linux-kernel - [PATCH v2] media: dvd_usb: memory leak in cinergyt2_fe

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Message-Id: <20210525130652.1498800-1-mudongliangabcd@gmail.com>
Date:   Tue, 25 May 2021 21:06:52 +0800
From:   Dongliang Mu <mudongliangabcd@...il.com>
To:     mchehab@...nel.org
Cc:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        Dongliang Mu <mudongliangabcd@...il.com>,
        syzbot+e1de8986786b3722050e@...kaller.appspotmail.com
Subject: [PATCH v2] media: dvd_usb: memory leak in cinergyt2_fe_attach

When the driver fails to talk with the hardware with dvb_usb_generic_rw,
it will return an error to dvb_usb_adapter_frontend_init. However, the
driver forgets to free the resource (e.g., struct cinergyt2_fe_state),
which leads to a memory leak.

Fix this by freeing struct cinergyt2_fe_state when dvb_usb_generic_rw
fails in cinergyt2_frontend_attach.

backtrace:
  [<0000000056e17b1a>] kmalloc include/linux/slab.h:552 [inline]
  [<0000000056e17b1a>] kzalloc include/linux/slab.h:682 [inline]
  [<0000000056e17b1a>] cinergyt2_fe_attach+0x21/0x80 drivers/media/usb/dvb-usb/cinergyT2-fe.c:271
  [<00000000ae0b1711>] cinergyt2_frontend_attach+0x21/0x70 drivers/media/usb/dvb-usb/cinergyT2-core.c:74
  [<00000000d0254861>] dvb_usb_adapter_frontend_init+0x11b/0x1b0 drivers/media/usb/dvb-usb/dvb-usb-dvb.c:290
  [<0000000002e08ac6>] dvb_usb_adapter_init drivers/media/usb/dvb-usb/dvb-usb-init.c:84 [inline]
  [<0000000002e08ac6>] dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:173 [inline]
  [<0000000002e08ac6>] dvb_usb_device_init.cold+0x4d0/0x6ae drivers/media/usb/dvb-usb/dvb-usb-init.c:287

Reported-by: syzbot+e1de8986786b3722050e@...kaller.appspotmail.com
Signed-off-by: Dongliang Mu <mudongliangabcd@...il.com>
---
v1->v2: move fix to cinergyt2_frontend_attach other than dvb-usb core
 drivers/media/usb/dvb-usb/cinergyT2-core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/media/usb/dvb-usb/cinergyT2-core.c b/drivers/media/usb/dvb-usb/cinergyT2-core.c
index 969a7ec71dff..4116ba5c45fc 100644
--- a/drivers/media/usb/dvb-usb/cinergyT2-core.c
+++ b/drivers/media/usb/dvb-usb/cinergyT2-core.c
@@ -78,6 +78,8 @@ static int cinergyt2_frontend_attach(struct dvb_usb_adapter *adap)
 
 	ret = dvb_usb_generic_rw(d, st->data, 1, st->data, 3, 0);
 	if (ret < 0) {
+		if (adap->fe_adap[0].fe)
+			adap->fe_adap[0].fe->ops.release(adap->fe_adap[0].fe);
 		deb_rc("cinergyt2_power_ctrl() Failed to retrieve sleep state info\n");
 	}
 	mutex_unlock(&d->data_mutex);
-- 
2.25.1