VERSION                     |  2 +-
 doc/building.texi           | 12 ++++++------
 doc/download.texi           |  4 ++++
 doc/integrity.texi          |  4 ++--
 doc/news.ru.texi            | 20 ++++++++++++++++++++
 doc/news.texi               | 18 ++++++++++++++++++
 makedist.sh                 |  2 +-
 ports/nncp/Makefile         |  2 +-
 src/cmd/nncp-bundle/main.go |  3 +++
 src/cmd/nncp-cfgnew/main.go |  4 ++--
 src/cmd/nncp-reass/main.go  |  3 +++
 src/cmd/nncp-xfer/main.go   |  5 +++++
 src/humanizer.go            | 25 ++++++++++++++++++++++++-
 src/sp.go                   | 22 +++++++++++++++++-----
 src/tmp.go                  | 18 +++++++++++++++++-
 src/toss.go                 |  4 ++++

diff --git a/VERSION b/VERSION
index 05e2d1d765d5f1e08f762bed62ec68e741252932278b059d74dd571e480ce227..9871b3c67fa0b9d06b62dc407cd355e0a52c7e10ff11d9c8b206bc1cddb05392 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-5.1.1
+5.1.2
diff --git a/doc/building.texi b/doc/building.texi
index ab4c0aa94c52dcbe151d5ddb1873d9e293981776f4d88464611570058a056b34..091105605015347b3e9752aad2cd609a681fb3ab61b406ca6f691a5d4f1f00cf 100644
--- a/doc/building.texi
+++ b/doc/building.texi
@@ -11,16 +11,16 @@     @verb{|apt install golang|}
 @end table
 
 @verbatim
-$ [fetch|wget] http://www.nncpgo.org/download/nncp-5.1.1.tar.xz
-$ [fetch|wget] http://www.nncpgo.org/download/nncp-5.1.1.tar.xz.sig
-$ gpg --verify nncp-5.1.1.tar.xz.sig nncp-5.1.1.tar.xz
-$ xz --decompress --stdout nncp-5.1.1.tar.xz | tar xf -
-$ make -C nncp-5.1.1 all
+$ [fetch|wget] http://www.nncpgo.org/download/nncp-5.1.2.tar.xz
+$ [fetch|wget] http://www.nncpgo.org/download/nncp-5.1.2.tar.xz.sig
+$ gpg --verify nncp-5.1.2.tar.xz.sig nncp-5.1.2.tar.xz
+$ xz --decompress --stdout nncp-5.1.2.tar.xz | tar xf -
+$ make -C nncp-5.1.2 all
 @end verbatim
 
 There is @command{install} make-target respecting @env{DESTDIR}. It will
 install binaries and info-documentation:
 
 @verbatim
-# make -C nncp-5.1.1 install PREFIX=/usr/local
+# make -C nncp-5.1.2 install PREFIX=/usr/local
 @end verbatim
diff --git a/doc/download.texi b/doc/download.texi
index 8ecb0b7b831a5adabc917b8acbd1c0b8af76444aef092880d5e1e71798041356..ea4e122f703d4ad9ab0639a5827aece8cbc143bdb3f2de5bf36ab5e826dc1691 100644
--- a/doc/download.texi
+++ b/doc/download.texi
@@ -23,6 +23,10 @@
 @multitable {XXXXX} {XXXX-XX-XX} {XXXX KiB} {link sign} {xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx}
 @headitem Version @tab Date @tab Size @tab Tarball @tab SHA256 checksum
 
+@item @ref{Release 5.1.1, 5.1.1} @tab 2019-12-01 @tab 1103 KiB
+@tab @url{download/nncp-5.1.1.tar.xz, link} @url{download/nncp-5.1.1.tar.xz.sig, sign}
+@tab @code{B9537678 E5B549BA 6FA0D20D 41B2D4A9 4ED31F2C AB9FAF63 A388D95E 7662A93F}
+
 @item @ref{Release 5.1.0, 5.1.0} @tab 2019-11-24 @tab 1103 KiB
 @tab @url{download/nncp-5.1.0.tar.xz, link} @url{download/nncp-5.1.0.tar.xz.sig, sign}
 @tab @code{6F5B74EC 952EAFEC 2A787463 CE1E808E CC990F03 D46F28E9 A89BAB55 5A2C2214}
diff --git a/doc/integrity.texi b/doc/integrity.texi
index ccba0ac33bcc7bed198fcc1574e91629b4f60a77f75376efb523c51692d358e4..5458e3f57837f74e64c07d1c7c739ef7287a702e58abfb57b9423a5c029c88cd 100644
--- a/doc/integrity.texi
+++ b/doc/integrity.texi
@@ -4,7 +4,7 @@
 You @strong{have to} check downloaded archives integrity and verify
 their signature to be sure that you have got trusted, untampered
 software. For integrity and authentication of downloaded binaries
-@url{https://www.gnupg.org/, The GNU Privacy Guard} is used. You must
+@url{https://www.gnupg.org/, GNU Privacy Guard} is used. You must
 download signature (@file{.sig}) provided with the tarball.
 
 For the very first time you need to import signing public key. It is
@@ -31,5 +31,5 @@ @end itemize
 
 Then you could verify tarballs signature:
 @verbatim
-$ gpg --verify nncp-5.1.1.tar.xz.sig nncp-5.1.1.tar.xz
+$ gpg --verify nncp-5.1.2.tar.xz.sig nncp-5.1.2.tar.xz
 @end verbatim
diff --git a/doc/news.ru.texi b/doc/news.ru.texi
index 70f067b3c9b849fbf4f88aee66f579cbbaf811f538604aa228314798321a0dbe..e0b0dadb5a52c123c908b39c713528a5bb33f3bd14fe849f8a396aea5762f76d 100644
--- a/doc/news.ru.texi
+++ b/doc/news.ru.texi
@@ -1,6 +1,26 @@
 @node Новости
 @section Новости
 
+@node Релиз 5.1.2
+@subsection Релиз 5.1.2
+@itemize
+
+@item
+Исправлена @strong{критичная} уязвимость: аутентификация online нод
+могла приводить к некорректной идентификации удалённой стороны, позволяя
+скачивать чужие зашифрованные пакеты.
+
+@item
+Исправлена ошибка: в новосозданных конфигурационных файлах, приватный
+публичный ключ Noise были поменяны местами, что приводило к
+невозможности online аутентификации нод.
+
+@item
+Явная синхронизация (fsync) директорий для гарантированного
+переименования файлов.
+
+@end itemize
+
 @node Релиз 5.1.1
 @subsection Релиз 5.1.1
 @itemize
diff --git a/doc/news.texi b/doc/news.texi
index 8baca54eecb26b06988f7e6c15d83db2faaa4afe5190df85cb434fbe071bb662..052be070bc6b436b9dc76bbfed42c85b47a35d8e3376452f163df7096dfd6c3b 100644
--- a/doc/news.texi
+++ b/doc/news.texi
@@ -3,6 +3,24 @@ @unnumbered News
 
 See also this page @ref{Новости, on russian}.
 
+@node Release 5.1.2
+@section Release 5.1.2
+@itemize
+
+@item
+@strong{Critical} vulnerability: remote peers authentication could lead
+to incorrect identification of remote side, allowing foreign encrypted
+packets downloading.
+
+@item
+Bugfix: private and public Noise keys were swapped in newly created
+configuration files, that lead to inability to authenticate online peers.
+
+@item
+Explicit directories fsync-ing for guaranteed files renaming.
+
+@end itemize
+
 @node Release 5.1.1
 @section Release 5.1.1
 @itemize
diff --git a/makedist.sh b/makedist.sh
index 6ea75c23101225ca596a5a1edb2914003646e86c2554d502a007b132492e786c..52004652c0156038657ed22783778843c065da29e87cf5d30b32ed521c495ee7 100755
--- a/makedist.sh
+++ b/makedist.sh
@@ -10,7 +10,7 @@ cd $tmp/nncp-$release
 git checkout v$release
 rm -fr .git
 
-mod_name=go.cypherpunks.ru/nncp/v5
+mod_name=$(sed -n 's/^module //p' src/go.mod)
 mv src src.orig
 mkdir -p src/$mod_name
 mv src.orig/* src/$mod_name
diff --git a/ports/nncp/Makefile b/ports/nncp/Makefile
index c6948ca6cb8030e477d88772ddef9a29a4eb7a95034b4ba3abbf0186acc31e35..b248e505dc5ca7a4211d9a9e5e83ee008a6114752d6d94bdea8010b9369ea054 100644
--- a/ports/nncp/Makefile
+++ b/ports/nncp/Makefile
@@ -1,7 +1,7 @@
 # $FreeBSD: head/net/nncp/Makefile 517819 2019-11-17 11:51:56Z dmgk $
 
 PORTNAME=	nncp
-DISTVERSION=	5.1.1
+DISTVERSION=	5.1.2
 CATEGORIES=	net
 MASTER_SITES=	http://www.nncpgo.org/download/
 
diff --git a/src/cmd/nncp-bundle/main.go b/src/cmd/nncp-bundle/main.go
index 342b949983604c15998168153691add6b56a78437938b10e1ac7d9b2f0d8bf5c..832c8b328e8233736a43c9ce3957de4ccc337cbd448c51ab17f95d2ee802ad35 100644
--- a/src/cmd/nncp-bundle/main.go
+++ b/src/cmd/nncp-bundle/main.go
@@ -378,6 +378,9 @@ 					}
 					if err = os.Rename(tmp.Name(), dstPath); err != nil {
 						log.Fatalln("Error during renaming:", err)
 					}
+					if err = nncp.DirSync(selfPath); err != nil {
+						log.Fatalln("Error during syncing:", err)
+					}
 				}
 			}
 			ctx.LogI("nncp-bundle", nncp.SdsAdd(sds, nncp.SDS{
diff --git a/src/cmd/nncp-cfgnew/main.go b/src/cmd/nncp-cfgnew/main.go
index 7a5f3c627c2b958a44e46b8a880420e1f92084f891c187bfc7a713236dfc7656..6c4cf7a0df4d74e311658caba6843874a47ef947ac790543774ead66b288301a 100644
--- a/src/cmd/nncp-cfgnew/main.go
+++ b/src/cmd/nncp-cfgnew/main.go
@@ -86,8 +86,8 @@ 			nncp.ToBase32(nodeOur.ExchPub[:]),
 			nncp.ToBase32(nodeOur.ExchPrv[:]),
 			nncp.ToBase32(nodeOur.SignPub[:]),
 			nncp.ToBase32(nodeOur.SignPrv[:]),
-			nncp.ToBase32(nodeOur.NoisePub[:]),
 			nncp.ToBase32(nodeOur.NoisePrv[:]),
+			nncp.ToBase32(nodeOur.NoisePub[:]),
 			nodeOur.Id.String(),
 			nncp.ToBase32(nodeOur.ExchPub[:]),
 			nncp.ToBase32(nodeOur.SignPub[:]),
@@ -220,8 +220,8 @@ 			nncp.ToBase32(nodeOur.ExchPub[:]),
 			nncp.ToBase32(nodeOur.ExchPrv[:]),
 			nncp.ToBase32(nodeOur.SignPub[:]),
 			nncp.ToBase32(nodeOur.SignPrv[:]),
-			nncp.ToBase32(nodeOur.NoisePub[:]),
 			nncp.ToBase32(nodeOur.NoisePrv[:]),
+			nncp.ToBase32(nodeOur.NoisePub[:]),
 			nodeOur.Id.String(),
 			nncp.ToBase32(nodeOur.ExchPub[:]),
 			nncp.ToBase32(nodeOur.SignPub[:]),
diff --git a/src/cmd/nncp-reass/main.go b/src/cmd/nncp-reass/main.go
index 14a98b9f0398c6d0bac513c3017dbb32f1b5cefaf9b10a020273440d43c01b99..515424fa6ab7e5f3609dd26e88323a62b65db43dca65ed5104cf1fa4ff879f05 100644
--- a/src/cmd/nncp-reass/main.go
+++ b/src/cmd/nncp-reass/main.go
@@ -238,6 +238,9 @@ 	}
 	if err = os.Rename(tmp.Name(), dstPath); err != nil {
 		log.Fatalln(err)
 	}
+	if err = nncp.DirSync(mainDir); err != nil {
+		log.Fatalln(err)
+	}
 	ctx.LogI("nncp-reass", nncp.SDS{"path": path}, "done")
 	return !hasErrors
 }
diff --git a/src/cmd/nncp-xfer/main.go b/src/cmd/nncp-xfer/main.go
index 6de52b8dcc6e7a5fdd9fb526fb16b6e1d3e09e18e6486d5f1312d151aa725885..1858ebff9e587d4d8708fead86df93b319df8267fa3497737ae6953f9cf8459c 100644
--- a/src/cmd/nncp-xfer/main.go
+++ b/src/cmd/nncp-xfer/main.go
@@ -330,6 +330,11 @@ 				ctx.LogE("nncp-xfer", nncp.SdsAdd(sds, nncp.SDS{"err": err}), "rename")
 				isBad = true
 				continue
 			}
+			if err = nncp.DirSync(dstPath); err != nil {
+				ctx.LogE("nncp-xfer", nncp.SdsAdd(sds, nncp.SDS{"err": err}), "sync")
+				isBad = true
+				continue
+			}
 			os.Remove(filepath.Join(dstPath, pktName+".part"))
 			delete(sds, "tmp")
 			ctx.LogI("nncp-xfer", nncp.SdsAdd(sds, nncp.SDS{
diff --git a/src/humanizer.go b/src/humanizer.go
index ac94e70c683043b0c7d53fc96460e0d49a3dfb854674494581948fde7e1cdb51..7dc2778a8ec53c33d5970dc64c13a77a6984368250aabf51d878752902df5c1f 100644
--- a/src/humanizer.go
+++ b/src/humanizer.go
@@ -173,7 +173,10 @@ 		}
 	case "nncp-rm":
 		msg += "removing " + sds["file"]
 	case "call-start":
-		msg = fmt.Sprintf("Connected to %s", nodeS)
+		msg = fmt.Sprintf("Connection to %s", nodeS)
+		if err, exists := sds["err"]; exists {
+			msg += ": " + err
+		}
 	case "call-finish":
 		rx, err := strconv.ParseUint(sds["rxbytes"], 10, 64)
 		if err != nil {
@@ -197,6 +200,26 @@ 			nodeS,
 			humanize.IBytes(uint64(rx)), humanize.IBytes(uint64(rxs)),
 			humanize.IBytes(uint64(tx)), humanize.IBytes(uint64(txs)),
 		)
+	case "sp-start":
+		if nodeS == "" {
+			msg += "SP"
+			if peer, exists := sds["peer"]; exists {
+				msg += fmt.Sprintf(": %s", peer)
+			}
+		} else {
+			nice, err := NicenessParse(sds["nice"])
+			if err != nil {
+				return s
+			}
+			msg += fmt.Sprintf("SP with %s (nice %s)", nodeS, NicenessFmt(nice))
+		}
+		if len(rem) > 0 {
+			msg += ": " + rem
+		}
+		if err, exists := sds["err"]; exists {
+			msg += ": " + err
+		}
+
 	case "sp-info":
 		nice, err := NicenessParse(sds["nice"])
 		if err != nil {
diff --git a/src/sp.go b/src/sp.go
index b901a24a679105c9c36fcba976457c3034deb6ec126d5a9cf6e8151775a29ce6..51a1fafbc37b7f9ba25b77681d92f0ecc99ccc3b305c240bf4f72f265a253558 100644
--- a/src/sp.go
+++ b/src/sp.go
@@ -231,6 +231,10 @@ func (state *SPState) ReadSP(src io.Reader) ([]byte, error) {
 	var sp SPRaw
 	n, err := xdr.UnmarshalLimited(src, &sp, 1<<17)
 	if err != nil {
+		ue := err.(*xdr.UnmarshalError)
+		if ue.Err == io.EOF {
+			return nil, ue.Err
+		}
 		return nil, err
 	}
 	state.RxLastSeen = time.Now()
@@ -415,8 +419,9 @@ 		return err
 	}
 
 	var node *Node
-	for _, node = range state.Ctx.Neigh {
-		if subtle.ConstantTimeCompare(state.hs.PeerStatic(), node.NoisePub[:]) == 1 {
+	for _, n := range state.Ctx.Neigh {
+		if subtle.ConstantTimeCompare(state.hs.PeerStatic(), n.NoisePub[:]) == 1 {
+			node = n
 			break
 		}
 	}
@@ -838,12 +843,12 @@ 			}
 			sdsp["xx"] = string(TRx)
 			sdsp["hash"] = ToBase32(file.Hash[:])
 			sdsp["size"] = strconv.Itoa(len(file.Payload))
-			filePath := filepath.Join(
+			dirToSync := filepath.Join(
 				state.Ctx.Spool,
 				state.Node.Id.String(),
 				string(TRx),
-				ToBase32(file.Hash[:]),
 			)
+			filePath := filepath.Join(dirToSync, ToBase32(file.Hash[:]))
 			state.Ctx.LogD("sp-file", sdsp, "opening part")
 			fd, err := os.OpenFile(
 				filePath+PartSuffix,
@@ -901,7 +906,14 @@ 					state.Ctx.LogE("sp-file", sdsp, "checksum mismatch")
 					return
 				}
 				state.Ctx.LogI("sp-done", SdsAdd(sdsp, SDS{"xx": string(TRx)}), "")
-				os.Rename(filePath+PartSuffix, filePath)
+				if err = os.Rename(filePath+PartSuffix, filePath); err != nil {
+					state.Ctx.LogE("sp-file", SdsAdd(sdsp, SDS{"err": err}), "rename")
+					return
+				}
+				if err = DirSync(dirToSync); err != nil {
+					state.Ctx.LogE("sp-file", SdsAdd(sdsp, SDS{"err": err}), "sync")
+					return
+				}
 				state.Lock()
 				delete(state.infosTheir, *file.Hash)
 				state.Unlock()
diff --git a/src/tmp.go b/src/tmp.go
index 0b1672a56890508dbdc28b9c69a68e0ef026fde497b5538fc2745fffd76a5413..a2a19cbcf91e9896525cac703e8f6a60279912a21ca95a2847068893adc2fb25 100644
--- a/src/tmp.go
+++ b/src/tmp.go
@@ -79,6 +79,19 @@ 	tmp.Fd.Close()
 	os.Remove(tmp.Fd.Name())
 }
 
+func DirSync(dirPath string) error {
+	fd, err := os.Open(dirPath)
+	if err != nil {
+		return err
+	}
+	err = fd.Sync()
+	if err != nil {
+		fd.Close()
+		return err
+	}
+	return fd.Close()
+}
+
 func (tmp *TmpFileWHash) Commit(dir string) error {
 	var err error
 	if err = os.MkdirAll(dir, os.FileMode(0777)); err != nil {
@@ -95,5 +108,8 @@ 	}
 	tmp.Fd.Close()
 	checksum := ToBase32(tmp.Hsh.Sum(nil))
 	tmp.ctx.LogD("tmp", SDS{"src": tmp.Fd.Name(), "dst": checksum}, "commit")
-	return os.Rename(tmp.Fd.Name(), filepath.Join(dir, checksum))
+	if err = os.Rename(tmp.Fd.Name(), filepath.Join(dir, checksum)); err != nil {
+		return err
+	}
+	return DirSync(dir)
 }
diff --git a/src/toss.go b/src/toss.go
index e91dd5b5403978f9a2a55c03b0967b82ca8a7a16c831ba1fb53576d8a391614c..bf8e4edd44bf0f9d3062b181d428f6d4f936019692a5cd7efc433262bafdf397 100644
--- a/src/toss.go
+++ b/src/toss.go
@@ -261,6 +261,10 @@ 				if err = os.Rename(tmp.Name(), dstPath); err != nil {
 					ctx.LogE("rx", SdsAdd(sds, SDS{"err": err}), "rename")
 					isBad = true
 				}
+				if err = DirSync(*incoming); err != nil {
+					ctx.LogE("rx", SdsAdd(sds, SDS{"err": err}), "sync")
+					isBad = true
+				}
 				delete(sds, "tmp")
 			}
 			ctx.LogI("rx", sds, "")