From: ebiederm@xmission•com (Eric W. Biederman)
To: Andrew Morton <akpm@linux-foundation•org>
Cc: "Eric Dumazet" <eric.dumazet@gmail•com>,
"Américo Wang" <xiyou.wangcong@gmail•com>,
"Robin Holt" <holt@sgi•com>,
linux-kernel <linux-kernel@vger•kernel.org>,
"Willy Tarreau" <w@1wt•eu>,
"David S. Miller" <davem@davemloft•net>,
netdev@vger•kernel.org, "James Morris" <jmorris@namei•org>,
"Pekka Savola (ipv6)" <pekkas@netcore•fi>,
"Patrick McHardy" <kaber@trash•net>,
"Alexey Kuznetsov" <kuznet@ms2•inr.ac.ru>
Subject: Re: [PATCH] sysctl: fix min/max handling in __do_proc_doulongvec_minmax()
Date: Thu, 07 Oct 2010 12:38:22 -0700 [thread overview]
Message-ID: <m1vd5d3ia9.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <20101007121840.ca49e2ac.akpm@linux-foundation.org> (Andrew Morton's message of "Thu, 7 Oct 2010 12:18:40 -0700")
Andrew Morton <akpm@linux-foundation•org> writes:
> On Thu, 07 Oct 2010 18:59:03 +0200
> Eric Dumazet <eric.dumazet@gmail•com> wrote:
>> 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?
In 2.6.36 there are not any callers that pass in a vector of anything, I
don't know about linux-next. It looks to me like incrementing min and
max was simply a bug.
> I wonder if there's any documentation for this interface which just
> became wrong.
Or it just became right. Clearly no one has been expecting min
and max to be vectors.
Eric
next prev parent reply other threads:[~2010-10-07 19:38 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-02 13:17 [PATCH] sysctl: fix min/max handling in __do_proc_doulongvec_minmax() Eric Dumazet
2010-10-04 3:09 ` Américo Wang
2010-10-04 8:59 ` Robin Holt
2010-10-04 9:04 ` Eric Dumazet
2010-10-04 9:34 ` Américo Wang
2010-10-04 10:10 ` Eric Dumazet
2010-10-04 10:35 ` Américo Wang
2010-10-04 10:38 ` Eric Dumazet
2010-10-05 13:01 ` Américo Wang
2010-10-07 7:18 ` Américo Wang
2010-10-07 9:25 ` Américo Wang
2010-10-07 9:51 ` Eric Dumazet
2010-10-07 16:37 ` Eric W. Biederman
2010-10-07 16:59 ` Eric Dumazet
2010-10-07 19:18 ` Andrew Morton
2010-10-07 19:38 ` Eric W. Biederman [this message]
2010-10-08 16:22 ` Américo Wang
2010-10-08 16:13 ` Américo Wang
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