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| author | Zhipeng Lu <alexious@zju.edu.cn> | 2024-02-03 14:40:43 +0100 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@kernel.org> | 2024-02-07 06:06:03 +0100 |
| commit | 8c64f4cdf4e6cc5682c52523713af8c39c94e6d5 (patch) | |
| tree | c067c77f834eaf4601af4ef0d1e19fe6073218ca | |
| parent | 9651d3d2d691960e64f4c906081d75ae07eb47df (diff) | |
| download | linux-8c64f4cdf4e6cc5682c52523713af8c39c94e6d5.tar.gz | |
media: edia: dvbdev: fix a use-after-free
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: b61901024776 ("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>
| -rw-r--r-- | drivers/media/dvb-core/dvbdev.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/media/dvb-core/dvbdev.c b/drivers/media/dvb-core/dvbdev.c index 49f0eb7d0b9d3b..733d0bc4b4cc3a 100644 --- a/drivers/media/dvb-core/dvbdev.c +++ b/drivers/media/dvb-core/dvbdev.c @@ -490,6 +490,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev, dvbdevfops = kmemdup(template->fops, sizeof(*dvbdevfops), GFP_KERNEL); if (!dvbdevfops) { kfree(dvbdev); + *pdvbdev = NULL; mutex_unlock(&dvbdev_register_lock); return -ENOMEM; } @@ -498,6 +499,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev, if (!new_node) { kfree(dvbdevfops); kfree(dvbdev); + *pdvbdev = NULL; mutex_unlock(&dvbdev_register_lock); return -ENOMEM; } @@ -531,6 +533,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev, } list_del(&dvbdev->list_head); kfree(dvbdev); + *pdvbdev = NULL; up_write(&minor_rwsem); mutex_unlock(&dvbdev_register_lock); return -EINVAL; @@ -553,6 +556,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev, dvb_media_device_free(dvbdev); list_del(&dvbdev->list_head); kfree(dvbdev); + *pdvbdev = NULL; mutex_unlock(&dvbdev_register_lock); return ret; } @@ -571,6 +575,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev, dvb_media_device_free(dvbdev); list_del(&dvbdev->list_head); kfree(dvbdev); + *pdvbdev = NULL; mutex_unlock(&dvbdev_register_lock); return PTR_ERR(clsdev); } |