From: Andrew Morton <akpm@digeo.com>
To: Dave Jones <davej@codemonkey.org.uk>
Cc: linux-kernel@vger.kernel.org
Subject: Re: convert_fxsr_from_user
Date: Tue, 8 Apr 2003 16:51:13 -0700 [thread overview]
Message-ID: <20030408165113.3af2a32e.akpm@digeo.com> (raw)
In-Reply-To: <20030409001344.GA20353@suse.de>
Dave Jones <davej@codemonkey.org.uk> wrote:
>
> Andrew,
> A while back you optimised this routine to not do lots of memory
> copies. I've noticed it does no checking on the validity of the
> addresses it dereferences from userspace.
It never has performed those checks. The check is in the caller,
arch/i386/kernel/signal.c:restore_i387.
Bless you for merging Jon's uaccess.h documentation patch.
My __get_user()'s are arse-about.
diff -puN arch/i386/kernel/i387.c~convert_fxsr_from_user-get_user-fixes arch/i386/kernel/i387.c
--- 25/arch/i386/kernel/i387.c~convert_fxsr_from_user-get_user-fixes Tue Apr 8 16:47:08 2003
+++ 25-akpm/arch/i386/kernel/i387.c Tue Apr 8 16:48:13 2003
@@ -275,9 +275,9 @@ static int convert_fxsr_from_user( struc
unsigned long *t = (unsigned long *)to;
unsigned long *f = (unsigned long *)from;
- if (__get_user(*f, t) ||
- __get_user(*(f + 1), t + 1) ||
- __get_user(from->exponent, &to->exponent))
+ if (__get_user(*t, f) ||
+ __get_user(*(t + 1), f + 1) ||
+ __get_user(to->exponent, &from->exponent))
return 1;
}
return 0;
_
next prev parent reply other threads:[~2003-04-09 0:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-09 0:13 convert_fxsr_from_user Dave Jones
2003-04-08 23:51 ` Andrew Morton [this message]
2003-04-09 1:10 ` convert_fxsr_from_user Dave Jones
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