Das folgende Skript erzeugt ein selbstsigniertes Zertifikat mit einem RSA Key. Es können mehrere Hostnamen angegeben werden, der erste Hostname erscheint im /CN, alle anderen Hostnamen erscheinen als X509v3 Subject Alternative Names, so dass das Zertifikat für alle Hostnamen gültig ist. Ist EC_ALGO nicht gesetzt, dann wird ein RSA Zertifikat erstellt, ansonsten wird ein Key auf Basis elliptischer Kurven erstellt.

#!/bin/bash

# comment EC_ALGO if you want RSA
#EC_ALGO="prime256v1"
#EC_ALGO="secp521r1"

# Cert is DAYS valid
DAYS=3650

# Other attributes you may need
SUBJ_PREFIX="/C=DE/ST=Hessen/L=Taunusstein/O=Christian Felsing"


##############################################
# No more user changeable vars
# from here
##############################################

HOSTNAME=$1

usage() {
echo "usage: $0 <hostname> [<more hostnames>...]"
exit 1
}

if [ -z "$HOSTNAME" ]; then
usage
fi

OPENSSLCNF="/tmp/openssl.$.cf"

declare -a ARGV
ARGV=("$@")

cat > "$OPENSSLCNF" <<EOF
#
# OpenSSL example configuration file.
# This is mostly being used for generation of certificate requests.
#

# This definition stops the following lines choking if HOME isn't
# defined.
HOME = .
RANDFILE = \$ENV::HOME/.rnd

# Extra OBJECT IDENTIFIER info:
#oid_file = \$ENV::HOME/.oid
oid_section = new_oids

# To use this configuration file with the "-extfile" option of the
# "openssl x509" utility, name here the section containing the
# X.509v3 extensions to use:
# extensions =
# (Alternatively, use a configuration file that has only
# X.509v3 extensions in its main [= default] section.)

[ new_oids ]

# We can add new OIDs in here for use by 'ca', 'req' and 'ts'.
# Add a simple OID like this:
# testoid1=1.2.3.4
# Or use config file substitution like this:
# testoid2=\${testoid1}.5.6

# Policies used by the TSA examples.
tsa_policy1 = 1.2.3.4.1
tsa_policy2 = 1.2.3.4.5.6
tsa_policy3 = 1.2.3.4.5.7

####################################################################
[ ca ]
default_ca = CA_default # The default ca section

####################################################################
[ CA_default ]

dir = /etc/pki/CA # Where everything is kept
certs = \$dir/certs # Where the issued certs are kept
crl_dir = \$dir/crl # Where the issued crl are kept
database = \$dir/index.txt # database index file.
#unique_subject = no # Set to 'no' to allow creation of
# several ctificates with same subject.
new_certs_dir = \$dir/newcerts # default place for new certs.

certificate = \$dir/cacert.pem # The CA certificate
serial = \$dir/serial # The current serial number
crlnumber = \$dir/crlnumber # the current crl number
# must be commented out to leave a V1 CRL
crl = \$dir/crl.pem # The current CRL
private_key = \$dir/private/cakey.pem# The private key
RANDFILE = \$dir/private/.rand # private random number file

x509_extensions = usr_cert # The extentions to add to the cert

# Comment out the following two lines for the "traditional"
# (and highly broken) format.
name_opt = ca_default # Subject Name options
cert_opt = ca_default # Certificate field options

# Extension copying option: use with caution.
# copy_extensions = copy

# Extensions to add to a CRL. Note: Netscape communicator chokes on V2 CRLs
# so this is commented out by default to leave a V1 CRL.
# crlnumber must also be commented out to leave a V1 CRL.
# crl_extensions = crl_ext

default_days = 365 # how long to certify for
default_crl_days= 30 # how long before next CRL
default_md = sha256 # use SHA-256 by default
preserve = no # keep passed DN ordering

# A few difference way of specifying how similar the request should look
# For type CA, the listed attributes must be the same, and the optional
# and supplied fields are just that :-)
policy = policy_match

# For the CA policy
[ policy_match ]
countryName = match
stateOrProvinceName = match
organizationName = match
organizationalUnitName = optional
commonName = supplied
emailAddress = optional

# For the 'anything' policy
# At this point in time, you must list all acceptable 'object'
# types.
[ policy_anything ]
countryName = optional
stateOrProvinceName = optional
localityName = optional
organizationName = optional
organizationalUnitName = optional
commonName = supplied
emailAddress = optional

####################################################################
[ req ]
default_bits = 2048
default_md = sha256
default_keyfile = privkey.pem
distinguished_name = req_distinguished_name
attributes = req_attributes
x509_extensions = v3_ca # The extentions to add to the self signed cert

# Passwords for private keys if not present they will be prompted for
# input_password = secret
# output_password = secret

# This sets a mask for permitted string types. There are several options.
# default: PrintableString, T61String, BMPString.
# pkix : PrintableString, BMPString (PKIX recommendation before 2004)
# utf8only: only UTF8Strings (PKIX recommendation after 2004).
# nombstr : PrintableString, T61String (no BMPStrings or UTF8Strings).
# MASK:XXXX a literal mask value.
# WARNING: ancient versions of Netscape crash on BMPStrings or UTF8Strings.
string_mask = utf8only

req_extensions = v3_req # The extensions to add to a certificate request

[ req_distinguished_name ]
countryName = Country Name (2 letter code)
countryName_default = XX
countryName_min = 2
countryName_max = 2

stateOrProvinceName = State or Province Name (full name)
#stateOrProvinceName_default = Default Province

localityName = Locality Name (eg, city)
localityName_default = Default City

0.organizationName = Organization Name (eg, company)
0.organizationName_default = Default Company Ltd

# we can do this but it is not needed normally :-)
#1.organizationName = Second Organization Name (eg, company)
#1.organizationName_default = World Wide Web Pty Ltd

organizationalUnitName = Organizational Unit Name (eg, section)
#organizationalUnitName_default =

commonName = Common Name (eg, your name or your server\'s hostname)
commonName_max = 64

emailAddress = Email Address
emailAddress_max = 64

# SET-ex3 = SET extension number 3

[ req_attributes ]
challengePassword = A challenge password
challengePassword_min = 4
challengePassword_max = 20

unstructuredName = An optional company name

[ usr_cert ]

# These extensions are added when 'ca' signs a request.

# This goes against PKIX guidelines but some CAs do it and some software
# requires this to avoid interpreting an end user certificate as a CA.

basicConstraints=CA:FALSE

# Here are some examples of the usage of nsCertType. If it is omitted
# the certificate can be used for anything *except* object signing.

# This is OK for an SSL server.
# nsCertType = server

# For an object signing certificate this would be used.
# nsCertType = objsign

# For normal client use this is typical
# nsCertType = client, email

# and for everything including object signing:
# nsCertType = client, email, objsign

# This is typical in keyUsage for a client certificate.
# keyUsage = nonRepudiation, digitalSignature, keyEncipherment

# This will be displayed in Netscape's comment listbox.
nsComment = "OpenSSL Generated Certificate"

# PKIX recommendations harmless if included in all certificates.
subjectKeyIdentifier=hash
authorityKeyIdentifier=keyid,issuer

# This stuff is for subjectAltName and issuerAltname.
# Import the email address.
# subjectAltName=email:copy
# An alternative to produce certificates that aren't
# deprecated according to PKIX.
# subjectAltName=email:move

# Copy subject details
# issuerAltName=issuer:copy

#nsCaRevocationUrl = http://www.domain.dom/ca-crl.pem
#nsBaseUrl
#nsRevocationUrl
#nsRenewalUrl
#nsCaPolicyUrl
#nsSslServerName

# This is required for TSA certificates.
# extendedKeyUsage = critical,timeStamping

[ v3_req ]

# Extensions to add to a certificate request
subjectAltName = @alt_names

basicConstraints = CA:FALSE
keyUsage = nonRepudiation, digitalSignature, keyEncipherment

[alt_names]
DNS.1 = $HOSTNAME
EOF

ARGC=$#
for (( i=0; i<$ARGC; i++ )); do
ALTNAME=${ARGV[${i}]}
echo "DNS.${i} = ${ALTNAME}" >> "$OPENSSLCNF"
done

cat >> "$OPENSSLCNF" <<EOF

[ v3_ca ]

subjectAltName = @alt_names

# Extensions for a typical CA


# PKIX recommendation.

subjectKeyIdentifier=hash

authorityKeyIdentifier=keyid:always,issuer

# This is what PKIX recommends but some broken software chokes on critical
# extensions.
#basicConstraints = critical,CA:true
# So we do this instead.
basicConstraints = CA:true

# Key usage: this is typical for a CA certificate. However since it will
# prevent it being used as an test self-signed certificate it is best
# left out by default.
# keyUsage = cRLSign, keyCertSign

# Some might want this also
# nsCertType = sslCA, emailCA

# Include email address in subject alt name: another PKIX recommendation
# subjectAltName=email:copy
# Copy issuer details
# issuerAltName=issuer:copy

# DER hex encoding of an extension: beware experts only!
# obj=DER:02:03
# Where 'obj' is a standard or added object
# You can even override a supported extension:
# basicConstraints= critical, DER:30:03:01:01:FF

[ crl_ext ]

# CRL extensions.
# Only issuerAltName and authorityKeyIdentifier make any sense in a CRL.

# issuerAltName=issuer:copy
authorityKeyIdentifier=keyid:always

[ proxy_cert_ext ]
# These extensions should be added when creating a proxy certificate

# This goes against PKIX guidelines but some CAs do it and some software
# requires this to avoid interpreting an end user certificate as a CA.

basicConstraints=CA:FALSE

# Here are some examples of the usage of nsCertType. If it is omitted
# the certificate can be used for anything *except* object signing.

# This is OK for an SSL server.
# nsCertType = server

# For an object signing certificate this would be used.
# nsCertType = objsign

# For normal client use this is typical
# nsCertType = client, email

# and for everything including object signing:
# nsCertType = client, email, objsign

# This is typical in keyUsage for a client certificate.
# keyUsage = nonRepudiation, digitalSignature, keyEncipherment

# This will be displayed in Netscape's comment listbox.
nsComment = "OpenSSL Generated Certificate"

# PKIX recommendations harmless if included in all certificates.
subjectKeyIdentifier=hash
authorityKeyIdentifier=keyid,issuer

# This stuff is for subjectAltName and issuerAltname.
# Import the email address.
# subjectAltName=email:copy
# An alternative to produce certificates that aren't
# deprecated according to PKIX.
# subjectAltName=email:move

# Copy subject details
# issuerAltName=issuer:copy

#nsCaRevocationUrl = http://www.domain.dom/ca-crl.pem
#nsBaseUrl
#nsRevocationUrl
#nsRenewalUrl
#nsCaPolicyUrl
#nsSslServerName

# This really needs to be in place for it to be a proxy certificate.
proxyCertInfo=critical,language:id-ppl-anyLanguage,pathlen:3,policy:foo

####################################################################
[ tsa ]

default_tsa = tsa_config1 # the default TSA section

[ tsa_config1 ]

# These are used by the TSA reply generation only.
dir = ./demoCA # TSA root directory
serial = \$dir/tsaserial # The current serial number (mandatory)
crypto_device = builtin # OpenSSL engine to use for signing
signer_cert = \$dir/tsacert.pem # The TSA signing certificate
# (optional)
certs = \$dir/cacert.pem # Certificate chain to include in reply
# (optional)
signer_key = \$dir/private/tsakey.pem # The TSA private key (optional)

default_policy = tsa_policy1 # Policy if request did not specify it
# (optional)
other_policies = tsa_policy2, tsa_policy3 # acceptable policies (optional)
digests = sha1, sha256, sha384, sha512 # Acceptable message digests (mandatory)
accuracy = secs:1, millisecs:500, microsecs:100 # (optional)
clock_precision_digits = 0 # number of digits after dot. (optional)
ordering = yes # Is ordering defined for timestamps?
# (optional, default: no)
tsa_name = yes # Must the TSA name be included in the reply?
# (optional, default: no)
ess_cert_id_chain = no # Must the ESS cert id chain be included?
# (optional, default: no)
EOF

umask 077
OUTFILE=${HOSTNAME}.crt

if [ -z "$EC_ALGO" ]; then
openssl req -x509 -config "$OPENSSLCNF" -nodes -newkey rsa:4096 -sha256 -subj "${SUBJ_PREFIX}/CN=${HOSTNAME}" -keyout ${HOSTNAME}.key -out ${OUTFILE} -days $DAYS
else
openssl ecparam -out "${HOSTNAME}.key" -name ${EC_ALGO} -genkey
openssl req -x509 -new -config "$OPENSSLCNF" -nodes -key "${HOSTNAME}.key" -sha256 -subj "${SUBJ_PREFIX}/CN=${HOSTNAME}" -out ${OUTFILE} -days $DAYS
fi

chmod 644 "${OUTFILE}"
umask 022

rm -f "$OPENSSLCNF"
Das Skript erzeugt eine temporäre openssl.cnf Datei.