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m68k: fix access_ok for coldfire

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commit 26509034be upstream.

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.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Arnd Bergmann 2022-02-15 17:59:41 +01:00 committed by Greg Kroah-Hartman
parent bed07e7ecc
commit b7509a4e81
1 changed files with 9 additions and 6 deletions
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15
arch/m68k/include/asm/uaccess.h
View file

@ -12,14 +12,17 @@
#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)
{
/*
* XXX: for !CONFIG_CPU_HAS_ADDRESS_SPACES this really needs to check
* for TASK_SIZE!
*/
return 1;
unsigned long limit = TASK_SIZE;
unsigned long addr = (unsigned long)ptr;
if (IS_ENABLED(CONFIG_CPU_HAS_ADDRESS_SPACES) ||
!IS_ENABLED(CONFIG_MMU))
return 1;
return (size <= limit) && (addr <= (limit - size));
}
/*