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Commit 4c5d7bc6 authored by Kees Cook's avatar Kees Cook
Browse files

usercopy: Add tests for all get_user() sizes 



The existing test was only exercising native unsigned long size
get_user(). For completeness, we should check all sizes. But we
must skip some 32-bit architectures that don't implement a 64-bit
get_user().

These new tests actually uncovered a bug in ARM's 64-bit get_user()
zeroing.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent f5f893c5

lib/test_user_copy.c

+76 −13
Original line number Diff line number Diff line
@@ -25,6 +25,23 @@ 
#include <linux/uaccess.h>

#include <linux/vmalloc.h>



/*

 * Several 32-bit architectures support 64-bit {get,put}_user() calls.

 * As there doesn't appear to be anything that can safely determine

 * their capability at compile-time, we just have to opt-out certain archs.

 */

#if BITS_PER_LONG == 64 || (!defined(CONFIG_AVR32)  &&		\

			    !defined(CONFIG_BLACKFIN) &&	\

			    !defined(CONFIG_M32R) &&		\

			    !defined(CONFIG_M68K) &&		\

			    !defined(CONFIG_MICROBLAZE) &&	\

			    !defined(CONFIG_MN10300) &&		\

			    !defined(CONFIG_NIOS2) &&		\

			    !defined(CONFIG_PPC32) &&		\

			    !defined(CONFIG_SUPERH))

# define TEST_U64

#endif



#define test(condition, msg)		\

({					\

	int cond = (condition);		\
@@ -40,7 +57,12 @@ static int __init test_user_copy_init(void) 
	char __user *usermem;

	char *bad_usermem;

	unsigned long user_addr;

	unsigned long value = 0x5A;

	u8 val_u8;

	u16 val_u16;

	u32 val_u32;

#ifdef TEST_U64

	u64 val_u64;

#endif



	kmem = kmalloc(PAGE_SIZE * 2, GFP_KERNEL);

	if (!kmem)
@@ -61,14 +83,39 @@ static int __init test_user_copy_init(void) 
	/*

	 * Legitimate usage: none of these copies should fail.

	 */

	ret |= test(copy_from_user(kmem, usermem, PAGE_SIZE),

		    "legitimate copy_from_user failed");

	memset(kmem, 0x3a, PAGE_SIZE * 2);

	ret |= test(copy_to_user(usermem, kmem, PAGE_SIZE),

		    "legitimate copy_to_user failed");

	ret |= test(get_user(value, (unsigned long __user *)usermem),

		    "legitimate get_user failed");

	ret |= test(put_user(value, (unsigned long __user *)usermem),

		    "legitimate put_user failed");

	memset(kmem, 0x0, PAGE_SIZE);

	ret |= test(copy_from_user(kmem, usermem, PAGE_SIZE),

		    "legitimate copy_from_user failed");

	ret |= test(memcmp(kmem, kmem + PAGE_SIZE, PAGE_SIZE),

		    "legitimate usercopy failed to copy data");



#define test_legit(size, check)						  \

	do {								  \

		val_##size = check;					  \

		ret |= test(put_user(val_##size, (size __user *)usermem), \

		    "legitimate put_user (" #size ") failed");		  \

		val_##size = 0;						  \

		ret |= test(get_user(val_##size, (size __user *)usermem), \

		    "legitimate get_user (" #size ") failed");		  \

		ret |= test(val_##size != check,			  \

		    "legitimate get_user (" #size ") failed to do copy"); \

		if (val_##size != check) {				  \

			pr_info("0x%llx != 0x%llx\n",			  \

				(unsigned long long)val_##size,		  \

				(unsigned long long)check);		  \

		}							  \

	} while (0)



	test_legit(u8,  0x5a);

	test_legit(u16, 0x5a5b);

	test_legit(u32, 0x5a5b5c5d);

#ifdef TEST_U64

	test_legit(u64, 0x5a5b5c5d6a6b6c6d);

#endif

#undef test_legit



	/*

	 * Invalid usage: none of these copies should succeed.
@@ -105,12 +152,28 @@ static int __init test_user_copy_init(void) 
				  PAGE_SIZE),

		    "illegal reversed copy_to_user passed");



	value = 0x5a;

	ret |= test(!get_user(value, (unsigned long __user *)kmem),

		    "illegal get_user passed");

	ret |= test(value != 0, "zeroing failure for illegal get_user");

	ret |= test(!put_user(value, (unsigned long __user *)kmem),

		    "illegal put_user passed");

#define test_illegal(size, check)					    \

	do {								    \

		val_##size = (check);					    \

		ret |= test(!get_user(val_##size, (size __user *)kmem),	    \

		    "illegal get_user (" #size ") passed");		    \

		ret |= test(val_##size != (size)0,			    \

		    "zeroing failure for illegal get_user (" #size ")");    \

		if (val_##size != (size)0) {				    \

			pr_info("0x%llx != 0\n",			    \

				(unsigned long long)val_##size);	    \

		}							    \

		ret |= test(!put_user(val_##size, (size __user *)kmem),	    \

		    "illegal put_user (" #size ") passed");		    \

	} while (0)



	test_illegal(u8,  0x5a);

	test_illegal(u16, 0x5a5b);

	test_illegal(u32, 0x5a5b5c5d);

#ifdef TEST_U64

	test_illegal(u64, 0x5a5b5c5d6a6b6c6d);

#endif

#undef test_illegal



	vm_munmap(user_addr, PAGE_SIZE * 2);

	kfree(kmem);