tsrm_win32_get_path_sid_key might returns NULL (Partially fix bug #71752)

cherry-picked from 7d5f71b0b125c89211e5a2a6d925deba938abd41

diff --git a/Zend/zend_virtual_cwd.c b/Zend/zend_virtual_cwd.c
index 32d6ab8f8570922da317fb181e94e89ff47ddbe7..512a3037615b5585fc98e29fd2e71bc6b12d5151 100644 (file)
--- a/Zend/zend_virtual_cwd.c
+++ b/Zend/zend_virtual_cwd.c
@@ -587,12 +587,14 @@ static inline unsigned long realpath_cache_key(const char *path, int path_len TS
        register unsigned long h;
        char *bucket_key_start = tsrm_win32_get_path_sid_key(path TSRMLS_CC);
        char *bucket_key = (char *)bucket_key_start;
-       const char *e = bucket_key + strlen(bucket_key);
+       const char *e;
 
        if (!bucket_key) {
                return 0;
        }
 
+       e = bucket_key + strlen(bucket_key);
+
        for (h = 2166136261U; bucket_key < e;) {
                h *= 16777619;
                h ^= *bucket_key++;