From: Matthew Wilcox <willy@infradead.org>
To: Kees Cook <keescook@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [RFC][PATCH] lkdtm/usercopy: Add tests for other memory types
Date: Thu, 12 May 2022 19:56:13 +0100 [thread overview]
Message-ID: <Yn1YTZkWVWfXk5Q8@casper.infradead.org> (raw)
In-Reply-To: <20220512183613.1069697-1-keescook@chromium.org>
On Thu, May 12, 2022 at 11:36:13AM -0700, Kees Cook wrote:
> +static void lkdtm_USERCOPY_FOLIO(void)
> +{
> + struct folio *folio;
> + void *addr;
> +
> + /*
> + * FIXME: Folio checking currently misses 0-order allocations, so
> + * allocate and bump forward to the last page.
> + */
> + folio = folio_alloc(GFP_KERNEL | __GFP_ZERO, 1);
> + if (!folio) {
> + pr_err("folio_alloc() failed!?\n");
> + return;
> + }
> + addr = page_address(&folio->page);
Ideally, code shouldn't be using &folio->page. If it is, we have a
gap in the folio API. Fortunately, we have folio_address().
> + if (addr) {
> + do_usercopy_page_span("folio", addr + PAGE_SIZE);
> + }
> + folio_put(folio);
> +}
Other than that, this looks sane to me.
next prev parent reply other threads:[~2022-05-12 18:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-12 18:36 [RFC][PATCH] lkdtm/usercopy: Add tests for other memory types Kees Cook
2022-05-12 18:56 ` Matthew Wilcox [this message]
2022-05-12 19:12 ` Kees Cook
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