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relocate.go
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relocate.go
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package goloader
import (
"fmt"
"strings"
"github.com/pkujhd/goloader/obj"
"github.com/pkujhd/goloader/objabi/reloctype"
"github.com/pkujhd/goloader/objabi/symkind"
"github.com/pkujhd/goloader/objabi/tls"
)
func (linker *Linker) relocateADRP(mCode []byte, loc obj.Reloc, segment *segment, symAddr uintptr) {
byteorder := linker.Arch.ByteOrder
offset := uint64(int64(symAddr) + int64(loc.Add) - ((int64(segment.codeBase) + int64(loc.Offset)) &^ 0xFFF))
//overflow
if offset > 0xFFFFFFFF {
if symAddr < 0xFFFFFFFF {
addr := byteorder.Uint32(mCode)
//low: MOV reg imm
low := uint32(0xD2800000)
//high: MOVK reg imm LSL#16
high := uint32(0xF2A00000)
low = ((addr & 0x1F) | low) | ((uint32(symAddr) & 0xFFFF) << 5)
high = ((addr & 0x1F) | high) | (uint32(symAddr) >> 16 << 5)
byteorder.PutUint64(mCode, uint64(low)|(uint64(high)<<32))
} else {
addr := byteorder.Uint32(mCode)
blcode := byteorder.Uint32(arm64BLcode)
blcode |= ((uint32(segment.offset) - uint32(loc.Offset)) >> 2) & 0x01FFFFFF
if segment.offset-loc.Offset < 0 {
blcode |= 0x02000000
}
byteorder.PutUint32(mCode, blcode)
//low: MOV reg imm
llow := uint32(0xD2800000)
//lhigh: MOVK reg imm LSL#16
lhigh := uint32(0xF2A00000)
//llow: MOVK reg imm LSL#32
hlow := uint32(0xF2C00000)
//lhigh: MOVK reg imm LSL#48
hhigh := uint32(0xF2E00000)
llow = ((addr & 0x1F) | llow) | ((uint32(symAddr) & 0xFFFF) << 5)
lhigh = ((addr & 0x1F) | lhigh) | (uint32(symAddr) >> 16 << 5)
putAddressAddOffset(byteorder, segment.codeByte, &segment.offset, uint64(llow)|(uint64(lhigh)<<32))
hlow = ((addr & 0x1F) | hlow) | uint32(((uint64(symAddr)>>32)&0xFFFF)<<5)
hhigh = ((addr & 0x1F) | hhigh) | uint32((uint64(symAddr)>>48)<<5)
putAddressAddOffset(byteorder, segment.codeByte, &segment.offset, uint64(hlow)|(uint64(hhigh)<<32))
blcode = byteorder.Uint32(arm64BLcode)
blcode |= ((uint32(loc.Offset) - uint32(segment.offset) + 8) >> 2) & 0x01FFFFFF
if loc.Offset-segment.offset+8 < 0 {
blcode |= 0x02000000
}
byteorder.PutUint32(segment.codeByte[segment.offset:], blcode)
segment.offset += Uint32Size
}
} else {
// 2bit + 19bit + low(12bit) = 33bit
low := (uint32((offset>>12)&3) << 29) | (uint32((offset>>12>>2)&0x7FFFF) << 5)
high := uint32(offset&0xFFF) << 10
value := byteorder.Uint64(mCode)
value = (uint64(uint32(value>>32)|high) << 32) | uint64(uint32(value&0xFFFFFFFF)|low)
byteorder.PutUint64(mCode, value)
}
}
func (linker *Linker) relocateCALL(addr uintptr, loc obj.Reloc, segment *segment, relocByte []byte, addrBase int) {
byteorder := linker.Arch.ByteOrder
offset := int(addr) - (addrBase + loc.Offset + loc.Size) + loc.Add
if offset > 0x7FFFFFFF || offset < -0x80000000 {
offset = (segment.codeBase + segment.offset) - (addrBase + loc.Offset + loc.Size)
copy(segment.codeByte[segment.offset:], x86amd64JMPLcode)
segment.offset += len(x86amd64JMPLcode)
putAddressAddOffset(byteorder, segment.codeByte, &segment.offset, uint64(addr)+uint64(loc.Add))
}
byteorder.PutUint32(relocByte[loc.Offset:], uint32(offset))
}
func (linker *Linker) relocatePCREL(addr uintptr, loc obj.Reloc, segment *segment, relocByte []byte, addrBase int) (err error) {
byteorder := linker.Arch.ByteOrder
offset := int(addr) - (addrBase + loc.Offset + loc.Size) + loc.Add
if offset > 0x7FFFFFFF || offset < -0x80000000 {
offset = (segment.codeBase + segment.offset) - (addrBase + loc.Offset + loc.Size)
bytes := relocByte[loc.Offset-2:]
opcode := relocByte[loc.Offset-2]
regsiter := ZeroByte
if opcode == x86amd64LEAcode {
bytes[0] = x86amd64MOVcode
} else if opcode == x86amd64MOVcode && loc.Size >= Uint32Size {
regsiter = ((relocByte[loc.Offset-1] >> 3) & 0x7) | 0xb8
copy(bytes, x86amd64JMPLcode)
} else if opcode == x86amd64CMPLcode && loc.Size >= Uint32Size {
copy(bytes, x86amd64JMPLcode)
} else {
return fmt.Errorf("not support code:%v!\n", relocByte[loc.Offset-2:loc.Offset])
}
byteorder.PutUint32(relocByte[loc.Offset:], uint32(offset))
if opcode == x86amd64CMPLcode || opcode == x86amd64MOVcode {
putAddressAddOffset(byteorder, segment.codeByte, &segment.offset, uint64(segment.codeBase+segment.offset+PtrSize))
if opcode == x86amd64CMPLcode {
copy(segment.codeByte[segment.offset:], x86amd64replaceCMPLcode)
segment.codeByte[segment.offset+0x0F] = relocByte[loc.Offset+loc.Size]
segment.offset += len(x86amd64replaceCMPLcode)
putAddressAddOffset(byteorder, segment.codeByte, &segment.offset, uint64(addr))
} else {
copy(segment.codeByte[segment.offset:], x86amd64replaceMOVQcode)
segment.codeByte[segment.offset+1] = regsiter
copy2Slice(segment.codeByte[segment.offset+2:], addr, PtrSize)
segment.offset += len(x86amd64replaceMOVQcode)
}
putAddressAddOffset(byteorder, segment.codeByte, &segment.offset, uint64(addrBase+loc.Offset+loc.Size-loc.Add))
} else {
putAddressAddOffset(byteorder, segment.codeByte, &segment.offset, uint64(addr))
}
} else {
byteorder.PutUint32(relocByte[loc.Offset:], uint32(offset))
}
return err
}
func (linker *Linker) relocteCALLARM(addr uintptr, loc obj.Reloc, segment *segment) {
byteorder := linker.Arch.ByteOrder
add := loc.Add
if loc.Type == reloctype.R_CALLARM {
add = int(signext24(int64(loc.Add&0xFFFFFF)) * 4)
}
offset := (int(addr) + add - (segment.codeBase + loc.Offset)) / 4
if offset > 0x7FFFFF || offset < -0x800000 {
segment.offset = alignof(segment.offset, PtrSize)
off := uint32(segment.offset-loc.Offset) / 4
if loc.Type == reloctype.R_CALLARM {
add = int(signext24(int64(loc.Add&0xFFFFFF)+2) * 4)
off = uint32(segment.offset-loc.Offset-8) / 4
}
putUint24(segment.codeByte[loc.Offset:], off)
if loc.Type == reloctype.R_CALLARM64 {
copy(segment.codeByte[segment.offset:], arm64code)
segment.offset += len(arm64code)
} else {
copy(segment.codeByte[segment.offset:], armcode)
segment.offset += len(armcode)
}
putAddressAddOffset(byteorder, segment.codeByte, &segment.offset, uint64(int(addr)+add))
} else {
val := byteorder.Uint32(segment.codeByte[loc.Offset:])
if loc.Type == reloctype.R_CALLARM {
val |= uint32(offset) & 0x00FFFFFF
} else {
val |= uint32(offset) & 0x03FFFFFF
}
byteorder.PutUint32(segment.codeByte[loc.Offset:], val)
}
}
func (linker *Linker) relocate(codeModule *CodeModule, symbolMap, symPtr map[string]uintptr) (err error) {
segment := &codeModule.segment
byteorder := linker.Arch.ByteOrder
for _, symbol := range linker.symMap {
// if the symbol exist in symPtr, so it doesnot need to relocate, the loader use the symbol in loader.
if _, ok := symPtr[symbol.Name]; !ok || strings.HasPrefix(symbol.Name, MainPkgPrefix) {
for _, loc := range symbol.Reloc {
addr := symbolMap[loc.Sym.Name]
sym := loc.Sym
relocByte := segment.codeByte[segment.codeLen:]
addrBase := segment.dataBase
if symbol.Kind == symkind.STEXT {
addrBase = segment.codeBase
relocByte = segment.codeByte
}
if addr == 0 && strings.HasPrefix(sym.Name, ItabPrefix) {
addr = uintptr(segment.dataBase + loc.Sym.Offset)
symbolMap[loc.Sym.Name] = addr
codeModule.module.itablinks = append(codeModule.module.itablinks, (*itab)(adduintptr(uintptr(segment.dataBase), loc.Sym.Offset)))
}
if addr != InvalidHandleValue {
switch loc.Type {
case reloctype.R_TLS_LE:
if _, ok := symbolMap[TLSNAME]; !ok {
symbolMap[TLSNAME] = tls.GetTLSOffset(linker.Arch, PtrSize)
}
byteorder.PutUint32(segment.codeByte[loc.Offset:], uint32(symbolMap[TLSNAME]))
case reloctype.R_CALL:
linker.relocateCALL(addr, loc, segment, relocByte, addrBase)
case reloctype.R_PCREL:
err = linker.relocatePCREL(addr, loc, segment, relocByte, addrBase)
case reloctype.R_CALLARM, reloctype.R_CALLARM64:
linker.relocteCALLARM(addr, loc, segment)
case reloctype.R_ADDRARM64:
if symbol.Kind != symkind.STEXT {
err = fmt.Errorf("impossible!Sym:%s locate not in code segment!\n", sym.Name)
}
linker.relocateADRP(segment.codeByte[loc.Offset:], loc, segment, addr)
case reloctype.R_ADDR, reloctype.R_WEAKADDR:
address := uintptr(int(addr) + loc.Add)
putAddress(byteorder, relocByte[loc.Offset:], uint64(address))
case reloctype.R_CALLIND:
//nothing todo
case reloctype.R_ADDROFF, reloctype.R_WEAKADDROFF, reloctype.R_METHODOFF:
if symbol.Kind == symkind.STEXT {
err = fmt.Errorf("impossible!Sym:%s locate on code segment!\n", sym.Name)
}
offset := int(addr) - segment.codeBase + loc.Add
if offset > 0x7FFFFFFF || offset < -0x80000000 {
err = fmt.Errorf("symName:%s offset:%d is overflow!\n", sym.Name, offset)
}
byteorder.PutUint32(segment.codeByte[segment.codeLen+loc.Offset:], uint32(offset))
case reloctype.R_USETYPE:
//nothing todo
case reloctype.R_USEIFACE:
//nothing todo
case reloctype.R_USEIFACEMETHOD:
//nothing todo
case reloctype.R_ADDRCUOFF:
//nothing todo
default:
err = fmt.Errorf("unknown reloc type:%d sym:%s", loc.Type, sym.Name)
}
}
if err != nil {
return err
}
}
}
}
return err
}