From 16b978956b323d88ef4a48dbef124304f5206e90 Mon Sep 17 00:00:00 2001 From: pagran Date: Sat, 14 Jan 2023 21:36:16 +0100 Subject: [PATCH 3/3] add entryOff encryption --- cmd/link/internal/ld/pcln.go | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/cmd/link/internal/ld/pcln.go b/cmd/link/internal/ld/pcln.go index c47b9eab72..d58338f7c3 100644 --- a/cmd/link/internal/ld/pcln.go +++ b/cmd/link/internal/ld/pcln.go @@ -980,6 +980,26 @@ func writeFuncs(ctxt *Link, sb *loader.SymbolBuilder, funcs []loader.Sym, inlSym sb.SetUint32(ctxt.Arch, dataoff, uint32(ldr.SymValue(fdsym))) } } + + // Moving next code higher is not recommended. + // Only at the end of the current function no edits between go versions + garbleEntryOffKeyStr := os.Getenv("GARBLE_LINK_ENTRYOFF_KEY") + if garbleEntryOffKeyStr == "" { + panic("[garble] entryOff key must be set") + } + var garbleEntryOffKey uint32 + // Use fmt package instead of strconv to avoid importing a new package + if _, err := fmt.Sscan(garbleEntryOffKeyStr, &garbleEntryOffKey); err != nil { + panic(fmt.Errorf("[garble] invalid entryOff key %s: %v", garbleEntryOffKeyStr, err)) + } + + garbleData := sb.Data() + for _, off := range startLocations { + entryOff := ctxt.Arch.ByteOrder.Uint32(garbleData[off:]) + nameOff := ctxt.Arch.ByteOrder.Uint32(garbleData[off+4:]) + + sb.SetUint32(ctxt.Arch, int64(off), entryOff^(nameOff*garbleEntryOffKey)) + } } // pclntab initializes the pclntab symbol with -- 2.53.0