Re: [PATCH 4.4.y] tcp: Fix missing range_truesize enlargement in the backport

From: Takashi Iwai
Date: Wed Aug 15 2018 - 08:15:14 EST

On Wed, 15 Aug 2018 13:11:21 +0200,
Greg Kroah-Hartman wrote:
> On Wed, Aug 15, 2018 at 11:58:46AM +0200, Takashi Iwai wrote:
> > The 4.4.y stable backport dc6ae4dffd65 for the upstream commit
> > 3d4bf93ac120 ("tcp: detect malicious patterns in
> > tcp_collapse_ofo_queue()") missed a line that enlarges the
> > range_truesize value, which broke the whole check.
> >
> > Fixes: dc6ae4dffd65 ("tcp: detect malicious patterns in tcp_collapse_ofo_queue()")
> > Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
> > ---
> >
> > Greg, this is a fix-up specific to 4.4.y stable backport that had a
> > slightly different form from upstream fix. I haven't looked at the
> > older trees, but 4.9.y and later took the upstream fix as is, so this
> > patch isn't needed for them.
> >
> > The patch hasn't been tested with the real test case, though; let me
> > know if the current code is intended. Thanks!
> Hm, I did the initial backport, and then Eric showed what I got wrong
> and fixed that up, so being still wrong is not inconceivable at all :)
> Have you tried testing this with the reproducer? That might be the best
> verification here. If your testing proves to be good, I'll gladly take
> this patch, thanks!

No, I haven't tested it, just followed from the thread in the past
(and hope that our QA team will test that sooner or later :)
Will let you know if we find any issues in the current tree.

And, if the current code works as intended, it's great, of course.