include full smtp response in dsn on errors

we now keep track of the full smtp error responses, potentially multi-line. and
we include it in a dsn in the first free-form human-readable text.

it can have multiple lines in practice, e.g. when a destination mail server
tries to be helpful in explaining what the problem is.
This commit is contained in:
Mechiel Lukkien 2024-02-14 23:37:43 +01:00
parent 39bfa4338a
commit 50c13965a7
No known key found for this signature in database
5 changed files with 116 additions and 100 deletions

View file

@ -89,14 +89,14 @@ var (
)
// todo: rename function, perhaps put some of the params in a delivery struct so we don't pass all the params all the time?
func fail(ctx context.Context, qlog mlog.Log, m Msg, backoff time.Duration, permanent bool, remoteMTA dsn.NameIP, secodeOpt, errmsg string) {
func fail(ctx context.Context, qlog mlog.Log, m Msg, backoff time.Duration, permanent bool, remoteMTA dsn.NameIP, secodeOpt, errmsg string, moreLines []string) {
// todo future: when we implement relaying, we should be able to send DSNs to non-local users. and possibly specify a null mailfrom. ../rfc/5321:1503
// todo future: when we implement relaying, and a dsn cannot be delivered, and requiretls was active, we cannot drop the message. instead deliver to local postmaster? though ../rfc/8689:383 may intend to say the dsn should be delivered without requiretls?
// todo future: when we implement smtp dsn extension, parameter RET=FULL must be disregarded for messages with REQUIRETLS. ../rfc/8689:379
if permanent || m.MaxAttempts == 0 && m.Attempts >= 8 || m.MaxAttempts > 0 && m.Attempts >= m.MaxAttempts {
qlog.Errorx("permanent failure delivering from queue", errors.New(errmsg))
deliverDSNFailure(ctx, qlog, m, remoteMTA, secodeOpt, errmsg)
deliverDSNFailure(ctx, qlog, m, remoteMTA, secodeOpt, errmsg, moreLines)
if err := queueDelete(context.Background(), m.ID); err != nil {
qlog.Errorx("deleting message from queue after permanent failure", err)
@ -116,7 +116,7 @@ func fail(ctx context.Context, qlog mlog.Log, m Msg, backoff time.Duration, perm
qlog.Errorx("temporary failure delivering from queue, sending delayed dsn", errors.New(errmsg), slog.Duration("backoff", backoff))
retryUntil := m.LastAttempt.Add((4 + 8 + 16) * time.Hour)
deliverDSNDelay(ctx, qlog, m, remoteMTA, secodeOpt, errmsg, retryUntil)
deliverDSNDelay(ctx, qlog, m, remoteMTA, secodeOpt, errmsg, moreLines, retryUntil)
} else {
qlog.Errorx("temporary failure delivering from queue", errors.New(errmsg), slog.Duration("backoff", backoff), slog.Time("nextattempt", m.NextAttempt))
}
@ -168,7 +168,7 @@ func deliverDirect(qlog mlog.Log, resolver dns.Resolver, dialer smtpclient.Diale
recipientDomainResult.Summary.TotalFailureSessionCount++
}
fail(ctx, qlog, m, backoff, permanent, dsn.NameIP{}, "", err.Error())
fail(ctx, qlog, m, backoff, permanent, dsn.NameIP{}, "", err.Error(), nil)
return
}
@ -188,7 +188,7 @@ func deliverDirect(qlog mlog.Log, resolver dns.Resolver, dialer smtpclient.Diale
} else {
qlog.Infox("mtasts lookup temporary error, aborting delivery attempt", err, slog.Any("domain", origNextHop))
recipientDomainResult.Summary.TotalFailureSessionCount++
fail(ctx, qlog, m, backoff, false, dsn.NameIP{}, "", err.Error())
fail(ctx, qlog, m, backoff, false, dsn.NameIP{}, "", err.Error(), nil)
return
}
}
@ -206,6 +206,7 @@ func deliverDirect(qlog mlog.Log, resolver dns.Resolver, dialer smtpclient.Diale
// ../rfc/3974:268.
var remoteMTA dsn.NameIP
var secodeOpt, errmsg string
var moreLines []string // For additional SMTP response lines, included in DSN.
permanent = false
nmissingRequireTLS := 0
// todo: should make distinction between host permanently not accepting the message, and the message not being deliverable permanently. e.g. a mx host may have a size limit, or not accept 8bitmime, while another host in the list does accept the message. same for smtputf8, ../rfc/6531:555
@ -230,6 +231,7 @@ func deliverDirect(qlog mlog.Log, resolver dns.Resolver, dialer smtpclient.Diale
metricTLSRequiredNoIgnored.WithLabelValues("mtastsmx").Inc()
} else {
errmsg = fmt.Sprintf("mx host %s does not match enforced mta-sts policy with hosts %s", h.Domain, strings.Join(policyHosts, ","))
moreLines = nil
qlog.Error("mx host does not match mta-sts policy in mode enforce, skipping", slog.Any("host", h.Domain), slog.Any("policyhosts", policyHosts))
recipientDomainResult.Summary.TotalFailureSessionCount++
continue
@ -269,7 +271,7 @@ func deliverDirect(qlog mlog.Log, resolver dns.Resolver, dialer smtpclient.Diale
var badTLS, ok bool
var hostResult tlsrpt.Result
permanent, tlsDANE, badTLS, secodeOpt, remoteIP, errmsg, hostResult, ok = deliverHost(nqlog, resolver, dialer, ourHostname, transportName, h, enforceMTASTS, haveMX, origNextHopAuthentic, origNextHop, expandedNextHopAuthentic, expandedNextHop, &m, tlsMode, tlsPKIX, &recipientDomainResult)
permanent, tlsDANE, badTLS, secodeOpt, remoteIP, errmsg, moreLines, hostResult, ok = deliverHost(nqlog, resolver, dialer, ourHostname, transportName, h, enforceMTASTS, haveMX, origNextHopAuthentic, origNextHop, expandedNextHopAuthentic, expandedNextHop, &m, tlsMode, tlsPKIX, &recipientDomainResult)
var zerotype tlsrpt.PolicyType
if hostResult.Policy.Type != zerotype {
@ -296,7 +298,7 @@ func deliverDirect(qlog mlog.Log, resolver dns.Resolver, dialer smtpclient.Diale
slog.Bool("enforcemtasts", enforceMTASTS),
slog.Bool("tlsdane", tlsDANE),
slog.Any("requiretls", m.RequireTLS))
permanent, _, _, secodeOpt, remoteIP, errmsg, _, ok = deliverHost(nqlog, resolver, dialer, ourHostname, transportName, h, enforceMTASTS, haveMX, origNextHopAuthentic, origNextHop, expandedNextHopAuthentic, expandedNextHop, &m, smtpclient.TLSSkip, false, &tlsrpt.Result{})
permanent, _, _, secodeOpt, remoteIP, errmsg, moreLines, _, ok = deliverHost(nqlog, resolver, dialer, ourHostname, transportName, h, enforceMTASTS, haveMX, origNextHopAuthentic, origNextHop, expandedNextHopAuthentic, expandedNextHop, &m, smtpclient.TLSSkip, false, &tlsrpt.Result{})
}
if ok {
@ -332,7 +334,7 @@ func deliverDirect(qlog mlog.Log, resolver dns.Resolver, dialer smtpclient.Diale
permanent = true
}
fail(ctx, qlog, m, backoff, permanent, remoteMTA, secodeOpt, errmsg)
fail(ctx, qlog, m, backoff, permanent, remoteMTA, secodeOpt, errmsg, moreLines)
return
}
@ -352,7 +354,7 @@ func deliverDirect(qlog mlog.Log, resolver dns.Resolver, dialer smtpclient.Diale
// The returned hostResult holds TLSRPT reporting results for the connection
// attempt. Its policy type can be the zero value, indicating there was no finding
// (e.g. internal error).
func deliverHost(log mlog.Log, resolver dns.Resolver, dialer smtpclient.Dialer, ourHostname dns.Domain, transportName string, host dns.IPDomain, enforceMTASTS, haveMX, origNextHopAuthentic bool, origNextHop dns.Domain, expandedNextHopAuthentic bool, expandedNextHop dns.Domain, m *Msg, tlsMode smtpclient.TLSMode, tlsPKIX bool, recipientDomainResult *tlsrpt.Result) (permanent, tlsDANE, badTLS bool, secodeOpt string, remoteIP net.IP, errmsg string, hostResult tlsrpt.Result, ok bool) {
func deliverHost(log mlog.Log, resolver dns.Resolver, dialer smtpclient.Dialer, ourHostname dns.Domain, transportName string, host dns.IPDomain, enforceMTASTS, haveMX, origNextHopAuthentic bool, origNextHop dns.Domain, expandedNextHopAuthentic bool, expandedNextHop dns.Domain, m *Msg, tlsMode smtpclient.TLSMode, tlsPKIX bool, recipientDomainResult *tlsrpt.Result) (permanent, tlsDANE, badTLS bool, secodeOpt string, remoteIP net.IP, errmsg string, moreLines []string, hostResult tlsrpt.Result, ok bool) {
// About attempting delivery to multiple addresses of a host: ../rfc/5321:3898
tlsRequiredNo := m.RequireTLS != nil && !*m.RequireTLS
@ -386,7 +388,7 @@ func deliverHost(log mlog.Log, resolver dns.Resolver, dialer smtpclient.Dialer,
// Open message to deliver.
f, err := os.Open(m.MessagePath())
if err != nil {
return false, false, false, "", nil, fmt.Sprintf("open message file: %s", err), hostResult, false
return false, false, false, "", nil, fmt.Sprintf("open message file: %s", err), nil, hostResult, false
}
msgr := store.FileMsgReader(m.MsgPrefix, f)
defer func() {
@ -517,7 +519,7 @@ func deliverHost(log mlog.Log, resolver dns.Resolver, dialer smtpclient.Dialer,
log.Info("verified tls is required, but destination has no usable dane records and no mta-sts policy, canceling delivery attempt to host")
metricRequireTLSUnsupported.WithLabelValues("nopolicy").Inc()
// Resond with proper enhanced status code. ../rfc/8689:301
return false, tlsDANE, false, smtp.SePol7MissingReqTLS, remoteIP, "missing required tls verification mechanism", hostResult, false
return false, tlsDANE, false, smtp.SePol7MissingReqTLS, remoteIP, "missing required tls verification mechanism", nil, hostResult, false
}
// Dial the remote host given the IPs if no error yet.
@ -545,7 +547,7 @@ func deliverHost(log mlog.Log, resolver dns.Resolver, dialer smtpclient.Dialer,
metricConnection.WithLabelValues(result).Inc()
if err != nil {
log.Debugx("connecting to remote smtp", err, slog.Any("host", host))
return false, tlsDANE, false, "", remoteIP, fmt.Sprintf("dialing smtp server: %v", err), hostResult, false
return false, tlsDANE, false, "", remoteIP, fmt.Sprintf("dialing smtp server: %v", err), nil, hostResult, false
}
var mailFrom string
@ -636,7 +638,7 @@ func deliverHost(log mlog.Log, resolver dns.Resolver, dialer smtpclient.Dialer,
deliveryResult = "error"
}
if err == nil {
return false, tlsDANE, false, "", remoteIP, "", hostResult, true
return false, tlsDANE, false, "", remoteIP, "", nil, hostResult, true
} else if cerr, ok := err.(smtpclient.Error); ok {
// If we are being rejected due to policy reasons on the first
// attempt and remote has both IPv4 and IPv6, we'll give it
@ -652,9 +654,9 @@ func deliverHost(log mlog.Log, resolver dns.Resolver, dialer smtpclient.Dialer,
secode = smtp.SePol7MissingReqTLS
metricRequireTLSUnsupported.WithLabelValues("norequiretls").Inc()
}
return permanent, tlsDANE, errors.Is(cerr, smtpclient.ErrTLS), secode, remoteIP, cerr.Error(), hostResult, false
return permanent, tlsDANE, errors.Is(cerr, smtpclient.ErrTLS), secode, remoteIP, cerr.Error(), cerr.MoreLines, hostResult, false
} else {
return false, tlsDANE, errors.Is(cerr, smtpclient.ErrTLS), "", remoteIP, err.Error(), hostResult, false
return false, tlsDANE, errors.Is(cerr, smtpclient.ErrTLS), "", remoteIP, err.Error(), nil, hostResult, false
}
}

View file

@ -6,6 +6,7 @@ import (
"fmt"
"log/slog"
"os"
"strings"
"time"
"github.com/prometheus/client_golang/prometheus"
@ -29,7 +30,7 @@ var (
)
)
func deliverDSNFailure(ctx context.Context, log mlog.Log, m Msg, remoteMTA dsn.NameIP, secodeOpt, errmsg string) {
func deliverDSNFailure(ctx context.Context, log mlog.Log, m Msg, remoteMTA dsn.NameIP, secodeOpt, errmsg string, moreLines []string) {
const subject = "mail delivery failed"
message := fmt.Sprintf(`
Delivery has failed permanently for your email to:
@ -41,12 +42,12 @@ No further deliveries will be attempted.
Error during the last delivery attempt:
%s
`, m.Recipient().XString(m.SMTPUTF8), errmsg)
`, m.Recipient().XString(m.SMTPUTF8), strings.Join(append([]string{errmsg}, moreLines...), "\n\t"))
deliverDSN(ctx, log, m, remoteMTA, secodeOpt, errmsg, true, nil, subject, message)
}
func deliverDSNDelay(ctx context.Context, log mlog.Log, m Msg, remoteMTA dsn.NameIP, secodeOpt, errmsg string, retryUntil time.Time) {
func deliverDSNDelay(ctx context.Context, log mlog.Log, m Msg, remoteMTA dsn.NameIP, secodeOpt, errmsg string, moreLines []string, retryUntil time.Time) {
// Should not happen, but doesn't hurt to prevent sending delayed delivery
// notifications for DMARC reports. We don't want to waste postmaster attention.
if m.IsDMARCReport {
@ -65,7 +66,7 @@ If these attempts all fail, you will receive a notice.
Error during the last delivery attempt:
%s
`, m.Recipient().XString(false), errmsg)
`, m.Recipient().XString(false), strings.Join(append([]string{errmsg}, moreLines...), "\n\t"))
deliverDSN(ctx, log, m, remoteMTA, secodeOpt, errmsg, false, &retryUntil, subject, message)
}

View file

@ -581,7 +581,7 @@ func deliver(log mlog.Log, resolver dns.Resolver, m Msg) {
transport, ok = mox.Conf.Static.Transports[m.Transport]
if !ok {
var remoteMTA dsn.NameIP // Zero value, will not be included in DSN. ../rfc/3464:1027
fail(ctx, qlog, m, backoff, false, remoteMTA, "", fmt.Sprintf("cannot find transport %q", m.Transport))
fail(ctx, qlog, m, backoff, false, remoteMTA, "", fmt.Sprintf("cannot find transport %q", m.Transport), nil)
return
}
transportName = m.Transport
@ -692,10 +692,10 @@ func deliver(log mlog.Log, resolver dns.Resolver, m Msg) {
if transport.Socks != nil {
socksdialer, err := proxy.SOCKS5("tcp", transport.Socks.Address, nil, &net.Dialer{})
if err != nil {
fail(ctx, qlog, m, backoff, false, dsn.NameIP{}, "", fmt.Sprintf("socks dialer: %v", err))
fail(ctx, qlog, m, backoff, false, dsn.NameIP{}, "", fmt.Sprintf("socks dialer: %v", err), nil)
return
} else if d, ok := socksdialer.(smtpclient.Dialer); !ok {
fail(ctx, qlog, m, backoff, false, dsn.NameIP{}, "", "socks dialer is not a contextdialer")
fail(ctx, qlog, m, backoff, false, dsn.NameIP{}, "", "socks dialer is not a contextdialer", nil)
return
} else {
dialer = d

View file

@ -78,7 +78,7 @@ func deliverSubmit(qlog mlog.Log, resolver dns.Resolver, dialer smtpclient.Diale
requireTLS := m.RequireTLS != nil && *m.RequireTLS
if requireTLS && (tlsMode != smtpclient.TLSRequiredStartTLS && tlsMode != smtpclient.TLSImmediate || !tlsPKIX) {
errmsg = fmt.Sprintf("transport %s: message requires verified tls but transport does not verify tls", transportName)
fail(ctx, qlog, m, backoff, true, dsn.NameIP{}, smtp.SePol7MissingReqTLS, errmsg)
fail(ctx, qlog, m, backoff, true, dsn.NameIP{}, smtp.SePol7MissingReqTLS, errmsg, nil)
return
}
@ -115,7 +115,7 @@ func deliverSubmit(qlog mlog.Log, resolver dns.Resolver, dialer smtpclient.Diale
}
qlog.Errorx("dialing for submission", err, slog.String("remote", addr))
errmsg = fmt.Sprintf("transport %s: dialing %s for submission: %v", transportName, addr, err)
fail(ctx, qlog, m, backoff, false, dsn.NameIP{}, "", errmsg)
fail(ctx, qlog, m, backoff, false, dsn.NameIP{}, "", errmsg, nil)
return
}
dialcancel()
@ -171,7 +171,7 @@ func deliverSubmit(qlog mlog.Log, resolver dns.Resolver, dialer smtpclient.Diale
qlog.Errorx("establishing smtp session for submission", err, slog.String("remote", addr))
errmsg = fmt.Sprintf("transport %s: establishing smtp session with %s for submission: %v", transportName, addr, err)
secodeOpt = smtperr.Secode
fail(ctx, qlog, m, backoff, false, remoteMTA, secodeOpt, errmsg)
fail(ctx, qlog, m, backoff, false, remoteMTA, secodeOpt, errmsg, smtperr.MoreLines)
return
}
defer func() {
@ -196,7 +196,7 @@ func deliverSubmit(qlog mlog.Log, resolver dns.Resolver, dialer smtpclient.Diale
if err != nil {
qlog.Errorx("opening message for delivery", err, slog.String("remote", addr), slog.String("path", p))
errmsg = fmt.Sprintf("transport %s: opening message file for submission: %v", transportName, err)
fail(ctx, qlog, m, backoff, false, dsn.NameIP{}, "", errmsg)
fail(ctx, qlog, m, backoff, false, dsn.NameIP{}, "", errmsg, nil)
return
}
msgr = store.FileMsgReader(m.MsgPrefix, f)
@ -239,7 +239,7 @@ func deliverSubmit(qlog mlog.Log, resolver dns.Resolver, dialer smtpclient.Diale
permanent = smtperr.Permanent
secodeOpt = smtperr.Secode
errmsg = fmt.Sprintf("transport %s: submitting email to %s: %v", transportName, addr, err)
fail(ctx, qlog, m, backoff, permanent, remoteMTA, secodeOpt, errmsg)
fail(ctx, qlog, m, backoff, permanent, remoteMTA, secodeOpt, errmsg, smtperr.MoreLines)
return
}
qlog.Info("delivered from queue with transport")

View file

@ -163,6 +163,9 @@ type Error struct {
// For errors due to SMTP responses, the full SMTP line excluding CRLF that caused
// the error. Typically the last line read.
Line string
// Optional additional lines in case of multi-line SMTP response. Most SMTP
// responses are single-line, leaving this field empty.
MoreLines []string
// Underlying error, e.g. one of the Err variables in this package, or io errors.
Err error
}
@ -418,27 +421,27 @@ func (c *Client) tlsConfig() *tls.Config {
// xbotchf generates a temporary error and marks the client as botched. e.g. for
// i/o errors or invalid protocol messages.
func (c *Client) xbotchf(code int, secode string, lastLine, format string, args ...any) {
panic(c.botchf(code, secode, lastLine, format, args...))
func (c *Client) xbotchf(code int, secode string, firstLine string, moreLines []string, format string, args ...any) {
panic(c.botchf(code, secode, firstLine, moreLines, format, args...))
}
// botchf generates a temporary error and marks the client as botched. e.g. for
// i/o errors or invalid protocol messages.
func (c *Client) botchf(code int, secode string, lastLine, format string, args ...any) error {
func (c *Client) botchf(code int, secode string, firstLine string, moreLines []string, format string, args ...any) error {
c.botched = true
return c.errorf(false, code, secode, lastLine, format, args...)
return c.errorf(false, code, secode, firstLine, moreLines, format, args...)
}
func (c *Client) errorf(permanent bool, code int, secode, lastLine, format string, args ...any) error {
func (c *Client) errorf(permanent bool, code int, secode, firstLine string, moreLines []string, format string, args ...any) error {
var cmd string
if len(c.cmds) > 0 {
cmd = c.cmds[0]
}
return Error{permanent, code, secode, cmd, lastLine, fmt.Errorf(format, args...)}
return Error{permanent, code, secode, cmd, firstLine, moreLines, fmt.Errorf(format, args...)}
}
func (c *Client) xerrorf(permanent bool, code int, secode, lastLine, format string, args ...any) {
panic(c.errorf(permanent, code, secode, lastLine, format, args...))
func (c *Client) xerrorf(permanent bool, code int, secode, firstLine string, moreLines []string, format string, args ...any) {
panic(c.errorf(permanent, code, secode, firstLine, moreLines, format, args...))
}
// timeoutWriter passes each Write on to conn after setting a write deadline on conn based on
@ -477,7 +480,7 @@ func (c *Client) readline() (string, error) {
c.tlsResultAddFailureDetails(-1, 1, c.tlsrptFailureDetails(resultType, reasonCode))
}
return line, c.botchf(0, "", "", "%s: %w", strings.Join(c.cmds, ","), err)
return line, c.botchf(0, "", "", nil, "%s: %w", strings.Join(c.cmds, ","), err)
}
c.firstReadAfterHandshake = false
return line, nil
@ -511,45 +514,55 @@ func (c *Client) xbwritelinef(format string, args ...any) {
func (c *Client) xbwriteline(line string) {
_, err := fmt.Fprintf(c.w, "%s\r\n", line)
if err != nil {
c.xbotchf(0, "", "", "write: %w", err)
c.xbotchf(0, "", "", nil, "write: %w", err)
}
}
func (c *Client) xflush() {
err := c.w.Flush()
if err != nil {
c.xbotchf(0, "", "", "writes: %w", err)
c.xbotchf(0, "", "", nil, "writes: %w", err)
}
}
// read response, possibly multiline, with supporting extended codes based on configuration in client.
func (c *Client) xread() (code int, secode, lastLine string, texts []string) {
func (c *Client) xread() (code int, secode, firstLine string, moreLines []string) {
var err error
code, secode, lastLine, texts, err = c.read()
code, secode, firstLine, moreLines, err = c.read()
if err != nil {
panic(err)
}
return
}
func (c *Client) read() (code int, secode, lastLine string, texts []string, rerr error) {
return c.readecode(c.extEcodes)
func (c *Client) read() (code int, secode, firstLine string, moreLines []string, rerr error) {
code, secode, _, firstLine, moreLines, _, rerr = c.readecode(c.extEcodes)
return
}
// read response, possibly multiline.
// if ecodes, extended codes are parsed.
func (c *Client) readecode(ecodes bool) (code int, secode, lastLine string, texts []string, rerr error) {
func (c *Client) readecode(ecodes bool) (code int, secode, lastText, firstLine string, moreLines, moreTexts []string, rerr error) {
first := true
for {
co, sec, text, line, last, err := c.read1(ecodes)
if first {
firstLine = line
first = false
} else if line != "" {
moreLines = append(moreLines, line)
if text != "" {
moreTexts = append(moreTexts, text)
}
}
if err != nil {
rerr = err
return
}
texts = append(texts, text)
if code != 0 && co != code {
// ../rfc/5321:2771
err := c.botchf(0, "", line, "%w: multiline response with different codes, previous %d, last %d", ErrProtocol, code, co)
return 0, "", "", nil, err
err := c.botchf(0, "", firstLine, moreLines, "%w: multiline response with different codes, previous %d, last %d", ErrProtocol, code, co)
return 0, "", "", "", nil, nil, err
}
code = co
if last {
@ -569,14 +582,14 @@ func (c *Client) readecode(ecodes bool) (code int, secode, lastLine string, text
slog.String("secode", sec),
slog.Duration("duration", time.Since(c.cmdStart)))
}
return co, sec, line, texts, nil
return co, sec, text, firstLine, moreLines, moreTexts, nil
}
}
}
func (c *Client) xreadecode(ecodes bool) (code int, secode, lastLine string, texts []string) {
func (c *Client) xreadecode(ecodes bool) (code int, secode, lastText, firstLine string, moreLines, moreTexts []string) {
var err error
code, secode, lastLine, texts, err = c.readecode(ecodes)
code, secode, lastText, firstLine, moreLines, moreTexts, err = c.readecode(ecodes)
if err != nil {
panic(err)
}
@ -594,12 +607,12 @@ func (c *Client) read1(ecodes bool) (code int, secode, text, line string, last b
for ; i < len(line) && line[i] >= '0' && line[i] <= '9'; i++ {
}
if i != 3 {
rerr = c.botchf(0, "", line, "%w: expected response code: %s", ErrProtocol, line)
rerr = c.botchf(0, "", line, nil, "%w: expected response code: %s", ErrProtocol, line)
return
}
v, err := strconv.ParseInt(line[:i], 10, 32)
if err != nil {
rerr = c.botchf(0, "", line, "%w: bad response code (%s): %s", ErrProtocol, err, line)
rerr = c.botchf(0, "", line, nil, "%w: bad response code (%s): %s", ErrProtocol, err, line)
return
}
code = int(v)
@ -612,7 +625,7 @@ func (c *Client) read1(ecodes bool) (code int, secode, text, line string, last b
// Allow missing space. ../rfc/5321:2570 ../rfc/5321:2612
last = true
} else {
rerr = c.botchf(0, "", line, "%w: expected space or dash after response code: %s", ErrProtocol, line)
rerr = c.botchf(0, "", line, nil, "%w: expected space or dash after response code: %s", ErrProtocol, line)
return
}
@ -684,28 +697,28 @@ func (c *Client) hello(ctx context.Context, tlsMode TLSMode, ehloHostname dns.Do
c.cmdStart = time.Now()
// Syntax: ../rfc/5321:1827
c.xwritelinef("EHLO %s", ehloHostname.ASCII)
code, _, lastLine, remains := c.xreadecode(false)
code, _, _, firstLine, moreLines, moreTexts := c.xreadecode(false)
switch code {
// ../rfc/5321:997
// ../rfc/5321:3098
case smtp.C500BadSyntax, smtp.C501BadParamSyntax, smtp.C502CmdNotImpl, smtp.C503BadCmdSeq, smtp.C504ParamNotImpl:
if !heloOK {
c.xerrorf(true, code, "", lastLine, "%w: remote claims ehlo is not supported", ErrProtocol)
c.xerrorf(true, code, "", firstLine, moreLines, "%w: remote claims ehlo is not supported", ErrProtocol)
}
// ../rfc/5321:996
c.cmds[0] = "helo"
c.cmdStart = time.Now()
c.xwritelinef("HELO %s", ehloHostname.ASCII)
code, _, lastLine, _ = c.xreadecode(false)
code, _, _, firstLine, _, _ = c.xreadecode(false)
if code != smtp.C250Completed {
c.xerrorf(code/100 == 5, code, "", lastLine, "%w: expected 250 to HELO, got %d", ErrStatus, code)
c.xerrorf(code/100 == 5, code, "", firstLine, moreLines, "%w: expected 250 to HELO, got %d", ErrStatus, code)
}
return
case smtp.C250Completed:
default:
c.xerrorf(code/100 == 5, code, "", lastLine, "%w: expected 250, got %d", ErrStatus, code)
c.xerrorf(code/100 == 5, code, "", firstLine, moreLines, "%w: expected 250, got %d", ErrStatus, code)
}
for _, s := range remains[1:] {
for _, s := range moreTexts {
// ../rfc/5321:1869
s = strings.ToUpper(strings.TrimSpace(s))
switch s {
@ -739,12 +752,12 @@ func (c *Client) hello(ctx context.Context, tlsMode TLSMode, ehloHostname dns.Do
// Read greeting.
c.cmds = []string{"(greeting)"}
c.cmdStart = time.Now()
code, _, lastLine, lines := c.xreadecode(false)
code, _, _, firstLine, moreLines, _ := c.xreadecode(false)
if code != smtp.C220ServiceReady {
c.xerrorf(code/100 == 5, code, "", lastLine, "%w: expected 220, got %d", ErrStatus, code)
c.xerrorf(code/100 == 5, code, "", firstLine, moreLines, "%w: expected 220, got %d", ErrStatus, code)
}
// ../rfc/5321:2588
c.remoteHelo, _, _ = strings.Cut(lines[0], " ")
_, c.remoteHelo, _ = strings.Cut(firstLine, " ")
// Write EHLO, falling back to HELO if server doesn't appear to support it.
hello(true)
@ -755,11 +768,11 @@ func (c *Client) hello(ctx context.Context, tlsMode TLSMode, ehloHostname dns.Do
c.cmds[0] = "starttls"
c.cmdStart = time.Now()
c.xwritelinef("STARTTLS")
code, secode, lastLine, _ := c.xread()
code, secode, firstLine, _ := c.xread()
// ../rfc/3207:107
if code != smtp.C220ServiceReady {
c.tlsResultAddFailureDetails(0, 1, c.tlsrptFailureDetails(tlsrpt.ResultSTARTTLSNotSupported, fmt.Sprintf("smtp-starttls-reply-code-%d", code)))
c.xerrorf(code/100 == 5, code, secode, lastLine, "%w: STARTTLS: got %d, expected 220", ErrTLS, code)
c.xerrorf(code/100 == 5, code, secode, firstLine, moreLines, "%w: STARTTLS: got %d, expected 220", ErrTLS, code)
}
// We don't want to do TLS on top of c.r because it also prints protocol traces: We
@ -786,7 +799,7 @@ func (c *Client) hello(ctx context.Context, tlsMode TLSMode, ehloHostname dns.Do
// multiple MX targets, we may add multiple failures, and delivery may succeed with
// a later MX target with which we can do STARTTLS. ../rfc/8460:524
c.tlsResultAdd(0, 1, err)
c.xerrorf(false, 0, "", "", "%w: STARTTLS TLS handshake: %s", ErrTLS, err)
c.xerrorf(false, 0, "", "", nil, "%w: STARTTLS TLS handshake: %s", ErrTLS, err)
}
c.firstReadAfterHandshake = true
cancel()
@ -878,9 +891,9 @@ func (c *Client) auth(auth func(mechanisms []string, cs *tls.ConnectionState) (s
}
a, err := auth(mechanisms, c.TLSConnectionState())
if err != nil {
c.xerrorf(true, 0, "", "", "get authentication mechanism: %s, server supports %s", err, strings.Join(c.extAuthMechanisms, ", "))
c.xerrorf(true, 0, "", "", nil, "get authentication mechanism: %s, server supports %s", err, strings.Join(c.extAuthMechanisms, ", "))
} else if a == nil {
c.xerrorf(true, 0, "", "", "no matching authentication mechanisms, server supports %s", strings.Join(c.extAuthMechanisms, ", "))
c.xerrorf(true, 0, "", "", nil, "no matching authentication mechanisms, server supports %s", strings.Join(c.extAuthMechanisms, ", "))
}
name, cleartextCreds := a.Info()
@ -889,16 +902,16 @@ func (c *Client) auth(auth func(mechanisms []string, cs *tls.ConnectionState) (s
c.xwriteline("*")
// Server must respond with 501. // ../rfc/4954:195
code, secode, lastline, _ := c.xread()
code, secode, firstLine, _ := c.xread()
if code != smtp.C501BadParamSyntax {
c.botched = true
}
return code, secode, lastline
return code, secode, firstLine
}
toserver, last, err := a.Next(nil)
if err != nil {
c.xerrorf(false, 0, "", "", "initial step in auth mechanism %s: %w", name, err)
c.xerrorf(false, 0, "", "", nil, "initial step in auth mechanism %s: %w", name, err)
}
if cleartextCreds {
defer c.xtrace(mlog.LevelTraceauth)()
@ -915,36 +928,36 @@ func (c *Client) auth(auth func(mechanisms []string, cs *tls.ConnectionState) (s
c.xtrace(mlog.LevelTrace) // Restore.
}
code, secode, lastLine, texts := c.xreadecode(last)
code, secode, lastText, firstLine, moreLines, _ := c.xreadecode(last)
if code == smtp.C235AuthSuccess {
if !last {
c.xerrorf(false, code, secode, lastLine, "server completed authentication earlier than client expected")
c.xerrorf(false, code, secode, firstLine, moreLines, "server completed authentication earlier than client expected")
}
return nil
} else if code == smtp.C334ContinueAuth {
if last {
c.xerrorf(false, code, secode, lastLine, "server requested unexpected continuation of authentication")
c.xerrorf(false, code, secode, firstLine, moreLines, "server requested unexpected continuation of authentication")
}
if len(texts) != 1 {
if len(moreLines) > 0 {
abort()
c.xerrorf(false, code, secode, lastLine, "server responded with multiline contination")
c.xerrorf(false, code, secode, firstLine, moreLines, "server responded with multiline contination")
}
fromserver, err := base64.StdEncoding.DecodeString(texts[0])
fromserver, err := base64.StdEncoding.DecodeString(lastText)
if err != nil {
abort()
c.xerrorf(false, code, secode, lastLine, "malformed base64 data in authentication continuation response")
c.xerrorf(false, code, secode, firstLine, moreLines, "malformed base64 data in authentication continuation response")
}
toserver, last, err = a.Next(fromserver)
if err != nil {
// For failing SCRAM, the client stops due to message about invalid proof. The
// server still sends an authentication result (it probably should send 501
// instead).
xcode, xsecode, lastline := abort()
c.xerrorf(false, xcode, xsecode, lastline, "client aborted authentication: %w", err)
xcode, xsecode, firstLine := abort()
c.xerrorf(false, xcode, xsecode, firstLine, moreLines, "client aborted authentication: %w", err)
}
c.xwriteline(base64.StdEncoding.EncodeToString(toserver))
} else {
c.xerrorf(code/100 == 5, code, secode, lastLine, "unexpected response during authentication, expected 334 continue or 235 auth success")
c.xerrorf(code/100 == 5, code, secode, firstLine, moreLines, "unexpected response during authentication, expected 334 continue or 235 auth success")
}
}
}
@ -1022,19 +1035,19 @@ func (c *Client) Deliver(ctx context.Context, mailFrom string, rcptTo string, ms
// Temporary error, e.g. OpenBSD spamd does not announce 8bitmime support, but once
// you get through, the mail server behind it probably does. Just needs a few
// retries.
c.xerrorf(false, 0, "", "", "%w", Err8bitmimeUnsupported)
c.xerrorf(false, 0, "", "", nil, "%w", Err8bitmimeUnsupported)
}
if !c.extSMTPUTF8 && reqSMTPUTF8 {
// ../rfc/6531:313
c.xerrorf(false, 0, "", "", "%w", ErrSMTPUTF8Unsupported)
c.xerrorf(false, 0, "", "", nil, "%w", ErrSMTPUTF8Unsupported)
}
if !c.extRequireTLS && requireTLS {
c.xerrorf(false, 0, "", "", "%w", ErrRequireTLSUnsupported)
c.xerrorf(false, 0, "", "", nil, "%w", ErrRequireTLSUnsupported)
}
// Max size enforced, only when not zero. ../rfc/1870:79
if c.extSize && c.maxSize > 0 && msgSize > c.maxSize {
c.xerrorf(true, 0, "", "", "%w: message is %d bytes, remote has a %d bytes maximum size", ErrSize, msgSize, c.maxSize)
c.xerrorf(true, 0, "", "", nil, "%w: message is %d bytes, remote has a %d bytes maximum size", ErrSize, msgSize, c.maxSize)
}
var mailSize, bodyType string
@ -1084,48 +1097,48 @@ func (c *Client) Deliver(ctx context.Context, mailFrom string, rcptTo string, ms
// cause a read error as it would result in an unhelpful error message and a
// temporary instead of permanent error code.
mfcode, mfsecode, mflastline, _ := c.xread()
rtcode, rtsecode, rtlastline, _, rterr := c.read()
datacode, datasecode, datalastline, _, dataerr := c.read()
mfcode, mfsecode, mffirstLine, mfmoreLines := c.xread()
rtcode, rtsecode, rtfirstLine, rtmoreLines, rterr := c.read()
datacode, datasecode, datafirstLine, datamoreLines, dataerr := c.read()
if mfcode != smtp.C250Completed {
c.xerrorf(mfcode/100 == 5, mfcode, mfsecode, mflastline, "%w: got %d, expected 2xx", ErrStatus, mfcode)
c.xerrorf(mfcode/100 == 5, mfcode, mfsecode, mffirstLine, mfmoreLines, "%w: got %d, expected 2xx", ErrStatus, mfcode)
}
if rterr != nil {
panic(rterr)
}
if rtcode != smtp.C250Completed {
c.xerrorf(rtcode/100 == 5, rtcode, rtsecode, rtlastline, "%w: got %d, expected 2xx", ErrStatus, rtcode)
c.xerrorf(rtcode/100 == 5, rtcode, rtsecode, rtfirstLine, rtmoreLines, "%w: got %d, expected 2xx", ErrStatus, rtcode)
}
if dataerr != nil {
panic(dataerr)
}
if datacode != smtp.C354Continue {
c.xerrorf(datacode/100 == 5, datacode, datasecode, datalastline, "%w: got %d, expected 354", ErrStatus, datacode)
c.xerrorf(datacode/100 == 5, datacode, datasecode, datafirstLine, datamoreLines, "%w: got %d, expected 354", ErrStatus, datacode)
}
} else {
c.cmds[0] = "mailfrom"
c.cmdStart = time.Now()
c.xwriteline(lineMailFrom)
code, secode, lastline, _ := c.xread()
code, secode, firstLine, moreLines := c.xread()
if code != smtp.C250Completed {
c.xerrorf(code/100 == 5, code, secode, lastline, "%w: got %d, expected 2xx", ErrStatus, code)
c.xerrorf(code/100 == 5, code, secode, firstLine, moreLines, "%w: got %d, expected 2xx", ErrStatus, code)
}
c.cmds[0] = "rcptto"
c.cmdStart = time.Now()
c.xwriteline(lineRcptTo)
code, secode, lastline, _ = c.xread()
code, secode, firstLine, moreLines = c.xread()
if code != smtp.C250Completed {
c.xerrorf(code/100 == 5, code, secode, lastline, "%w: got %d, expected 2xx", ErrStatus, code)
c.xerrorf(code/100 == 5, code, secode, firstLine, moreLines, "%w: got %d, expected 2xx", ErrStatus, code)
}
c.cmds[0] = "data"
c.cmdStart = time.Now()
c.xwriteline("DATA")
code, secode, lastline, _ = c.xread()
code, secode, firstLine, moreLines = c.xread()
if code != smtp.C354Continue {
c.xerrorf(code/100 == 5, code, secode, lastline, "%w: got %d, expected 354", ErrStatus, code)
c.xerrorf(code/100 == 5, code, secode, firstLine, moreLines, "%w: got %d, expected 354", ErrStatus, code)
}
}
@ -1134,13 +1147,13 @@ func (c *Client) Deliver(ctx context.Context, mailFrom string, rcptTo string, ms
defer c.xtrace(mlog.LevelTracedata)()
err := smtp.DataWrite(c.w, msg)
if err != nil {
c.xbotchf(0, "", "", "writing message as smtp data: %w", err)
c.xbotchf(0, "", "", nil, "writing message as smtp data: %w", err)
}
c.xflush()
c.xtrace(mlog.LevelTrace) // Restore.
code, secode, lastline, _ := c.xread()
code, secode, firstLine, moreLines := c.xread()
if code != smtp.C250Completed {
c.xerrorf(code/100 == 5, code, secode, lastline, "%w: got %d, expected 2xx", ErrStatus, code)
c.xerrorf(code/100 == 5, code, secode, firstLine, moreLines, "%w: got %d, expected 2xx", ErrStatus, code)
}
c.needRset = false
@ -1162,9 +1175,9 @@ func (c *Client) Reset() (rerr error) {
c.cmds[0] = "rset"
c.cmdStart = time.Now()
c.xwriteline("RSET")
code, secode, lastline, _ := c.xread()
code, secode, firstLine, moreLines := c.xread()
if code != smtp.C250Completed {
c.xerrorf(code/100 == 5, code, secode, lastline, "%w: got %d, expected 2xx", ErrStatus, code)
c.xerrorf(code/100 == 5, code, secode, firstLine, moreLines, "%w: got %d, expected 2xx", ErrStatus, code)
}
c.needRset = false
return