[bug-inetutils] telnetd bug: Busy loop in io_drain can be abused for DOS attack

[Petr Malát]

Hello again,
I found a problem in telnet demon in a function, which waits for reply
from client. The problem is that it calls read() on non-blocking
filedescriptor in a loop, until some data comes. If the client is evil
and does not send a reply, but keeps the connection open, then server
is calling read() again and again consuming CPU time. The problem can
be solved by calling select() before reading from filedescriptor.
Patch is attached.
  Petr

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io_drain.patch
Description: Binary data