On Mon, May 05, 2025 at 05:34:15PM +0300, Dan Carpenter wrote:
> The "intf" list iterator is an invalid pointer if the correct
> "intf->intf_num" is not found. Calling atomic_dec(&intf->nr_users) on
> and invalid pointer will lead to memory corruption.
>
> We don't really need to call atomic_dec() if we haven't called
> atomic_add_return() so update the if (intf->in_shutdown) path as well.
Thanks, this is in my tree now.
-corey
>
> Fixes: 8e76741c3d8b ("ipmi: Add a limit on the number of users that may use IPMI")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
> drivers/char/ipmi/ipmi_msghandler.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
> index 8b2c3fca9c4c..064944ae9fdc 100644
> --- a/drivers/char/ipmi/ipmi_msghandler.c
> +++ b/drivers/char/ipmi/ipmi_msghandler.c
> @@ -1240,12 +1240,12 @@ int ipmi_create_user(unsigned int if_num,
> }
> /* Not found, return an error */
> rv = -EINVAL;
> - goto out_kfree;
> + goto out_unlock;
>
> found:
> if (intf->in_shutdown) {
> rv = -ENODEV;
> - goto out_kfree;
> + goto out_unlock;
> }
>
> if (atomic_add_return(1, &intf->nr_users) > max_users) {
> @@ -1293,6 +1293,7 @@ int ipmi_create_user(unsigned int if_num,
> } else {
> *user = new_user;
> }
> +out_unlock:
> mutex_unlock(&ipmi_interfaces_mutex);
> return rv;
> }
> --
> 2.47.2
>
