87b34cd648
[ Upstream commit 8a0ed250f911da31a2aef52101bc707846a800ff ] The GRE tunnel device can pull existing outer headers in ipge_xmit. This is a rare path, apparently unique to this device. The below commit ensured that pulling does not move skb->data beyond csum_start. But it has a false positive if ip_summed is not CHECKSUM_PARTIAL and thus csum_start is irrelevant. Refine to exclude this. At the same time simplify and strengthen the test. Simplify, by moving the check next to the offending pull, making it more self documenting and removing an unnecessary branch from other code paths. Strengthen, by also ensuring that the transport header is correct and therefore the inner headers will be after skb_reset_inner_headers. The transport header is set to csum_start in skb_partial_csum_set. Link: https://lore.kernel.org/netdev/YS+h%2FtqCJJiQei+W@shredder/ Fixes: 1d011c4803c7 ("ip_gre: add validation for csum_start") Reported-by: Ido Schimmel <idosch@idosch.org> Suggested-by: Alexander Duyck <alexander.duyck@gmail.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Alexander Duyck <alexanderduyck@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.