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

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

[Christophe JAILLET]

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@wanadoo.fr>
---
 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

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

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:

On Sat, 21 Oct 2023 20:03:53 +0200 you wrote:
> 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.
> 
> [...]

Here is the summary with links:
  - [net] net: ieee802154: adf7242: Fix some potential buffer overflow in adf7242_stats_show()
    https://git.kernel.org/netdev/net/c/ca082f019d8f

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

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

[Hennerich, Michael]

> -----Original Message-----
> From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> Sent: Samstag, 21. Oktober 2023 20:04
> To: keescook@chromium.org; Hennerich, Michael
> <Michael.Hennerich@analog.com>; Alexander Aring <alex.aring@gmail.com>;
> Stefan Schmidt <stefan@datenfreihafen.org>; Miquel Raynal
> <miquel.raynal@bootlin.com>; David S. Miller <davem@davemloft.net>; Eric
> Dumazet <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo
> Abeni <pabeni@redhat.com>; Marcel Holtmann <marcel@holtmann.org>
> Cc: linux-hardening@vger.kernel.org; linux-kernel@vger.kernel.org; kernel-
> janitors@vger.kernel.org; Christophe JAILLET <christophe.jaillet@wanadoo.fr>;
> Stefan Schmidt <stefan@osg.samsung.com>; linux-wpan@vger.kernel.org;
> netdev@vger.kernel.org
> 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@wanadoo.fr>
> ---

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

>  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