From: Michael Ellerman <mpe@ellerman.id.au>
To: linux-kernel@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>,
Balbir Singh <bsingharora@gmail.com>,
Daniel Micay <danielmicay@gmail.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Rik van Riel <riel@redhat.com>,
Casey Schaufler <casey@schaufler-ca.com>,
PaX Team <pageexec@freemail.hu>,
Brad Spengler <spender@grsecurity.net>,
Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Tony Luck <tony.luck@intel.com>,
Fenghua Yu <fenghua.yu@intel.com>,
"David S. Miller" <davem@davemloft.net>,
x86@kernel.org, Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@suse.de>,
Mathias
Subject: Re: [PATCH v3 02/11] mm: Hardened usercopy
Date: Thu, 21 Jul 2016 16:52:09 +1000 [thread overview]
Message-ID: <15834.7418685027$1469083955@news.gmane.org> (raw)
In-Reply-To: <1468619065-3222-3-git-send-email-keescook@chromium.org>
Kees Cook <keescook@chromium.org> writes:
> diff --git a/mm/usercopy.c b/mm/usercopy.c
> new file mode 100644
> index 000000000000..e4bf4e7ccdf6
> --- /dev/null
> +++ b/mm/usercopy.c
> @@ -0,0 +1,234 @@
...
> +
> +/*
> + * Checks if a given pointer and length is contained by the current
> + * stack frame (if possible).
> + *
> + * 0: not at all on the stack
> + * 1: fully within a valid stack frame
> + * 2: fully on the stack (when can't do frame-checking)
> + * -1: error condition (invalid stack position or bad stack frame)
> + */
> +static noinline int check_stack_object(const void *obj, unsigned long len)
> +{
> + const void * const stack = task_stack_page(current);
> + const void * const stackend = stack + THREAD_SIZE;
That allows access to the entire stack, including the struct thread_info,
is that what we want - it seems dangerous? Or did I miss a check
somewhere else?
We have end_of_stack() which computes the end of the stack taking
thread_info into account (end being the opposite of your end above).
cheers
next prev parent reply other threads:[~2016-07-21 6:52 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-15 21:44 [PATCH v3 00/11] mm: Hardened usercopy Kees Cook
2016-07-15 21:44 ` [PATCH v3 01/11] mm: Implement stack frame object validation Kees Cook
2016-07-15 21:44 ` [PATCH v3 02/11] mm: Hardened usercopy Kees Cook
2016-07-19 1:06 ` Laura Abbott
2016-07-19 18:48 ` Kees Cook
2016-07-19 22:00 ` [PATCH] mm: Add is_migrate_cma_page Laura Abbott
2016-07-19 22:40 ` Kees Cook
2016-07-20 10:24 ` [PATCH v3 02/11] mm: Hardened usercopy Balbir Singh
2016-07-20 15:36 ` Laura Abbott
2016-07-19 1:52 ` Laura Abbott
2016-07-19 19:12 ` Kees Cook
2016-07-19 22:55 ` Kees Cook
2016-07-19 9:21 ` Christian Borntraeger
2016-07-19 19:31 ` Kees Cook
2016-07-19 20:14 ` Christian Borntraeger
2016-07-19 20:34 ` Kees Cook
2016-07-19 20:44 ` Christian Borntraeger
2016-07-21 6:52 ` Michael Ellerman
2016-07-21 6:52 ` Michael Ellerman [this message]
2016-07-21 6:52 ` Michael Ellerman
2016-07-21 6:52 ` Michael Ellerman
2016-07-21 6:52 ` Michael Ellerman
[not found] ` <5790711f.2350420a.b4287.2cc0SMTPIN_ADDED_BROKEN@mx.google.com>
2016-07-21 18:34 ` Kees Cook
2016-07-22 17:45 ` Josh Poimboeuf
2016-07-25 9:27 ` David Laight
2016-07-26 2:09 ` Michael Ellerman
2016-07-26 2:03 ` Michael Ellerman
2016-07-26 4:46 ` Kees Cook
2016-07-15 21:44 ` [PATCH v3 03/11] x86/uaccess: Enable hardened usercopy Kees Cook
2016-07-15 21:44 ` [PATCH v3 04/11] ARM: uaccess: " Kees Cook
2016-07-15 21:44 ` [PATCH v3 05/11] arm64/uaccess: " Kees Cook
2016-07-15 21:44 ` [PATCH v3 06/11] ia64/uaccess: " Kees Cook
2016-07-15 21:44 ` [PATCH v3 07/11] powerpc/uaccess: " Kees Cook
2016-07-15 21:44 ` [PATCH v3 08/11] sparc/uaccess: " Kees Cook
2016-07-15 21:44 ` [PATCH v3 09/11] s390/uaccess: " Kees Cook
2016-07-15 21:44 ` [PATCH v3 10/11] mm: SLAB hardened usercopy support Kees Cook
2016-07-15 21:44 ` [PATCH v3 11/11] mm: SLUB " Kees Cook
2016-07-18 8:26 ` [PATCH v3 00/11] mm: Hardened usercopy Balbir Singh
2016-07-20 9:52 ` David Laight
2016-07-20 15:31 ` Kees Cook
2016-07-20 16:02 ` David Laight
2016-07-20 16:22 ` Rik van Riel
2016-07-20 17:44 ` Kees Cook
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