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Sabrina Dubroca c7272c2f12 net: ipv4: don't allow setting net.ipv4.route.min_pmtu below 68
According to RFC 1191 sections 3 and 4, ICMP frag-needed messages
indicating an MTU below 68 should be rejected:

    A host MUST never reduce its estimate of the Path MTU below 68
    octets.

and (talking about ICMP frag-needed's Next-Hop MTU field):

    This field will never contain a value less than 68, since every
    router "must be able to forward a datagram of 68 octets without
    fragmentation".

Furthermore, by letting net.ipv4.route.min_pmtu be set to negative
values, we can end up with a very large PMTU when (-1) is cast into u32.

Let's also make ip_rt_min_pmtu a u32, since it's only ever compared to
unsigned ints.

Reported-by: Jianlin Shi <jishi@redhat.com>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-27 11:13:36 -05:00
arch ARM: orion5x: Revert commit 4904dbda41. 2018-02-26 13:41:47 -05:00
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Documentation DT: net: renesas,ravb: document R8A77980 bindings 2018-02-26 15:10:31 -05:00
drivers Merge branch 'for-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth 2018-02-27 10:54:37 -05:00
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fs Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-02-22 17:04:06 -08:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-02-23 15:14:17 -08:00
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kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-02-23 15:14:17 -08:00
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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.