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

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Date:   Tue, 25 May 2021 13:33:59 +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] media: dvd_usb: memory leak in cinergyt2_fe_attach

When cinergyt2_frontend_attach returns a negative value, the allocation
is already successful, but in the error handling, there is no any clean
corresponding operation, which leads to memory leak.

Fix it by freeing struct cinergyt2_fe_state when the return value is
nonzero.

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>
---
 drivers/media/usb/dvb-usb/dvb-usb-dvb.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/dvb-usb/dvb-usb-dvb.c b/drivers/media/usb/dvb-usb/dvb-usb-dvb.c
index 0a7f8ba90992..f9f004fb0a92 100644
--- a/drivers/media/usb/dvb-usb/dvb-usb-dvb.c
+++ b/drivers/media/usb/dvb-usb/dvb-usb-dvb.c
@@ -288,7 +288,7 @@ int dvb_usb_adapter_frontend_init(struct dvb_usb_adapter *adap)
 		}
 
 		ret = adap->props.fe[i].frontend_attach(adap);
-		if (ret || adap->fe_adap[i].fe == NULL) {
+		if (adap->fe_adap[i].fe == NULL) {
 			/* only print error when there is no FE at all */
 			if (i == 0)
 				err("no frontend was attached by '%s'",
@@ -297,6 +297,12 @@ int dvb_usb_adapter_frontend_init(struct dvb_usb_adapter *adap)
 			return 0;
 		}
 
+		if (ret) {
+			struct dvb_frontend *fe = adap->fe_adap[i].fe;
+
+			fe->ops.release(fe);
+			return 0;
+		}
+
 		adap->fe_adap[i].fe->id = i;
 
 		/* re-assign sleep and wakeup functions */
-- 
2.25.1