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From: Willy Tarreau <w@1wt.eu>
To: Eric Biggers <ebiggers3@gmail.com>
Cc: linux-fsdevel@vger.kernel.org,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Joe Lawrence <joe.lawrence@redhat.com>,
	Michael Kerrisk <mtk.manpages@gmail.com>,
	Mikulas Patocka <mpatocka@redhat.com>,
	"Luis R . Rodriguez" <mcgrof@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	linux-kernel@vger.kernel.org, Eric Biggers <ebiggers@google.com>
Subject: Re: [PATCH 4/7] pipe: fix off-by-one error when checking buffer limits
Date: Mon, 8 Jan 2018 07:42:00 +0100	[thread overview]
Message-ID: <20180108064200.GB10411@1wt.eu> (raw)
In-Reply-To: <20180108053542.6472-5-ebiggers3@gmail.com>

On Sun, Jan 07, 2018 at 09:35:39PM -0800, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> With pipe-user-pages-hard set to 'N', users were actually only allowed
> up to 'N - 1' buffers; and likewise for pipe-user-pages-soft.
> 
> Fix this to allow up to 'N' buffers, as would be expected.

Interesting. I was a bit surprized at first and found that this was
changed by b0b91d1 ("pipe: fix limit checking in pipe_set_size()").
Prior to this fix, only already allocated pipes were counted. After
the fix, an allocation attempt was made before checking the size. So
I think that your fix is needed in stable versions which backported
the commit above.

> Signed-off-by: Eric Biggers <ebiggers@google.com>

Acked-by: Willy Tarreau <w@1wt.eu>

Thanks,
Willy

  reply	other threads:[~2018-01-08  6:42 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-08  5:35 [PATCH 0/7] pipe: buffer limits fixes and cleanups Eric Biggers
2018-01-08  5:35 ` [PATCH 1/7] pipe, sysctl: drop 'min' parameter from pipe-max-size converter Eric Biggers
2018-01-09 22:20   ` Kees Cook
2018-01-10  2:29     ` Eric Biggers
2018-01-10 17:30       ` Kees Cook
2018-01-08  5:35 ` [PATCH 2/7] pipe, sysctl: remove pipe_proc_fn() Eric Biggers
2018-01-08  5:35 ` [PATCH 3/7] pipe: actually allow root to exceed the pipe buffer limits Eric Biggers
2018-01-09 22:23   ` Kees Cook
2018-01-10  2:34     ` Eric Biggers
2018-01-08  5:35 ` [PATCH 4/7] pipe: fix off-by-one error when checking " Eric Biggers
2018-01-08  6:42   ` Willy Tarreau [this message]
2018-01-08  5:35 ` [PATCH 5/7] pipe: reject F_SETPIPE_SZ with size over UINT_MAX Eric Biggers
2018-01-09 22:24   ` Kees Cook
2018-01-08  5:35 ` [PATCH 6/7] pipe: simplify round_pipe_size() Eric Biggers
2018-01-09 22:27   ` Kees Cook
2018-01-10  2:52     ` Eric Biggers
2018-01-10  3:13       ` Kees Cook
2018-01-08  5:35 ` [PATCH 7/7] pipe: read buffer limits atomically Eric Biggers
2018-01-09 22:27   ` Kees Cook

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