From 30b9e5d5f5a29a3d83f9e16c9b606c903f750acc Mon Sep 17 00:00:00 2001
From: Rasmus Dahlberg <rasmus@mullvad.net>
Date: Sun, 27 Mar 2022 15:26:37 +0200
Subject: add start on sigsum-debug utility

---
 cmd/sigsum-debug/genkey.go  | 19 ++++++++++
 cmd/sigsum-debug/hashkey.go | 24 ++++++++++++
 cmd/sigsum-debug/main.go    | 92 +++++++++++++++++++++++++++++++++++++++++++++
 cmd/sigsum-debug/pubkey.go  | 27 +++++++++++++
 cmd/sigsum-debug/util.go    | 24 ++++++++++++
 5 files changed, 186 insertions(+)
 create mode 100644 cmd/sigsum-debug/genkey.go
 create mode 100644 cmd/sigsum-debug/hashkey.go
 create mode 100644 cmd/sigsum-debug/main.go
 create mode 100644 cmd/sigsum-debug/pubkey.go
 create mode 100644 cmd/sigsum-debug/util.go

diff --git a/cmd/sigsum-debug/genkey.go b/cmd/sigsum-debug/genkey.go
new file mode 100644
index 0000000..87175a5
--- /dev/null
+++ b/cmd/sigsum-debug/genkey.go
@@ -0,0 +1,19 @@
+package main
+
+import (
+	"crypto/ed25519"
+	"crypto/rand"
+	"fmt"
+
+	"git.sigsum.org/sigsum-lib-go/pkg/hex"
+)
+
+func CmdGenKey() error {
+	_, priv, err := ed25519.GenerateKey(rand.Reader)
+	if err != nil {
+		return fmt.Errorf("failed generating key-pair: %v", err)
+	}
+
+	fmt.Printf("%s\n", hex.Serialize(priv[:]))
+	return nil
+}
diff --git a/cmd/sigsum-debug/hashkey.go b/cmd/sigsum-debug/hashkey.go
new file mode 100644
index 0000000..d9b37dd
--- /dev/null
+++ b/cmd/sigsum-debug/hashkey.go
@@ -0,0 +1,24 @@
+package main
+
+import (
+	"crypto/ed25519"
+	"fmt"
+
+	"git.sigsum.org/sigsum-lib-go/pkg/hex"
+	"git.sigsum.org/sigsum-lib-go/pkg/types"
+)
+
+func CmdHashKey() error {
+	b, err := decodeHexFromStdin()
+	if err != nil {
+		return err
+	}
+	if len(b) != ed25519.PublicKeySize {
+		return fmt.Errorf("invalid private key: size")
+	}
+	pub := ed25519.PublicKey(b)
+	keyHash := types.HashFn(pub)
+
+	fmt.Printf("%s\n", hex.Serialize(keyHash[:]))
+	return nil
+}
diff --git a/cmd/sigsum-debug/main.go b/cmd/sigsum-debug/main.go
new file mode 100644
index 0000000..1d9e769
--- /dev/null
+++ b/cmd/sigsum-debug/main.go
@@ -0,0 +1,92 @@
+// package main provides a tool named sigsum-debug.
+//
+// Install as follows:
+//
+//     $ go install -ldflags="-X 'main.someVersion=git commit $(git rev-list -1 HEAD)'"
+//
+// Usage:
+//
+//     $ sigsum-debug help
+//
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"os"
+)
+
+const usage = `sigsum-debug version %s
+
+Usage:
+    sigsum-debug help
+        Outputs a usage message.
+
+    sigsum-debug genkey
+        Outputs a new private key.
+
+    sigsum-debug pubkey
+        Reads a private key from stdin and output its public key.
+
+    sigsum-debug hashkey
+        Reads a public key from stdin and output its key hash.
+`
+
+var (
+	someVersion = "unknown"
+)
+
+func main() {
+	log.SetFlags(0)
+
+	var err error
+	switch cmd := parseCommand(); cmd.Name() {
+	case "help":
+		cmd.Usage()
+	case "genkey":
+		err = CmdGenKey()
+	case "pubkey":
+		err = CmdPubKey()
+	case "hashkey":
+		err = CmdHashKey()
+	default:
+		err = fmt.Errorf("invalid command %q, try %q", cmd.Name(), "sigsum help")
+	}
+
+	if err != nil {
+		log.Printf("%s", err)
+		os.Exit(1)
+	}
+}
+
+func parseCommand() *flag.FlagSet {
+	args := os.Args
+	if len(args) < 2 {
+		args = append(args, "")
+	}
+
+	fs := flag.NewFlagSet(args[1], flag.ExitOnError)
+	fs.Usage = func() {
+		log.Printf(usage, someVersion)
+	}
+	registerOptions(fs)
+	fs.Parse(args[2:])
+	return fs
+}
+
+func registerOptions(fs *flag.FlagSet) {
+	switch cmd := fs.Name(); cmd {
+	default:
+	}
+}
+
+func registerStringOption(fs *flag.FlagSet, opt *string, short, long, value string) {
+	fs.StringVar(opt, short, value, "")
+	fs.StringVar(opt, long, value, "")
+}
+
+func registerUint64Option(fs *flag.FlagSet, opt *uint64, short, long string, value uint64) {
+	fs.Uint64Var(opt, short, value, "")
+	fs.Uint64Var(opt, long, value, "")
+}
diff --git a/cmd/sigsum-debug/pubkey.go b/cmd/sigsum-debug/pubkey.go
new file mode 100644
index 0000000..586d19a
--- /dev/null
+++ b/cmd/sigsum-debug/pubkey.go
@@ -0,0 +1,27 @@
+package main
+
+import (
+	"crypto/ed25519"
+	"fmt"
+
+	"git.sigsum.org/sigsum-lib-go/pkg/hex"
+)
+
+func CmdPubKey() error {
+	b, err := decodeHexFromStdin()
+	if err != nil {
+		return err
+	}
+	if len(b) != ed25519.PrivateKeySize {
+		return fmt.Errorf("invalid private key: size")
+	}
+
+	priv := ed25519.PrivateKey(b)
+	pub, ok := priv.Public().(ed25519.PublicKey)
+	if !ok {
+		return fmt.Errorf("failed converting to public key")
+	}
+
+	fmt.Printf("%s\n", hex.Serialize(pub[:]))
+	return nil
+}
diff --git a/cmd/sigsum-debug/util.go b/cmd/sigsum-debug/util.go
new file mode 100644
index 0000000..d7ba6a8
--- /dev/null
+++ b/cmd/sigsum-debug/util.go
@@ -0,0 +1,24 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"git.sigsum.org/sigsum-lib-go/pkg/hex"
+)
+
+func decodeHexFromStdin() ([]byte, error) {
+	b, err := ioutil.ReadAll(os.Stdin)
+	if err != nil {
+		return nil, fmt.Errorf("failed reading stdin: %v", err)
+	}
+
+	b, err = hex.Deserialize(string(bytes.TrimSpace(b)))
+	if err != nil {
+		return nil, fmt.Errorf("invalid private key: %v", err)
+	}
+
+	return b, nil
+}
-- 
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