hwmon: corsair-psu: fix possible out-of-bounds access on missing string termination

[PATCH] hwmon: corsair-psu: fix possible out-of-bounds access on missing string termination

Posted by Wilken Gottwalt 1 month, 3 weeks ago

In theory it could be possible that the REPLY_SIZE sized buffers for
holding the vendor and product strings could be end up missing the null
termination (for example by malicious hardware built on purpose)
required by the seq_printf() call. That limits the debugfs printf calls
to a maximum string length of REPLY_SIZE.

Fixes: d115b51e0e567 ("hwmon: add Corsair PSU HID controller driver")
Signed-off-by: Wilken Gottwalt <wilken.gottwalt@posteo.net>
---
 drivers/hwmon/corsair-psu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/corsair-psu.c b/drivers/hwmon/corsair-psu.c
index ce958cdaef58..3cb0ba592250 100644
--- a/drivers/hwmon/corsair-psu.c
+++ b/drivers/hwmon/corsair-psu.c
@@ -701,7 +701,7 @@ static int vendor_show(struct seq_file *seqf, void *unused)
 {
 	struct corsairpsu_data *priv = seqf->private;
 
-	seq_printf(seqf, "%s\n", priv->vendor);
+	seq_printf(seqf, "%.*s\n", REPLY_SIZE, priv->vendor);
 
 	return 0;
 }
@@ -711,7 +711,7 @@ static int product_show(struct seq_file *seqf, void *unused)
 {
 	struct corsairpsu_data *priv = seqf->private;
 
-	seq_printf(seqf, "%s\n", priv->product);
+	seq_printf(seqf, "%.*s\n", REPLY_SIZE, priv->product);
 
 	return 0;
 }
-- 
2.55.0

Re: [PATCH] hwmon: corsair-psu: fix possible out-of-bounds access on missing string termination

Posted by Guenter Roeck 1 month, 3 weeks ago

On Wed, Aug 05, 2026 at 07:19:20AM +0000, Wilken Gottwalt wrote:
> In theory it could be possible that the REPLY_SIZE sized buffers for
> holding the vendor and product strings could be end up missing the null
> termination (for example by malicious hardware built on purpose)
> required by the seq_printf() call. That limits the debugfs printf calls
> to a maximum string length of REPLY_SIZE.
> 
> Fixes: d115b51e0e567 ("hwmon: add Corsair PSU HID controller driver")
> Signed-off-by: Wilken Gottwalt <wilken.gottwalt@posteo.net>

Applied.

Thanks,
Guenter