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Commit 7263dda4 authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

x86, smap: Handle csum_partial_copy_*_user() 



Add SMAP annotations to csum_partial_copy_to/from_user().  These
functions legitimately access user space and thus need to set the AC
flag.

TODO: add explicit checks that the side with the kernel space pointer
really points into kernel space.

Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/n/tip-2aps0u00eer658fd5xyanan7@git.kernel.org
Cc: <stable@vger.kernel.org> # v3.7+
parent d8dfad38

arch/x86/include/asm/checksum_32.h

+17 −5
Original line number Diff line number Diff line
@@ -49,9 +49,15 @@ static inline __wsum csum_partial_copy_from_user(const void __user *src, 
						 int len, __wsum sum,

						 int *err_ptr)

{

	__wsum ret;



	might_sleep();

	return csum_partial_copy_generic((__force void *)src, dst,

	stac();

	ret = csum_partial_copy_generic((__force void *)src, dst,

					len, sum, err_ptr, NULL);

	clac();



	return ret;

}



/*
@@ -176,10 +182,16 @@ static inline __wsum csum_and_copy_to_user(const void *src, 
					   int len, __wsum sum,

					   int *err_ptr)

{

	__wsum ret;



	might_sleep();

	if (access_ok(VERIFY_WRITE, dst, len))

		return csum_partial_copy_generic(src, (__force void *)dst,

	if (access_ok(VERIFY_WRITE, dst, len)) {

		stac();

		ret = csum_partial_copy_generic(src, (__force void *)dst,

						len, sum, NULL, err_ptr);

		clac();

		return ret;

	}



	if (len)

		*err_ptr = -EFAULT;

arch/x86/lib/csum-wrappers_64.c

+10 −2
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
 */

#include <asm/checksum.h>

#include <linux/module.h>

#include <asm/smap.h>



/**

 * csum_partial_copy_from_user - Copy and checksum from user space.
@@ -52,8 +53,10 @@ csum_partial_copy_from_user(const void __user *src, void *dst, 
			len -= 2;

		}

	}

	stac();

	isum = csum_partial_copy_generic((__force const void *)src,

				dst, len, isum, errp, NULL);

	clac();

	if (unlikely(*errp))

		goto out_err;
@@ -82,6 +85,8 @@ __wsum 
csum_partial_copy_to_user(const void *src, void __user *dst,

			  int len, __wsum isum, int *errp)

{

	__wsum ret;



	might_sleep();



	if (unlikely(!access_ok(VERIFY_WRITE, dst, len))) {
@@ -105,8 +110,11 @@ csum_partial_copy_to_user(const void *src, void __user *dst, 
	}



	*errp = 0;

	return csum_partial_copy_generic(src, (void __force *)dst,

	stac();

	ret = csum_partial_copy_generic(src, (void __force *)dst,

					len, isum, NULL, errp);

	clac();

	return ret;

}

EXPORT_SYMBOL(csum_partial_copy_to_user);