From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luis Chamberlain Subject: Re: + sysctl-return-einval-if-val-violates-minmax.patch added to -mm tree Date: Mon, 11 Feb 2019 13:41:06 -0800 Message-ID: <20190211214106.GW11489@garbanzo.do-not-panic.com> References: <20190211210632.Nfd0f%akpm@linux-foundation.org> <20190211211716.GA31039@avx2> <20190211211917.kq2ahdkhoe36obhp@brauner.io> <20190211212523.GU11489@garbanzo.do-not-panic.com> <20190211213249.lta2pithpf5w6w7m@brauner.io> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190211213249.lta2pithpf5w6w7m@brauner.io> Sender: linux-kernel-owner@vger.kernel.org To: Christian Brauner Cc: Alexey Dobriyan , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk, longman@redhat.com, linux@dominikbrodowski.net, keescook@chromium.org, joe.lawrence@redhat.com, ebiederm@xmission.com, linux-api@vger.kernel.org List-Id: linux-api@vger.kernel.org On Mon, Feb 11, 2019 at 10:32:50PM +0100, Christian Brauner wrote: > On Mon, Feb 11, 2019 at 01:25:23PM -0800, Luis Chamberlain wrote: > > On Mon, Feb 11, 2019 at 10:19:19PM +0100, Christian Brauner wrote: > > > On Tue, Feb 12, 2019 at 12:17:16AM +0300, Alexey Dobriyan wrote: > > > > On Mon, Feb 11, 2019 at 01:06:32PM -0800, akpm@linux-foundation.org wrote: > > > > > > > > > @@ -2848,8 +2848,10 @@ static int __do_proc_doulongvec_minmax(v > > > > > > > > > - if ((min && val < *min) || (max && val > *max)) > > > > > - continue; > > > > > + if ((min && val < *min) || (max && val > *max)) { > > > > > + err = -EINVAL; > > > > > > > > I was asked to return ERANGE in kstrto*(). > > > > > > I think we discussed ERANGE vs EINVAL and decided EINVAL because there > > > was precedence for other sysctls already. > > > > Can you do a proper audit and see? > > If you look at proc_get_long() right now you can see that when the > buffer we use to parse the number is exceeded we return EINVAL. In short > if you do right now: > > echo 1844674407370955161600000 > /proc/sys/fs/file-max > > that would exceed the buffer in proc_get_long() and you already get > EINVAL for all such cases. If we now change this to ERANGE we would > return: > > echo 18446744073709551616 > /proc/sys/fs/file-max -> ERANGE > echo 1844674407370955161600000 > /proc/sys/fs/file-max -> EINVAL > > which would be very confusing. For consistency we should use EINVAL. > > See kernel/sysctl.c: > > /* We don't know if the next char is whitespace thus we may accept > * invalid integers (e.g. 1234...a) or two integers instead of one > * (e.g. 123...1). So lets not allow such large numbers. */ > if (len == TMPBUFLEN - 1) > return -EINVAL; Thanks this works for me. Luis