infrastructure:securite:ssl:ca-creation [Grohub wiki]

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====== Création d'une CA ======
{{tag>sécurité ssl CA}}
Afin de pouvoir administrer nos certificats, nous créons une CA. Dans l'immédiat, tout se fera en ligne de commande.

===== Configuration du CA =====
Nous créons le répertoire qui va accueillir le CA, et les répertoires qui le compose, et sécurisons le répertoire "private"
<code>
# sudo mkdir -p /etc/ssl/CA/{certs,crl,newcerts,private}
# chmod 700 /etc/ssl/CA/private
# cd /etc/ssl/CA
</code>

Nous créons le fichier d'index
<code>
# touch index.txt
# echo 1000 > serial
</code>

Nous copions le fichier openssl.cnf depuis /etc/ssl/ dans /etc/ssl/CA
<code>
# cp -v /etc/ssl/openssl.cnf /etc/ssl/CA/openssl.cnf
</code>

Nous adaptons le fichier openssl.cnf pour qu'il ressemble à cela
<code>
#
# 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/ssl/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 certs with same subject.
new_certs_dir	= $dir/newcerts		# default place for new certs.

certificate	= $dir/certs/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/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 extensions 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	= 375			# how long to certify for
default_crl_days= 30			# how long before next CRL
default_md	= default		# use public key default MD
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_keyfile		= privkey.pem
distinguished_name	= req_distinguished_name
attributes		= req_attributes
x509_extensions	= v3_ca	# The extensions 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		= FR
countryName_min			= 2
countryName_max			= 2

stateOrProvinceName		= State or Province Name (full name)
stateOrProvinceName_default	= Var

localityName			= Locality Name (eg, city)
localityName_default		= Vinon

0.organizationName		= Organization Name (eg, company)
0.organizationName_default	= Grohub Certificate Authority

# 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	= Security Team

commonName			= Common Name (e.g. server FQDN or YOUR name)
commonName_max			= 64

emailAddress			= Email Address
emailAddress_max		= 64
emailAddress_default		= sec@grohub.org

# 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
extendedKeyUsage = clientAuth, emailProtection

[ v3_req ]

# Extensions to add to a certificate request

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

[ v3_ca ]


# Extensions for a typical CA


# PKIX recommendation.

subjectKeyIdentifier=hash

authorityKeyIdentifier=keyid:always,issuer

basicConstraints = critical,CA:true, pathlen:0

# 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
keyUsage = critical, digitalSignature, 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)
signer_digest  = sha256			# Signing digest to use. (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)

[ v3_intermediate_ca ]
# Extensions for a typical intermediate CA (`man x509v3_config`).
subjectKeyIdentifier = hash
authorityKeyIdentifier = keyid:always,issuer
basicConstraints = critical, CA:true, pathlen:0
keyUsage = critical, digitalSignature, cRLSign, keyCertSign

[ server_cert ]
# Extensions for server certificates (`man x509v3_config`).
basicConstraints = CA:FALSE
nsCertType = server
nsComment = "OpenSSL Generated Server Certificate"
subjectKeyIdentifier = hash
authorityKeyIdentifier = keyid,issuer:always
keyUsage = critical, digitalSignature, keyEncipherment
extendedKeyUsage = serverAuth

[ ocsp ]
# Extension for OCSP signing certificates (`man ocsp`).
basicConstraints = CA:FALSE
subjectKeyIdentifier = hash
authorityKeyIdentifier = keyid,issuer
keyUsage = critical, digitalSignature
extendedKeyUsage = critical, OCSPSigning
</code>

==== Création de la clé root ====
Nous créons la clé root du CA
<code>
# openssl genrsa -aes256 -out private/cakey.pem 4096
</code>

Entrez deux fois la passphrase que vous avez défini
<code>
Enter pass phrase for private/cakey.pem:
Verifying - Enter pass phrase for private/cakey.pem:
</code>

Et nous sécurisons la clé
<code>
# chmod 400 private/cakey.pem
</code>

==== Création du certificat root ====
Nous créons le certificat
<code>
# openssl req -config openssl.cnf -key private/cakey.pem -new -x509 -days 7300 -sha256 -extensions v3_ca -out certs/cacert.pem
</code>

Vous devez saisir la passphrase de la clé précédemment définie
<code>
Enter pass phrase for private/cakey.pem:
</code>

Répondez ensuite aux questions, ou laissez le choix par défaut (information entre crochets)
<code>
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [FR]:
State or Province Name (full name) [Var]:
Locality Name (eg, city) [Vinon]:
Organization Name (eg, company) [Grohub Certificate Authority]:
Organizational Unit Name (eg, section) [Security Team]:
Common Name (e.g. server FQDN or YOUR name) []:Grohub Root CA
Email Address [sec@grohub.org]:
</code>

Nous vérifions le certificat
<code>
# openssl x509 -noout -text -in certs/cacert.pem
</code>

===== Configuration du certificat intermédiaire =====
Nous créons le répertoire qui va accueillir le certificat intermédiaire
<code>
# mkdir /etc/ssl/CA/intermediate
</code>

Nous nous plaçons dans le répertoire, et créons l'arborescence
<code>

# mkdir -p /etc/ssl/CA/intermediate/{certs,crl,csr,newcerts,private}
# chmod 700 /etc/ssl/CA/intermediate/private
# cd /etc/ssl/CA/intermediate
# touch index.txt
# echo 1000 > serial
</code>

Nous ajoutons un fichier pour garder une trace de la liste des révocation de certificats
<code>
# echo 1000 > /etc/ssl/CA/intermediate/crlnumber
</code>

Nous copions le fichier de configuration
<code>
# cp -v /etc/ssl/CA/openssl.cnf /etc/ssl/CA/intermediate/openssl.cnf
</code>

Nous changeons les éléments suivants
<code>
[ CA_default ]
dir             = /root/ca/intermediate
private_key     = $dir/private/intermediatekey.pem
certificate     = $dir/certs/intermediatecert.pem
crl             = $dir/crl/intermediatecrl.pem
policy          = policy_loose
</code>

==== Création du certificat intermédiaire ====
<code>
cd /etc/ssl/CA
# openssl genrsa -aes256 -out intermediate/private/intermediatekey.pem 4096
</code>

Nous saisissons une passphrase
<code>
Enter pass phrase for intermediate/private/intermediatekey.pem:
Verifying - Enter pass phrase for intermediate/private/intermediatekey.pem:
</code>

Nous sécurisons la clé
<code>
chmod 400 intermediate/private/intermediatekey.pem
</code>

==== Création du Certificat Signing Request (CSR) ====
Nous créons le CSR
<code>
# cd /etc/ssl/CA
# openssl req -config intermediate/openssl.cnf -new -sha256 -key intermediate/private/intermediatekey.pem -out intermediate/csr/intermediatecsr.pem
</code>

==== Création du certificat ====
Nous créons le certificat
<code>
# cd /etc/ssl/CA
# openssl ca -config openssl.cnf -extensions v3_intermediate_ca -days 3650 -notext -md sha256 -in intermediate/csr/intermediatecsr.pem -out intermediate/certs/intermediatecert.pem
</code>

Nous confirmons deux fois avec "y"
<code>
Sign the certificate? [y/n]:y
1 out of 1 certificate requests certified, commit? [y/n]y
</code>

Nous sécurisons le certificat
<code>
# chmod 444 intermediate/certs/intermediatecert.pem
</code>

Pour vérifier le certificat
<code>
# openssl x509 -noout -text -in intermediate/certs/intermediatecert.pem
</code>

Pour vérifier
<code>
# openssl verify -CAfile certs/cacert.pem intermediate/certs/intermediatecert.pem
</code>

Vous devriez avoir cette réponse
<code>
intermediate/certs/intermediatecert.pem: OK
</code>

==== Création du fichier de chaîne de certificat =====
<code>
# cat intermediate/certs/intermediatecert.pem certs/cacert.pem > intermediate/certs/ca-chaincert.pem
</code>

Nous sécurisons le fichier
<code>
# chmod 444 intermediate/certs/ca-chaincert.pem
</code>

===== Liens =====
  * [[https://jamielinux.com/docs/openssl-certificate-authority/|OpenSSL Certificate Authority]]