lkml.org 
[lkml]   [2016]   [Jun]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/1] kernel/sysctl.c: avoid overflow
On Sat, 11 Jun 2016 03:33:08 +0200 Heinrich Schuchardt <xypron.glpk@gmx.de> wrote:

> An undetected overflow may occur in do_proc_dointvec_minmax_conv_param.
>
> ...
>
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -2313,7 +2313,17 @@ static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
> {
> struct do_proc_dointvec_minmax_conv_param *param = data;
> if (write) {
> - int val = *negp ? -*lvalp : *lvalp;
> + int val;
> +
> + if (*negp) {
> + if (*lvalp > (unsigned long) INT_MAX + 1)
> + return -EINVAL;
> + val = -*lvalp;
> + } else {
> + if (*lvalp > (unsigned long) INT_MAX)
> + return -EINVAL;
> + val = *lvalp;
> + }
> if ((param->min && *param->min > val) ||
> (param->max && *param->max < val))
> return -EINVAL;

hm.

What happens if someone does

echo -1 > /proc/foo

expecting to get 0xffffffff? That's a reasonable shorthand, and if we
change that to spit out EINVAL then people's stuff may break.

\
 
 \ /
  Last update: 2016-06-14 23:01    [W:0.137 / U:0.744 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site