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ksmithandClaude Sonnet 5
691f597597
cfg.use_tls was passed straight through as aiosmtplib's use_tls kwarg, which means implicit TLS -- encrypted from the first byte, port 465's convention. Port 587, what most providers (including the one that surfaced this: DreamHost) document as their primary submission port, needs STARTTLS instead -- a plaintext connection that upgrades in-band. Forcing implicit TLS against a STARTTLS-only port breaks the handshake outright: [SSL: WRONG_VERSION_NUMBER], a client TLS ClientHello sent to a server still expecting a plaintext SMTP greeting. The "Use TLS" checkbox still means "encrypt this connection" -- the fix infers which of the two negotiation modes to use from the port (465 -> implicit, everything else -> STARTTLS), matching the convention every mail client uses. start_tls is passed as an explicit requirement rather than left to aiosmtplib's opportunistic default, so a server that turns out not to support STARTTLS fails loudly instead of silently sending in plaintext despite the admin asking for encryption. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
84 lines
3.3 KiB
Python
84 lines
3.3 KiB
Python
import logging
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from email.message import EmailMessage
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import aiosmtplib
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from sqlalchemy.ext.asyncio import AsyncSession
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from app.crypto import decrypt
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from app.models import SmtpSettings
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from app.services.smtp_settings_service import get_smtp_settings
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logger = logging.getLogger(__name__)
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class SmtpNotConfiguredError(Exception):
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pass
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async def _deliver(cfg: SmtpSettings, to_address: str, subject: str, body: str) -> None:
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"""Raises on failure -- internal helper only. Callers decide whether to
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swallow (send_email) or surface (send_test_email) the error."""
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message = EmailMessage()
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message["From"] = cfg.from_address
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message["To"] = to_address
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message["Subject"] = subject
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message.set_content(body)
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password = decrypt(cfg.password_encrypted) if cfg.password_encrypted else None
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# "Use TLS" means "encrypt this connection", but SMTP has two genuinely
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# different ways to do that, and picking the wrong one breaks the
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# handshake outright rather than just failing to encrypt -- aiosmtplib's
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# own `use_tls` param means *implicit* TLS (encrypted from the first
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# byte, port 465's convention); attempting that against a STARTTLS-only
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# port produces exactly `[SSL: WRONG_VERSION_NUMBER]` (a client TLS
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# ClientHello sent to a server still expecting a plaintext SMTP
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# greeting). So the actual negotiation mode has to be inferred from the
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# port, matching the convention every mail client uses: 465 is implicit
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# TLS, everything else (587, 25, ...) is STARTTLS (plaintext connection,
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# then upgrade). `start_tls=True` (rather than leaving it to
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# aiosmtplib's opportunistic default) makes the requirement strict --
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# if the server doesn't actually support STARTTLS, this fails loudly
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# instead of silently sending in plaintext despite the admin asking for
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# encryption.
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use_implicit_tls = cfg.use_tls and cfg.port == 465
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require_starttls = cfg.use_tls and cfg.port != 465
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await aiosmtplib.send(
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message,
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hostname=cfg.host,
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port=cfg.port,
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username=cfg.username or None,
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password=password,
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use_tls=use_implicit_tls,
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start_tls=require_starttls,
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)
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async def send_email(db: AsyncSession, to_address: str, subject: str, body: str) -> None:
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"""Best-effort -- used by invite/notification flows. Never raises: an
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SMTP outage or missing configuration must never block an action (an
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invite, a room membership) that already succeeded in the database."""
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cfg = await get_smtp_settings(db)
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if cfg is None:
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logger.debug("SMTP not configured; skipping email to %s", to_address)
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return
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try:
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await _deliver(cfg, to_address, subject, body)
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except Exception:
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logger.warning("Failed to send email to %s", to_address, exc_info=True)
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async def send_test_email(db: AsyncSession, to_address: str) -> None:
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"""Used only by the admin 'send test email' button -- raises so the
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admin UI can show why it failed instead of a silent no-op."""
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cfg = await get_smtp_settings(db)
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if cfg is None:
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raise SmtpNotConfiguredError()
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await _deliver(
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cfg,
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to_address,
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"DS Chat test email",
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"This is a test email from DS Chat to confirm your SMTP settings are working.",
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)
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