In parport_attach, the return value of ida_alloc is unchecked, witch leads
to the use of an invalid index value.

To address this issue, index should be checked. When the index value is
abnormal, the device should be freed.

Found by code review, compile tested only.

Cc: stable@vger.kernel.org
Fixes: fb56d97df70e ("pps: client: use new parport device model")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
---
Changes in v3:
- modified Fixes tag as suggestions.
Changes in v2:
- removed error output as suggestions.
---
 drivers/pps/clients/pps_parport.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/pps/clients/pps_parport.c b/drivers/pps/clients/pps_parport.c
index 63d03a0df5cc..abaffb4e1c1c 100644
--- a/drivers/pps/clients/pps_parport.c
+++ b/drivers/pps/clients/pps_parport.c
@@ -149,6 +149,9 @@ static void parport_attach(struct parport *port)
 	}
 
 	index = ida_alloc(&pps_client_index, GFP_KERNEL);
+	if (index < 0)
+		goto err_free_device;
+
 	memset(&pps_client_cb, 0, sizeof(pps_client_cb));
 	pps_client_cb.private = device;
 	pps_client_cb.irq_func = parport_irq;
@@ -159,7 +162,7 @@ static void parport_attach(struct parport *port)
 						    index);
 	if (!device->pardev) {
 		pr_err("couldn't register with %s\n", port->name);
-		goto err_free;
+		goto err_free_ida;
 	}
 
 	if (parport_claim_or_block(device->pardev) < 0) {
@@ -187,8 +190,9 @@ static void parport_attach(struct parport *port)
 	parport_release(device->pardev);
 err_unregister_dev:
 	parport_unregister_device(device->pardev);
-err_free:
+err_free_ida:
 	ida_free(&pps_client_index, index);
+err_free_device:
 	kfree(device);
 }
 
-- 
2.25.1

On 28/08/24 15:18, Ma Ke wrote:
> In parport_attach, the return value of ida_alloc is unchecked, witch leads
> to the use of an invalid index value.
> 
> To address this issue, index should be checked. When the index value is
> abnormal, the device should be freed.
> 
> Found by code review, compile tested only.
> 
> Cc: stable@vger.kernel.org
> Fixes: fb56d97df70e ("pps: client: use new parport device model")
> Signed-off-by: Ma Ke <make24@iscas.ac.cn>

Acked-by: Rodolfo Giometti <giometti@enneenne.com>

> ---
> Changes in v3:
> - modified Fixes tag as suggestions.
> Changes in v2:
> - removed error output as suggestions.
> ---
>   drivers/pps/clients/pps_parport.c | 8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pps/clients/pps_parport.c b/drivers/pps/clients/pps_parport.c
> index 63d03a0df5cc..abaffb4e1c1c 100644
> --- a/drivers/pps/clients/pps_parport.c
> +++ b/drivers/pps/clients/pps_parport.c
> @@ -149,6 +149,9 @@ static void parport_attach(struct parport *port)
>   	}
>   
>   	index = ida_alloc(&pps_client_index, GFP_KERNEL);
> +	if (index < 0)
> +		goto err_free_device;
> +
>   	memset(&pps_client_cb, 0, sizeof(pps_client_cb));
>   	pps_client_cb.private = device;
>   	pps_client_cb.irq_func = parport_irq;
> @@ -159,7 +162,7 @@ static void parport_attach(struct parport *port)
>   						    index);
>   	if (!device->pardev) {
>   		pr_err("couldn't register with %s\n", port->name);
> -		goto err_free;
> +		goto err_free_ida;
>   	}
>   
>   	if (parport_claim_or_block(device->pardev) < 0) {
> @@ -187,8 +190,9 @@ static void parport_attach(struct parport *port)
>   	parport_release(device->pardev);
>   err_unregister_dev:
>   	parport_unregister_device(device->pardev);
> -err_free:
> +err_free_ida:
>   	ida_free(&pps_client_index, index);
> +err_free_device:
>   	kfree(device);
>   }
>   

-- 
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Linux Device Driver                          giometti@linux.it
Embedded Systems                     phone:  +39 349 2432127
UNIX programming