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From: Alexey Gladkov <gladkov.alexey@gmail.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux Containers <containers@lists.linux.dev>
Subject: Re: [PATCH] ucounts: Fix UCOUNT_RLIMIT_SIGPENDING counter leak
Date: Thu, 8 Jul 2021 13:00:16 +0200	[thread overview]
Message-ID: <20210708110016.seeviageyspgctzk@example.org> (raw)
In-Reply-To: <CAHk-=wirhF8G1XniAfxzJXCYUnuAx23Q1WLi_n4+HGsUXv72KQ@mail.gmail.com>

On Wed, Jul 07, 2021 at 10:23:35AM -0700, Linus Torvalds wrote:
> On Wed, Jul 7, 2021 at 9:50 AM Alexey Gladkov <legion@kernel.org> wrote:
> >
> > >   +             dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING, 1);
> > >   +             fallthrough;
> > >   +     case LONG_MAX:
> >
> > I think that the counter should be decreased in this case too.
> > inc_rlimit_ucounts() increments the counter in all parent userns. If we
> > don't decrease the counter then the parent userns will have a counter
> > leak.
> 
> Ack. So basically that patch, but move the dec_rlimit_ucounts() into
> the LONG_MAX case?

Yep.

> Would you mind making a real patch with a commit message, and trying
> whatever test-case you had for that KASAN use-after-free report?

Sure. I will.

-- 
Rgrds, legion


  parent reply	other threads:[~2021-07-08 11:07 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-28 22:35 [GIT PULL] ucounts: Count rlimits in each user namespace Eric W. Biederman
2021-06-29  3:47 ` Linus Torvalds
2021-06-29 15:04   ` Eric W. Biederman
2021-06-29 15:51   ` Eric W. Biederman
2021-06-29 16:34     ` Linus Torvalds
2021-06-29 16:42       ` Eric W. Biederman
2021-06-29 17:09         ` Eric W. Biederman
2021-07-01 16:41           ` Alexey Gladkov
2021-07-01 20:05             ` Eric W. Biederman
2021-06-29 17:17   ` Alexey Gladkov
2021-06-29 18:07     ` Linus Torvalds
2021-06-29 20:20       ` Alexey Gladkov
2021-06-29 20:33         ` Linus Torvalds
2021-06-29 21:22           ` Alexey Gladkov
2021-07-02 17:54           ` [PATCH] ucounts: Fix UCOUNT_RLIMIT_SIGPENDING counter leak Alexey Gladkov
2021-07-02 22:13             ` Linus Torvalds
2021-07-07 16:50               ` Alexey Gladkov
2021-07-07 17:23                 ` Linus Torvalds
2021-07-08 10:33                   ` [PATCH v2] " Alexey Gladkov
2021-07-08 18:44                     ` Linus Torvalds
2021-07-08 11:00                   ` Alexey Gladkov [this message]
2021-06-29  3:50 ` [GIT PULL] ucounts: Count rlimits in each user namespace pr-tracker-bot

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