RE: [PATCH net] net: ieee802154: adf7242: Fix some potential buffer overflow in adf7242_stats_show()

[Hennerich, Michael]

> -----Original Message-----
> From: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> Sent: Samstag, 21. Oktober 2023 20:04
> To: keescook@xxxxxxxxxxxx; Hennerich, Michael
> <Michael.Hennerich@xxxxxxxxxx>; Alexander Aring <alex.aring@xxxxxxxxx>;
> Stefan Schmidt <stefan@xxxxxxxxxxxxxxxxxx>; Miquel Raynal
> <miquel.raynal@xxxxxxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>; Eric
> Dumazet <edumazet@xxxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx>; Paolo
> Abeni <pabeni@xxxxxxxxxx>; Marcel Holtmann <marcel@xxxxxxxxxxxx>
> Cc: linux-hardening@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; kernel-
> janitors@xxxxxxxxxxxxxxx; Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>;
> Stefan Schmidt <stefan@xxxxxxxxxxxxxxx>; linux-wpan@xxxxxxxxxxxxxxx;
> netdev@xxxxxxxxxxxxxxx
> Subject: [PATCH net] net: ieee802154: adf7242: Fix some potential buffer
> overflow in adf7242_stats_show()
> 
> 
> strncat() usage in adf7242_debugfs_init() is wrong.
> The size given to strncat() is the maximum number of bytes that can be written,
> excluding the trailing NULL.
> 
> Here, the size that is passed, DNAME_INLINE_LEN, does not take into account
> the size of "adf7242-" that is already in the array.
> 
> In order to fix it, use snprintf() instead.
> 
> Fixes: 7302b9d90117 ("ieee802154/adf7242: Driver for ADF7242 MAC
> IEEE802154")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> ---

Acked-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx>

>  drivers/net/ieee802154/adf7242.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ieee802154/adf7242.c
> b/drivers/net/ieee802154/adf7242.c
> index a03490ba2e5b..cc7ddc40020f 100644
> --- a/drivers/net/ieee802154/adf7242.c
> +++ b/drivers/net/ieee802154/adf7242.c
> @@ -1162,9 +1162,10 @@ static int adf7242_stats_show(struct seq_file *file,
> void *offset)
> 
>  static void adf7242_debugfs_init(struct adf7242_local *lp)  {
> -	char debugfs_dir_name[DNAME_INLINE_LEN + 1] = "adf7242-";
> +	char debugfs_dir_name[DNAME_INLINE_LEN + 1];
> 
> -	strncat(debugfs_dir_name, dev_name(&lp->spi->dev),
> DNAME_INLINE_LEN);
> +	snprintf(debugfs_dir_name, sizeof(debugfs_dir_name),
> +		 "adf7242-%s", dev_name(&lp->spi->dev));
> 
>  	lp->debugfs_root = debugfs_create_dir(debugfs_dir_name, NULL);
> 
> --
> 2.34.1