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Subject[PATCH AUTOSEL 5.15 36/46] media: dvb-usb: fix memory leak in dvb_usb_adapter_init()
Date
From: Mazin Al Haddad <mazinalhaddad05@gmail.com>

[ Upstream commit 94d90fb06b94a90c176270d38861bcba34ce377d ]

Syzbot reports a memory leak in "dvb_usb_adapter_init()".
The leak is due to not accounting for and freeing current iteration's
adapter->priv in case of an error. Currently if an error occurs,
it will exit before incrementing "num_adapters_initalized",
which is used as a reference counter to free all adap->priv
in "dvb_usb_adapter_exit()". There are multiple error paths that
can exit from before incrementing the counter. Including the
error handling paths for "dvb_usb_adapter_stream_init()",
"dvb_usb_adapter_dvb_init()" and "dvb_usb_adapter_frontend_init()"
within "dvb_usb_adapter_init()".

This means that in case of an error in any of these functions the
current iteration is not accounted for and the current iteration's
adap->priv is not freed.

Fix this by freeing the current iteration's adap->priv in the
"stream_init_err:" label in the error path. The rest of the
(accounted for) adap->priv objects are freed in dvb_usb_adapter_exit()
as expected using the num_adapters_initalized variable.

Syzbot report:

BUG: memory leak
unreferenced object 0xffff8881172f1a00 (size 512):
comm "kworker/0:2", pid 139, jiffies 4294994873 (age 10.960s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff844af012>] dvb_usb_adapter_init drivers/media/usb/dvb-usb/dvb-usb-init.c:75 [inline]
[<ffffffff844af012>] dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:184 [inline]
[<ffffffff844af012>] dvb_usb_device_init.cold+0x4e5/0x79e drivers/media/usb/dvb-usb/dvb-usb-init.c:308
[<ffffffff830db21d>] dib0700_probe+0x8d/0x1b0 drivers/media/usb/dvb-usb/dib0700_core.c:883
[<ffffffff82d3fdc7>] usb_probe_interface+0x177/0x370 drivers/usb/core/driver.c:396
[<ffffffff8274ab37>] call_driver_probe drivers/base/dd.c:542 [inline]
[<ffffffff8274ab37>] really_probe.part.0+0xe7/0x310 drivers/base/dd.c:621
[<ffffffff8274ae6c>] really_probe drivers/base/dd.c:583 [inline]
[<ffffffff8274ae6c>] __driver_probe_device+0x10c/0x1e0 drivers/base/dd.c:752
[<ffffffff8274af6a>] driver_probe_device+0x2a/0x120 drivers/base/dd.c:782
[<ffffffff8274b786>] __device_attach_driver+0xf6/0x140 drivers/base/dd.c:899
[<ffffffff82747c87>] bus_for_each_drv+0xb7/0x100 drivers/base/bus.c:427
[<ffffffff8274b352>] __device_attach+0x122/0x260 drivers/base/dd.c:970
[<ffffffff827498f6>] bus_probe_device+0xc6/0xe0 drivers/base/bus.c:487
[<ffffffff82745cdb>] device_add+0x5fb/0xdf0 drivers/base/core.c:3405
[<ffffffff82d3d202>] usb_set_configuration+0x8f2/0xb80 drivers/usb/core/message.c:2170
[<ffffffff82d4dbfc>] usb_generic_driver_probe+0x8c/0xc0 drivers/usb/core/generic.c:238
[<ffffffff82d3f49c>] usb_probe_device+0x5c/0x140 drivers/usb/core/driver.c:293
[<ffffffff8274ab37>] call_driver_probe drivers/base/dd.c:542 [inline]
[<ffffffff8274ab37>] really_probe.part.0+0xe7/0x310 drivers/base/dd.c:621
[<ffffffff8274ae6c>] really_probe drivers/base/dd.c:583 [inline]
[<ffffffff8274ae6c>] __driver_probe_device+0x10c/0x1e0 drivers/base/dd.c:752

Link: https://syzkaller.appspot.com/bug?extid=f66dd31987e6740657be
Reported-and-tested-by: syzbot+f66dd31987e6740657be@syzkaller.appspotmail.com

Link: https://lore.kernel.org/linux-media/20220824012152.539788-1-mazinalhaddad05@gmail.com
Signed-off-by: Mazin Al Haddad <mazinalhaddad05@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/usb/dvb-usb/dvb-usb-init.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c
index 61439c8f33ca..58eea8ab5477 100644
--- a/drivers/media/usb/dvb-usb/dvb-usb-init.c
+++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c
@@ -81,7 +81,7 @@ static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)

ret = dvb_usb_adapter_stream_init(adap);
if (ret)
- return ret;
+ goto stream_init_err;

ret = dvb_usb_adapter_dvb_init(adap, adapter_nrs);
if (ret)
@@ -114,6 +114,8 @@ static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
dvb_usb_adapter_dvb_exit(adap);
dvb_init_err:
dvb_usb_adapter_stream_exit(adap);
+stream_init_err:
+ kfree(adap->priv);
return ret;
}

--
2.35.1
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