auth: Empty schemes cannot be aliases

Optimizes cases where empty scheme is compared to PLAIN

diff --git a/src/auth/password-scheme.c b/src/auth/password-scheme.c
index f64cbcbbc933064d2f5f5d27bb71f820903fa843..ea9454e517bfee4aa0f68682471cb6be73c6a648 100644 (file)
--- a/src/auth/password-scheme.c
+++ b/src/auth/password-scheme.c
@@ -262,6 +262,9 @@ bool password_scheme_is_alias(const char *scheme1, const char *scheme2)
 {
        const struct password_scheme *s1 = NULL, *s2 = NULL;
 
+       if (*scheme1 == '\0' || *scheme2 == '\0')
+               return FALSE;
+
        scheme1 = t_strcut(scheme1, '.');
        scheme2 = t_strcut(scheme2, '.');