linux-arch.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Arnd Bergmann <arnd@arndb.de>
To: Mark Salter <msalter@redhat.com>
Cc: linux-arch@vger.kernel.org
Subject: Re: [PATCH] fix generic get_user and put_user
Date: Tue, 17 May 2011 22:26:53 +0200	[thread overview]
Message-ID: <201105172226.54517.arnd@arndb.de> (raw)
In-Reply-To: <1305657349-2783-1-git-send-email-msalter@redhat.com>

On Tuesday 17 May 2011, Mark Salter wrote:
> diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h
> index 1d0fdf8..5079335 100644
> --- a/include/asm-generic/uaccess.h
> +++ b/include/asm-generic/uaccess.h
> @@ -162,9 +162,10 @@ static inline __must_check long __copy_to_user(void __user *to,
>  
>  #define put_user(x, ptr)                                       \
>  ({                                                             \
> +       __typeof__(*(ptr)) *__pu_ptr = (ptr);                   \
>         might_sleep();                                          \
> -       access_ok(VERIFY_WRITE, ptr, sizeof(*ptr)) ?            \
> -               __put_user(x, ptr) :                            \
> +       access_ok(VERIFY_WRITE, __pu_ptr, sizeof(*ptr)) ?       \
> +               __put_user(x, __pu_ptr) :                       \
>                 -EFAULT;                                        \
>  })
>  
> @@ -218,9 +219,10 @@ extern int __put_user_bad(void) __attribute__((noreturn));
>  
>  #define get_user(x, ptr)                                       \
>  ({                                                             \
> +       __typeof__(*(ptr)) *__gu_ptr = (ptr);                   \
>         might_sleep();                                          \
> -       access_ok(VERIFY_READ, ptr, sizeof(*ptr)) ?             \
> -               __get_user(x, ptr) :                            \
> +       access_ok(VERIFY_READ, __gu_ptr, sizeof(*ptr)) ?        \
> +               __get_user(x, __gu_ptr) :                       \
>                 -EFAULT;                                        \
>  })
>  

IIRC, this doesn't work for get_user if the pointer is marked const.
Do you see a real problem with the current definitions, or are you
just trying to improve them genrally?

	Arnd

  reply	other threads:[~2011-05-17 20:26 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-17 18:35 [PATCH] fix generic get_user and put_user Mark Salter
2011-05-17 20:26 ` Arnd Bergmann [this message]
2011-05-17 21:25   ` Mark Salter

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=201105172226.54517.arnd@arndb.de \
    --to=arnd@arndb.de \
    --cc=linux-arch@vger.kernel.org \
    --cc=msalter@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).