random: sshd: uninitialized urandom read (32 bytes read, 123 bits of entropy available) ================================================================== BUG: KASAN: slab-out-of-bounds in strnlen+0xc1/0xd0 lib/string.c:498 Read of size 1 at addr ffff8801d13080d0 by task syzkaller046937/3318 CPU: 1 PID: 3318 Comm: syzkaller046937 Not tainted 4.4.113-ge70c132 #27 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000000 5d8b7e24007d1d61 ffff8801d0ad75c0 ffffffff81d0278d ffffea000744c200 ffff8801d13080d0 0000000000000000 ffff8801d13080d0 ffff8801d0ad7890 ffff8801d0ad75f8 ffffffff814fd053 ffff8801d13080d0 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x124 lib/dump_stack.c:51 [] print_address_description+0x73/0x260 mm/kasan/report.c:252 [] kasan_report_error mm/kasan/report.c:351 [inline] [] kasan_report+0x285/0x370 mm/kasan/report.c:408 [] __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:426 [] strnlen+0xc1/0xd0 lib/string.c:498 [] string.isra.4+0x4c/0x240 lib/vsprintf.c:518 [] vsnprintf+0x766/0x15f0 lib/vsprintf.c:1907 [] __request_module+0x14f/0x810 kernel/kmod.c:146 [] xt_request_find_target+0x8b/0xb0 net/netfilter/x_tables.c:255 [] check_compat_entry_size_and_hooks net/ipv4/netfilter/ip_tables.c:1490 [inline] [] translate_compat_table+0x568/0x1760 net/ipv4/netfilter/ip_tables.c:1582 [] ? 0xffffffff810002b8 [] compat_do_replace.isra.15+0x1f1/0x410 net/ipv4/netfilter/ip_tables.c:1690 [] compat_do_ipt_set_ctl+0x106/0x150 net/ipv4/netfilter/ip_tables.c:1721 [] 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:1255 [] compat_udp_setsockopt+0x45/0x80 net/ipv4/udp.c:2164 [] compat_sock_common_setsockopt+0xb2/0x140 net/core/sock.c:2670 [] C_SYSC_setsockopt net/compat.c:384 [inline] [] compat_SyS_setsockopt+0x149/0x290 net/compat.c:367 [] do_syscall_32_irqs_on arch/x86/entry/common.c:390 [inline] [] do_fast_syscall_32+0x314/0x890 arch/x86/entry/common.c:457 [] sysenter_flags_fixed+0xd/0x17 Allocated by task 3318: [] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63 [] save_stack+0x43/0xd0 mm/kasan/kasan.c:512 [] set_track mm/kasan/kasan.c:524 [inline] [] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:616 [] __kmalloc+0x124/0x320 mm/slub.c:3613 [] kmalloc include/linux/slab.h:481 [inline] [] xt_alloc_table_info+0x71/0x100 net/netfilter/x_tables.c:911 [] compat_do_replace.isra.15+0x16b/0x410 net/ipv4/netfilter/ip_tables.c:1679 [] compat_do_ipt_set_ctl+0x106/0x150 net/ipv4/netfilter/ip_tables.c:1721 [] 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:1255 [] compat_udp_setsockopt+0x45/0x80 net/ipv4/udp.c:2164 [] compat_sock_common_setsockopt+0xb2/0x140 net/core/sock.c:2670 [] C_SYSC_setsockopt net/compat.c:384 [inline] [] compat_SyS_setsockopt+0x149/0x290 net/compat.c:367 [] do_syscall_32_irqs_on arch/x86/entry/common.c:390 [inline] [] do_fast_syscall_32+0x314/0x890 arch/x86/entry/common.c:457 [] sysenter_flags_fixed+0xd/0x17 Freed by task 1799: [] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63 [] save_stack+0x43/0xd0 mm/kasan/kasan.c:512 [] set_track mm/kasan/kasan.c:524 [inline] [] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:589 [] slab_free_hook mm/slub.c:1383 [inline] [] slab_free_freelist_hook mm/slub.c:1405 [inline] [] slab_free mm/slub.c:2859 [inline] [] kfree+0xfc/0x300 mm/slub.c:3749 [] inode_doinit_with_dentry+0xa05/0x1b80 security/selinux/hooks.c:1416 [] selinux_d_instantiate+0x27/0x40 security/selinux/hooks.c:5591 [] security_d_instantiate+0x5a/0xe0 security/security.c:1120 [] d_splice_alias+0x17b/0x680 fs/dcache.c:2852 [] ext4_lookup+0x2d2/0x3f0 fs/ext4/namei.c:1621 [] lookup_real+0x98/0x100 fs/namei.c:1519 [] __lookup_hash+0xea/0x100 fs/namei.c:1537 [] lookup_slow fs/namei.c:1651 [inline] [] walk_component+0x8f4/0xff0 fs/namei.c:1763 [] lookup_last fs/namei.c:2132 [inline] [] path_lookupat+0x192/0x3f0 fs/namei.c:2149 [] filename_lookup+0x197/0x3b0 fs/namei.c:2183 [] user_path_at_empty+0x40/0x50 fs/namei.c:2357 [] user_path_at include/linux/namei.h:52 [inline] [] vfs_fstatat+0xc6/0x170 fs/stat.c:106 [] vfs_stat fs/stat.c:123 [inline] [] SYSC_newstat+0x86/0x100 fs/stat.c:270 [] SyS_newstat+0x1d/0x30 fs/stat.c:266 [] entry_SYSCALL_64_fastpath+0x1c/0x98 The buggy address belongs to the object at ffff8801d1308000 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 208 bytes inside of 256-byte region [ffff8801d1308000, ffff8801d1308100) The buggy address belongs to the page: PANIC: double fault, error_code: 0x0 CPU: 1 PID: 3318 Comm: syzkaller046937 Not tainted 4.4.113-ge70c132 #27 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801d15b2f80 task.stack: ffff8801d0ad0000 RIP: 0010:[] [] dump_page_badflags+0x12/0x250 mm/debug.c:84 RSP: 0018:ffff880100000000 EFLAGS: 00010046 RAX: ffff8801d15b2f80 RBX: ffffea000744c200 RCX: ffffffff8148f8d0 RDX: 0000000000000000 RSI: ffffffff838a8de0 RDI: ffffea000744c200 RBP: ffff880100000020 R08: 0000000000000001 R09: 0000000000000000 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1734 at kernel/locking/lockdep.c:973 lock_accessed kernel/locking/lockdep.c:973 [inline]() WARNING: CPU: 0 PID: 1734 at kernel/locking/lockdep.c:973 __bfs+0x2c4/0x5d0 kernel/locking/lockdep.c:1040()