From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Tobin C. Harding" <me@tobin.cc>,
Matt Fleming <matt@codeblueprint.co.uk>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
LKML <linux-kernel@vger.kernel.org>,
"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>
Subject: Re: [GIT PULL] hash addresses printed with %p
Date: Thu, 30 Nov 2017 16:32:35 +0000 [thread overview]
Message-ID: <20171130163235.GA27849@kroah.com> (raw)
In-Reply-To: <CA+55aFwPXV0sXb+edcQc4epz0pWustZgJsoq95=a3OEDxynq7g@mail.gmail.com>
On Wed, Nov 29, 2017 at 01:36:25PM -0800, Linus Torvalds wrote:
> On Wed, Nov 29, 2017 at 1:14 PM, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> >
> > Not because %pK itself changed, but because the semantics of %p did.
> > The baseline moved, and the "safe" version did not.
>
> Btw, that baseline for me is now that I can do
>
> ./scripts/leaking_addresses.pl | wc -l
> 18
>
> and of those 18 hits, six are false positives (looks like bitmaps in
> the uevent keys).
>
> The remaining 12 are from the EFI runtime map files
> (/sys/firmware/efi/runtime-map/*). They should presumably not be
> world-readable, but sadly the kset_create_and_add() helper seems to do
> that by default.
>
> I think the sysfs code makes it insanely too easy to make things
> world-readable. You try to be careful, and mark things read-only etc,
> but __ATTR_RO() jkust means S_IRUGO, which means world-readable.
>
> There seems to be no convenient model for kobjects having better
> permissions. Greg?
They can just use __ATTR() which lets you set the exact mode settings
that are wanted.
Something like the patch below, which breaks the build as the
map_attributes are "odd", but you get the idea. The EFI developers can
fix this up properly :)
Note, this only accounts for 5 attributes, what is the whole list?
thanks,
greg k-h
diff --git a/drivers/firmware/efi/runtime-map.c b/drivers/firmware/efi/runtime-map.c
index 8e64b77aeac9..09444964c8d7 100644
--- a/drivers/firmware/efi/runtime-map.c
+++ b/drivers/firmware/efi/runtime-map.c
@@ -63,11 +63,11 @@ static ssize_t map_attr_show(struct kobject *kobj, struct attribute *attr,
return map_attr->show(entry, buf);
}
-static struct map_attribute map_type_attr = __ATTR_RO(type);
-static struct map_attribute map_phys_addr_attr = __ATTR_RO(phys_addr);
-static struct map_attribute map_virt_addr_attr = __ATTR_RO(virt_addr);
-static struct map_attribute map_num_pages_attr = __ATTR_RO(num_pages);
-static struct map_attribute map_attribute_attr = __ATTR_RO(attribute);
+static struct map_attribute map_type_attr = __ATTR(type, 0400, type_show, NULL);
+static struct map_attribute map_phys_addr_attr = __ATTR(phys_addr, 0400, phys_addr_show, NULL);
+static struct map_attribute map_virt_addr_attr = __ATTR(virt_addr, 0400, virt_addr_show, NULL);
+static struct map_attribute map_num_pages_attr = __ATTR(num_pages, 0400, num_pages_show, NULL);
+static struct map_attribute map_attribute_attr = __ATTR(attribute, 0400, attribute_show, NULL);
/*
* These are default attributes that are added for every memmap entry.
next prev parent reply other threads:[~2017-11-30 16:32 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-29 4:59 [GIT PULL] hash addresses printed with %p Tobin C. Harding
2017-11-29 19:22 ` Linus Torvalds
2017-11-29 19:39 ` Linus Torvalds
2017-11-29 20:54 ` Joe Perches
2017-11-29 21:05 ` Linus Torvalds
2017-11-29 21:31 ` Kees Cook
2017-11-29 21:08 ` Tobin C. Harding
2017-11-29 21:14 ` Linus Torvalds
2017-11-29 21:28 ` Tobin C. Harding
2017-11-29 21:36 ` Linus Torvalds
2017-11-30 16:32 ` Greg Kroah-Hartman [this message]
2017-11-30 17:10 ` Greg Kroah-Hartman
2017-11-30 17:18 ` Ard Biesheuvel
2017-12-01 9:48 ` Greg Kroah-Hartman
2017-12-01 9:54 ` Ard Biesheuvel
2017-12-01 15:34 ` Greg Kroah-Hartman
2017-12-01 16:33 ` Kees Cook
2017-12-02 8:51 ` Ard Biesheuvel
2017-12-02 22:22 ` Matt Fleming
2017-12-03 1:15 ` Dave Young
2017-12-04 2:02 ` Dave Young
2017-12-04 2:33 ` Joe Perches
2017-12-04 2:39 ` Dave Young
2017-12-04 7:36 ` Greg Kroah-Hartman
2017-12-04 9:29 ` Dave Young
2017-12-04 9:34 ` Greg Kroah-Hartman
2017-12-04 9:48 ` Ard Biesheuvel
2017-12-04 9:59 ` Greg Kroah-Hartman
2017-12-04 10:03 ` Ard Biesheuvel
2017-12-04 10:11 ` Greg Kroah-Hartman
2017-12-04 12:51 ` David Laight
2017-12-04 14:00 ` Greg Kroah-Hartman
2017-12-05 5:14 ` Dave Young
2017-12-05 8:09 ` Greg Kroah-Hartman
2017-12-05 8:45 ` Dave Young
2017-12-05 8:52 ` Greg Kroah-Hartman
2017-12-05 9:25 ` Ard Biesheuvel
2017-12-05 10:15 ` Greg Kroah-Hartman
2017-12-05 9:32 ` Dave Young
2017-12-05 9:24 ` Dave Young
2017-12-05 10:14 ` Greg Kroah-Hartman
2017-11-30 23:17 ` Linus Torvalds
2017-12-01 9:47 ` Greg Kroah-Hartman
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