Messages in this thread | | | Date | Tue, 6 Nov 2007 13:34:05 +0200 | Subject | Re: [PATCH] Smackv10: Smack rules grammar + their stateful parser | From | "Ahmed S. Darwish" <> |
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Hi,
On Tue, Nov 06, 2007 at 09:56:51AM +0100, Adrian Bunk wrote: > On Tue, Nov 06, 2007 at 03:26:12AM -0500, Kyle Moffett wrote: > > On Nov 06, 2007, at 01:33:05, Adrian Bunk wrote: > >> Can you limit this to 7bit ASCII and use isascii() somewhere? > >> > >> Otherwise I'd expect funny things to happen when you e.g. use isspace() on > >> the UTF-8 encoded character ??. > > > > Actually, you don't need to. You tell them it expects UTF-8 encoded > > strings and be done with it. All US-ASCII characters from 0 through 127 > > (IE: high bit clear) are exactly the same in UTF-8, and UTF-8 special > > characters have the high bit set in all bytes. Therefore you just assume > > that anything with the high bit set is part of a word and you can handle > > basic UTF-8. (It doesn't work on special UTF-8 space characters like > > nonbreaking space and similar, but handling those is significantly more > > complicated). > > The documentations says: > "Smack labels cannot contain unprintable characters or the "/" (slash) > character." > > What you propose might contain unprintable characters, and it might even > be invalid UTF-8. >
As far as I understand the problem now, isspace() accepts the 0xa0 character which might collide with some of UTF-8 encoded characters cause the high bit is set.
I used "if (!isspace(c) && !isgraph(c)) return -EINVAL;" to test rules' characters validity which seems not enough. I'll add !isascii(c) in the condition and ask Casey to change the documentation to be something like:
Smack labels are represented in ASCII characters, they cannot contain unprintable characters or the '/' (slash) character.
and in write(): if (!isascii(c) return -EINVAL; if (!isspace(c) && !isgraph(c)) return -EINVAL;
This satisfy above customized labels rule, right ?
Regards,
-- Ahmed S. Darwish Homepage: http://darwish.07.googlepages.com Blog: http://darwish-07.blogspot.com - 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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