In the Linux kernel, the following vulnerability has been resolved: media: xc2028: avoid use-after-free in load_firmware_cb() syzkaller reported use-after-free in load_firmware_cb() [1]. The reason is because the module allocated a struct tuner in tuner_probe(), and then the module initialization failed, the struct tuner was released. A worker which created during module initialization accesses this struct tuner later, it caused use-after-free. The process is as follows: task-6504 worker_thread tuner_probe <= alloc dvb_frontend [2] ... request_firmware_nowait <= create a worker ... tuner_remove <= free dvb_frontend ... request_firmware_work_func <= the firmware is ready load_firmware_cb <= but now the dvb_frontend has been freed To fix the issue, check the dvd_frontend in load_firmware_cb(), if it is null, report a warning and just return. [1]: ================================================================== BUG: KASAN: use-after-free in load_firmware_cb+0x1310/0x17a0 Read of size 8 at addr ffff8000d7ca2308 by task kworker/2:3/6504 Call trace: load_firmware_cb+0x1310/0x17a0 request_firmware_work_func+0x128/0x220 process_one_work+0x770/0x1824 worker_thread+0x488/0xea0 kthread+0x300/0x430 ret_from_fork+0x10/0x20 Allocated by task 6504: kzalloc tuner_probe+0xb0/0x1430 i2c_device_probe+0x92c/0xaf0 really_probe+0x678/0xcd0 driver_probe_device+0x280/0x370 __device_attach_driver+0x220/0x330 bus_for_each_drv+0x134/0x1c0 __device_attach+0x1f4/0x410 device_initial_probe+0x20/0x30 bus_probe_device+0x184/0x200 device_add+0x924/0x12c0 device_register+0x24/0x30 i2c_new_device+0x4e0/0xc44 v4l2_i2c_new_subdev_board+0xbc/0x290 v4l2_i2c_new_subdev+0xc8/0x104 em28xx_v4l2_init+0x1dd0/0x3770 Freed by...
4.10.0-14.16~16.04.14.10.0-19.21~16.04.14.10.0-20.22~16.04.14.10.0-21.23~16.04.14.10.0-22.24~16.04.14.10.0-24.28~16.04.14.10.0-26.30~16.04.14.11.0-13.19~16.04.14.11.0-14.20~16.04.14.13.0-16.19~16.04.3+13 more5.0.0-1021.24~18.04.15.0.0-1022.25~18.04.15.0.0-1023.26~18.04.15.0.0-1024.27~18.04.15.0.0-1025.285.0.0-1027.305.3.0-1016.17~18.04.15.3.0-1017.18~18.04.15.3.0-1019.21~18.04.15.3.0-1023.25~18.04.15.3.0-1028.30~18.04.15.3.0-1030.32~18.04.15.3.0-1032.34~18.04.25.3.0-1033.355.3.0-1034.365.3.0-1035.374.15.0-1002.24.15.0-1003.34.15.0-1004.44.15.0-1008.84.15.0-1009.94.15.0-1012.124.15.0-1013.134.15.0-1014.144.15.0-1018.184.15.0-1019.19+34 more5.3.0-1007.8~18.04.15.3.0-1008.9~18.04.15.3.0-1009.10~18.04.15.3.0-1010.11~18.04.15.3.0-1012.13~18.04.15.3.0-1013.14~18.04.15.3.0-1016.17~18.04.15.3.0-1018.19~18.04.15.3.0-1019.20~18.04.15.3.0-1020.21~18.04.1+6 more4.18.0-1006.6~18.04.14.18.0-1007.7~18.04.14.18.0-1008.8~18.04.15.0.0-1012.12~18.04.24.15.0-1001.14.15.0-1003.34.15.0-1005.54.15.0-1006.64.15.0-1008.84.15.0-1009.94.15.0-1010.104.15.0-1014.144.15.0-1015.154.15.0-1017.18+28 more5.3.0-1008.9~18.04.15.3.0-1009.10~18.04.15.3.0-1010.11~18.04.15.3.0-1012.13~18.04.15.3.0-1014.15~18.04.15.3.0-1016.17~18.04.15.3.0-1017.18~18.04.15.3.0-1018.19~18.04.15.3.0-1020.22~18.04.15.3.0-1026.28~18.04.1+3 more4.15.0-1030.324.15.0-1032.344.15.0-1033.354.15.0-1034.364.15.0-1036.384.15.0-1037.394.15.0-1040.424.15.0-1041.434.15.0-1042.444.15.0-1044.46+23 more5.4.0-1025.25~18.04.15.4.0-1027.28~18.04.15.4.0-1029.31~18.04.15.4.0-1030.32~18.04.15.4.0-1032.34~18.04.15.4.0-1033.35~18.04.15.4.0-1035.37~18.04.15.4.0-1036.38~18.04.15.4.0-1037.39~18.04.15.4.0-1039.41~18.04.1+27 moreExploitability
AV:LAC:LPR:LUI:NScope
S:UImpact
C:HI:HA:HCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H