[PATCH 4.19 018/243] Input: cyttsp4_core - fix use after free bug

Greg Kroah-Hartman
2019-12-11T15:55:22Z

From: Pan Bian <bianpan2016@163.com>

[ Upstream commit 79aae6acbef16f720a7949f8fc6ac69816c79d62 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 727c3232517cd..c84ee739a8d50 100644
--- a/drivers/input/touchscreen/cyttsp4_core.c
+++ b/drivers/input/touchscreen/cyttsp4_core.c
@@ -2000,11 +2000,6 @@ 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)
@@ -2014,8 +2009,6 @@ 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;
--
2.20.1