netlink: 20 bytes leftover after parsing attributes in process `syz-executor3'. PF_BRIDGE: br_mdb_parse() with non-bridge ================================================================== BUG: KASAN: use-after-free in sock_net_uid include/net/sock.h:1733 [inline] BUG: KASAN: use-after-free in ip6_route_me_harder+0x9d8/0xc00 net/ipv6/netfilter.c:26 Read of size 4 at addr ffff8801b36a7170 by task syz-executor2/967 netlink: 20 bytes leftover after parsing attributes in process `syz-executor3'. CPU: 0 PID: 967 Comm: syz-executor2 Not tainted 4.16.0-rc2+ #250 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 PF_BRIDGE: br_mdb_parse() with non-bridge print_address_description+0x73/0x250 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report+0x23b/0x360 mm/kasan/report.c:412 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432 sock_net_uid include/net/sock.h:1733 [inline] ip6_route_me_harder+0x9d8/0xc00 net/ipv6/netfilter.c:26 nf_nat_ipv6_local_fn+0x2a4/0x5d0 net/ipv6/netfilter/nf_nat_l3proto_ipv6.c:414 ip6table_nat_local_fn+0x2c/0x40 net/ipv6/netfilter/ip6table_nat.c:69 nf_hook_entry_hookfn include/linux/netfilter.h:120 [inline] nf_hook_slow+0xba/0x1a0 net/netfilter/core.c:483 nf_hook include/linux/netfilter.h:243 [inline] NF_HOOK include/linux/netfilter.h:286 [inline] ip6_xmit+0x10ec/0x2260 net/ipv6/ip6_output.c:277 tcp_v6_send_synack+0x57b/0xaa0 net/ipv6/tcp_ipv6.c:490 tcp_conn_request+0x26fd/0x3660 net/ipv4/tcp_input.c:6335 tcp_v6_conn_request+0x212/0x270 net/ipv6/tcp_ipv6.c:1021 tcp_rcv_state_process+0x92a/0x4760 net/ipv4/tcp_input.c:5842 tcp_v6_do_rcv+0x739/0x1250 net/ipv6/tcp_ipv6.c:1331 tcp_v6_rcv+0x25a0/0x2d40 net/ipv6/tcp_ipv6.c:1521 ip6_input_finish+0x37e/0x17a0 net/ipv6/ip6_input.c:284 NF_HOOK include/linux/netfilter.h:288 [inline] ip6_input+0xdb/0x560 net/ipv6/ip6_input.c:327 dst_input include/net/dst.h:449 [inline] ip6_rcv_finish+0x297/0x8c0 net/ipv6/ip6_input.c:71 NF_HOOK include/linux/netfilter.h:288 [inline] ipv6_rcv+0xf37/0x1fa0 net/ipv6/ip6_input.c:208 __netif_receive_skb_core+0x1a41/0x3460 net/core/dev.c:4554 __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4619 netif_receive_skb_internal+0x10b/0x670 net/core/dev.c:4693 netif_receive_skb+0xae/0x390 net/core/dev.c:4717 tun_rx_batched.isra.52+0x5ee/0x870 drivers/net/tun.c:1556 tun_get_user+0x25a5/0x3810 drivers/net/tun.c:1957 tun_chr_write_iter+0xbd/0x1c0 drivers/net/tun.c:1985 call_write_iter include/linux/fs.h:1781 [inline] do_iter_readv_writev+0x55c/0x830 fs/read_write.c:653 do_iter_write+0x154/0x540 fs/read_write.c:932 vfs_writev+0x18a/0x340 fs/read_write.c:977 do_writev+0xfc/0x2a0 fs/read_write.c:1012 SYSC_writev fs/read_write.c:1085 [inline] SyS_writev+0x27/0x30 fs/read_write.c:1082 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x453c41 RSP: 002b:00007f45ea349ba0 EFLAGS: 00000293 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 000000000000004a RCX: 0000000000453c41 RDX: 0000000000000001 RSI: 00007f45ea349bf0 RDI: 00000000000000fc RBP: 0000000020000100 R08: 00000000000000fc R09: 0000000000000000 R10: 000000000000004a R11: 0000000000000293 R12: 00000000ffffffff R13: 0000000000000627 R14: 00000000006f9448 R15: 0000000000000000 Allocated by task 31091: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:552 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489 kmem_cache_alloc_node+0x144/0x760 mm/slab.c:3631 __alloc_skb+0xf1/0x780 net/core/skbuff.c:193 alloc_skb_fclone include/linux/skbuff.h:1028 [inline] sk_stream_alloc_skb+0x126/0x9a0 net/ipv4/tcp.c:867 tso_fragment net/ipv4/tcp_output.c:1870 [inline] tcp_write_xmit+0x1caf/0x5430 net/ipv4/tcp_output.c:2364 __tcp_push_pending_frames+0xa0/0x250 net/ipv4/tcp_output.c:2546 tcp_push_pending_frames include/net/tcp.h:1681 [inline] tcp_data_snd_check net/ipv4/tcp_input.c:5023 [inline] tcp_rcv_established+0xb3c/0x1be0 net/ipv4/tcp_input.c:5473 tcp_v4_do_rcv+0x2ab/0x7d0 net/ipv4/tcp_ipv4.c:1462 sk_backlog_rcv include/net/sock.h:909 [inline] __release_sock+0x124/0x360 net/core/sock.c:2275 release_sock+0xa4/0x2a0 net/core/sock.c:2790 tcp_sendmsg+0x3a/0x50 net/ipv4/tcp.c:1437 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xca/0x110 net/socket.c:639 SYSC_sendto+0x361/0x5c0 net/socket.c:1748 SyS_sendto+0x40/0x50 net/socket.c:1716 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 31091: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527 __cache_free mm/slab.c:3485 [inline] kmem_cache_free+0x83/0x2a0 mm/slab.c:3743 kfree_skbmem+0xdd/0x1d0 net/core/skbuff.c:603 __kfree_skb+0x1d/0x20 net/core/skbuff.c:642 sk_wmem_free_skb include/net/sock.h:1420 [inline] tcp_rtx_queue_unlink_and_free include/net/tcp.h:1673 [inline] tcp_clean_rtx_queue net/ipv4/tcp_input.c:3118 [inline] tcp_ack+0x1bad/0x51a0 net/ipv4/tcp_input.c:3612 tcp_rcv_established+0x8d1/0x1be0 net/ipv4/tcp_input.c:5462 tcp_v4_do_rcv+0x2ab/0x7d0 net/ipv4/tcp_ipv4.c:1462 sk_backlog_rcv include/net/sock.h:909 [inline] __release_sock+0x124/0x360 net/core/sock.c:2275 release_sock+0xa4/0x2a0 net/core/sock.c:2790 tcp_sendmsg+0x3a/0x50 net/ipv4/tcp.c:1437 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xca/0x110 net/socket.c:639 SYSC_sendto+0x361/0x5c0 net/socket.c:1748 SyS_sendto+0x40/0x50 net/socket.c:1716 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff8801b36a7040 which belongs to the cache skbuff_fclone_cache of size 472 The buggy address is located 304 bytes inside of 472-byte region [ffff8801b36a7040, ffff8801b36a7218) The buggy address belongs to the page: page:ffffea0006cda9c0 count:1 mapcount:0 mapping:ffff8801b36a7040 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801b36a7040 0000000000000000 0000000100000006 raw: ffffea00066cfde0 ffffea000729bc20 ffff8801d9bec500 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801b36a7000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff8801b36a7080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801b36a7100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801b36a7180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801b36a7200: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================