CVE-2021-47583
In the Linux kernel, the following vulnerability has been resolved: media: mxl111sf: change mutex_init() location Syzbot reported, that mxl111sf_ctrl_msg() uses uninitialized mutex. The problem was in wrong mutex_init() location. Previous mutex_init(&state->msg_lock) call was in ->init() function, but dvb_usbv2_init() has this order of calls: dvb_usbv2_init() dvb_usbv2_adapter_init() dvb_usbv2_adapter_frontend_init() props->frontend_attach() props->init() Since mxl111sf_* devices call mxl111sf_ctrl_msg() in ->frontend_attach() internally we need to initialize state->msg_lock before frontend_attach(). To achieve it, ->probe() call added to all mxl111sf_* devices, which will simply initiaize mutex.
02 / AFFECTED SOFTWARE
Affected packages
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: media: mxl111sf: change mutex_init() location Syzbot reported, that mxl111sf_ctrl_msg() uses uninitialized mutex. The problem was in wrong mutex_init() location. Previous mutex_init(&state->msg_lock) call was in ->init() function, but dvb_usbv2_init() has this order of calls: dvb_usbv2_init() dvb_usbv2_adapter_init() dvb_usbv2_adapter_frontend_init() props->frontend_attach() props->init() Since mxl111sf_* devices call mxl111sf_ctrl_msg() in ->frontend_attach() internally we need to initialize state->msg_lock before frontend_attach(). To achieve it, ->probe() call added to all mxl111sf_* devices, which will simply initiaize mutex.
05 / REFERENCES
Further evidence
- https://git.kernel.org/stable/c/44870a9e7a3c24acbb3f888b2a7cc22c9bdf7e7f
- https://git.kernel.org/stable/c/4b2d9600b31f9ba7adbc9f3c54a068615d27b390
- https://git.kernel.org/stable/c/8c6fdf62bfe1bc72bfceeaf832ef7499c7ed09ba
- https://git.kernel.org/stable/c/96f182c9f48b984447741f054ec301fdc8517035
- https://git.kernel.org/stable/c/b99bdf127af91d53919e96292c05f737c45ea59a