Add new database handle attribute mysql_ssl_cipher

It returns SSL encryption cipher or undef if SSL is not used. It can be
used by application to check if SSL was established or not.

MANIFEST

@@ -72,6 +72,7 @@ t/88async-multi-stmts.t
 t/89async-method-check.t
 t/90utf8_params.t
 t/91errcheck.t
+t/92ssl_connection.t
 t/92ssl_optional.t
 t/92ssl_backronym_vulnerability.t
 t/92ssl_riddle_vulnerability.t

dbdimp.c

@@ -3015,6 +3015,14 @@ SV* dbd_db_FETCH_attrib(SV *dbh, imp_dbh_t *imp_dbh, SV *keysv)
       result= serverinfo ?
         sv_2mortal(newSVpvn(serverinfo, strlen(serverinfo))) : &PL_sv_undef;
     } 
+#if ((MYSQL_VERSION_ID >= 50023 && MYSQL_VERSION_ID < 50100) || MYSQL_VERSION_ID >= 50111)
+    else if (kl == 10 && strEQ(key, "ssl_cipher"))
+    {
+      const char* ssl_cipher = mysql_get_ssl_cipher(imp_dbh->pmysql);
+      result= ssl_cipher ?
+        sv_2mortal(newSVpvn(ssl_cipher, strlen(ssl_cipher))) : &PL_sv_undef;
+    }
+#endif
     else if (kl == 13 && strEQ(key, "serverversion"))
       result= sv_2mortal(my_ulonglong2sv(aTHX_ mysql_get_server_version(imp_dbh->pmysql)));
     else if (strEQ(key, "sock"))

lib/DBD/mysql.pm

@@ -1446,18 +1446,19 @@ handles (read only):
 
   $errno = $dbh->{'mysql_errno'};
   $error = $dbh->{'mysql_error'};
-  $info = $dbh->{'mysql_hostinfo'};
+  $hostinfo = $dbh->{'mysql_hostinfo'};
   $info = $dbh->{'mysql_info'};
   $insertid = $dbh->{'mysql_insertid'};
-  $info = $dbh->{'mysql_protoinfo'};
-  $info = $dbh->{'mysql_serverinfo'};
-  $info = $dbh->{'mysql_stat'};
-  $threadId = $dbh->{'mysql_thread_id'};
+  $protoinfo = $dbh->{'mysql_protoinfo'};
+  $serverinfo = $dbh->{'mysql_serverinfo'};
+  $ssl_cipher = $dbh->{'mysql_ssl_cipher'};
+  $stat = $dbh->{'mysql_stat'};
+  $thread_id = $dbh->{'mysql_thread_id'};
 
 These correspond to mysql_errno(), mysql_error(), mysql_get_host_info(),
 mysql_info(), mysql_insert_id(), mysql_get_proto_info(),
-mysql_get_server_info(), mysql_stat() and mysql_thread_id(),
-respectively.
+mysql_get_server_info(), mysql_stat(), mysql_get_ssl_cipher()
+and mysql_thread_id() respectively.
 
 =over 2
 
@@ -1482,6 +1483,19 @@ against:
 
   50200
 
+=item mysql_ssl_cipher
+
+Returns the SSL encryption cipher used for the given connection to
+the server.  In case SSL encryption was not enabled with C<mysql_ssl>
+or was not established returns undef.
+
+  my $ssl_cipher = $dbh->{mysql_ssl_cipher};
+  if (defined $ssl_cipher) {
+    print "Connection with server is encrypted with cipher: $ssl_cipher\n";
+  } else {
+    print "Connection with server is not encrypted\n";
+  }
+
 =item mysql_dbd_stats
 
   $info_hashref = $dhb->{mysql_dbd_stats};

t/92ssl_connection.t

@@ -0,0 +1,30 @@
+use strict;
+use warnings;
+
+use Test::More;
+use DBI;
+
+use vars qw($test_dsn $test_user $test_password);
+use lib 't', '.';
+require "lib.pl";
+
+my $dbh = DbiTestConnect($test_dsn, $test_user, $test_password, { PrintError => 0, RaiseError => 1 });
+my $have_ssl = eval { $dbh->selectrow_hashref("SHOW VARIABLES WHERE Variable_name = 'have_ssl'") };
+$dbh->disconnect();
+plan skip_all => 'Server does not support SSL connections' unless $have_ssl and $have_ssl->{Value} eq 'YES';
+
+plan tests => 4;
+
+$dbh = DBI->connect($test_dsn, $test_user, $test_password, { PrintError => 0, RaiseError => 0, mysql_ssl => 1, mysql_ssl_optional => 1 });
+ok(defined $dbh, 'DBD::mysql supports mysql_ssl=1 with mysql_ssl_optional=1 and connect to server') or diag('Error code: ' . ($DBI::err || 'none') . "\n" . 'Error message: ' . ($DBI::errstr || 'unknown'));
+
+ok(defined $dbh && defined $dbh->{mysql_ssl_cipher}, 'SSL connection was established') and diag("mysql_ssl_cipher is: ". $dbh->{mysql_ssl_cipher});
+
+$dbh = DBI->connect($test_dsn, $test_user, $test_password, { PrintError => 0, RaiseError => 0, mysql_ssl => 1 });
+if (defined $dbh) {
+  pass('DBD::mysql supports mysql_ssl=1 without mysql_ssl_optional=1 and connect to server');
+  ok(defined $dbh->{mysql_ssl_cipher}, 'SSL connection was established');
+} else {
+  is($DBI::errstr, 'SSL connection error: Enforcing SSL encryption is not supported', 'DBD::mysql supports mysql_ssl=1 without mysql_ssl_optional=1 and fail because cannot enforce SSL encryption') or diag('Error message: ' . ($DBI::errstr || 'unknown'));
+  is($DBI::err, 2026, 'DBD::mysql error code is SSL related') or diag('Error code: ' . ($DBI::err || 'unknown'));
+}