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Commit 4f80bcbe authored by Kees Cook's avatar Kees Cook Committed by Alex Shi
Browse files

x86/uaccess: Enable hardened usercopy 



Enables CONFIG_HARDENED_USERCOPY checks on x86. This is done both in
copy_*_user() and __copy_*_user() because copy_*_user() actually calls
down to _copy_*_user() and not __copy_*_user().

Based on code from PaX and grsecurity.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Tested-by: default avatarValdis Kletnieks <valdis.kletnieks@vt.edu>
(cherry picked from commit 5b710f34e194c6b7710f69fdb5d798fdf35b98c1)
Signed-off-by: default avatarAlex Shi <alex.shi@linaro.org>
parent 41a69b50

arch/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -77,6 +77,7 @@ config X86 
	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB

	select HAVE_AOUT			if X86_32

	select HAVE_ARCH_AUDITSYSCALL

	select HAVE_ARCH_HARDENED_USERCOPY

	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE

	select HAVE_ARCH_JUMP_LABEL

	select HAVE_ARCH_KASAN			if X86_64 && SPARSEMEM_VMEMMAP

arch/x86/include/asm/uaccess.h

+6 −4
Original line number Diff line number Diff line
@@ -731,9 +731,10 @@ copy_from_user(void *to, const void __user *from, unsigned long n) 
	 * case, and do only runtime checking for non-constant sizes.

	 */



	if (likely(sz < 0 || sz >= n))

	if (likely(sz < 0 || sz >= n)) {

		check_object_size(to, n, false);

		n = _copy_from_user(to, from, n);

	else if(__builtin_constant_p(n))

	} else if (__builtin_constant_p(n))

		copy_from_user_overflow();

	else

		__copy_from_user_overflow(sz, n);
@@ -749,9 +750,10 @@ copy_to_user(void __user *to, const void *from, unsigned long n) 
	might_fault();



	/* See the comment in copy_from_user() above. */

	if (likely(sz < 0 || sz >= n))

	if (likely(sz < 0 || sz >= n)) {

		check_object_size(from, n, true);

		n = _copy_to_user(to, from, n);

	else if(__builtin_constant_p(n))

	} else if (__builtin_constant_p(n))

		copy_to_user_overflow();

	else

		__copy_to_user_overflow(sz, n);

arch/x86/include/asm/uaccess_32.h

+2 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ unsigned long __must_check __copy_from_user_ll_nocache_nozero 
static __always_inline unsigned long __must_check

__copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)

{

	check_object_size(from, n, true);

	return __copy_to_user_ll(to, from, n);

}
@@ -95,6 +96,7 @@ static __always_inline unsigned long 
__copy_from_user(void *to, const void __user *from, unsigned long n)

{

	might_fault();

	check_object_size(to, n, false);

	if (__builtin_constant_p(n)) {

		unsigned long ret;

arch/x86/include/asm/uaccess_64.h

+2 −0
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ int __copy_from_user_nocheck(void *dst, const void __user *src, unsigned size) 
{

	int ret = 0;



	check_object_size(dst, size, false);

	if (!__builtin_constant_p(size))

		return copy_user_generic(dst, (__force void *)src, size);

	switch (size) {
@@ -117,6 +118,7 @@ int __copy_to_user_nocheck(void __user *dst, const void *src, unsigned size) 
{

	int ret = 0;



	check_object_size(src, size, true);

	if (!__builtin_constant_p(size))

		return copy_user_generic((__force void *)dst, src, size);

	switch (size) {