ovs-pki: generate x.509 v3 certificate

This patch modifies ovs-pki to generate x.509 version 3 certificate.
Compared with the x.509 v1 certificate generated by ovs-pki, version 3
certificate adds subjectAltName field and sets its value the same as
common name (CN). The main reason for this change is to enable
strongSwan IKE daemon to extract certificate identity string from the
subjectAltName field, which makes OVN IPsec implementation easier.

Signed-off-by: Qiuyu Xiao <qiuyu.xiao.qyx@gmail.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>

NEWS

@@ -59,6 +59,9 @@ v2.10.0 - xx xxx xxxx
        both kernel datapath and userspace datapath.
      * Added port-based and flow-based ERSPAN tunnel port support, added
        OpenFlow rules matching ERSPAN fields. See ovs-fields(7).
+   - ovs-pki
+     * ovs-pki now generates x.509 version 3 certificate. The new format adds
+       subjectAltName field and sets its value the same as common name (CN).
 
 v2.9.0 - 19 Feb 2018
 --------------------

utilities/ovs-pki.in

@@ -284,7 +284,7 @@ policy         = policy                # default policy
 email_in_dn    = no                    # Don't add the email into cert DN
 name_opt       = ca_default            # Subject name display option
 cert_opt       = ca_default            # Certificate display option
-copy_extensions = none                 # Don't copy extensions from request
+copy_extensions = copy                 # Copy extensions from request
 unique_subject = no                    # Allow certs with duplicate subjects
 
 # For the CA policy
@@ -295,6 +295,13 @@ organizationName        = match
 organizationalUnitName  = optional
 commonName              = supplied
 emailAddress            = optional
+
+# For the x509v3 extension
+[ ca_cert ]
+basicConstraints=CA:true
+
+[ usr_cert ]
+basicConstraints=CA:false
 EOF
         fi
 
@@ -307,7 +314,8 @@ EOF
         openssl req -config ca.cnf -nodes \
             -newkey $newkey -keyout private/cakey.pem -out careq.pem \
             1>&3 2>&3
-        openssl ca -config ca.cnf -create_serial -out cacert.pem \
+        openssl ca -config ca.cnf -create_serial \
+            -extensions ca_cert -out cacert.pem \
             -days 3650 -batch -keyfile private/cakey.pem -selfsign \
             -infiles careq.pem 1>&3 2>&3
         chmod 0700 private/cakey.pem
@@ -445,6 +453,7 @@ make_request() {
 [ req ]
 prompt = no
 distinguished_name = req_distinguished_name
+req_extensions = v3_req
 
 [ req_distinguished_name ]
 C = US
@@ -453,6 +462,9 @@ L = Palo Alto
 O = Open vSwitch
 OU = Open vSwitch certifier
 CN = $cn
+
+[ v3_req ]
+subjectAltName = DNS:$cn
 EOF
     if test $keytype = rsa; then
         (umask 077 && openssl genrsa -out "$1-privkey.pem" $bits) 1>&3 2>&3 \
@@ -481,7 +493,7 @@ sign_request() {
     esac
 
     (cd "$pkidir/${type}ca" && 
-     openssl ca -config ca.cnf -batch -in "$request_file") \
+     openssl ca -config ca.cnf -extensions usr_cert -batch -in "$request_file") \
         > "$2.tmp$$" 2>&3
     mv "$2.tmp$$" "$2"
 }
@@ -529,11 +541,16 @@ elif test "$command" = self-sign; then
     must_exist "$arg1-req.pem"
     must_exist "$arg1-privkey.pem"
     must_not_exist "$arg1-cert.pem"
+    make_tmpdir
+    cat > "$TMP/v3.ext" <<EOF
+subjectAltName = DNS:$arg1
+EOF
 
     # Create both the private key and certificate with restricted permissions.
     (umask 077 && \
      openssl x509 -in "$arg1-req.pem" -out "$arg1-cert.pem.tmp" \
-        -signkey "$arg1-privkey.pem" -req -days 3650 -text) 2>&3 || exit $?
+                  -signkey "$arg1-privkey.pem" -req -days 3650 -text \
+                  -extfile $TMP/v3.ext) 2>&3 || exit $?
 
     # Reset the permissions on the certificate to the user's default.
     cat "$arg1-cert.pem.tmp" > "$arg1-cert.pem"