CVE-2022-50578

In the Linux kernel, the following vulnerability has been resolved: class: fix possible memory leak in __class_register() If class_add_groups() returns error, the 'cp->subsys' need be unregister, and the 'cp' need be freed. We can not call kset_unregister() here, because the 'cls' will be freed in callback function class_release() and it's also freed in caller's error path, it will cause double free. So fix this by calling kobject_del() and kfree_const(name) to cleanup kobject. Besides, call kfree() to free the 'cp'. Fault injection test can trigger this: unreferenced object 0xffff888102fa8190 (size 8): comm "modprobe", pid 502, jiffies 4294906074 (age 49.296s) hex dump (first 8 bytes): 70 6b 74 63 64 76 64 00 pktcdvd. backtrace: [ ] __kmalloc_track_caller+0x1ae/0x320 [ ] kstrdup+0x3a/0x70 [ ] kstrdup_const+0x68/0x80 [ ] kvasprintf_const+0x10b/0x190 [ ] kobject_set_name_vargs+0x56/0x150 [ ] kobject_set_name+0xab/0xe0 [ ] __class_register+0x15c/0x49a unreferenced object 0xffff888037274000 (size 1024): comm "modprobe", pid 502, jiffies 4294906074 (age 49.296s) hex dump (first 32 bytes): 00 40 27 37 80 88 ff ff 00 40 27 37 80 88 ff ff .@'7.....@'7.... 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N.......... backtrace: [ ] kmem_cache_alloc_trace+0x17c/0x2f0 [ ] __class_register+0x86/0x49a