Messages in this thread | | | Date | Tue, 14 Jun 2016 13:19:06 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 1/1] kernel/sysctl.c: avoid overflow |
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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.
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