From: Eric Dumazet <eric.dumazet@gmail.com>
To: Xi Wang <xi.wang@gmail.com>
Cc: Tom Herbert <therbert@google.com>,
"David S. Miller" <davem@davemloft.net>,
netdev@vger.kernel.org
Subject: Re: [PATCH v2] rps: fix insufficient bounds checking in store_rps_dev_flow_table_cnt()
Date: Fri, 23 Dec 2011 06:16:30 +0100 [thread overview]
Message-ID: <1324617390.2674.13.camel@edumazet-laptop> (raw)
In-Reply-To: <ACB00AE8-CFEF-4535-9242-1B5C44F05C13@gmail.com>
Le vendredi 23 décembre 2011 à 00:10 -0500, Xi Wang a écrit :
> On Dec 22, 2011, at 11:53 PM, Eric Dumazet wrote:
> > All I wanted to say is that while mixing INT_MAX/ULONG_MAX, you could
> > have spotted the other bug in the code :
> >
> > unsigned int count;
> >
> > count = simple_strtoul(buf, &endp, 0);
>
> Are you suggesting to change the type of "count" to unsigned long?
> That seems like a separate issue from the bounds checking part.
>
> I don't see the possible 32-bit truncation here is a serious issue though.
> The user could even echo "128abc" into rps_flow_cnt and simple_strtoul()
> would be happy to pick 128.
>
32 bit truncation _is_ a bound checking problem too.
Really, mixing INT_MAX / ULONG_MAX is ugly, this should had ring a bell
when writing such hard to read code.
You cannot claim to give more range to 64bit platform, yet not spotting
the 32bit truncation issue.
When fixing a bug, its always a good thing to look things around, and
try to check the whole function.
next prev parent reply other threads:[~2011-12-23 5:16 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-21 18:50 [PATCH] rps: fix insufficient bounds checking in store_rps_dev_flow_table_cnt() Xi Wang
2011-12-21 19:22 ` Eric Dumazet
2011-12-21 19:41 ` David Miller
2011-12-21 23:41 ` Xi Wang
2011-12-22 23:35 ` [PATCH v2] " Xi Wang
2011-12-23 3:37 ` David Miller
2011-12-23 4:10 ` Eric Dumazet
2011-12-23 4:44 ` Xi Wang
2011-12-23 4:53 ` Eric Dumazet
2011-12-23 5:10 ` Xi Wang
2011-12-23 5:16 ` Eric Dumazet [this message]
2011-12-23 5:35 ` Eric Dumazet
2011-12-23 5:56 ` Xi Wang
2011-12-23 13:06 ` Eric Dumazet
2011-12-23 14:30 ` Xi Wang
2011-12-23 14:53 ` Eric Dumazet
2011-12-23 15:07 ` Xi Wang
2011-12-24 16:56 ` [PATCH net-next] rfs: better sizing of dev_flow_table Eric Dumazet
2011-12-24 21:19 ` David Miller
2011-12-23 5:49 ` [PATCH v2] rps: fix insufficient bounds checking in store_rps_dev_flow_table_cnt() Xi Wang
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