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media: edia: dvbdev: fix a use-after-free
[ Upstream commit8c64f4cdf4
] In dvb_register_device, *pdvbdev is set equal to dvbdev, which is freed in several error-handling paths. However, *pdvbdev is not set to NULL after dvbdev's deallocation, causing use-after-frees in many places, for example, in the following call chain: budget_register |-> dvb_dmxdev_init |-> dvb_register_device |-> dvb_dmxdev_release |-> dvb_unregister_device |-> dvb_remove_device |-> dvb_device_put |-> kref_put When calling dvb_unregister_device, dmxdev->dvbdev (i.e. *pdvbdev in dvb_register_device) could point to memory that had been freed in dvb_register_device. Thereafter, this pointer is transferred to kref_put and triggering a use-after-free. Link: https://lore.kernel.org/linux-media/20240203134046.3120099-1-alexious@zju.edu.cn Fixes:b619010247
("V4L/DVB (5244): Dvbdev: fix illegal re-usage of fileoperations struct") Signed-off-by: Zhipeng Lu <alexious@zju.edu.cn> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
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parent
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commit
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1 changed files with 5 additions and 0 deletions
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@ -490,6 +490,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev,
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dvbdevfops = kmemdup(template->fops, sizeof(*dvbdevfops), GFP_KERNEL);
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if (!dvbdevfops) {
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kfree(dvbdev);
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*pdvbdev = NULL;
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mutex_unlock(&dvbdev_register_lock);
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return -ENOMEM;
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}
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@ -498,6 +499,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev,
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if (!new_node) {
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kfree(dvbdevfops);
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kfree(dvbdev);
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*pdvbdev = NULL;
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mutex_unlock(&dvbdev_register_lock);
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return -ENOMEM;
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}
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@ -531,6 +533,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev,
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}
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list_del(&dvbdev->list_head);
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kfree(dvbdev);
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*pdvbdev = NULL;
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up_write(&minor_rwsem);
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mutex_unlock(&dvbdev_register_lock);
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return -EINVAL;
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@ -553,6 +556,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev,
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dvb_media_device_free(dvbdev);
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list_del(&dvbdev->list_head);
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kfree(dvbdev);
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*pdvbdev = NULL;
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mutex_unlock(&dvbdev_register_lock);
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return ret;
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}
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@ -571,6 +575,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev,
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dvb_media_device_free(dvbdev);
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list_del(&dvbdev->list_head);
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kfree(dvbdev);
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*pdvbdev = NULL;
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mutex_unlock(&dvbdev_register_lock);
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return PTR_ERR(clsdev);
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}
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