cmd: do not use notsha256

CL 402595 used notsha256 to prevent the compiler from depending on
cgo-based implementations of sha1 and sha256.

However, since CL 454836, cmd is built with CGO_ENABLED=0, which
will disable boringcrypto. Thus all usages of notsha256 is not necessary
anymore.

Updates #51940
Updates #64751

Change-Id: I503090f7a2efb5723e8a79523b143dc7cdb4edd0
Reviewed-on: https://go-review.googlesource.com/c/go/+/610596
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Keith Randall <khr@golang.org>

1 files changed, 5 insertions, 14 deletions

diff --git a/src/cmd/internal/codesign/codesign.go b/src/cmd/internal/codesign/codesign.go
index 1116393b5c..24496e2000 100644
--- a/src/cmd/internal/codesign/codesign.go
+++ b/src/cmd/internal/codesign/codesign.go
@@ -11,11 +11,12 @@
 package codesign
 
 import (
+	"crypto/sha256"
 	"debug/macho"
 	"encoding/binary"
 	"io"
 
-	"cmd/internal/notsha256"
+	"cmd/internal/hash"
 )
 
 // Code signature layout.
@@ -191,7 +192,7 @@ func Size(codeSize int64, id string) int64 {
 	nhashes := (codeSize + pageSize - 1) / pageSize
 	idOff := int64(codeDirectorySize)
 	hashOff := idOff + int64(len(id)+1)
-	cdirSz := hashOff + nhashes*notsha256.Size
+	cdirSz := hashOff + nhashes*hash.Size32
 	return int64(superBlobSize+blobSize) + cdirSz
 }
 
@@ -227,7 +228,7 @@ func Sign(out []byte, data io.Reader, id string, codeSize, textOff, textSize int
 		identOffset:  uint32(idOff),
 		nCodeSlots:   uint32(nhashes),
 		codeLimit:    uint32(codeSize),
-		hashSize:     notsha256.Size,
+		hashSize:     hash.Size32,
 		hashType:     CS_HASHTYPE_SHA256,
 		pageSize:     uint8(pageSizeBits),
 		execSegBase:  uint64(textOff),
@@ -246,12 +247,7 @@ func Sign(out []byte, data io.Reader, id string, codeSize, textOff, textSize int
 	outp = puts(outp, []byte(id+"\000"))
 
 	// emit hashes
-	// NOTE(rsc): These must be SHA256, but for cgo bootstrap reasons
-	// we cannot import crypto/sha256 when GOEXPERIMENT=boringcrypto
-	// and the host is linux/amd64. So we use NOT-SHA256
-	// and then apply a NOT ourselves to get SHA256. Sigh.
 	var buf [pageSize]byte
-	h := notsha256.New()
 	p := 0
 	for p < int(codeSize) {
 		n, err := io.ReadFull(data, buf[:])
@@ -265,12 +261,7 @@ func Sign(out []byte, data io.Reader, id string, codeSize, textOff, textSize int
 			n = int(codeSize) - p
 		}
 		p += n
-		h.Reset()
-		h.Write(buf[:n])
-		b := h.Sum(nil)
-		for i := range b {
-			b[i] ^= 0xFF // convert notsha256 to sha256
-		}
+		b := sha256.Sum256(buf[:n])
 		outp = puts(outp, b[:])
 	}
 }