From: Dan Carpenter dan.carpenter@oracle.com

[ Upstream commit 329101244f214952606359d254ae883b7109e1a5 ]

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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/staging/greybus/light.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/greybus/light.c b/drivers/staging/greybus/light.c index 9f01427f35f9..1cb82cc28aa7 100644 --- a/drivers/staging/greybus/light.c +++ b/drivers/staging/greybus/light.c @@ -1102,21 +1102,21 @@ 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)