net: mlx4: Use scnprintf() for avoiding potential buffer overflow

Since snprintf() returns the would-be-output size instead of the
actual output size, the succeeding calls may go beyond the given
buffer limit.  Fix it by replacing with scnprintf().

Cc: "David S . Miller" <davem@davemloft.net>
Cc: Tariq Toukan <tariqt@mellanox.com>
To: netdev@vger.kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlx4/mcg.c b/drivers/net/ethernet/mellanox/mlx4/mcg.c
index 9c48182..9486cae 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx4/mcg.c
+++ b/drivers/net/ethernet/mellanox/mlx4/mcg.c
@@ -906,59 +906,59 @@ static void mlx4_err_rule(struct mlx4_dev *dev, char *str,
        int len = 0;
 
        mlx4_err(dev, "%s", str);
-       len += snprintf(buf + len, BUF_SIZE - len,
-                       "port = %d prio = 0x%x qp = 0x%x ",
-                       rule->port, rule->priority, rule->qpn);
+       len += scnprintf(buf + len, BUF_SIZE - len,
+                        "port = %d prio = 0x%x qp = 0x%x ",
+                        rule->port, rule->priority, rule->qpn);
 
        list_for_each_entry(cur, &rule->list, list) {
                switch (cur->id) {
                case MLX4_NET_TRANS_RULE_ID_ETH:
-                       len += snprintf(buf + len, BUF_SIZE - len,
-                                       "dmac = %pM ", &cur->eth.dst_mac);
+                       len += scnprintf(buf + len, BUF_SIZE - len,
+                                        "dmac = %pM ", &cur->eth.dst_mac);
                        if (cur->eth.ether_type)
-                               len += snprintf(buf + len, BUF_SIZE - len,
-                                               "ethertype = 0x%x ",
-                                               be16_to_cpu(cur->eth.ether_type));
+                               len += scnprintf(buf + len, BUF_SIZE - len,
+                                                "ethertype = 0x%x ",
+                                                be16_to_cpu(cur->eth.ether_type));
                        if (cur->eth.vlan_id)
-                               len += snprintf(buf + len, BUF_SIZE - len,
-                                               "vlan-id = %d ",
-                                               be16_to_cpu(cur->eth.vlan_id));
+                               len += scnprintf(buf + len, BUF_SIZE - len,
+                                                "vlan-id = %d ",
+                                                be16_to_cpu(cur->eth.vlan_id));
                        break;
 
                case MLX4_NET_TRANS_RULE_ID_IPV4:
                        if (cur->ipv4.src_ip)
-                               len += snprintf(buf + len, BUF_SIZE - len,
-                                               "src-ip = %pI4 ",
-                                               &cur->ipv4.src_ip);
+                               len += scnprintf(buf + len, BUF_SIZE - len,
+                                                "src-ip = %pI4 ",
+                                                &cur->ipv4.src_ip);
                        if (cur->ipv4.dst_ip)
-                               len += snprintf(buf + len, BUF_SIZE - len,
-                                               "dst-ip = %pI4 ",
-                                               &cur->ipv4.dst_ip);
+                               len += scnprintf(buf + len, BUF_SIZE - len,
+                                                "dst-ip = %pI4 ",
+                                                &cur->ipv4.dst_ip);
                        break;
 
                case MLX4_NET_TRANS_RULE_ID_TCP:
                case MLX4_NET_TRANS_RULE_ID_UDP:
                        if (cur->tcp_udp.src_port)
-                               len += snprintf(buf + len, BUF_SIZE - len,
-                                               "src-port = %d ",
-                                               be16_to_cpu(cur->tcp_udp.src_port));
+                               len += scnprintf(buf + len, BUF_SIZE - len,
+                                                "src-port = %d ",
+                                                be16_to_cpu(cur->tcp_udp.src_port));
                        if (cur->tcp_udp.dst_port)
-                               len += snprintf(buf + len, BUF_SIZE - len,
-                                               "dst-port = %d ",
-                                               be16_to_cpu(cur->tcp_udp.dst_port));
+                               len += scnprintf(buf + len, BUF_SIZE - len,
+                                                "dst-port = %d ",
+                                                be16_to_cpu(cur->tcp_udp.dst_port));
                        break;
 
                case MLX4_NET_TRANS_RULE_ID_IB:
-                       len += snprintf(buf + len, BUF_SIZE - len,
-                                       "dst-gid = %pI6\n", cur->ib.dst_gid);
-                       len += snprintf(buf + len, BUF_SIZE - len,
-                                       "dst-gid-mask = %pI6\n",
-                                       cur->ib.dst_gid_msk);
+                       len += scnprintf(buf + len, BUF_SIZE - len,
+                                        "dst-gid = %pI6\n", cur->ib.dst_gid);
+                       len += scnprintf(buf + len, BUF_SIZE - len,
+                                        "dst-gid-mask = %pI6\n",
+                                        cur->ib.dst_gid_msk);
                        break;
 
                case MLX4_NET_TRANS_RULE_ID_VXLAN:
-                       len += snprintf(buf + len, BUF_SIZE - len,
-                                       "VNID = %d ", be32_to_cpu(cur->vxlan.vni));
+                       len += scnprintf(buf + len, BUF_SIZE - len,
+                                        "VNID = %d ", be32_to_cpu(cur->vxlan.vni));
                        break;
                case MLX4_NET_TRANS_RULE_ID_IPV6:
                        break;
@@ -967,7 +967,7 @@ static void mlx4_err_rule(struct mlx4_dev *dev, char *str,
                        break;
                }
        }
-       len += snprintf(buf + len, BUF_SIZE - len, "\n");
+       len += scnprintf(buf + len, BUF_SIZE - len, "\n");
        mlx4_err(dev, "%s", buf);
 
        if (len >= BUF_SIZE)