`strncpy` is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.
We should NUL-pad as there are full struct copies happening in places:
| case NL80211_IFTYPE_MONITOR:
| ret = rtw_cfg80211_add_monitor_if(padapter,
| (char *)name, &ndev);
| break;
A suitable replacement is `strscpy_pad` due to the fact that it
guarantees both NUL-termination and NUL-padding on the destination
buffer.
Additionally, replace size macro `IFNAMSIZ` with sizeof():
| struct net_device {
| char name[IFNAMSIZ];
| ...
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Signed-off-by: xueqin Luo <[email protected]>
---
drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c b/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
index 1ff763c10064..90d521571f0e 100644
--- a/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
+++ b/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
@@ -2144,8 +2144,7 @@ static int rtw_cfg80211_add_monitor_if(struct adapter *padapter, char *name, str
}
mon_ndev->type = ARPHRD_IEEE80211_RADIOTAP;
- strncpy(mon_ndev->name, name, IFNAMSIZ);
- mon_ndev->name[IFNAMSIZ - 1] = 0;
+ strscpy_pad(mon_ndev->name, name, sizeof(mon_ndev->name));
mon_ndev->needs_free_netdev = true;
mon_ndev->priv_destructor = rtw_ndev_destructor;
--
2.34.1
On Wed, Dec 13, 2023 at 09:18:40AM +0800, xueqin Luo wrote:
> `strncpy` is deprecated for use on NUL-terminated destination strings
> [1] and as such we should prefer more robust and less ambiguous string
> interfaces.
>
> We should NUL-pad as there are full struct copies happening in places:
> | case NL80211_IFTYPE_MONITOR:
> | ret = rtw_cfg80211_add_monitor_if(padapter,
> | (char *)name, &ndev);
> | break;
>
I don't see where the full copy is... What you're looking for is some
place that copies "mon_ndev->name" to the user.
> A suitable replacement is `strscpy_pad` due to the fact that it
> guarantees both NUL-termination and NUL-padding on the destination
> buffer.
>
> Additionally, replace size macro `IFNAMSIZ` with sizeof():
> | struct net_device {
> | char name[IFNAMSIZ];
> | ...
This would normally be the right move but IFNAMSIZ is a really standard
macro that everyone knows.
When I'm reviewing this code, I later on see a line:
memcpy(pwdev_priv->ifname_mon, name, IFNAMSIZ + 1);
That means name must be "IFNAMSIZ + 1" characters long or it is a bug.
Please find out where name is set. We need to know how long it is
before we can go any further.
regards,
dan carpenter