lkml.org 
[lkml]   [2019]   [Apr]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:x86/asm] x86/uaccess: Fix implicit cast of __user pointer
Commit-ID:  a6cbfbe6677efb5ca47bb7958c2718236c25126e
Gitweb: https://git.kernel.org/tip/a6cbfbe6677efb5ca47bb7958c2718236c25126e
Author: Jann Horn <jannh@google.com>
AuthorDate: Fri, 29 Mar 2019 22:46:52 +0100
Committer: Borislav Petkov <bp@suse.de>
CommitDate: Wed, 3 Apr 2019 16:26:17 +0200

x86/uaccess: Fix implicit cast of __user pointer

The first two arguments of __user_atomic_cmpxchg_inatomic() are:

- @uval is a kernel pointer into which the old value should be stored
- @ptr is the user pointer on which the cmpxchg should operate

This means that casting @uval to __typeof__(ptr) is wrong. Since @uval
is only used once inside the macro, just get rid of __uval and use
(uval) directly.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Qiaowei Ren <qiaowei.ren@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190329214652.258477-4-jannh@google.com
---
arch/x86/include/asm/uaccess.h | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 1954dd5552a2..a21f2a2f17bf 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -585,7 +585,6 @@ extern void __cmpxchg_wrong_size(void)
#define __user_atomic_cmpxchg_inatomic(uval, ptr, old, new, size) \
({ \
int __ret = 0; \
- __typeof__(ptr) __uval = (uval); \
__typeof__(*(ptr)) __old = (old); \
__typeof__(*(ptr)) __new = (new); \
__uaccess_begin_nospec(); \
@@ -661,7 +660,7 @@ extern void __cmpxchg_wrong_size(void)
__cmpxchg_wrong_size(); \
} \
__uaccess_end(); \
- *__uval = __old; \
+ *(uval) = __old; \
__ret; \
})

\
 
 \ /
  Last update: 2019-04-03 17:11    [W:0.083 / U:0.420 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site