1. 18 Feb, 2017 1 commit
    • Eric Dumazet's avatar
      can: Fix kernel panic at security_sock_rcv_skb · adf86d59
      Eric Dumazet authored
      [ Upstream commit f1712c73 ]
      
      Zhang Yanmin reported crashes [1] and provided a patch adding a
      synchronize_rcu() call in can_rx_unregister()
      
      The main problem seems that the sockets themselves are not RCU
      protected.
      
      If CAN uses RCU for delivery, then sockets should be freed only after
      one RCU grace period.
      
      Recent kernels could use sock_set_flag(sk, SOCK_RCU_FREE), but let's
      ease stable backports with the following fix instead.
      
      [1]
      BUG: unable to handle kernel NULL pointer dereference at (null)
      IP: [<ffffffff81495e25>] selinux_socket_sock_rcv_skb+0x65/0x2a0
      
      Call Trace:
       <IRQ>
       [<ffffffff81485d8c>] security_sock_rcv_skb+0x4c/0x60
       [<ffffffff81d55771>] sk_filter+0x41/0x210
       [<ffffffff81d12913>] sock_queue_rcv_skb+0x53/0x3a0
       [<ffffffff81f0a2b3>] raw_rcv+0x2a3/0x3c0
       [<ffffffff81f06eab>] can_rcv_filter+0x12b/0x370
       [<ffffffff81f07af9>] can_receive+0xd9/0x120
       [<ffffffff81f07beb>] can_rcv+0xab/0x100
       [<ffffffff81d362ac>] __netif_receive_skb_core+0xd8c/0x11f0
       [<ffffffff81d36734>] __netif_receive_skb+0x24/0xb0
       [<ffffffff81d37f67>] process_backlog+0x127/0x280
       [<ffffffff81d36f7b>] net_rx_action+0x33b/0x4f0
       [<ffffffff810c88d4>] __do_softirq+0x184/0x440
       [<ffffffff81f9e86c>] do_softirq_own_stack+0x1c/0x30
       <EOI>
       [<ffffffff810c76fb>] do_softirq.part.18+0x3b/0x40
       [<ffffffff810c8bed>] do_softirq+0x1d/0x20
       [<ffffffff81d30085>] netif_rx_ni+0xe5/0x110
       [<ffffffff8199cc87>] slcan_receive_buf+0x507/0x520
       [<ffffffff8167ef7c>] flush_to_ldisc+0x21c/0x230
       [<ffffffff810e3baf>] process_one_work+0x24f/0x670
       [<ffffffff810e44ed>] worker_thread+0x9d/0x6f0
       [<ffffffff810e4450>] ? rescuer_thread+0x480/0x480
       [<ffffffff810ebafc>] kthread+0x12c/0x150
       [<ffffffff81f9ccef>] ret_from_fork+0x3f/0x70
      Reported-by: default avatarZhang Yanmin <yanmin.zhang@intel.com>
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Acked-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      adf86d59
  2. 14 Feb, 2017 39 commits