From 8dbdcc7269a83305ee9d677b75064d3530a48ee2 Mon Sep 17 00:00:00 2001

From: Zhou Qingyang <zhou1615@umn.edu>

Date: Tue, 30 Nov 2021 16:38:05 +0100

Subject: [PATCH] media: dib8000: Fix a memleak in dib8000_init()

Git-commit: 8dbdcc7269a83305ee9d677b75064d3530a48ee2

References: git-fixes

Patch-mainline: v5.17-rc1

In dib8000_init(), the variable fe is not freed or passed out on the

failure of dib8000_identify(&state->i2c), which could lead to a memleak.

Fix this bug by adding a kfree of fe in the error path.

This bug was found by a static analyzer. The analysis employs

differential checking to identify inconsistent security operations

(e.g., checks or kfrees) between two code paths and confirms that the

inconsistent operations are not recovered in the current function or

the callers, so they constitute bugs.

Note that, as a bug found by static analysis, it can be a false

positive or hard to trigger. Multiple researchers have cross-reviewed

the bug.

Builds with CONFIG_DVB_DIB8000=m show no new warnings,

and our static analyzer no longer warns about this code.

Fixes: 77e2c0f5d471 ("V4L/DVB (12900): DiB8000: added support for DiBcom ISDB-T/ISDB-Tsb demodulator DiB8000")

Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Signed-off-by: Oliver Neukum <oneukum@suse.com>

---

 drivers/media/dvb-frontends/dib8000.c | 4 +++-

 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/media/dvb-frontends/dib8000.c b/drivers/media/dvb-frontends/dib8000.c

index bb02354a48b8..d67f2dd997d0 100644

--- a/drivers/media/dvb-frontends/dib8000.c

+++ b/drivers/media/dvb-frontends/dib8000.c

@@ -4473,8 +4473,10 @@ static struct dvb_frontend *dib8000_init(struct i2c_adapter *i2c_adap, u8 i2c_ad

 	state->timf_default = cfg->pll->timf;

-	if (dib8000_identify(&state->i2c) == 0)

+	if (dib8000_identify(&state->i2c) == 0) {

+		kfree(fe);

 		goto error;

+	}

 	dibx000_init_i2c_master(&state->i2c_master, DIB8000, state->i2c.adap, state->i2c.addr);

-- 

2.35.3