From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Kees Cook <keescook@chromium.org>
Cc: linux-kernel@vger.kernel.org, patches@lists.linux.dev,
"Andreas Noever" <andreas.noever@gmail.com>,
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Subject: Re: [PATCH v4 2/6] treewide: use prandom_u32_max() when possible
Date: Fri, 7 Oct 2022 21:21:20 -0600 [thread overview]
Message-ID: <Y0DssPFp2rY+TrPp@zx2c4.com> (raw)
In-Reply-To: <202210071241.445289C5@keescook>
On Fri, Oct 07, 2022 at 03:47:44PM -0700, Kees Cook wrote:
> > diff --git a/lib/test_vmalloc.c b/lib/test_vmalloc.c
> > index 4f2f2d1bac56..56ffaa8dd3f6 100644
> > --- a/lib/test_vmalloc.c
> > +++ b/lib/test_vmalloc.c
> > @@ -151,9 +151,7 @@ static int random_size_alloc_test(void)
> > int i;
> >
> > for (i = 0; i < test_loop_count; i++) {
> > - n = prandom_u32();
> > - n = (n % 100) + 1;
> > -
> > + n = prandom_u32_max(n % 100) + 1;
> > p = vmalloc(n * PAGE_SIZE);
> >
> > if (!p)
>
> This looks wrong. Cocci says:
>
> - n = prandom_u32();
> - n = (n % 100) + 1;
> + n = prandom_u32_max(100) + 1;
I agree that's wrong, but what rule did you use to make Cocci generate
that?
Jason
next prev parent reply other threads:[~2022-10-08 3:21 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-07 18:01 [PATCH v4 0/6] treewide cleanup of random integer usage Jason A. Donenfeld
2022-10-07 18:01 ` [PATCH v4 1/6] treewide: use prandom_u32_max() when possible, mechanically Jason A. Donenfeld
2022-10-07 21:14 ` Darrick J. Wong
2022-10-07 18:01 ` [PATCH v4 2/6] treewide: use prandom_u32_max() when possible Jason A. Donenfeld
2022-10-07 21:17 ` Darrick J. Wong
2022-10-08 1:28 ` Jason A. Donenfeld
2022-10-07 22:47 ` Kees Cook
2022-10-08 2:21 ` Jason A. Donenfeld
2022-10-08 3:21 ` Jason A. Donenfeld [this message]
2022-10-08 22:08 ` David Laight
2022-10-08 22:19 ` Jason A. Donenfeld
2022-10-07 18:01 ` [PATCH v4 3/6] treewide: use get_random_{u8,u16}() " Jason A. Donenfeld
2022-10-07 18:01 ` [PATCH v4 4/6] treewide: use get_random_u32() " Jason A. Donenfeld
2022-10-07 20:34 ` Rolf Eike Beer
2022-10-08 1:40 ` Jason A. Donenfeld
2022-10-07 21:19 ` Darrick J. Wong
2022-10-08 22:18 ` David Laight
2022-10-08 22:37 ` Jason A. Donenfeld
2022-10-09 0:26 ` Jason A. Donenfeld
2022-10-07 18:01 ` [PATCH v4 5/6] treewide: use get_random_bytes " Jason A. Donenfeld
2022-10-07 18:01 ` [PATCH v4 6/6] prandom: remove unused functions Jason A. Donenfeld
2022-10-08 3:50 [PATCH v4 2/6] treewide: use prandom_u32_max() when possible Kees Cook
2022-10-08 7:33 ` Julia Lawall
2022-10-08 18:16 ` Andy Shevchenko
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