From e9682162ac908e9b9d81f3378faf8b38d1baa630 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Sun, 28 Apr 2019 12:27:06 +0200
Subject: updater: add initial skeleton

---
 updater/signify.go | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 updater/signify.go

(limited to 'updater/signify.go')

diff --git a/updater/signify.go b/updater/signify.go
new file mode 100644
index 00000000..d4605cbb
--- /dev/null
+++ b/updater/signify.go
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package updater
+
+import (
+	"bytes"
+	"encoding/base64"
+	"encoding/hex"
+	"errors"
+	"golang.org/x/crypto/blake2b"
+	"golang.org/x/crypto/ed25519"
+	"strings"
+)
+
+/*
+ * Generate with:
+ *   $ b2sum -l 256 *.msi > list
+ *   $ signify -S -e -s release.sec -m list
+ *   $ upload ./list.sec
+ */
+
+type fileList map[string][blake2b.Size256]byte
+
+func readFileList(input []byte) (fileList, error) {
+	publicKeyBytes, err := base64.StdEncoding.DecodeString(releasePublicKeyBase64)
+	if err != nil || len(publicKeyBytes) != ed25519.PublicKeySize+10 || publicKeyBytes[0] != 'E' || publicKeyBytes[1] != 'd' {
+		return nil, errors.New("Invalid public key")
+	}
+	publicKeyBytes = publicKeyBytes[10:]
+	lines := bytes.SplitN(input, []byte{'\n'}, 3)
+	if len(lines) != 3 {
+		return nil, errors.New("Signature input has too few lines")
+	}
+	if !bytes.HasPrefix(lines[0], []byte("untrusted comment: ")) {
+		return nil, errors.New("Signature input is missing untrusted comment")
+	}
+	signatureBytes, err := base64.StdEncoding.DecodeString(string(lines[1]))
+	if err != nil {
+		return nil, errors.New("Signature input is not valid base64")
+	}
+	if len(signatureBytes) != ed25519.SignatureSize+10 || signatureBytes[0] != 'E' || signatureBytes[1] != 'd' {
+		return nil, errors.New("Signature input bytes are incorrect length or represent invalid signature type")
+	}
+	signatureBytes = signatureBytes[10:]
+	if !ed25519.Verify(publicKeyBytes, lines[2], signatureBytes) {
+		return nil, errors.New("Signature is invalid")
+	}
+	fileLines := strings.Split(string(lines[2]), "\n")
+	fileHashes := make(map[string][blake2b.Size256]byte, len(fileLines))
+	for index, line := range fileLines {
+		if len(line) == 0 && index == len(fileLines)-1 {
+			break
+		}
+		components := strings.SplitN(line, "  ", 2)
+		if len(components) != 2 {
+			return nil, errors.New("File hash line has too few components")
+		}
+		maybeHash, err := hex.DecodeString(components[0])
+		if err != nil || len(maybeHash) != blake2b.Size256 {
+			return nil, errors.New("File hash is invalid base64 or incorrect number of bytes")
+		}
+		var hash [blake2b.Size256]byte
+		copy(hash[:], maybeHash)
+		fileHashes[components[1]] = hash
+	}
+	if len(fileHashes) == 0 {
+		return nil, errors.New("No file hashes found in signed input")
+	}
+	return fileHashes, nil
+}
-- 
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