qapi: Assert non-input visitors see only valid narrow integers

visit_type_intN() and visit_type_uintN() fail when the value is out of
bounds.

This is appropriate with an input visitor: the value comes from input,
and input may be bad.

It should never happen with the other visitors: the value comes from
the caller, and callers must keep it within bounds.  Assert that.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200424084338.26803-10-armbru@redhat.com>

diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
index 80ca83bcb9188ec4cfe48761de778a4009d7e3d2..74aa9c04bd3daa359270ea68e56d77a996444995 100644 (file)
--- a/qapi/qapi-visit-core.c
+++ b/qapi/qapi-visit-core.c
@@ -160,10 +160,13 @@ static void visit_type_uintN(Visitor *v, uint64_t *obj, const char *name,
     Error *err = NULL;
     uint64_t value = *obj;
 
+    assert(v->type == VISITOR_INPUT || value <= max);
+
     v->type_uint64(v, name, &value, &err);
     if (err) {
         error_propagate(errp, err);
     } else if (value > max) {
+        assert(v->type == VISITOR_INPUT);
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
                    name ? name : "null", type);
     } else {
@@ -219,10 +222,13 @@ static void visit_type_intN(Visitor *v, int64_t *obj, const char *name,
     Error *err = NULL;
     int64_t value = *obj;
 
+    assert(v->type == VISITOR_INPUT || (value >= min && value <= max));
+
     v->type_int64(v, name, &value, &err);
     if (err) {
         error_propagate(errp, err);
     } else if (value < min || value > max) {
+        assert(v->type == VISITOR_INPUT);
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
                    name ? name : "null", type);
     } else {