CVE-2022-50626

About vulnerability

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: [] dvb_usb_adapter_init drivers/media/usb/dvb-usb/dvb-usb-init.c:75 [inline] [] dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:184 [inline] [] dvb_usb_device_init.cold+0x4e5/0x79e drivers/media/usb/dvb-usb/dvb-usb-init.c:308 [] dib0700_probe+0x8d/0x1b0 drivers/media/usb/dvb-usb/dib0700_core.c:883 [] usb_probe_interface+0x177/0x370 drivers/usb/core/driver.c:396 [] call_driver_probe drivers/base/dd.c:542 [inline] [] really_probe.part.0+0xe7/0x310 drivers/base/dd.c:621 [] really_probe drivers/base/dd.c:583 [inline] [] __driver_probe_device+0x10c/0x1e0 drivers/base/dd.c:752 [] driver_probe_device+0x2a/0x120 drivers/base/dd.c:782 [] __device_attach_driver+0xf6/0x140 drivers/base/dd.c:899 [] bus_for_each_drv+0xb7/0x100 drivers/base/bus.c:427 [] __device_attach+0x122/0x260 drivers/base/dd.c:970 [] bus_probe_device+0xc6/0xe0 drivers/base/bus.c:487 [] device_add+0x5fb/0xdf0 drivers/base/core.c:3405 [] usb_set_configuration+0x8f2/0xb80 drivers/usb/core/message.c:2170 [] usb_generic_driver_probe+0x8c/0xc0 drivers/usb/core/generic.c:238 [] usb_probe_device+0x5c/0x140 drivers/usb/core/driver.c:293 [] call_driver_probe drivers/base/dd.c:542 [inline] [] really_probe.part.0+0xe7/0x310 drivers/base/dd.c:621 [] really_probe drivers/base/dd.c:583 [inline] [] __driver_probe_device+0x10c/0x1e0 drivers/base/dd.c:752

Affected product:

AlmaLinux 9.2 ESU , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , TuxCare 9.6 ESU

Affected packages:

kernel @ 4.18.0 (+4 more)

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: [] dvb_usb_adapter_init drivers/media/usb/dvb-usb/dvb-usb-init.c:75 [inline] [] dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:184 [inline] [] dvb_usb_device_init.cold+0x4e5/0x79e drivers/media/usb/dvb-usb/dvb-usb-init.c:308 [] dib0700_probe+0x8d/0x1b0 drivers/media/usb/dvb-usb/dib0700_core.c:883 [] usb_probe_interface+0x177/0x370 drivers/usb/core/driver.c:396 [] call_driver_probe drivers/base/dd.c:542 [inline] [] really_probe.part.0+0xe7/0x310 drivers/base/dd.c:621 [] really_probe drivers/base/dd.c:583 [inline] [] __driver_probe_device+0x10c/0x1e0 drivers/base/dd.c:752 [] driver_probe_device+0x2a/0x120 drivers/base/dd.c:782 [] __device_attach_driver+0xf6/0x140 drivers/base/dd.c:899 [] bus_for_each_drv+0xb7/0x100 drivers/base/bus.c:427 [] __device_attach+0x122/0x260 drivers/base/dd.c:970 [] bus_probe_device+0xc6/0xe0 drivers/base/bus.c:487 [] device_add+0x5fb/0xdf0 drivers/base/core.c:3405 [] usb_set_configuration+0x8f2/0xb80 drivers/usb/core/message.c:2170 [] usb_generic_driver_probe+0x8c/0xc0 drivers/usb/core/generic.c:238 [] usb_probe_device+0x5c/0x140 drivers/usb/core/driver.c:293 [] call_driver_probe drivers/base/dd.c:542 [inline] [] really_probe.part.0+0xe7/0x310 drivers/base/dd.c:621 [] really_probe drivers/base/dd.c:583 [inline] [] __driver_probe_device+0x10c/0x1e0 drivers/base/dd.c:752