prompt to update TOFU store on violations

2 files changed, 67 insertions, 11 deletions

diff --git a/actions.go b/actions.go
index 4196232..b8b3c87 100644
--- a/actions.go
+++ b/actions.go
@@ -127,13 +127,13 @@ func Reload(state *BrowserState, conf *Config) error {
 		body := io.LimitReader(bytes.NewBuffer(input), int64(len(input)))
 
 		state.Url.Fragment = ""
-		response, err = upload(state.Url.String(), body, tlsConf)
+		response, err = upload(state, state.Url.String(), body, tlsConf)
 		state.Url.Fragment = "prompt"
 		if err != nil {
 			return err
 		}
 	} else {
-		response, err = fetch(urlStr, tlsConf)
+		response, err = fetch(state, urlStr, tlsConf)
 		if err != nil {
 			return err
 		}
@@ -152,7 +152,7 @@ outer:
 
 				state.Url = response.Request.URL
 				state.Url.RawQuery = url.QueryEscape(strings.TrimRight(line, "\n"))
-				response, err = fetch(state.Url.String(), tlsConf)
+				response, err = fetch(state, state.Url.String(), tlsConf)
 				if err != nil {
 					return err
 				}
@@ -164,7 +164,7 @@ outer:
 
 				state.Url = response.Request.URL
 				state.Url.RawQuery = url.QueryEscape(strings.TrimRight(string(line), "\n"))
-				response, err = fetch(state.Url.String(), tlsConf)
+				response, err = fetch(state, state.Url.String(), tlsConf)
 				if err != nil {
 					return err
 				}
@@ -190,14 +190,58 @@ outer:
 	return HandleResource(state, conf)
 }
 
-func fetch(u string, tlsConf *tls.Config) (*sliderule.Response, error) {
+func fetch(state *BrowserState, u string, tlsConf *tls.Config) (*sliderule.Response, error) {
 	tlsConf.ClientSessionCache = nil
-	return sliderule.NewClient(tlsConf).Fetch(u)
+	response, err := sliderule.NewClient(tlsConf).Fetch(u)
+	var tofuErr *TOFUViolation
+	if errors.As(err, &tofuErr) {
+		writeError(err.Error())
+		state.Readline.SetPrompt("Trust new certificate instead (y/n)? [n] ")
+		line, err := state.Readline.Readline()
+		if err != nil {
+			return nil, err
+		}
+		if line != "y" {
+			return nil, tofuErr
+		}
+
+		tofuStore[tofuErr.domain] = tofuErr.got
+		if err := saveTofuStore(tofuStore); err != nil {
+			return nil, err
+		}
+
+		return sliderule.NewClient(tlsConf).Fetch(u)
+	} else if err != nil {
+		return nil, err
+	}
+	return response, nil
 }
 
-func upload(u string, body io.Reader, tlsConf *tls.Config) (*sliderule.Response, error) {
+func upload(state *BrowserState, u string, body io.Reader, tlsConf *tls.Config) (*sliderule.Response, error) {
 	tlsConf.ClientSessionCache = nil
-	return sliderule.NewClient(tlsConf).Upload(u, body)
+	response, err := sliderule.NewClient(tlsConf).Upload(u, body)
+	var tofuErr *TOFUViolation
+	if errors.As(err, &tofuErr) {
+		writeError(err.Error())
+		state.Readline.SetPrompt("Trust new certificate instead (y/n)? [n] ")
+		line, err := state.Readline.Readline()
+		if err != nil {
+			return nil, err
+		}
+		if line != "y" {
+			return nil, tofuErr
+		}
+
+		tofuStore[tofuErr.domain] = tofuErr.got
+		if err := saveTofuStore(tofuStore); err != nil {
+			return nil, err
+		}
+
+		return sliderule.NewClient(tlsConf).Upload(u, body)
+	} else if err != nil {
+		return nil, err
+	}
+	return response, nil
 }
 
 func externalMessage() ([]byte, error) {
diff --git a/tls.go b/tls.go
index fa25441..d4452f2 100644
--- a/tls.go
+++ b/tls.go
@@ -8,7 +8,7 @@ import (
 	"crypto/x509"
 	"crypto/x509/pkix"
 	"encoding/hex"
-	"errors"
+	"fmt"
 	"math/big"
 	"os"
 	"time"
@@ -23,7 +23,15 @@ func tlsConfig(state *BrowserState) *tls.Config {
 
 var tofuStore map[string]string
 
-var ErrTOFUViolation = errors.New("certificate for this domain has changed")
+type TOFUViolation struct {
+	domain   string
+	expected string
+	got      string
+}
+
+func (tv *TOFUViolation) Error() string {
+	return fmt.Sprintf("certificate for domain %s has changed from %s to %s", tv.domain, tv.expected, tv.got)
+}
 
 var anonymousTLS = &tls.Config{
 	InsecureSkipVerify: true,
@@ -43,7 +51,11 @@ func tofuVerify(connState tls.ConnectionState) error {
 	}
 
 	if certhash != expected {
-		return ErrTOFUViolation
+		return &TOFUViolation{
+			domain:   connState.ServerName,
+			expected: expected,
+			got:      certhash,
+		}
 	}
 	return nil
 }