Commit 2c739ced authored by Albert van der Linde's avatar Albert van der Linde Committed by Linus Torvalds
Browse files

lib, include/linux: add usercopy failure capability 



Patch series "add fault injection to user memory access", v3.

The goal of this series is to improve testing of fault-tolerance in usages
of user memory access functions, by adding support for fault injection.

syzkaller/syzbot are using the existing fault injection modes and will use
this particular feature also.

The first patch adds failure injection capability for usercopy functions.
The second changes usercopy functions to use this new failure capability
(copy_from_user, ...).  The third patch adds get/put/clear_user failures
to x86.

This patch (of 3):

Add a failure injection capability to improve testing of fault-tolerance
in usages of user memory access functions.

Add CONFIG_FAULT_INJECTION_USERCOPY to enable faults in usercopy
functions.  The should_fail_usercopy function is to be called by these
functions (copy_from_user, get_user, ...) in order to fail or not.

Signed-off-by: default avatarAlbert van der Linde <alinde@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: default avatarAlexander Potapenko <glider@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20200831171733.955393-1-alinde@google.com
Link: http://lkml.kernel.org/r/20200831171733.955393-2-alinde@google.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d9bc85de

Documentation/admin-guide/kernel-parameters.txt

+1 −0
Original line number Diff line number Diff line
@@ -1343,6 +1343,7 @@ 
			current integrity status.



	failslab=

	fail_usercopy=

	fail_page_alloc=

	fail_make_request=[KNL]

			General fault injection mechanism.

Documentation/fault-injection/fault-injection.rst

+6 −1
Original line number Diff line number Diff line
@@ -16,6 +16,10 @@ Available fault injection capabilities 


  injects page allocation failures. (alloc_pages(), get_free_pages(), ...)



- fail_usercopy



  injects failures in user memory access functions. (copy_from_user(), get_user(), ...)



- fail_futex



  injects futex deadlock and uaddr fault errors.
@@ -177,6 +181,7 @@ use the boot option:: 


	failslab=

	fail_page_alloc=

	fail_usercopy=

	fail_make_request=

	fail_futex=

	mmc_core.fail_request=<interval>,<probability>,<space>,<times>
@@ -222,7 +227,7 @@ How to add new fault injection capability 


- debugfs entries



  failslab, fail_page_alloc, and fail_make_request use this way.

  failslab, fail_page_alloc, fail_usercopy, and fail_make_request use this way.

  Helper functions:



	fault_create_debugfs_attr(name, parent, attr);

include/linux/fault-inject-usercopy.h

0 → 100644
+22 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef __LINUX_FAULT_INJECT_USERCOPY_H__

#define __LINUX_FAULT_INJECT_USERCOPY_H__



/*

 * This header provides a wrapper for injecting failures to user space memory

 * access functions.

 */



#include <linux/types.h>



#ifdef CONFIG_FAULT_INJECTION_USERCOPY



bool should_fail_usercopy(void);



#else



static inline bool should_fail_usercopy(void) { return false; }



#endif /* CONFIG_FAULT_INJECTION_USERCOPY */



#endif /* __LINUX_FAULT_INJECT_USERCOPY_H__ */

lib/Kconfig.debug

+7 −0
Original line number Diff line number Diff line
@@ -1768,6 +1768,13 @@ config FAIL_PAGE_ALLOC 
	help

	  Provide fault-injection capability for alloc_pages().



config FAULT_INJECTION_USERCOPY

	bool "Fault injection capability for usercopy functions"

	depends on FAULT_INJECTION

	help

	  Provides fault-injection capability to inject failures

	  in usercopy functions (copy_from_user(), get_user(), ...).



config FAIL_MAKE_REQUEST

	bool "Fault-injection capability for disk IO"

	depends on FAULT_INJECTION && BLOCK

lib/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -210,6 +210,7 @@ obj-$(CONFIG_AUDIT_COMPAT_GENERIC) += compat_audit.o 


obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o

obj-$(CONFIG_FAULT_INJECTION) += fault-inject.o

obj-$(CONFIG_FAULT_INJECTION_USERCOPY) += fault-inject-usercopy.o

obj-$(CONFIG_NOTIFIER_ERROR_INJECTION) += notifier-error-inject.o

obj-$(CONFIG_PM_NOTIFIER_ERROR_INJECT) += pm-notifier-error-inject.o

obj-$(CONFIG_NETDEV_NOTIFIER_ERROR_INJECT) += netdev-notifier-error-inject.o

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