[ci skip] If possible, always negotiate for TLS 1.0, TLS 1.1, TLS 1.2 for SMTP connections in CI_Email

1 files changed, 13 insertions, 1 deletions

diff --git a/system/libraries/Email.php b/system/libraries/Email.php
index 967a0019a..71740ee5e 100644
--- a/system/libraries/Email.php
+++ b/system/libraries/Email.php
@@ -2074,7 +2074,19 @@ class CI_Email {
 			$this->_send_command('hello');
 			$this->_send_command('starttls');
 
-			$crypto = stream_socket_enable_crypto($this->_smtp_connect, TRUE, STREAM_CRYPTO_METHOD_TLS_CLIENT);
+			/**
+			 * STREAM_CRYPTO_METHOD_TLS_CLIENT is quite the mess ...
+			 *
+			 * - On PHP <5.6 it doesn't even mean TLS, but SSL 2.0, and there's no option to use actual TLS
+			 * - On PHP 5.6.0-5.6.6, >=7.2 it means negotiation with any of TLS 1.0, 1.1, 1.2
+			 * - On PHP 5.6.7-7.1.* it means only TLS 1.0
+			 *
+			 * We want the negotiation, so we'll force it below ...
+			 */
+			$method = is_php('5.6')
+				? STREAM_CRYPTO_METHOD_TLSv1_0_CLIENT | STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT | STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT
+				: STREAM_CRYPTO_METHOD_TLS_CLIENT;
+			$crypto = stream_socket_enable_crypto($this->_smtp_connect, TRUE, $method);
 
 			if ($crypto !== TRUE)
 			{