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Commit c7588686 authored by Kees Cook's avatar Kees Cook
Browse files

lkdtm/usercopy: Adjust test to include an offset to check reporting 



Instead of doubling the size, push the start position up by 16 bytes to
still trigger an overflow. This allows to verify that offset reporting
is working correctly.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent f4e6e289

drivers/misc/lkdtm_usercopy.c

+9 −4
Original line number Diff line number Diff line
@@ -119,6 +119,8 @@ static void do_usercopy_heap_size(bool to_user) 
{

	unsigned long user_addr;

	unsigned char *one, *two;

	void __user *test_user_addr;

	void *test_kern_addr;

	size_t size = unconst + 1024;



	one = kmalloc(size, GFP_KERNEL);
@@ -139,27 +141,30 @@ static void do_usercopy_heap_size(bool to_user) 
	memset(one, 'A', size);

	memset(two, 'B', size);



	test_user_addr = (void __user *)(user_addr + 16);

	test_kern_addr = one + 16;



	if (to_user) {

		pr_info("attempting good copy_to_user of correct size\n");

		if (copy_to_user((void __user *)user_addr, one, size)) {

		if (copy_to_user(test_user_addr, test_kern_addr, size / 2)) {

			pr_warn("copy_to_user failed unexpectedly?!\n");

			goto free_user;

		}



		pr_info("attempting bad copy_to_user of too large size\n");

		if (copy_to_user((void __user *)user_addr, one, 2 * size)) {

		if (copy_to_user(test_user_addr, test_kern_addr, size)) {

			pr_warn("copy_to_user failed, but lacked Oops\n");

			goto free_user;

		}

	} else {

		pr_info("attempting good copy_from_user of correct size\n");

		if (copy_from_user(one, (void __user *)user_addr, size)) {

		if (copy_from_user(test_kern_addr, test_user_addr, size / 2)) {

			pr_warn("copy_from_user failed unexpectedly?!\n");

			goto free_user;

		}



		pr_info("attempting bad copy_from_user of too large size\n");

		if (copy_from_user(one, (void __user *)user_addr, 2 * size)) {

		if (copy_from_user(test_kern_addr, test_user_addr, size)) {

			pr_warn("copy_from_user failed, but lacked Oops\n");

			goto free_user;

		}