netlink: 20 bytes leftover after parsing attributes in process `syz-executor.1'. ================================================================== BUG: KASAN: use-after-free in __fb_pad_aligned_buffer include/linux/fb.h:674 [inline] BUG: KASAN: use-after-free in bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] BUG: KASAN: use-after-free in bit_putcs+0xd5d/0xf10 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff8880a0864588 by task syz-executor.3/23700 CPU: 1 PID: 23700 Comm: syz-executor.3 Not tainted 4.19.104-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+0x197/0x210 lib/dump_stack.c:118 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report mm/kasan/report.c:412 [inline] kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:396 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430 __fb_pad_aligned_buffer include/linux/fb.h:674 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0xd5d/0xf10 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x42b/0x4f0 drivers/video/fbdev/core/fbcon.c:1320 do_update_region+0x42b/0x6f0 drivers/tty/vt/vt.c:677 redraw_screen+0x602/0x8e0 drivers/tty/vt/vt.c:1013 vc_do_resize+0x118e/0x14a0 drivers/tty/vt/vt.c:1287 vc_resize+0x4d/0x60 drivers/tty/vt/vt.c:1307 vt_ioctl+0x1fe0/0x2530 drivers/tty/vt/vt_ioctl.c:887 tty_ioctl+0x7f3/0x1510 drivers/tty/tty_io.c:2669 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xd5f/0x1380 fs/ioctl.c:688 ksys_ioctl+0xab/0xd0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:710 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c6c9 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:00007f1d9c099c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f1d9c09a6d4 RCX: 000000000045c6c9 RDX: 0000000020000040 RSI: 000000000000560a RDI: 0000000000000008 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000066b R14: 00000000004c9293 R15: 000000000076bf2c Allocated by task 2746: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531 __do_kmalloc_node mm/slab.c:3689 [inline] __kmalloc_node_track_caller+0x51/0x80 mm/slab.c:3703 __kmalloc_reserve.isra.0+0x40/0xf0 net/core/skbuff.c:137 __alloc_skb+0x10b/0x5f0 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:995 [inline] alloc_uevent_skb+0x86/0x220 lib/kobject_uevent.c:288 uevent_net_broadcast_tagged lib/kobject_uevent.c:349 [inline] kobject_uevent_net_broadcast lib/kobject_uevent.c:409 [inline] kobject_uevent_env+0xe5d/0x1170 lib/kobject_uevent.c:590 kobject_uevent+0x20/0x30 lib/kobject_uevent.c:639 device_del+0x6f0/0xb70 drivers/base/core.c:2205 netdev_unregister_kobject+0x19e/0x1f0 net/core/net-sysfs.c:1731 rollback_registered_many+0x6bb/0xda0 net/core/dev.c:8204 unregister_netdevice_many.part.0+0x1b/0x1f0 net/core/dev.c:9294 unregister_netdevice_many+0x3b/0x50 net/core/dev.c:9293 rtnl_delete_link+0xda/0x130 net/core/rtnetlink.c:2760 rtnl_dellink+0x3a7/0x920 net/core/rtnetlink.c:2814 rtnetlink_rcv_msg+0x463/0xb00 net/core/rtnetlink.c:4777 netlink_rcv_skb+0x17d/0x460 net/netlink/af_netlink.c:2454 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:4795 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline] netlink_unicast+0x53a/0x730 net/netlink/af_netlink.c:1343 netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:632 ___sys_sendmsg+0x803/0x920 net/socket.c:2115 __sys_sendmsg+0x105/0x1d0 net/socket.c:2153 __do_sys_sendmsg net/socket.c:2162 [inline] __se_sys_sendmsg net/socket.c:2160 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2160 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 2746: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3503 [inline] kfree+0xcf/0x220 mm/slab.c:3822 skb_free_head+0x99/0xc0 net/core/skbuff.c:554 skb_release_data+0x619/0x8d0 net/core/skbuff.c:574 skb_release_all+0x4d/0x60 net/core/skbuff.c:631 __kfree_skb net/core/skbuff.c:645 [inline] consume_skb net/core/skbuff.c:705 [inline] consume_skb+0xe2/0x390 net/core/skbuff.c:699 netlink_broadcast_filtered+0x316/0xb30 net/netlink/af_netlink.c:1519 netlink_broadcast+0x3a/0x50 net/netlink/af_netlink.c:1541 uevent_net_broadcast_tagged lib/kobject_uevent.c:370 [inline] kobject_uevent_net_broadcast lib/kobject_uevent.c:409 [inline] kobject_uevent_env+0xf44/0x1170 lib/kobject_uevent.c:590 kobject_uevent+0x20/0x30 lib/kobject_uevent.c:639 device_del+0x6f0/0xb70 drivers/base/core.c:2205 netdev_unregister_kobject+0x19e/0x1f0 net/core/net-sysfs.c:1731 rollback_registered_many+0x6bb/0xda0 net/core/dev.c:8204 unregister_netdevice_many.part.0+0x1b/0x1f0 net/core/dev.c:9294 unregister_netdevice_many+0x3b/0x50 net/core/dev.c:9293 rtnl_delete_link+0xda/0x130 net/core/rtnetlink.c:2760 rtnl_dellink+0x3a7/0x920 net/core/rtnetlink.c:2814 rtnetlink_rcv_msg+0x463/0xb00 net/core/rtnetlink.c:4777 netlink_rcv_skb+0x17d/0x460 net/netlink/af_netlink.c:2454 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:4795 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline] netlink_unicast+0x53a/0x730 net/netlink/af_netlink.c:1343 netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:632 ___sys_sendmsg+0x803/0x920 net/socket.c:2115 __sys_sendmsg+0x105/0x1d0 net/socket.c:2153 __do_sys_sendmsg net/socket.c:2162 [inline] __se_sys_sendmsg net/socket.c:2160 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2160 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880a0864540 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 72 bytes inside of 512-byte region [ffff8880a0864540, ffff8880a0864740) The buggy address belongs to the page: page:ffffea0002821900 count:1 mapcount:0 mapping:ffff88812c31c940 index:0xffff8880a08647c0 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffffea000241a088 ffffea0001fd7e88 ffff88812c31c940 raw: ffff8880a08647c0 ffff8880a0864040 0000000100000002 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a0864480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a0864500: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff8880a0864580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a0864600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a0864680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================