================================================================== BUG: KASAN: use-after-free in strlen+0x79/0x90 lib/string.c:525 Read of size 1 at addr ffff8881cf271d08 by task syz-executor.0/20150 CPU: 0 PID: 20150 Comm: syz-executor.0 Not tainted 5.3.0-rc7+ #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+0xca/0x13e lib/dump_stack.c:113 print_address_description+0x6a/0x32c mm/kasan/report.c:351 __kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482 kasan_report+0xe/0x12 mm/kasan/common.c:618 strlen+0x79/0x90 lib/string.c:525 strlen include/linux/string.h:281 [inline] str_to_user+0x27/0x90 drivers/input/evdev.c:802 evdev_do_ioctl drivers/input/evdev.c:1205 [inline] evdev_ioctl_handler+0x1388/0x19e0 drivers/input/evdev.c:1303 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xd2d/0x1330 fs/ioctl.c:696 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718 do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4598e9 Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fee6bdfec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004598e9 RDX: 00000000200002c0 RSI: 0000000080404507 RDI: 0000000000000008 RBP: 000000000075c118 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fee6bdff6d4 R13: 00000000004c1ae8 R14: 00000000004d4e60 R15: 00000000ffffffff Allocated by task 16428: save_stack+0x1b/0x80 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc mm/kasan/common.c:493 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:466 slab_post_alloc_hook mm/slab.h:520 [inline] slab_alloc_node mm/slub.c:2770 [inline] __kmalloc_node_track_caller+0xfc/0x380 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:1055 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1174 [inline] netlink_sendmsg+0x8cd/0xcc0 net/netlink/af_netlink.c:1892 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:657 ___sys_sendmsg+0x803/0x920 net/socket.c:2311 __sys_sendmsg+0xec/0x1b0 net/socket.c:2356 do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 16428: save_stack+0x1b/0x80 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_slab_free+0x130/0x180 mm/kasan/common.c:455 slab_free_hook mm/slub.c:1423 [inline] slab_free_freelist_hook mm/slub.c:1474 [inline] slab_free mm/slub.c:3016 [inline] kfree+0xe4/0x2f0 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+0xd9/0x320 net/core/skbuff.c:832 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline] netlink_unicast+0x4d7/0x690 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x802/0xcc0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:657 ___sys_sendmsg+0x803/0x920 net/socket.c:2311 __sys_sendmsg+0xec/0x1b0 net/socket.c:2356 do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8881cf271b00 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 520 bytes inside of 1024-byte region [ffff8881cf271b00, ffff8881cf271f00) The buggy address belongs to the page: page:ffffea00073c9c00 refcount:1 mapcount:0 mapping:ffff8881da002280 index:0x0 compound_mapcount: 0 flags: 0x200000000010200(slab|head) raw: 0200000000010200 ffffea00073e1b00 0000000800000002 ffff8881da002280 raw: 0000000000000000 00000000000e000e 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881cf271c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881cf271c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881cf271d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881cf271d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881cf271e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================