lkml.org 
[lkml]   [2017]   [Dec]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.9 064/148] ARM: 8657/1: uaccess: consistently check object sizes
Date
4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Kees Cook <keescook@chromium.org>


[ Upstream commit 32b143637e8180f5d5cea54320c769210dea4f19 ]

In commit 76624175dcae ("arm64: uaccess: consistently check object sizes"),
the object size checks are moved outside the access_ok() so that bad
destinations are detected before hitting the "memset(dest, 0, size)" in the
copy_from_user() failure path.

This makes the same change for arm, with attention given to possibly
extracting the uaccess routines into a common header file for all
architectures in the future.

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/arm/include/asm/uaccess.h | 44 +++++++++++++++++++++++++++++------------
1 file changed, 32 insertions(+), 12 deletions(-)

--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -478,11 +478,10 @@ extern unsigned long __must_check
arm_copy_from_user(void *to, const void __user *from, unsigned long n);

static inline unsigned long __must_check
-__copy_from_user(void *to, const void __user *from, unsigned long n)
+__arch_copy_from_user(void *to, const void __user *from, unsigned long n)
{
unsigned int __ua_flags;

- check_object_size(to, n, false);
__ua_flags = uaccess_save_and_enable();
n = arm_copy_from_user(to, from, n);
uaccess_restore(__ua_flags);
@@ -495,18 +494,15 @@ extern unsigned long __must_check
__copy_to_user_std(void __user *to, const void *from, unsigned long n);

static inline unsigned long __must_check
-__copy_to_user(void __user *to, const void *from, unsigned long n)
+__arch_copy_to_user(void __user *to, const void *from, unsigned long n)
{
#ifndef CONFIG_UACCESS_WITH_MEMCPY
unsigned int __ua_flags;
-
- check_object_size(from, n, true);
__ua_flags = uaccess_save_and_enable();
n = arm_copy_to_user(to, from, n);
uaccess_restore(__ua_flags);
return n;
#else
- check_object_size(from, n, true);
return arm_copy_to_user(to, from, n);
#endif
}
@@ -526,25 +522,49 @@ __clear_user(void __user *addr, unsigned
}

#else
-#define __copy_from_user(to, from, n) (memcpy(to, (void __force *)from, n), 0)
-#define __copy_to_user(to, from, n) (memcpy((void __force *)to, from, n), 0)
+#define __arch_copy_from_user(to, from, n) \
+ (memcpy(to, (void __force *)from, n), 0)
+#define __arch_copy_to_user(to, from, n) \
+ (memcpy((void __force *)to, from, n), 0)
#define __clear_user(addr, n) (memset((void __force *)addr, 0, n), 0)
#endif

-static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
+static inline unsigned long __must_check
+__copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+ check_object_size(to, n, false);
+ return __arch_copy_from_user(to, from, n);
+}
+
+static inline unsigned long __must_check
+copy_from_user(void *to, const void __user *from, unsigned long n)
{
unsigned long res = n;
+
+ check_object_size(to, n, false);
+
if (likely(access_ok(VERIFY_READ, from, n)))
- res = __copy_from_user(to, from, n);
+ res = __arch_copy_from_user(to, from, n);
if (unlikely(res))
memset(to + (n - res), 0, res);
return res;
}

-static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
+static inline unsigned long __must_check
+__copy_to_user(void __user *to, const void *from, unsigned long n)
{
+ check_object_size(from, n, true);
+
+ return __arch_copy_to_user(to, from, n);
+}
+
+static inline unsigned long __must_check
+copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+ check_object_size(from, n, true);
+
if (access_ok(VERIFY_WRITE, to, n))
- n = __copy_to_user(to, from, n);
+ n = __arch_copy_to_user(to, from, n);
return n;
}


\
 
 \ /
  Last update: 2017-12-12 14:20    [W:0.407 / U:2.520 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site