From: Al Viro <viro@zeniv.linux.org.uk>
To: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Tycho Andersen <tycho@tycho.ws>,
linux-sparse@vger.kernel.org,
kernel-hardening@lists.openwall.com,
linux-kernel@vger.kernel.org
Subject: Re: [RFC v1] copy_{to,from}_user(): only inline when !__CHECKER__
Date: Sun, 9 Dec 2018 21:56:51 +0000 [thread overview]
Message-ID: <20181209215651.GD2217@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20181209213951.kumz33u6prb2seqz@ltop.local>
On Sun, Dec 09, 2018 at 10:39:52PM +0100, Luc Van Oostenryck wrote:
> There are several more or less bad/good solutions, like:
> * add raw_copy_{to,from}_user() in the list of checked function
> (not inlined in most archs).
> * add a new annotation to force sparse to check the byte count
> (I'm thinking about __range__/OP_RANGE or something similar).
> * do these checks before functions are inlined (but then some
> constant count could not yet be seen as constant).
* just spell it out in copy_to_user() itself - as in
#ifdef C_T_U_SIZE_LIMIT
if (__builtin_constant_p(count) && count > C_T_U_SIZE_LIMIT)
/* something warning-triggering */
#endif
in the beginning of copy_from_user(). Or simply
#ifdef C_T_U_SIZE_LIMIT
BUILD_BUG_ON(__builtin_constant_p(count) && count > C_T_U_SIZE_LIMIT);
#endif
in there...
next prev parent reply other threads:[~2018-12-09 21:56 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-09 20:44 [RFC v1] copy_{to,from}_user(): only inline when !__CHECKER__ Tycho Andersen
2018-12-09 21:02 ` Al Viro
2018-12-09 21:25 ` Tycho Andersen
2018-12-09 21:39 ` Luc Van Oostenryck
2018-12-09 21:53 ` Tycho Andersen
2018-12-09 21:56 ` Al Viro [this message]
2018-12-09 22:08 ` Luc Van Oostenryck
2018-12-09 21:46 ` Al Viro
2018-12-09 21:56 ` Tycho Andersen
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