audit: type=1804 audit(1547277758.409:288): pid=21186 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor1" name="/root/syzkaller-testdir069138271/syzkaller.MttrCW/414/memory.events" dev="sda1" ino=16490 res=1 ================================================================== BUG: KASAN: use-after-free in xfrm_policy_insert_inexact_list net/xfrm/xfrm_policy.c:1497 [inline] BUG: KASAN: use-after-free in xfrm_policy_inexact_insert+0xbfa/0xda0 net/xfrm/xfrm_policy.c:1202 Read of size 1 at addr ffff888057466b19 by task syz-executor0/21210 CPU: 1 PID: 21210 Comm: syz-executor0 Not tainted 4.20.0+ #17 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+0x1db/0x2d0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 __asan_report_load1_noabort+0x14/0x20 mm/kasan/generic_report.c:132 xfrm_policy_insert_inexact_list net/xfrm/xfrm_policy.c:1497 [inline] xfrm_policy_inexact_insert+0xbfa/0xda0 net/xfrm/xfrm_policy.c:1202 xfrm_policy_insert+0x623/0x910 net/xfrm/xfrm_policy.c:1570 xfrm_add_policy+0x2a1/0x6c0 net/xfrm/xfrm_user.c:1657 xfrm_user_rcv_msg+0x458/0x8d0 net/xfrm/xfrm_user.c:2663 netlink_rcv_skb+0x17d/0x410 net/netlink/af_netlink.c:2477 xfrm_netlink_rcv+0x70/0x90 net/xfrm/xfrm_user.c:2671 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline] netlink_unicast+0x574/0x770 net/netlink/af_netlink.c:1336 netlink_sendmsg+0xa05/0xf90 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg+0xdd/0x130 net/socket.c:631 ___sys_sendmsg+0x7ec/0x910 net/socket.c:2116 __sys_sendmsg+0x112/0x270 net/socket.c:2154 __do_sys_sendmsg net/socket.c:2163 [inline] __se_sys_sendmsg net/socket.c:2161 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457ec9 Code: 6d b7 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 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f7fa06a6c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457ec9 RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7fa06a76d4 R13: 00000000004c5394 R14: 00000000004d8e30 R15: 00000000ffffffff Allocated by task 3464: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] kasan_kmalloc mm/kasan/common.c:482 [inline] kasan_kmalloc+0xcf/0xe0 mm/kasan/common.c:455 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3607 kmalloc include/linux/slab.h:545 [inline] kzalloc include/linux/slab.h:740 [inline] kernfs_iop_get_link fs/kernfs/symlink.c:136 [inline] kernfs_iop_get_link+0x6a/0x680 fs/kernfs/symlink.c:127 vfs_readlink+0x28e/0x4b0 fs/namei.c:4735 do_readlinkat+0x343/0x400 fs/stat.c:409 __do_sys_readlink fs/stat.c:430 [inline] __se_sys_readlink fs/stat.c:427 [inline] __x64_sys_readlink+0x78/0xb0 fs/stat.c:427 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 3464: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:444 kasan_slab_free+0xe/0x10 mm/kasan/common.c:452 __cache_free mm/slab.c:3485 [inline] kfree+0xcf/0x230 mm/slab.c:3804 kfree_link+0x16/0x20 fs/libfs.c:1105 do_delayed_call include/linux/delayed_call.h:28 [inline] vfs_readlink+0x1f1/0x4b0 fs/namei.c:4740 do_readlinkat+0x343/0x400 fs/stat.c:409 __do_sys_readlink fs/stat.c:430 [inline] __se_sys_readlink fs/stat.c:427 [inline] __x64_sys_readlink+0x78/0xb0 fs/stat.c:427 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe audit: type=1804 audit(1547277758.999:289): pid=21191 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=ToMToU comm="syz-executor1" name="/root/syzkaller-testdir069138271/syzkaller.MttrCW/414/memory.events" dev="sda1" ino=16490 res=1 The buggy address belongs to the object at ffff888057466880 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 665 bytes inside of 4096-byte region [ffff888057466880, ffff888057467880) The buggy address belongs to the page: page:ffffea00015d1980 count:1 mapcount:0 mapping:ffff88812c3f0dc0 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea0001a9d308 ffffea00016ab508 ffff88812c3f0dc0 raw: 0000000000000000 ffff888057466880 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888057466a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888057466a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888057466b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888057466b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888057466c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================