crypto/hmac: make Sum idempotent
Fixes #978.
R=rsc
CC=golang-dev
https://golang.org/cl/1967045
diff --git a/src/pkg/crypto/tls/prf.go b/src/pkg/crypto/tls/prf.go
index ee6cb78..b206d26 100644
--- a/src/pkg/crypto/tls/prf.go
+++ b/src/pkg/crypto/tls/prf.go
@@ -20,7 +20,7 @@
}
// pHash implements the P_hash function, as defined in RFC 4346, section 5.
-func pHash(result, secret, seed []byte, hash hash.Hash) {
+func pHash(result, secret, seed []byte, hash func() hash.Hash) {
h := hmac.New(hash, secret)
h.Write(seed)
a := h.Sum()
@@ -46,8 +46,8 @@
// pRF11 implements the TLS 1.1 pseudo-random function, as defined in RFC 4346, section 5.
func pRF11(result, secret, label, seed []byte) {
- hashSHA1 := sha1.New()
- hashMD5 := md5.New()
+ hashSHA1 := sha1.New
+ hashMD5 := md5.New
labelAndSeed := make([]byte, len(label)+len(seed))
copy(labelAndSeed, label)
