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media: dvb-core: Fix ignored return value in dvb_register_frontend()

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[ Upstream commit a574359e2e71ce16be212df3a082ed60a4bd2c5f ]

In dvb_register_frontend(), dvb_register_device() is possible to fail
but its return value is ignored.

It will cause use-after-free when module is removed, because in
dvb_unregister_frontend() it tries to unregister a not registered
device.

BUG: KASAN: use-after-free in dvb_remove_device+0x18b/0x1f0 [dvb_core]
Read of size 4 at addr ffff88800dff4824 by task rmmod/428
CPU: 3 PID: 428 Comm: rmmod
Call Trace:
 <TASK>
 ...
 dvb_remove_device+0x18b/0x1f0 [dvb_core]
 dvb_unregister_frontend+0x7b/0x130 [dvb_core]
 vidtv_bridge_remove+0x6e/0x160 [dvb_vidtv_bridge]
 ...

Fix this by catching return value of dvb_register_device().
However the fe->refcount can't be put to zero immediately, because
there are still modules calling dvb_frontend_detach() when
dvb_register_frontend() fails.

Link: https://lore.kernel.org/linux-media/20221108033005.169095-1-chenzhongjin@huawei.com
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Chen Zhongjin 2022-11-08 03:30:05 +00:00 committed by Greg Kroah-Hartman
parent 3359f8d533
commit 9103bf2187
1 changed files with 7 additions and 1 deletions
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8
drivers/media/dvb-core/dvb_frontend.c
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@ -2961,6 +2961,7 @@ int dvb_register_frontend(struct dvb_adapter *dvb,
.name = fe->ops.info.name,
#endif
};
int ret;
dev_dbg(dvb->device, "%s:\n", __func__);
@ -2994,8 +2995,13 @@ int dvb_register_frontend(struct dvb_adapter *dvb,
"DVB: registering adapter %i frontend %i (%s)...\n",
fe->dvb->num, fe->id, fe->ops.info.name);
dvb_register_device(fe->dvb, &fepriv->dvbdev, &dvbdev_template,
ret = dvb_register_device(fe->dvb, &fepriv->dvbdev, &dvbdev_template,
fe, DVB_DEVICE_FRONTEND, 0);
if (ret) {
dvb_frontend_put(fe);
mutex_unlock(&frontend_mutex);
return ret;
}
/*
* Initialize the cache to the proper values according with the