From: Andrew Morton <akpm@linux-foundation.org>
To: Waiman Long <longman@redhat.com>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>,
Kees Cook <keescook@chromium.org>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH 2/3] sysctl: Warn when a clamped sysctl parameter is set out of range
Date: Tue, 20 Feb 2018 15:17:05 -0800 [thread overview]
Message-ID: <20180220151705.8b4519f105db8f5c119015f0@linux-foundation.org> (raw)
In-Reply-To: <1519059231-2456-3-git-send-email-longman@redhat.com>
On Mon, 19 Feb 2018 11:53:50 -0500 Waiman Long <longman@redhat.com> wrote:
> Even with clamped sysctl parameters, it is still not that straight
> forward to figure out the exact range of those parameters. One may
> try to write extreme parameter values to see if they get clamped.
> To make it easier, a warning with the expected range will now be
> printed in the kernel ring buffer when a clamped sysctl parameter
> receives an out of range value.
This assumes that do_proc_dointvec_minmax_conv() and
do_proc_douintvec_minmax_conv() are only ever called by privileged
userspace. Because we mustn't give unprivileged applications a way to
spam the kernel logs.
That's presumably true in the case of the caller you just added, but I
don't see what we can do to guarantee this in the future, so perhaps we
should add some permission check to the pr_warn()?
next prev parent reply other threads:[~2018-02-20 23:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-19 16:53 [PATCH 0/3] ipc: Clamp msgmni and shmmni to the real IPC_MNI limit Waiman Long
2018-02-19 16:53 ` [PATCH 1/3] sysctl: Add range clamping intvec helper functions Waiman Long
2018-02-20 23:41 ` Luis R. Rodriguez
2018-02-21 16:58 ` Waiman Long
2018-02-19 16:53 ` [PATCH 2/3] sysctl: Warn when a clamped sysctl parameter is set out of range Waiman Long
2018-02-20 23:17 ` Andrew Morton [this message]
2018-02-20 23:55 ` Luis R. Rodriguez
2018-02-21 1:26 ` Kees Cook
2018-02-21 15:33 ` Waiman Long
2018-02-21 15:24 ` Waiman Long
2018-02-19 16:53 ` [PATCH 3/3] ipc: Clamp msgmni and shmmni to the real IPC_MNI limit Waiman Long
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