From: Peng Jiang <jiang.peng9@xxxxxxxxxx>
Building with W=1 triggers format-truncation warnings in the
register_vlan_device function when compiled with GCC 12.3.0.
These warnings occur due to the use of %i and %.4i format
specifiers with a buffer size that might be insufficient
for the formatted string, potentially causing truncation.
The original warning trace:
net/8021q/vlan.c:247:17: note: 'snprintf' output between 3 and 22 bytes into a destination of size 16
247 | snprintf(name, IFNAMSIZ, "%s.%i", real_dev->name, vlan_id);
Signed-off-by: Peng Jiang <jiang.peng9@xxxxxxxxxx>
---
net/8021q/vlan.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
index 06908e37c3d9..f2c17035f625 100644
--- a/net/8021q/vlan.c
+++ b/net/8021q/vlan.c
@@ -217,7 +217,7 @@ static int register_vlan_device(struct net_device *real_dev, u16 vlan_id)
struct vlan_dev_priv *vlan;
struct net *net = dev_net(real_dev);
struct vlan_net *vn = net_generic(net, vlan_net_id);
- char name[IFNAMSIZ];
+ char name[IFNAMSIZ + 6]; /* plus extra 6 bytes for vlan_id */
int err;
if (vlan_id >= VLAN_VID_MASK)
@@ -232,26 +232,26 @@ static int register_vlan_device(struct net_device *real_dev, u16 vlan_id)
switch (vn->name_type) {
case VLAN_NAME_TYPE_RAW_PLUS_VID:
/* name will look like: eth1.0005 */
- snprintf(name, IFNAMSIZ, "%s.%.4i", real_dev->name, vlan_id);
+ snprintf(name, sizeof(name), "%s.%.4i", real_dev->name, vlan_id);
break;
case VLAN_NAME_TYPE_PLUS_VID_NO_PAD:
/* Put our vlan.VID in the name.
* Name will look like: vlan5
*/
- snprintf(name, IFNAMSIZ, "vlan%i", vlan_id);
+ snprintf(name, sizeof(name), "vlan%i", vlan_id);
break;
case VLAN_NAME_TYPE_RAW_PLUS_VID_NO_PAD:
/* Put our vlan.VID in the name.
* Name will look like: eth0.5
*/
- snprintf(name, IFNAMSIZ, "%s.%i", real_dev->name, vlan_id);
+ snprintf(name, sizeof(name), "%s.%i", real_dev->name, vlan_id);
break;
case VLAN_NAME_TYPE_PLUS_VID:
/* Put our vlan.VID in the name.
* Name will look like: vlan0005
*/
default:
- snprintf(name, IFNAMSIZ, "vlan%.4i", vlan_id);
+ snprintf(name, sizeof(name), "vlan%.4i", vlan_id);
}
new_dev = alloc_netdev(sizeof(struct vlan_dev_priv), name,
--
2.25.1