mirror of https://github.com/ergochat/ergo.git
126 lines
3.1 KiB
Go
126 lines
3.1 KiB
Go
// Copyright (c) 2020 Shivaram Lingamneni
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// released under the MIT license
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package email
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import (
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"errors"
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"fmt"
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"net"
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"regexp"
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"strings"
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"github.com/ergochat/ergo/irc/smtp"
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)
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var (
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ErrBlacklistedAddress = errors.New("Email address is blacklisted")
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ErrInvalidAddress = errors.New("Email address is blacklisted")
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ErrNoMXRecord = errors.New("Couldn't resolve MX record")
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)
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type MTAConfig struct {
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Server string
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Port int
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Username string
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Password string
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}
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type MailtoConfig struct {
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// legacy config format assumed the use of an MTA/smarthost,
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// so server, port, etc. appear directly at top level
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// XXX: see https://github.com/go-yaml/yaml/issues/63
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MTAConfig `yaml:",inline"`
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Enabled bool
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Sender string
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HeloDomain string `yaml:"helo-domain"`
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RequireTLS bool `yaml:"require-tls"`
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VerifyMessageSubject string `yaml:"verify-message-subject"`
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DKIM DKIMConfig
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MTAReal MTAConfig `yaml:"mta"`
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BlacklistRegexes []string `yaml:"blacklist-regexes"`
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blacklistRegexes []*regexp.Regexp
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}
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func (config *MailtoConfig) Postprocess(heloDomain string) (err error) {
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if config.Sender == "" {
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return errors.New("Invalid mailto sender address")
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}
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// check for MTA config fields at top level,
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// copy to MTAReal if present
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if config.Server != "" && config.MTAReal.Server == "" {
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config.MTAReal = config.MTAConfig
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}
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if config.HeloDomain == "" {
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config.HeloDomain = heloDomain
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}
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for _, reg := range config.BlacklistRegexes {
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compiled, err := regexp.Compile(fmt.Sprintf("^%s$", reg))
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if err != nil {
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return err
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}
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config.blacklistRegexes = append(config.blacklistRegexes, compiled)
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}
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if config.MTAConfig.Server != "" {
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// smarthost, nothing more to validate
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return nil
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}
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return config.DKIM.Postprocess()
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}
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// get the preferred MX record hostname, "" on error
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func lookupMX(domain string) (server string) {
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var minPref uint16
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results, err := net.LookupMX(domain)
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if err != nil {
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return
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}
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for _, result := range results {
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if minPref == 0 || result.Pref < minPref {
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server, minPref = result.Host, result.Pref
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}
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}
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return
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}
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func SendMail(config MailtoConfig, recipient string, msg []byte) (err error) {
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for _, reg := range config.blacklistRegexes {
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if reg.MatchString(recipient) {
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return ErrBlacklistedAddress
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}
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}
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if config.DKIM.Domain != "" {
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msg, err = DKIMSign(msg, config.DKIM)
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if err != nil {
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return
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}
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}
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var addr string
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var auth smtp.Auth
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if config.MTAReal.Server != "" {
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addr = fmt.Sprintf("%s:%d", config.MTAReal.Server, config.MTAReal.Port)
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if config.MTAReal.Username != "" && config.MTAReal.Password != "" {
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auth = smtp.PlainAuth("", config.MTAReal.Username, config.MTAReal.Password, config.MTAReal.Server)
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}
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} else {
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idx := strings.IndexByte(recipient, '@')
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if idx == -1 {
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return ErrInvalidAddress
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}
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mx := lookupMX(recipient[idx+1:])
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if mx == "" {
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return ErrNoMXRecord
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}
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addr = fmt.Sprintf("%s:smtp", mx)
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}
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return smtp.SendMail(addr, auth, config.HeloDomain, config.Sender, []string{recipient}, msg, config.RequireTLS)
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}
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