releases/4.19.34/leds-lp55xx-fix-null-deref-on-firmware-load-failure.patch

   1 From c15e9ef788a7ea1969067cefbff09ed1f31686c8 Mon Sep 17 00:00:00 2001
   2 From: Michal Kazior <michal@plume.com>
   3 Date: Mon, 11 Feb 2019 10:29:27 +0100
   4 Subject: leds: lp55xx: fix null deref on firmware load failure
   5
   6 [ Upstream commit 5ddb0869bfc1bca6cfc592c74c64a026f936638c ]
   7
   8 I've stumbled upon a kernel crash and the logs
   9 pointed me towards the lp5562 driver:
  10
  11 > <4>[306013.841294] lp5562 0-0030: Direct firmware load for lp5562 failed with error -2
  12 > <4>[306013.894990] lp5562 0-0030: Falling back to user helper
  13 > ...
  14 > <3>[306073.924886] lp5562 0-0030: firmware request failed
  15 > <1>[306073.939456] Unable to handle kernel NULL pointer dereference at virtual address 00000000
  16 > <4>[306074.251011] PC is at _raw_spin_lock+0x1c/0x58
  17 > <4>[306074.255539] LR is at release_firmware+0x6c/0x138
  18 > ...
  19
  20 After taking a look I noticed firmware_release()
  21 could be called with either NULL or a dangling
  22 pointer.
  23
  24 Fixes: 10c06d178df11 ("leds-lp55xx: support firmware interface")
  25 Signed-off-by: Michal Kazior <michal@plume.com>
  26 Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
  27 Signed-off-by: Sasha Levin <sashal@kernel.org>
  28 ---
  29  drivers/leds/leds-lp55xx-common.c | 4 ++--
  30  1 file changed, 2 insertions(+), 2 deletions(-)
  31
  32 diff --git a/drivers/leds/leds-lp55xx-common.c b/drivers/leds/leds-lp55xx-common.c
  33 index 3d79a6380761..723f2f17497a 100644
  34 --- a/drivers/leds/leds-lp55xx-common.c
  35 +++ b/drivers/leds/leds-lp55xx-common.c
  36 @@ -201,7 +201,7 @@ static void lp55xx_firmware_loaded(const struct firmware *fw, void *context)
  37
  38         if (!fw) {
  39                 dev_err(dev, "firmware request failed\n");
  40 -               goto out;
  41 +               return;
  42         }
  43
  44         /* handling firmware data is chip dependent */
  45 @@ -214,9 +214,9 @@ static void lp55xx_firmware_loaded(const struct firmware *fw, void *context)
  46
  47         mutex_unlock(&chip->lock);
  48
  49 -out:
  50         /* firmware should be released for other channel use */
  51         release_firmware(chip->fw);
  52 +       chip->fw = NULL;
  53  }
  54
  55  static int lp55xx_request_firmware(struct lp55xx_chip *chip)
  56 --
  57 2.19.1
  58