1. 31 Mar, 2018 1 commit
    • Soheil Hassas Yeganeh's avatar
      tcp: reset sk_send_head in tcp_write_queue_purge · dbbf2d1e
      Soheil Hassas Yeganeh authored
      
      tcp_write_queue_purge clears all the SKBs in the write queue
      but does not reset the sk_send_head. As a result, we can have
      a NULL pointer dereference anywhere that we use tcp_send_head
      instead of the tcp_write_queue_tail.
      
      For example, after a27fd7a8 (tcp: purge write queue upon RST),
      we can purge the write queue on RST. Prior to
      75c119af (tcp: implement rb-tree based retransmit queue),
      tcp_push will only check tcp_send_head and then accesses
      tcp_write_queue_tail to send the actual SKB. As a result, it will
      dereference a NULL pointer.
      
      This has been reported twice for 4.14 where we don't have
      75c119af:
      
      By Timofey Titovets:
      
      [  422.081094] BUG: unable to handle kernel NULL pointer dereference
      at 0000000000000038
      [  422.081254] IP: tcp_push+0x42/0x110
      [  422.081314] PGD 0 P4D 0
      [  422.081364] Oops: 0002 [#1] SMP PTI
      
      By Yongjian Xu:
      
      BUG: unable to handle kernel NULL pointer dereference at 0000000000000038
      IP: tcp_push+0x48/0x120
      PGD 80000007ff77b067 P4D 80000007ff77b067 PUD 7fd989067 PMD 0
      Oops: 0002 [#18] SMP PTI
      Modules linked in: tcp_diag inet_diag tcp_bbr sch_fq iTCO_wdt
      iTCO_vendor_support pcspkr ixgbe mdio i2c_i801 lpc_ich joydev input_leds shpchp
      e1000e igb dca ptp pps_core hwmon mei_me mei ipmi_si ipmi_msghandler sg ses
      scsi_transport_sas enclosure ext4 jbd2 mbcache sd_mod ahci libahci megaraid_sas
      wmi ast ttm dm_mirror dm_region_hash dm_log dm_mod dax
      CPU: 6 PID: 14156 Comm: [ET_NET 6] Tainted: G D 4.14.26-1.el6.x86_64 #1
      Hardware name: LENOVO ThinkServer RD440 /ThinkServer RD440, BIOS A0TS80A
      09/22/2014
      task: ffff8807d78d8140 task.stack: ffffc9000e944000
      RIP: 0010:tcp_push+0x48/0x120
      RSP: 0018:ffffc9000e947a88 EFLAGS: 00010246
      RAX: 00000000000005b4 RBX: ffff880f7cce9c00 RCX: 0000000000000000
      RDX: 0000000000000000 RSI: 0000000000000040 RDI: ffff8807d00f5000
      RBP: ffffc9000e947aa8 R08: 0000000000001c84 R09: 0000000000000000
      R10: ffff8807d00f5158 R11: 0000000000000000 R12: ffff8807d00f5000
      R13: 0000000000000020 R14: 00000000000256d4 R15: 0000000000000000
      FS: 00007f5916de9700(0000) GS:ffff88107fd00000(0000) knlGS:0000000000000000
      CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      CR2: 0000000000000038 CR3: 00000007f8226004 CR4: 00000000001606e0
      Call Trace:
      tcp_sendmsg_locked+0x33d/0xe50
      tcp_sendmsg+0x37/0x60
      inet_sendmsg+0x39/0xc0
      sock_sendmsg+0x49/0x60
      sock_write_iter+0xb6/0x100
      do_iter_readv_writev+0xec/0x130
      ? rw_verify_area+0x49/0xb0
      do_iter_write+0x97/0xd0
      vfs_writev+0x7e/0xe0
      ? __wake_up_common_lock+0x80/0xa0
      ? __fget_light+0x2c/0x70
      ? __do_page_fault+0x1e7/0x530
      do_writev+0x60/0xf0
      ? inet_shutdown+0xac/0x110
      SyS_writev+0x10/0x20
      do_syscall_64+0x6f/0x140
      ? prepare_exit_to_usermode+0x8b/0xa0
      entry_SYSCALL_64_after_hwframe+0x3d/0xa2
      RIP: 0033:0x3135ce0c57
      RSP: 002b:00007f5916de4b00 EFLAGS: 00000293 ORIG_RAX: 0000000000000014
      RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000003135ce0c57
      RDX: 0000000000000002 RSI: 00007f5916de4b90 RDI: 000000000000606f
      RBP: 0000000000000000 R08: 0000000000000000 R09: 00007f5916de8c38
      R10: 0000000000000000 R11: 0000000000000293 R12: 00000000000464cc
      R13: 00007f5916de8c30 R14: 00007f58d8bef080 R15: 0000000000000002
      Code: 48 8b 97 60 01 00 00 4c 8d 97 58 01 00 00 41 b9 00 00 00 00 41 89 f3 4c 39
      d2 49 0f 44 d1 41 81 e3 00 80 00 00 0f 85 b0 00 00 00 <80> 4a 38 08 44 8b 8f 74
      06 00 00 44 89 8f 7c 06 00 00 83 e6 01
      RIP: tcp_push+0x48/0x120 RSP: ffffc9000e947a88
      CR2: 0000000000000038
      ---[ end trace 8d545c2e93515549 ]---
      
      Fixes: a27fd7a8 (tcp: purge write queue upon RST)
      Reported-by: default avatarTimofey Titovets <nefelim4ag@gmail.com>
      Reported-by: default avatarYongjian Xu <yongjianchn@gmail.com>
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
      Tested-by: default avatarYongjian Xu <yongjianchn@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      dbbf2d1e
  2. 28 Mar, 2018 39 commits