Patch "greybus: lights: check return of get_channel_from_mode" has been added to the 4.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    greybus: lights: check return of get_channel_from_mode

to the 4.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     greybus-lights-check-return-of-get_channel_from_mode.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 05da1e9d8ff37cf72a26de8a3537dd2e091b6a70
Author: Rui Miguel Silva <rmfrfs@xxxxxxxxx>
Date:   Mon Mar 25 22:09:55 2024 +0000

    greybus: lights: check return of get_channel_from_mode
    
    [ Upstream commit a1ba19a1ae7cd1e324685ded4ab563e78fe68648 ]
    
    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@xxxxxxxxxxxx
    
    Fixes: 2870b52bae4c ("greybus: lights: add lights implementation")
    Reported-by: Mikhail Lobanov <m.lobanov@xxxxxxxxxxxx>
    Suggested-by: Mikhail Lobanov <m.lobanov@xxxxxxxxxxxx>
    Suggested-by: Alex Elder <elder@xxxxxxxx>
    Signed-off-by: Rui Miguel Silva <rmfrfs@xxxxxxxxx>
    Link: https://lore.kernel.org/r/20240325221549.2185265-1-rmfrfs@xxxxxxxxx
    Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/staging/greybus/light.c b/drivers/staging/greybus/light.c
index 8c5819d1e1abe..9dc51315f1fc6 100644
--- a/drivers/staging/greybus/light.c
+++ b/drivers/staging/greybus/light.c
@@ -149,6 +149,9 @@ 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);
@@ -552,7 +555,10 @@ 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;