Re: [PATCH][next] platform/chrome: wilco_ec: fix null pointer dereference on failed kzalloc
On Tue, Jun 18, 2019 at 11:30 PM Dan Carpenter wrote:
>
> On Tue, Jun 18, 2019 at 04:39:24PM +0100, Colin King wrote:
> > diff --git a/drivers/platform/chrome/wilco_ec/event.c
> > b/drivers/platform/chrome/wilco_ec/event.c
> > index c975b76e6255..e251a989b152 100644
> > --- a/drivers/platform/chrome/wilco_ec/event.c
> > +++ b/drivers/platform/chrome/wilco_ec/event.c
> > @@ -112,8 +112,11 @@ module_param(queue_size, int, 0644);
> > static struct ec_event_queue *event_queue_new(int capacity)
> > {
> > size_t entries_size = sizeof(struct ec_event *) * capacity;
> > - struct ec_event_queue *q = kzalloc(sizeof(*q) + entries_size,
> > -GFP_KERNEL);
> > + struct ec_event_queue *q;
> > +
> > + q = kzalloc(sizeof(*q) + entries_size, GFP_KERNEL);
> > + if (!q)
> > + return NULL;
>
> We have a new struct_size() macro designed for these allocations.
>
> q = kzalloc(struct_size(q, entries, capacity), GFP_KERNEL);
>
> The advantage is that it checks for integer overflows.
>
> regards,
> dan carpenter
>
Thanks Dan, I like that.
Dmitry Torokhov also had some thoughts on this patch at
https://crrev.com/c/1661053, I'll send a patch that adds this and
fixes his concerns in a bit.
Cheers,
Nick
Re: [PATCH][next] platform/chrome: wilco_ec: fix null pointer dereference on failed kzalloc
On Tue, Jun 18, 2019 at 04:39:24PM +0100, Colin King wrote:
> diff --git a/drivers/platform/chrome/wilco_ec/event.c
> b/drivers/platform/chrome/wilco_ec/event.c
> index c975b76e6255..e251a989b152 100644
> --- a/drivers/platform/chrome/wilco_ec/event.c
> +++ b/drivers/platform/chrome/wilco_ec/event.c
> @@ -112,8 +112,11 @@ module_param(queue_size, int, 0644);
> static struct ec_event_queue *event_queue_new(int capacity)
> {
> size_t entries_size = sizeof(struct ec_event *) * capacity;
> - struct ec_event_queue *q = kzalloc(sizeof(*q) + entries_size,
> -GFP_KERNEL);
> + struct ec_event_queue *q;
> +
> + q = kzalloc(sizeof(*q) + entries_size, GFP_KERNEL);
> + if (!q)
> + return NULL;
We have a new struct_size() macro designed for these allocations.
q = kzalloc(struct_size(q, entries, capacity), GFP_KERNEL);
The advantage is that it checks for integer overflows.
regards,
dan carpenter
Re: [PATCH][next] platform/chrome: wilco_ec: fix null pointer dereference on failed kzalloc
Hi Colin,
On Tue, Jun 18, 2019 at 04:39:24PM +0100, Colin King wrote:
> From: Colin Ian King
>
> If the kzalloc of the entries queue q fails a null pointer dereference
> occurs when accessing q->capacity and q->lock. Add a kzalloc failure
> check and handle the null return case in the calling function
> event_device_add.
>
> Addresses-Coverity: ("Dereference null return")
> Fixes: 75589e37d1dc ("platform/chrome: wilco_ec: Add circular buffer as event
> queue")
> Signed-off-by: Colin Ian King
Applied. Thanks.
Benson
> ---
> drivers/platform/chrome/wilco_ec/event.c | 12 ++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/platform/chrome/wilco_ec/event.c
> b/drivers/platform/chrome/wilco_ec/event.c
> index c975b76e6255..e251a989b152 100644
> --- a/drivers/platform/chrome/wilco_ec/event.c
> +++ b/drivers/platform/chrome/wilco_ec/event.c
> @@ -112,8 +112,11 @@ module_param(queue_size, int, 0644);
> static struct ec_event_queue *event_queue_new(int capacity)
> {
> size_t entries_size = sizeof(struct ec_event *) * capacity;
> - struct ec_event_queue *q = kzalloc(sizeof(*q) + entries_size,
> -GFP_KERNEL);
> + struct ec_event_queue *q;
> +
> + q = kzalloc(sizeof(*q) + entries_size, GFP_KERNEL);
> + if (!q)
> + return NULL;
>
> q->capacity = capacity;
> spin_lock_init(>lock);
> @@ -474,6 +477,11 @@ static int event_device_add(struct acpi_device *adev)
> /* Initialize the device data. */
> adev->driver_data = dev_data;
> dev_data->events = event_queue_new(queue_size);
> + if (!dev_data->events) {
> + kfree(dev_data);
> + error = -ENOMEM;
> + goto free_minor;
> + }
> init_waitqueue_head(_data->wq);
> dev_data->exist = true;
> atomic_set(_data->available, 1);
> --
> 2.20.1
>
--
Benson Leung
Staff Software Engineer
Chrome OS Kernel
Google Inc.
ble...@google.com
Chromium OS Project
ble...@chromium.org
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Re: [PATCH][next] platform/chrome: wilco_ec: fix null pointer dereference on failed kzalloc
Hi Nick, On Tue, Jun 18, 2019 at 11:15:03AM -0600, Nick Crews wrote: > Thanks Colin, good catch. > > Enric, could you squash this into the real commit? I've applied this to for-next and for-kernelci in chrome-platform. Thanks, Benson -- Benson Leung Staff Software Engineer Chrome OS Kernel Google Inc. ble...@google.com Chromium OS Project ble...@chromium.org signature.asc Description: PGP signature
Re: [PATCH][next] platform/chrome: wilco_ec: fix null pointer dereference on failed kzalloc
Thanks Colin, good catch.
Enric, could you squash this into the real commit?
On Tue, Jun 18, 2019 at 9:39 AM Colin King wrote:
>
> From: Colin Ian King
>
> If the kzalloc of the entries queue q fails a null pointer dereference
> occurs when accessing q->capacity and q->lock. Add a kzalloc failure
> check and handle the null return case in the calling function
> event_device_add.
>
> Addresses-Coverity: ("Dereference null return")
> Fixes: 75589e37d1dc ("platform/chrome: wilco_ec: Add circular buffer as event
> queue")
> Signed-off-by: Colin Ian King
> ---
> drivers/platform/chrome/wilco_ec/event.c | 12 ++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/platform/chrome/wilco_ec/event.c
> b/drivers/platform/chrome/wilco_ec/event.c
> index c975b76e6255..e251a989b152 100644
> --- a/drivers/platform/chrome/wilco_ec/event.c
> +++ b/drivers/platform/chrome/wilco_ec/event.c
> @@ -112,8 +112,11 @@ module_param(queue_size, int, 0644);
> static struct ec_event_queue *event_queue_new(int capacity)
> {
> size_t entries_size = sizeof(struct ec_event *) * capacity;
> - struct ec_event_queue *q = kzalloc(sizeof(*q) + entries_size,
> - GFP_KERNEL);
> + struct ec_event_queue *q;
> +
> + q = kzalloc(sizeof(*q) + entries_size, GFP_KERNEL);
> + if (!q)
> + return NULL;
>
> q->capacity = capacity;
> spin_lock_init(>lock);
> @@ -474,6 +477,11 @@ static int event_device_add(struct acpi_device *adev)
> /* Initialize the device data. */
> adev->driver_data = dev_data;
> dev_data->events = event_queue_new(queue_size);
> + if (!dev_data->events) {
> + kfree(dev_data);
> + error = -ENOMEM;
> + goto free_minor;
> + }
> init_waitqueue_head(_data->wq);
> dev_data->exist = true;
> atomic_set(_data->available, 1);
Signed-off-by: Nick Crews
> --
> 2.20.1
>
