From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Arnd Bergmann <arnd@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Christoph Hellwig <hch@lst.de>,
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Subject: Re: [PATCH v2 10/18] m68k: fix access_ok for coldfire
Date: Fri, 18 Feb 2022 10:00:39 +0100 [thread overview]
Message-ID: <CAMuHMdWMhP5WgZ7CvOz53SyfizaAvLkHbeuds8G+_nZkwzhWWw@mail.gmail.com> (raw)
In-Reply-To: <20220216131332.1489939-11-arnd@kernel.org>
Hi Arnd,
On Wed, Feb 16, 2022 at 2:17 PM Arnd Bergmann <arnd@kernel.org> wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> While most m68k platforms use separate address spaces for user
> and kernel space, at least coldfire does not, and the other
> ones have a TASK_SIZE that is less than the entire 4GB address
> range.
>
> Using the default implementation of __access_ok() stops coldfire
> user space from trivially accessing kernel memory.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Thanks for your patch!
> --- a/arch/m68k/include/asm/uaccess.h
> +++ b/arch/m68k/include/asm/uaccess.h
> @@ -12,14 +12,21 @@
> #include <asm/extable.h>
>
> /* We let the MMU do all checking */
> -static inline int access_ok(const void __user *addr,
> +static inline int access_ok(const void __user *ptr,
> unsigned long size)
> {
> + unsigned long limit = TASK_SIZE;
> + unsigned long addr = (unsigned long)ptr;
> +
> /*
> * XXX: for !CONFIG_CPU_HAS_ADDRESS_SPACES this really needs to check
> * for TASK_SIZE!
> + * Removing this helper is probably sufficient.
> */
Shouldn't the above comment block be removed completely,
as this is now implemented below?
> - return 1;
> + if (IS_ENABLED(CONFIG_CPU_HAS_ADDRESS_SPACES))
> + return 1;
> +
> + return (size <= limit) && (addr <= (limit - size));
> }
Any pesky compilers that warn (or worse with -Werror) about
"condition always true" for TASK_SIZE = 0xFFFFFFFFUL?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2022-02-18 9:00 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-16 13:13 [PATCH v2 00/18] clean up asm/uaccess.h, kill set_fs for good Arnd Bergmann
2022-02-16 13:13 ` [PATCH v2 01/18] uaccess: fix integer overflow on access_ok() Arnd Bergmann
2022-02-16 13:13 ` [PATCH v2 02/18] uaccess: fix nios2 and microblaze get_user_8() Arnd Bergmann
2022-02-16 13:35 ` David Laight
2022-02-18 6:25 ` Christoph Hellwig
2022-02-25 4:28 ` Dinh Nguyen
2022-02-16 13:13 ` [PATCH v2 03/18] nds32: fix access_ok() checks in get/put_user Arnd Bergmann
2022-02-18 6:25 ` Christoph Hellwig
2022-02-16 13:13 ` [PATCH v2 04/18] sparc64: add __{get,put}_kernel_nocheck() Arnd Bergmann
2022-02-16 13:13 ` [PATCH v2 05/18] x86: remove __range_not_ok() Arnd Bergmann
2022-02-18 6:28 ` Christoph Hellwig
2022-02-18 7:29 ` Arnd Bergmann
2022-02-18 15:45 ` David Laight
2022-02-16 13:13 ` [PATCH v2 06/18] x86: use more conventional access_ok() definition Arnd Bergmann
2022-02-18 6:29 ` Christoph Hellwig
2022-02-16 13:13 ` [PATCH v2 07/18] nios2: drop access_ok() check from __put_user() Arnd Bergmann
2022-02-18 6:29 ` Christoph Hellwig
2022-02-23 23:30 ` Dinh Nguyen
2022-02-24 7:05 ` Arnd Bergmann
2022-02-16 13:13 ` [PATCH v2 08/18] uaccess: add generic __{get,put}_kernel_nofault Arnd Bergmann
2022-02-18 6:30 ` Christoph Hellwig
2022-02-18 8:55 ` Geert Uytterhoeven
2022-02-16 13:13 ` [PATCH v2 09/18] mips: use simpler access_ok() Arnd Bergmann
2022-02-21 13:24 ` Thomas Bogendoerfer
2022-02-21 14:31 ` Arnd Bergmann
2022-02-21 15:21 ` Thomas Bogendoerfer
2022-02-22 16:36 ` Thomas Bogendoerfer
2022-02-23 20:05 ` Linus Torvalds
2022-02-23 7:41 ` Thomas Bogendoerfer
2022-02-23 9:26 ` Arnd Bergmann
2022-02-16 13:13 ` [PATCH v2 10/18] m68k: fix access_ok for coldfire Arnd Bergmann
2022-02-18 6:30 ` Christoph Hellwig
2022-02-18 9:00 ` Geert Uytterhoeven [this message]
2022-02-18 9:24 ` Arnd Bergmann
2022-02-16 13:13 ` [PATCH v2 11/18] arm64: simplify access_ok() Arnd Bergmann
2022-02-16 13:13 ` [PATCH v2 12/18] uaccess: fix type mismatch warnings from access_ok() Arnd Bergmann
2022-02-18 6:31 ` Christoph Hellwig
2022-02-25 4:30 ` Dinh Nguyen
2022-02-16 13:13 ` [PATCH v2 13/18] uaccess: generalize access_ok() Arnd Bergmann
2022-02-17 7:52 ` Arnd Bergmann
2022-02-17 19:15 ` Andy Lutomirski
2022-02-18 7:16 ` Arnd Bergmann
2022-02-18 9:30 ` David Laight
2022-02-18 18:07 ` Andy Lutomirski
2022-02-18 6:34 ` Christoph Hellwig
2022-02-18 7:23 ` Arnd Bergmann
2022-02-18 9:04 ` Geert Uytterhoeven
2022-02-24 8:29 ` Stafford Horne
2022-02-24 8:41 ` Arnd Bergmann
2022-02-25 4:31 ` Dinh Nguyen
2022-02-16 13:13 ` [PATCH v2 14/18] lib/test_lockup: fix kernel pointer check for separate address spaces Arnd Bergmann
2022-02-18 6:35 ` Christoph Hellwig
2022-02-18 7:15 ` Arnd Bergmann
2022-02-16 13:13 ` [PATCH v2 15/18] sparc64: remove CONFIG_SET_FS support Arnd Bergmann
2022-02-16 18:34 ` Sam Ravnborg
2022-02-16 18:41 ` Sam Ravnborg
2022-02-16 22:01 ` Arnd Bergmann
2022-02-16 13:13 ` [PATCH v2 16/18] sh: " Arnd Bergmann
2022-02-18 6:36 ` Christoph Hellwig
2022-02-16 13:13 ` [PATCH v2 17/18] ia64: " Arnd Bergmann
2022-02-16 13:13 ` [PATCH v2 18/18] uaccess: drop maining CONFIG_SET_FS users Arnd Bergmann
2022-02-16 18:44 ` Sam Ravnborg
2022-02-16 22:02 ` Arnd Bergmann
2022-02-17 22:36 ` Eric W. Biederman
2022-02-18 6:37 ` Christoph Hellwig
2022-02-18 7:10 ` Arnd Bergmann
2022-02-24 8:45 ` Stafford Horne
2022-02-25 4:33 ` Dinh Nguyen
2022-02-17 7:20 ` [PATCH v2 00/18] clean up asm/uaccess.h, kill set_fs for good Christophe Leroy
2022-02-17 7:49 ` Arnd Bergmann
2022-02-18 2:21 ` Al Viro
2022-02-18 9:20 ` Arnd Bergmann
2022-02-18 1:50 ` Al Viro
2022-02-18 10:01 ` Christophe Leroy
2022-02-17 8:13 ` Arnd Bergmann
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