Fix GH-8086: Introduce mail.mixed_lf_and_crlf INI

When this INI option is enabled, it reverts the line separator for
headers and message to LF which was a non conformant behavior in PHP 7.
It is done because some non conformant MTAs fail to parse CRLF line
separator for headers and body.

Author: bukka

ext/standard/mail.c

@@ -429,14 +429,16 @@ PHPAPI int php_mail(const char *to, const char *subject, const char *message, co
 		MAIL_RET(0);
 	}
 
+	char *line_sep = PG(mail_mixed_lf_and_crlf) ? "\n" : "\r\n";
+
 	if (PG(mail_x_header)) {
 		const char *tmp = zend_get_executed_filename();
 		zend_string *f;
 
 		f = php_basename(tmp, strlen(tmp), NULL, 0);
 
 		if (headers != NULL && *headers) {
-			spprintf(&ahdr, 0, "X-PHP-Originating-Script: " ZEND_LONG_FMT ":%s\r\n%s", php_getuid(), ZSTR_VAL(f), headers);
+			spprintf(&ahdr, 0, "X-PHP-Originating-Script: " ZEND_LONG_FMT ":%s%s%s", php_getuid(), ZSTR_VAL(f), line_sep, headers);
 		} else {
 			spprintf(&ahdr, 0, "X-PHP-Originating-Script: " ZEND_LONG_FMT ":%s", php_getuid(), ZSTR_VAL(f));
 		}
@@ -510,12 +512,12 @@ PHPAPI int php_mail(const char *to, const char *subject, const char *message, co
 			MAIL_RET(0);
 		}
 #endif
-		fprintf(sendmail, "To: %s\r\n", to);
-		fprintf(sendmail, "Subject: %s\r\n", subject);
+		fprintf(sendmail, "To: %s%s", to, line_sep);
+		fprintf(sendmail, "Subject: %s%s", subject, line_sep);
 		if (hdr != NULL) {
-			fprintf(sendmail, "%s\r\n", hdr);
+			fprintf(sendmail, "%s%s", hdr, line_sep);
 		}
-		fprintf(sendmail, "\r\n%s\r\n", message);
+		fprintf(sendmail, "%s%s%s", line_sep, message, line_sep);
 		ret = pclose(sendmail);
 
 #if PHP_SIGCHILD

ext/standard/tests/mail/gh8086.phpt

@@ -0,0 +1,18 @@
+--TEST--
+GH-8086 (Mail() function not working correctly in PHP 8.x)
+--INI--
+sendmail_path={MAIL:bug47983.out}
+mail.mixed_lf_and_crlf=on
+--FILE--
+<?php
+var_dump(mail('user@example.com', 'Test Subject', 'A Message', 'KHeaders'));
+$mail = file_get_contents('bug47983.out');
+var_dump(preg_match_all('/(?<!\r)\n/', $mail));
+?>
+--CLEAN--
+<?php
+unlink('bug47983.out');
+?>
+--EXPECT--
+bool(true)
+int(5)

main/main.c

@@ -737,6 +737,7 @@ PHP_INI_BEGIN()
 	PHP_INI_ENTRY("SMTP",						"localhost",PHP_INI_ALL,		NULL)
 	PHP_INI_ENTRY("smtp_port",					"25",		PHP_INI_ALL,		NULL)
 	STD_PHP_INI_BOOLEAN("mail.add_x_header",			"0",		PHP_INI_SYSTEM|PHP_INI_PERDIR,		OnUpdateBool,			mail_x_header,			php_core_globals,	core_globals)
+	STD_PHP_INI_BOOLEAN("mail.mixed_lf_and_crlf",			"0",		PHP_INI_SYSTEM|PHP_INI_PERDIR,		OnUpdateBool,			mail_mixed_lf_and_crlf,			php_core_globals,	core_globals)
 	STD_PHP_INI_ENTRY("mail.log",					NULL,		PHP_INI_SYSTEM|PHP_INI_PERDIR,		OnUpdateMailLog,			mail_log,			php_core_globals,	core_globals)
 	PHP_INI_ENTRY("browscap",					NULL,		PHP_INI_SYSTEM,		OnChangeBrowscap)
 	PHP_INI_ENTRY("memory_limit",				"128M",		PHP_INI_ALL,		OnChangeMemoryLimit)

main/php_globals.h

@@ -153,6 +153,7 @@ struct _php_core_globals {
 	char *request_order;
 
 	bool mail_x_header;
+	bool mail_mixed_lf_and_crlf;
 	char *mail_log;
 
 	bool in_error_log;

php.ini-development

@@ -1095,6 +1095,10 @@ smtp_port = 25
 ; Add X-PHP-Originating-Script: that will include uid of the script followed by the filename
 mail.add_x_header = Off
 
+; Use mixed LF and CRLF line separators to keep compatibility with some
+; RFC 2822 non conformant MTA.
+mail.mixed_lf_and_crlf = Off
+
 ; The path to a log file that will log all mail() calls. Log entries include
 ; the full path of the script, line number, To address and headers.
 ;mail.log =

php.ini-production

@@ -1097,6 +1097,10 @@ smtp_port = 25
 ; Add X-PHP-Originating-Script: that will include uid of the script followed by the filename
 mail.add_x_header = Off
 
+; Use mixed LF and CRLF line separators to keep compatibility with some
+; RFC 2822 non conformant MTA.
+mail.mixed_lf_and_crlf = Off
+
 ; The path to a log file that will log all mail() calls. Log entries include
 ; the full path of the script, line number, To address and headers.
 ;mail.log =