Initial import.

cmd/certchain/README

@@ -0,0 +1,19 @@
+certchain
+
+This is a utility for printing the X.509 certificate chain from a TLS
+connection.
+
+Note: while this will accept more than one server, it will print all
+of the chains without any indication where one chain ends and the next
+begins. This was the intended behaviour for the use case, but it may
+not be applicable in other cases.
+
+There are no knobs.
+
+Examples:
+	$ certchain www.kyleisom.net
+	-----BEGIN CERTIFICATE-----
+	MIIFUTCCBDmgAwIBAgIQaaTVw0yZFGAYvFDKAIo4BzANBgkqhkiG9w0BAQsFADCB
+	kDELMAkGA1UEBhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4G
+	A1UEBxMHU2FsZm9yZDEaMBgGA1UEChMRQ09NT0RPIENBIExpbWl0ZWQxNjA0BgNV
+	...

cmd/certchain/certchain.go

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+package main
+
+import (
+	"crypto/tls"
+	"encoding/pem"
+	"flag"
+	"fmt"
+	"regexp"
+
+	"github.com/kisom/goutils/die"
+)
+
+var hasPort = regexp.MustCompile(`:\d+$`)
+
+func main() {
+	flag.Parse()
+
+	for _, server := range flag.Args() {
+		if !hasPort.MatchString(server) {
+			server += ":443"
+		}
+
+		var chain string
+
+		conn, err := tls.Dial("tcp", server, nil)
+		die.If(err)
+
+		details := conn.ConnectionState()
+		for _, cert := range details.PeerCertificates {
+			p := pem.Block{
+				Type:  "CERTIFICATE",
+				Bytes: cert.Raw,
+			}
+			chain += string(pem.EncodeToMemory(&p))
+		}
+
+		fmt.Println(chain)
+	}
+}