internal/linker: add working patches for Go 1.21 (master)

From https://github.com/burrowers/go-patches/pull/4.
1 year ago · 6e1e750755
parent 14daadbf85
commit 6e1e750755
3 changed files with 165 additions and 0 deletions
--- a/internal/linker/patches/go1.21/0001-add-custom-magic-value.patch
+++ b/internal/linker/patches/go1.21/0001-add-custom-magic-value.patch
@ -0,0 +1,36 @@
+From 62c7b9ef34098c1feddb18502331068277479875 Mon Sep 17 00:00:00 2001
+From: pagran <pagran@protonmail.com>
+Date: Mon, 9 Jan 2023 13:30:00 +0100
+Subject: [PATCH 1/3] add custom magic value
+
+---
+ cmd/link/internal/ld/pcln.go | 13 +++++++++++++
+ 1 file changed, 13 insertions(+)
+
+diff --git a/cmd/link/internal/ld/pcln.go b/cmd/link/internal/ld/pcln.go
+index aaf8ddef51..e93532e510 100644
+--- a/cmd/link/internal/ld/pcln.go
+++ b/cmd/link/internal/ld/pcln.go
+@@ -249,6 +249,19 @@ func (state *pclntab) generatePCHeader(ctxt *Link) {
+ 		if off != size {
+ 			panic(fmt.Sprintf("pcHeader size: %d != %d", off, size))
+ 		}
+
+		// Use garble prefix in variable names to minimize collision risk
+		garbleMagicStr := os.Getenv("GARBLE_LINK_MAGIC")
+		if garbleMagicStr == "" {
+			panic("[garble] magic value must be set")
+		}
+		var garbleMagicVal uint32
+		// Use fmt package instead of strconv to avoid importing a new package
+		if _, err := fmt.Sscan(garbleMagicStr, &garbleMagicVal); err != nil {
+			panic(fmt.Errorf("[garble] invalid magic value %s: %v", garbleMagicStr, err))
+		}
+
+		header.SetUint32(ctxt.Arch, 0, garbleMagicVal)
+ 	}
+ 
+ 	state.pcheader = state.addGeneratedSym(ctxt, "runtime.pcheader", size, writeHeader)
+-- 
+2.40.1
+
--- a/internal/linker/patches/go1.21/0002-add-unexported-function-name-removing.patch
+++ b/internal/linker/patches/go1.21/0002-add-unexported-function-name-removing.patch
@ -0,0 +1,86 @@
+From 1e3895a863cb122b8262b5bf51a2984998f0fd3e Mon Sep 17 00:00:00 2001
+From: pagran <pagran@protonmail.com>
+Date: Mon, 9 Jan 2023 13:30:36 +0100
+Subject: [PATCH 2/3] add unexported function name removing
+
+---
+ cmd/link/internal/ld/pcln.go | 44 +++++++++++++++++++++++++++++++++++-
+ 1 file changed, 43 insertions(+), 1 deletion(-)
+
+diff --git a/cmd/link/internal/ld/pcln.go b/cmd/link/internal/ld/pcln.go
+index e93532e510..8b670135de 100644
+--- a/cmd/link/internal/ld/pcln.go
+++ b/cmd/link/internal/ld/pcln.go
+@@ -4,6 +4,11 @@
+ 
+ package ld
+ 
+import (
+	"strings"
+	"unicode"
+)
+
+ import (
+ 	"cmd/internal/goobj"
+ 	"cmd/internal/objabi"
+@@ -301,19 +306,56 @@ func walkFuncs(ctxt *Link, funcs []loader.Sym, f func(loader.Sym)) {
+ func (state *pclntab) generateFuncnametab(ctxt *Link, funcs []loader.Sym) map[loader.Sym]uint32 {
+ 	nameOffsets := make(map[loader.Sym]uint32, state.nfunc)
+ 
+	garbleTiny := os.Getenv("GARBLE_LINK_TINY") == "true"
+
+ 	// Write the null terminated strings.
+ 	writeFuncNameTab := func(ctxt *Link, s loader.Sym) {
+ 		symtab := ctxt.loader.MakeSymbolUpdater(s)
+		if garbleTiny {
+			symtab.AddStringAt(0, "")
+		}
+
+ 		for s, off := range nameOffsets {
+			if garbleTiny && off == 0 {
+				continue
+			}
+ 			symtab.AddCStringAt(int64(off), ctxt.loader.SymName(s))
+ 		}
+ 	}
+ 
+ 	// Loop through the CUs, and calculate the size needed.
+ 	var size int64
+
+	if garbleTiny {
+		size = 1 // first byte is reserved for empty string used for all non-exportable method names
+	}
+	// Kinds of SymNames found in the wild:
+	//
+	// * reflect.Value.CanAddr
+	// * reflect.(*Value).String
+	// * reflect.w6cEoKc
+	// * internal/abi.(*RegArgs).IntRegArgAddr
+	// * type:.eq.runtime.special
+	// * runtime/internal/atomic.(*Pointer[go.shape.string]).Store
+	//
+	// Checking whether the first rune after the last dot is uppercase seems enough.
+	isExported := func(name string) bool {
+		for _, r := range name[strings.LastIndexByte(name, '.')+1:] {
+			return unicode.IsUpper(r)
+		}
+		return false
+	}
+
+ 	walkFuncs(ctxt, funcs, func(s loader.Sym) {
+		name := ctxt.loader.SymName(s)
+
+		if garbleTiny && !isExported(name) {
+			nameOffsets[s] = 0 // redirect name to empty string
+			return
+		}
+
+ 		nameOffsets[s] = uint32(size)
+-		size += int64(len(ctxt.loader.SymName(s)) + 1) // NULL terminate
+		size += int64(len(name) + 1) // NULL terminate
+ 	})
+ 
+ 	state.funcnametab = state.addGeneratedSym(ctxt, "runtime.funcnametab", size, writeFuncNameTab)
+-- 
+2.40.1
+
--- a/internal/linker/patches/go1.21/0003-add-entryOff-encryption.patch
+++ b/internal/linker/patches/go1.21/0003-add-entryOff-encryption.patch
@ -0,0 +1,43 @@
+From b5524a7c84a994b43027723b4bb05441db365a1e Mon Sep 17 00:00:00 2001
+From: pagran <pagran@protonmail.com>
+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 8b670135de..e4ccfc9330 100644
+--- a/cmd/link/internal/ld/pcln.go
+++ b/cmd/link/internal/ld/pcln.go
+@@ -779,6 +779,26 @@ func writeFuncs(ctxt *Link, sb *loader.SymbolBuilder, funcs []loader.Sym, inlSym
+ 			sb.SetUint32(ctxt.Arch, dataoff, uint32(ldr.SymValue(fdsym)-gofuncBase))
+ 		}
+ 	}
+
+	// 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
+-- 
+2.40.1
+