krb5: Make FILE ccache type a collection type!

lib/krb5/cache.c

@@ -410,9 +410,22 @@ krb5_cc_resolve_for(krb5_context context,
     ret = krb5_unparse_name(context, principal, &p);
     if (ret)
         return ret;
-    /* Subsidiary components cannot have ':'s in them */
-    for (s = strchr(p, ':'); s; s = strchr(s + 1, ':'))
-        *s = '-';
+    /*
+     * Subsidiary components cannot have various chars in them that are used as
+     * separators.  ':' is used for subsidiary separators in all ccache types
+     * except FILE, where '+' is used instead because we can't use ':' in file
+     * paths on Windows and because ':' is not in the POSIX safe set.
+     */
+    for (s = p; *s; s++) {
+        switch (s[0]) {
+        case ':':
+        case '+':
+        case '/':
+        case '\\':
+            s[0] = '-';
+        default: break;
+        }
+    }
     ret = krb5_cc_resolve_sub(context, cctype, name, p, id);
     free(p);
     return ret;