TCP: request_sock_subflow: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. ================================================================== BUG: KASAN: slab-out-of-bounds in subflow_syn_recv_sock+0x945/0xd80 net/mptcp/subflow.c:447 Read of size 1 at addr ffff8880a1ba8f60 by task ksoftirqd/1/16 CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.8.0-rc4-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+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x436 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 subflow_syn_recv_sock+0x945/0xd80 net/mptcp/subflow.c:447 tcp_get_cookie_sock+0xca/0x510 net/ipv4/syncookies.c:209 cookie_v6_check+0x14f2/0x2250 net/ipv6/syncookies.c:255 tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1134 [inline] tcp_v6_do_rcv+0xf50/0x1290 net/ipv6/tcp_ipv6.c:1459 tcp_v6_rcv+0x312b/0x3470 net/ipv6/tcp_ipv6.c:1670 ip6_protocol_deliver_rcu+0x2e8/0x1670 net/ipv6/ip6_input.c:433 ip6_input_finish+0x7f/0x160 net/ipv6/ip6_input.c:474 NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:483 dst_input include/net/dst.h:449 [inline] ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ipv6_rcv+0x28e/0x3c0 net/ipv6/ip6_input.c:307 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5281 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5395 process_backlog+0x28d/0x7f0 net/core/dev.c:6239 napi_poll net/core/dev.c:6684 [inline] net_rx_action+0x4a1/0xe60 net/core/dev.c:6752 __do_softirq+0x34c/0xa60 kernel/softirq.c:292 run_ksoftirqd kernel/softirq.c:630 [inline] run_ksoftirqd+0x89/0x100 kernel/softirq.c:622 smpboot_thread_fn+0x655/0x9e0 kernel/smpboot.c:165 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Allocated by task 16: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494 slab_post_alloc_hook mm/slab.h:586 [inline] slab_alloc mm/slab.c:3320 [inline] kmem_cache_alloc+0x12c/0x3b0 mm/slab.c:3484 reqsk_alloc include/net/request_sock.h:84 [inline] inet_reqsk_alloc+0x91/0x710 net/ipv4/tcp_input.c:6516 cookie_v6_check+0x5a5/0x2250 net/ipv6/syncookies.c:173 tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1134 [inline] tcp_v6_do_rcv+0xf50/0x1290 net/ipv6/tcp_ipv6.c:1459 tcp_v6_rcv+0x312b/0x3470 net/ipv6/tcp_ipv6.c:1670 ip6_protocol_deliver_rcu+0x2e8/0x1670 net/ipv6/ip6_input.c:433 ip6_input_finish+0x7f/0x160 net/ipv6/ip6_input.c:474 NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:483 dst_input include/net/dst.h:449 [inline] ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ipv6_rcv+0x28e/0x3c0 net/ipv6/ip6_input.c:307 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5281 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5395 process_backlog+0x28d/0x7f0 net/core/dev.c:6239 napi_poll net/core/dev.c:6684 [inline] net_rx_action+0x4a1/0xe60 net/core/dev.c:6752 __do_softirq+0x34c/0xa60 kernel/softirq.c:292 Freed by task 0: (stack is not available) The buggy address belongs to the object at ffff8880a1ba8e10 which belongs to the cache request_sock_TCPv6 of size 336 The buggy address is located 0 bytes to the right of 336-byte region [ffff8880a1ba8e10, ffff8880a1ba8f60) The buggy address belongs to the page: page:ffffea000286ea00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880a1ba8ff6 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea0002986508 ffff8880a3eebf50 ffff8882157ffc40 raw: ffff8880a1ba8ff6 ffff8880a1ba8000 000000010000000a 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a1ba8e00: fc fc 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880a1ba8e80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8880a1ba8f00: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc ^ ffff8880a1ba8f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a1ba9000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================