IAM ユーザーのアクセスキーから Amazon SES SMTP 認証情報を生成してメール送信する

$ python --version
Python 3.12.13

{
"Version":"2012-10-17",
    "Statement": [
        {
"Effect": "Allow",
            "Action": "ses:SendRawEmail",
            "Resource": "*"
        }
    ]
}

#!/bin/bash

# Prompt user to provide following information
read -p "Enter SMTP username: " SMTPUsername
read -p "Enter SMTP password: " SMTPPassword
read -p "Sender email address: " MAILFROM
read -p "Receiver email address: " RCPT
read -p "Email subject: " SUBJECT
read -p "Message to send: " DATA

echo

# Encode SMTP username and password using base64
EncodedSMTPUsername=$(echo -n "$SMTPUsername" | openssl enc -base64)
EncodedSMTPPassword=$(echo -n "$SMTPPassword" | openssl enc -base64)

# Construct the email
Email="EHLO example.com
AUTH LOGIN
$EncodedSMTPUsername
$EncodedSMTPPassword
MAIL FROM: $MAILFROM
RCPT TO: $RCPT
DATA
From: $MAILFROM
To: $RCPT
Subject: $SUBJECT

$DATA
.
QUIT"

echo "$Email" | openssl s_client -crlf -quiet -starttls smtp -connect email-smtp.ap-northeast-1.amazonaws.com:587

$ chmod +x send-mail.sh 

#!/usr/bin/env python3

import hmac
import hashlib
import base64
import argparse

SMTP_REGIONS = [
    "ap-northeast-1",  # Asia Pacific (Tokyo)
]

# These values are required to calculate the signature. Do not change them.
DATE = "11111111"
SERVICE = "ses"
MESSAGE = "SendRawEmail"
TERMINAL = "aws4_request"
VERSION = 0x04

def sign(key, msg):
    return hmac.new(key, msg.encode("utf-8"), hashlib.sha256).digest()

def calculate_key(secret_access_key, region):
    if region not in SMTP_REGIONS:
        raise ValueError(f"The {region} Region doesn't have an SMTP endpoint.")

    signature = sign(("AWS4" + secret_access_key).encode("utf-8"), DATE)
    signature = sign(signature, region)
    signature = sign(signature, SERVICE)
    signature = sign(signature, TERMINAL)
    signature = sign(signature, MESSAGE)
    signature_and_version = bytes([VERSION]) + signature
    smtp_password = base64.b64encode(signature_and_version)
    return smtp_password.decode("utf-8")

def main():
    parser = argparse.ArgumentParser(
        description="Convert a Secret Access Key to an SMTP password."
    )
    parser.add_argument("secret", help="The Secret Access Key to convert.")
    parser.add_argument(
        "region",
        help="The AWS Region where the SMTP password will be used.",
        choices=SMTP_REGIONS,
    )
    args = parser.parse_args()
    print(calculate_key(args.secret, args.region))

if __name__ == "__main__":
    main()

$ python ~/smtp_credentials_generate.py <AWS_SECRET_ACCESS_KEY> ap-northeast-1
<SMTP_PASSWORD>

$ ./send-mail.sh
Enter SMTP username: AKIA****************
Enter SMTP password: <SMTP_PASSWORD>
Sender email address: sender@example.com
Receiver email address: recipient@example.net
Email subject: test-mail
Message to send: test

Connecting to <SES_SMTP_ENDPOINT_IP>
depth=2 C=US, O=Amazon, CN=Amazon Root CA 1
verify return:1
depth=1 C=US, O=Amazon, CN=Amazon RSA 2048 M01
verify return:1
depth=0 CN=email-smtp.ap-northeast-1.amazonaws.com
verify return:1
250 Ok
250-email-smtp.amazonaws.com
250-8BITMIME
250-AUTH PLAIN LOGIN
250 Ok
334 VXNlcm5hbWU6
334 UGFzc3dvcmQ6
235 Authentication successful.
250 Ok
250 Ok
354 End data with <CR><LF>.<CR><LF>
250 Ok <SES_MESSAGE_ID>

$ ./send-mail.sh
Enter SMTP username: AKIA****************
Enter SMTP password: <AWS_SECRET_ACCESS_KEY>
Sender email address: sender@example.com
Receiver email address: recipient@example.net
Email subject: test-mail
Message to send: test

535 Authentication Credentials Invalid