Messages in this thread | | | Date | Thu, 7 Oct 2010 12:18:40 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] sysctl: fix min/max handling in __do_proc_doulongvec_minmax() |
| |
On Thu, 07 Oct 2010 18:59:03 +0200 Eric Dumazet <eric.dumazet@gmail.com> wrote:
> Le jeudi 07 octobre 2010 __ 09:37 -0700, Eric W. Biederman a __crit : > > > The difference between long handling and int handling is a > > usability issue. I don't expect we will be exporting new > > vectors via sysctl, so the conversion of a handful of vectors > > from int to long is where this is most likely to be used. > > > > I skimmed through all of what I presume are the current users > > aka linux-2.6.36-rcX and there don't appear to be any users > > of proc_dounlongvec_minmax that use it's vector properties there. > > > > Which doubly tells me that incrementing the min and max pointers > > is not what we want to do. > > > > Thats fine by me, thanks Eric. > > Andrew, please remove previous patch from your tree and replace it by > following one : > > [PATCH v2] sysctl: fix min/max handling in __do_proc_doulongvec_minmax() > > When proc_doulongvec_minmax() is used with an array of longs, > and no min/max check requested (.extra1 or .extra2 being NULL), we > dereference a NULL pointer for the second element of the array. > > Noticed while doing some changes in network stack for the "16TB problem" > > Fix is to not change min & max pointers in > __do_proc_doulongvec_minmax(), so that all elements of the vector share > an unique min/max limit, like proc_dointvec_minmax(). > > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> > --- > kernel/sysctl.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > index f88552c..8e45451 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -2485,7 +2485,7 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int > kbuf[left] = 0; > } > > - for (; left && vleft--; i++, min++, max++, first=0) { > + for (; left && vleft--; i++, first=0) { > unsigned long val; > > if (write) {
Did we check to see whether any present callers are passing in pointers to arrays of min/max values?
I wonder if there's any documentation for this interface which just became wrong.
| |