Generate temporary config file when generating certificates

The putenv trick doesn't work on ZTS Windows, so generate a new
openssl config every time.

Author: nikic

ext/openssl/tests/CertificateGenerator.inc

@@ -3,7 +3,6 @@
 class CertificateGenerator
 {
     const CONFIG = __DIR__. DIRECTORY_SEPARATOR . 'openssl.cnf';
-    const SAN_CONFIG = __DIR__ . DIRECTORY_SEPARATOR . 'san.cnf';
 
     /** @var resource */
     private $ca;
@@ -96,32 +95,56 @@ class CertificateGenerator
             $dn['commonName'] = $commonNameForCert;
         }
 
-        $config = [
-            'digest_alg' => 'sha256',
-            'req_extensions' => 'v3_req',
-            'x509_extensions' => 'usr_cert',
-        ];
-        if ($subjectAltName !== null) {
-            putenv("PHP_SUBJECTALTNAME=$subjectAltName");
-            $config['config'] = self::SAN_CONFIG;
-        }
-
-        $this->lastKey = self::generateKey($keyLength);
-        $this->lastCert = openssl_csr_sign(
-            openssl_csr_new($dn, $this->lastKey, $config),
-            $this->ca,
-            $this->caKey,
-            /* days */ 2,
-            $config,
-        );
+        $subjectAltNameConfig =
+            $subjectAltName ? "subjectAltName = $subjectAltName" : "";
+        $configCode = <<<CONFIG
+[ req ]
+distinguished_name = req_distinguished_name
+default_md = sha256
+
+[ req_distinguished_name ]
+
+[ v3_req ]
+basicConstraints = CA:FALSE
+keyUsage = nonRepudiation, digitalSignature, keyEncipherment
+$subjectAltNameConfig
+
+[ usr_cert ]
+basicConstraints = CA:FALSE
+$subjectAltNameConfig
+CONFIG;
+        $configFile = $file . '.cnf';
+        file_put_contents($configFile, $configCode);
+
+        try {
+            $config = [
+                'config' => $configFile,
+                'req_extensions' => 'v3_req',
+                'x509_extensions' => 'usr_cert',
+            ];
+
+            $this->lastKey = self::generateKey($keyLength);
+            $this->lastCert = openssl_csr_sign(
+                openssl_csr_new($dn, $this->lastKey, $config),
+                $this->ca,
+                $this->caKey,
+                /* days */ 2,
+                $config,
+            );
+            if (!$this->lastCert) {
+                throw new Exception('Failed to create certificate');
+            }
 
-        $certText = '';
-        openssl_x509_export($this->lastCert, $certText);
+            $certText = '';
+            openssl_x509_export($this->lastCert, $certText);
 
-        $keyText = '';
-        openssl_pkey_export($this->lastKey, $keyText);
+            $keyText = '';
+            openssl_pkey_export($this->lastKey, $keyText);
 
-        file_put_contents($file, $certText . PHP_EOL . $keyText);
+            file_put_contents($file, $certText . PHP_EOL . $keyText);
+        } finally {
+            unlink($configFile);
+        }
     }
 
     public function getCertDigest($algo)