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staging: greybus: light: fix a couple double frees

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The problem is in gb_lights_request_handler().  If we get a request to
change the config then we release the light with gb_lights_light_release()
and re-allocated it.  However, if the allocation fails part way through
then we call gb_lights_light_release() again.  This can lead to a couple
different double frees where we haven't cleared out the original values:

	gb_lights_light_v4l2_unregister(light);
	...
	kfree(light->channels);
	kfree(light->name);

I also made a small change to how we set "light->channels_count = 0;".
The original code handled this part fine and did not cause a use after
free but it was sort of complicated to read.

Fixes: 2870b52bae4c ("greybus: lights: add lights implementation")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
Link: https://lore.kernel.org/r/20190829122839.GA20116@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Dan Carpenter 2019-08-29 15:28:39 +03:00 committed by Greg Kroah-Hartman
parent 2073805721
commit 329101244f
1 changed files with 6 additions and 6 deletions
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12
drivers/staging/greybus/light.c
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@ -1096,21 +1096,21 @@ static void gb_lights_channel_release(struct gb_channel *channel)
static void gb_lights_light_release(struct gb_light *light)
{
int i;
int count;
light->ready = false;
count = light->channels_count;
if (light->has_flash)
gb_lights_light_v4l2_unregister(light);
light->has_flash = false;
for (i = 0; i < count; i++) {
for (i = 0; i < light->channels_count; i++)
gb_lights_channel_release(&light->channels[i]);
light->channels_count--;
}
light->channels_count = 0;
kfree(light->channels);
light->channels = NULL;
kfree(light->name);
light->name = NULL;
}
static void gb_lights_release(struct gb_lights *glights)