From: Arnd Bergmann <arnd@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Christoph Hellwig <hch@lst.de>,
linux-arch@vger.kernel.org, linux-mm@kvack.org,
linux-api@vger.kernel.org, arnd@arndb.de,
linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
Cc: linux@armlinux.org.uk, will@kernel.org, guoren@kernel.org,
bcain@codeaurora.org, geert@linux-m68k.org, monstr@monstr.eu,
tsbogend@alpha.franken.de, nickhu@andestech.com,
green.hu@gmail.com, dinguyen@kernel.org, shorne@gmail.com,
deller@gmx.de, mpe@ellerman.id.au, peterz@infradead.org,
mingo@redhat.com, mark.rutland@arm.com, hca@linux.ibm.com,
dalias@libc.org, davem@davemloft.net, richard@nod.at,
x86@kernel.org, jcmvbkbc@gmail.com, ebiederm@xmission.com,
akpm@linux-foundation.org, ardb@kernel.org,
linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org,
linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org,
linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org,
linux-mips@vger.kernel.org, openrisc@lists.librecores.org,
linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org,
linux-sh@vger.kernel.org, sparclinux@vger.kernel.org,
linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org
Subject: [PATCH v2 06/18] x86: use more conventional access_ok() definition
Date: Wed, 16 Feb 2022 14:13:20 +0100 [thread overview]
Message-ID: <20220216131332.1489939-7-arnd@kernel.org> (raw)
In-Reply-To: <20220216131332.1489939-1-arnd@kernel.org>
From: Arnd Bergmann <arnd@arndb.de>
The way that access_ok() is defined on x86 is slightly different from
most other architectures, and a bit more complex.
The generic version tends to result in the best output on all
architectures, as it results in single comparison against a constant
limit for calls with a known size.
There are a few callers of __range_not_ok(), all of which use TASK_SIZE
as the limit rather than TASK_SIZE_MAX, but I could not see any reason
for picking this. Changing these to call __access_ok() instead uses the
default limit, but keeps the behavior otherwise.
x86 is the only architecture with a WARN_ON_IN_IRQ() checking
access_ok(), but it's probably best to leave that in place.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
arch/x86/include/asm/uaccess.h | 25 +++----------------------
1 file changed, 3 insertions(+), 22 deletions(-)
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 79c4869ccdd6..a59ba2578e64 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -16,33 +16,14 @@
* Test whether a block of memory is a valid user space address.
* Returns 0 if the range is valid, nonzero otherwise.
*/
-static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size)
+static inline bool __access_ok(void __user *ptr, unsigned long size)
{
unsigned long limit = TASK_SIZE_MAX;
+ unsigned long addr = ptr;
- /*
- * If we have used "sizeof()" for the size,
- * we know it won't overflow the limit (but
- * it might overflow the 'addr', so it's
- * important to subtract the size from the
- * limit, not add it to the address).
- */
- if (__builtin_constant_p(size))
- return unlikely(addr > limit - size);
-
- /* Arbitrary sizes? Be careful about overflow */
- addr += size;
- if (unlikely(addr < size))
- return true;
- return unlikely(addr > limit);
+ return (size <= limit) && (addr <= (limit - size));
}
-#define __access_ok(addr, size) \
-({ \
- __chk_user_ptr(addr); \
- !__chk_range_not_ok((unsigned long __force)(addr), size); \
-})
-
#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
static inline bool pagefault_disabled(void);
# define WARN_ON_IN_IRQ() \
--
2.29.2
next prev parent reply other threads:[~2022-02-16 13:16 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 ` Arnd Bergmann [this message]
2022-02-18 6:29 ` [PATCH v2 06/18] x86: use more conventional access_ok() definition 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
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
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=20220216131332.1489939-7-arnd@kernel.org \
--to=arnd@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=ardb@kernel.org \
--cc=arnd@arndb.de \
--cc=bcain@codeaurora.org \
--cc=dalias@libc.org \
--cc=davem@davemloft.net \
--cc=deller@gmx.de \
--cc=dinguyen@kernel.org \
--cc=ebiederm@xmission.com \
--cc=geert@linux-m68k.org \
--cc=green.hu@gmail.com \
--cc=guoren@kernel.org \
--cc=hca@linux.ibm.com \
--cc=hch@lst.de \
--cc=jcmvbkbc@gmail.com \
--cc=linux-alpha@vger.kernel.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-csky@vger.kernel.org \
--cc=linux-hexagon@vger.kernel.org \
--cc=linux-ia64@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-m68k@lists.linux-m68k.org \
--cc=linux-mips@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-parisc@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--cc=linux-s390@vger.kernel.org \
--cc=linux-sh@vger.kernel.org \
--cc=linux-snps-arc@lists.infradead.org \
--cc=linux-um@lists.infradead.org \
--cc=linux-xtensa@linux-xtensa.org \
--cc=linux@armlinux.org.uk \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mark.rutland@arm.com \
--cc=mingo@redhat.com \
--cc=monstr@monstr.eu \
--cc=mpe@ellerman.id.au \
--cc=nickhu@andestech.com \
--cc=openrisc@lists.librecores.org \
--cc=peterz@infradead.org \
--cc=richard@nod.at \
--cc=shorne@gmail.com \
--cc=sparclinux@vger.kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=tsbogend@alpha.franken.de \
--cc=viro@zeniv.linux.org.uk \
--cc=will@kernel.org \
--cc=x86@kernel.org \
/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).