internal/wycheproof: add tests for hmac generation

Required updating wycheproofModVer to pull the most recent test
vectors. Tests against SHA1, SHA224, SHA256, SHA384, and SHA512
constructions but not the SHA3 variants.

Change-Id: I5b66632ac0c7106bd9b405f6636922a6383d8b9e
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/234718
Run-TryBot: Katie Hockman <katie@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Katie Hockman <katie@golang.org>

internal/wycheproof/hmac_test.go

diff --git a/internal/wycheproof/hmac_test.go b/internal/wycheproof/hmac_test.go
new file mode 100644
index 0000000..bcc56f2
--- /dev/null
+++ b/internal/wycheproof/hmac_test.go
@@ -0,0 +1,105 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package wycheproof
+
+import (
+	"crypto/hmac"
+	"testing"
+)
+
+func TestHMAC(t *testing.T) {
+	// MacTestVector
+	type MacTestVector struct {
+
+		// A brief description of the test case
+		Comment string `json:"comment,omitempty"`
+
+		// A list of flags
+		Flags []string `json:"flags,omitempty"`
+
+		// the key
+		Key string `json:"key,omitempty"`
+
+		// the plaintext
+		Msg string `json:"msg,omitempty"`
+
+		// Test result
+		Result string `json:"result,omitempty"`
+
+		// the authentication tag
+		Tag string `json:"tag,omitempty"`
+
+		// Identifier of the test case
+		TcId int `json:"tcId,omitempty"`
+	}
+
+	// MacTestGroup
+	type MacTestGroup struct {
+
+		// the keySize in bits
+		KeySize int `json:"keySize,omitempty"`
+
+		// the expected size of the tag in bits
+		TagSize int              `json:"tagSize,omitempty"`
+		Tests   []*MacTestVector `json:"tests,omitempty"`
+		Type    interface{}      `json:"type,omitempty"`
+	}
+
+	// Notes a description of the labels used in the test vectors
+	type Notes struct {
+	}
+
+	// Root
+	type Root struct {
+
+		// the primitive tested in the test file
+		Algorithm string `json:"algorithm,omitempty"`
+
+		// the version of the test vectors.
+		GeneratorVersion string `json:"generatorVersion,omitempty"`
+
+		// additional documentation
+		Header []string `json:"header,omitempty"`
+
+		// a description of the labels used in the test vectors
+		Notes *Notes `json:"notes,omitempty"`
+
+		// the number of test vectors in this test
+		NumberOfTests int             `json:"numberOfTests,omitempty"`
+		Schema        interface{}     `json:"schema,omitempty"`
+		TestGroups    []*MacTestGroup `json:"testGroups,omitempty"`
+	}
+
+	fileHashAlgs := map[string]string{
+		"hmac_sha1_test.json":   "SHA-1",
+		"hmac_sha224_test.json": "SHA-224",
+		"hmac_sha256_test.json": "SHA-256",
+		"hmac_sha384_test.json": "SHA-384",
+		"hmac_sha512_test.json": "SHA-512",
+	}
+
+	for f := range fileHashAlgs {
+		var root Root
+		readTestVector(t, f, &root)
+		for _, tg := range root.TestGroups {
+			h := parseHash(fileHashAlgs[f])
+			// Skip test vectors where the tag length does not equal the
+			// hash length, since crypto/hmac does not support generating
+			// these truncated tags.
+			if tg.TagSize/8 != h.Size() {
+				continue
+			}
+			for _, tv := range tg.Tests {
+				hm := hmac.New(h.New, decodeHex(tv.Key))
+				hm.Write(decodeHex(tv.Msg))
+				tag := hm.Sum(nil)
+				got := hmac.Equal(decodeHex(tv.Tag), tag)
+				if want := shouldPass(tv.Result, tv.Flags, nil); want != got {
+					t.Errorf("%s, tcid: %d, type: %s, comment: %q, unexpected result", f, tv.TcId, tv.Result, tv.Comment)
+				}
+			}
+		}
+	}
+}

internal/wycheproof/wycheproof_test.go

diff --git a/internal/wycheproof/wycheproof_test.go b/internal/wycheproof/wycheproof_test.go
index 49d6626..983ba5c 100644
--- a/internal/wycheproof/wycheproof_test.go
+++ b/internal/wycheproof/wycheproof_test.go
@@ -24,7 +24,7 @@
 	_ "crypto/sha512"
 )
 
-const wycheproofModVer = "v0.0.0-20191126014559-06e5e105eeb9"
+const wycheproofModVer = "v0.0.0-20191219022705-2196000605e4"
 
 var wycheproofTestVectorsDir string