CVE-2022-50626 — media: dvb-usb: fix memory leak in dvb_usb_adapter_init()

Affected: Linux

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

media: dvb-usb: fix memory leak in dvb_usb_adapter_init()

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_ada…

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CVE-2022-50626 — media: dvb-usb: fix memory leak in dvb_usb_adapter_init()