================================================================== BUG: KASAN: slab-out-of-bounds in vsscanf+0x2666/0x2ef0 lib/vsprintf.c:3275 Read of size 1 at addr ffff8880a77aec82 by task syz-executor.1/15010 CPU: 0 PID: 15010 Comm: syz-executor.1 Not tainted 5.7.0-rc2-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+0x1e9/0x30e lib/dump_stack.c:118 print_address_description+0x74/0x5c0 mm/kasan/report.c:382 __kasan_report+0x103/0x1a0 mm/kasan/report.c:511 kasan_report+0x4d/0x80 mm/kasan/common.c:625 Allocated by task 15010: save_stack mm/kasan/common.c:49 [inline] set_track mm/kasan/common.c:57 [inline] __kasan_kmalloc+0x114/0x160 mm/kasan/common.c:495 __do_kmalloc mm/slab.c:3656 [inline] __kmalloc_track_caller+0x249/0x320 mm/slab.c:3671 memdup_user_nul+0x26/0xf0 mm/util.c:259 smk_set_cipso+0xff/0x6a0 security/smack/smackfs.c:859 __vfs_write+0xa7/0x710 fs/read_write.c:495 __kernel_write+0x120/0x350 fs/read_write.c:516 write_pipe_buf+0xf9/0x150 fs/splice.c:809 splice_from_pipe_feed fs/splice.c:512 [inline] __splice_from_pipe+0x329/0x870 fs/splice.c:636 splice_from_pipe fs/splice.c:671 [inline] default_file_splice_write+0x112/0x1b0 fs/splice.c:821 splice_direct_to_actor+0x482/0xb40 fs/splice.c:992 do_splice_direct+0x201/0x340 fs/splice.c:1080 do_sendfile+0x809/0xfe0 fs/read_write.c:1521 __do_sys_sendfile64 fs/read_write.c:1582 [inline] __se_sys_sendfile64 fs/read_write.c:1568 [inline] __x64_sys_sendfile64+0x164/0x1a0 fs/read_write.c:1568 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Freed by task 14045: save_stack mm/kasan/common.c:49 [inline] set_track mm/kasan/common.c:57 [inline] kasan_set_free_info mm/kasan/common.c:317 [inline] __kasan_slab_free+0x125/0x190 mm/kasan/common.c:456 __cache_free mm/slab.c:3426 [inline] kfree+0x10a/0x220 mm/slab.c:3757 dccp_feat_val_destructor net/dccp/feat.c:383 [inline] dccp_feat_entry_destructor net/dccp/feat.c:412 [inline] dccp_feat_list_purge+0x13b/0x220 net/dccp/feat.c:544 dccp_v6_destroy_sock+0x11/0x20 net/dccp/ipv6.c:1018 inet_csk_destroy_sock+0x157/0x3e0 net/ipv4/inet_connection_sock.c:876 dccp_close+0xb6e/0x1240 net/dccp/proto.c:1083 inet_release+0x135/0x180 net/ipv4/af_inet.c:427 __sock_release net/socket.c:605 [inline] sock_close+0xd8/0x260 net/socket.c:1283 __fput+0x2ed/0x750 fs/file_table.c:280 task_work_run+0x147/0x1d0 kernel/task_work.c:123 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop arch/x86/entry/common.c:165 [inline] prepare_exit_to_usermode+0x48e/0x600 arch/x86/entry/common.c:196 entry_SYSCALL_64_after_hwframe+0x49/0xb3 The buggy address belongs to the object at ffff8880a77aec80 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 2 bytes inside of 32-byte region [ffff8880a77aec80, ffff8880a77aeca0) The buggy address belongs to the page: page:ffffea00029deb80 refcount:1 mapcount:0 mapping:000000002905434c index:0xffff8880a77aefc1 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00028d9988 ffffea0002284648 ffff8880aa4001c0 raw: ffff8880a77aefc1 ffff8880a77ae000 000000010000003d 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a77aeb80: 05 fc fc fc fc fc fc fc 06 fc fc fc fc fc fc fc ffff8880a77aec00: fb fb fb fb fc fc fc fc 00 00 fc fc fc fc fc fc >ffff8880a77aec80: 02 fc fc fc fc fc fc fc 00 00 00 03 fc fc fc fc ^ ffff8880a77aed00: fb fb fb fb fc fc fc fc 00 00 01 fc fc fc fc fc ffff8880a77aed80: 00 00 00 00 fc fc fc fc 00 00 07 fc fc fc fc fc ==================================================================