diff options
Diffstat (limited to 'src/VBox/Runtime/common/compiler/vcc/except-x86-vcc.cpp')
| -rw-r--r-- | src/VBox/Runtime/common/compiler/vcc/except-x86-vcc.cpp | 329 |
1 files changed, 329 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/compiler/vcc/except-x86-vcc.cpp b/src/VBox/Runtime/common/compiler/vcc/except-x86-vcc.cpp new file mode 100644 index 00000000..17dd3a0d --- /dev/null +++ b/src/VBox/Runtime/common/compiler/vcc/except-x86-vcc.cpp @@ -0,0 +1,329 @@ +/* $Id: except-x86-vcc.cpp $ */ +/** @file + * IPRT - Visual C++ Compiler - x86 Exception Handler Filter. + */ + +/* + * Copyright (C) 2006-2023 Oracle and/or its affiliates. + * + * This file is part of VirtualBox base platform packages, as + * available from https://www.virtualbox.org. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, in version 3 of the + * License. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <https://www.gnu.org/licenses>. + * + * The contents of this file may alternatively be used under the terms + * of the Common Development and Distribution License Version 1.0 + * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included + * in the VirtualBox distribution, in which case the provisions of the + * CDDL are applicable instead of those of the GPL. + * + * You may elect to license modified versions of this file under the + * terms and conditions of either the GPL or the CDDL or both. + * + * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 + */ + + +/********************************************************************************************************************************* +* Header Files * +*********************************************************************************************************************************/ +#include <iprt/nt/nt-and-windows.h> + +#include "internal/compiler-vcc.h" +#include "except-vcc.h" + + +/********************************************************************************************************************************* +* Structures and Typedefs * +*********************************************************************************************************************************/ +/** + * Extended exception registration record used by rtVccEh4DoLocalUnwind + * and rtVccEh4DoLocalUnwindHandler. + */ +typedef struct EH4_LOCAL_UNWIND_XCPT_REG +{ + /** Security cookie. */ + uintptr_t uEHCookieFront; + /** The actual registration record. */ + EXCEPTION_REGISTRATION_RECORD XcptRegRec; + /** @name rtVccEh4DoLocalUnwind parameters + * @{ */ + PEH4_XCPT_REG_REC_T pEh4XcptRegRec; + uint32_t uTargetTryLevel; + uint8_t const *pbFrame; + /** @} */ + /** Security cookie. */ + uintptr_t uEHCookieBack; +} EH4_LOCAL_UNWIND_XCPT_REG; + + + +/********************************************************************************************************************************* +* Global Variables * +*********************************************************************************************************************************/ +extern "C" uintptr_t __security_cookie; + + +/********************************************************************************************************************************* +* Internal Functions * +*********************************************************************************************************************************/ +DECLASM(LONG) rtVccEh4DoFiltering(PFN_EH4_XCPT_FILTER_T pfnFilter, uint8_t const *pbFrame); +DECLASM(DECL_NO_RETURN(void)) rtVccEh4JumpToHandler(PFN_EH4_XCPT_HANDLER_T pfnHandler, uint8_t const *pbFrame); +DECLASM(void) rtVccEh4DoGlobalUnwind(PEXCEPTION_RECORD pXcptRec, PEXCEPTION_REGISTRATION_RECORD pXcptRegRec); +DECLASM(void) rtVccEh4DoFinally(PFN_EH4_FINALLY_T pfnFinally, bool fAbend, uint8_t const *pbFrame); +extern "C" EXCEPTION_DISPOSITION __stdcall +rtVccEh4DoLocalUnwindHandler(PEXCEPTION_RECORD pXcptRec, PVOID pvEstFrame, PCONTEXT pCpuCtx, PVOID pvDispCtx); + + +#ifdef _MSC_VER +# pragma warning(push) +# pragma warning(disable:4733) /* warning C4733: Inline asm assigning to 'FS:0': handler not registered as safe handler */ +#endif + +/** + * Calls the __finally blocks up to @a uTargetTryLevel is reached, starting with + * @a pEh4XcptRegRec->uTryLevel. + * + * @param pEh4XcptRegRec The EH4 exception registration record. + * @param uTargetTryLevel The target __try level to stop unwinding at. + * @param pbFrame The frame pointer (EBP). + */ +static void rtVccEh4DoLocalUnwind(PEH4_XCPT_REG_REC_T pEh4XcptRegRec, uint32_t uTargetTryLevel, uint8_t const *pbFrame) +{ + /* + * Manually set up exception handler. + */ + EH4_LOCAL_UNWIND_XCPT_REG RegRec = + { + __security_cookie ^ (uintptr_t)&RegRec, + { + (EXCEPTION_REGISTRATION_RECORD *)__readfsdword(RT_UOFFSETOF(NT_TIB, ExceptionList)), + rtVccEh4DoLocalUnwindHandler /* safeseh (.sxdata) entry emitted by except-x86-vcc-asm.asm */ + }, + pEh4XcptRegRec, + uTargetTryLevel, + pbFrame, + __security_cookie ^ (uintptr_t)&RegRec + }; + __writefsdword(RT_UOFFSETOF(NT_TIB, ExceptionList), (uintptr_t)&RegRec.XcptRegRec); + + /* + * Do the unwinding. + */ + uint32_t uCurTryLevel = pEh4XcptRegRec->uTryLevel; + while ( uCurTryLevel != EH4_TOPMOST_TRY_LEVEL + && ( uCurTryLevel > uTargetTryLevel + || uTargetTryLevel == EH4_TOPMOST_TRY_LEVEL /* if we knew what 0xffffffff meant, this could probably be omitted */ )) + { + PCEH4_SCOPE_TAB_T const pScopeTable = (PCEH4_SCOPE_TAB_T)(pEh4XcptRegRec->uEncodedScopeTable ^ __security_cookie); + PCEH4_SCOPE_TAB_REC_T const pEntry = &pScopeTable->aScopeRecords[uCurTryLevel]; + + pEh4XcptRegRec->uTryLevel = uCurTryLevel = pEntry->uEnclosingLevel; + + /* __finally scope table entries have no filter sub-function. */ + if (!pEntry->pfnFilter) + { + //RTAssertMsg2("rtVccEh4DoLocalUnwind: Calling %p (level %#x)\n", pEntry->pfnFinally, uCurTryLevel); + rtVccEh4DoFinally(pEntry->pfnFinally, true /*fAbend*/, pbFrame); + + /* Read the try level again in case it changed... */ + uCurTryLevel = pEh4XcptRegRec->uTryLevel; + } + } + + /* + * Deregister exception handler. + */ + __writefsdword(RT_UOFFSETOF(NT_TIB, ExceptionList), (uintptr_t)RegRec.XcptRegRec.Next); +} + +#ifdef _MSC_VER +# pragma warning(pop) +#endif + +/** + * Exception handler for rtVccEh4DoLocalUnwind. + */ +EXCEPTION_DISPOSITION __stdcall +rtVccEh4DoLocalUnwindHandler(PEXCEPTION_RECORD pXcptRec, PVOID pvEstFrame, PCONTEXT pCpuCtx, PVOID pvDispCtx) +{ + EH4_LOCAL_UNWIND_XCPT_REG *pMyRegRec = RT_FROM_MEMBER(pvEstFrame, EH4_LOCAL_UNWIND_XCPT_REG, XcptRegRec); + __security_check_cookie(pMyRegRec->uEHCookieFront ^ (uintptr_t)pMyRegRec); + __security_check_cookie(pMyRegRec->uEHCookieBack ^ (uintptr_t)pMyRegRec); + + /* + * This is a little sketchy as it isn't all that well documented by the OS + * vendor, but if invoked while unwinding, we return ExceptionCollidedUnwind + * and update the *ppDispCtx value to point to the colliding one. + */ + if (pXcptRec->ExceptionFlags & (EXCEPTION_UNWINDING | EXCEPTION_EXIT_UNWIND)) + { + rtVccEh4DoLocalUnwind(pMyRegRec->pEh4XcptRegRec, pMyRegRec->uTargetTryLevel, pMyRegRec->pbFrame); + + PEXCEPTION_REGISTRATION_RECORD *ppDispCtx = (PEXCEPTION_REGISTRATION_RECORD *)pvDispCtx; + *ppDispCtx = &pMyRegRec->XcptRegRec; + return ExceptionCollidedUnwind; + } + + /* + * In all other cases we do nothing special. + */ + RT_NOREF(pCpuCtx); + return ExceptionContinueSearch; +} + + +/** + * This validates the CPU context, may terminate the application if invalid. + */ +DECLINLINE(void) rtVccValidateExceptionContextRecord(PCONTEXT pCpuCtx) +{ + if (RT_LIKELY( !rtVccIsGuardICallChecksActive() + || rtVccIsPointerOnTheStack(pCpuCtx->Esp))) + { /* likely */ } + else + rtVccCheckContextFailed(pCpuCtx); +} + + +/** + * Helper that validates stack cookies. + */ +DECLINLINE(void) rtVccEh4ValidateCookies(PCEH4_SCOPE_TAB_T pScopeTable, uint8_t const *pbFrame) +{ + if (pScopeTable->offGSCookie != EH4_NO_GS_COOKIE) + { + uintptr_t uGsCookie = *(uintptr_t const *)&pbFrame[pScopeTable->offGSCookie]; + uGsCookie ^= (uintptr_t)&pbFrame[pScopeTable->offGSCookieXor]; + __security_check_cookie(uGsCookie); + } + + uintptr_t uEhCookie = *(uintptr_t const *)&pbFrame[pScopeTable->offEHCookie]; + uEhCookie ^= (uintptr_t)&pbFrame[pScopeTable->offEHCookieXor]; + __security_check_cookie(uEhCookie); +} + + +/** + * Call exception filters, handlers and unwind code for x86 code. + * + * This is called for windows' structured exception handling (SEH) in x86 32-bit + * code, i.e. the __try/__except/__finally stuff in Visual C++. The compiler + * generate scope records for the __try/__except blocks as well as unwind + * records for __finally and probably C++ stack object destructors. + * + * @returns Exception disposition. + * @param pXcptRec The exception record. + * @param pXcptRegRec The exception registration record, taken to be the frame + * address. + * @param pCpuCtx The CPU context for the exception. + * @param pDispCtx Dispatcher context. + */ +extern "C" __declspec(guard(suppress)) +DWORD _except_handler4(PEXCEPTION_RECORD pXcptRec, PEXCEPTION_REGISTRATION_RECORD pXcptRegRec, PCONTEXT pCpuCtx, PVOID pvCtx) +{ + /* + * The registration record (probably chained on FS:[0] like in the OS/2 days) + * points to a larger structure specific to _except_handler4. The structure + * is planted right after the saved caller EBP value when establishing the + * stack frame, so EBP = pXcptRegRec + 1; + */ + PEH4_XCPT_REG_REC_T const pEh4XcptRegRec = RT_FROM_MEMBER(pXcptRegRec, EH4_XCPT_REG_REC_T, XcptRec); + uint8_t * const pbFrame = (uint8_t *)&pEh4XcptRegRec[1]; + PCEH4_SCOPE_TAB_T const pScopeTable = (PCEH4_SCOPE_TAB_T)(pEh4XcptRegRec->uEncodedScopeTable ^ __security_cookie); + + /* + * Validate the stack cookie and exception context. + */ + rtVccEh4ValidateCookies(pScopeTable, pbFrame); + rtVccValidateExceptionContextRecord(pCpuCtx); + + /* + * If dispatching an exception, call the exception filter functions and jump + * to the __except blocks if so directed. + */ + if (IS_DISPATCHING(pXcptRec->ExceptionFlags)) + { + uint32_t uTryLevel = pEh4XcptRegRec->uTryLevel; + //RTAssertMsg2("_except_handler4: dispatch: uTryLevel=%#x\n", uTryLevel); + while (uTryLevel != EH4_TOPMOST_TRY_LEVEL) + { + PCEH4_SCOPE_TAB_REC_T const pEntry = &pScopeTable->aScopeRecords[uTryLevel]; + PFN_EH4_XCPT_FILTER_T const pfnFilter = pEntry->pfnFilter; + if (pfnFilter) + { + /* Call the __except filtering expression: */ + //RTAssertMsg2("_except_handler4: Calling pfnFilter=%p\n", pfnFilter); + EXCEPTION_POINTERS XcptPtrs = { pXcptRec, pCpuCtx }; + pEh4XcptRegRec->pXctpPtrs = &XcptPtrs; + LONG lRet = rtVccEh4DoFiltering(pfnFilter, pbFrame); + pEh4XcptRegRec->pXctpPtrs = NULL; + //RTAssertMsg2("_except_handler4: pfnFilter=%p -> %ld\n", pfnFilter, lRet); + rtVccEh4ValidateCookies(pScopeTable, pbFrame); + + /* Return if we're supposed to continue execution (the convention + it to match negative values rather than the exact defined value): */ + AssertCompile(EXCEPTION_CONTINUE_EXECUTION == -1); + if (lRet <= EXCEPTION_CONTINUE_EXECUTION) + return ExceptionContinueExecution; + + /* Similarly, the handler is executed for any positive value. */ + AssertCompile(EXCEPTION_CONTINUE_SEARCH == 0); + AssertCompile(EXCEPTION_EXECUTE_HANDLER == 1); + if (lRet >= EXCEPTION_EXECUTE_HANDLER) + { + /* We're about to resume execution in the __except block, so unwind + up to it first. */ + //RTAssertMsg2("_except_handler4: global unwind\n"); + rtVccEh4DoGlobalUnwind(pXcptRec, &pEh4XcptRegRec->XcptRec); + if (pEh4XcptRegRec->uTryLevel != EH4_TOPMOST_TRY_LEVEL) + { + //RTAssertMsg2("_except_handler4: local unwind\n"); + rtVccEh4DoLocalUnwind(pEh4XcptRegRec, uTryLevel, pbFrame); + } + rtVccEh4ValidateCookies(pScopeTable, pbFrame); + + /* Now jump to the __except block. This will _not_ return. */ + //RTAssertMsg2("_except_handler4: jumping to __except block %p (level %#x)\n", pEntry->pfnHandler, pEntry->uEnclosingLevel); + pEh4XcptRegRec->uTryLevel = pEntry->uEnclosingLevel; + rtVccEh4ValidateCookies(pScopeTable, pbFrame); /* paranoia^2 */ + + rtVccEh4JumpToHandler(pEntry->pfnHandler, pbFrame); + /* (not reached) */ + } + } + + /* + * Next try level. + */ + uTryLevel = pEntry->uEnclosingLevel; + } + } + /* + * If not dispatching we're unwinding, so we call any __finally blocks. + */ + else + { + //RTAssertMsg2("_except_handler4: unwind: uTryLevel=%#x\n", pEh4XcptRegRec->uTryLevel); + if (pEh4XcptRegRec->uTryLevel != EH4_TOPMOST_TRY_LEVEL) + { + rtVccEh4DoLocalUnwind(pEh4XcptRegRec, EH4_TOPMOST_TRY_LEVEL, pbFrame); + rtVccEh4ValidateCookies(pScopeTable, pbFrame); + } + } + + RT_NOREF(pvCtx); + return ExceptionContinueSearch; +} + |