net/ncsi: prevent a couple array underflows

We recently refactored this code and introduced a static checker
warning.  Smatch complains that if cmd->index is zero then we would
underflow the arrays.  That's obviously true.

The question is whether we prevent cmd->index from being zero at a
different level.  I've looked at the code and I don't immediately see
a check for that.

Fixes: 062b3e1b6d ("net/ncsi: Refactor MAC, VLAN filters")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Dan Carpenter 2018-05-17 15:33:36 +03:00 committed by David S. Miller
parent be7f3e5999
commit 990a9d4975

View File

@ -347,7 +347,7 @@ static int ncsi_rsp_handler_svf(struct ncsi_request *nr)
cmd = (struct ncsi_cmd_svf_pkt *)skb_network_header(nr->cmd);
ncf = &nc->vlan_filter;
if (cmd->index > ncf->n_vids)
if (cmd->index == 0 || cmd->index > ncf->n_vids)
return -ERANGE;
/* Add or remove the VLAN filter. Remember HW indexes from 1 */
@ -445,7 +445,8 @@ static int ncsi_rsp_handler_sma(struct ncsi_request *nr)
ncf = &nc->mac_filter;
bitmap = &ncf->bitmap;
if (cmd->index > ncf->n_uc + ncf->n_mc + ncf->n_mixed)
if (cmd->index == 0 ||
cmd->index > ncf->n_uc + ncf->n_mc + ncf->n_mixed)
return -ERANGE;
index = (cmd->index - 1) * ETH_ALEN;