Fix #78943: mail() may release string with refcount==1 twice

cmb69 · smalyshev · commit 518a160b65fe · 2019-12-15T13:13:30.000-08:00
Since we need `headers_lc` as well as `headers_trim` in the following,
we do not release the former even if they are the same string, to avoid
complicating the release logic even more.

A new test case is not necessary, since we already have
mail_basic_alt2-win32.phpt and others.
diff --git a/win32/sendmail.c b/win32/sendmail.c
@@ -208,9 +208,6 @@ PHPAPI int TSendMail(char *host, int *error, char **error_message,
 		/* Create a lowercased header for all the searches so we're finally case
 		 * insensitive when searching for a pattern. */
 		headers_lc = zend_string_tolower(headers_trim);
-		if (headers_lc == headers_trim) {
-			zend_string_release_ex(headers_lc, 0);
-		}
 	}
 
 	/* Fall back to sendmail_from php.ini setting */

Original file line number	Diff line number	Diff line change
`@@ -208,9 +208,6 @@ PHPAPI int TSendMail(char host, int error, char **error_message,`
`208`	`208`	`/* Create a lowercased header for all the searches so we're finally case`
`209`	`209`	`* insensitive when searching for a pattern. */`
`210`	`210`	`headers_lc = zend_string_tolower(headers_trim);`
`211`		`- if (headers_lc == headers_trim) {`
`212`		`- zend_string_release_ex(headers_lc, 0);`
`213`		`- }`
`214`	`211`	`}`
`215`	`212`
`216`	`213`	`/* Fall back to sendmail_from php.ini setting */`