Messages in this thread | | | Date | Fri, 3 Jun 2005 11:42:23 +0200 (CEST) | From | Geert Uytterhoeven <> | Subject | Re: Suggestion on "int len" sanity |
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On Wed, 1 Jun 2005, Willy Tarreau wrote: > On Wed, Jun 01, 2005 at 09:06:33AM +0200, XIAO Gang wrote: > > 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? > > Probably true for most cases, but be careful of code which would use > -1 to report some errors if such thing exists.
In that case, use ssize_t.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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