From: XIAO Gang <xiao@unice.fr>
To: linux-kernel@vger.kernel.org
Subject: Suggestion on "int len" sanity
Date: Wed, 01 Jun 2005 09:06:33 +0200 [thread overview]
Message-ID: <429D5E79.2010707@unice.fr> (raw)
I would like to make a security suggestion.
There are many length variables in the kernel, locally declared as "len"
or "length", either as "int", "unsigned int" or "size_t". However,
declaring a length as "int" leads easily to an erroneous situation, as
the author (or even a code checker) might make the implicite hypothesis
that the length is positive, so that it is enough to make a sanity check
of the kind
if (length > limit) ERROR;
which is not enough.
On the other hand, when a variable is named "len" or "length", it is
usually used for length and never should go negative. So could I suggest
that the declarations of these variables to be uniformized to "size_t",
via a gradual but sysmatic cleanup?
--
XIAO Gang (~{P$8U~}) xiao@unice.fr
home page: pcmath126.unice.fr/xiao.html
next reply other threads:[~2005-06-01 7:06 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-06-01 7:06 XIAO Gang [this message]
2005-06-01 13:46 ` Suggestion on "int len" sanity Jörn Engel
2005-06-01 20:39 ` Willy Tarreau
2005-06-03 9:42 ` Geert Uytterhoeven
2005-06-03 12:47 ` Takashi Iwai
-- strict thread matches above, loose matches on Subject: below --
2005-06-02 7:28 XIAO Gang
2005-06-02 8:48 ` Jörn Engel
2005-06-02 9:12 ` XIAO Gang
2005-06-02 9:47 ` Jörn Engel
2005-06-03 9:45 ` Geert Uytterhoeven
2005-06-03 12:20 ` Al Viro
2005-06-03 14:19 ` Jörn Engel
2005-06-03 12:28 ` Andreas Schwab
2005-06-03 12:43 ` Geert Uytterhoeven
2005-06-03 14:38 ` Andreas Schwab
2005-06-03 18:04 ` randy_dunlap
2005-06-03 18:09 ` Lars Marowsky-Bree
2005-06-03 18:16 ` randy_dunlap
2005-06-04 11:28 ` Christoph Hellwig
2005-06-04 16:58 ` randy_dunlap
2005-06-04 17:07 ` Jörn Engel
2005-06-04 17:11 ` randy_dunlap
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