TLS: Add different client cert support. (#8076)

This adds a new `tls-client-cert-file` and `tls-client-key-file`
configuration directives which make it possible to use different
certificates for the TLS-server and TLS-client functions of Redis.

This is an optional directive. If it is not specified the `tls-cert-file`
and `tls-key-file` directives are used for TLS client functions as well.

Also, `utils/gen-test-certs.sh` now creates additional server-only and client-only certs and will skip intensive operations if target files already exist.

utils/gen-test-certs.sh

@@ -1,23 +1,58 @@
 #!/bin/bash
+
+# Generate some test certificates which are used by the regression test suite:
+#
+#   tests/tls/ca.{crt,key}          Self signed CA certificate.
+#   tests/tls/redis.{crt,key}       A certificate with no key usage/policy restrictions.
+#   tests/tls/client.{crt,key}      A certificate restricted for SSL client usage.
+#   tests/tls/server.{crt,key}      A certificate restricted fro SSL server usage.
+#   tests/tls/redis.dh              DH Params file.
+
+generate_cert() {
+    local name=$1
+    local cn="$2"
+    local opts="$3"
+
+    local keyfile=tests/tls/${name}.key
+    local certfile=tests/tls/${name}.crt
+
+    [ -f $keyfile ] || openssl genrsa -out $keyfile 2048
+    openssl req \
+        -new -sha256 \
+        -subj "/O=Redis Test/CN=$cn" \
+        -key $keyfile | \
+        openssl x509 \
+            -req -sha256 \
+            -CA tests/tls/ca.crt \
+            -CAkey tests/tls/ca.key \
+            -CAserial tests/tls/ca.txt \
+            -CAcreateserial \
+            -days 365 \
+            $opts \
+            -out $certfile
+}
+
 mkdir -p tests/tls
-openssl genrsa -out tests/tls/ca.key 4096
+[ -f tests/tls/ca.key ] || openssl genrsa -out tests/tls/ca.key 4096
 openssl req \
     -x509 -new -nodes -sha256 \
     -key tests/tls/ca.key \
     -days 3650 \
     -subj '/O=Redis Test/CN=Certificate Authority' \
     -out tests/tls/ca.crt
-openssl genrsa -out tests/tls/redis.key 2048
-openssl req \
-    -new -sha256 \
-    -key tests/tls/redis.key \
-    -subj '/O=Redis Test/CN=Server' | \
-    openssl x509 \
-        -req -sha256 \
-        -CA tests/tls/ca.crt \
-        -CAkey tests/tls/ca.key \
-        -CAserial tests/tls/ca.txt \
-        -CAcreateserial \
-        -days 365 \
-        -out tests/tls/redis.crt
-openssl dhparam -out tests/tls/redis.dh 2048
+
+cat > tests/tls/openssl.cnf <<_END_
+[ server_cert ]
+keyUsage = digitalSignature, keyEncipherment
+nsCertType = server
+
+[ client_cert ]
+keyUsage = digitalSignature, keyEncipherment
+nsCertType = client
+_END_
+
+generate_cert server "Server-only" "-extfile tests/tls/openssl.cnf -extensions server_cert"
+generate_cert client "Client-only" "-extfile tests/tls/openssl.cnf -extensions client_cert"
+generate_cert redis "Generic-cert"
+
+[ -f tests/tls/redis.dh ] || openssl dhparam -out tests/tls/redis.dh 2048