From: "Ahmed S. Darwish" <darwish.07@gmail.com>
To: "Jakob Oestergaard" <jakob@unthought.net>
Cc: "Casey Schaufler" <casey@schaufler-ca.com>,
akpm@osdl.org, torvalds@osdl.org,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org, "Al Viro" <viro@ftp.linux.org.uk>
Subject: Re: [PATCH] Smackv10: Smack rules grammar + their stateful parser(2)
Date: Sat, 10 Nov 2007 21:45:06 +0200 [thread overview]
Message-ID: <1865922a0711101145g768fe96p74b400e31f4120a1@mail.gmail.com> (raw)
In-Reply-To: <20071110170557.GA21977@unthought.net>
On Nov 10, 2007 7:05 PM, Jakob Oestergaard <jakob@unthought.net> wrote:
> ...
> > I've double-checked the code for any possible off-by-one/overflow
> > errors.
> ...
>
> Two things caught my eye.
>
> ...
> > + case bol:
> > + case subject:
> > + if (*label_len >= SMK_MAXLEN)
> > + goto out;
> > + subjectstr[(*label_len)++] = data[i];
>
> Why is the '>' necessary? Could it happen that you had incremented past the
> point of equality?
>
> If that could not happen, then in my oppinion '>=' is very misleading when '=='
> is really what is needed.
>
Indeed, you're absolutely right.
> ...
> > + case object:
> > + if (*prevstate == blank) {
> > + subjectstr[*label_len] = '\0';
> > + *label_len = 0;
> > + }
>
> I wonder why it is valid to uncritically use the already incremented label_len
> here, without checking its value (like is done above).
>
> It seems strangely asymmetrical. I'm not saying it's wrong, because there may
> be a subtle reason as to why it's not, but if that's the case then I think that
> subtle reason should be documented with a comment.
>
Maximum value label_len could reach is "SMK_MAXLEN". The subjectstr
and objectstr arrays are of "SMK_MAXLEN + 1" length. So I think no
danger is here.
Yes, this deserved a comment.
> ...
> > + case access:
> > + if (*prevstate == blank) {
> > + objectstr[*label_len] = '\0';
> > + *label_len = 0;
> > + }
>
> Same applies here.
>
> / jakob
>
Good spots, thanks a lot for the review.
Regards,
--
Ahmed S. Darwish
Homepage: http://darwish.07.googlepages.com
Blog: http://darwish-07.blogspot.com
next prev parent reply other threads:[~2007-11-10 19:45 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-02 20:50 [PATCH] Version 10 (2.6.24-rc1) Smack: Simplified Mandatory Access Control Kernel Casey Schaufler
2007-11-03 16:43 ` [PATCH] Smackv10: Smack rules grammar + their stateful parser Ahmed S. Darwish
2007-11-03 18:30 ` Kyle Moffett
2007-11-03 22:12 ` Ahmed S. Darwish
2007-11-04 12:28 ` Pavel Machek
2007-11-04 13:23 ` Ahmed S. Darwish
2007-11-04 16:37 ` Casey Schaufler
2007-11-05 9:41 ` Ahmed S. Darwish
2007-11-05 16:21 ` Linus Torvalds
2007-11-05 21:56 ` Tetsuo Handa
2007-11-06 10:00 ` Adrian Bunk
2007-11-06 12:27 ` Tetsuo Handa
2007-11-06 13:58 ` Adrian Bunk
2007-11-06 14:32 ` Tetsuo Handa
2007-11-06 14:59 ` Adrian Bunk
2007-11-06 15:27 ` Tetsuo Handa
2007-11-06 22:42 ` Adrian Bunk
2007-11-05 23:38 ` Ahmed S. Darwish
2007-11-06 8:06 ` Adrian Bunk
2007-11-06 15:39 ` Linus Torvalds
2007-11-06 23:00 ` Adrian Bunk
2007-11-06 23:08 ` Linus Torvalds
2007-11-07 0:07 ` Adrian Bunk
2007-11-07 0:27 ` Linus Torvalds
2007-11-07 0:43 ` Adrian Bunk
2007-11-07 1:03 ` Tetsuo Handa
2007-11-07 1:06 ` Linus Torvalds
2007-11-07 1:59 ` Adrian Bunk
2007-11-07 4:09 ` Linus Torvalds
2007-11-07 15:08 ` Alan Cox
2007-11-04 20:06 ` Ahmed S. Darwish
2007-11-05 0:56 ` [PATCH] Smackv10: Smack rules grammar + their stateful parser(2) Ahmed S. Darwish
2007-11-10 17:05 ` Jakob Oestergaard
2007-11-10 19:45 ` Ahmed S. Darwish [this message]
2007-11-11 12:44 ` Pavel Machek
2007-11-11 18:37 ` Ahmed S. Darwish
2007-11-06 6:33 ` [PATCH] Smackv10: Smack rules grammar + their stateful parser Adrian Bunk
2007-11-06 8:26 ` Kyle Moffett
2007-11-06 8:56 ` Adrian Bunk
2007-11-06 11:02 ` Alan Cox
2007-11-06 11:34 ` Ahmed S. Darwish
2007-11-06 11:47 ` Adrian Bunk
2007-11-06 12:23 ` Ahmed S. Darwish
2007-11-06 12:49 ` Kyle Moffett
2007-11-06 13:34 ` Adrian Bunk
2007-11-06 14:05 ` Ahmed S. Darwish
2007-11-06 14:10 ` Adrian Bunk
2007-11-06 14:30 ` Ahmed S. Darwish
2007-11-06 15:53 ` Linus Torvalds
2007-11-07 10:56 ` [PATCH] Fix isspace() and other ctype.h functions to ignore chars 128-255 Kyle Moffett
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