Index: /trunk/src/VBox/HostDrivers/Support/posix/SUPR3HardenedMain-posix.cpp
===================================================================
--- /trunk/src/VBox/HostDrivers/Support/posix/SUPR3HardenedMain-posix.cpp	(revision 66605)
+++ /trunk/src/VBox/HostDrivers/Support/posix/SUPR3HardenedMain-posix.cpp	(revision 66605)
@@ -0,0 +1,660 @@
+/* $Id$ */
+/** @file
+ * VirtualBox Support Library - Hardened main(), posix bits.
+ */
+
+/*
+ * Copyright (C) 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                                                                                                                 *
+*********************************************************************************************************************************/
+#include <VBox/err.h>
+#include <VBox/dis.h>
+#include <VBox/sup.h>
+
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include <iprt/x86.h>
+
+#include <dlfcn.h>
+#include <sys/mman.h>
+#ifdef RT_OS_DARWIN
+# include <errno.h>
+# include <fcntl.h>
+# include <sys/stat.h> /* fstat() */
+# include <unistd.h>   /* readlink() */
+# include <stdlib.h>
+#elif defined(RT_OS_SOLARIS)
+# include <link.h>
+#endif
+#include <stdio.h>
+#include <stdint.h>
+
+#include "SUPLibInternal.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+
+/** For OS X. */
+#ifndef MAP_ANONYMOUS
+# define MAP_ANONYMOUS MAP_ANON
+#endif
+
+/**
+ * Memory for code patching.
+ */
+#define DLOPEN_PATCH_MEMORY_SIZE   _4K
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Callback (SUPHARDENEDPOSIXHOOK::pfnResolv) for triggering lazy GOT resolver.
+ *
+ * This generally just calls the API in a harmless manner and triggers the lazy
+ * resolving of the symbol, ensuring a proper address in the GOT/PLT entry.
+ *
+ * On Solaris dlsym() will return the value in the GOT/PLT entry.  We don't wish
+ * to patch the lazy loader trampoline function, but rather the real function!
+ */
+typedef DECLCALLBACK(void) FNSUPHARDENEDSYMRESOLVE(void);
+/** Pointer to FNSUPHARDENEDSYMRESOLVE. */
+typedef FNSUPHARDENEDSYMRESOLVE *PFNSUPHARDENEDSYMRESOLVE;
+
+/**
+ * A hook descriptor.
+ */
+typedef struct SUPHARDENEDPOSIXHOOK
+{
+    /** The symbol to hook. */
+    const char              *pszSymbol;
+    /** The intercepting wrapper doing additional checks. */
+    PFNRT                    pfnHook;
+    /** Where to store the pointer to the code into patch memory
+     * which resumes the original call. */
+    PFNRT                   *ppfnRealResume;
+    /** Pointer to the resolver method used on Solaris. */
+    PFNSUPHARDENEDSYMRESOLVE pfnResolve;
+} SUPHARDENEDPOSIXHOOK;
+/** Pointer to a hook descriptor. */
+typedef SUPHARDENEDPOSIXHOOK *PSUPHARDENEDPOSIXHOOK;
+/** Pointer to a const hook descriptor. */
+typedef const SUPHARDENEDPOSIXHOOK *PCSUPHARDENEDPOSIXHOOK;
+
+/** dlopen() declaration. */
+typedef void *FNDLOPEN(const char *pszFilename, int fFlags);
+/** Pointer to dlopen. */
+typedef FNDLOPEN *PFNDLOPEN;
+
+#ifdef SUP_HARDENED_WITH_DLMOPEN
+/** dlmopen() declaration */
+typedef void *FNDLMOPEN(Lmid_t idLm, const char *pszFilename, int fFlags);
+/** Pointer to dlmopen. */
+typedef FNDLMOPEN *PFNDLMOPEN;
+#endif
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+static FNSUPHARDENEDSYMRESOLVE supR3HardenedPosixMonitorDlopenResolve;
+#ifdef SUP_HARDENED_WITH_DLMOPEN
+static FNSUPHARDENEDSYMRESOLVE supR3HardenedPosixMonitorDlmopenResolve;
+#endif
+
+/* SUPR3HardenedMainA-posix.asm: */
+DECLASM(void) supR3HardenedPosixMonitor_Dlopen(const char *pszFilename, int fFlags);
+#ifdef SUP_HARDENED_WITH_DLMOPEN
+DECLASM(void) supR3HardenedPosixMonitor_Dlmopen(Lmid_t idLm, const char *pszFilename, int fFlags);
+#endif
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+RT_C_DECLS_BEGIN
+/** Resume patch for dlopen(), jumped to form assembly stub. */
+DECLHIDDEN(PFNDLOPEN)  g_pfnDlopenReal  = NULL;
+#ifdef SUP_HARDENED_WITH_DLMOPEN
+/** Resume patch for dlmopen(), jumped to form assembly stub. */
+DECLHIDDEN(PFNDLMOPEN) g_pfnDlmopenReal = NULL;
+#endif
+RT_C_DECLS_END
+
+/** Memory allocated for the patches. */
+static uint8_t *g_pbExecMemory = NULL;
+/** Offset into the patch memory which is not used. */
+static uint32_t g_offExecMemory = 0;
+
+/**
+ * Array of hooks to install.
+ */
+static SUPHARDENEDPOSIXHOOK const g_aHooks[] =
+{
+    /* pszSymbol,       pfnHook,                                     ppfnRealResume,   pfnResolve */
+    { "dlopen",  (PFNRT)supR3HardenedPosixMonitor_Dlopen,  (PFNRT *)&g_pfnDlopenReal,  supR3HardenedPosixMonitorDlopenResolve  },
+#ifdef SUP_HARDENED_WITH_DLMOPEN
+    { "dlmopen", (PFNRT)supR3HardenedPosixMonitor_Dlmopen, (PFNRT *)&g_pfnDlmopenReal, supR3HardenedPosixMonitorDlmopenResolve }
+#endif
+};
+
+
+
+/**
+ * Verifies the given library for proper access rights for further loading
+ * into the process.
+ *
+ * @returns Flag whether the access rights of the library look sane and loading
+ *          it is not considered a security risk. Returns true if the library
+ *          looks sane, false otherwise.
+ * @param   pszFilename         The library to load, this can be an absolute or relative path
+ *                              or just the filename of the library when the default paths should
+ *                              be searched. NULL is allowed too to indicate opening the main
+ *                              binary.
+ */
+DECLASM(bool) supR3HardenedPosixMonitor_VerifyLibrary(const char *pszFilename)
+{
+    /*
+     * Giving NULL as the filename indicates opening the main program which is fine
+     * We are already loaded and executing after all.
+     *
+     * Filenames without any path component (whether absolute or relative) are allowed
+     * unconditionally too as the loader will only search the default paths configured by root.
+     */
+    bool fAllow = true;
+
+    if (   pszFilename
+        && strchr(pszFilename, '/') != NULL)
+    {
+#ifdef RT_OS_DARWIN
+        int rc = supR3HardenedVerifyFileFollowSymlinks(pszFilename, RTHCUINTPTR_MAX, true /* fMaybe3rdParty */,
+                                                       NULL /* pErrInfo */);
+#else
+        int rc = supR3HardenedVerifyFile(pszFilename, RTHCUINTPTR_MAX, true /* fMaybe3rdParty */,
+                                         NULL /* pErrInfo */);
+#endif
+
+        if (RT_FAILURE(rc))
+            fAllow = false;
+    }
+
+    return fAllow;
+}
+
+
+/**
+ * Returns the start address of the given symbol if found or NULL otherwise.
+ *
+ * @returns Start address of the symbol or NULL if not found.
+ * @param   pszSymbol           The symbol name.
+ * @param   pfnResolve          The resolver to call before trying to query the start address.
+ */
+static void *supR3HardenedMainPosixGetStartBySymbol(const char *pszSymbol, PFNSUPHARDENEDSYMRESOLVE pfnResolve)
+{
+#ifndef RT_OS_SOLARIS
+    return dlsym(RTLD_DEFAULT, pszSymbol);
+    RT_NOREF(pfnResolve);
+
+#else  /* RT_OS_SOLARIS */
+    /*
+     * Solaris is tricky as dlsym doesn't return the actual start address of
+     * the symbol but the start of the trampoline in the PLT of the caller.
+     *
+     * Disassemble the first jmp instruction to get at the entry in the global
+     * offset table where the actual address is stored.
+     *
+     * To counter lazy symbol resolving, we first have to call the API before
+     * trying to resolve and disassemble it.
+     */
+    pfnResolve();
+
+    uint8_t *pbSym = (uint8_t *)dlsym(RTLD_DEFAULT, pszSymbol);
+
+# ifdef RT_ARCH_AMD64
+    DISSTATE Dis;
+    uint32_t cbInstr = 1;
+    int rc = DISInstr(pbSym, DISCPUMODE_64BIT, &Dis, &cbInstr);
+    if (   RT_FAILURE(rc)
+        || Dis.pCurInstr->uOpcode != OP_JMP
+        || !(Dis.ModRM.Bits.Mod == 0 && Dis.ModRM.Bits.Rm == 5 /* wrt RIP */))
+        return NULL;
+
+    /* Extract start address. */
+    pbSym = (pbSym + cbInstr + Dis.Param1.uDisp.i32);
+    pbSym = (uint8_t *)*((uintptr_t *)pbSym);
+# else
+#  error "Unsupported architecture"
+# endif
+
+    return pbSym;
+#endif /* RT_OS_SOLARIS */
+}
+
+
+/**
+ * Allocates executable patch memory with the given constraints.
+ *
+ * @returns VBox status code.
+ * @param   cb                  Size of the patch memory in bytes.
+ * @param   pvHint              Where to try allocating nearby.
+ * @param   fRipRelAddr         Flag whether the executable memory must be within
+ *                              2GB before or after the hint as it will contain
+ *                              instructions using RIP relative addressing
+ */
+static uint8_t *supR3HardenedMainPosixExecMemAlloc(size_t cb, void *pvHint, bool fRipRelAddr)
+{
+    AssertReturn(cb < _1K, NULL);
+
+    /* Lazy allocation of exectuable memory. */
+    if (!g_pbExecMemory)
+    {
+        g_pbExecMemory = (uint8_t *)mmap(pvHint, DLOPEN_PATCH_MEMORY_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC,
+                                         MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+        g_offExecMemory = 0;
+        if (g_pbExecMemory == MAP_FAILED)
+            return NULL;
+
+        memset(g_pbExecMemory, 0xcc, DLOPEN_PATCH_MEMORY_SIZE);
+    }
+
+    if (g_offExecMemory + cb >= DLOPEN_PATCH_MEMORY_SIZE)
+        return NULL;
+
+    uint8_t *pb = &g_pbExecMemory[g_offExecMemory];
+
+    if (fRipRelAddr)
+    {
+        /* Check that we allocated within 2GB of the hint. */
+        uintptr_t uPtrHint     = (uintptr_t)pvHint;
+        uintptr_t uPtrPatchMem = (uintptr_t)pb;
+        uintptr_t cbDistance   = uPtrHint < uPtrPatchMem
+                               ? uPtrPatchMem - uPtrHint
+                               : uPtrHint - uPtrPatchMem;
+
+        if (cbDistance >= _2G - _4K)
+            return NULL;
+    }
+
+    g_offExecMemory = RT_ALIGN_32(g_offExecMemory + cb, 16);
+    return pb;
+}
+
+
+/**
+ * Hooks the given method to execute the given one first.
+ *
+ * @returns VBox status code.
+ * @param   pszSymbol           The symbol to hook.
+ * @param   pfnHook             The hook to install.
+ * @param   ppfnReal            Where to store the pointer to entry point of the real method
+ *                              (somewhere in patch memory).
+ * @param   pfnResolve          The resolver to call before trying to query the start address.
+ */
+static int supR3HardenedMainPosixHookOne(const char *pszSymbol, PFNRT pfnHook, PFNRT *ppfnReal,
+                                         PFNSUPHARDENEDSYMRESOLVE pfnResolve)
+{
+    void *pfnTarget = supR3HardenedMainPosixGetStartBySymbol(pszSymbol, pfnResolve);
+    if (!pfnTarget)
+        return VERR_NOT_FOUND;
+
+    /*
+     * Make the target memory writeable to be able to insert the patch.
+     * Unprotect two pages in case the code crosses a page boundary.
+     */
+    void *pvTargetBase = (void *)(((uintptr_t)pfnTarget) & ~(uintptr_t)(_4K - 1));
+    int rcPsx = mprotect(pvTargetBase, 2 * _4K, PROT_WRITE | PROT_READ | PROT_EXEC);
+    if (rcPsx == -1)
+        return VERR_SUPLIB_TEXT_NOT_WRITEABLE;
+
+    uint8_t * const pbTarget = (uint8_t *)(uintptr_t)pfnTarget;
+
+    DISSTATE Dis;
+    uint32_t cbInstr;
+    uint32_t offJmpBack = 0;
+    uint32_t cbPatchMem = 0;
+
+#ifdef RT_ARCH_AMD64
+    /*
+     * Patch 64-bit hosts.
+     */
+    uint32_t cRipRelMovs = 0;
+
+    /* Just use the disassembler to skip 12 bytes or more, we might need to
+       rewrite mov instructions using RIP relative addressing. */
+    while (offJmpBack < 12)
+    {
+        cbInstr = 1;
+        int rc = DISInstr(pbTarget + offJmpBack, DISCPUMODE_64BIT, &Dis, &cbInstr);
+        if (   RT_FAILURE(rc)
+            || (Dis.pCurInstr->fOpType & DISOPTYPE_CONTROLFLOW)
+            || (   Dis.ModRM.Bits.Mod == 0
+                && Dis.ModRM.Bits.Rm  == 5 /* wrt RIP */
+                && Dis.pCurInstr->uOpcode != OP_MOV))
+            return VERR_SUPLIB_UNEXPECTED_INSTRUCTION;
+
+        if (Dis.ModRM.Bits.Mod == 0 && Dis.ModRM.Bits.Rm == 5 /* wrt RIP */)
+            cRipRelMovs++;
+
+        offJmpBack += cbInstr;
+        cbPatchMem += cbInstr;
+    }
+
+    cbPatchMem += 14; /* jmp qword [$+8 wrt RIP] + 8 byte address to jump to. */
+    cbPatchMem = RT_ALIGN_32(cbPatchMem, 8);
+
+    /* Allocate suitable exectuable memory available. */
+    bool fConvRipRelMovs = false;
+    uint8_t *pbPatchMem = supR3HardenedMainPosixExecMemAlloc(cbPatchMem, pbTarget, cRipRelMovs > 0);
+    if (!pbPatchMem)
+    {
+        /*
+         * Try to allocate memory again without the RIP relative mov addressing constraint
+         * Makes it a bit more difficult for us later on but there is no way around it.
+         * We need to increase the patch memory because we create two instructions for one
+         * (7 bytes for the RIP relative mov vs. 13 bytes for the two instructions replacing it ->
+         * need to allocate 6 bytes more per RIP relative mov).
+         */
+        fConvRipRelMovs = true;
+        if (cRipRelMovs > 0)
+            pbPatchMem = supR3HardenedMainPosixExecMemAlloc(cbPatchMem + cRipRelMovs * 6,
+                                                            pbTarget, false /*fRipRelAddr*/);
+
+        if (!pbPatchMem)
+            return VERR_NO_MEMORY;
+    }
+
+    /* Assemble the code for resuming the call.*/
+    *ppfnReal = (PFNRT)(uintptr_t)pbPatchMem;
+
+    /* Go through the instructions to patch and fixup any rip relative mov instructions. */
+    uint32_t offInsn = 0;
+    while (offInsn < offJmpBack)
+    {
+        cbInstr = 1;
+        int rc = DISInstr(pbTarget + offInsn, DISCPUMODE_64BIT, &Dis, &cbInstr);
+        if (   RT_FAILURE(rc)
+            || (Dis.pCurInstr->fOpType & DISOPTYPE_CONTROLFLOW))
+            return VERR_SUPLIB_UNEXPECTED_INSTRUCTION;
+
+        if (   Dis.ModRM.Bits.Mod == 0
+            && Dis.ModRM.Bits.Rm  == 5 /* wrt RIP */
+            && Dis.pCurInstr->uOpcode == OP_MOV)
+        {
+            /* Deduce destination register and write out new instruction. */
+            if (RT_UNLIKELY(!(   (Dis.Param1.fUse & (DISUSE_BASE | DISUSE_REG_GEN64))
+                              && (Dis.Param2.fUse & DISUSE_RIPDISPLACEMENT32))))
+                return VERR_SUPLIB_UNEXPECTED_INSTRUCTION;
+
+            uintptr_t uAddr = (uintptr_t)&pbTarget[offInsn + cbInstr] + (intptr_t)Dis.Param2.uDisp.i32;
+
+            if (fConvRipRelMovs)
+            {
+                /*
+                 * Create two instructions, first one moves the address as a constant to the destination register
+                 * and the second one loads the data from the memory into the destination register.
+                 */
+
+                *pbPatchMem++ = 0x48;
+                *pbPatchMem++ = 0xb8 + Dis.Param1.Base.idxGenReg;
+                *(uintptr_t *)pbPatchMem = uAddr;
+                pbPatchMem   += sizeof(uintptr_t);
+
+                *pbPatchMem++ = 0x48;
+                *pbPatchMem++ = 0x8b;
+                *pbPatchMem++ = (Dis.Param1.Base.idxGenReg << X86_MODRM_REG_SHIFT) | Dis.Param1.Base.idxGenReg;
+            }
+            else
+            {
+                intptr_t  iDispNew   = uAddr - (uintptr_t)&pbPatchMem[3 + sizeof(int32_t)];
+                Assert(iDispNew == (int32_t)iDispNew);
+
+                /* Assemble the mov to register instruction with the updated rip relative displacement. */
+                *pbPatchMem++ = 0x48;
+                *pbPatchMem++ = 0x8b;
+                *pbPatchMem++ = (Dis.Param1.Base.idxGenReg << X86_MODRM_REG_SHIFT) | 5;
+                *(int32_t *)pbPatchMem = (int32_t)iDispNew;
+                pbPatchMem   += sizeof(int32_t);
+            }
+        }
+        else
+        {
+            memcpy(pbPatchMem, pbTarget + offInsn, cbInstr);
+            pbPatchMem += cbInstr;
+        }
+
+        offInsn += cbInstr;
+    }
+
+    *pbPatchMem++ = 0xff; /* jmp qword [$+8 wrt RIP] */
+    *pbPatchMem++ = 0x25;
+    *(uint32_t *)pbPatchMem = (uint32_t)(RT_ALIGN_PT(pbPatchMem + 4, 8, uint8_t *) - (pbPatchMem + 4));
+    pbPatchMem = RT_ALIGN_PT(pbPatchMem + 4, 8, uint8_t *);
+    *(uint64_t *)pbPatchMem = (uintptr_t)&pbTarget[offJmpBack];
+
+    /* Assemble the patch. */
+    Assert(offJmpBack >= 12);
+    pbTarget[0]  = 0x48; /* mov rax, qword */
+    pbTarget[1]  = 0xb8;
+    *(uintptr_t *)&pbTarget[2] = (uintptr_t)pfnHook;
+    pbTarget[10] = 0xff; /* jmp rax */
+    pbTarget[11] = 0xe0;
+
+#else  /* !RT_ARCH_AMD64 */
+    /*
+     * Patch 32-bit hosts.
+     */
+    /* Just use the disassembler to skip 5 bytes or more. */
+    while (offJmpBack < 5)
+    {
+        cbInstr = 1;
+        int rc = DISInstr(pbTarget + offJmpBack, DISCPUMODE_32BIT, &Dis, &cbInstr);
+        if (   RT_FAILURE(rc)
+            || (   (Dis.pCurInstr->fOpType & DISOPTYPE_CONTROLFLOW)
+                && Dis.pCurInstr->uOpcode != OP_CALL))
+            return VERR_SUPLIB_UNEXPECTED_INSTRUCTION;
+
+        if (   Dis.pCurInstr->uOpcode == OP_CALL
+            && (Dis.pCurInstr->fOpType & DISOPTYPE_RELATIVE_CONTROLFLOW))
+            cbPatchMem += 10; /* push imm32 + jmp rel32 */
+        else
+            cbPatchMem += cbInstr;
+
+        offJmpBack += cbInstr;
+    }
+
+    /* Allocate suitable exectuable memory available. */
+    uint8_t *pbPatchMem = supR3HardenedMainPosixExecMemAlloc(cbPatchMem, pbTarget, false /* fRipRelAddr */);
+    if (!pbPatchMem)
+        return VERR_NO_MEMORY;
+
+    /* Assemble the code for resuming the call.*/
+    *ppfnReal = (PFNRT)pbPatchMem;
+
+    /* Go through the instructions to patch and fixup any relative call instructions. */
+    uint32_t offInsn = 0;
+    while (offInsn < offJmpBack)
+    {
+        cbInstr = 1;
+        int rc = DISInstr(pbTarget + offInsn, DISCPUMODE_32BIT, &Dis, &cbInstr);
+        if (   RT_FAILURE(rc)
+            || (   (Dis.pCurInstr->fOpType & DISOPTYPE_CONTROLFLOW)
+                && Dis.pCurInstr->uOpcode != OP_CALL))
+            return VERR_SUPLIB_UNEXPECTED_INSTRUCTION;
+
+        if (   Dis.pCurInstr->uOpcode == OP_CALL
+            && (Dis.pCurInstr->fOpType & DISOPTYPE_RELATIVE_CONTROLFLOW))
+        {
+            /*
+             * Don't use a call instruction directly but push the original return address
+             * onto the stack and use a relative jump to the call target.
+             * The reason here is that on Linux the called method saves the return
+             * address from the stack which will be different from the original because
+             * the code is executed from our patch memory.
+             *
+             * Luckily the call instruction is 5 bytes long which means it is always the
+             * last instruction to patch and we don't need to return from the call
+             * to patch memory anyway but can use this method to resume the original call.
+             */
+            AssertReturn(offInsn + cbInstr >= offJmpBack, VERR_SUPLIB_UNEXPECTED_INSTRUCTION); /* Must be last instruction! */
+
+            /* push return address */
+            uint32_t const uAddrReturn = (uintptr_t)&pbTarget[offInsn + cbInstr]; /* The return address to push to the stack. */
+
+            *pbPatchMem++           = 0x68; /* push dword */
+            *(uint32_t *)pbPatchMem = uAddrReturn;
+            pbPatchMem             += sizeof(uint32_t);
+
+            /* jmp rel32 to the call target */
+            uintptr_t const uAddr      = uAddrReturn + (int32_t)Dis.Param1.uValue;
+            int32_t   const i32DispNew = uAddr - (uintptr_t)&pbPatchMem[5];
+
+            *pbPatchMem++          = 0xe9; /* jmp rel32 */
+            *(int32_t *)pbPatchMem = i32DispNew;
+            pbPatchMem            += sizeof(int32_t);
+        }
+        else
+        {
+            memcpy(pbPatchMem, pbTarget + offInsn, cbInstr);
+            pbPatchMem += cbInstr;
+        }
+
+        offInsn += cbInstr;
+    }
+
+    *pbPatchMem++ = 0xe9; /* jmp rel32 */
+    *(uint32_t *)pbPatchMem = (uintptr_t)&pbTarget[offJmpBack] - ((uintptr_t)pbPatchMem + 4);
+
+    /* Assemble the patch. */
+    Assert(offJmpBack >= 5);
+    pbTarget[0] = 0xe9;
+    *(uint32_t *)&pbTarget[1] = (uintptr_t)pfnHook - (uintptr_t)&pbTarget[1+4];
+#endif /* !RT_ARCH_AMD64 */
+
+    /*
+     * Re-seal target (ASSUMING that the shared object either has page aligned
+     * section or that the patch target is far enough from the writable parts).
+     */
+    rcPsx = mprotect(pvTargetBase, 2 * _4K, PROT_READ | PROT_EXEC);
+    if (rcPsx == -1)
+        return VERR_SUPLIB_TEXT_NOT_SEALED;
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * @callback_method_impl{FNSUPHARDENEDSYMRESOLVE, dlopen}
+ */
+static DECLCALLBACK(void) supR3HardenedPosixMonitorDlopenResolve(void)
+{
+    /* Make harmless dlopen call. */
+    void *pv = dlopen(NULL, RTLD_LAZY);
+    if (pv)
+        dlclose(pv);
+}
+
+
+#ifdef SUP_HARDENED_WITH_DLMOPEN
+/**
+ * @callback_method_impl{FNSUPHARDENEDSYMRESOLVE, dlmopen}
+ */
+static DECLCALLBACK(void) supR3HardenedPosixMonitorDlmopenResolve(void)
+{
+    /* Make harmless dlmopen call. */
+    void *pv = dlmopen(LM_ID_BASE, NULL, RTLD_LAZY);
+    if (pv)
+        dlclose(pv);
+}
+#endif
+
+
+/**
+ * Hardening initialization for POSIX compatible hosts.
+ *
+ * @returns nothing.
+ *
+ * @note Doesn't return on error.
+ */
+DECLHIDDEN(void) supR3HardenedPosixInit(void)
+{
+    for (unsigned i = 0; i < RT_ELEMENTS(g_aHooks); i++)
+    {
+        PCSUPHARDENEDPOSIXHOOK pHook = &g_aHooks[i];
+        int rc = supR3HardenedMainPosixHookOne(pHook->pszSymbol, pHook->pfnHook, pHook->ppfnRealResume, pHook->pfnResolve);
+        if (RT_FAILURE(rc))
+            supR3HardenedFatalMsg("supR3HardenedPosixInit", kSupInitOp_Integrity, rc,
+                                  "Failed to hook the %s interface", pHook->pszSymbol);
+    }
+}
+
+
+
+/*
+ * assert.cpp
+ *
+ * ASSUMES working DECLHIDDEN or there will be symbol confusion!
+ */
+
+RTDATADECL(char)                     g_szRTAssertMsg1[1024];
+RTDATADECL(char)                     g_szRTAssertMsg2[4096];
+RTDATADECL(const char * volatile)    g_pszRTAssertExpr;
+RTDATADECL(const char * volatile)    g_pszRTAssertFile;
+RTDATADECL(uint32_t volatile)        g_u32RTAssertLine;
+RTDATADECL(const char * volatile)    g_pszRTAssertFunction;
+
+RTDECL(bool) RTAssertMayPanic(void)
+{
+    return true;
+}
+
+
+RTDECL(void) RTAssertMsg1(const char *pszExpr, unsigned uLine, const char *pszFile, const char *pszFunction)
+{
+    /*
+     * Fill in the globals.
+     */
+    g_pszRTAssertExpr       = pszExpr;
+    g_pszRTAssertFile       = pszFile;
+    g_pszRTAssertFunction   = pszFunction;
+    g_u32RTAssertLine       = uLine;
+    snprintf(g_szRTAssertMsg1, sizeof(g_szRTAssertMsg1),
+             "\n!!Assertion Failed!!\n"
+             "Expression: %s\n"
+             "Location  : %s(%d) %s\n",
+             pszExpr, pszFile, uLine, pszFunction);
+}
+
+
+RTDECL(void) RTAssertMsg2V(const char *pszFormat, va_list va)
+{
+    vsnprintf(g_szRTAssertMsg2, sizeof(g_szRTAssertMsg2), pszFormat, va);
+    if (g_enmSupR3HardenedMainState < SUPR3HARDENEDMAINSTATE_CALLED_TRUSTED_MAIN)
+        supR3HardenedFatalMsg(g_pszRTAssertExpr, kSupInitOp_Misc, VERR_INTERNAL_ERROR,
+                              "%s%s", g_szRTAssertMsg1,  g_szRTAssertMsg2);
+    else
+        supR3HardenedError(VERR_INTERNAL_ERROR, false/*fFatal*/, "%s%s", g_szRTAssertMsg1,  g_szRTAssertMsg2);
+}
+
Index: /trunk/src/VBox/HostDrivers/Support/posix/SUPR3HardenedMainA-posix.asm
===================================================================
--- /trunk/src/VBox/HostDrivers/Support/posix/SUPR3HardenedMainA-posix.asm	(revision 66605)
+++ /trunk/src/VBox/HostDrivers/Support/posix/SUPR3HardenedMainA-posix.asm	(revision 66605)
@@ -0,0 +1,160 @@
+; $Id$
+;; @file
+; VirtualBox Support Library - Hardened main(), Posix assembly bits.
+;
+
+;
+; Copyright (C) 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                                                                *
+;*******************************************************************************
+%include "iprt/asmdefs.mac"
+
+
+;*********************************************************************************************************************************
+;*  External Symbols                                                                                                             *
+;*********************************************************************************************************************************
+; External code.
+BEGINCODE
+extern NAME(supR3HardenedPosixMonitor_VerifyLibrary)
+
+; External data
+BEGINDATA
+extern NAME(g_pfnDlopenReal)
+%ifdef SUP_HARDENED_WITH_DLMOPEN
+extern NAME(g_pfnDlmopenReal)
+%endif
+
+
+
+BEGINCODE
+
+;;
+; Wrapper for dlopen() handing the call over to the file verification code
+; and resuming the call if we get a green light to load the library.
+;
+align 16
+BEGINPROC supR3HardenedPosixMonitor_Dlopen
+        push    xBP
+        mov     xBP, xSP
+
+%ifdef RT_ARCH_AMD64
+        ; Save parameters on the stack
+        push    rdi
+        push    rsi
+%else
+        sub     esp, 4                  ; 16-byte stack alignment before call.
+        push    dword [xBP + 08h]       ; first parameter.
+%endif
+
+        ;
+        ; Call the verification method.
+        ;
+        call    NAME(supR3HardenedPosixMonitor_VerifyLibrary)
+
+        ;
+        ; Restore parameters for the next call and get the stack back to the
+        ; original state.
+        ;
+%ifdef RT_ARCH_AMD64
+        pop     rsi
+        pop     rdi
+%endif
+        leave
+
+        ; Check the result and resume the call if the result is positive,
+        ; otherwise clean up and return NULL
+        test    al, al
+        je short .failed
+
+        ; Resume the original dlopen call by jumping into the saved code.
+        jmp     [NAME(g_pfnDlopenReal) xWrtRIP]
+
+.failed:
+        ;
+        ; Don't use leave here as we didn't use the enter instruction. Just clear
+        ; xAX and return
+        ;
+        xor     xAX, xAX
+        ret
+ENDPROC   supR3HardenedPosixMonitor_Dlopen
+
+
+%ifdef SUP_HARDENED_WITH_DLMOPEN
+;;
+; Wrapper for dlmopen() handing the call over to the file verification code
+; and resuming the call if we get a green light to load the library.
+;
+align 16
+BEGINPROC supR3HardenedPosixMonitor_Dlmopen
+        push    xBP
+        mov     xBP, xSP
+
+%ifdef RT_ARCH_AMD64
+        sub     rsp, 8                  ; 16-byte stack alignment before call.
+
+        ; Save parameters on the stack
+        push    rdi
+        push    rsi
+        push    rdx
+
+        mov     rdi, rsi                ; Move the second parameter to the front
+%else
+        sub     esp, 4                  ; 16-byte stack alignment before call.
+        push    dword [xBP + 0ch]       ; Move the second parameter to the front
+%endif
+
+        ;
+        ; Call the verification method.
+        ;
+        call    NAME(supR3HardenedPosixMonitor_VerifyLibrary)
+
+        ;
+        ; Restore parameters for the next call and get the stack back to the
+        ; original state.
+        ;
+%ifdef RT_ARCH_AMD64
+        pop     rdx
+        pop     rsi
+        pop     rdi
+%endif
+        leave
+
+        ; Check the result and resume the call if the result is positive,
+        ; otherwise clean up and return NULL
+        test    al, al
+        je short .failed
+
+        ; Resume the original dlopen call by jumping into the saved code.
+        jmp     [NAME(g_pfnDlmopenReal) xWrtRIP]
+
+.failed:
+        ;
+        ; Don't use leave here as we didn't use the enter instruction. Just clear
+        ; xAX and return
+        ;
+        xor     xAX, xAX
+        ret
+ENDPROC   supR3HardenedPosixMonitor_Dlmopen
+%endif
+
