[PATCH v2 1/3] net: ethernet: bcmasp: fix possible OOB write in bcmasp_netfilt_get_all_active()

[Hangyu Hua]

rule_locs is allocated in ethtool_get_rxnfc and the size is determined by
rule_cnt from user space. So rule_cnt needs to be check before using
rule_locs to avoid OOB writing or NULL pointer dereference.

Fixes: c5d511c49587 ("net: bcmasp: Add support for wake on net filters")
Signed-off-by: Hangyu Hua <hbh25y at gmail.com>
---

	v2: use -EMSGSIZE instead of truncating the list sliently.

 drivers/net/ethernet/broadcom/asp2/bcmasp.c         | 9 +++++++--
 drivers/net/ethernet/broadcom/asp2/bcmasp.h         | 4 ++--
 drivers/net/ethernet/broadcom/asp2/bcmasp_ethtool.c | 2 +-
 3 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/asp2/bcmasp.c b/drivers/net/ethernet/broadcom/asp2/bcmasp.c
index d63d321f3e7b..e45e0ae932cc 100644
--- a/drivers/net/ethernet/broadcom/asp2/bcmasp.c
+++ b/drivers/net/ethernet/broadcom/asp2/bcmasp.c
@@ -528,13 +528,16 @@ void bcmasp_netfilt_suspend(struct bcmasp_intf *intf)
 				  ASP_RX_FILTER_BLK_CTRL);
 }
 
-void bcmasp_netfilt_get_all_active(struct bcmasp_intf *intf, u32 *rule_locs,
-				   u32 *rule_cnt)
+int bcmasp_netfilt_get_all_active(struct bcmasp_intf *intf, u32 *rule_locs,
+				  u32 *rule_cnt)
 {
 	struct bcmasp_priv *priv = intf->parent;
 	int j = 0, i;
 
 	for (i = 0; i < NUM_NET_FILTERS; i++) {
+		if (j == *rule_cnt)
+			return -EMSGSIZE;
+
 		if (!priv->net_filters[i].claimed ||
 		    priv->net_filters[i].port != intf->port)
 			continue;
@@ -548,6 +551,8 @@ void bcmasp_netfilt_get_all_active(struct bcmasp_intf *intf, u32 *rule_locs,
 	}
 
 	*rule_cnt = j;
+
+	return 0;
 }
 
 int bcmasp_netfilt_get_active(struct bcmasp_intf *intf)
diff --git a/drivers/net/ethernet/broadcom/asp2/bcmasp.h b/drivers/net/ethernet/broadcom/asp2/bcmasp.h
index 5b512f7f5e94..ec90add6b03e 100644
--- a/drivers/net/ethernet/broadcom/asp2/bcmasp.h
+++ b/drivers/net/ethernet/broadcom/asp2/bcmasp.h
@@ -577,8 +577,8 @@ void bcmasp_netfilt_release(struct bcmasp_intf *intf,
 
 int bcmasp_netfilt_get_active(struct bcmasp_intf *intf);
 
-void bcmasp_netfilt_get_all_active(struct bcmasp_intf *intf, u32 *rule_locs,
-				   u32 *rule_cnt);
+int bcmasp_netfilt_get_all_active(struct bcmasp_intf *intf, u32 *rule_locs,
+				  u32 *rule_cnt);
 
 void bcmasp_netfilt_suspend(struct bcmasp_intf *intf);
 
diff --git a/drivers/net/ethernet/broadcom/asp2/bcmasp_ethtool.c b/drivers/net/ethernet/broadcom/asp2/bcmasp_ethtool.c
index c4f1604d5ab3..ce6a3d56fb23 100644
--- a/drivers/net/ethernet/broadcom/asp2/bcmasp_ethtool.c
+++ b/drivers/net/ethernet/broadcom/asp2/bcmasp_ethtool.c
@@ -335,7 +335,7 @@ static int bcmasp_get_rxnfc(struct net_device *dev, struct ethtool_rxnfc *cmd,
 		err = bcmasp_flow_get(intf, cmd);
 		break;
 	case ETHTOOL_GRXCLSRLALL:
-		bcmasp_netfilt_get_all_active(intf, rule_locs, &cmd->rule_cnt);
+		err = bcmasp_netfilt_get_all_active(intf, rule_locs, &cmd->rule_cnt);
 		cmd->data = NUM_NET_FILTERS;
 		break;
 	default:
-- 
2.34.1