linux-kernel - Re: [RESEND PATCH v3 2/2] sysctl: handle overflow for file-max

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Date:   Tue, 8 Jan 2019 08:01:10 +0100
From:   Dominik Brodowski <linux@...inikbrodowski.net>
To:     Christian Brauner <christian@...uner.io>
Cc:     akpm@...ux-foundation.org, keescook@...omium.org,
        linux-kernel@...r.kernel.org, ebiederm@...ssion.com,
        mcgrof@...nel.org, joe.lawrence@...hat.com, longman@...hat.com,
        viro@...iv.linux.org.uk, adobriyan@...il.com,
        linux-api@...r.kernel.org
Subject: Re: [RESEND PATCH v3 2/2] sysctl: handle overflow for file-max

On Mon, Jan 07, 2019 at 11:27:00PM +0100, Christian Brauner wrote:
> @@ -2833,6 +2836,10 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int
>  				break;
>  			if (neg)
>  				continue;
> +			if ((max && val > *max) || (min && val < *min)) {
> +				err = -EINVAL;
> +				break;
> +			}
>  			val = convmul * val / convdiv;
>  			if ((min && val < *min) || (max && val > *max))
>  				continue;

This is a generic change which affects all users of
do_proc_doulongvec_minmax() that have extra1 or extra2 set. In sysctl.c, I
do not see another user of proc_doulongvec_minmax() that has extra1 or
extra2 set. However, have you verified whether your patch changes the
behaviour for other files that make use of proc_doulongvec_minmax() or
proc_doulongvec_ms_jiffies_minmax(), and not only of the file-max sysctl?

Thanks,
	Dominik