i40e: Add checking for null for nlmsg_find_attr()

[ Upstream commit 7fa0b526f865cb42aa33917fd02a92cb03746f4d ]

The result of nlmsg_find_attr() 'br_spec' is dereferenced in
nla_for_each_nested(), but it can take NULL value in nla_find() function,
which will result in an error.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 51616018dd1b ("i40e: Add support for getlink, setlink ndo ops")
Signed-off-by: Natalia Petrova <n.petrova@fintech.ru>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Link: https://lore.kernel.org/r/20230209172833.3596034-1-anthony.l.nguyen@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 18044c2..d30bc38 100644 (file)
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -13140,6 +13140,8 @@ static int i40e_ndo_bridge_setlink(struct net_device *dev,
        }
 
        br_spec = nlmsg_find_attr(nlh, sizeof(struct ifinfomsg), IFLA_AF_SPEC);
+       if (!br_spec)
+               return -EINVAL;
 
        nla_for_each_nested(attr, br_spec, rem) {
                __u16 mode;