--- /dev/null
+/*
+tofuproxy -- flexible HTTP proxy, TLS terminator, X.509 certificates
+ manager, WARC/Gemini browser
+Copyright (C) 2021 Sergey Matveev <stargrave@stargrave.org>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, version 3 of the License.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package tofuproxy
+
+import (
+ "bytes"
+ "crypto/sha256"
+ "crypto/x509"
+ "encoding/hex"
+ "encoding/pem"
+ "fmt"
+ "log"
+ "os"
+ "os/exec"
+ "path/filepath"
+ "strings"
+ "sync"
+
+ "go.cypherpunks.ru/ucspi"
+ "go.stargrave.org/tofuproxy/caches"
+ "go.stargrave.org/tofuproxy/fifos"
+)
+
+const VerifyDialog = `
+# host err daneStatus certsTheir certsOur
+
+if {[string length $err] > 0} {
+ set tErr [text .tErr]
+ $tErr insert end $err
+ $tErr configure -wrap word -height 5
+ $tErr configure -state disabled
+ grid .tErr
+}
+
+proc certsDecode {raws} {
+ set certs [list]
+ foreach raw [split $raws] {
+ set lines [list]
+ set lineN 0
+ foreach line [split [binary decode hex $raw] "\n"] {
+ lappend lines [format "%03d %s" $lineN $line]
+ incr lineN
+ }
+ lappend certs [join $lines "\n"]
+ }
+ return $certs
+}
+
+set certsTheir [certsDecode $certsTheir]
+set certsOur [certsDecode $certsOur]
+
+tk_setPalette grey
+wm title . $host
+
+proc paginator {i delta t l certs} {
+ incr i $delta
+ if {$i == [llength $certs]} {
+ set i 0
+ } elseif {$i < 0} {
+ set i [expr {[llength $certs] - 1}]
+ }
+ $t configure -state normal
+ $t delete 1.0 end
+ $t insert end [lindex $certs $i]
+ $t configure -state disabled
+ $l configure -text "[expr {$i + 1}] / [llength $certs]"
+ return $i
+}
+
+proc addCertsWindow {name} {
+ global certs$name t$name sb$name page$name l$name
+ set t [text .t$name]
+ set sb [scrollbar .sb$name -command [list $t yview]]
+ $t configure -wrap word -yscrollcommand [list $sb set]
+ $t configure -state disabled
+ grid $t $sb -sticky nsew
+ set t$name $t
+ set sb$name $t
+
+ frame .fControl$name
+ set l$name [label .lPage$name]
+ button .bNext$name -text "Next" -command [subst {
+ set page$name \[paginator \$page$name +1 \$t$name \$l$name \$certs$name]
+ }]
+ button .bPrev$name -text "Prev" -command [subst {
+ set page$name \[paginator \$page$name -1 \$t$name \$l$name \$certs$name]
+ }]
+ grid .fControl$name
+ grid .lPage$name .bNext$name .bPrev$name -in .fControl$name
+ set page$name [paginator -1 +1 $t [set l$name] [set certs$name]]
+}
+
+addCertsWindow Their
+if {[llength $certsOur] > 0} { addCertsWindow Our }
+frame .fButtons
+set lDANE [label .lDANE]
+if {$daneStatus ne ""} {
+ array set daneColour {ok green bad red}
+ $lDANE configure -bg $daneColour($daneStatus)
+ $lDANE configure -text "DANE-EE: $daneStatus"
+}
+proc doAccept {} { exit 10 }
+proc doOnce {} { exit 11 }
+proc doReject {} { exit 12 }
+button .bAccept -text "Accept" -bg green -command doAccept
+button .bOnce -text "Once" -bg green -command doOnce
+button .bReject -text "Reject" -bg red -command doReject
+grid .fButtons
+grid .lDANE .bAccept .bOnce .bReject -in .fButtons
+grid rowconfigure . 0 -weight 1
+grid columnconfigure . 0 -weight 1
+
+bind . <KeyPress> {switch -exact %K {
+ q {exit 0} ; # reject once
+ a doAccept
+ o doOnce
+ r doReject
+ n {.bNextTheir invoke}
+ p {.bPrevTheir invoke}
+ N {.bNextOur invoke}
+ P {.bPrevOur invoke}
+}}
+`
+
+var (
+ CmdCerttool = "certtool"
+ CmdWish = "wish8.6"
+
+ Certs string
+ VerifyM sync.Mutex
+)
+
+func spkiHash(cert *x509.Certificate) string {
+ hsh := sha256.Sum256(cert.RawSubjectPublicKeyInfo)
+ return hex.EncodeToString(hsh[:])
+}
+
+type ErrRejected struct {
+ addr string
+}
+
+func (err ErrRejected) Error() string { return err.addr + " was rejected" }
+
+func certInfo(certRaw []byte) string {
+ cmd := exec.Command(CmdCerttool, "--certificate-info", "--inder")
+ cmd.Stdin = bytes.NewReader(certRaw)
+ out, err := cmd.Output()
+ if err != nil {
+ return err.Error()
+ }
+ return string(out)
+}
+
+func verifyCert(
+ host string,
+ dialErr error,
+ rawCerts [][]byte,
+ verifiedChains [][]*x509.Certificate,
+) error {
+ var certTheir *x509.Certificate
+ var err error
+ if len(verifiedChains) > 0 {
+ certTheir = verifiedChains[0][0]
+ } else {
+ certTheir, err = x509.ParseCertificate(rawCerts[0])
+ if err != nil {
+ return err
+ }
+ }
+ certTheirHash := spkiHash(certTheir)
+ VerifyM.Lock()
+ defer VerifyM.Unlock()
+ caches.AcceptedM.RLock()
+ certOurHash := caches.Accepted[host]
+ caches.AcceptedM.RUnlock()
+ if certTheirHash == certOurHash {
+ return nil
+ }
+ caches.RejectedM.RLock()
+ certOurHash = caches.Rejected[host]
+ caches.RejectedM.RUnlock()
+ if certTheirHash == certOurHash {
+ return ErrRejected{host}
+ }
+ daneExists, daneMatched := dane(host, certTheir)
+ if daneExists {
+ if daneMatched {
+ fifos.LogDANE <- fmt.Sprintf("%s\tACK", host)
+ } else {
+ fifos.LogDANE <- fmt.Sprintf("%s\tNAK", host)
+ }
+ }
+ fn := filepath.Join(Certs, host)
+ certsOur, _, err := ucspi.CertPoolFromFile(fn)
+ if err == nil || dialErr != nil || (daneExists && !daneMatched) {
+ if certsOur != nil && certTheirHash == spkiHash(certsOur[0]) {
+ caches.AcceptedM.Lock()
+ caches.Accepted[host] = certTheirHash
+ caches.AcceptedM.Unlock()
+ if bytes.Compare(certsOur[0].Raw, rawCerts[0]) != 0 {
+ fifos.LogCert <- fmt.Sprintf("Refresh\t%s\t%s", host, certTheirHash)
+ goto CertUpdate
+ }
+ return nil
+ }
+ var b bytes.Buffer
+ b.WriteString(fmt.Sprintf("set host \"%s\"\n", host))
+ if dialErr == nil {
+ b.WriteString(fmt.Sprintf("set err \"\"\n"))
+ } else {
+ b.WriteString(fmt.Sprintf("set err \"%s\"\n", dialErr.Error()))
+ }
+ var daneStatus string
+ if daneExists {
+ if daneMatched {
+ daneStatus = "ok"
+ } else {
+ daneStatus = "bad"
+ }
+ }
+ b.WriteString(fmt.Sprintf("set daneStatus \"%s\"\n", daneStatus))
+ hexCerts := make([]string, 0, len(rawCerts))
+ for _, rawCert := range rawCerts {
+ hexCerts = append(hexCerts, hex.EncodeToString([]byte(certInfo(rawCert))))
+ }
+ b.WriteString(fmt.Sprintf(
+ "set certsTheir \"%s\"\n", strings.Join(hexCerts, " "),
+ ))
+ hexCerts = make([]string, 0, len(certsOur))
+ for _, cert := range certsOur {
+ hexCerts = append(hexCerts, hex.EncodeToString([]byte(certInfo(cert.Raw))))
+ }
+ b.WriteString(fmt.Sprintf(
+ "set certsOur \"%s\"\n", strings.Join(hexCerts, " "),
+ ))
+ b.WriteString(VerifyDialog)
+ cmd := exec.Command(CmdWish)
+ // ioutil.WriteFile("/tmp/verify-dialog.tcl", b.Bytes(), 0666)
+ cmd.Stdin = &b
+ err = cmd.Run()
+ exitError, ok := err.(*exec.ExitError)
+ if !ok {
+ fifos.LogCert <- fmt.Sprintf("Reject\t%s\t%s", host, certTheirHash)
+ return ErrRejected{host}
+ }
+ switch exitError.ExitCode() {
+ case 10:
+ fifos.LogCert <- fmt.Sprintf("Accept\t%s\t%s", host, certTheirHash)
+ goto CertUpdate
+ case 11:
+ fifos.LogCert <- fmt.Sprintf("Once\t%s\t%s", host, certTheirHash)
+ caches.AcceptedM.Lock()
+ caches.Accepted[host] = certTheirHash
+ caches.AcceptedM.Unlock()
+ return nil
+ case 12:
+ caches.RejectedM.Lock()
+ caches.Rejected[host] = certTheirHash
+ caches.RejectedM.Unlock()
+ fallthrough
+ default:
+ fifos.LogCert <- fmt.Sprintf("Reject\t%s\t%s", host, certTheirHash)
+ return ErrRejected{host}
+ }
+ } else {
+ if !os.IsNotExist(err) {
+ return err
+ }
+ fifos.LogCert <- fmt.Sprintf("TOFU\t%s\t%s", host, certTheirHash)
+ }
+CertUpdate:
+ tmp, err := os.CreateTemp(Certs, "")
+ if err != nil {
+ log.Fatalln(err)
+ }
+ for _, rawCert := range rawCerts {
+ err = pem.Encode(tmp, &pem.Block{Type: "CERTIFICATE", Bytes: rawCert})
+ if err != nil {
+ log.Fatalln(err)
+ }
+ }
+ tmp.Close()
+ os.Rename(tmp.Name(), fn)
+ caches.AcceptedM.Lock()
+ caches.Accepted[host] = certTheirHash
+ caches.AcceptedM.Unlock()
+ return nil
+}