taldir

commit 808ecaa9274b8b38c0fb03a417692bbb7b9ed1c0
parent d034fde5da9851e09d3acffd015576ad9115a468
Author: Martin Schanzenbach <schanzen@gnunet.org>
Date:   Fri,  8 Aug 2025 14:06:11 +0200

hash with prefix free encoding

Diffstat:
M
pkg/taldir/command_validator.go
 | 
8
++++----
M
pkg/taldir/taldir.go
 | 
39
++++++++++++++++++++++++++++++---------
M
pkg/taldir/validator.go
 | 
2
+-

3 files changed, 35 insertions(+), 14 deletions(-)
diff --git a/pkg/taldir/command_validator.go b/pkg/taldir/command_validator.go
@@ -73,19 +73,19 @@ func (t *CommandValidator) IsAliasValid(alias string) (err error) {
 	return
 }
 
-func (t *CommandValidator) RegistrationStart(topic string, link string, message string, address string, challenge string) error {
+func (t *CommandValidator) RegistrationStart(topic string, link string, message string, address string, challenge string) (string, error) {
 	path, err := exec.LookPath(t.command)
 	if err != nil {
-		return err
+		return "", err
 	}
 	out, err := exec.Command(path, address, challenge, topic, message).Output()
 	// FIXME logger
 	fmt.Printf("Executing `%s %s %s %s %s`\n", path, address, challenge, topic, message)
 	if err != nil {
 		fmt.Printf("%s, %v\n", out, err)
-		return err
+		return "", err
 	}
-	return nil
+	return "", nil
 }
 
 func make_command_validator(cfg *TaldirConfig, name string, landingPageTpl *template.Template) CommandValidator {
diff --git a/pkg/taldir/taldir.go b/pkg/taldir/taldir.go
@@ -26,6 +26,7 @@ package taldir
 import (
 	"crypto/sha512"
 	"encoding/base64"
+	"encoding/binary"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -215,6 +216,9 @@ type Validation struct {
 
 	// The order ID associated with this validation
 	OrderID string `json:"-"`
+
+	// Name of the validator
+	ValidatorName string
 }
 
 // ErrorDetail is the detailed error payload returned from Taldir endpoints
@@ -331,7 +335,19 @@ func (t *Taldir) disseminateEntries() error {
 	return nil
 }
 
-// Hashes an identity key (e.g. sha256(<email address>)) with a salt for
+// Hashes the alias with its type in a prefix-free fashion
+// SHA512(len(atype||alias)||atype||alias)
+func hashAlias(atype string, alias string) []byte {
+	h := sha512.New()
+	b := make([]byte, 4)
+	binary.BigEndian.PutUint32(b, uint32(len(atype)+len(alias)))
+	h.Write(b)
+	h.Write([]byte(atype))
+	h.Write([]byte(alias))
+	return h.Sum(nil)
+}
+
+// Hashes an identity key (see hashAlias) with a salt for
 // Lookup and storage.
 func saltHAddress(hAddress string, salt string) string {
 	h := sha512.New()
@@ -480,10 +496,10 @@ func (t *Taldir) registerRequest(w http.ResponseWriter, r *http.Request) {
 
 	// Setup validation object. Retrieve object from DB if it already
 	// exists.
-	h := sha512.New()
-	h.Write([]byte(req.Address))
-	hAddress := util.Base32CrockfordEncode(h.Sum(nil))
+	hAddressBin := hashAlias(validator.Name(), req.Address)
+	hAddress := util.Base32CrockfordEncode(hAddressBin)
 	validation.HAddress = hAddress
+	validation.ValidatorName = validator.Name()
 	hsAddress := saltHAddress(validation.HAddress, t.Salt)
 	err = t.Db.First(&entry, "hs_address = ?", hsAddress).Error
 	// Round to the nearest multiple of a month
@@ -582,7 +598,7 @@ func (t *Taldir) registerRequest(w http.ResponseWriter, r *http.Request) {
 	topic := t.I18n.GetLocale(r).GetMessage("taldirRegTopic")
 	link := t.Host + "/register/" + url.QueryEscape(validation.HAddress) + "/" + url.QueryEscape(validation.Challenge) + "?address=" + url.QueryEscape(req.Address)
 	message := t.I18n.GetLocale(r).GetMessage("taldirRegMessage", link)
-	err = validator.RegistrationStart(topic, link, message, req.Address, validation.Challenge)
+	redirectionLink, err := validator.RegistrationStart(topic, link, message, req.Address, validation.Challenge)
 	if err != nil {
 		t.Logger.Logf(LogError, err.Error()+"\n")
 		t.Db.Delete(&validation)
@@ -591,6 +607,11 @@ func (t *Taldir) registerRequest(w http.ResponseWriter, r *http.Request) {
 	}
 	// FIXME does this persist this boolean or do we need to call Db.Save again?
 	validation.ChallengeSent = true
+	if len(redirectionLink) > 0 {
+		// This is dangerous, of course, but our validators are trusted, right?
+		http.Redirect(w, r, redirectionLink, http.StatusSeeOther)
+		return
+	}
 	w.WriteHeader(202)
 }
 
@@ -642,9 +663,9 @@ func (t *Taldir) validationPage(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	h := sha512.New()
-	h.Write([]byte(address))
-	expectedHAddress := util.Base32CrockfordEncode(h.Sum(nil))
+	// FIXME requires a prefix-free encoding
+	hAddressBin := hashAlias(validation.ValidatorName, address)
+	expectedHAddress := util.Base32CrockfordEncode(hAddressBin)
 
 	if expectedHAddress != validation.HAddress {
 		t.Logger.Logf(LogWarning, "Address does not match challenge!\n")
@@ -794,7 +815,7 @@ func (t *Taldir) methodLookupResultPage(w http.ResponseWriter, r *http.Request) 
 		http.Redirect(w, r, fmt.Sprintf("/landing/"+val.Name()+"?error=%s", emsg), http.StatusSeeOther)
 		return
 	} else {
-		hAddressBin := sha512.Sum512([]byte(r.URL.Query().Get("address")))
+		hAddressBin := hashAlias(val.Name(), r.URL.Query().Get("address"))
 		hAddress := util.Base32CrockfordEncode(hAddressBin[:])
 		hsAddress := saltHAddress(hAddress, t.Salt)
 		err = t.Db.First(&entry, "hs_address = ?", hsAddress).Error
diff --git a/pkg/taldir/validator.go b/pkg/taldir/validator.go
@@ -47,5 +47,5 @@ type Validator interface {
 	IsAliasValid(alias string) error
 
 	// Start registration
-	RegistrationStart(topic string, link string, message string, address string, challenge string) error
+	RegistrationStart(topic string, link string, message string, address string, challenge string) (string, error)
 }