Fix phpGH-18986: OpenSSL backend: incorrect RAND_{load,write}_file() return value check

As noted by the LibreSSL maintainer, these functions return -1 on error.
This is further confirmed by my static analyzer that inferred the same
thing for OpenSSL.

Closes phpGH-19013.

Author: ndossche

NEWS

@@ -37,6 +37,8 @@ PHP                                                                        NEWS
 - OpenSSL:
   . Fixed bug #80770 (It is not possible to get client peer certificate with
     stream_socket_server). (Jakub Zelenka)
+  . Fixed bug GH-18986 (OpenSSL backend: incorrect RAND_{load,write}_file()
+    return value check). (nielsdos, botovq)
 
 - PCNTL:
   . Fixed bug GH-18958 (Fatal error during shutdown after pcntl_rfork() or

ext/openssl/openssl.c

@@ -1095,7 +1095,7 @@ static int php_openssl_load_rand_file(const char * file, int *egdsocket, int *se
 		return SUCCESS;
 #endif
 	}
-	if (file == NULL || !RAND_load_file(file, -1)) {
+	if (file == NULL || RAND_load_file(file, -1) < 0) {
 		if (RAND_status() == 0) {
 			php_openssl_store_errors();
 			php_error_docref(NULL, E_WARNING, "Unable to load random state; not enough random data!");
@@ -1122,7 +1122,7 @@ static int php_openssl_write_rand_file(const char * file, int egdsocket, int see
 		file = RAND_file_name(buffer, sizeof(buffer));
 	}
 	PHP_OPENSSL_RAND_ADD_TIME();
-	if (file == NULL || !RAND_write_file(file)) {
+	if (file == NULL || RAND_write_file(file) < 0) {
 		php_openssl_store_errors();
 		php_error_docref(NULL, E_WARNING, "Unable to write random state");
 		return FAILURE;