media: dvb-usb: fix memory leak in cinergyt2_frontend_attach

PATCH In review Pavel Skripkin 2 participants 2 messages Jun 20, 2021 – Aug 11, 2021 Media (V4L/DVB)

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Pavel Skripkin

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2021-06-20 20:23 UTC #0 lore raw

PATCH 1/1 media: dvb-usb: fix memory leak in cinergyt2_frontend_attach

My local syzbot instance hit a memory leak in
cinergyt2_frontend_attach() [1].

The problem was in non-freed dvb_frontend in case of error. If dvb_usb_generic_rw() call fails, an error will be returned from cinergyt2_frontend_attach() [1] and num_adapters_initialized of dvb_usb_device won't be incremented. That means dvb usb library won't take care of freeing allocated frontend.

Fail log:

BUG: memory leak
unreferenced object 0xffff88801d9c6000 (size 2048):
  comm "kworker/1:3", pid 2960, jiffies 4295150569 (age 17.150s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 54 65 72 72 61 54 65 63  ........TerraTec
    2f 71 61 6e 75 20 55 53 42 32 2e 30 20 48 69 67  /qanu USB2.0 Hig
  backtrace:
    [<ffffffff85e169f0>] kmalloc include/linux/slab.h:556 [inline]
    [<ffffffff85e169f0>] kzalloc include/linux/slab.h:686 [inline]
    [<ffffffff85e169f0>] cinergyt2_fe_attach+0x40/0x110 drivers/media/usb/dvb-usb/cinergyT2-fe.c:271
    [<ffffffff85e15b31>] cinergyt2_frontend_attach+0x61/0x140 drivers/media/usb/dvb-usb/cinergyT2-core.c:74 [1]
    [<ffffffff85dcd71e>] dvb_usb_adapter_frontend_init+0x35e/0x5b0 drivers/media/usb/dvb-usb/dvb-usb-dvb.c:290
    [<ffffffff88f98e83>] dvb_usb_adapter_init drivers/media/usb/dvb-usb/dvb-usb-init.c:90 [inline]
    [<ffffffff88f98e83>] dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:184 [inline]

Fixes 986bd1e58b18 ("V4L/DVB (9107): Alternative version of Terratec Cinergy T2

driver")

Signed-off-by Pavel Skripkin <[email protected]>

---
 drivers/media/usb/dvb-usb/cinergyT2-core.c | 1 +
 1 file changed, 1 insertion(+)

drivers/media/usb/dvb-usb/cinergyT2-core.c +1 -0

index 969a7ec71dff..fb60af097535 100644
@@ -79,6 +79,7 @@ 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) {
 		deb_rc("cinergyt2_power_ctrl() Failed to retrieve sleep state info\n");
+		kfree(adap->fe_adap[0].fe);
 	}
 	mutex_unlock(&d->data_mutex);

Signature · 1 line

2.32.0

Sean Young

2021-08-11 21:54 UTC #1 lore raw

Quoted 8 lines · Pavel Skripkin

My local syzbot instance hit a memory leak in
cinergyt2_frontend_attach() [1].
The problem was in non-freed dvb_frontend in case of error. If dvb_usb_generic_rw() call fails, an error will be returned from cinergyt2_frontend_attach() [1] and num_adapters_initialized of dvb_usb_device won't be incremented. That means dvb usb library won't take care of freeing allocated frontend.

This issue is already fixed by:

9ad1efee086e0 media: dvd_usb: memory leak in cinergyt2_fe_attach

Thanks for reporting and making a patch though.

Sean

Quoted 38 lines