linux-kernel - [PATCH v1 0/2] sysctl: cap file-max value at ULONG

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Message-Id: <20181015105544.4395-1-christian@brauner.io>
Date:   Mon, 15 Oct 2018 12:55:42 +0200
From:   Christian Brauner <christian@...uner.io>
To:     keescook@...omium.org, linux-kernel@...r.kernel.org
Cc:     ebiederm@...ssion.com, mcgrof@...nel.org,
        akpm@...ux-foundation.org, joe.lawrence@...hat.com,
        longman@...hat.com, linux@...inikbrodowski.net,
        viro@...iv.linux.org.uk, Christian Brauner <christian@...uner.io>
Subject: [PATCH v1 0/2] sysctl: cap file-max value at ULONG_MAX

Hey,

Here is v1 of this patchset. Changelogs are in the individual commits.

Currently, when writing

echo 18446744073709551616 > /proc/sys/fs/file-max

/proc/sys/fs/file-max will overflow and be set to 0. That quickly
crashes the system. Let's detect the overflow and set to ULONG_MAX in
this case effectively capping the value.

The patch tries to ensure that there is no other user visible change in
behavior for other values. Only when a maximum value is set for a
specific sysctl will it be capped on overflow. The details are outlined
in the commit message of the first commit.

(This patchset is in reference to https://lkml.org/lkml/2018/10/11/585.)

Thanks!
Christian

Christian Brauner (2):
  sysctl: cap to ULONG_MAX in proc_get_long()
  sysctl: handle overflow for file-max

 kernel/sysctl.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

-- 
2.17.1