[dev.boringcrypto] crypto/internal/boring: make SHA calls allocation-free

The standard Go implementations are allocation-free.
Making the BoringCrypto ones the same helps avoid
surprises, including in some of our own tests.

For #51940.

Change-Id: Ic9c5dc46f5e29ca85f571244be2b380ec2cf89c9
Reviewed-on: https://go-review.googlesource.com/c/go/+/395876
Reviewed-by: Roland Shoemaker <roland@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>

1 files changed, 3 insertions, 12 deletions

diff --git a/src/crypto/sha512/sha512.go b/src/crypto/sha512/sha512.go
index 1285cca7ee6..c800a294a27 100644
--- a/src/crypto/sha512/sha512.go
+++ b/src/crypto/sha512/sha512.go
@@ -12,13 +12,12 @@ package sha512
 
 import (
 	"crypto"
+	"crypto/internal/boring"
 	"encoding/binary"
 	"errors"
 	"hash"
 )
 
-import "crypto/internal/boring"
-
 func init() {
 	crypto.RegisterHash(crypto.SHA384, New384)
 	crypto.RegisterHash(crypto.SHA512, New)
@@ -345,11 +344,7 @@ func (d *digest) checkSum() [Size]byte {
 // Sum512 returns the SHA512 checksum of the data.
 func Sum512(data []byte) [Size]byte {
 	if boring.Enabled {
-		h := New()
-		h.Write(data)
-		var ret [Size]byte
-		h.Sum(ret[:0])
-		return ret
+		return boring.SHA512(data)
 	}
 	d := digest{function: crypto.SHA512}
 	d.Reset()
@@ -360,11 +355,7 @@ func Sum512(data []byte) [Size]byte {
 // Sum384 returns the SHA384 checksum of the data.
 func Sum384(data []byte) [Size384]byte {
 	if boring.Enabled {
-		h := New384()
-		h.Write(data)
-		var ret [Size384]byte
-		h.Sum(ret[:0])
-		return ret
+		return boring.SHA384(data)
 	}
 	d := digest{function: crypto.SHA384}
 	d.Reset()