Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 409d02ef authored by Heiko Carstens's avatar Heiko Carstens Committed by H. Peter Anvin
Browse files

x86: copy_from_user() should not return -EFAULT 



Callers of copy_from_user() expect it to return the number of bytes
it could not copy. In no case it is supposed to return -EFAULT.

In case of a detected buffer overflow just return the requested
length. In addition one could think of a memset that would clear
the size of the target object.

[ hpa: code is not in .32 so not needed for -stable ]

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: default avatarArjan van de Ven <arjan@linux.intel.com>
LKML-Reference: <20100105131911.GC5480@osiris.boeblingen.de.ibm.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent f4b825bd

arch/x86/include/asm/uaccess_32.h

+2 −3
Original line number Diff line number Diff line
@@ -205,14 +205,13 @@ static inline unsigned long __must_check copy_from_user(void *to, 
					  unsigned long n)

{

	int sz = __compiletime_object_size(to);

	int ret = -EFAULT;



	if (likely(sz == -1 || sz >= n))

		ret = _copy_from_user(to, from, n);

		n = _copy_from_user(to, from, n);

	else

		copy_from_user_overflow();



	return ret;

	return n;

}



long __must_check strncpy_from_user(char *dst, const char __user *src,

arch/x86/include/asm/uaccess_64.h

+2 −3
Original line number Diff line number Diff line
@@ -30,16 +30,15 @@ static inline unsigned long __must_check copy_from_user(void *to, 
					  unsigned long n)

{

	int sz = __compiletime_object_size(to);

	int ret = -EFAULT;



	might_fault();

	if (likely(sz == -1 || sz >= n))

		ret = _copy_from_user(to, from, n);

		n = _copy_from_user(to, from, n);

#ifdef CONFIG_DEBUG_VM

	else

		WARN(1, "Buffer overflow detected!\n");

#endif

	return ret;

	return n;

}



static __always_inline __must_check