2024-06-14 18:04:42

by Dan Carpenter

Subject: [PATCH net] ptp: fix integer overflow in max_vclocks_store

On 32bit systems, the "4 * max" multiply can overflow. Use size_mul()
to fix this.

Fixes: 44c494c8e30e ("ptp: track available ptp vclocks information")
Signed-off-by: Dan Carpenter <[email protected]>
---
drivers/ptp/ptp_sysfs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/ptp/ptp_sysfs.c b/drivers/ptp/ptp_sysfs.c
index a15460aaa03b..bc1562fcd6c9 100644
--- a/drivers/ptp/ptp_sysfs.c
+++ b/drivers/ptp/ptp_sysfs.c
@@ -296,7 +296,7 @@ static ssize_t max_vclocks_store(struct device *dev,
if (max < ptp->n_vclocks)
goto out;

- size = sizeof(int) * max;
+ size = size_mul(sizeof(int), max);
vclock_index = kzalloc(size, GFP_KERNEL);
if (!vclock_index) {
err = -ENOMEM;
--
2.43.0

2024-06-15 17:00:20

by Christophe JAILLET

Subject: Re: [PATCH net] ptp: fix integer overflow in max_vclocks_store

Le 14/06/2024 à 19:31, Dan Carpenter a écrit :
> On 32bit systems, the "4 * max" multiply can overflow. Use size_mul()
> to fix this.
>
> Fixes: 44c494c8e30e ("ptp: track available ptp vclocks information")
> Signed-off-by: Dan Carpenter <[email protected]>
> ---
> drivers/ptp/ptp_sysfs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/ptp/ptp_sysfs.c b/drivers/ptp/ptp_sysfs.c
> index a15460aaa03b..bc1562fcd6c9 100644
> --- a/drivers/ptp/ptp_sysfs.c
> +++ b/drivers/ptp/ptp_sysfs.c
> @@ -296,7 +296,7 @@ static ssize_t max_vclocks_store(struct device *dev,
> if (max < ptp->n_vclocks)
> goto out;
>
> - size = sizeof(int) * max;
> + size = size_mul(sizeof(int), max);
> vclock_index = kzalloc(size, GFP_KERNEL);

kcalloc() maybe?

> if (!vclock_index) {
> err = -ENOMEM;


Unrelated but, a few lines above, should the:
if (max == ptp->max_vclocks)
return count;

be after:
if (mutex_lock_interruptible(&ptp->n_vclocks_mux))
return -ERESTARTSYS;

as done in n_vclocks_store()?

CJ