From 7e6f143108cea1aa43f30c963c44f78bf56e6837 Mon Sep 17 00:00:00 2001
From: cathugger <cathugger@cock.li>
Date: Tue, 11 Dec 2018 22:56:29 +0000
Subject: [PATCH] generate compliant From headers, more tolerance to
 non-compliant From headers, other fixups

---
 .../backends/srndv2/src/srnd/frontend_http.go |  6 +++-
 contrib/backends/srndv2/src/srnd/message.go   | 23 +++++++++---
 contrib/backends/srndv2/src/srnd/nntp.go      | 35 ++++++++-----------
 contrib/backends/srndv2/src/srnd/util.go      | 13 +++++++
 4 files changed, 51 insertions(+), 26 deletions(-)

diff --git a/contrib/backends/srndv2/src/srnd/frontend_http.go b/contrib/backends/srndv2/src/srnd/frontend_http.go
index dd37673..c87798d 100644
--- a/contrib/backends/srndv2/src/srnd/frontend_http.go
+++ b/contrib/backends/srndv2/src/srnd/frontend_http.go
@@ -19,6 +19,7 @@ import (
 	"log"
 	"mime"
 	"net/http"
+	"net/mail"
 	"strings"
 	"time"
 )
@@ -829,7 +830,10 @@ func (self *httpFrontend) handle_postRequest(pr *postRequest, b bannedFunc, e er
 		msgid = genMessageID(pr.Frontend)
 	}
 
-	nntp.headers.Set("From", nntpSanitize(fmt.Sprintf("%s <poster@%s>", name, pr.Frontend)))
+	nntp.headers.Set("From", (&mail.Address{
+		Name:    name,
+		Address: "poster@" + pr.Frontend,
+	}).String())
 	nntp.headers.Set("Message-ID", msgid)
 
 	// set message
diff --git a/contrib/backends/srndv2/src/srnd/message.go b/contrib/backends/srndv2/src/srnd/message.go
index e12cebe..a0a8922 100644
--- a/contrib/backends/srndv2/src/srnd/message.go
+++ b/contrib/backends/srndv2/src/srnd/message.go
@@ -135,7 +135,7 @@ func (self *nntpArticle) Reset() {
 	self.boundary = ""
 	self.message = ""
 	if self.attachments != nil {
-		for idx, _ := range self.attachments {
+		for idx := range self.attachments {
 			self.attachments[idx].Reset()
 			self.attachments[idx] = nil
 		}
@@ -156,7 +156,10 @@ func newPlaintextArticle(message, email, subject, name, instance, message_id, ne
 	nntp := &nntpArticle{
 		headers: make(ArticleHeaders),
 	}
-	nntp.headers.Set("From", fmt.Sprintf("%s <%s>", name, email))
+	nntp.headers.Set("From", (&mail.Address{
+		Name:    name,
+		Address: email,
+	}).String())
 	nntp.headers.Set("Subject", subject)
 	if isSage(subject) {
 		nntp.headers.Set("X-Sage", "1")
@@ -296,18 +299,30 @@ func (self *nntpArticle) Newsgroup() string {
 
 func (self *nntpArticle) Name() string {
 	const defname = "Anonymous"
+
 	from := strings.TrimSpace(self.headers.Get("From", ""))
 	if from == "" {
 		return defname
 	}
+
 	a, e := mail.ParseAddress(from)
+	var name string
 	if e != nil {
-		return fmt.Sprintf("[Invalid From header: %v]", e)
+		// try older method - some nodes generate non-compliant stuff
+		if i := strings.IndexByte(from, '<'); i > 1 {
+			name = from[:i]
+		} else {
+			return "[Invalid From header]"
+		}
+	} else {
+		name = a.Name
 	}
-	name := strings.TrimSpace(a.Name)
+
+	name = safeHeader(name)
 	if name == "" {
 		return defname
 	}
+
 	return name
 }
 
diff --git a/contrib/backends/srndv2/src/srnd/nntp.go b/contrib/backends/srndv2/src/srnd/nntp.go
index 19a0e7f..2de8ca1 100644
--- a/contrib/backends/srndv2/src/srnd/nntp.go
+++ b/contrib/backends/srndv2/src/srnd/nntp.go
@@ -550,13 +550,6 @@ func (self *nntpConnection) checkMIMEHeaderNoAuth(daemon *NNTPDaemon, hdr textpr
 	return
 }
 
-var overReplacer = strings.NewReplacer("\t", " ", "\n", " ", "\r", "", "\000", "")
-
-// safeOver cleans string for OVER/XOVER output
-func safeOver(s string) string {
-	return strings.TrimSpace(overReplacer.Replace(s))
-}
-
 func (self *nntpConnection) handleLine(daemon *NNTPDaemon, code int, line string, conn *textproto.Conn) (err error) {
 	parts := strings.Split(line, " ")
 	var msgid string
@@ -922,24 +915,24 @@ func (self *nntpConnection) handleLine(daemon *NNTPDaemon, code int, line string
 							if model != nil {
 								if err == nil {
 									/*
-									The first 8 fields MUST be the following, in order:
-									     "0" or article number (see below)
-									     Subject header content
-									     From header content
-									     Date header content
-									     Message-ID header content
-									     References header content
-									     :bytes metadata item
-									     :lines metadata item
+										The first 8 fields MUST be the following, in order:
+										     "0" or article number (see below)
+										     Subject header content
+										     From header content
+										     Date header content
+										     Message-ID header content
+										     References header content
+										     :bytes metadata item
+										     :lines metadata item
 									*/
 									fmt.Fprintf(dw,
 										"%.6d\t%s\t\"%s\" <%s@%s>\t%s\t%s\t%s\r\n",
 										model.NNTPID(),
-										safeOver(model.Subject()),
-										safeOver(model.Name()), safeOver(model.Name()), safeOver(model.Frontend()),
-										safeOver(model.Date()),
-										safeOver(model.MessageID()),
-										safeOver(model.Reference()))
+										safeHeader(model.Subject()),
+										safeHeader(model.Name()), safeHeader(model.Name()), safeHeader(model.Frontend()),
+										safeHeader(model.Date()),
+										safeHeader(model.MessageID()),
+										safeHeader(model.Reference()))
 								}
 							}
 						}
diff --git a/contrib/backends/srndv2/src/srnd/util.go b/contrib/backends/srndv2/src/srnd/util.go
index 70db80d..e3c6706 100644
--- a/contrib/backends/srndv2/src/srnd/util.go
+++ b/contrib/backends/srndv2/src/srnd/util.go
@@ -26,6 +26,7 @@ import (
 	"strconv"
 	"strings"
 	"time"
+	"unicode"
 )
 
 func DelFile(fname string) {
@@ -161,6 +162,18 @@ func nntpSanitize(data string) (ret string) {
 	return ret
 }
 
+var safeHeaderReplacer = strings.NewReplacer(
+	"\t", " ",
+	"\n", string(unicode.ReplacementChar),
+	"\r", string(unicode.ReplacementChar),
+	"\000", string(unicode.ReplacementChar))
+
+// safeHeader replaces dangerous stuff from header,
+// also replaces space with tab for XOVER/OVER output
+func safeHeader(s string) string {
+	return strings.TrimSpace(safeHeaderReplacer.Replace(s))
+}
+
 type int64Sorter []int64
 
 func (self int64Sorter) Len() int {