From 79aae6acbef16f720a7949f8fc6ac69816c79d62 Mon Sep 17 00:00:00 2001

From: Pan Bian <bianpan2016@163.com>

Date: Tue, 12 Nov 2019 17:04:54 -0800

Subject: [PATCH] Input: cyttsp4_core - fix use after free bug

Git-commit: 79aae6acbef16f720a7949f8fc6ac69816c79d62

Patch-mainline: v5.4-rc8

References: bsc#1051510

The device md->input is used after it is released. Setting the device

data to NULL is unnecessary as the device is never used again. Instead,

md->input should be assigned NULL to avoid accessing the freed memory

accidently. Besides, checking md->si against NULL is superfluous as it

points to a variable address, which cannot be NULL.

Signed-off-by: Pan Bian <bianpan2016@163.com>

Link: https://lore.kernel.org/r/1572936379-6423-1-git-send-email-bianpan2016@163.com

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/input/touchscreen/cyttsp4_core.c | 7 -------

 1 file changed, 7 deletions(-)

diff --git a/drivers/input/touchscreen/cyttsp4_core.c b/drivers/input/touchscreen/cyttsp4_core.c

index 4b22d49a0f49..6bcffc930384 100644

--- a/drivers/input/touchscreen/cyttsp4_core.c

+++ b/drivers/input/touchscreen/cyttsp4_core.c

@@ -1990,11 +1990,6 @@ static int cyttsp4_mt_probe(struct cyttsp4 *cd)

 	/* get sysinfo */

 	md->si = &cd->sysinfo;

-	if (!md->si) {

-		dev_err(dev, "%s: Fail get sysinfo pointer from core p=%p\n",

-			__func__, md->si);

-		goto error_get_sysinfo;

-	}

 	rc = cyttsp4_setup_input_device(cd);

 	if (rc)

@@ -2004,8 +1999,6 @@ static int cyttsp4_mt_probe(struct cyttsp4 *cd)

 error_init_input:

 	input_free_device(md->input);

-error_get_sysinfo:

-	input_set_drvdata(md->input, NULL);

 error_alloc_failed:

 	dev_err(dev, "%s failed.\n", __func__);

 	return rc;

-- 

2.16.4