Messages in this thread | | | Date | Mon, 11 Feb 2019 22:32:50 +0100 | From | Christian Brauner <> | Subject | Re: + sysctl-return-einval-if-val-violates-minmax.patch added to -mm tree |
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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;
Christian
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