Skip to contentSkip to conversation

net/ncsi: prevent a couple array underflows

PATCH Applied Dan Carpenter 2 participants 2 messages May 17, 2018

Subsystems (4)
Networking Network drivers Kernel janitors Ncsi library
lore
Share & tools
lore

Dan Carpenter

author
#0 lore raw

PATCH 1/1 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 062b3e1b6d4f ("net/ncsi: Refactor MAC, VLAN filters")
Signed-off-by Dan Carpenter <[email protected]>
net/ncsi/ncsi-rsp.c +3 -2
index ce9497966ebe..a6b7c7d5c829 100644
@@ -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;
maintainer Applied
#1 lore raw

From: Dan Carpenter <[email protected]>
Date: Thu, 17 May 2018 15:33:36 +0300

Quoted 10 lines

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 062b3e1b6d4f ("net/ncsi: Refactor MAC, VLAN filters")
Signed-off-by Dan Carpenter <[email protected]>

Applied to net-next, thanks Dan.