_ PCONTEXT Context, 484 _Outptr_ PVOID *HandlerData, 485 _Out_ PULONG64 EstablisherFrame, 486 _Inout_opt_ PKNONVOLATILE_CONTEXT_POINTERS ContextPointers) 487 { 488 PUNWIND_INFO UnwindInfo; 489 ULONG_PTR ControlRva, CodeOffset; 490 ULONG i, Offset; 491 UNWIND_CODE UnwindCode; 492 BYTE Reg; 493 PULONG LanguageHandler; 494 495 /* Get relative virtual address */ 496 ControlRva = ControlPc - ImageBase; 497 498 /* Sanity checks */ 499 if ( (ControlRva < FunctionEntry->BeginAddress) || 500 (ControlRva >= FunctionEntry->EndAddress) ) 501 { 502 return NULL; 503 } 504 505 /* Get a pointer to the unwind info */ 506 UnwindInfo = RVA(ImageBase, FunctionEntry->UnwindData); 507 508 /* The language specific handler data follows the unwind info */ 509 LanguageHandler = ALIGN_UP_POINTER_BY(&UnwindInfo->UnwindCode[UnwindInfo->CountOfCodes], sizeof(ULONG)); 510 511 /* Calculate relative offset to function start */ 512 CodeOffset = ControlRva - FunctionEntry->BeginAddress; 513 514 *EstablisherFrame = GetEstablisherFrame(Context, UnwindInfo, CodeOffset); 515 516 /* Check if we are in the function epilog and try to finish it */ 517 if ((CodeOffset > UnwindInfo->SizeOfProlog) && (UnwindInfo->CountOfCodes > 0)) 518 { 519 if (RtlpTryToUnwindEpilog(Context, ControlPc, ContextPointers, ImageBase, FunctionEntry)) 520 { 521 /* There's no exception routine */ 522 return NULL; 523 } 524 } 525 526 /* Skip all Ops with an offset greater than the current Offset */ 527 i = 0; 528 while ((i < UnwindInfo->CountOfCodes) && 529 (UnwindInfo->UnwindCode[i].CodeOffset > CodeOffset)) 530 { 531 i += UnwindOpSlots(UnwindInfo->UnwindCode[i]); 532 } 533 534 RepeatChainedInfo: 535 536 /* Process the remaining unwind ops */ 537 while (i < UnwindInfo->CountOfCodes) 538 { 539 UnwindCode = UnwindInfo->UnwindCode[i]; 540 switch (UnwindCode.UnwindOp) 541 { 542 case UWOP_PUSH_NONVOL: 543 Reg = UnwindCode.OpInfo; 544 PopReg(Context, ContextPointers, Reg); 545 i++; 546 break; 547 548 case UWOP_ALLOC_LARGE: 549 if (UnwindCode.OpInfo) 550 { 551 Offset = *(ULONG*)(&UnwindInfo->UnwindCode[i+1]); 552 Context->Rsp += Offset; 553 i += 3; 554 } 555 else 556 { 557 Offset = UnwindInfo->UnwindCode[i+1].FrameOffset; 558 Context->Rsp += Offset * 8; 559 i += 2; 560 } 561 break; 562 563 case UWOP_ALLOC_SMALL: 564 Context->Rsp += (UnwindCode.OpInfo + 1) * 8; 565 i++; 566 break; 567 568 case UWOP_SET_FPREG: 569 Reg = UnwindInfo->FrameRegister; 570 Context->Rsp = GetReg(Context, Reg) - UnwindInfo->FrameOffset * 16; 571 i++; 572 break; 573 574 case UWOP_SAVE_NONVOL: 575 Reg = UnwindCode.OpInfo; 576 Offset = UnwindInfo->UnwindCode[i + 1].FrameOffset; 577 SetRegFromStackValue(Context, ContextPointers, Reg, (DWORD64*)Context->Rsp + Offset); 578 i += 2; 579 break; 580 581 case UWOP_SAVE_NONVOL_FAR: 582 Reg = UnwindCode.OpInfo; 583 Offset = *(ULONG*)(&UnwindInfo->UnwindCode[i + 1]); 584 SetRegFromStackValue(Context, ContextPointers, Reg, (DWORD64*)Context->Rsp + Offset); 585 i += 3; 586 break; 587 588 case UWOP_EPILOG: 589 i += 1; 590 break; 591 592 case UWOP_SPARE_CODE: 593 ASSERT(FALSE); 594 i += 2; 595 break; 596 597 case UWOP_SAVE_XMM128: 598 Reg = UnwindCode.OpInfo; 599 Offset = UnwindInfo->UnwindCode[i + 1].FrameOffset; 600 SetXmmRegFromStackValue(Context, ContextPointers, Reg, (M128A*)Context->Rsp + Offset); 601 i += 2; 602 break; 603 604 case UWOP_SAVE_XMM128_FAR: 605 Reg = UnwindCode.OpInfo; 606 Offset = *(ULONG*)(&UnwindInfo->UnwindCode[i + 1]); 607 SetXmmRegFromStackValue(Context, ContextPointers, Reg, (M128A*)Context->Rsp + Offset); 608 i += 3; 609 break; 610 611 case UWOP_PUSH_MACHFRAME: 612 /* OpInfo is 1, when an error code was pushed, otherwise 0. */ 613 Context->Rsp += UnwindCode.OpInfo * sizeof(DWORD64); 614 615 /* Now pop the MACHINE_FRAME (RIP/RSP only. And yes, "magic numbers", deal with it) */ 616 Context->Rip = *(PDWORD64)(Context->Rsp + 0x00); 617 Context->Rsp = *(PDWORD64)(Context->Rsp + 0x18); 618 ASSERT((i + 1) == UnwindInfo->CountOfCodes); 619 goto Exit; 620 } 621 } 622 623 /* Check for chained info */ 624 if (UnwindInfo->Flags & UNW_FLAG_CHAININFO) 625 { 626 /* See https://docs.microsoft.com/en-us/cpp/build/exception-handling-x64?view=msvc-160#chained-unwind-info-structures */ 627 FunctionEntry = (PRUNTIME_FUNCTION)&(UnwindInfo->UnwindCode[(UnwindInfo->CountOfCodes + 1) & ~1]); 628 UnwindInfo = RVA(ImageBase, FunctionEntry->UnwindData); 629 i = 0; 630 goto RepeatChainedInfo; 631 } 632 633 /* Unwind is finished, pop new Rip from Stack */ 634 if (Context->Rsp != 0) 635 { 636 Context->Rip = *(DWORD64*)Context->Rsp; 637 Context->Rsp += sizeof(DWORD64); 638 } 639 640 Exit: 641 642 /* Check if we have a handler and return it */ 643 if (UnwindInfo->Flags & (HandlerType & (UNW_FLAG_EHANDLER | UNW_FLAG_UHANDLER))) 644 { 645 *HandlerData = (LanguageHandler + 1); 646 return RVA(ImageBase, *LanguageHandler); 647 } 648 649 return NULL; 650 } 651 652 /*! 653 \remark The implementation is based on the description in this blog: http://www.nynaeve.net/?p=106 654 655 Differences to the desciption: 656 - Instead of using 2 pointers to the unwind context and previous context, 657 that are being swapped and the context copied, the unwind context is 658 kept in the local context and copied back into the context passed in 659 by the caller. 660 661 \see http://www.nynaeve.net/?p=106 662 */ 663 BOOLEAN 664 NTAPI 665 RtlpUnwindInternal( 666 _In_opt_ PVOID TargetFrame, 667 _In_opt_ PVOID TargetIp, 668 _In_ PEXCEPTION_RECORD ExceptionRecord, 669 _In_ PVOID ReturnValue, 670 _In_ PCONTEXT ContextRecord, 671 _In_opt_ struct _UNWIND_HISTORY_TABLE *HistoryTable, 672 _In_ ULONG HandlerType) 673 { 674 DISPATCHER_CONTEXT DispatcherContext; 675 PEXCEPTION_ROUTINE ExceptionRoutine; 676 EXCEPTION_DISPOSITION Disposition; 677 PRUNTIME_FUNCTION FunctionEntry; 678 ULONG_PTR StackLow, StackHigh; 679 ULONG64 ImageBase, EstablisherFrame; 680 CONTEXT UnwindContext; 681 682 /* Get the current stack limits */ 683 RtlpGetStackLimits(&StackLow, &StackHigh); 684 685 /* If we have a target frame, then this is our high limit */ 686 if (TargetFrame != NULL) 687 { 688 StackHigh = (ULONG64)TargetFrame + 1; 689 } 690 691 /* Copy the context */ 692 UnwindContext = *ContextRecord; 693 694 /* Set up the constant fields of the dispatcher context */ 695 DispatcherContext.ContextRecord = &UnwindContext; 696 DispatcherContext.HistoryTable = HistoryTable; 697 DispatcherContext.TargetIp = (ULONG64)TargetIp; 698 699 /* Start looping */ 700 while (TRUE) 701 { 702 /* Lookup the FunctionEntry for the current RIP */ 703 FunctionEntry = RtlLookupFunctionEntry(UnwindContext.Rip, &ImageBase, NULL); 704 if (FunctionEntry == NULL) 705 { 706 /* No function entry, so this must be a leaf function. Pop the return address from the stack. 707 Note: this can happen after the first frame as the result of an exception */ 708 UnwindContext.Rip = *(DWORD64*)UnwindContext.Rsp; 709 UnwindContext.Rsp += sizeof(DWORD64); 710 711 if (HandlerType == UNW_FLAG_UHANDLER) 712 { 713 /* Copy the context back for the next iteration */ 714 *ContextRecord = UnwindContext; 715 } 716 continue; 717 } 718 719 /* Save Rip before the virtual unwind */ 720 DispatcherContext.ControlPc = UnwindContext.Rip; 721 722 /* Do a virtual unwind to get the next frame */ 723 ExceptionRoutine = RtlVirtualUnwind(HandlerType, 724 ImageBase, 725 UnwindContext.Rip, 726 FunctionEntry, 727 &UnwindContext, 728 &DispatcherContext.HandlerData, 729 &EstablisherFrame, 730 NULL); 731 732 /* Check, if we are still within the stack boundaries */ 733 if ((EstablisherFrame < StackLow) || 734 (EstablisherFrame >= StackHigh) || 735 (EstablisherFrame & 7)) 736 { 737 /// TODO: Handle DPC stack 738 739 /* If we are handling an exception, we are done here. */ 740 if (HandlerType == UNW_FLAG_EHANDLER) 741 { 742 ExceptionRecord->ExceptionFlags |= EXCEPTION_STACK_INVALID; 743 return FALSE; 744 } 745 746 __debugbreak(); 747 RtlRaiseStatus(STATUS_BAD_STACK); 748 } 749 750 /* Check if we have an exception routine */ 751 if (ExceptionRoutine != NULL) 752 { 753 /* Check if this is the target frame */ 754 if (EstablisherFrame == (ULONG64)TargetFrame) 755 { 756 /* Set flag to inform the language handler */ 757 ExceptionRecord->ExceptionFlags |= EXCEPTION_TARGET_UNWIND; 758 } 759 760 /* Log the exception if it's enabled */ 761 RtlpCheckLogException(ExceptionRecord, 762 &UnwindContext, 763 &DispatcherContext, 764 sizeof(DispatcherContext)); 765 766 /* Set up the variable fields of the dispatcher context */ 767 DispatcherContext.ImageBase = ImageBase; 768 DispatcherContext.FunctionEntry = FunctionEntry; 769 DispatcherContext.LanguageHandler = ExceptionRoutine; 770 DispatcherContext.EstablisherFrame = EstablisherFrame; 771 DispatcherContext.ScopeIndex = 0; 772 773 /* Store the return value in the unwind context */ 774 UnwindContext.Rax = (ULONG64)ReturnValue; 775 776 /* Loop all nested handlers */ 777 do 778 { 779 /// TODO: call RtlpExecuteHandlerForUnwind instead 780 /* Call the language specific handler */ 781 Disposition = ExceptionRoutine(ExceptionRecord, 782 (PVOID)EstablisherFrame, 783 ContextRecord, 784 &DispatcherContext); 785 786 /* Clear exception flags for the next iteration */ 787 ExceptionRecord->ExceptionFlags &= ~(EXCEPTION_TARGET_UNWIND | 788 EXCEPTION_COLLIDED_UNWIND); 789 790 /* Check if we do exception handling */ 791 if (HandlerType == UNW_FLAG_EHANDLER) 792 { 793 if (Disposition == ExceptionContinueExecution) 794 { 795 /* Check if it was non-continuable */ 796 if (ExceptionRecord->ExceptionFlags & EXCEPTION_NONCONTINUABLE) 797 { 798 __debugbreak(); 799 RtlRaiseStatus(EXCEPTION_NONCONTINUABLE_EXCEPTION); 800 } 801 802 /* Execution continues */ 803 return TRUE; 804 } 805 else if (Disposition == ExceptionNestedException) 806 { 807 /// TODO 808 __debugbreak(); 809 } 810 } 811 812 if (Disposition == ExceptionCollidedUnwind) 813 { 814 /// TODO 815 __debugbreak(); 816 } 817 818 /* This must be ExceptionContinueSearch now */ 819 if (Disposition != ExceptionContinueSearch) 820 { 821 __debugbreak(); 822 RtlRaiseStatus(STATUS_INVALID_DISPOSITION); 823 } 824 } while (ExceptionRecord->ExceptionFlags & EXCEPTION_COLLIDED_UNWIND); 825 } 826 827 /* Check, if we have left our stack (8.) */ 828 if ((EstablisherFrame < StackLow) || 829 (EstablisherFrame > StackHigh) || 830 (EstablisherFrame & 7)) 831 { 832 /// TODO: Check for DPC stack 833 __debugbreak(); 834 835 if (UnwindContext.Rip == ContextRecord->Rip) 836 { 837 RtlRaiseStatus(STATUS_BAD_FUNCTION_TABLE); 838 } 839 else 840 { 841 ZwRaiseException(ExceptionRecord, ContextRecord, FALSE); 842 } 843 } 844 845 if (EstablisherFrame == (ULONG64)TargetFrame) 846 { 847 break; 848 } 849 850 if (HandlerType == UNW_FLAG_UHANDLER) 851 { 852 /* We have successfully unwound a frame. Copy the unwind context back. */ 853 *ContextRecord = UnwindContext; 854 } 855 } 856 857 if (ExceptionRecord->ExceptionCode != STATUS_UNWIND_CONSOLIDATE) 858 { 859 ContextRecord->Rip = (ULONG64)TargetIp; 860 } 861 862 /* Set the return value */ 863 ContextRecord->Rax = (ULONG64)ReturnValue; 864 865 /* Restore the context */ 866 RtlRestoreContext(ContextRecord, ExceptionRecord); 867 868 /* Should never get here! */ 869 ASSERT(FALSE); 870 return FALSE; 871 } 872 873 VOID 874 NTAPI 875 RtlUnwindEx( 876 _In_opt_ PVOID TargetFrame, 877 _In_opt_ PVOID TargetIp, 878 _In_opt_ PEXCEPTION_RECORD ExceptionRecord, 879 _In_ PVOID ReturnValue, 880 _In_ PCONTEXT ContextRecord, 881 _In_opt_ struct _UNWIND_HISTORY_TABLE *HistoryTable) 882 { 883 EXCEPTION_RECORD LocalExceptionRecord; 884 885 /* Capture the current context */ 886 RtlCaptureContext(ContextRecord); 887 888 /* Check if we have an exception record */ 889 if (ExceptionRecord == NULL) 890 { 891 /* No exception record was passed, so set up a local one */ 892 LocalExceptionRecord.ExceptionCode = STATUS_UNWIND; 893 LocalExceptionRecord.ExceptionAddress = (PVOID)ContextRecord->Rip; 894 LocalExceptionRecord.ExceptionRecord = NULL; 895 LocalExceptionRecord.NumberParameters = 0; 896 ExceptionRecord = &LocalExceptionRecord; 897 } 898 899 /* Set unwind flags */ 900 ExceptionRecord->ExceptionFlags = EXCEPTION_UNWINDING; 901 if (TargetFrame == NULL) 902 { 903 ExceptionRecord->ExceptionFlags |= EXCEPTION_EXIT_UNWIND; 904 } 905 906 /* Call the internal function */ 907 RtlpUnwindInternal(TargetFrame, 908 TargetIp, 909 ExceptionRecord, 910 ReturnValue, 911 ContextRecord, 912 HistoryTable, 913 UNW_FLAG_UHANDLER); 914 } 915 916 VOID 917 NTAPI 918 RtlUnwind( 919 _In_opt_ PVOID TargetFrame, 920 _In_opt_ PVOID TargetIp, 921 _In_opt_ PEXCEPTION_RECORD ExceptionRecord, 922 _In_ PVOID ReturnValue) 923 { 924 CONTEXT Context; 925 926 RtlUnwindEx(TargetFrame, 927 TargetIp, 928 ExceptionRecord, 929 ReturnValue, 930 &Context, 931 NULL); 932 } 933 934 ULONG 935 NTAPI 936 RtlWalkFrameChain(OUT PVOID *Callers, 937 IN ULONG Count, 938 IN ULONG Flags) 939 { 940 CONTEXT Context; 941 ULONG64 ControlPc, ImageBase, EstablisherFrame; 942 ULONG64 StackLow, StackHigh; 943 PVOID HandlerData; 944 ULONG i, FramesToSkip; 945 PRUNTIME_FUNCTION FunctionEntry; 946 MODE CurrentMode = RtlpGetMode(); 947 948 DPRINT("Enter RtlWalkFrameChain\n"); 949 950 /* The upper bits in Flags define how many frames to skip */ 951 FramesToSkip = Flags >> 8; 952 953 /* Capture the current Context */ 954 RtlCaptureContext(&Context); 955 ControlPc = Context.Rip; 956 957 /* Get the stack limits */ 958 RtlpGetStackLimits(&StackLow, &StackHigh); 959 960 _SEH2_TRY 961 { 962 /* Loop the frames */ 963 for (i = 0; i < FramesToSkip + Count; i++) 964 { 965 /* Lookup the FunctionEntry for the current ControlPc */ 966 FunctionEntry = RtlLookupFunctionEntry(ControlPc, &ImageBase, NULL); 967 968 /* Is this a leaf function? */ 969 if (!FunctionEntry) 970 { 971 Context.Rip = *(DWORD64*)Context.Rsp; 972 Context.Rsp += sizeof(DWORD64); 973 DPRINT("leaf funtion, new Rip = %p, new Rsp = %p\n", (PVOID)Context.Rip, (PVOID)Context.Rsp); 974 } 975 else 976 { 977 RtlVirtualUnwind(UNW_FLAG_NHANDLER, 978 ImageBase, 979 ControlPc, 980 FunctionEntry, 981 &Context, 982 &HandlerData, 983 &EstablisherFrame, 984 NULL); 985 DPRINT("normal funtion, new Rip = %p, new Rsp = %p\n", (PVOID)Context.Rip, (PVOID)Context.Rsp); 986 } 987 988 /* Check if we are in kernel mode */ 989 if (CurrentMode == KernelMode) 990 { 991 /* Check if we left the kernel range */ 992 if (Context.Rip < 0xFFFF800000000000ULL) 993 { 994 /* Bail out, unless user mode was requested */ 995 if ((Flags & 1) == 0) 996 { 997 break; 998 } 999 1000 /* We are in user mode now, get UM stack bounds */ 1001 CurrentMode = UserMode; 1002 StackLow = (ULONG64)NtCurrentTeb()->NtTib.StackLimit; 1003 StackHigh = (ULONG64)NtCurrentTeb()->NtTib.StackBase; 1004 } 1005 } 1006 1007 /* Check (again) if we are in user mode now */ 1008 if (CurrentMode == UserMode) 1009 { 1010 /* Check if we left the user range */ 1011 if ((Context.Rip < 0x10000) || 1012 (Context.Rip > 0x000007FFFFFEFFFFULL)) 1013 { 1014 break; 1015 } 1016 } 1017 1018 /* Check, if we have left our stack */ 1019 if ((Context.Rsp <= StackLow) || (Context.Rsp >= StackHigh)) 1020 { 1021 break; 1022 } 1023 1024 /* Continue with new Rip */ 1025 ControlPc = Context.Rip; 1026 1027 /* Save value, if we are past the frames to skip */ 1028 if (i >= FramesToSkip) 1029 { 1030 Callers[i - FramesToSkip] = (PVOID)ControlPc; 1031 } 1032 } 1033 } 1034 _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER) 1035 { 1036 DPRINT1("Exception while getting callers!\n"); 1037 i = 0; 1038 } 1039 _SEH2_END; 1040 1041 DPRINT("RtlWalkFrameChain returns %ld\n", i); 1042 return i; 1043 } 1044 1045 /*! RtlGetCallersAddress 1046 * \ref http://undocumented.ntinternals.net/UserMode/Undocumented%20Functions/Debug/RtlGetCallersAddress.html 1047 */ 1048 #undef RtlGetCallersAddress 1049 VOID 1050 NTAPI 1051 RtlGetCallersAddress( 1052 OUT PVOID *CallersAddress, 1053 OUT PVOID *CallersCaller ) 1054 { 1055 PVOID Callers[4]; 1056 ULONG Number; 1057 1058 /* Get callers: 1059 * RtlWalkFrameChain -> RtlGetCallersAddress -> x -> y */ 1060 Number = RtlWalkFrameChain(Callers, 4, 0); 1061 1062 *CallersAddress = (Number >= 3) ? Callers[2] : NULL; 1063 *CallersCaller = (Number == 4) ? Callers[3] : NULL; 1064 1065 return; 1066 } 1067 1068 static 1069 VOID 1070 RtlpCaptureNonVolatileContextPointers( 1071 _Out_ PKNONVOLATILE_CONTEXT_POINTERS NonvolatileContextPointers, 1072 _In_ ULONG64 TargetFrame) 1073 { 1074 CONTEXT Context; 1075 PRUNTIME_FUNCTION FunctionEntry; 1076 ULONG64 ImageBase; 1077 PVOID HandlerData; 1078 ULONG64 EstablisherFrame; 1079 1080 /* Zero out the nonvolatile context pointers */ 1081 RtlZeroMemory(NonvolatileContextPointers, sizeof(*NonvolatileContextPointers)); 1082 1083 /* Capture the current context */ 1084 RtlCaptureContext(&Context); 1085 1086 do 1087 { 1088 /* Make sure nothing fishy is going on. Currently this is for kernel mode only. */ 1089 ASSERT((LONG64)Context.Rip < 0); 1090 ASSERT((LONG64)Context.Rsp < 0); 1091 1092 /* Look up the function entry */ 1093 FunctionEntry = RtlLookupFunctionEntry(Context.Rip, &ImageBase, NULL); 1094 if (FunctionEntry != NULL) 1095 { 1096 /* Do a virtual unwind to the caller and capture saved non-volatiles */ 1097 RtlVirtualUnwind(UNW_FLAG_EHANDLER, 1098 ImageBase, 1099 Context.Rip, 1100 FunctionEntry, 1101 &Context, 1102 &HandlerData, 1103 &EstablisherFrame, 1104 NonvolatileContextPointers); 1105 1106 ASSERT(EstablisherFrame != 0); 1107 } 1108 else 1109 { 1110 Context.Rip = *(PULONG64)Context.Rsp; 1111 Context.Rsp += 8; 1112 } 1113 1114 /* Continue until we reach user mode */ 1115 } while ((LONG64)Context.Rip < 0); 1116 1117 /* If the caller did the right thing, we should get past the target frame */ 1118 ASSERT(EstablisherFrame >= TargetFrame); 1119 } 1120 1121 VOID 1122 RtlSetUnwindContext( 1123 _In_ PCONTEXT Context, 1124 _In_ DWORD64 TargetFrame) 1125 { 1126 KNONVOLATILE_CONTEXT_POINTERS ContextPointers; 1127 1128 /* Capture pointers to the non-volatiles up to the target frame */ 1129 RtlpCaptureNonVolatileContextPointers(&ContextPointers, TargetFrame); 1130 1131 /* Copy the nonvolatiles to the captured locations */ 1132 *ContextPointers.R12 = Context->R12; 1133 *ContextPointers.R13 = Context->R13; 1134 *ContextPointers.R14 = Context->R14; 1135 *ContextPointers.R15 = Context->R15; 1136 *ContextPointers.Xmm6 = Context->Xmm6; 1137 *ContextPointers.Xmm7 = Context->Xmm7; 1138 *ContextPointers.Xmm8 = Context->Xmm8; 1139 *ContextPointers.Xmm9 = Context->Xmm9; 1140 *ContextPointers.Xmm10 = Context->Xmm10; 1141 *ContextPointers.Xmm11 = Context->Xmm11; 1142 *ContextPointers.Xmm12 = Context->Xmm12; 1143 *ContextPointers.Xmm13 = Context->Xmm13; 1144 *ContextPointers.Xmm14 = Context->Xmm14; 1145 *ContextPointers.Xmm15 = Context->Xmm15; 1146 } 1147 1148 VOID 1149 RtlpRestoreContextInternal( 1150 _In_ PCONTEXT ContextRecord); 1151 1152 VOID 1153 RtlRestoreContext( 1154 _In_ PCONTEXT ContextRecord, 1155 _In_ PEXCEPTION_RECORD ExceptionRecord) 1156 { 1157 if (ExceptionRecord != NULL) 1158 { 1159 if ((ExceptionRecord->ExceptionCode == STATUS_UNWIND_CONSOLIDATE) && 1160 (ExceptionRecord->NumberParameters >= 1)) 1161 { 1162 PVOID (*Consolidate)(EXCEPTION_RECORD*) = (PVOID)ExceptionRecord->ExceptionInformation[0]; 1163 // FIXME: This should be called through an asm wrapper to allow handling recursive unwinding 1164 ContextRecord->Rip = (ULONG64)Consolidate(ExceptionRecord); 1165 } 1166 } 1167 1168 RtlpRestoreContextInternal(ContextRecord); 1169 } 1170