terraform/internal/getproviders/package_authentication_test.go

package getproviders

import (
	"crypto/sha256"
	"encoding/base64"
	"errors"
	"fmt"
	"strings"
	"testing"

	"golang.org/x/crypto/openpgp"
)

func TestPackageAuthenticationResult(t *testing.T) {
	tests := []struct {
		result *PackageAuthenticationResult
		want   string
	}{
		{
			nil,
			"unauthenticated",
		},
		{
			&PackageAuthenticationResult{result: verifiedChecksum},
			"verified checksum",
		},
		{
			&PackageAuthenticationResult{result: officialProvider},
			"official provider",
		},
		{
			&PackageAuthenticationResult{result: partnerProvider},
			"partner provider",
		},
		{
			&PackageAuthenticationResult{result: communityProvider},
			"community provider",
		},
	}
	for _, test := range tests {
		if got := test.result.String(); got != test.want {
			t.Errorf("wrong value: got %q, want %q", got, test.want)
		}
	}
}

// mockAuthentication is an implementation of the PackageAuthentication
// interface which returns fixed values. This is used to test the combining
// logic of PackageAuthenticationAll.
type mockAuthentication struct {
	result packageAuthenticationResult
	err    error
}

func (m mockAuthentication) AuthenticatePackage(localLocation PackageLocation) (*PackageAuthenticationResult, error) {
	if m.err == nil {
		return &PackageAuthenticationResult{result: m.result}, nil
	} else {
		return nil, m.err
	}
}

var _ PackageAuthentication = (*mockAuthentication)(nil)

// If all authentications succeed, the returned result should come from the
// last authentication.
func TestPackageAuthenticationAll_success(t *testing.T) {
	result, err := PackageAuthenticationAll(
		&mockAuthentication{result: verifiedChecksum},
		&mockAuthentication{result: communityProvider},
	).AuthenticatePackage(nil)

	want := PackageAuthenticationResult{result: communityProvider}
	if result == nil || *result != want {
		t.Errorf("wrong result: want %#v, got %#v", want, result)
	}
	if err != nil {
		t.Errorf("wrong err: got %#v, want nil", err)
	}
}

// If an authentication fails, its error should be returned along with a nil
// result.
func TestPackageAuthenticationAll_failure(t *testing.T) {
	someError := errors.New("some error")
	result, err := PackageAuthenticationAll(
		&mockAuthentication{result: verifiedChecksum},
		&mockAuthentication{err: someError},
		&mockAuthentication{result: communityProvider},
	).AuthenticatePackage(nil)

	if result != nil {
		t.Errorf("wrong result: got %#v, want nil", result)
	}
	if err != someError {
		t.Errorf("wrong err: got %#v, want %#v", err, someError)
	}
}

// Archive checksum authentication requires a file fixture and a known-good
// SHA256 hash. The result should be "verified checksum".
func TestArchiveChecksumAuthentication_success(t *testing.T) {
	// Location must be a PackageLocalArchive path
	location := PackageLocalArchive("testdata/filesystem-mirror/registry.terraform.io/hashicorp/null/terraform-provider-null_2.1.0_linux_amd64.zip")

	// Known-good SHA256 hash for this archive
	wantSHA256Sum := [sha256.Size]byte{
		0x4f, 0xb3, 0x98, 0x49, 0xf2, 0xe1, 0x38, 0xeb,
		0x16, 0xa1, 0x8b, 0xa0, 0xc6, 0x82, 0x63, 0x5d,
		0x78, 0x1c, 0xb8, 0xc3, 0xb2, 0x59, 0x01, 0xdd,
		0x5a, 0x79, 0x2a, 0xde, 0x97, 0x11, 0xf5, 0x01,
	}

	auth := NewArchiveChecksumAuthentication(wantSHA256Sum)
	result, err := auth.AuthenticatePackage(location)

	wantResult := PackageAuthenticationResult{result: verifiedChecksum}
	if result == nil || *result != wantResult {
		t.Errorf("wrong result: got %#v, want %#v", result, wantResult)
	}
	if err != nil {
		t.Errorf("wrong err: got %s, want nil", err)
	}
}

// Archive checksum authentication can fail for various reasons. These test
// cases are almost exhaustive, missing only an io.Copy error which is
// difficult to induce.
func TestArchiveChecksumAuthentication_failure(t *testing.T) {
	tests := map[string]struct {
		location PackageLocation
		err      string
	}{
		"missing file": {
			PackageLocalArchive("testdata/no-package-here.zip"),
			"open testdata/no-package-here.zip: no such file or directory",
		},
		"checksum mismatch": {
			PackageLocalArchive("testdata/filesystem-mirror/registry.terraform.io/hashicorp/null/terraform-provider-null_2.1.0_linux_amd64.zip"),
			"archive has incorrect SHA-256 checksum 4fb39849f2e138eb16a18ba0c682635d781cb8c3b25901dd5a792ade9711f501 (expected 0000000000000000000000000000000000000000000000000000000000000000)",
		},
		"invalid location": {
			PackageLocalDir("testdata/filesystem-mirror/tfe.example.com/AwesomeCorp/happycloud/0.1.0-alpha.2/darwin_amd64"),
			"cannot check archive hash for non-archive location testdata/filesystem-mirror/tfe.example.com/AwesomeCorp/happycloud/0.1.0-alpha.2/darwin_amd64",
		},
	}

	for name, test := range tests {
		t.Run(name, func(t *testing.T) {
			// Zero expected checksum, either because we'll error before we
			// reach it, or we want to force a checksum mismatch
			auth := NewArchiveChecksumAuthentication([sha256.Size]byte{0})
			result, err := auth.AuthenticatePackage(test.location)

			if result != nil {
				t.Errorf("wrong result: got %#v, want nil", result)
			}
			if gotErr := err.Error(); gotErr != test.err {
				t.Errorf("wrong err: got %q, want %q", gotErr, test.err)
			}
		})
	}
}

// Matching checksum authentication takes a SHA256SUMS document, an archive
// filename, and an expected SHA256 hash. On success both return values should
// be nil.
func TestMatchingChecksumAuthentication_success(t *testing.T) {
	// Location is unused
	location := PackageLocalArchive("testdata/my-package.zip")

	// Two different checksums for other files
	wantSHA256Sum := [sha256.Size]byte{0xde, 0xca, 0xde}
	otherSHA256Sum := [sha256.Size]byte{0xc0, 0xff, 0xee}

	document := []byte(
		fmt.Sprintf(
			"%x README.txt\n%x my-package.zip\n",
			otherSHA256Sum,
			wantSHA256Sum,
		),
	)
	filename := "my-package.zip"

	auth := NewMatchingChecksumAuthentication(document, filename, wantSHA256Sum)
	result, err := auth.AuthenticatePackage(location)

	if result != nil {
		t.Errorf("wrong result: got %#v, want nil", result)
	}
	if err != nil {
		t.Errorf("wrong err: got %s, want nil", err)
	}
}

// Matching checksum authentication can fail for three reasons: no checksum
// in the document for the filename, invalid checksum value, and non-matching
// checksum value.
func TestMatchingChecksumAuthentication_failure(t *testing.T) {
	wantSHA256Sum := [sha256.Size]byte{0xde, 0xca, 0xde}
	filename := "my-package.zip"

	tests := map[string]struct {
		document []byte
		err      string
	}{
		"no checksum for filename": {
			[]byte(
				fmt.Sprintf(
					"%x README.txt",
					[sha256.Size]byte{0xbe, 0xef},
				),
			),
			`checksum list has no SHA-256 hash for "my-package.zip"`,
		},
		"invalid checksum": {
			[]byte(
				fmt.Sprintf(
					"%s README.txt\n%s my-package.zip",
					"horses",
					"chickens",
				),
			),
			`checksum list has invalid SHA256 hash "chickens": encoding/hex: invalid byte: U+0068 'h'`,
		},
		"checksum mismatch": {
			[]byte(
				fmt.Sprintf(
					"%x README.txt\n%x my-package.zip",
					[sha256.Size]byte{0xbe, 0xef},
					[sha256.Size]byte{0xc0, 0xff, 0xee},
				),
			),
			"checksum list has unexpected SHA-256 hash c0ffee0000000000000000000000000000000000000000000000000000000000 (expected decade0000000000000000000000000000000000000000000000000000000000)",
		},
	}

	for name, test := range tests {
		t.Run(name, func(t *testing.T) {
			// Location is unused
			location := PackageLocalArchive("testdata/my-package.zip")

			auth := NewMatchingChecksumAuthentication(test.document, filename, wantSHA256Sum)
			result, err := auth.AuthenticatePackage(location)

			if result != nil {
				t.Errorf("wrong result: got %#v, want nil", result)
			}
			if gotErr := err.Error(); gotErr != test.err {
				t.Errorf("wrong err: got %q, want %q", gotErr, test.err)
			}
		})
	}
}

// Signature authentication takes a checksum document, a signature, and a list
// of signing keys. If the document is signed by one of the given keys, the
// authentication is successful. The value of the result depends on the signing
// key and its trust signature.
func TestSignatureAuthentication_success(t *testing.T) {
	tests := map[string]struct {
		signature string
		keys      []SigningKey
		result    PackageAuthenticationResult
	}{
		"official provider": {
			testHashicorpSignatureGoodBase64,
			[]SigningKey{
				{
					ASCIIArmor: HashicorpPublicKey,
				},
			},
			PackageAuthenticationResult{result: officialProvider},
		},
		"partner provider": {
			testAuthorSignatureGoodBase64,
			[]SigningKey{
				{
					ASCIIArmor:     testAuthorKeyArmor,
					TrustSignature: testAuthorKeyTrustSignatureArmor,
				},
			},
			PackageAuthenticationResult{result: partnerProvider},
		},
		"community provider": {
			testAuthorSignatureGoodBase64,
			[]SigningKey{
				{
					ASCIIArmor: testAuthorKeyArmor,
				},
			},
			PackageAuthenticationResult{result: communityProvider},
		},
		"multiple signing keys": {
			testAuthorSignatureGoodBase64,
			[]SigningKey{
				{
					ASCIIArmor: HashicorpPartnersKey,
				},
				{
					ASCIIArmor: testAuthorKeyArmor,
				},
			},
			PackageAuthenticationResult{result: communityProvider},
		},
	}

	for name, test := range tests {
		t.Run(name, func(t *testing.T) {
			// Location is unused
			location := PackageLocalArchive("testdata/my-package.zip")

			signature, err := base64.StdEncoding.DecodeString(test.signature)
			if err != nil {
				t.Fatal(err)
			}

			auth := NewSignatureAuthentication([]byte(testShaSums), signature, test.keys)
			result, err := auth.AuthenticatePackage(location)

			if result == nil || *result != test.result {
				t.Errorf("wrong result: got %#v, want %#v", result, test.result)
			}
			if err != nil {
				t.Errorf("wrong err: got %s, want nil", err)
			}
		})
	}
}

// Signature authentication can fail for many reasons, most of which are due
// to OpenPGP failures from malformed keys or signatures.
func TestSignatureAuthentication_failure(t *testing.T) {
	tests := map[string]struct {
		signature string
		keys      []SigningKey
		err       string
	}{
		"invalid key": {
			testHashicorpSignatureGoodBase64,
			[]SigningKey{
				{
					ASCIIArmor: "invalid PGP armor value",
				},
			},
			"error decoding signing key: openpgp: invalid argument: no armored data found",
		},
		"invalid signature": {
			testSignatureBadBase64,
			[]SigningKey{
				{
					ASCIIArmor: testAuthorKeyArmor,
				},
			},
			"error checking signature: openpgp: invalid data: signature subpacket truncated",
		},
		"no keys match signature": {
			testAuthorSignatureGoodBase64,
			[]SigningKey{
				{
					ASCIIArmor: HashicorpPublicKey,
				},
			},
			"authentication signature from unknown issuer",
		},
		"invalid trust signature": {
			testAuthorSignatureGoodBase64,
			[]SigningKey{
				{
					ASCIIArmor:     testAuthorKeyArmor,
					TrustSignature: "invalid PGP armor value",
				},
			},
			"error decoding trust signature: EOF",
		},
		"unverified trust signature": {
			testAuthorSignatureGoodBase64,
			[]SigningKey{
				{
					ASCIIArmor:     testAuthorKeyArmor,
					TrustSignature: testOtherKeyTrustSignatureArmor,
				},
			},
			"error verifying trust signature: openpgp: invalid signature: hash tag doesn't match",
		},
	}

	for name, test := range tests {
		t.Run(name, func(t *testing.T) {
			// Location is unused
			location := PackageLocalArchive("testdata/my-package.zip")

			signature, err := base64.StdEncoding.DecodeString(test.signature)
			if err != nil {
				t.Fatal(err)
			}

			auth := NewSignatureAuthentication([]byte(testShaSums), signature, test.keys)
			result, err := auth.AuthenticatePackage(location)

			if result != nil {
				t.Errorf("wrong result: got %#v, want nil", result)
			}
			if gotErr := err.Error(); gotErr != test.err {
				t.Errorf("wrong err: got %s, want %s", gotErr, test.err)
			}
		})
	}
}

// testAuthorKeyArmor is test key ID 5BFEEC4317E746008621970637A6AB3BCF2C170A.
const testAuthorKeyArmor = `-----BEGIN PGP PUBLIC KEY BLOCK-----
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=mYqJ
-----END PGP PUBLIC KEY BLOCK-----`

// testAuthorKeyTrustSignatureArmor is a trust signature of the data in
// testAuthorKeyArmor signed with HashicorpPartnersKey.
const testAuthorKeyTrustSignatureArmor = `-----BEGIN PGP SIGNATURE-----
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=3A1s
-----END PGP SIGNATURE-----`

// testOtherKeyTrustSignatureArmor is a trust signature of another key (not the
// author key), signed with HashicorpPartnersKey.
const testOtherKeyTrustSignatureArmor = `-----BEGIN PGP SIGNATURE-----
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=aHOG
-----END PGP SIGNATURE-----`

// testShaSums is a string that represents the SHA256SUMS file downloaded
// for a release.
const testShaSums = "example shasums data"

// testAuthorSignatureGoodBase64 is a signature of testShaSums signed with
// testAuthorKeyArmor, which represents the SHA256SUMS.sig file downloaded for
// a release.
const testAuthorSignatureGoodBase64 = `iQEzBAABCAAdFiEEW/7sQxfnRgCGIZcGN6arO88s` +
	`FwoFAl5vh7gACgkQN6arO88sFwrAlQf6Al77qzjxNIj+NQNJfBGYUE5jHIgcuWOs1IPRTYUI` +
	`rHQIUU2RVrdHoAefKTKNzGde653JK/pYTflSV+6ini3/aZZnXlF6t001w3wswmakdwTr0hXx` +
	`Ez/hHYio72Gpn7+T/L+nl6dKkjeGqd/Kor5x2TY9uYB737ESmAe5T8ZlPaGMFHh0mYlNTeRq` +
	`4qIKqL6DwddBF4Ju2svn2MeNMGfE358H31mxAl2k4PPrwBTR1sFUCUOzAXVA/g9Ov5Y9ni2G` +
	`rkTahBtV9yuUUd1D+oRTTTdP0bj3A+3xxXmKTBhRuvurydPTicKuWzeILIJkcwp7Kl5UbI2N` +
	`n1ayZdaCIw/r4w==`

// testSignatureBadBase64 is an invalid signature.
const testSignatureBadBase64 = `iQEzBAABCAAdFiEEW/7sQxfnRgCGIZcGN6arO88s` +
	`4qIKqL6DwddBF4Ju2svn2MeNMGfE358H31mxAl2k4PPrwBTR1sFUCUOzAXVA/g9Ov5Y9ni2G` +
	`rkTahBtV9yuUUd1D+oRTTTdP0bj3A+3xxXmKTBhRuvurydPTicKuWzeILIJkcwp7Kl5UbI2N` +
	`n1ayZdaCIw/r4w==`

// testHashicorpSignatureGoodBase64 is a signature of testShaSums signed with
// HashicorpPublicKey, which represents the SHA256SUMS.sig file downloaded for
// an official release.
const testHashicorpSignatureGoodBase64 = `iQFLBAABCAA1FiEEkabn+F0FxlYwvvGJUYUth` +
	`zSP/EwFAl5w784XHHNlY3VyaXR5QGhhc2hpY29ycC5jb20ACgkQUYUthzSP/EyB8QgAv9ijp` +
	`kTcoFwDAs+1iEUrcW18h/2cU+bvFtdqNDiffzk7+YJ9ioxeWisPta/Z6hEyhdss2+5L1MNbo` +
	`oUBLABI+Aebfxa/uYFT2kX6r/eySmlY9kqNVpjXdemOQutS4NNZxdJL7CEbh2qIKCVuyo0ul` +
	`YrTdDH35vwVyLXImWiZLnrXcT/fXLpQGx/N8PDy6WmCeju5Y5RD7TuntB71eCaCZi7wFe1tR` +
	`qSoe9tD9A7ONB0rGuCY7BxqUj0S81hhz960YbNR9Q81WoNvF7b5SmcLJ1qJx1yvBLyqya6Su` +
	`DKjU/YYCh7bwHIYzpk1/nK/7SaTHpisekqojVsfDth4TA+jGA==`

// entityString function is used for logging the signing key.
func TestEntityString(t *testing.T) {
	var tests = []struct {
		name     string
		entity   *openpgp.Entity
		expected string
	}{
		{
			"nil",
			nil,
			"",
		},
		{
			"testAuthorKeyArmor",
			testReadArmoredEntity(t, testAuthorKeyArmor),
			"37A6AB3BCF2C170A Terraform Testing (plugin/discovery/) <terraform+testing@hashicorp.com>",
		},
		{
			"HashicorpPublicKey",
			testReadArmoredEntity(t, HashicorpPublicKey),
			"51852D87348FFC4C HashiCorp Security <security@hashicorp.com>",
		},
		{
			"HashicorpPartnersKey",
			testReadArmoredEntity(t, HashicorpPartnersKey),
			"7D72D4268E4660FC HashiCorp Security (Terraform Partner Signing) <security+terraform@hashicorp.com>",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			actual := entityString(tt.entity)
			if actual != tt.expected {
				t.Errorf("expected %s, actual %s", tt.expected, actual)
			}
		})
	}
}

func testReadArmoredEntity(t *testing.T, armor string) *openpgp.Entity {
	data := strings.NewReader(armor)

	el, err := openpgp.ReadArmoredKeyRing(data)
	if err != nil {
		t.Fatal(err)
	}

	if count := len(el); count != 1 {
		t.Fatalf("expected 1 entity, got %d", count)
	}

	return el[0]
}