• Eric Dumazet's avatar
    net: remove hlist_nulls_add_tail_rcu() · d7efc6c1
    Eric Dumazet authored
    Alexander Potapenko reported use of uninitialized memory [1]
    
    This happens when inserting a request socket into TCP ehash,
    in __sk_nulls_add_node_rcu(), since sk_reuseport is not initialized.
    
    Bug was added by commit d894ba18 ("soreuseport: fix ordering for
    mixed v4/v6 sockets")
    
    Note that d296ba60 ("soreuseport: Resolve merge conflict for v4/v6
    ordering fix") missed the opportunity to get rid of
    hlist_nulls_add_tail_rcu() :
    
    Both UDP sockets and TCP/DCCP listeners no longer use
    __sk_nulls_add_node_rcu() for their hash insertion.
    
    Since all other sockets have unique 4-tuple, the reuseport status
    has no special meaning, so we can always use hlist_nulls_add_head_rcu()
    for them and save few cycles/instructions.
    
    [1]
    
    ==================================================================
    BUG: KMSAN: use of uninitialized memory in inet_ehash_insert+0xd40/0x1050
    CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.13.0+ #3288
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    Call Trace:
     <IRQ>
     __dump_stack lib/dump_stack.c:16
     dump_stack+0x185/0x1d0 lib/dump_stack.c:52
     kmsan_report+0x13f/0x1c0 mm/kmsan/kmsan.c:1016
     __msan_warning_32+0x69/0xb0 mm/kmsan/kmsan_instr.c:766
     __sk_nulls_add_node_rcu ./include/net/sock.h:684
     inet_ehash_insert+0xd40/0x1050 net/ipv4/inet_hashtables.c:413
     reqsk_queue_hash_req net/ipv4/inet_connection_sock.c:754
     inet_csk_reqsk_queue_hash_add+0x1cc/0x300 net/ipv4/inet_connection_sock.c:765
     tcp_conn_request+0x31e7/0x36f0 net/ipv4/tcp_input.c:6414
     tcp_v4_conn_request+0x16d/0x220 net/ipv4/tcp_ipv4.c:1314
     tcp_rcv_state_process+0x42a/0x7210 net/ipv4/tcp_input.c:5917
     tcp_v4_do_rcv+0xa6a/0xcd0 net/ipv4/tcp_ipv4.c:1483
     tcp_v4_rcv+0x3de0/0x4ab0 net/ipv4/tcp_ipv4.c:1763
     ip_local_deliver_finish+0x6bb/0xcb0 net/ipv4/ip_input.c:216
     NF_HOOK ./include/linux/netfilter.h:248
     ip_local_deliver+0x3fa/0x480 net/ipv4/ip_input.c:257
     dst_input ./include/net/dst.h:477
     ip_rcv_finish+0x6fb/0x1540 net/ipv4/ip_input.c:397
     NF_HOOK ./include/linux/netfilter.h:248
     ip_rcv+0x10f6/0x15c0 net/ipv4/ip_input.c:488
     __netif_receive_skb_core+0x36f6/0x3f60 net/core/dev.c:4298
     __netif_receive_skb net/core/dev.c:4336
     netif_receive_skb_internal+0x63c/0x19c0 net/core/dev.c:4497
     napi_skb_finish net/core/dev.c:4858
     napi_gro_receive+0x629/0xa50 net/core/dev.c:4889
     e1000_receive_skb drivers/net/ethernet/intel/e1000/e1000_main.c:4018
     e1000_clean_rx_irq+0x1492/0x1d30
    drivers/net/ethernet/intel/e1000/e1000_main.c:4474
     e1000_clean+0x43aa/0x5970 drivers/net/ethernet/intel/e1000/e1000_main.c:3819
     napi_poll net/core/dev.c:5500
     net_rx_action+0x73c/0x1820 net/core/dev.c:5566
     __do_softirq+0x4b4/0x8dd kernel/softirq.c:284
     invoke_softirq kernel/softirq.c:364
     irq_exit+0x203/0x240 kernel/softirq.c:405
     exiting_irq+0xe/0x10 ./arch/x86/include/asm/apic.h:638
     do_IRQ+0x15e/0x1a0 arch/x86/kernel/irq.c:263
     common_interrupt+0x86/0x86
    
    Fixes: d894ba18 ("soreuseport: fix ordering for mixed v4/v6 sockets")
    Fixes: d296ba60
    
     ("soreuseport: Resolve merge conflict for v4/v6 ordering fix")
    Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
    Reported-by: default avatarAlexander Potapenko <glider@google.com>
    Acked-by: default avatarCraig Gallek <kraig@google.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    d7efc6c1