/* $Id: SUPR3HardenedVerify.cpp 69500 2017-10-28 15:14:05Z vboxsync $ */ /** @file * VirtualBox Support Library - Verification of Hardened Installation. */ /* * Copyright (C) 2006-2017 Oracle Corporation * * This file is part of VirtualBox Open Source Edition (OSE), as * available from http://www.virtualbox.org. This file is free software; * you can redistribute it and/or modify it under the terms of the GNU * General Public License (GPL) as published by the Free Software * Foundation, in version 2 as it comes in the "COPYING" file of the * VirtualBox OSE distribution. VirtualBox OSE is distributed in the * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind. * * The contents of this file may alternatively be used under the terms * of the Common Development and Distribution License Version 1.0 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the * VirtualBox OSE 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. */ /********************************************************************************************************************************* * Header Files * *********************************************************************************************************************************/ #if defined(RT_OS_OS2) # define INCL_BASE # define INCL_ERRORS # include # include # include # include # include # include # include #elif defined(RT_OS_WINDOWS) # include # ifndef IN_SUP_HARDENED_R3 # include # endif #else /* UNIXes */ # include # include # include # include # include # include # include # include # include # include # include # include # include # ifdef RT_OS_DARWIN # include # endif #endif #include #include #include #include #include #include #include #include "SUPLibInternal.h" #if defined(RT_OS_WINDOWS) && defined(VBOX_WITH_HARDENING) # define SUPHNTVI_NO_NT_STUFF # include "win/SUPHardenedVerify-win.h" #endif /********************************************************************************************************************************* * Defined Constants And Macros * *********************************************************************************************************************************/ /** The max path length acceptable for a trusted path. */ #define SUPR3HARDENED_MAX_PATH 260U /** Enable to resolve symlinks using realpath() instead of cooking our own stuff. */ #define SUP_HARDENED_VERIFY_FOLLOW_SYMLINKS_USE_REALPATH 1 #ifdef RT_OS_SOLARIS # define dirfd(d) ((d)->d_fd) #endif /** Compare table file names with externally supplied names. */ #if defined(RT_OS_WINDOWS) || defined(RT_OS_OS2) # define SUP_COMP_FILENAME RTStrICmp #else # define SUP_COMP_FILENAME suplibHardenedStrCmp #endif /********************************************************************************************************************************* * Global Variables * *********************************************************************************************************************************/ /** * The files that gets verified. * * @todo This needs reviewing against the linux packages. * @todo The excessive use of kSupID_AppSharedLib needs to be reviewed at some point. For * the time being we're building the linux packages with SharedLib pointing to * AppPrivArch (lazy bird). * * @remarks If you add executables here, you might need to update * g_apszSupNtVpAllowedVmExes in SUPHardenedVerifyProcess-win.cpp. */ static SUPINSTFILE const g_aSupInstallFiles[] = { /* type, dir, fOpt, "pszFile" */ /* ---------------------------------------------------------------------- */ { kSupIFT_Dll, kSupID_AppPrivArch, false, "VMMR0.r0" }, { kSupIFT_Dll, kSupID_AppPrivArch, false, "VBoxDDR0.r0" }, { kSupIFT_Dll, kSupID_AppPrivArch, false, "VBoxDD2R0.r0" }, #ifdef VBOX_WITH_RAW_MODE { kSupIFT_Rc, kSupID_AppPrivArch, false, "VMMRC.rc" }, { kSupIFT_Rc, kSupID_AppPrivArch, false, "VBoxDDRC.rc" }, { kSupIFT_Rc, kSupID_AppPrivArch, false, "VBoxDD2RC.rc" }, #endif { kSupIFT_Dll, kSupID_AppSharedLib, false, "VBoxRT" SUPLIB_DLL_SUFF }, { kSupIFT_Dll, kSupID_AppSharedLib, false, "VBoxVMM" SUPLIB_DLL_SUFF }, #ifdef VBOX_WITH_REM { kSupIFT_Dll, kSupID_AppSharedLib, false, "VBoxREM" SUPLIB_DLL_SUFF }, #endif #if HC_ARCH_BITS == 32 { kSupIFT_Dll, kSupID_AppSharedLib, true, "VBoxREM32" SUPLIB_DLL_SUFF }, { kSupIFT_Dll, kSupID_AppSharedLib, true, "VBoxREM64" SUPLIB_DLL_SUFF }, #endif { kSupIFT_Dll, kSupID_AppSharedLib, false, "VBoxDD" SUPLIB_DLL_SUFF }, { kSupIFT_Dll, kSupID_AppSharedLib, false, "VBoxDD2" SUPLIB_DLL_SUFF }, { kSupIFT_Dll, kSupID_AppSharedLib, false, "VBoxDDU" SUPLIB_DLL_SUFF }, { kSupIFT_Exe, kSupID_AppBin, true, "VBoxVMMPreload" SUPLIB_EXE_SUFF }, { kSupIFT_Dll, kSupID_AppPrivArch, true, "VBoxVMMPreload" SUPLIB_DLL_SUFF }, //#ifdef VBOX_WITH_DEBUGGER_GUI { kSupIFT_Dll, kSupID_AppSharedLib, true, "VBoxDbg" SUPLIB_DLL_SUFF }, { kSupIFT_Dll, kSupID_AppSharedLib, true, "VBoxDbg3" SUPLIB_DLL_SUFF }, //#endif //#ifdef VBOX_WITH_SHARED_CLIPBOARD { kSupIFT_Dll, kSupID_AppPrivArch, true, "VBoxSharedClipboard" SUPLIB_DLL_SUFF }, //#endif //#ifdef VBOX_WITH_SHARED_FOLDERS { kSupIFT_Dll, kSupID_AppPrivArch, true, "VBoxSharedFolders" SUPLIB_DLL_SUFF }, //#endif //#ifdef VBOX_WITH_DRAG_AND_DROP { kSupIFT_Dll, kSupID_AppPrivArch, true, "VBoxDragAndDropSvc" SUPLIB_DLL_SUFF }, //#endif //#ifdef VBOX_WITH_GUEST_PROPS { kSupIFT_Dll, kSupID_AppPrivArch, true, "VBoxGuestPropSvc" SUPLIB_DLL_SUFF }, //#endif //#ifdef VBOX_WITH_GUEST_CONTROL { kSupIFT_Dll, kSupID_AppPrivArch, true, "VBoxGuestControlSvc" SUPLIB_DLL_SUFF }, //#endif { kSupIFT_Dll, kSupID_AppPrivArch, true, "VBoxHostChannel" SUPLIB_DLL_SUFF }, { kSupIFT_Dll, kSupID_AppPrivArch, true, "VBoxSharedCrOpenGL" SUPLIB_DLL_SUFF }, { kSupIFT_Dll, kSupID_AppPrivArch, true, "VBoxOGLhostcrutil" SUPLIB_DLL_SUFF }, { kSupIFT_Dll, kSupID_AppPrivArch, true, "VBoxOGLhosterrorspu" SUPLIB_DLL_SUFF }, { kSupIFT_Dll, kSupID_AppPrivArch, true, "VBoxOGLrenderspu" SUPLIB_DLL_SUFF }, { kSupIFT_Exe, kSupID_AppBin, true, "VBoxManage" SUPLIB_EXE_SUFF }, #ifdef VBOX_WITH_MAIN { kSupIFT_Exe, kSupID_AppBin, false, "VBoxSVC" SUPLIB_EXE_SUFF }, #ifdef RT_OS_WINDOWS { kSupIFT_Dll, kSupID_AppSharedLib, false, "VBoxC" SUPLIB_DLL_SUFF }, #else { kSupIFT_Exe, kSupID_AppPrivArch, false, "VBoxXPCOMIPCD" SUPLIB_EXE_SUFF }, { kSupIFT_Dll, kSupID_AppSharedLib, false, "VBoxXPCOM" SUPLIB_DLL_SUFF }, { kSupIFT_Dll, kSupID_AppPrivArchComp, false, "VBoxXPCOMIPCC" SUPLIB_DLL_SUFF }, { kSupIFT_Dll, kSupID_AppPrivArchComp, false, "VBoxC" SUPLIB_DLL_SUFF }, { kSupIFT_Dll, kSupID_AppPrivArchComp, false, "VBoxSVCM" SUPLIB_DLL_SUFF }, { kSupIFT_Data, kSupID_AppPrivArchComp, false, "VBoxXPCOMBase.xpt" }, #endif #endif { kSupIFT_Dll, kSupID_AppSharedLib, true, "VRDPAuth" SUPLIB_DLL_SUFF }, { kSupIFT_Dll, kSupID_AppSharedLib, true, "VBoxAuth" SUPLIB_DLL_SUFF }, { kSupIFT_Dll, kSupID_AppSharedLib, true, "VBoxVRDP" SUPLIB_DLL_SUFF }, //#ifdef VBOX_WITH_HEADLESS { kSupIFT_Exe, kSupID_AppBin, true, "VBoxHeadless" SUPLIB_EXE_SUFF }, { kSupIFT_Dll, kSupID_AppPrivArch, true, "VBoxHeadless" SUPLIB_DLL_SUFF }, { kSupIFT_Dll, kSupID_AppPrivArch, true, "VBoxVideoRecFB" SUPLIB_DLL_SUFF }, //#endif //#ifdef VBOX_WITH_QTGUI { kSupIFT_Exe, kSupID_AppBin, true, "VirtualBox" SUPLIB_EXE_SUFF }, { kSupIFT_Dll, kSupID_AppPrivArch, true, "VirtualBox" SUPLIB_DLL_SUFF }, # ifdef RT_OS_DARWIN { kSupIFT_Exe, kSupID_AppBin, true, "VirtualBoxVM" SUPLIB_EXE_SUFF }, # endif # if !defined(RT_OS_DARWIN) && !defined(RT_OS_WINDOWS) && !defined(RT_OS_OS2) { kSupIFT_Dll, kSupID_AppSharedLib, true, "VBoxKeyboard" SUPLIB_DLL_SUFF }, # endif //#endif //#ifdef VBOX_WITH_VBOXSDL { kSupIFT_Exe, kSupID_AppBin, true, "VBoxSDL" SUPLIB_EXE_SUFF }, { kSupIFT_Dll, kSupID_AppPrivArch, true, "VBoxSDL" SUPLIB_DLL_SUFF }, //#endif //#ifdef VBOX_WITH_WEBSERVICES { kSupIFT_Exe, kSupID_AppBin, true, "vboxwebsrv" SUPLIB_EXE_SUFF }, //#endif #ifdef RT_OS_LINUX { kSupIFT_Exe, kSupID_AppBin, true, "VBoxTunctl" SUPLIB_EXE_SUFF }, #endif //#ifdef VBOX_WITH_NETFLT { kSupIFT_Exe, kSupID_AppBin, true, "VBoxNetDHCP" SUPLIB_EXE_SUFF }, { kSupIFT_Dll, kSupID_AppPrivArch, true, "VBoxNetDHCP" SUPLIB_DLL_SUFF }, //#endif //#ifdef VBOX_WITH_LWIP_NAT { kSupIFT_Exe, kSupID_AppBin, true, "VBoxNetNAT" SUPLIB_EXE_SUFF }, { kSupIFT_Dll, kSupID_AppPrivArch, true, "VBoxNetNAT" SUPLIB_DLL_SUFF }, //#endif #if defined(VBOX_WITH_HARDENING) && defined(RT_OS_WINDOWS) # define HARDENED_TESTCASE_BIN_ENTRY(a_szName) \ { kSupIFT_TestExe, kSupID_AppBin, true, a_szName SUPLIB_EXE_SUFF }, \ { kSupIFT_TestDll, kSupID_AppBin, true, a_szName SUPLIB_DLL_SUFF } HARDENED_TESTCASE_BIN_ENTRY("tstMicro"), HARDENED_TESTCASE_BIN_ENTRY("tstPDMAsyncCompletion"), HARDENED_TESTCASE_BIN_ENTRY("tstPDMAsyncCompletionStress"), HARDENED_TESTCASE_BIN_ENTRY("tstVMM"), HARDENED_TESTCASE_BIN_ENTRY("tstVMREQ"), # define HARDENED_TESTCASE_ENTRY(a_szName) \ { kSupIFT_TestExe, kSupID_Testcase, true, a_szName SUPLIB_EXE_SUFF }, \ { kSupIFT_TestDll, kSupID_Testcase, true, a_szName SUPLIB_DLL_SUFF } HARDENED_TESTCASE_ENTRY("tstCFGM"), HARDENED_TESTCASE_ENTRY("tstGIP-2"), HARDENED_TESTCASE_ENTRY("tstIntNet-1"), HARDENED_TESTCASE_ENTRY("tstMMHyperHeap"), HARDENED_TESTCASE_ENTRY("tstRTR0ThreadPreemptionDriver"), HARDENED_TESTCASE_ENTRY("tstRTR0MemUserKernelDriver"), HARDENED_TESTCASE_ENTRY("tstRTR0SemMutexDriver"), HARDENED_TESTCASE_ENTRY("tstRTR0TimerDriver"), HARDENED_TESTCASE_ENTRY("tstSSM"), #endif }; /** Array parallel to g_aSupInstallFiles containing per-file status info. */ static SUPVERIFIEDFILE g_aSupVerifiedFiles[RT_ELEMENTS(g_aSupInstallFiles)]; /** Array index by install directory specifier containing info about verified directories. */ static SUPVERIFIEDDIR g_aSupVerifiedDirs[kSupID_End]; /** * Assembles the path to a directory. * * @returns VINF_SUCCESS on success, some error code on failure (fFatal * decides whether it returns or not). * * @param enmDir The directory. * @param pszDst Where to assemble the path. * @param cchDst The size of the buffer. * @param fFatal Whether failures should be treated as fatal (true) or not (false). */ static int supR3HardenedMakePath(SUPINSTDIR enmDir, char *pszDst, size_t cchDst, bool fFatal) { int rc; switch (enmDir) { case kSupID_AppBin: rc = supR3HardenedPathAppBin(pszDst, cchDst); break; case kSupID_AppSharedLib: rc = supR3HardenedPathAppSharedLibs(pszDst, cchDst); break; case kSupID_AppPrivArch: rc = supR3HardenedPathAppPrivateArch(pszDst, cchDst); break; case kSupID_AppPrivArchComp: rc = supR3HardenedPathAppPrivateArch(pszDst, cchDst); if (RT_SUCCESS(rc)) { size_t off = suplibHardenedStrLen(pszDst); if (cchDst - off >= sizeof("/components")) suplibHardenedMemCopy(&pszDst[off], "/components", sizeof("/components")); else rc = VERR_BUFFER_OVERFLOW; } break; case kSupID_AppPrivNoArch: rc = supR3HardenedPathAppPrivateNoArch(pszDst, cchDst); break; case kSupID_Testcase: rc = supR3HardenedPathAppBin(pszDst, cchDst); if (RT_SUCCESS(rc)) { size_t off = suplibHardenedStrLen(pszDst); if (cchDst - off >= sizeof("/testcase")) suplibHardenedMemCopy(&pszDst[off], "/testcase", sizeof("/testcase")); else rc = VERR_BUFFER_OVERFLOW; } break; default: return supR3HardenedError(VERR_INTERNAL_ERROR, fFatal, "supR3HardenedMakePath: enmDir=%d\n", enmDir); } if (RT_FAILURE(rc)) supR3HardenedError(rc, fFatal, "supR3HardenedMakePath: enmDir=%d rc=%d\n", enmDir, rc); return rc; } /** * Assembles the path to a file table entry, with or without the actual filename. * * @returns VINF_SUCCESS on success, some error code on failure (fFatal * decides whether it returns or not). * * @param pFile The file table entry. * @param pszDst Where to assemble the path. * @param cchDst The size of the buffer. * @param fWithFilename If set, the filename is included, otherwise it is omitted (no trailing slash). * @param fFatal Whether failures should be treated as fatal (true) or not (false). */ static int supR3HardenedMakeFilePath(PCSUPINSTFILE pFile, char *pszDst, size_t cchDst, bool fWithFilename, bool fFatal) { /* * Combine supR3HardenedMakePath and the filename. */ int rc = supR3HardenedMakePath(pFile->enmDir, pszDst, cchDst, fFatal); if (RT_SUCCESS(rc) && fWithFilename) { size_t cchFile = suplibHardenedStrLen(pFile->pszFile); size_t off = suplibHardenedStrLen(pszDst); if (cchDst - off >= cchFile + 2) { pszDst[off++] = '/'; suplibHardenedMemCopy(&pszDst[off], pFile->pszFile, cchFile + 1); } else rc = supR3HardenedError(VERR_BUFFER_OVERFLOW, fFatal, "supR3HardenedMakeFilePath: pszFile=%s off=%lu\n", pFile->pszFile, (long)off); } return rc; } /** * Verifies a directory. * * @returns VINF_SUCCESS on success. On failure, an error code is returned if * fFatal is clear and if it's set the function wont return. * @param enmDir The directory specifier. * @param fFatal Whether validation failures should be treated as * fatal (true) or not (false). */ DECLHIDDEN(int) supR3HardenedVerifyFixedDir(SUPINSTDIR enmDir, bool fFatal) { /* * Validate the index just to be on the safe side... */ if (enmDir <= kSupID_Invalid || enmDir >= kSupID_End) return supR3HardenedError(VERR_INTERNAL_ERROR, fFatal, "supR3HardenedVerifyDir: enmDir=%d\n", enmDir); /* * Already validated? */ if (g_aSupVerifiedDirs[enmDir].fValidated) return VINF_SUCCESS; /** @todo revalidate? */ /* initialize the entry. */ if (g_aSupVerifiedDirs[enmDir].hDir != 0) supR3HardenedError(VERR_INTERNAL_ERROR, fFatal, "supR3HardenedVerifyDir: hDir=%p enmDir=%d\n", (void *)g_aSupVerifiedDirs[enmDir].hDir, enmDir); g_aSupVerifiedDirs[enmDir].hDir = -1; g_aSupVerifiedDirs[enmDir].fValidated = false; /* * Make the path and open the directory. */ char szPath[RTPATH_MAX]; int rc = supR3HardenedMakePath(enmDir, szPath, sizeof(szPath), fFatal); if (RT_SUCCESS(rc)) { #if defined(RT_OS_WINDOWS) PRTUTF16 pwszPath; rc = RTStrToUtf16(szPath, &pwszPath); if (RT_SUCCESS(rc)) { HANDLE hDir = CreateFileW(pwszPath, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_DELETE | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_BACKUP_SEMANTICS, NULL); if (hDir != INVALID_HANDLE_VALUE) { /** @todo check the type */ /* That's all on windows, for now at least... */ g_aSupVerifiedDirs[enmDir].hDir = (intptr_t)hDir; g_aSupVerifiedDirs[enmDir].fValidated = true; } else if (enmDir == kSupID_Testcase) { g_aSupVerifiedDirs[enmDir].fValidated = true; rc = VINF_SUCCESS; /* Optional directory, ignore if missing. */ } else { int err = RtlGetLastWin32Error(); rc = supR3HardenedError(VERR_PATH_NOT_FOUND, fFatal, "supR3HardenedVerifyDir: Failed to open \"%s\": err=%d\n", szPath, err); } RTUtf16Free(pwszPath); } else rc = supR3HardenedError(rc, fFatal, "supR3HardenedVerifyDir: Failed to convert \"%s\" to UTF-16: err=%d\n", szPath, rc); #else /* UNIXY */ int fd = open(szPath, O_RDONLY, 0); if (fd >= 0) { /* * On unixy systems we'll make sure the directory is owned by root * and not writable by the group and user. */ struct stat st; if (!fstat(fd, &st)) { if ( st.st_uid == 0 && !(st.st_mode & (S_IWGRP | S_IWOTH)) && S_ISDIR(st.st_mode)) { g_aSupVerifiedDirs[enmDir].hDir = fd; g_aSupVerifiedDirs[enmDir].fValidated = true; } else { if (!S_ISDIR(st.st_mode)) rc = supR3HardenedError(VERR_NOT_A_DIRECTORY, fFatal, "supR3HardenedVerifyDir: \"%s\" is not a directory\n", szPath, (long)st.st_uid); else if (st.st_uid) rc = supR3HardenedError(VERR_ACCESS_DENIED, fFatal, "supR3HardenedVerifyDir: Cannot trust the directory \"%s\": not owned by root (st_uid=%ld)\n", szPath, (long)st.st_uid); else rc = supR3HardenedError(VERR_ACCESS_DENIED, fFatal, "supR3HardenedVerifyDir: Cannot trust the directory \"%s\": group and/or other writable (st_mode=0%lo)\n", szPath, (long)st.st_mode); close(fd); } } else { int err = errno; rc = supR3HardenedError(VERR_ACCESS_DENIED, fFatal, "supR3HardenedVerifyDir: Failed to fstat \"%s\": %s (%d)\n", szPath, strerror(err), err); close(fd); } } else if (enmDir == kSupID_Testcase) { g_aSupVerifiedDirs[enmDir].fValidated = true; rc = VINF_SUCCESS; /* Optional directory, ignore if missing. */ } else { int err = errno; rc = supR3HardenedError(VERR_PATH_NOT_FOUND, fFatal, "supR3HardenedVerifyDir: Failed to open \"%s\": %s (%d)\n", szPath, strerror(err), err); } #endif /* UNIXY */ } return rc; } #ifdef RT_OS_WINDOWS /** * Opens the file for verification. * * @returns VINF_SUCCESS on success. On failure, an error code is returned if * fFatal is clear and if it's set the function wont return. * @param pFile The file entry. * @param fFatal Whether validation failures should be treated as * kl fatal (true) or not (false). * @param phFile The file handle, set to -1 if we failed to open * the file. The function may return VINF_SUCCESS * and a -1 handle if the file is optional. */ static int supR3HardenedVerifyFileOpen(PCSUPINSTFILE pFile, bool fFatal, intptr_t *phFile) { *phFile = -1; char szPath[RTPATH_MAX]; int rc = supR3HardenedMakeFilePath(pFile, szPath, sizeof(szPath), true /*fWithFilename*/, fFatal); if (RT_SUCCESS(rc)) { PRTUTF16 pwszPath; rc = RTStrToUtf16(szPath, &pwszPath); if (RT_SUCCESS(rc)) { HANDLE hFile = CreateFileW(pwszPath, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL); if (hFile != INVALID_HANDLE_VALUE) { *phFile = (intptr_t)hFile; rc = VINF_SUCCESS; } else { int err = RtlGetLastWin32Error(); if ( !pFile->fOptional || ( err != ERROR_FILE_NOT_FOUND && (err != ERROR_PATH_NOT_FOUND || pFile->enmDir != kSupID_Testcase) ) ) rc = supR3HardenedError(VERR_PATH_NOT_FOUND, fFatal, "supR3HardenedVerifyFileInternal: Failed to open '%s': err=%d\n", szPath, err); } RTUtf16Free(pwszPath); } else rc = supR3HardenedError(rc, fFatal, "supR3HardenedVerifyFileInternal: Failed to convert '%s' to UTF-16: %Rrc\n", szPath, rc); } return rc; } /** * Worker for supR3HardenedVerifyFileInternal. * * @returns VINF_SUCCESS on success. On failure, an error code is returned if * fFatal is clear and if it's set the function wont return. * @param pFile The file entry. * @param pVerified The verification record. * @param fFatal Whether validation failures should be treated as * fatal (true) or not (false). * @param fLeaveFileOpen Whether the file should be left open. */ static int supR3HardenedVerifyFileSignature(PCSUPINSTFILE pFile, PSUPVERIFIEDFILE pVerified, bool fFatal, bool fLeaveFileOpen) { # if defined(VBOX_WITH_HARDENING) && !defined(IN_SUP_R3_STATIC) /* Latter: Not in VBoxCpuReport and friends. */ /* * Open the file if we have to. */ int rc; intptr_t hFileOpened; intptr_t hFile = pVerified->hFile; if (hFile != -1) hFileOpened = -1; else { rc = supR3HardenedVerifyFileOpen(pFile, fFatal, &hFileOpened); if (RT_FAILURE(rc)) return rc; hFile = hFileOpened; } /* * Verify the signature. */ char szErr[1024]; RTERRINFO ErrInfo; RTErrInfoInit(&ErrInfo, szErr, sizeof(szErr)); uint32_t fFlags = SUPHNTVI_F_REQUIRE_BUILD_CERT; if (pFile->enmType == kSupIFT_Rc) fFlags |= SUPHNTVI_F_RC_IMAGE; rc = supHardenedWinVerifyImageByHandleNoName((HANDLE)hFile, fFlags, &ErrInfo); if (RT_SUCCESS(rc)) pVerified->fCheckedSignature = true; else { pVerified->fCheckedSignature = false; rc = supR3HardenedError(rc, fFatal, "supR3HardenedVerifyFileInternal: '%s': Image verify error rc=%Rrc: %s\n", pFile->pszFile, rc, szErr); } /* * Close the handle if we opened the file and we should close it. */ if (hFileOpened != -1) { if (fLeaveFileOpen && RT_SUCCESS(rc)) pVerified->hFile = hFileOpened; else NtClose((HANDLE)hFileOpened); } return rc; # else /* Not checking signatures. */ RT_NOREF4(pFile, pVerified, fFatal, fLeaveFileOpen); return VINF_SUCCESS; # endif /* Not checking signatures. */ } #endif /** * Verifies a file entry. * * @returns VINF_SUCCESS on success. On failure, an error code is returned if * fFatal is clear and if it's set the function wont return. * * @param iFile The file table index of the file to be verified. * @param fFatal Whether validation failures should be treated as * fatal (true) or not (false). * @param fLeaveFileOpen Whether the file should be left open. * @param fVerifyAll Set if this is an verify all call and we will * postpone signature checking. */ static int supR3HardenedVerifyFileInternal(int iFile, bool fFatal, bool fLeaveFileOpen, bool fVerifyAll) { #ifndef RT_OS_WINDOWS RT_NOREF1(fVerifyAll); #endif PCSUPINSTFILE pFile = &g_aSupInstallFiles[iFile]; PSUPVERIFIEDFILE pVerified = &g_aSupVerifiedFiles[iFile]; /* * Already done validation? Do signature validation if we haven't yet. */ if (pVerified->fValidated) { /** @todo revalidate? Check that the file hasn't been replace or similar. */ #ifdef RT_OS_WINDOWS if (!pVerified->fCheckedSignature && !fVerifyAll) return supR3HardenedVerifyFileSignature(pFile, pVerified, fFatal, fLeaveFileOpen); #endif return VINF_SUCCESS; } /* initialize the entry. */ if (pVerified->hFile != 0) supR3HardenedError(VERR_INTERNAL_ERROR, fFatal, "supR3HardenedVerifyFileInternal: hFile=%p (%s)\n", (void *)pVerified->hFile, pFile->pszFile); pVerified->hFile = -1; pVerified->fValidated = false; #ifdef RT_OS_WINDOWS pVerified->fCheckedSignature = false; #endif /* * Verify the directory then proceed to open it. * (This'll make sure the directory is opened and that we can (later) * use openat if we wish.) */ int rc = supR3HardenedVerifyFixedDir(pFile->enmDir, fFatal); if (RT_SUCCESS(rc)) { #if defined(RT_OS_WINDOWS) rc = supR3HardenedVerifyFileOpen(pFile, fFatal, &pVerified->hFile); if (RT_SUCCESS(rc)) { if (!fVerifyAll) rc = supR3HardenedVerifyFileSignature(pFile, pVerified, fFatal, fLeaveFileOpen); if (RT_SUCCESS(rc)) { pVerified->fValidated = true; if (!fLeaveFileOpen) { NtClose((HANDLE)pVerified->hFile); pVerified->hFile = -1; } } } #else /* !RT_OS_WINDOWS */ char szPath[RTPATH_MAX]; rc = supR3HardenedMakeFilePath(pFile, szPath, sizeof(szPath), true /*fWithFilename*/, fFatal); if (RT_SUCCESS(rc)) { int fd = open(szPath, O_RDONLY, 0); if (fd >= 0) { /* * On unixy systems we'll make sure the file is owned by root * and not writable by the group and user. */ struct stat st; if (!fstat(fd, &st)) { if ( st.st_uid == 0 && !(st.st_mode & (S_IWGRP | S_IWOTH)) && S_ISREG(st.st_mode)) { /* it's valid. */ if (fLeaveFileOpen) pVerified->hFile = fd; else close(fd); pVerified->fValidated = true; } else { if (!S_ISREG(st.st_mode)) rc = supR3HardenedError(VERR_IS_A_DIRECTORY, fFatal, "supR3HardenedVerifyFileInternal: \"%s\" is not a regular file\n", szPath, (long)st.st_uid); else if (st.st_uid) rc = supR3HardenedError(VERR_ACCESS_DENIED, fFatal, "supR3HardenedVerifyFileInternal: Cannot trust the file \"%s\": not owned by root (st_uid=%ld)\n", szPath, (long)st.st_uid); else rc = supR3HardenedError(VERR_ACCESS_DENIED, fFatal, "supR3HardenedVerifyFileInternal: Cannot trust the file \"%s\": group and/or other writable (st_mode=0%lo)\n", szPath, (long)st.st_mode); close(fd); } } else { int err = errno; rc = supR3HardenedError(VERR_ACCESS_DENIED, fFatal, "supR3HardenedVerifyFileInternal: Failed to fstat \"%s\": %s (%d)\n", szPath, strerror(err), err); close(fd); } } else { int err = errno; if (!pFile->fOptional || err != ENOENT) rc = supR3HardenedError(VERR_PATH_NOT_FOUND, fFatal, "supR3HardenedVerifyFileInternal: Failed to open \"%s\": %s (%d)\n", szPath, strerror(err), err); } } #endif /* !RT_OS_WINDOWS */ } return rc; } /** * Verifies that the specified table entry matches the given filename. * * @returns VINF_SUCCESS if matching. On mismatch fFatal indicates whether an * error is returned or we terminate the application. * * @param iFile The file table index. * @param pszFilename The filename. * @param fFatal Whether validation failures should be treated as * fatal (true) or not (false). */ static int supR3HardenedVerifySameFile(int iFile, const char *pszFilename, bool fFatal) { PCSUPINSTFILE pFile = &g_aSupInstallFiles[iFile]; /* * Construct the full path for the file table entry * and compare it with the specified file. */ char szName[RTPATH_MAX]; int rc = supR3HardenedMakeFilePath(pFile, szName, sizeof(szName), true /*fWithFilename*/, fFatal); if (RT_FAILURE(rc)) return rc; if (SUP_COMP_FILENAME(szName, pszFilename)) { /* * Normalize the two paths and compare again. */ rc = VERR_NOT_SAME_DEVICE; #if defined(RT_OS_WINDOWS) LPSTR pszIgnored; char szName2[RTPATH_MAX]; /** @todo Must use UTF-16 here! Code is mixing UTF-8 and native. */ if ( GetFullPathName(szName, RT_ELEMENTS(szName2), &szName2[0], &pszIgnored) && GetFullPathName(pszFilename, RT_ELEMENTS(szName), &szName[0], &pszIgnored)) if (!SUP_COMP_FILENAME(szName2, szName)) rc = VINF_SUCCESS; #else AssertCompile(RTPATH_MAX >= PATH_MAX); char szName2[RTPATH_MAX]; if ( realpath(szName, szName2) != NULL && realpath(pszFilename, szName) != NULL) if (!SUP_COMP_FILENAME(szName2, szName)) rc = VINF_SUCCESS; #endif if (RT_FAILURE(rc)) { supR3HardenedMakeFilePath(pFile, szName, sizeof(szName), true /*fWithFilename*/, fFatal); return supR3HardenedError(rc, fFatal, "supR3HardenedVerifySameFile: \"%s\" isn't the same as \"%s\"\n", pszFilename, szName); } } /* * Check more stuff like the stat info if it's an already open file? */ return VINF_SUCCESS; } /** * Verifies a file. * * @returns VINF_SUCCESS on success. * VERR_NOT_FOUND if the file isn't in the table, this isn't ever a fatal error. * On verification failure, an error code will be returned when fFatal is clear, * otherwise the program will be terminated. * * @param pszFilename The filename. * @param fFatal Whether validation failures should be treated as * fatal (true) or not (false). */ DECLHIDDEN(int) supR3HardenedVerifyFixedFile(const char *pszFilename, bool fFatal) { /* * Lookup the file and check if it's the same file. */ const char *pszName = supR3HardenedPathFilename(pszFilename); for (unsigned iFile = 0; iFile < RT_ELEMENTS(g_aSupInstallFiles); iFile++) if (!SUP_COMP_FILENAME(pszName, g_aSupInstallFiles[iFile].pszFile)) { int rc = supR3HardenedVerifySameFile(iFile, pszFilename, fFatal); if (RT_SUCCESS(rc)) rc = supR3HardenedVerifyFileInternal(iFile, fFatal, false /* fLeaveFileOpen */, false /* fVerifyAll */); return rc; } return VERR_NOT_FOUND; } /** * Verifies a program, worker for supR3HardenedVerifyAll. * * @returns See supR3HardenedVerifyAll. * @param pszProgName See supR3HardenedVerifyAll. * @param pszExePath The path to the executable. * @param fFatal See supR3HardenedVerifyAll. * @param fLeaveOpen The leave open setting used by * supR3HardenedVerifyAll. * @param fMainFlags Flags supplied to SUPR3HardenedMain. */ static int supR3HardenedVerifyProgram(const char *pszProgName, const char *pszExePath, bool fFatal, bool fLeaveOpen, uint32_t fMainFlags) { /* * Search the table looking for the executable and the DLL/DYLIB/SO. * Note! On darwin we have a hack in place for VirtualBoxVM helper app * to share VirtualBox.dylib with the VirtualBox app. This ASSUMES * that cchProgNameDll is equal or shorter to the exe name. */ int rc = VINF_SUCCESS; bool fExe = false; bool fDll = false; size_t const cchProgNameExe = suplibHardenedStrLen(pszProgName); #ifndef RT_OS_DARWIN size_t const cchProgNameDll = cchProgNameExe; NOREF(fMainFlags); #else size_t const cchProgNameDll = fMainFlags & SUPSECMAIN_FLAGS_OSX_VM_APP ? sizeof("VirtualBox") - 1 : cchProgNameExe; if (cchProgNameDll > cchProgNameExe) return supR3HardenedError(VERR_INTERNAL_ERROR, fFatal, "supR3HardenedVerifyProgram: SUPSECMAIN_FLAGS_OSX_VM_APP + '%s'", pszProgName); #endif for (unsigned iFile = 0; iFile < RT_ELEMENTS(g_aSupInstallFiles); iFile++) if (!suplibHardenedStrNCmp(pszProgName, g_aSupInstallFiles[iFile].pszFile, cchProgNameDll)) { if ( ( g_aSupInstallFiles[iFile].enmType == kSupIFT_Dll || g_aSupInstallFiles[iFile].enmType == kSupIFT_TestDll) && !suplibHardenedStrCmp(&g_aSupInstallFiles[iFile].pszFile[cchProgNameDll], SUPLIB_DLL_SUFF)) { /* This only has to be found (once). */ if (fDll) rc = supR3HardenedError(VERR_INTERNAL_ERROR, fFatal, "supR3HardenedVerifyProgram: duplicate DLL entry for \"%s\"\n", pszProgName); else rc = supR3HardenedVerifyFileInternal(iFile, fFatal, fLeaveOpen, true /* fVerifyAll - check sign later, only final process need check it on load. */); fDll = true; } else if ( ( g_aSupInstallFiles[iFile].enmType == kSupIFT_Exe || g_aSupInstallFiles[iFile].enmType == kSupIFT_TestExe) && ( cchProgNameExe == cchProgNameDll || !suplibHardenedStrNCmp(pszProgName, g_aSupInstallFiles[iFile].pszFile, cchProgNameExe)) && !suplibHardenedStrCmp(&g_aSupInstallFiles[iFile].pszFile[cchProgNameExe], SUPLIB_EXE_SUFF)) { /* Here we'll have to check that the specific program is the same as the entry. */ if (fExe) rc = supR3HardenedError(VERR_INTERNAL_ERROR, fFatal, "supR3HardenedVerifyProgram: duplicate EXE entry for \"%s\"\n", pszProgName); else rc = supR3HardenedVerifyFileInternal(iFile, fFatal, fLeaveOpen, false /* fVerifyAll */); fExe = true; supR3HardenedVerifySameFile(iFile, pszExePath, fFatal); } } /* * Check the findings. */ if (RT_SUCCESS(rc)) { if (!fDll && !fExe) rc = supR3HardenedError(VERR_NOT_FOUND, fFatal, "supR3HardenedVerifyProgram: Couldn't find the program \"%s\"\n", pszProgName); else if (!fExe) rc = supR3HardenedError(VERR_NOT_FOUND, fFatal, "supR3HardenedVerifyProgram: Couldn't find the EXE entry for \"%s\"\n", pszProgName); else if (!fDll) rc = supR3HardenedError(VERR_NOT_FOUND, fFatal, "supR3HardenedVerifyProgram: Couldn't find the DLL entry for \"%s\"\n", pszProgName); } return rc; } /** * Verifies all the known files (called from SUPR3HardenedMain). * * @returns VINF_SUCCESS on success. * On verification failure, an error code will be returned when fFatal is clear, * otherwise the program will be terminated. * * @param fFatal Whether validation failures should be treated as * fatal (true) or not (false). * @param pszProgName The program name. This is used to verify that * both the executable and corresponding * DLL/DYLIB/SO are valid. * @param pszExePath The path to the executable. * @param fMainFlags Flags supplied to SUPR3HardenedMain. */ DECLHIDDEN(int) supR3HardenedVerifyAll(bool fFatal, const char *pszProgName, const char *pszExePath, uint32_t fMainFlags) { /* * On windows */ #if defined(RT_OS_WINDOWS) bool fLeaveOpen = true; #else bool fLeaveOpen = false; #endif /* * The verify all the files. */ int rc = VINF_SUCCESS; for (unsigned iFile = 0; iFile < RT_ELEMENTS(g_aSupInstallFiles); iFile++) { int rc2 = supR3HardenedVerifyFileInternal(iFile, fFatal, fLeaveOpen, true /* fVerifyAll */); if (RT_FAILURE(rc2) && RT_SUCCESS(rc)) rc = rc2; } /* * Verify the program name, that is to say, check that it's in the table * (thus verified above) and verify the signature on platforms where we * sign things. */ int rc2 = supR3HardenedVerifyProgram(pszProgName, pszExePath, fFatal, fLeaveOpen, fMainFlags); if (RT_FAILURE(rc2) && RT_SUCCESS(rc)) rc2 = rc; return rc; } /** * Copies the N messages into the error buffer and returns @a rc. * * @returns Returns @a rc * @param rc The return code. * @param pErrInfo The error info structure. * @param cMsgs The number of messages in the ellipsis. * @param ... Message parts. */ static int supR3HardenedSetErrorN(int rc, PRTERRINFO pErrInfo, unsigned cMsgs, ...) { if (pErrInfo) { size_t cbErr = pErrInfo->cbMsg; char *pszErr = pErrInfo->pszMsg; va_list va; va_start(va, cMsgs); while (cMsgs-- > 0 && cbErr > 0) { const char *pszMsg = va_arg(va, const char *); size_t cchMsg = VALID_PTR(pszMsg) ? suplibHardenedStrLen(pszMsg) : 0; if (cchMsg >= cbErr) cchMsg = cbErr - 1; suplibHardenedMemCopy(pszErr, pszMsg, cchMsg); pszErr[cchMsg] = '\0'; pszErr += cchMsg; cbErr -= cchMsg; } va_end(va); pErrInfo->rc = rc; pErrInfo->fFlags |= RTERRINFO_FLAGS_SET; } return rc; } #if defined(RT_OS_DARWIN) || defined(RT_OS_LINUX) /** * Copies the four messages into the error buffer and returns @a rc. * * @returns Returns @a rc * @param rc The return code. * @param pErrInfo The error info structure. * @param pszMsg1 The first message part. * @param pszMsg2 The second message part. * @param pszMsg3 The third message part. * @param pszMsg4 The fourth message part. */ static int supR3HardenedSetError4(int rc, PRTERRINFO pErrInfo, const char *pszMsg1, const char *pszMsg2, const char *pszMsg3, const char *pszMsg4) { return supR3HardenedSetErrorN(rc, pErrInfo, 4, pszMsg1, pszMsg2, pszMsg3, pszMsg4); } #endif /** * Copies the three messages into the error buffer and returns @a rc. * * @returns Returns @a rc * @param rc The return code. * @param pErrInfo The error info structure. * @param pszMsg1 The first message part. * @param pszMsg2 The second message part. * @param pszMsg3 The third message part. */ static int supR3HardenedSetError3(int rc, PRTERRINFO pErrInfo, const char *pszMsg1, const char *pszMsg2, const char *pszMsg3) { return supR3HardenedSetErrorN(rc, pErrInfo, 3, pszMsg1, pszMsg2, pszMsg3); } #ifdef SOME_UNUSED_FUNCTION /** * Copies the two messages into the error buffer and returns @a rc. * * @returns Returns @a rc * @param rc The return code. * @param pErrInfo The error info structure. * @param pszMsg1 The first message part. * @param pszMsg2 The second message part. */ static int supR3HardenedSetError2(int rc, PRTERRINFO pErrInfo, const char *pszMsg1, const char *pszMsg2) { return supR3HardenedSetErrorN(rc, pErrInfo, 2, pszMsg1, pszMsg2); } #endif #ifndef SUP_HARDENED_VERIFY_FOLLOW_SYMLINKS_USE_REALPATH # if defined(RT_OS_DARWIN) || defined(RT_OS_LINUX) /** * Copies the error message to the error buffer and returns @a rc. * * @returns Returns @a rc * @param rc The return code. * @param pErrInfo The error info structure. * @param pszMsg The message. */ static int supR3HardenedSetError(int rc, PRTERRINFO pErrInfo, const char *pszMsg) { return supR3HardenedSetErrorN(rc, pErrInfo, 1, pszMsg); } # endif #endif /** * Output from a successfull supR3HardenedVerifyPathSanity call. */ typedef struct SUPR3HARDENEDPATHINFO { /** The length of the path in szCopy. */ uint16_t cch; /** The number of path components. */ uint16_t cComponents; /** Set if the path ends with slash, indicating that it's a directory * reference and not a file reference. The slash has been removed from * the copy. */ bool fDirSlash; /** The offset where each path component starts, i.e. the char after the * slash. The array has cComponents + 1 entries, where the final one is * cch + 1 so that one can always terminate the current component by * szPath[aoffComponent[i] - 1] = '\0'. */ uint16_t aoffComponents[32+1]; /** A normalized copy of the path. * Reserve some extra space so we can be more relaxed about overflow * checks and terminator paddings, especially when recursing. */ char szPath[SUPR3HARDENED_MAX_PATH * 2]; } SUPR3HARDENEDPATHINFO; /** Pointer to a parsed path. */ typedef SUPR3HARDENEDPATHINFO *PSUPR3HARDENEDPATHINFO; /** * Verifies that the path is absolutely sane, it also parses the path. * * A sane path starts at the root (w/ drive letter on DOS derived systems) and * does not have any relative bits (/../) or unnecessary slashes (/bin//ls). * Sane paths are less or equal to SUPR3HARDENED_MAX_PATH bytes in length. UNC * paths are not supported. * * @returns VBox status code. * @param pszPath The path to check. * @param pErrInfo The error info structure. * @param pInfo Where to return a copy of the path along with * parsing information. */ static int supR3HardenedVerifyPathSanity(const char *pszPath, PRTERRINFO pErrInfo, PSUPR3HARDENEDPATHINFO pInfo) { const char *pszSrc = pszPath; char *pszDst = pInfo->szPath; /* * Check that it's an absolute path and copy the volume/root specifier. */ #if defined(RT_OS_WINDOWS) || defined(RT_OS_OS2) if ( !RT_C_IS_ALPHA(pszSrc[0]) || pszSrc[1] != ':' || !RTPATH_IS_SLASH(pszSrc[2])) return supR3HardenedSetError3(VERR_SUPLIB_PATH_NOT_ABSOLUTE, pErrInfo, "The path is not absolute: '", pszPath, "'"); *pszDst++ = RT_C_TO_UPPER(pszSrc[0]); *pszDst++ = ':'; *pszDst++ = RTPATH_SLASH; pszSrc += 3; #else if (!RTPATH_IS_SLASH(pszSrc[0])) return supR3HardenedSetError3(VERR_SUPLIB_PATH_NOT_ABSOLUTE, pErrInfo, "The path is not absolute: '", pszPath, "'"); *pszDst++ = RTPATH_SLASH; pszSrc += 1; #endif /* * No path specifying the root or something very shortly thereafter will * be approved of. */ if (pszSrc[0] == '\0') return supR3HardenedSetError3(VERR_SUPLIB_PATH_IS_ROOT, pErrInfo, "The path is root: '", pszPath, "'"); if ( pszSrc[1] == '\0' || pszSrc[2] == '\0') return supR3HardenedSetError3(VERR_SUPLIB_PATH_TOO_SHORT, pErrInfo, "The path is too short: '", pszPath, "'"); #if RTPATH_STYLE == RTPATH_STR_F_STYLE_UNIX /* * Skip double slashes. */ while (RTPATH_IS_SLASH(*pszSrc)) pszSrc++; #else /* * The root slash should be alone to avoid UNC confusion. */ if (RTPATH_IS_SLASH(pszSrc[0])) return supR3HardenedSetError3(VERR_SUPLIB_PATH_NOT_CLEAN, pErrInfo, "The path is not clean of leading double slashes: '", pszPath, "'"); #endif /* * Check each component. No parent references. */ pInfo->cComponents = 0; pInfo->fDirSlash = false; while (pszSrc[0]) { /* Sanity checks. */ if ( pszSrc[0] == '.' && pszSrc[1] == '.' && RTPATH_IS_SLASH(pszSrc[2])) return supR3HardenedSetError3(VERR_SUPLIB_PATH_NOT_ABSOLUTE, pErrInfo, "The path is not absolute: '", pszPath, "'"); /* Record the start of the component. */ if (pInfo->cComponents >= RT_ELEMENTS(pInfo->aoffComponents) - 1) return supR3HardenedSetError3(VERR_SUPLIB_PATH_TOO_MANY_COMPONENTS, pErrInfo, "The path has too many components: '", pszPath, "'"); pInfo->aoffComponents[pInfo->cComponents++] = pszDst - &pInfo->szPath[0]; /* Traverse to the end of the component, copying it as we go along. */ while (pszSrc[0]) { if (RTPATH_IS_SLASH(pszSrc[0])) { pszSrc++; if (*pszSrc) *pszDst++ = RTPATH_SLASH; else pInfo->fDirSlash = true; break; } *pszDst++ = *pszSrc++; if ((uintptr_t)(pszDst - &pInfo->szPath[0]) >= SUPR3HARDENED_MAX_PATH) return supR3HardenedSetError3(VERR_SUPLIB_PATH_TOO_LONG, pErrInfo, "The path is too long: '", pszPath, "'"); } /* Skip double slashes. */ while (RTPATH_IS_SLASH(*pszSrc)) pszSrc++; } /* Terminate the string and enter its length. */ pszDst[0] = '\0'; pszDst[1] = '\0'; /* for aoffComponents */ pInfo->cch = (uint16_t)(pszDst - &pInfo->szPath[0]); pInfo->aoffComponents[pInfo->cComponents] = pInfo->cch + 1; return VINF_SUCCESS; } /** * The state information collected by supR3HardenedVerifyFsObject. * * This can be used to verify that a directory we've opened for enumeration is * the same as the one that supR3HardenedVerifyFsObject just verified. It can * equally be used to verify a native specfied by the user. */ typedef struct SUPR3HARDENEDFSOBJSTATE { #ifdef RT_OS_WINDOWS /** Not implemented for windows yet. */ char chTodo; #else /** The stat output. */ struct stat Stat; #endif } SUPR3HARDENEDFSOBJSTATE; /** Pointer to a file system object state. */ typedef SUPR3HARDENEDFSOBJSTATE *PSUPR3HARDENEDFSOBJSTATE; /** Pointer to a const file system object state. */ typedef SUPR3HARDENEDFSOBJSTATE const *PCSUPR3HARDENEDFSOBJSTATE; /** * Query information about a file system object by path. * * @returns VBox status code, error buffer filled on failure. * @param pszPath The path to the object. * @param pFsObjState Where to return the state information. * @param pErrInfo The error info structure. */ static int supR3HardenedQueryFsObjectByPath(char const *pszPath, PSUPR3HARDENEDFSOBJSTATE pFsObjState, PRTERRINFO pErrInfo) { #if defined(RT_OS_WINDOWS) /** @todo Windows hardening. */ pFsObjState->chTodo = 0; RT_NOREF2(pszPath, pErrInfo); return VINF_SUCCESS; #else /* * Stat the object, do not follow links. */ if (lstat(pszPath, &pFsObjState->Stat) != 0) { /* Ignore access errors */ if (errno != EACCES) return supR3HardenedSetErrorN(VERR_SUPLIB_STAT_FAILED, pErrInfo, 5, "stat failed with ", strerror(errno), " on: '", pszPath, "'"); } /* * Read ACLs. */ /** @todo */ return VINF_SUCCESS; #endif } /** * Query information about a file system object by native handle. * * @returns VBox status code, error buffer filled on failure. * @param hNative The native handle to the object @a pszPath * specifies and this should be verified to be the * same file system object. * @param pFsObjState Where to return the state information. * @param pszPath The path to the object. (For the error message * only.) * @param pErrInfo The error info structure. */ static int supR3HardenedQueryFsObjectByHandle(RTHCUINTPTR hNative, PSUPR3HARDENEDFSOBJSTATE pFsObjState, char const *pszPath, PRTERRINFO pErrInfo) { #if defined(RT_OS_WINDOWS) /** @todo Windows hardening. */ pFsObjState->chTodo = 0; RT_NOREF3(hNative, pszPath, pErrInfo); return VINF_SUCCESS; #else /* * Stat the object, do not follow links. */ if (fstat((int)hNative, &pFsObjState->Stat) != 0) return supR3HardenedSetErrorN(VERR_SUPLIB_STAT_FAILED, pErrInfo, 5, "fstat failed with ", strerror(errno), " on '", pszPath, "'"); /* * Read ACLs. */ /** @todo */ return VINF_SUCCESS; #endif } /** * Verifies that the file system object indicated by the native handle is the * same as the one @a pFsObjState indicates. * * @returns VBox status code, error buffer filled on failure. * @param pFsObjState1 File system object information/state by path. * @param pFsObjState2 File system object information/state by handle. * @param pszPath The path to the object @a pFsObjState * describes. (For the error message.) * @param pErrInfo The error info structure. */ static int supR3HardenedIsSameFsObject(PCSUPR3HARDENEDFSOBJSTATE pFsObjState1, PCSUPR3HARDENEDFSOBJSTATE pFsObjState2, const char *pszPath, PRTERRINFO pErrInfo) { #if defined(RT_OS_WINDOWS) /** @todo Windows hardening. */ RT_NOREF4(pFsObjState1, pFsObjState2, pszPath, pErrInfo); return VINF_SUCCESS; #elif defined(RT_OS_OS2) RT_NOREF4(pFsObjState1, pFsObjState2, pszPath, pErrInfo); return VINF_SUCCESS; #else /* * Compare the ino+dev, then the uid+gid and finally the important mode * bits. Technically the first one should be enough, but we're paranoid. */ if ( pFsObjState1->Stat.st_ino != pFsObjState2->Stat.st_ino || pFsObjState1->Stat.st_dev != pFsObjState2->Stat.st_dev) return supR3HardenedSetError3(VERR_SUPLIB_NOT_SAME_OBJECT, pErrInfo, "The native handle is not the same as '", pszPath, "' (ino/dev)"); if ( pFsObjState1->Stat.st_uid != pFsObjState2->Stat.st_uid || pFsObjState1->Stat.st_gid != pFsObjState2->Stat.st_gid) return supR3HardenedSetError3(VERR_SUPLIB_NOT_SAME_OBJECT, pErrInfo, "The native handle is not the same as '", pszPath, "' (uid/gid)"); if ( (pFsObjState1->Stat.st_mode & (S_IFMT | S_IWUSR | S_IWGRP | S_IWOTH)) != (pFsObjState2->Stat.st_mode & (S_IFMT | S_IWUSR | S_IWGRP | S_IWOTH))) return supR3HardenedSetError3(VERR_SUPLIB_NOT_SAME_OBJECT, pErrInfo, "The native handle is not the same as '", pszPath, "' (mode)"); return VINF_SUCCESS; #endif } /** * Verifies a file system object (file or directory). * * @returns VBox status code, error buffer filled on failure. * @param pFsObjState The file system object information/state to be * verified. * @param fDir Whether this is a directory or a file. * @param fRelaxed Whether we can be more relaxed about this * directory (only used for grand parent * directories). * @param fSymlinksAllowed Flag whether symlinks are allowed or not. * If allowed the symlink object is verified not the target. * @param pszPath The path to the object. For error messages and * securing a couple of hacks. * @param pErrInfo The error info structure. */ static int supR3HardenedVerifyFsObject(PCSUPR3HARDENEDFSOBJSTATE pFsObjState, bool fDir, bool fRelaxed, bool fSymlinksAllowed, const char *pszPath, PRTERRINFO pErrInfo) { #if defined(RT_OS_WINDOWS) /** @todo Windows hardening. */ RT_NOREF(pFsObjState, fDir, fRelaxed, fSymlinksAllowed, pszPath, pErrInfo); return VINF_SUCCESS; #elif defined(RT_OS_OS2) /* No hardening here - it's a single user system. */ RT_NOREF(pFsObjState, fDir, fRelaxed, fSymlinksAllowed, pszPath, pErrInfo); return VINF_SUCCESS; #else /* * The owner must be root. * * This can be extended to include predefined system users if necessary. */ if (pFsObjState->Stat.st_uid != 0) return supR3HardenedSetError3(VERR_SUPLIB_OWNER_NOT_ROOT, pErrInfo, "The owner is not root: '", pszPath, "'"); /* * The object type must be directory or file. It can be a symbolic link * if explicitely allowed. Otherwise this and other risky stuff is not allowed * (sorry dude, but we're paranoid on purpose here). */ if ( !S_ISLNK(pFsObjState->Stat.st_mode) || !fSymlinksAllowed) { if ( !S_ISDIR(pFsObjState->Stat.st_mode) && !S_ISREG(pFsObjState->Stat.st_mode)) { if (S_ISLNK(pFsObjState->Stat.st_mode)) return supR3HardenedSetError3(VERR_SUPLIB_SYMLINKS_ARE_NOT_PERMITTED, pErrInfo, "Symlinks are not permitted: '", pszPath, "'"); return supR3HardenedSetError3(VERR_SUPLIB_NOT_DIR_NOT_FILE, pErrInfo, "Not regular file or directory: '", pszPath, "'"); } if (fDir != !!S_ISDIR(pFsObjState->Stat.st_mode)) { if (S_ISDIR(pFsObjState->Stat.st_mode)) return supR3HardenedSetError3(VERR_SUPLIB_IS_DIRECTORY, pErrInfo, "Expected file but found directory: '", pszPath, "'"); return supR3HardenedSetError3(VERR_SUPLIB_IS_FILE, pErrInfo, "Expected directory but found file: '", pszPath, "'"); } } /* * The group does not matter if it does not have write access, if it has * write access it must be group 0 (root/wheel/whatever). * * This can be extended to include predefined system groups or groups that * only root is member of. */ if ( (pFsObjState->Stat.st_mode & S_IWGRP) && pFsObjState->Stat.st_gid != 0) { # ifdef RT_OS_DARWIN /* HACK ALERT: On Darwin /Applications is root:admin with admin having full access. So, to work around we relax the hardening a bit and permit grand parents and beyond to be group writable by admin. */ /** @todo dynamically resolve the admin group? */ bool fBad = !fRelaxed || pFsObjState->Stat.st_gid != 80 /*admin*/ || suplibHardenedStrCmp(pszPath, "/Applications"); # elif defined(RT_OS_FREEBSD) /* HACK ALERT: PC-BSD 9 has group-writable /usr/pib directory which is similar to /Applications on OS X (see above). On FreeBSD root is normally the only member of this group, on PC-BSD the default user is a member. */ /** @todo dynamically resolve the operator group? */ bool fBad = !fRelaxed || pFsObjState->Stat.st_gid != 5 /*operator*/ || suplibHardenedStrCmp(pszPath, "/usr/pbi"); NOREF(fRelaxed); # elif defined(RT_OS_SOLARIS) /* HACK ALERT: Solaris has group-writable /usr/lib/iconv directory from which the appropriate module is loaded. By default only root and daemon are part of that group. . */ /** @todo dynamically resolve the bin group? */ bool fBad = !fRelaxed || pFsObjState->Stat.st_gid != 2 /*bin*/ || suplibHardenedStrCmp(pszPath, "/usr/lib/iconv"); # else NOREF(fRelaxed); bool fBad = true; # endif if (fBad) return supR3HardenedSetError3(VERR_SUPLIB_WRITE_NON_SYS_GROUP, pErrInfo, "An unknown (and thus untrusted) group has write access to '", pszPath, "' and we therefore cannot trust the directory content or that of any subdirectory"); } /* * World must not have write access. There is no relaxing this rule. * Linux exception: Symbolic links are always give permission 0777, there * is no lchmod or lchown APIs. The permissions on parent * directory that contains the symbolic link is what is * decising wrt to modifying it. (Caller is expected not * to allow symbolic links in the first path component.) */ if ( (pFsObjState->Stat.st_mode & S_IWOTH) # ifdef RT_OS_LINUX && ( !S_ISLNK(pFsObjState->Stat.st_mode) || !fSymlinksAllowed /* paranoia */) # endif ) return supR3HardenedSetError3(VERR_SUPLIB_WORLD_WRITABLE, pErrInfo, "World writable: '", pszPath, "'"); /* * Check the ACLs. */ /** @todo */ return VINF_SUCCESS; #endif } /** * Verifies that the file system object indicated by the native handle is the * same as the one @a pFsObjState indicates. * * @returns VBox status code, error buffer filled on failure. * @param hNative The native handle to the object @a pszPath * specifies and this should be verified to be the * same file system object. * @param pFsObjState The information/state returned by a previous * query call. * @param pszPath The path to the object @a pFsObjState * describes. (For the error message.) * @param pErrInfo The error info structure. */ static int supR3HardenedVerifySameFsObject(RTHCUINTPTR hNative, PCSUPR3HARDENEDFSOBJSTATE pFsObjState, const char *pszPath, PRTERRINFO pErrInfo) { SUPR3HARDENEDFSOBJSTATE FsObjState2; int rc = supR3HardenedQueryFsObjectByHandle(hNative, &FsObjState2, pszPath, pErrInfo); if (RT_SUCCESS(rc)) rc = supR3HardenedIsSameFsObject(pFsObjState, &FsObjState2, pszPath, pErrInfo); return rc; } /** * Does the recursive directory enumeration. * * @returns VBox status code, error buffer filled on failure. * @param pszDirPath The path buffer containing the subdirectory to * enumerate followed by a slash (this is never * the root slash). The buffer is RTPATH_MAX in * size and anything starting at @a cchDirPath * - 1 and beyond is scratch space. * @param cchDirPath The length of the directory path + slash. * @param pFsObjState Pointer to the file system object state buffer. * On input this will hold the stats for * the directory @a pszDirPath indicates and will * be used to verified that we're opening the same * thing. * @param fRecursive Whether to recurse into subdirectories. * @param pErrInfo The error info structure. */ static int supR3HardenedVerifyDirRecursive(char *pszDirPath, size_t cchDirPath, PSUPR3HARDENEDFSOBJSTATE pFsObjState, bool fRecursive, PRTERRINFO pErrInfo) { #if defined(RT_OS_WINDOWS) /** @todo Windows hardening. */ RT_NOREF5(pszDirPath, cchDirPath, pFsObjState, fRecursive, pErrInfo); return VINF_SUCCESS; #elif defined(RT_OS_OS2) /* No hardening here - it's a single user system. */ RT_NOREF5(pszDirPath, cchDirPath, pFsObjState, fRecursive, pErrInfo); return VINF_SUCCESS; #else /* * Open the directory. Now, we could probably eliminate opendir here * and go down on kernel API level (open + getdents for instance), however * that's not very portable and hopefully not necessary. */ DIR *pDir = opendir(pszDirPath); if (!pDir) { /* Ignore access errors. */ if (errno == EACCES) return VINF_SUCCESS; return supR3HardenedSetErrorN(VERR_SUPLIB_DIR_ENUM_FAILED, pErrInfo, 5, "opendir failed with ", strerror(errno), " on '", pszDirPath, "'"); } if (dirfd(pDir) != -1) { int rc = supR3HardenedVerifySameFsObject(dirfd(pDir), pFsObjState, pszDirPath, pErrInfo); if (RT_FAILURE(rc)) { closedir(pDir); return rc; } } /* * Enumerate the directory, check all the requested bits. */ int rc = VINF_SUCCESS; for (;;) { pszDirPath[cchDirPath] = '\0'; /* for error messages. */ struct dirent Entry; struct dirent *pEntry; #if RT_GNUC_PREREQ(4, 6) # pragma GCC diagnostic push # pragma GCC diagnostic ignored "-Wdeprecated-declarations" #endif int iErr = readdir_r(pDir, &Entry, &pEntry); #if RT_GNUC_PREREQ(4, 6) # pragma GCC diagnostic pop #endif if (iErr) { rc = supR3HardenedSetErrorN(VERR_SUPLIB_DIR_ENUM_FAILED, pErrInfo, 5, "readdir_r failed with ", strerror(iErr), " in '", pszDirPath, "'"); break; } if (!pEntry) break; /* * Check the length and copy it into the path buffer so it can be * stat()'ed. */ size_t cchName = suplibHardenedStrLen(pEntry->d_name); if (cchName + cchDirPath > SUPR3HARDENED_MAX_PATH) { rc = supR3HardenedSetErrorN(VERR_SUPLIB_PATH_TOO_LONG, pErrInfo, 4, "Path grew too long during recursion: '", pszDirPath, pEntry->d_name, "'"); break; } suplibHardenedMemCopy(&pszDirPath[cchName], pEntry->d_name, cchName + 1); /* * Query the information about the entry and verify it. * (We don't bother skipping '.' and '..' at this point, a little bit * of extra checks doesn't hurt and neither requires relaxed handling.) */ rc = supR3HardenedQueryFsObjectByPath(pszDirPath, pFsObjState, pErrInfo); if (RT_SUCCESS(rc)) break; rc = supR3HardenedVerifyFsObject(pFsObjState, S_ISDIR(pFsObjState->Stat.st_mode), false /*fRelaxed*/, false /*fSymlinksAllowed*/, pszDirPath, pErrInfo); if (RT_FAILURE(rc)) break; /* * Recurse into subdirectories if requested. */ if ( fRecursive && S_ISDIR(pFsObjState->Stat.st_mode) && suplibHardenedStrCmp(pEntry->d_name, ".") && suplibHardenedStrCmp(pEntry->d_name, "..")) { pszDirPath[cchDirPath + cchName] = RTPATH_SLASH; pszDirPath[cchDirPath + cchName + 1] = '\0'; rc = supR3HardenedVerifyDirRecursive(pszDirPath, cchDirPath + cchName + 1, pFsObjState, fRecursive, pErrInfo); if (RT_FAILURE(rc)) break; } } closedir(pDir); return VINF_SUCCESS; #endif } /** * Worker for SUPR3HardenedVerifyDir. * * @returns See SUPR3HardenedVerifyDir. * @param pszDirPath See SUPR3HardenedVerifyDir. * @param fRecursive See SUPR3HardenedVerifyDir. * @param fCheckFiles See SUPR3HardenedVerifyDir. * @param pErrInfo See SUPR3HardenedVerifyDir. */ DECLHIDDEN(int) supR3HardenedVerifyDir(const char *pszDirPath, bool fRecursive, bool fCheckFiles, PRTERRINFO pErrInfo) { /* * Validate the input path and parse it. */ SUPR3HARDENEDPATHINFO Info; int rc = supR3HardenedVerifyPathSanity(pszDirPath, pErrInfo, &Info); if (RT_FAILURE(rc)) return rc; /* * Verify each component from the root up. */ SUPR3HARDENEDFSOBJSTATE FsObjState; uint32_t const cComponents = Info.cComponents; for (uint32_t iComponent = 0; iComponent < cComponents; iComponent++) { bool fRelaxed = iComponent + 2 < cComponents; Info.szPath[Info.aoffComponents[iComponent + 1] - 1] = '\0'; rc = supR3HardenedQueryFsObjectByPath(Info.szPath, &FsObjState, pErrInfo); if (RT_SUCCESS(rc)) rc = supR3HardenedVerifyFsObject(&FsObjState, true /*fDir*/, fRelaxed, false /*fSymlinksAllowed*/, Info.szPath, pErrInfo); if (RT_FAILURE(rc)) return rc; Info.szPath[Info.aoffComponents[iComponent + 1] - 1] = iComponent + 1 != cComponents ? RTPATH_SLASH : '\0'; } /* * Check files and subdirectories if requested. */ if (fCheckFiles || fRecursive) { Info.szPath[Info.cch] = RTPATH_SLASH; Info.szPath[Info.cch + 1] = '\0'; return supR3HardenedVerifyDirRecursive(Info.szPath, Info.cch + 1, &FsObjState, fRecursive, pErrInfo); } return VINF_SUCCESS; } /** * Verfies a file. * * @returns VBox status code, error buffer filled on failure. * @param pszFilename The file to verify. * @param hNativeFile Handle to the file, verify that it's the same * as we ended up with when verifying the path. * RTHCUINTPTR_MAX means NIL here. * @param fMaybe3rdParty Set if the file is could be a supplied by a * third party. Different validation rules may * apply to 3rd party code on some platforms. * @param pErrInfo Where to return extended error information. * Optional. */ DECLHIDDEN(int) supR3HardenedVerifyFile(const char *pszFilename, RTHCUINTPTR hNativeFile, bool fMaybe3rdParty, PRTERRINFO pErrInfo) { /* * Validate the input path and parse it. */ SUPR3HARDENEDPATHINFO Info; int rc = supR3HardenedVerifyPathSanity(pszFilename, pErrInfo, &Info); if (RT_FAILURE(rc)) return rc; if (Info.fDirSlash) return supR3HardenedSetError3(VERR_SUPLIB_IS_DIRECTORY, pErrInfo, "The file path specifies a directory: '", pszFilename, "'"); /* * Verify each component from the root up. */ SUPR3HARDENEDFSOBJSTATE FsObjState; uint32_t const cComponents = Info.cComponents; for (uint32_t iComponent = 0; iComponent < cComponents; iComponent++) { bool fFinal = iComponent + 1 == cComponents; bool fRelaxed = iComponent + 2 < cComponents; Info.szPath[Info.aoffComponents[iComponent + 1] - 1] = '\0'; rc = supR3HardenedQueryFsObjectByPath(Info.szPath, &FsObjState, pErrInfo); if (RT_SUCCESS(rc)) rc = supR3HardenedVerifyFsObject(&FsObjState, !fFinal /*fDir*/, fRelaxed, false /*fSymlinksAllowed*/, Info.szPath, pErrInfo); if (RT_FAILURE(rc)) return rc; Info.szPath[Info.aoffComponents[iComponent + 1] - 1] = !fFinal ? RTPATH_SLASH : '\0'; } /* * Verify the file handle against the last component, if specified. */ if (hNativeFile != RTHCUINTPTR_MAX) { rc = supR3HardenedVerifySameFsObject(hNativeFile, &FsObjState, Info.szPath, pErrInfo); if (RT_FAILURE(rc)) return rc; } #ifdef RT_OS_WINDOWS /* * The files shall be signed on windows, verify that. */ rc = VINF_SUCCESS; HANDLE hVerify; if (hNativeFile == RTHCUINTPTR_MAX) { PRTUTF16 pwszPath; rc = RTStrToUtf16(pszFilename, &pwszPath); if (RT_SUCCESS(rc)) { hVerify = CreateFileW(pwszPath, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL); RTUtf16Free(pwszPath); } else { rc = RTErrInfoSetF(pErrInfo, rc, "Error converting '%s' to UTF-16: %Rrc", pszFilename, rc); hVerify = INVALID_HANDLE_VALUE; } } else { NTSTATUS rcNt = NtDuplicateObject(NtCurrentProcess(), (HANDLE)hNativeFile, NtCurrentProcess(), &hVerify, GENERIC_READ, 0 /*HandleAttributes*/, 0 /*Options*/); if (!NT_SUCCESS(rcNt)) hVerify = INVALID_HANDLE_VALUE; } if (hVerify != INVALID_HANDLE_VALUE) { # ifdef VBOX_WITH_HARDENING uint32_t fFlags = SUPHNTVI_F_REQUIRE_KERNEL_CODE_SIGNING; if (!fMaybe3rdParty) fFlags = SUPHNTVI_F_REQUIRE_BUILD_CERT; const char *pszSuffix = RTPathSuffix(pszFilename); if ( pszSuffix && pszSuffix[0] == '.' && ( RT_C_TO_LOWER(pszSuffix[1]) == 'r' || RT_C_TO_LOWER(pszSuffix[1]) == 'g') && RT_C_TO_LOWER(pszSuffix[2]) == 'c' && pszSuffix[3] == '\0' ) fFlags |= SUPHNTVI_F_RC_IMAGE; # ifndef IN_SUP_R3_STATIC /* Not in VBoxCpuReport and friends. */ rc = supHardenedWinVerifyImageByHandleNoName(hVerify, fFlags, pErrInfo); # endif # else RT_NOREF1(fMaybe3rdParty); # endif NtClose(hVerify); } else if (RT_SUCCESS(rc)) rc = RTErrInfoSetF(pErrInfo, RTErrConvertFromWin32(RtlGetLastWin32Error()), "Error %u trying to open (or duplicate handle for) '%s'", RtlGetLastWin32Error(), pszFilename); if (RT_FAILURE(rc)) return rc; #else RT_NOREF1(fMaybe3rdParty); #endif return VINF_SUCCESS; } #if defined(RT_OS_DARWIN) || defined(RT_OS_LINUX) /** * Verfies a file following symlinks. * * @returns VBox status code, error buffer filled on failure. * @param pszFilename The file to verify. * @param hNativeFile Handle to the file, verify that it's the same * as we ended up with when verifying the path. * RTHCUINTPTR_MAX means NIL here. * @param fMaybe3rdParty Set if the file is could be a supplied by a * third party. Different validation rules may * apply to 3rd party code on some platforms. * @param pErrInfo Where to return extended error information. * Optional. * * @note This is only used on OS X for libraries loaded with dlopen() because * the frameworks use symbolic links to point to the relevant library. * * @sa supR3HardenedVerifyFile */ DECLHIDDEN(int) supR3HardenedVerifyFileFollowSymlinks(const char *pszFilename, RTHCUINTPTR hNativeFile, bool fMaybe3rdParty, PRTERRINFO pErrInfo) { RT_NOREF1(fMaybe3rdParty); /* * Validate the input path and parse it. */ SUPR3HARDENEDPATHINFO Info; int rc = supR3HardenedVerifyPathSanity(pszFilename, pErrInfo, &Info); if (RT_FAILURE(rc)) return rc; if (Info.fDirSlash) return supR3HardenedSetError3(VERR_SUPLIB_IS_DIRECTORY, pErrInfo, "The file path specifies a directory: '", pszFilename, "'"); /* * Verify each component from the root up. */ #ifndef SUP_HARDENED_VERIFY_FOLLOW_SYMLINKS_USE_REALPATH uint32_t iLoops = 0; #endif SUPR3HARDENEDFSOBJSTATE FsObjState; uint32_t iComponent = 0; while (iComponent < Info.cComponents) { bool fFinal = iComponent + 1 == Info.cComponents; bool fRelaxed = iComponent + 2 < Info.cComponents; Info.szPath[Info.aoffComponents[iComponent + 1] - 1] = '\0'; rc = supR3HardenedQueryFsObjectByPath(Info.szPath, &FsObjState, pErrInfo); if (RT_SUCCESS(rc)) { /* * In case the component is a symlink expand it and start from the beginning after * verifying it has the proper access rights. * Furthermore only allow symlinks which don't contain any .. or . in the target * (enforced by supR3HardenedVerifyPathSanity). */ rc = supR3HardenedVerifyFsObject(&FsObjState, !fFinal /*fDir*/, fRelaxed, true /*fSymlinksAllowed*/, Info.szPath, pErrInfo); if ( RT_SUCCESS(rc) && S_ISLNK(FsObjState.Stat.st_mode)) { #if SUP_HARDENED_VERIFY_FOLLOW_SYMLINKS_USE_REALPATH /* Another approach using realpath() and verifying the result when encountering a symlink. */ char *pszFilenameResolved = realpath(pszFilename, NULL); if (pszFilenameResolved) { rc = supR3HardenedVerifyFile(pszFilenameResolved, hNativeFile, fMaybe3rdParty, pErrInfo); free(pszFilenameResolved); return rc; } else { int iErr = errno; supR3HardenedError(VERR_ACCESS_DENIED, false /*fFatal*/, "supR3HardenedVerifyFileFollowSymlinks: Failed to resolve the real path '%s': %s (%d)\n", pszFilename, strerror(iErr), iErr); return supR3HardenedSetError4(VERR_ACCESS_DENIED, pErrInfo, "realpath failed for '", pszFilename, "': ", strerror(iErr)); } #else /* Don't loop forever. */ iLoops++; if (iLoops < 8) { /* * Construct new path by replacing the current component by the symlink value. * Note! readlink() is a weird API that doesn't necessarily indicates if the * buffer is too small. */ char szPath[RTPATH_MAX]; size_t const cchBefore = Info.aoffComponents[iComponent]; /* includes slash */ size_t const cchAfter = fFinal ? 0 : 1 /*slash*/ + Info.cch - Info.aoffComponents[iComponent + 1]; if (sizeof(szPath) > cchBefore + cchAfter + 2) { ssize_t cchTarget = readlink(Info.szPath, szPath, sizeof(szPath) - 1); if (cchTarget > 0) { /* Some serious paranoia against embedded zero terminator and weird return values. */ szPath[cchTarget] = '\0'; size_t cchLink = strlen(szPath); /* Strip trailing dirslashes of non-final link. */ if (!fFinal) while (cchLink > 1 and szPath[cchLink - 1] == '/') cchLink--; /* Check link value sanity and buffer size. */ if (cchLink == 0) return supR3HardenedSetError3(VERR_ACCESS_DENIED, pErrInfo, "Bad readlink return for '", Info.szPath, "'"); if (szPath[0] == '/') return supR3HardenedSetError3(VERR_ACCESS_DENIED, pErrInfo, "Absolute symbolic link not allowed: '", szPath, "'"); if (cchBefore + cchLink + cchAfter + 1 /*terminator*/ > sizeof(szPath)) return supR3HardenedSetError(VERR_SUPLIB_PATH_TOO_LONG, pErrInfo, "Symlinks causing too long path!"); /* Construct the new path. */ if (cchBefore) memmove(&szPath[cchBefore], &szPath[0], cchLink); memcpy(&szPath[0], Info.szPath, cchBefore); if (!cchAfter) szPath[cchBefore + cchLink] = '\0'; else { szPath[cchBefore + cchLink] = RTPATH_SLASH; memcpy(&szPath[cchBefore + cchLink + 1], &Info.szPath[Info.aoffComponents[iComponent + 1]], cchAfter); /* cchAfter includes a zero terminator */ } /* Parse, copy and check the sanity (no '..' or '.') of the altered path. */ rc = supR3HardenedVerifyPathSanity(szPath, pErrInfo, &Info); if (RT_FAILURE(rc)) return rc; if (Info.fDirSlash) return supR3HardenedSetError3(VERR_SUPLIB_IS_DIRECTORY, pErrInfo, "The file path specifies a directory: '", szPath, "'"); /* Restart from the current component. */ continue; } int iErr = errno; supR3HardenedError(VERR_ACCESS_DENIED, false /*fFatal*/, "supR3HardenedVerifyFileFollowSymlinks: Failed to readlink '%s': %s (%d)\n", Info.szPath, strerror(iErr), iErr); return supR3HardenedSetError4(VERR_ACCESS_DENIED, pErrInfo, "readlink failed for '", Info.szPath, "': ", strerror(iErr)); } return supR3HardenedSetError(VERR_SUPLIB_PATH_TOO_LONG, pErrInfo, "Path too long for symlink replacing!"); } else return supR3HardenedSetError3(VERR_TOO_MANY_SYMLINKS, pErrInfo, "Too many symbolic links: '", pszFilename, "'"); #endif } } if (RT_FAILURE(rc)) return rc; Info.szPath[Info.aoffComponents[iComponent + 1] - 1] = !fFinal ? RTPATH_SLASH : '\0'; iComponent++; } /* * Verify the file handle against the last component, if specified. */ if (hNativeFile != RTHCUINTPTR_MAX) { rc = supR3HardenedVerifySameFsObject(hNativeFile, &FsObjState, Info.szPath, pErrInfo); if (RT_FAILURE(rc)) return rc; } return VINF_SUCCESS; } #endif /* RT_OS_DARWIN || RT_OS_LINUX */ /** * Gets the pre-init data for the hand-over to the other version * of this code. * * The reason why we pass this information on is that it contains * open directories and files. Later it may include even more info * (int the verified arrays mostly). * * The receiver is supR3HardenedRecvPreInitData. * * @param pPreInitData Where to store it. */ DECLHIDDEN(void) supR3HardenedGetPreInitData(PSUPPREINITDATA pPreInitData) { pPreInitData->cInstallFiles = RT_ELEMENTS(g_aSupInstallFiles); pPreInitData->paInstallFiles = &g_aSupInstallFiles[0]; pPreInitData->paVerifiedFiles = &g_aSupVerifiedFiles[0]; pPreInitData->cVerifiedDirs = RT_ELEMENTS(g_aSupVerifiedDirs); pPreInitData->paVerifiedDirs = &g_aSupVerifiedDirs[0]; } /** * Receives the pre-init data from the static executable stub. * * @returns VBox status code. Will not bitch on failure since the * runtime isn't ready for it, so that is left to the exe stub. * * @param pPreInitData The hand-over data. */ DECLHIDDEN(int) supR3HardenedRecvPreInitData(PCSUPPREINITDATA pPreInitData) { /* * Compare the array lengths and the contents of g_aSupInstallFiles. */ if ( pPreInitData->cInstallFiles != RT_ELEMENTS(g_aSupInstallFiles) || pPreInitData->cVerifiedDirs != RT_ELEMENTS(g_aSupVerifiedDirs)) return VERR_VERSION_MISMATCH; SUPINSTFILE const *paInstallFiles = pPreInitData->paInstallFiles; for (unsigned iFile = 0; iFile < RT_ELEMENTS(g_aSupInstallFiles); iFile++) if ( g_aSupInstallFiles[iFile].enmDir != paInstallFiles[iFile].enmDir || g_aSupInstallFiles[iFile].enmType != paInstallFiles[iFile].enmType || g_aSupInstallFiles[iFile].fOptional != paInstallFiles[iFile].fOptional || suplibHardenedStrCmp(g_aSupInstallFiles[iFile].pszFile, paInstallFiles[iFile].pszFile)) return VERR_VERSION_MISMATCH; /* * Check that we're not called out of order. * If dynamic linking it screwed up, we may end up here. */ if ( !ASMMemIsZero(&g_aSupVerifiedFiles[0], sizeof(g_aSupVerifiedFiles)) || !ASMMemIsZero(&g_aSupVerifiedDirs[0], sizeof(g_aSupVerifiedDirs))) return VERR_WRONG_ORDER; /* * Copy the verification data over. */ suplibHardenedMemCopy(&g_aSupVerifiedFiles[0], pPreInitData->paVerifiedFiles, sizeof(g_aSupVerifiedFiles)); suplibHardenedMemCopy(&g_aSupVerifiedDirs[0], pPreInitData->paVerifiedDirs, sizeof(g_aSupVerifiedDirs)); return VINF_SUCCESS; }