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/*
* Copyright 2002-2019 Intel Corporation.
*
* This software is provided to you as Sample Source Code as defined in the accompanying
* End User License Agreement for the Intel(R) Software Development Products ("Agreement")
* section 1.L.
*
* This software and the related documents are provided as is, with no express or implied
* warranties, other than those that are expressly stated in the License.
*/
#include "pin.H"
#include <iostream>
#include <fstream>
#include <unistd.h>
#include <elf.h>
#include <link.h>
#include <sys/mman.h>
static ADDRINT mainImageRelroAddr = 0;
static ADDRINT mainImageRelroSize = 0;
static ADDRINT mainImageRelroPageStart = 0;
static ADDRINT mainImageRelroPageSize = 0;
static ADDRINT relocatedMainImageRelroPageAddr = 0;
static bool relroUnmapped = false;
// Temporary registers used to rewrite memory operands
REG rewrite_reg[2];
/* ===================================================================== */
ADDRINT PageStart(ADDRINT p)
{
ADDRINT sz = (ADDRINT)getpagesize();
return (p & ~(sz - 1));
}
ADDRINT PageEnd(ADDRINT p)
{
ADDRINT sz = (ADDRINT)getpagesize();
return ((p + sz - 1) & ~(sz - 1));
}
/* ===================================================================== */
VOID ImageLoad(IMG img, VOID *v)
{
if (IMG_IsMainExecutable(img))
{
ElfW(Ehdr)* hdr = (ElfW(Ehdr)*)IMG_LowAddress(img);
ElfW(Phdr)* phdr = (ElfW(Phdr)*)((char*)hdr + hdr->e_phoff);
for (int i = 0; i < hdr->e_phnum; i++)
{
if (phdr[i].p_type == PT_GNU_RELRO)
{
mainImageRelroAddr = phdr[i].p_vaddr + IMG_LoadOffset(img);
mainImageRelroSize = phdr[i].p_memsz;
mainImageRelroPageStart = PageStart(mainImageRelroAddr);
mainImageRelroPageSize = PageEnd(mainImageRelroAddr + mainImageRelroSize) - mainImageRelroPageStart;
fprintf(stderr, "Main image's PT_RELRO is at [%p,%p]\n", (void*)mainImageRelroAddr, (void*)mainImageRelroSize);
break;
}
}
ASSERTX(0 != mainImageRelroAddr);
ASSERTX(0 != mainImageRelroSize);
}
else if (!IMG_IsInterpreter(img) && !IMG_IsVDSO(img) && !relroUnmapped)
{
// This is the first image which was actually loader by the loader
ASSERTX(0 != mainImageRelroAddr);
ASSERTX(0 != mainImageRelroSize);
relroUnmapped = true;
relocatedMainImageRelroPageAddr = (ADDRINT)mmap(NULL, mainImageRelroPageSize, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);
ASSERTX((ADDRINT)-1 != relocatedMainImageRelroPageAddr);
fprintf(stderr, "Moving [%p, %p] -> %p\n", (void*)mainImageRelroPageStart, (void*)mainImageRelroPageSize, (void*)relocatedMainImageRelroPageAddr);
memcpy((void*)relocatedMainImageRelroPageAddr, (void*)mainImageRelroPageStart, mainImageRelroPageSize);
mprotect((void*)relocatedMainImageRelroPageAddr, mainImageRelroPageSize, PROT_READ);
int res = munmap((void*)mainImageRelroPageStart, mainImageRelroPageSize);
ASSERTX(0 == res);
}
}
/*
* Translates a memory address.
* After we moved the PT_GNU_RELRO region to a different place in the memory,
* here we redirect all memory accesses to the original PT_GNU_RELRO region
* to the new region that they moved to.
*/
static ADDRINT TranslateMemRef(ADDRINT ea, ADDRINT pc)
{
if (0 == relocatedMainImageRelroPageAddr)
{
return ea;
}
if ((ea >= mainImageRelroPageStart) && (ea < (mainImageRelroPageStart + mainImageRelroPageSize)))
{
return ea - mainImageRelroPageStart + relocatedMainImageRelroPageAddr;
}
return ea;
}
// Pin calls this function every time a new instruction is encountered
VOID Instruction(INS ins, VOID *v)
{
const UINT32 memOps = INS_MemoryOperandCount(ins);
ASSERTX(memOps <= 2);
for (UINT32 i = 0 ; i < memOps; i++)
{
INS_InsertCall(ins, IPOINT_BEFORE, (AFUNPTR)TranslateMemRef,
IARG_MEMORYOP_EA, (ADDRINT)i,
IARG_REG_VALUE, REG_INST_PTR,
IARG_RETURN_REGS, rewrite_reg[i],
IARG_END);
INS_RewriteMemoryOperand(ins, i, rewrite_reg[i]);
}
}
/* ===================================================================== */
int main(int argc, CHAR *argv[])
{
PIN_InitSymbols();
PIN_Init(argc,argv);
rewrite_reg[0] = PIN_ClaimToolRegister();
rewrite_reg[1] = PIN_ClaimToolRegister();
IMG_AddInstrumentFunction(ImageLoad, NULL);
INS_AddInstrumentFunction(Instruction, NULL);
PIN_StartProgram();
return 1;
}
/* ===================================================================== */
/* eof */
/* ===================================================================== */