Add a script to use openssl to generate root/server/client ssl certs.

Signed-off-by: Ying Li <ying.li@docker.com>

opensslCertGen.sh

@@ -0,0 +1,133 @@
+#!/usr/bin/env bash
+
+# Script to be used for generating testing certs only - for a production system,
+# a public CA or an internal CA should be used
+
+
+CLIENT_USAGE=<<EOL
+Generate a self-signed client cert and key to be used in mutual TLS.
+
+${0} client [-o <output file prefix>]
+
+Example:
+    ${0} client -o clienttls
+EOL
+
+SERVER_USAGE=<<EOL
+Generate a self-signed cert key and certificate.
+
+${0} server -n <common name> [-o <output file prefix>]
+    [-r <root key if don't want it self-signed>]
+    [-a <subjectAltName>] [-a <subjectAltName>] ...
+
+Example:
+    ${0} server -o servertls -n notary-server -a DNS:notaryserver \
+        -a DNS:notary_server -a IP:127.0.0.1"
+EOL
+
+if [[ -z "${1}" ]]; then
+    printf "${CLIENT_USAGE}\n\n${SERVER_USAGE}\n\n"
+    exit 1
+fi
+
+OPENSSLCNF=
+for path in /etc/openssl/openssl.cnf /etc/ssl/openssl.cnf /usr/local/etc/openssl/openssl.cnf; do
+    if [[ -e ${path} ]]; then
+        OPENSSLCNF=${path}
+    fi
+done
+if [[ -z ${OPENSSLCNF} ]]; then
+    printf "Could not find openssl.cnf"
+    exit 1
+fi
+
+if [[ "${1}" == "client" ]]; then
+    # Generate client keys - ensure that these keys are NOT CA's, otherwise
+    # any client that is compromised can sign any number of other client
+    # certs.
+    OUT="clienttls"
+    while getopts "o:" opt "${@:2}"; do
+        case "${opt}" in
+            o)
+                OUT="${OPTARG}"
+                ;;
+            *)
+                printf "${CLIENT_USAGE}"
+                exit 1
+                ;;
+        esac
+    done
+
+    openssl genrsa -out "${OUT}.key" 4096
+    openssl req -new -key "${OUT}.key" -out "${OUT}.csr" \
+        -subj '/C=US/ST=CA/L=San Francisco/O=Docker/CN=Notary Testing Client Auth'
+
+    cat > "${OUT}.cnf" <<EOL
+[ssl_client]
+basicConstraints = critical,CA:FALSE
+nsCertType = critical, client
+keyUsage = critical, digitalSignature, nonRepudiation
+extendedKeyUsage = critical, clientAuth
+authorityKeyIdentifier=keyid,issuer
+EOL
+
+    openssl x509 -req -days 3650 -in "${OUT}.csr" -signkey "${OUT}.key" \
+        -out "${OUT}.crt" -extfile "${OUT}.cnf" -extensions ssl_client
+
+    rm "${OUT}.cnf" "${OUT}.csr"
+fi
+
+if [[ "${1}" == "server" ]]; then
+    # Create a server certificate
+
+    OUT="servertls"
+    COMMONNAME=
+    SAN=
+    while getopts ":o:n:a:" opt "${@:2}"; do
+        case "${opt}" in
+            o)
+                OUT="${OPTARG}"
+                ;;
+            n)
+                COMMONNAME="${OPTARG}"
+                ;;
+            a)
+                SAN="${SAN} ${OPTARG}"
+                ;;
+            *)
+                printf "${SERVER_USAGE}\n\n"
+                exit 1
+                ;;
+        esac
+    done
+
+    if [[ -z "${COMMONNAME}" ]]; then
+        printf "Please provide a common name/domain for the cert."
+        printf "\n\n${SERVER_USAGE}\n\n"
+        exit 1
+    fi
+    PPRINT_DOMAINS="${COMMONNAME}$(printf ", %s" "${SAN[@]}")"
+    printf "Generating server certificate for domains: ${PPRINT_DOMAINS}\n\n"
+
+    # see https://www.openssl.org/docs/manmaster/apps/x509v3_config.html for
+    # more information on extensions
+    cat "${OPENSSLCNF}" > "${OUT}.cnf"
+    cat >> "${OUT}.cnf" <<EOL
+[ v3_req ]
+basicConstraints = critical,CA:FALSE
+nsCertType = critical, server
+keyUsage = critical, digitalSignature, nonRepudiation
+extendedKeyUsage = critical, serverAuth
+authorityKeyIdentifier=keyid,issuer
+EOL
+    if [[ -n "${SAN}" ]]; then
+        printf "subjectAltName=$(echo ${SAN[@]} | tr ' ' ,)" >> "${OUT}.cnf"
+    fi
+
+    openssl genrsa -out "${OUT}.key" 4096
+    openssl req -new -nodes -key "${OUT}.key" -out "${OUT}.csr" \
+        -subj "/C=US/ST=CA/L=San Francisco/O=Docker/CN=${COMMONNAME}" \
+        -config "${OUT}.cnf" -extensions "v3_req"
+    openssl x509 -req -days 3650 -in "${OUT}.csr" -signkey "${OUT}.key" \
+        -out "${OUT}.crt" -extensions v3_req -extfile "${OUT}.cnf"
+fi