• Alexander Potapenko's avatar
    ipv4: ipv6: initialize treq->txhash in cookie_v[46]_check() · d0724741
    Alexander Potapenko authored
    
    [ Upstream commit 18bcf290 ]
    
    KMSAN reported use of uninitialized memory in skb_set_hash_from_sk(),
    which originated from the TCP request socket created in
    cookie_v6_check():
    
     ==================================================================
     BUG: KMSAN: use of uninitialized memory in tcp_transmit_skb+0xf77/0x3ec0
     CPU: 1 PID: 2949 Comm: syz-execprog Not tainted 4.11.0-rc5+ #2931
     Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
     TCP: request_sock_TCPv6: Possible SYN flooding on port 20028. Sending cookies.  Check SNMP counters.
     Call Trace:
      <IRQ>
      __dump_stack lib/dump_stack.c:16
      dump_stack+0x172/0x1c0 lib/dump_stack.c:52
      kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:927
      __msan_warning_32+0x61/0xb0 mm/kmsan/kmsan_instr.c:469
      skb_set_hash_from_sk ./include/net/sock.h:2011
      tcp_transmit_skb+0xf77/0x3ec0 net/ipv4/tcp_output.c:983
      tcp_send_ack+0x75b/0x830 net/ipv4/tcp_output.c:3493
      tcp_delack_timer_handler+0x9a6/0xb90 net/ipv4/tcp_timer.c:284
      tcp_delack_timer+0x1b0/0x310 net/ipv4/tcp_timer.c:309
      call_timer_fn+0x240/0x520 kernel/time/timer.c:1268
      expire_timers kernel/time/timer.c:1307
      __run_timers+0xc13/0xf10 kernel/time/timer.c:1601
      run_timer_softirq+0x36/0xa0 kernel/time/timer.c:1614
      __do_softirq+0x485/0x942 kernel/softirq.c:284
      invoke_softirq kernel/softirq.c:364
      irq_exit+0x1fa/0x230 kernel/softirq.c:405
      exiting_irq+0xe/0x10 ./arch/x86/include/asm/apic.h:657
      smp_apic_timer_interrupt+0x5a/0x80 arch/x86/kernel/apic/apic.c:966
      apic_timer_interrupt+0x86/0x90 arch/x86/entry/entry_64.S:489
     RIP: 0010:native_restore_fl ./arch/x86/include/asm/irqflags.h:36
     RIP: 0010:arch_local_irq_restore ./arch/x86/include/asm/irqflags.h:77
     RIP: 0010:__msan_poison_alloca+0xed/0x120 mm/kmsan/kmsan_instr.c:440
     RSP: 0018:ffff880024917cd8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff10
     RAX: 0000000000000246 RBX: ffff8800224c0000 RCX: 0000000000000005
     RDX: 0000000000000004 RSI: ffff880000000000 RDI: ffffea0000b6d770
     RBP: ffff880024917d58 R08: 0000000000000dd8 R09: 0000000000000004
     R10: 0000160000000000 R11: 0000000000000000 R12: ffffffff85abf810
     R13: ffff880024917dd8 R14: 0000000000000010 R15: ffffffff81cabde4
      </IRQ>
      poll_select_copy_remaining+0xac/0x6b0 fs/select.c:293
      SYSC_select+0x4b4/0x4e0 fs/select.c:653
      SyS_select+0x76/0xa0 fs/select.c:634
      entry_SYSCALL_64_fastpath+0x13/0x94 arch/x86/entry/entry_64.S:204
     RIP: 0033:0x4597e7
     RSP: 002b:000000c420037ee0 EFLAGS: 00000246 ORIG_RAX: 0000000000000017
     RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004597e7
     RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
     RBP: 000000c420037ef0 R08: 000000c420037ee0 R09: 0000000000000059
     R10: 0000000000000000 R11: 0000000000000246 R12: 000000000042dc20
     R13: 00000000000000f3 R14: 0000000000000030 R15: 0000000000000003
     chained origin:
      save_stack_trace+0x37/0x40 arch/x86/kernel/stacktrace.c:59
      kmsan_save_stack_with_flags mm/kmsan/kmsan.c:302
      kmsan_save_stack mm/kmsan/kmsan.c:317
      kmsan_internal_chain_origin+0x12a/0x1f0 mm/kmsan/kmsan.c:547
      __msan_store_shadow_origin_4+0xac/0x110 mm/kmsan/kmsan_instr.c:259
      tcp_create_openreq_child+0x709/0x1ae0 net/ipv4/tcp_minisocks.c:472
      tcp_v6_syn_recv_sock+0x7eb/0x2a30 net/ipv6/tcp_ipv6.c:1103
      tcp_get_cookie_sock+0x136/0x5f0 net/ipv4/syncookies.c:212
      cookie_v6_check+0x17a9/0x1b50 net/ipv6/syncookies.c:245
      tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:989
      tcp_v6_do_rcv+0xdd8/0x1c60 net/ipv6/tcp_ipv6.c:1298
      tcp_v6_rcv+0x41a3/0x4f00 net/ipv6/tcp_ipv6.c:1487
      ip6_input_finish+0x82f/0x1ee0 net/ipv6/ip6_input.c:279
      NF_HOOK ./include/linux/netfilter.h:257
      ip6_input+0x239/0x290 net/ipv6/ip6_input.c:322
      dst_input ./include/net/dst.h:492
      ip6_rcv_finish net/ipv6/ip6_input.c:69
      NF_HOOK ./include/linux/netfilter.h:257
      ipv6_rcv+0x1dbd/0x22e0 net/ipv6/ip6_input.c:203
      __netif_receive_skb_core+0x2f6f/0x3a20 net/core/dev.c:4208
      __netif_receive_skb net/core/dev.c:4246
      process_backlog+0x667/0xba0 net/core/dev.c:4866
      napi_poll net/core/dev.c:5268
      net_rx_action+0xc95/0x1590 net/core/dev.c:5333
      __do_softirq+0x485/0x942 kernel/softirq.c:284
     origin:
      save_stack_trace+0x37/0x40 arch/x86/kernel/stacktrace.c:59
      kmsan_save_stack_with_flags mm/kmsan/kmsan.c:302
      kmsan_internal_poison_shadow+0xb1/0x1a0 mm/kmsan/kmsan.c:198
      kmsan_kmalloc+0x7f/0xe0 mm/kmsan/kmsan.c:337
      kmem_cache_alloc+0x1c2/0x1e0 mm/slub.c:2766
      reqsk_alloc ./include/net/request_sock.h:87
      inet_reqsk_alloc+0xa4/0x5b0 net/ipv4/tcp_input.c:6200
      cookie_v6_check+0x4f4/0x1b50 net/ipv6/syncookies.c:169
      tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:989
      tcp_v6_do_rcv+0xdd8/0x1c60 net/ipv6/tcp_ipv6.c:1298
      tcp_v6_rcv+0x41a3/0x4f00 net/ipv6/tcp_ipv6.c:1487
      ip6_input_finish+0x82f/0x1ee0 net/ipv6/ip6_input.c:279
      NF_HOOK ./include/linux/netfilter.h:257
      ip6_input+0x239/0x290 net/ipv6/ip6_input.c:322
      dst_input ./include/net/dst.h:492
      ip6_rcv_finish net/ipv6/ip6_input.c:69
      NF_HOOK ./include/linux/netfilter.h:257
      ipv6_rcv+0x1dbd/0x22e0 net/ipv6/ip6_input.c:203
      __netif_receive_skb_core+0x2f6f/0x3a20 net/core/dev.c:4208
      __netif_receive_skb net/core/dev.c:4246
      process_backlog+0x667/0xba0 net/core/dev.c:4866
      napi_poll net/core/dev.c:5268
      net_rx_action+0xc95/0x1590 net/core/dev.c:5333
      __do_softirq+0x485/0x942 kernel/softirq.c:284
     ==================================================================
    
    Similar error is reported for cookie_v4_check().
    
    Fixes: 58d607d3 ("tcp: provide skb->hash to synack packets")
    Signed-off-by: default avatarAlexander Potapenko <glider@google.com>
    Acked-by: default avatarEric Dumazet <edumazet@google.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    d0724741
syncookies.c 7.24 KB