Exposed sshd -- looping sshd-auth

[Theo de Raadt]

  9980      1 sshd-auth poll(0x7f7fffffe4b0, 0x1, 0xffffffff) = 1
  9980      1 sshd-auth read(0x5, 0x7f7fffffe53f, 0x1) Err#35 EAGAIN

- poll with 1 descriptor, which is only checking POLLIN 

- returns 1, that means the kernel says this socket can read at
  least one byte (sucessfully), or detect EOF from reading 0

- but the subsequent read() returns EAGAIN/EWOUDBLOCK

The kernel does not seem to be following the contract correctly.