143 lines
2.9 KiB
Go
143 lines
2.9 KiB
Go
package validator
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import (
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"fmt"
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"net"
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"net/mail"
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"strings"
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"time"
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"blitiri.com.ar/go/spf"
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"gitlab.com/etke.cc/go/trysmtp"
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"golang.org/x/net/context"
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)
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// Email checks if email is valid
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func (v *V) Email(email string, optionalSenderIP ...net.IP) bool {
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// edge case: email may be optional
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if email == "" {
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return !v.enforce.Email
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}
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address, err := mail.ParseAddress(email)
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if err != nil {
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v.log.Info("email %s invalid, reason: %v", email, err)
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return false
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}
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email = address.Address
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return v.emailChecks(email, optionalSenderIP...)
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}
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func (v *V) emailChecks(email string, optionalSenderIP ...net.IP) bool {
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maxChecks := 4
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var senderIP net.IP
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if len(optionalSenderIP) > 0 {
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senderIP = optionalSenderIP[0]
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}
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errchan := make(chan error, maxChecks)
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ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
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defer cancel()
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go v.emailSpamlist(ctx, email, errchan)
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go v.emailNoMX(ctx, email, errchan)
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go v.emailNoSPF(ctx, email, senderIP, errchan)
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go v.emailNoSMTP(ctx, email, errchan)
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var checks int
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for {
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checks++
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err := <-errchan
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if err != nil {
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v.log.Info("email %q is invalid, reason: %v", email, err)
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return false
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}
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if checks >= maxChecks {
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return true
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}
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}
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}
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func (v *V) emailSpamlist(ctx context.Context, email string, errchan chan error) {
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select {
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case <-ctx.Done():
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return
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default:
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emailb := []byte(email)
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for _, spamregex := range v.spamlist {
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if spamregex.Match(emailb) {
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errchan <- fmt.Errorf("spamlist")
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return
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}
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}
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errchan <- nil
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}
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}
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func (v *V) emailNoMX(ctx context.Context, email string, errchan chan error) {
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select {
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case <-ctx.Done():
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return
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default:
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if !v.enforce.MX {
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errchan <- nil
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return
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}
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at := strings.LastIndex(email, "@")
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domain := email[at+1:]
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if !v.MX(domain) {
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v.log.Info("email %s domain %s invalid, reason: no MX", email, domain)
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errchan <- fmt.Errorf("no MX")
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return
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}
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errchan <- nil
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}
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}
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func (v *V) emailNoSMTP(ctx context.Context, email string, errchan chan error) {
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select {
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case <-ctx.Done():
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return
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default:
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if !v.enforce.SMTP {
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errchan <- nil
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return
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}
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client, err := trysmtp.Connect(v.from, email)
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if err != nil {
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if strings.HasPrefix(err.Error(), "45") {
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v.log.Info("email %s may be invalid, reason: SMTP check (%v)", email, err)
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errchan <- nil
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return
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}
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v.log.Info("email %s invalid, reason: SMTP check (%v)", email, err)
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errchan <- fmt.Errorf("SMTP")
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return
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}
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client.Close()
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errchan <- nil
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}
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}
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func (v *V) emailNoSPF(ctx context.Context, email string, senderIP net.IP, errchan chan error) {
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select {
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case <-ctx.Done():
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return
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default:
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if !v.enforce.SPF {
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errchan <- nil
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return
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}
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result, _ := spf.CheckHostWithSender(senderIP, "", email, spf.WithTraceFunc(v.log.Info)) //nolint:errcheck // not a error
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if result == spf.Fail {
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errchan <- fmt.Errorf("SPF")
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return
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}
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errchan <- nil
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}
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}
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