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fix: amd64, offset read error issue for PIE executable. PR #516 #517

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Merged
merged 2 commits into from
Apr 12, 2024
Merged

fix: amd64, offset read error issue for PIE executable. PR #516 #517

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28952a5
fix: amd64, offset read error issue for PIE executable.
cfc4n Apr 10, 2024
68abc6e
user: Remove redundant address calculation logic
cfc4n Apr 12, 2024
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36 changes: 10 additions & 26 deletions user/config/config_gotls.go
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Original file line number Diff line number Diff line change
Expand Up @@ -34,12 +34,12 @@ const (
)

var (
ErrorGoBINNotFound = errors.New("The executable program (compiled by Golang) was not found")
ErrorSymbolEmpty = errors.New("symbol is empty")
ErrorSymbolNotFound = errors.New("symbol not found")
ErrorSymbolNotFoundFromTable = errors.New("symbol not found from table")
ErrorNoRetFound = errors.New("no RET instructions found")
ErrorNoRetFoundFromSymTabFun = errors.New("no RET instructions found from golang symbol table with Fun")
ErrorGoBINNotFound = errors.New("The executable program (compiled by Golang) was not found")
ErrorSymbolEmpty = errors.New("symbol is empty")
ErrorSymbolNotFound = errors.New("symbol not found")
ErrorSymbolNotFoundFromTable = errors.New("symbol not found from table")
ErrorNoRetFound = errors.New("no RET instructions found")
ErrorNoFuncFoundFromSymTabFun = errors.New("no function found from golang symbol table with Func Name")
)

// From go/src/debug/gosym/pclntab.go
Expand Down Expand Up @@ -339,8 +339,9 @@ func (gc *GoTLSConfig) findRetOffsetsPie(lfunc string) ([]int, error) {
if prog.Type != elf.PT_LOAD || (prog.Flags&elf.PF_X) == 0 {
continue
}
// via https://github.com/golang/go/blob/a65a2bbd8e58cd77dbff8a751dbd6079424beb05/src/cmd/internal/objfile/elf.go#L174
data := make([]byte, funcLen)
_, err = prog.ReadAt(data, int64(address))
_, err = prog.ReadAt(data, int64(address-prog.Vaddr))
if err != nil {
return offsets, fmt.Errorf("finding function return: %w", err)
}
Expand All @@ -359,24 +360,7 @@ func (gc *GoTLSConfig) findRetOffsetsPie(lfunc string) ([]int, error) {
func (gc *GoTLSConfig) findPieSymbolAddr(lfunc string) (uint64, error) {
f := gc.goSymTab.LookupFunc(lfunc)
if f == nil {
return 0, errors.New("Cant found symbol address on pie model.")
return 0, ErrorNoFuncFoundFromSymTabFun
}
var err error
for _, prog := range gc.goElf.Progs {
if prog.Type != elf.PT_LOAD || (prog.Flags&elf.PF_X) == 0 {
continue
}
// For more info on this calculation: stackoverflow.com/a/40249502
if prog.Vaddr <= f.Value && f.Value < (prog.Vaddr+prog.Memsz) {
funcLen := f.End - f.Entry
data := make([]byte, funcLen)
address := f.Value - prog.Vaddr + prog.Off
_, err = prog.ReadAt(data, int64(address))
if err != nil {
return 0, fmt.Errorf("search function return: %w", err)
}
return address, nil
}
}
return 0, ErrorNoRetFoundFromSymTabFun
return f.Value, nil
}