From: Joe Perches <joe@perches.com>
To: David Laight <David.Laight@ACULAB.COM>
Cc: Andreas Schwab <schwab@linux-m68k.org>,
Dan Carpenter <dan.carpenter@oracle.com>,
Karsten Keil <isdn@linux-pingi.de>,
"David S. Miller" <davem@davemloft.net>,
Masanari Iida <standby24x7@gmail.com>,
netdev@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [patch] isdn: fix a wrapping bug in isdn_ppp_ioctl()
Date: Wed, 10 Oct 2012 08:52:22 -0700 [thread overview]
Message-ID: <1349884342.2035.1.camel@joe-AO722> (raw)
In-Reply-To: <AE90C24D6B3A694183C094C60CF0A2F6026B7034@saturn3.aculab.com>
On Wed, 2012-10-10 at 16:44 +0100, David Laight wrote:
> > On Wed, 2012-10-10 at 15:59 +0100, David Laight wrote:
> > > Seems to me the code is expecting 256 bits of data, not any multiple of int,
> > > long or anything else.
> >
> > include/linux/isdn_ppp.h:#define PPPIOCGCOMPRESSORS _IOR('t',134,unsigned long [8])
>
> That doesn't mean the whole thing makes any sense on 64bit systems.
> A whole load of historic code used 'long' to ensure 32bit.
> Some of that might have crept into Linux sources.
Very true, but it's exported via copy_to_user.
> Since I suspect there are a maximum of 256 bits on both 32 and 64bit
> systems, I wouldn't like to guess exactly how any particular 64bit
> application chooses to check the bitmap.
>
> The ioctl constant may be wrong on 64 bit systems.
shrug. Not much to do about it now.
isdn isn't very active.
Karsten? What do you think?
next prev parent reply other threads:[~2012-10-10 15:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-10 9:42 [patch] isdn: fix a wrapping bug in isdn_ppp_ioctl() Dan Carpenter
2012-10-10 10:19 ` Joe Perches
2012-10-10 10:41 ` Joe Perches
2012-10-10 10:42 ` David Laight
2012-10-10 11:15 ` Joe Perches
2012-10-10 12:05 ` Andreas Schwab
2012-10-10 13:00 ` Joe Perches
2012-10-10 13:58 ` Andreas Schwab
2012-10-10 14:41 ` Joe Perches
2012-10-10 14:59 ` David Laight
2012-10-10 15:19 ` Joe Perches
2012-10-10 15:44 ` David Laight
2012-10-10 15:52 ` Joe Perches [this message]
2012-10-12 7:49 ` Karsten Keil
2012-10-11 2:46 ` David Miller
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