--- php-7.1.22.org/ext/standard/mail.c	2018-09-11 16:08:35.000000000 +0200
+++ php-7.1.22/ext/standard/mail.c	2018-09-14 11:40:47.086119608 +0200
@@ -46,6 +46,8 @@
 #include "php_ini.h"
 #include "php_string.h"
 #include "exec.h"
+#include "zend_operators.h"
+#include "zend_globals.h"
 
 #ifdef PHP_WIN32
 #include "win32/sendmail.h"
@@ -125,6 +127,18 @@ PHP_FUNCTION(mail)
 		MAIL_ASCIIZ_CHECK(ZSTR_VAL(extra_cmd), ZSTR_LEN(extra_cmd));
 	}
 
+    /* search for To: and Subject: headers which should be specified in proper mail() parameters, not in additional headers */
+    if (headers != NULL) {
+        if (strncasecmp(headers, "to:", sizeof("to:") - 1) == 0 || strcasestr(headers, "\nto:")) {
+            php_error_docref(NULL TSRMLS_CC, E_WARNING, "To: headers aren't allowed in the additional_headers parameter. Use $to parameter for that. Mail not sent.");
+            RETURN_FALSE;
+        }
+        if (strncasecmp(headers, "subject:", sizeof("subject:") - 1) == 0 || strcasestr(headers, "\nsubject:")) {
+            php_error_docref(NULL TSRMLS_CC, E_WARNING, "Subject: headers aren't allowed in the additional_headers parameter. Use $subject parameter for that. Mail not sent.");
+            RETURN_FALSE;
+        }
+    }
+
 	if (to_len > 0) {
 		to_r = estrndup(to, to_len);
 		for (; to_len; to_len--) {
@@ -397,8 +411,42 @@ PHPAPI int php_mail(char *to, char *subj
 			MAIL_RET(0);
 		}
 #endif
-		fprintf(sendmail, "To: %s\n", to);
-		fprintf(sendmail, "Subject: %s\n", subject);
+		TSRMLS_FETCH();
+
+		if ((to != NULL) && (strlen(to)!=0)) {
+			fprintf(sendmail, "To: %s\n", to);
+		}
+		if ((subject != NULL) && (strlen(subject)!=0)) {
+			fprintf(sendmail, "Subject: %s\n", subject);
+		}
+		if (Z_TYPE(PG(http_globals)[TRACK_VARS_SERVER]) == IS_ARRAY
+				|| zend_is_auto_global_str(ZEND_STRL("_SERVER"))) {
+					zval *remote_addr, *server_name, *server_port, *script_name, *http_user_agent;
+					remote_addr = zend_hash_str_find(Z_ARRVAL_P(&PG(http_globals)[TRACK_VARS_SERVER]),
+							"REMOTE_ADDR", sizeof("REMOTE_ADDR")-1);
+					server_name = zend_hash_str_find(Z_ARRVAL_P(&PG(http_globals)[TRACK_VARS_SERVER]),
+							"SERVER_NAME", sizeof("SERVER_NAME")-1);
+					server_port = zend_hash_str_find(Z_ARRVAL_P(&PG(http_globals)[TRACK_VARS_SERVER]),
+							"SERVER_PORT", sizeof("SERVER_PORT")-1);
+					script_name = zend_hash_str_find(Z_ARRVAL_P(&PG(http_globals)[TRACK_VARS_SERVER]),
+							"SCRIPT_NAME", sizeof("SCRIPT_NAME")-1);
+					http_user_agent = zend_hash_str_find(Z_ARRVAL_P(&PG(http_globals)[TRACK_VARS_SERVER]),
+							"HTTP_USER_AGENT", sizeof("HTTP_USER_AGENT")-1);
+
+					if (remote_addr && Z_TYPE_P(remote_addr) == IS_STRING)
+						fprintf(sendmail, "HTTP-Posting-Client: %s\n", Z_STRVAL_P(remote_addr));
+					if (server_name && Z_TYPE_P(server_name) == IS_STRING) {
+						fprintf(sendmail, "HTTP-Posting-URI: %s", Z_STRVAL_P(server_name));
+						if (server_port && Z_TYPE_P(server_port) == IS_STRING)
+							fprintf(sendmail, ":%s", Z_STRVAL_P(server_port));
+						if (script_name && Z_TYPE_P(script_name) == IS_STRING)
+							fprintf(sendmail, "%s", Z_STRVAL_P(script_name));
+						fprintf(sendmail, "\n");
+					}
+					if (http_user_agent && Z_TYPE_P(http_user_agent) == IS_STRING)
+						fprintf(sendmail, "HTTP-Posting-User-Agent: %s\n", Z_STRVAL_P(http_user_agent));
+		}
+
 		if (hdr != NULL) {
 			fprintf(sendmail, "%s\n", hdr);
 		}