resource/aws_iam_access_key: Add ses_smtp_password_v4 attribute (#11144)

Output from acceptance testing:

```
--- PASS: TestSesSmtpPasswordFromSecretKeySigV4 (0.00s)
--- PASS: TestSesSmtpPasswordFromSecretKeySigV2 (0.00s)
--- PASS: TestAccAWSAccessKey_basic (11.20s)
--- PASS: TestAccAWSAccessKey_encrypted (11.31s)
--- PASS: TestAccAWSAccessKey_inactive (18.44s)
```

aws/resource_aws_iam_access_key.go

@@ -43,6 +43,12 @@ func resourceAwsIamAccessKey() *schema.Resource {
 				Sensitive: true,
 			},
 			"ses_smtp_password": {
+				Type:       schema.TypeString,
+				Computed:   true,
+				Sensitive:  true,
+				Deprecated: "AWS SigV2 for SES SMTP passwords isy deprecated.\nUse 'ses_smtp_password_v4' for region-specific AWS SigV4 signed SES SMTP password instead.",
+			},
+			"ses_smtp_password_v4": {
 				Type:      schema.TypeString,
 				Computed:  true,
 				Sensitive: true,
@@ -105,12 +111,20 @@ func resourceAwsIamAccessKeyCreate(d *schema.ResourceData, meta interface{}) err
 		}
 	}
 
-	sesSMTPPassword, err := sesSmtpPasswordFromSecretKey(createResp.AccessKey.SecretAccessKey)
+	// AWS SigV2
+	sesSMTPPassword, err := sesSmtpPasswordFromSecretKeySigV2(createResp.AccessKey.SecretAccessKey)
 	if err != nil {
-		return fmt.Errorf("error getting SES SMTP Password from Secret Access Key: %s", err)
+		return fmt.Errorf("error getting SES SigV2 SMTP Password from Secret Access Key: %s", err)
 	}
 	d.Set("ses_smtp_password", sesSMTPPassword)
 
+	// AWS SigV4
+	sesSMTPPasswordV4, err := sesSmtpPasswordFromSecretKeySigV4(createResp.AccessKey.SecretAccessKey, meta.(*AWSClient).region)
+	if err != nil {
+		return fmt.Errorf("error getting SES SigV4 SMTP Password from Secret Access Key: %s", err)
+	}
+	d.Set("ses_smtp_password_v4", sesSMTPPasswordV4)
+
 	return resourceAwsIamAccessKeyReadResult(d, &iam.AccessKeyMetadata{
 		AccessKeyId: createResp.AccessKey.AccessKeyId,
 		CreateDate:  createResp.AccessKey.CreateDate,
@@ -197,7 +211,49 @@ func resourceAwsIamAccessKeyStatusUpdate(iamconn *iam.IAM, d *schema.ResourceDat
 	return nil
 }
 
-func sesSmtpPasswordFromSecretKey(key *string) (string, error) {
+func hmacSignature(key []byte, value []byte) ([]byte, error) {
+	h := hmac.New(sha256.New, key)
+	if _, err := h.Write(value); err != nil {
+		return []byte(""), err
+	}
+	return h.Sum(nil), nil
+}
+
+func sesSmtpPasswordFromSecretKeySigV4(key *string, region string) (string, error) {
+	if key == nil {
+		return "", nil
+	}
+	version := byte(0x04)
+	date := []byte("11111111")
+	service := []byte("ses")
+	terminal := []byte("aws4_request")
+	message := []byte("SendRawEmail")
+
+	rawSig, err := hmacSignature([]byte("AWS4"+*key), date)
+	if err != nil {
+		return "", err
+	}
+
+	if rawSig, err = hmacSignature(rawSig, []byte(region)); err != nil {
+		return "", err
+	}
+	if rawSig, err = hmacSignature(rawSig, service); err != nil {
+		return "", err
+	}
+	if rawSig, err = hmacSignature(rawSig, terminal); err != nil {
+		return "", err
+	}
+	if rawSig, err = hmacSignature(rawSig, message); err != nil {
+		return "", err
+	}
+
+	versionedSig := make([]byte, 0, len(rawSig)+1)
+	versionedSig = append(versionedSig, version)
+	versionedSig = append(versionedSig, rawSig...)
+	return base64.StdEncoding.EncodeToString(versionedSig), nil
+}
+
+func sesSmtpPasswordFromSecretKeySigV2(key *string) (string, error) {
 	if key == nil {
 		return "", nil
 	}

aws/resource_aws_iam_access_key_test.go

@@ -234,7 +234,30 @@ resource "aws_iam_access_key" "a_key" {
 `, rName)
 }
 
-func TestSesSmtpPasswordFromSecretKey(t *testing.T) {
+func TestSesSmtpPasswordFromSecretKeySigV4(t *testing.T) {
+	cases := []struct {
+		Region   string
+		Input    string
+		Expected string
+	}{
+		{"eu-central-1", "some+secret+key", "BMXhUYlu5Z3gSXVQORxlVa7XPaz91aGWdfHxvkOZdWZ2"},
+		{"eu-central-1", "another+secret+key", "BBbphbrQmrKMx42d1N6+C7VINYEBGI5v9VsZeTxwskfh"},
+		{"us-west-1", "some+secret+key", "BH+jbMzper5WwlwUar9E1ySBqHa9whi0GPo+sJ0mVYJj"},
+		{"us-west-1", "another+secret+key", "BKVmjjMDFk/qqw8EROW99bjCS65PF8WKvK5bSr4Y6EqF"},
+	}
+
+	for _, tc := range cases {
+		actual, err := sesSmtpPasswordFromSecretKeySigV4(&tc.Input, tc.Region)
+		if err != nil {
+			t.Fatalf("unexpected error: %s", err)
+		}
+		if actual != tc.Expected {
+			t.Fatalf("%q: expected %q, got %q", tc.Input, tc.Expected, actual)
+		}
+	}
+}
+
+func TestSesSmtpPasswordFromSecretKeySigV2(t *testing.T) {
 	cases := []struct {
 		Input    string
 		Expected string
@@ -244,7 +267,7 @@ func TestSesSmtpPasswordFromSecretKey(t *testing.T) {
 	}
 
 	for _, tc := range cases {
-		actual, err := sesSmtpPasswordFromSecretKey(&tc.Input)
+		actual, err := sesSmtpPasswordFromSecretKeySigV2(&tc.Input)
 		if err != nil {
 			t.Fatalf("unexpected error: %s", err)
 		}

website/docs/r/iam_access_key.html.markdown

@@ -48,6 +48,21 @@ output "secret" {
 }
 ```
 
+```hcl
+resource "aws_iam_user" "test" {
+  name = "test"
+  path = "/test/"
+}
+
+resource "aws_iam_access_key" "test" {
+  user             = aws_iam_user.test.name
+}
+
+output "aws_iam_smtp_password_v4" {
+  value = aws_iam_access_key.test.ses_smtp_password_v4
+}
+```
+
 ## Argument Reference
 
 The following arguments are supported:
@@ -75,6 +90,9 @@ the use of the secret key in automation.
 * `encrypted_secret` - The encrypted secret, base64 encoded, if `pgp_key` was specified.
 ~> **NOTE:** The encrypted secret may be decrypted using the command line,
    for example: `terraform output encrypted_secret | base64 --decode | keybase pgp decrypt`.
-* `ses_smtp_password` - The secret access key converted into an SES SMTP
-  password by applying [AWS's documented conversion
+* `ses_smtp_password` - **DEPRECATED** The secret access key converted into an SES SMTP
+  password by applying AWS's SigV2 conversion algorithm
+* `ses_smtp_password_v4` - The secret access key converted into an SES SMTP
+  password by applying [AWS's documented Sigv4 conversion
   algorithm](https://docs.aws.amazon.com/ses/latest/DeveloperGuide/smtp-credentials.html#smtp-credentials-convert).
+  As SigV4 is region specific, valid Provider regions are `ap-south-1`, `ap-southeast-2`, `eu-central-1`, `eu-west-1`, `us-east-1` and `us-west-2`. See current [AWS SES regions](https://docs.aws.amazon.com/general/latest/gr/rande.html#ses_region)