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x86: Add missing might_fault() checks to copy_{to,from}_user() 

On x86-64, copy_[to|from]_user() rely on assembly routines that
never call might_fault(), making us missing various lockdep
checks.

This doesn't apply to __copy_from,to_user() that explicitly
handle these calls, neither is it a problem in x86-32 where
copy_to,from_user() rely on the "__" prefixed versions that
also call might_fault().

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1258382538-30979-1-git-send-email-fweisbec@gmail.com>
[ v2: fix module export ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Frederic Weisbecker 2009-11-16 15:42:18 +01:00 committed by Ingo Molnar
parent 1472248583
commit 3c93ca00ee
3 changed files with 12 additions and 4 deletions
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10
arch/x86/include/asm/uaccess_64.h
View File

@ -19,7 +19,7 @@ __must_check unsigned long
copy_user_generic(void *to, const void *from, unsigned len);
__must_check unsigned long
copy_to_user(void __user *to, const void *from, unsigned len);
_copy_to_user(void __user *to, const void *from, unsigned len);
__must_check unsigned long
_copy_from_user(void *to, const void __user *from, unsigned len);
__must_check unsigned long
@ -32,6 +32,7 @@ static inline unsigned long __must_check copy_from_user(void *to,
int sz = __compiletime_object_size(to);
int ret = -EFAULT;
might_fault();
if (likely(sz == -1 || sz >= n))
ret = _copy_from_user(to, from, n);
#ifdef CONFIG_DEBUG_VM
@ -41,6 +42,13 @@ static inline unsigned long __must_check copy_from_user(void *to,
return ret;
}
static __always_inline __must_check
int copy_to_user(void __user *dst, const void *src, unsigned size)
{
might_fault();
return _copy_to_user(dst, src, size);
}
static __always_inline __must_check
int __copy_from_user(void *dst, const void __user *src, unsigned size)

2
arch/x86/kernel/x8664_ksyms_64.c
View File

@ -31,7 +31,7 @@ EXPORT_SYMBOL(__put_user_8);
EXPORT_SYMBOL(copy_user_generic);
EXPORT_SYMBOL(__copy_user_nocache);
EXPORT_SYMBOL(_copy_from_user);
EXPORT_SYMBOL(copy_to_user);
EXPORT_SYMBOL(_copy_to_user);
EXPORT_SYMBOL(copy_page);
EXPORT_SYMBOL(clear_page);

4
arch/x86/lib/copy_user_64.S
View File

@ -65,7 +65,7 @@
.endm
/* Standard copy_to_user with segment limit checking */
ENTRY(copy_to_user)
ENTRY(_copy_to_user)
CFI_STARTPROC
GET_THREAD_INFO(%rax)
movq %rdi,%rcx
@ -75,7 +75,7 @@ ENTRY(copy_to_user)
jae bad_to_user
ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,copy_user_generic_unrolled,copy_user_generic_string
CFI_ENDPROC
ENDPROC(copy_to_user)
ENDPROC(_copy_to_user)
/* Standard copy_from_user with segment limit checking */
ENTRY(_copy_from_user)