From: Kees Cook <kees@kernel.org>
To: nicolas.bouchinet@clip-os.org
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Nicolas Bouchinet <nicolas.bouchinet@ssi.gouv.fr>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jirislaby@kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
Luis Chamberlain <mcgrof@kernel.org>,
Joel Granados <j.granados@samsung.com>,
Andrew Morton <akpm@linux-foundation.org>,
Neil Horman <nhorman@tuxdriver.com>, Lin Feng <linf@wangsu.com>,
Theodore Ts'o <tytso@mit.edu>
Subject: Re: [PATCH v4 2/2] sysctl: Fix underflow value setting risk in vm_table
Date: Wed, 15 Jan 2025 16:32:33 -0800 [thread overview]
Message-ID: <202501151632.9FF3FF0@keescook> (raw)
In-Reply-To: <20250115132211.25400-3-nicolas.bouchinet@clip-os.org>
On Wed, Jan 15, 2025 at 02:22:09PM +0100, nicolas.bouchinet@clip-os.org wrote:
> From: Nicolas Bouchinet <nicolas.bouchinet@ssi.gouv.fr>
>
> Commit 3b3376f222e3 ("sysctl.c: fix underflow value setting risk in vm_table")
> fixes underflow value setting risk in vm_table but misses vdso_enabled
> sysctl.
>
> vdso_enabled sysctl is initialized with .extra1 value as SYSCTL_ZERO to
> avoid negative value writes but the proc_handler is proc_dointvec and
> not proc_dointvec_minmax and thus do not uses .extra1 and .extra2.
>
> The following command thus works :
>
> `# echo -1 > /proc/sys/vm/vdso_enabled`
>
> This patch properly sets the proc_handler to proc_dointvec_minmax.
> In addition to .extra1, .extra2 is set to SYSCTL_ONE. The sysctl is
> thus bounded between 0 and 1.
>
> Fixes: 3b3376f222e3 ("sysctl.c: fix underflow value setting risk in vm_table")
> Signed-off-by: Nicolas Bouchinet <nicolas.bouchinet@ssi.gouv.fr>
Reviewed-by: Kees Cook <kees@kernel.org>
--
Kees Cook
next prev parent reply other threads:[~2025-01-16 0:32 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-15 13:22 [PATCH v4 0/2] Fixes multiple sysctl proc_handler usage error nicolas.bouchinet
2025-01-15 13:22 ` [PATCH v4 1/2] coredump: Fixes core_pipe_limit sysctl proc_handler nicolas.bouchinet
2025-01-16 0:32 ` Kees Cook
2025-01-17 10:55 ` Nicolas Bouchinet
2025-01-15 13:22 ` [PATCH v4 2/2] sysctl: Fix underflow value setting risk in vm_table nicolas.bouchinet
2025-01-16 0:32 ` Kees Cook [this message]
2025-02-17 10:35 ` [PATCH v4 0/2] Fixes multiple sysctl proc_handler usage error Joel Granados
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