From: Eric Biggers <ebiggers@kernel.org>
To: wenyang.linux@foxmail.com
Cc: Christian Brauner <brauner@kernel.org>,
Jens Axboe <axboe@kernel.dk>,
Alexander Viro <viro@zeniv.linux.org.uk>, Jan Kara <jack@suse.cz>,
David Woodhouse <dwmw@amazon.co.uk>,
Matthew Wilcox <willy@infradead.org>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] eventfd: strictly check the count parameter of eventfd_write to avoid inputting illegal strings
Date: Wed, 7 Feb 2024 20:33:54 -0800 [thread overview]
Message-ID: <20240208043354.GA85799@sol.localdomain> (raw)
In-Reply-To: <tencent_10AAA44731FFFA493F9F5501521F07DD4D0A@qq.com>
On Wed, Feb 07, 2024 at 12:35:18AM +0800, wenyang.linux@foxmail.com wrote:
> By checking whether count is equal to sizeof(ucnt), such errors
> could be detected. It also follows the requirements of the manual.
Does it? This is what the eventfd manual page says:
A write(2) fails with the error EINVAL if the size of the supplied buffer
is less than 8 bytes, or if an attempt is made to write the value
0xffffffffffffffff.
So, *technically* it doesn't mention the behavior if the size is greater than 8
bytes. But one might assume that such writes are accepted, since otherwise it
would have been mentioned that they're rejected, just like writes < 8 bytes.
If the validation is indeed going to be made more strict, the manual page will
need to be fixed alongside it.
- Eric
next prev parent reply other threads:[~2024-02-08 4:33 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-06 16:35 [PATCH] eventfd: strictly check the count parameter of eventfd_write to avoid inputting illegal strings wenyang.linux
2024-02-07 9:56 ` Christian Brauner
2024-02-07 9:58 ` Christian Brauner
2024-02-08 4:33 ` Eric Biggers [this message]
2024-02-08 5:34 ` Wen Yang
2024-02-09 10:18 ` Christian Brauner
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