CVE-2023-53138

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> net: caif: Fix use-after-free in cfusbl_device_notify()<br /> <br /> syzbot reported use-after-free in cfusbl_device_notify() [1]. This<br /> causes a stack trace like below:<br /> <br /> BUG: KASAN: use-after-free in cfusbl_device_notify+0x7c9/0x870 net/caif/caif_usb.c:138<br /> Read of size 8 at addr ffff88807ac4e6f0 by task kworker/u4:6/1214<br /> <br /> CPU: 0 PID: 1214 Comm: kworker/u4:6 Not tainted 5.19.0-rc3-syzkaller-00146-g92f20ff72066 #0<br /> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011<br /> Workqueue: netns cleanup_net<br /> Call Trace:<br /> <br /> __dump_stack lib/dump_stack.c:88 [inline]<br /> dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106<br /> print_address_description.constprop.0.cold+0xeb/0x467 mm/kasan/report.c:313<br /> print_report mm/kasan/report.c:429 [inline]<br /> kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491<br /> cfusbl_device_notify+0x7c9/0x870 net/caif/caif_usb.c:138<br /> notifier_call_chain+0xb5/0x200 kernel/notifier.c:87<br /> call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1945<br /> call_netdevice_notifiers_extack net/core/dev.c:1983 [inline]<br /> call_netdevice_notifiers net/core/dev.c:1997 [inline]<br /> netdev_wait_allrefs_any net/core/dev.c:10227 [inline]<br /> netdev_run_todo+0xbc0/0x10f0 net/core/dev.c:10341<br /> default_device_exit_batch+0x44e/0x590 net/core/dev.c:11334<br /> ops_exit_list+0x125/0x170 net/core/net_namespace.c:167<br /> cleanup_net+0x4ea/0xb00 net/core/net_namespace.c:594<br /> process_one_work+0x996/0x1610 kernel/workqueue.c:2289<br /> worker_thread+0x665/0x1080 kernel/workqueue.c:2436<br /> kthread+0x2e9/0x3a0 kernel/kthread.c:376<br /> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302<br /> <br /> <br /> When unregistering a net device, unregister_netdevice_many_notify()<br /> sets the device&amp;#39;s reg_state to NETREG_UNREGISTERING, calls notifiers<br /> with NETDEV_UNREGISTER, and adds the device to the todo list.<br /> <br /> Later on, devices in the todo list are processed by netdev_run_todo().<br /> netdev_run_todo() waits devices&amp;#39; reference count become 1 while<br /> rebdoadcasting NETDEV_UNREGISTER notification.<br /> <br /> When cfusbl_device_notify() is called with NETDEV_UNREGISTER multiple<br /> times, the parent device might be freed. This could cause UAF.<br /> Processing NETDEV_UNREGISTER multiple times also causes inbalance of<br /> reference count for the module.<br /> <br /> This patch fixes the issue by accepting only first NETDEV_UNREGISTER<br /> notification.