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From: Jann Horn <jannh@google.com>
To: Pavel Begunkov <asml.silence@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>, io-uring <io-uring@vger.kernel.org>
Subject: Re: [PATCH 5/5] io_uring: fix use after free
Date: Fri, 3 Jul 2020 04:39:48 +0200	[thread overview]
Message-ID: <CAG48ez2yJdH3W_PHzvEuwpORB6MoTf9M5nOm1JL3H-wAnkJBBA@mail.gmail.com> (raw)
In-Reply-To: <1221be71ac8977607748d381f90439af4781c1e5.1593424923.git.asml.silence@gmail.com>

On Mon, Jun 29, 2020 at 10:44 PM Pavel Begunkov <asml.silence@gmail.com> wrote:
> After __io_free_req() put a ctx ref, it should assumed that the ctx may
> already be gone. However, it can be accessed to put back fallback req.
> Free req first and then put a req.

Please stick "Fixes" tags on bug fixes to make it easy to see when the
fixed bug was introduced (especially for ones that fix severe issues
like UAFs). From a cursory glance, it kinda seems like this one
_might_ have been introduced in 2b85edfc0c90ef, which would mean that
it landed in 5.6? But I can't really tell for sure without investing
more time; you probably know that better.

And if this actually does affect existing releases, please also stick
a "Cc: stable@vger.kernel.org" tag on it so that the fix can be
shipped to users of those releases.

  reply	other threads:[~2020-07-03  2:40 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-29 10:12 [PATCH 0/5] cleanup for req_free/find_next Pavel Begunkov
2020-06-29 10:12 ` [PATCH 1/5] io_uring: deduplicate freeing linked timeouts Pavel Begunkov
2020-06-29 10:13 ` [PATCH 2/5] io_uring: replace find_next() out param with ret Pavel Begunkov
2020-06-29 10:13 ` [PATCH 3/5] io_uring: kill REQ_F_TIMEOUT Pavel Begunkov
2020-06-29 10:13 ` [PATCH 4/5] io_uring: kill REQ_F_TIMEOUT_NOSEQ Pavel Begunkov
2020-06-29 10:13 ` [PATCH 5/5] io_uring: fix use after free Pavel Begunkov
2020-07-03  2:39   ` Jann Horn [this message]
2020-07-03 19:48     ` Pavel Begunkov
2020-07-03 21:32       ` Jann Horn
2020-07-04  6:49         ` Pavel Begunkov
2020-07-07 12:46           ` Pavel Begunkov
2020-07-07 13:56             ` Jens Axboe

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