================================================================== BUG: KASAN: slab-out-of-bounds in string+0x1e8/0x200 lib/vsprintf.c:592 Read of size 1 at addr ffff8801c94d50d0 by task syzkaller264309/3332 CPU: 0 PID: 3332 Comm: syzkaller264309 Not tainted 4.9.78-ge9dabe6 #28 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801cdff7610 ffffffff81d943a9 ffffea0007253540 ffff8801c94d50d0 0000000000000000 ffff8801c94d50d0 ffff8801cdff786c ffff8801cdff7648 ffffffff8153dc23 ffff8801c94d50d0 0000000000000001 0000000000000000 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] print_address_description+0x73/0x280 mm/kasan/report.c:252 [] kasan_report_error mm/kasan/report.c:351 [inline] [] kasan_report+0x275/0x360 mm/kasan/report.c:408 [] __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:426 [] string+0x1e8/0x200 lib/vsprintf.c:592 [] vsnprintf+0x7ad/0x16d0 lib/vsprintf.c:2044 [] __request_module+0x14f/0x750 kernel/kmod.c:146 [] xt_request_find_target+0x8b/0xb0 net/netfilter/x_tables.c:256 [] check_compat_entry_size_and_hooks net/ipv4/netfilter/ip_tables.c:1342 [inline] [] translate_compat_table+0x568/0x1760 net/ipv4/netfilter/ip_tables.c:1431 [] ? 0xffffffff810002b8 [] compat_do_replace.isra.15+0x1a7/0x3a0 net/ipv4/netfilter/ip_tables.c:1534 [] compat_do_ipt_set_ctl+0x106/0x150 net/ipv4/netfilter/ip_tables.c:1563 [] compat_nf_sockopt net/netfilter/nf_sockopt.c:143 [inline] [] compat_nf_setsockopt+0x88/0x130 net/netfilter/nf_sockopt.c:155 [] compat_ip_setsockopt+0x9d/0xf0 net/ipv4/ip_sockglue.c:1277 [] compat_udp_setsockopt+0x45/0x80 net/ipv4/udp.c:2093 [] compat_sock_common_setsockopt+0xb2/0x140 net/core/sock.c:2717 [] C_SYSC_setsockopt net/compat.c:398 [inline] [] compat_SyS_setsockopt+0x149/0x290 net/compat.c:381 [] do_syscall_32_irqs_on arch/x86/entry/common.c:322 [inline] [] do_fast_syscall_32+0x2f7/0x890 arch/x86/entry/common.c:384 [] entry_SYSENTER_compat+0x74/0x83 arch/x86/entry/entry_64_compat.S:127 Allocated by task 3332: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack+0x43/0xd0 mm/kasan/kasan.c:505 set_track mm/kasan/kasan.c:517 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:609 __kmalloc+0x11d/0x310 mm/slub.c:3741 kmalloc include/linux/slab.h:495 [inline] xt_alloc_table_info+0x71/0x100 net/netfilter/x_tables.c:959 compat_do_replace.isra.15+0x116/0x3a0 net/ipv4/netfilter/ip_tables.c:1523 compat_do_ipt_set_ctl+0x106/0x150 net/ipv4/netfilter/ip_tables.c:1563 compat_nf_sockopt net/netfilter/nf_sockopt.c:143 [inline] compat_nf_setsockopt+0x88/0x130 net/netfilter/nf_sockopt.c:155 compat_ip_setsockopt+0x9d/0xf0 net/ipv4/ip_sockglue.c:1277 compat_udp_setsockopt+0x45/0x80 net/ipv4/udp.c:2093 compat_sock_common_setsockopt+0xb2/0x140 net/core/sock.c:2717 C_SYSC_setsockopt net/compat.c:398 [inline] compat_SyS_setsockopt+0x149/0x290 net/compat.c:381 do_syscall_32_irqs_on arch/x86/entry/common.c:322 [inline] do_fast_syscall_32+0x2f7/0x890 arch/x86/entry/common.c:384 entry_SYSENTER_compat+0x74/0x83 arch/x86/entry/entry_64_compat.S:127 Freed by task 1822: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack+0x43/0xd0 mm/kasan/kasan.c:505 set_track mm/kasan/kasan.c:517 [inline] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:582 slab_free_hook mm/slub.c:1355 [inline] slab_free_freelist_hook mm/slub.c:1377 [inline] slab_free mm/slub.c:2958 [inline] kfree+0x103/0x300 mm/slub.c:3878 seq_release+0x59/0x70 fs/seq_file.c:372 kernfs_fop_release+0xcb/0x140 fs/kernfs/file.c:742 __fput+0x28c/0x6e0 fs/file_table.c:208 ____fput+0x15/0x20 fs/file_table.c:244 task_work_run+0x115/0x190 kernel/task_work.c:116 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0xfc/0x120 arch/x86/entry/common.c:160 prepare_exit_to_usermode arch/x86/entry/common.c:190 [inline] syscall_return_slowpath+0x1a0/0x1e0 arch/x86/entry/common.c:259 entry_SYSCALL_64_fastpath+0xe6/0xe8 The buggy address belongs to the object at ffff8801c94d5000 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 208 bytes inside of 256-byte region [ffff8801c94d5000, ffff8801c94d5100) The buggy address belongs to the page: page:ffffea0007253540 count:1 mapcount:0 mapping: (null) index:0xffff8801c94d58c0 flags: 0x8000000000000080(slab) page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801c94d4f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801c94d5000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8801c94d5080: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc ^ ffff8801c94d5100: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff8801c94d5180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================