From: Seth Forshee <sforshee@kernel.org>
To: Christian Brauner <brauner@kernel.org>
Cc: linux-fsdevel@vger.kernel.org, linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org
Subject: Re: [PATCH] xattr: restrict vfs_getxattr_alloc() allocation size
Date: Tue, 5 Mar 2024 08:33:57 -0600 [thread overview]
Message-ID: <ZectVeZtw/EmfAUA@do-x1extreme> (raw)
In-Reply-To: <20240305-effekt-luftzug-51913178f6cd@brauner>
On Tue, Mar 05, 2024 at 01:27:06PM +0100, Christian Brauner wrote:
> The vfs_getxattr_alloc() interface is a special-purpose in-kernel api
> that does a racy query-size+allocate-buffer+retrieve-data. It is used by
> EVM, IMA, and fscaps to retrieve xattrs. Recently, we've seen issues
> where 9p returned values that amount to allocating about 8000GB worth of
> memory (cf. [1]). That's now fixed in 9p. But vfs_getxattr_alloc() has
> no reason to allow getting xattr values that are larger than
> XATTR_MAX_SIZE as that's the limit we use for setting and getting xattr
> values and nothing currently goes beyond that limit afaict. Let it check
> for that and reject requests that are larger than that.
>
> Link: https://lore.kernel.org/r/ZeXcQmHWcYvfCR93@do-x1extreme [1]
> Signed-off-by: Christian Brauner <brauner@kernel.org>
Makes sense.
Reviewed-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
next prev parent reply other threads:[~2024-03-05 14:33 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-05 12:27 [PATCH] xattr: restrict vfs_getxattr_alloc() allocation size Christian Brauner
2024-03-05 13:59 ` Christoph Hellwig
2024-03-05 14:33 ` Seth Forshee [this message]
2024-03-05 15:17 ` Serge E. Hallyn
2024-03-05 16:21 ` Christian Brauner
2024-03-07 20:01 ` Jarkko Sakkinen
2024-03-07 20:03 ` Jarkko Sakkinen
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