Re: [PATCH] net: tun: replace strcpy with strscpy for ifr_name
From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Date: 2025-08-11 14:27:50
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[PATCH net-next] Miguel García wrote:
Replace the strcpy() calls that copy the device name into ifr->ifr_name with strscpy() to avoid potential overflows and guarantee NUL termination.
NULL
quoted hunk ↗ jump to hunk
Destination is ifr->ifr_name (size IFNAMSIZ). Tested in QEMU (BusyBox rootfs): - Created TUN devices via TUNSETIFF helper - Set addresses and brought links up - Verified long interface names are safely truncated (IFNAMSIZ-1) Signed-off-by: Miguel García <redacted> --- drivers/net/tun.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)diff --git a/drivers/net/tun.c b/drivers/net/tun.c index f8c5e2fd04df..e4c6c1118acb 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c@@ -2800,13 +2800,13 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) if (netif_running(tun->dev)) netif_tx_wake_all_queues(tun->dev); - strcpy(ifr->ifr_name, tun->dev->name); + strscpy(ifr->ifr_name, tun->dev->name, IFNAMSIZ);
Since both dst and src are arrays of IFNAMSIZ, can drop the third argument. Then it is inferred from the field sizes, which is more robust.
return 0;
}
static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
{
- strcpy(ifr->ifr_name, tun->dev->name);
+ strscpy(ifr->ifr_name, tun->dev->name, IFNAMSIZ);
ifr->ifr_flags = tun_flags(tun);
--
2.34.1