Commit 888f84a6 authored by Alexander Potapenko's avatar Alexander Potapenko Committed by Andrew Morton
Browse files

x86: asm: instrument usercopy in get_user() and put_user() 

Use hooks from instrumented.h to notify bug detection tools about usercopy
events in variations of get_user() and put_user().

Link: https://lkml.kernel.org/r/20220915150417.722975-5-glider@google.com


Signed-off-by: default avatarAlexander Potapenko <glider@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 33b75c1d

arch/x86/include/asm/uaccess.h

+15 −7
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
 * User space memory access functions

 */

#include <linux/compiler.h>

#include <linux/instrumented.h>

#include <linux/kasan-checks.h>

#include <linux/string.h>

#include <asm/asm.h>
@@ -103,6 +104,7 @@ extern int __get_user_bad(void); 
		     : "=a" (__ret_gu), "=r" (__val_gu),		\

			ASM_CALL_CONSTRAINT				\

		     : "0" (ptr), "i" (sizeof(*(ptr))));		\

	instrument_get_user(__val_gu);					\

	(x) = (__force __typeof__(*(ptr))) __val_gu;			\

	__builtin_expect(__ret_gu, 0);					\

})
@@ -192,9 +194,11 @@ extern void __put_user_nocheck_8(void); 
	int __ret_pu;							\

	void __user *__ptr_pu;						\

	register __typeof__(*(ptr)) __val_pu asm("%"_ASM_AX);		\

	__chk_user_ptr(ptr);						\

	__ptr_pu = (ptr);						\

	__val_pu = (x);							\

	__typeof__(*(ptr)) __x = (x); /* eval x once */			\

	__typeof__(ptr) __ptr = (ptr); /* eval ptr once */		\

	__chk_user_ptr(__ptr);						\

	__ptr_pu = __ptr;						\

	__val_pu = __x;							\

	asm volatile("call __" #fn "_%P[size]"				\

		     : "=c" (__ret_pu),					\

			ASM_CALL_CONSTRAINT				\
@@ -202,6 +206,7 @@ extern void __put_user_nocheck_8(void); 
		       "r" (__val_pu),					\

		       [size] "i" (sizeof(*(ptr)))			\

		     :"ebx");						\

	instrument_put_user(__x, __ptr, sizeof(*(ptr)));		\

	__builtin_expect(__ret_pu, 0);					\

})
@@ -248,23 +253,25 @@ extern void __put_user_nocheck_8(void); 


#define __put_user_size(x, ptr, size, label)				\

do {									\

	__typeof__(*(ptr)) __x = (x); /* eval x once */			\

	__chk_user_ptr(ptr);						\

	switch (size) {							\

	case 1:								\

		__put_user_goto(x, ptr, "b", "iq", label);		\

		__put_user_goto(__x, ptr, "b", "iq", label);		\

		break;							\

	case 2:								\

		__put_user_goto(x, ptr, "w", "ir", label);		\

		__put_user_goto(__x, ptr, "w", "ir", label);		\

		break;							\

	case 4:								\

		__put_user_goto(x, ptr, "l", "ir", label);		\

		__put_user_goto(__x, ptr, "l", "ir", label);		\

		break;							\

	case 8:								\

		__put_user_goto_u64(x, ptr, label);			\

		__put_user_goto_u64(__x, ptr, label);			\

		break;							\

	default:							\

		__put_user_bad();					\

	}								\

	instrument_put_user(__x, ptr, size);				\

} while (0)



#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
@@ -305,6 +312,7 @@ do { \ 
	default:							\

		(x) = __get_user_bad();					\

	}								\

	instrument_get_user(x);						\

} while (0)



#define __get_user_asm(x, addr, itype, ltype, label)			\

include/linux/instrumented.h

+28 −0
Original line number Diff line number Diff line
@@ -153,4 +153,32 @@ instrument_copy_from_user_after(const void *to, const void __user *from, 
{

}



/**

 * instrument_get_user() - add instrumentation to get_user()-like macros

 *

 * get_user() and friends are fragile, so it may depend on the implementation

 * whether the instrumentation happens before or after the data is copied from

 * the userspace.

 *

 * @to destination variable, may not be address-taken

 */

#define instrument_get_user(to)                         \

({                                                      \

})



/**

 * instrument_put_user() - add instrumentation to put_user()-like macros

 *

 * put_user() and friends are fragile, so it may depend on the implementation

 * whether the instrumentation happens before or after the data is copied from

 * the userspace.

 *

 * @from source address

 * @ptr userspace pointer to copy to

 * @size number of bytes to copy

 */

#define instrument_put_user(from, ptr, size)                    \

({                                                              \

})



#endif /* _LINUX_INSTRUMENTED_H */