[PATCH 0/2] sysctl: cap file-max value at ULONG_MAX

From: Christian Brauner <christian@brauner.io>
To: keescook@chromium.org, linux-kernel@vger.kernel.org
Cc: ebiederm@xmission.com, mcgrof@kernel.org,
	akpm@linux-foundation.org, joe.lawrence@redhat.com,
	longman@redhat.com, Christian Brauner <christian@brauner.io>
Subject: [PATCH 0/2] sysctl: cap file-max value at ULONG_MAX
Date: Sun, 14 Oct 2018 15:25:08 +0200	[thread overview]
Message-ID: <20181014132510.25943-1-christian@brauner.io> (raw)

Hey,

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: add overflow detection to proc_get_long()
  sysctl: handle overflow for file-max

 kernel/sysctl.c | 54 ++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 42 insertions(+), 12 deletions(-)

-- 
2.17.1