crypto/internal/fips140: zeroise integrity test temporary values

There is no point to zeroise anything here because there are no secrets,
but there is a strict FIPS 140-3 test requirement for it.

> TE05.08.02 (Levels 1, 2, 3, and 4): verify that any temporary values
> generated during the integrity test are zeroised upon completion of
> the integrity test

Change-Id: I7b0db075dae9910f8e825a22ca2caa2b4c918980
Reviewed-on: https://go-review.googlesource.com/c/go/+/636556
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Daniel McCarney <daniel@binaryparadox.net>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Roland Shoemaker <roland@golang.org>
Auto-Submit: Filippo Valsorda <filippo@golang.org>

diff --git a/src/crypto/internal/fips140/check/check.go b/src/crypto/internal/fips140/check/check.go
index 9d2e5d5cf6db68d0de6fb04c6cda45a3e5c99096..f8a5d7a41e982e7a4d334d19961181dabb603926 100644 (file)
--- a/src/crypto/internal/fips140/check/check.go
+++ b/src/crypto/internal/fips140/check/check.go
@@ -93,6 +93,13 @@ func init() {
                panic("fips140: verification mismatch")
        }
 
+       // "The temporary value(s) generated during the integrity test of the
+       // module’s software or firmware shall [05.10] be zeroised from the module
+       // upon completion of the integrity test"
+       clear(sum)
+       clear(nbuf[:])
+       h.Reset()
+
        if godebug.Value("#fips140") == "debug" {
                println("fips140: verified code+data")
        }