================================================================== BUG: KASAN: use-after-free in tomoyo_get_socket_name security/tomoyo/realpath.c:238 [inline] BUG: KASAN: use-after-free in tomoyo_realpath_from_path+0x719/0x7b0 security/tomoyo/realpath.c:284 Read of size 4 at addr ffff8880613aef60 by task syz-executor.4/2878 CPU: 1 PID: 2878 Comm: syz-executor.4 Not tainted 5.5.0-rc1-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.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:639 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:134 tomoyo_get_socket_name security/tomoyo/realpath.c:238 [inline] tomoyo_realpath_from_path+0x719/0x7b0 security/tomoyo/realpath.c:284 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x2a3/0x3e0 security/tomoyo/file.c:771 tomoyo_file_open security/tomoyo/tomoyo.c:319 [inline] tomoyo_file_open+0xa9/0xd0 security/tomoyo/tomoyo.c:314 security_file_open+0x71/0x300 security/security.c:1497 do_dentry_open+0x37a/0x1380 fs/open.c:784 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3420 [inline] path_openat+0x10df/0x4500 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_sys_open+0x3fe/0x5d0 fs/open.c:1097 __do_sys_open fs/open.c:1115 [inline] __se_sys_open fs/open.c:1110 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1110 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4146a1 Code: 75 14 b8 02 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 19 00 00 c3 48 83 ec 08 e8 0a fa ff ff 48 89 04 24 b8 02 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fa ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007f50e0ca1bb0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00000000004146a1 RDX: fffffffffffffffa RSI: 0000000000000000 RDI: 00007f50e0ca1bd0 RBP: 000000000075bf20 R08: 0000000000000000 R09: 000000000000000f R10: 0000000000000004 R11: 0000000000000293 R12: 00007f50e0ca26d4 R13: 00000000004cb278 R14: 00000000004e4870 R15: 00000000ffffffff Allocated by task 2878: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc mm/kasan/common.c:513 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:521 slab_post_alloc_hook mm/slab.h:584 [inline] slab_alloc mm/slab.c:3320 [inline] kmem_cache_alloc+0x121/0x710 mm/slab.c:3484 sk_prot_alloc+0x67/0x310 net/core/sock.c:1597 sk_alloc+0x39/0xfd0 net/core/sock.c:1657 inet6_create net/ipv6/af_inet6.c:180 [inline] inet6_create+0x35b/0xf70 net/ipv6/af_inet6.c:107 __sock_create+0x3ce/0x730 net/socket.c:1420 sock_create net/socket.c:1471 [inline] __sys_socket+0x103/0x220 net/socket.c:1513 __do_sys_socket net/socket.c:1522 [inline] __se_sys_socket net/socket.c:1520 [inline] __x64_sys_socket+0x73/0xb0 net/socket.c:1520 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 2876: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:335 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474 kasan_slab_free+0xe/0x10 mm/kasan/common.c:483 __cache_free mm/slab.c:3426 [inline] kmem_cache_free+0x86/0x320 mm/slab.c:3694 sk_prot_free net/core/sock.c:1638 [inline] __sk_destruct+0x4e6/0x7f0 net/core/sock.c:1724 sk_destruct+0xd5/0x110 net/core/sock.c:1739 __sk_free+0xfb/0x360 net/core/sock.c:1750 sk_free+0x83/0xb0 net/core/sock.c:1761 sock_put include/net/sock.h:1729 [inline] sk_common_release+0x268/0x390 net/core/sock.c:3200 l2tp_ip6_close+0x230/0x2c0 net/l2tp/l2tp_ip6.c:244 inet_release+0xed/0x200 net/ipv4/af_inet.c:427 inet6_release+0x53/0x80 net/ipv6/af_inet6.c:470 __sock_release+0xce/0x280 net/socket.c:592 sock_close+0x1e/0x30 net/socket.c:1270 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath arch/x86/entry/common.c:278 [inline] do_syscall_64+0x676/0x790 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880613aec00 which belongs to the cache L2TP/IPv6(81:syz4) of size 1520 The buggy address is located 864 bytes inside of 1520-byte region [ffff8880613aec00, ffff8880613af1f0) The buggy address belongs to the page: page:ffffea000184eb80 refcount:1 mapcount:0 mapping:ffff8880934f31c0 index:0x0 compound_mapcount: 0 raw: 00fffe0000010200 ffffea0002819888 ffffea0001522e88 ffff8880934f31c0 raw: 0000000000000000 ffff8880613ae580 0000000100000004 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880613aee00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880613aee80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880613aef00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880613aef80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880613af000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================