[PATCH 5.8 38/70] ibmvnic: fix ibmvnic_set_mac

[Greg Kroah-Hartman]

From: Lijun Pan <l...@linux.ibm.com>

[ Upstream commit 8fc3672a8ad3e782bac80e979bc2a2c10960cbe9 ]

Jakub Kicinski brought up a concern in ibmvnic_set_mac().
ibmvnic_set_mac() does this:

        ether_addr_copy(adapter->mac_addr, addr->sa_data);
        if (adapter->state != VNIC_PROBED)
                rc = __ibmvnic_set_mac(netdev, addr->sa_data);

So if state == VNIC_PROBED, the user can assign an invalid address to
adapter->mac_addr, and ibmvnic_set_mac() will still return 0.

The fix is to validate ethernet address at the beginning of
ibmvnic_set_mac(), and move the ether_addr_copy to
the case of "adapter->state != VNIC_PROBED".

Fixes: c26eba03e407 ("ibmvnic: Update reset infrastructure to support tunable 
parameters")
Signed-off-by: Lijun Pan <l...@linux.ibm.com>
Link: https://lore.kernel.org/r/20201027220456.71450-1-...@linux.ibm.com
Signed-off-by: Jakub Kicinski <k...@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/net/ethernet/ibm/ibmvnic.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -1828,9 +1828,13 @@ static int ibmvnic_set_mac(struct net_de
        int rc;
 
        rc = 0;
-       ether_addr_copy(adapter->mac_addr, addr->sa_data);
-       if (adapter->state != VNIC_PROBED)
+       if (!is_valid_ether_addr(addr->sa_data))
+               return -EADDRNOTAVAIL;
+
+       if (adapter->state != VNIC_PROBED) {
+               ether_addr_copy(adapter->mac_addr, addr->sa_data);
                rc = __ibmvnic_set_mac(netdev, addr->sa_data);
+       }
 
        return rc;
 }