syzbot reported shift-out-of-bounds in nl802154_new_interface. The problem was in signed representation of enum nl802154_iftype enum nl802154_iftype { /* for backwards compatibility TODO */ NL802154_IFTYPE_UNSPEC = -1, ... Since, enum has negative value in it, objects of this type will be represented as signed integer. type = nla_get_u32(info->attrs[NL802154_ATTR_IFTYPE]); u32 will be casted to signed, which can cause negative value type. Reported-by: syzbot+7bf7b22759195c9a21e9@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx> --- net/ieee802154/nl802154.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ieee802154/nl802154.c b/net/ieee802154/nl802154.c index 7c5a1aa5adb4..6cce045e3d40 100644 --- a/net/ieee802154/nl802154.c +++ b/net/ieee802154/nl802154.c @@ -910,7 +910,7 @@ static int nl802154_new_interface(struct sk_buff *skb, struct genl_info *info) if (info->attrs[NL802154_ATTR_IFTYPE]) { type = nla_get_u32(info->attrs[NL802154_ATTR_IFTYPE]); - if (type > NL802154_IFTYPE_MAX || + if (type > NL802154_IFTYPE_MAX || type < 0 || !(rdev->wpan_phy.supported.iftypes & BIT(type))) return -EINVAL; } -- 2.30.2