greybus: lights: check return of get_channel_from_mode

If channel for the given node is not found we return null from
get_channel_from_mode. Make sure we validate the return pointer
before using it in two of the missing places.

This was originally reported in [0]:
Found by Linux Verification Center (linuxtesting.org) with SVACE.

[0] https://lore.kernel.org/all/20240301190425.120605-1-m.lobanov@rosalinux.ru

Fixes: 2870b52bae4c ("greybus: lights: add lights implementation")
Reported-by: Mikhail Lobanov <m.lobanov@rosalinux.ru>
Suggested-by: Mikhail Lobanov <m.lobanov@rosalinux.ru>
Suggested-by: Alex Elder <elder@ieee.org>
Signed-off-by: Rui Miguel Silva <rmfrfs@gmail.com>
Link: https://lore.kernel.org/r/20240325221549.2185265-1-rmfrfs@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/greybus/light.c b/drivers/staging/greybus/light.c
index a5c2fe963866db66a487eaa824d53329ffc0c080..00360f4a04854aa9bfc85c8f40bfd0444ad82900 100644 (file)
--- a/drivers/staging/greybus/light.c
+++ b/drivers/staging/greybus/light.c
@@ -142,6 +142,9 @@ static int __gb_lights_flash_brightness_set(struct gb_channel *channel)
                channel = get_channel_from_mode(channel->light,
                                                GB_CHANNEL_MODE_TORCH);
 
+       if (!channel)
+               return -EINVAL;
+
        /* For not flash we need to convert brightness to intensity */
        intensity = channel->intensity_uA.min +
                        (channel->intensity_uA.step * channel->led->brightness);
@@ -528,7 +531,10 @@ static int gb_lights_light_v4l2_register(struct gb_light *light)
        }
 
        channel_flash = get_channel_from_mode(light, GB_CHANNEL_MODE_FLASH);
-       WARN_ON(!channel_flash);
+       if (!channel_flash) {
+               dev_err(dev, "failed to get flash channel from mode\n");
+               return -EINVAL;
+       }
 
        fled = &channel_flash->fled;