media: edia: dvbdev: fix a use-after-free

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: 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.

References

• https://git.kernel.org/stable/c/d0f5c28333822f9baa5280d813124920720fd856
• https://git.kernel.org/stable/c/f20c3270f3ed5aa6919a87e4de9bf6c05fb57086
• https://git.kernel.org/stable/c/096237039d00c839f3e3a5fe6d001bf0db45b644
• https://git.kernel.org/stable/c/0d3fe80b6d175c220b3e252efc6c6777e700e98e
• https://git.kernel.org/stable/c/437a111f79a2f5b2a5f21e27fdec6f40c8768712
• https://git.kernel.org/stable/c/779e8db7efb22316c8581d6c229636d2f5694a62
• https://git.kernel.org/stable/c/35674111a043b0482a9bc69da8850a83f465b07d
• https://git.kernel.org/stable/c/b7586e902128e4fb7bfbb661cb52e4215a65637b
• https://git.kernel.org/stable/c/8c64f4cdf4e6cc5682c52523713af8c39c94e6d5