Eric Dumazet 8ba6092471 tcp: fastopen: tcp_connect() must refresh the route
With new TCP_FASTOPEN_CONNECT socket option, there is a possibility
to call tcp_connect() while socket sk_dst_cache is either NULL
or invalid.

 +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 4
 +0 fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0
 +0 setsockopt(4, SOL_TCP, TCP_FASTOPEN_CONNECT, [1], 4) = 0
 +0 connect(4, ..., ...) = 0

<< sk->sk_dst_cache becomes obsolete, or even set to NULL >>

 +1 sendto(4, ..., 1000, MSG_FASTOPEN, ..., ...) = 1000

We need to refresh the route otherwise bad things can happen,
especially when syzkaller is running on the host :/

Fixes: 19f6d3f3c8422 ("net/tcp-fastopen: Add new API support")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Wei Wang <weiwan@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Acked-by: Wei Wang <weiwan@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-08 20:39:52 -07:00
2017-08-04 11:23:58 -07:00
2017-07-28 14:44:56 -07:00
2017-07-28 17:21:41 -07:00
2017-07-27 10:44:28 -07:00
2017-07-30 12:40:36 -07:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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