================================================================== BUG: KASAN: use-after-free in strlen+0x79/0x90 lib/string.c:527 Read of size 1 at addr ffff8881d2c01208 by task syz-executor.2/8696 CPU: 1 PID: 8696 Comm: syz-executor.2 Not tainted 5.5.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xef/0x16e lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd3/0x314 mm/kasan/report.c:374 __kasan_report.cold+0x37/0x85 mm/kasan/report.c:506 kasan_report+0xe/0x20 mm/kasan/common.c:639 strlen+0x79/0x90 lib/string.c:527 strlen include/linux/string.h:302 [inline] str_to_user+0x27/0x90 drivers/input/evdev.c:783 evdev_do_ioctl drivers/input/evdev.c:1186 [inline] evdev_ioctl_handler+0x130a/0x19f0 drivers/input/evdev.c:1284 vfs_ioctl fs/ioctl.c:47 [inline] file_ioctl fs/ioctl.c:545 [inline] do_vfs_ioctl+0x90c/0x1420 fs/ioctl.c:732 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:749 __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:754 do_syscall_64+0xb6/0x5a0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b399 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f1596290c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f15962916d4 RCX: 000000000045b399 RDX: 0000000020000280 RSI: 0000000080404507 RDI: 000000000000000b RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000002c6 R14: 00000000004c3cdc R15: 000000000075bfd4 Allocated by task 4436: save_stack+0x1b/0x80 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc mm/kasan/common.c:513 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:486 slab_post_alloc_hook mm/slab.h:584 [inline] slab_alloc_node mm/slub.c:2759 [inline] __kmalloc_node_track_caller+0xfc/0x3b0 mm/slub.c:4365 __kmalloc_reserve.isra.0+0x39/0xe0 net/core/skbuff.c:141 __alloc_skb+0xef/0x5a0 net/core/skbuff.c:209 alloc_skb include/linux/skbuff.h:1049 [inline] alloc_uevent_skb+0x7b/0x210 lib/kobject_uevent.c:289 uevent_net_broadcast_untagged lib/kobject_uevent.c:325 [inline] kobject_uevent_net_broadcast lib/kobject_uevent.c:408 [inline] kobject_uevent_env+0xac7/0x1470 lib/kobject_uevent.c:592 device_del+0x847/0xd30 drivers/base/core.c:2674 hid_remove_device drivers/hid/hid-core.c:2465 [inline] hid_destroy_device+0xe1/0x150 drivers/hid/hid-core.c:2484 usbhid_disconnect+0x9f/0xe0 drivers/hid/usbhid/hid-core.c:1413 usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423 __device_release_driver drivers/base/dd.c:1134 [inline] device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1165 bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:532 device_del+0x481/0xd30 drivers/base/core.c:2664 usb_disable_device+0x23d/0x790 drivers/usb/core/message.c:1237 usb_disconnect+0x293/0x900 drivers/usb/core/hub.c:2201 hub_port_connect drivers/usb/core/hub.c:5036 [inline] hub_port_connect_change drivers/usb/core/hub.c:5325 [inline] port_event drivers/usb/core/hub.c:5471 [inline] hub_event+0x1a1d/0x4300 drivers/usb/core/hub.c:5553 process_one_work+0x945/0x15c0 kernel/workqueue.c:2264 worker_thread+0x96/0xe20 kernel/workqueue.c:2410 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Freed by task 239: save_stack+0x1b/0x80 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:335 [inline] __kasan_slab_free+0x117/0x160 mm/kasan/common.c:474 slab_free_hook mm/slub.c:1425 [inline] slab_free_freelist_hook mm/slub.c:1458 [inline] slab_free mm/slub.c:3005 [inline] kfree+0xd5/0x300 mm/slub.c:3957 skb_free_head+0x8b/0xa0 net/core/skbuff.c:591 skb_release_data+0x41f/0x7c0 net/core/skbuff.c:611 skb_release_all+0x46/0x60 net/core/skbuff.c:665 __kfree_skb net/core/skbuff.c:679 [inline] consume_skb net/core/skbuff.c:838 [inline] consume_skb+0xf3/0x3c0 net/core/skbuff.c:832 skb_free_datagram+0x16/0xf0 net/core/datagram.c:328 netlink_recvmsg+0x65e/0xee0 net/netlink/af_netlink.c:1996 sock_recvmsg_nosec net/socket.c:873 [inline] sock_recvmsg net/socket.c:891 [inline] sock_recvmsg+0xca/0x110 net/socket.c:887 ____sys_recvmsg+0x202/0x580 net/socket.c:2553 ___sys_recvmsg+0xe4/0x150 net/socket.c:2595 __sys_recvmsg+0xe9/0x1b0 net/socket.c:2629 do_syscall_64+0xb6/0x5a0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8881d2c01000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 520 bytes inside of 1024-byte region [ffff8881d2c01000, ffff8881d2c01400) The buggy address belongs to the page: page:ffffea00074b0000 refcount:1 mapcount:0 mapping:ffff8881da002280 index:0x0 compound_mapcount: 0 raw: 0200000000010200 0000000000000000 0000000100000001 ffff8881da002280 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881d2c01100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881d2c01180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881d2c01200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881d2c01280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881d2c01300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================