From: Albert van der Linde <alinde@xxxxxxxxxx> 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: Albert van der Linde <alinde@xxxxxxxxxx> --- v2: - adressed comments from Dmitry Vyukov - removed failsize - changed should_fail function to return bool --- .../admin-guide/kernel-parameters.txt | 1 + .../fault-injection/fault-injection.rst | 7 +++- include/linux/fault-inject-usercopy.h | 22 +++++++++++ lib/Kconfig.debug | 7 ++++ lib/Makefile | 1 + lib/fault-inject-usercopy.c | 39 +++++++++++++++++++ 6 files changed, 76 insertions(+), 1 deletion(-) create mode 100644 include/linux/fault-inject-usercopy.h create mode 100644 lib/fault-inject-usercopy.c diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index a1068742a6df..790e54988d4f 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1332,6 +1332,7 @@ current integrity status. failslab= + fail_usercopy= fail_page_alloc= fail_make_request=[KNL] General fault injection mechanism. diff --git a/Documentation/fault-injection/fault-injection.rst b/Documentation/fault-injection/fault-injection.rst index f850ad018b70..31ecfe44e5b4 100644 --- a/Documentation/fault-injection/fault-injection.rst +++ b/Documentation/fault-injection/fault-injection.rst @@ -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); diff --git a/include/linux/fault-inject-usercopy.h b/include/linux/fault-inject-usercopy.h new file mode 100644 index 000000000000..56c3a693fdd9 --- /dev/null +++ b/include/linux/fault-inject-usercopy.h @@ -0,0 +1,22 @@ +/* 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__ */ diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index e068c3c7189a..2fc5049fba4e 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1770,6 +1770,13 @@ 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 diff --git a/lib/Makefile b/lib/Makefile index a4a4c6864f51..18daad2bc606 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -207,6 +207,7 @@ 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 diff --git a/lib/fault-inject-usercopy.c b/lib/fault-inject-usercopy.c new file mode 100644 index 000000000000..77558b6c29ca --- /dev/null +++ b/lib/fault-inject-usercopy.c @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <linux/fault-inject.h> +#include <linux/fault-inject-usercopy.h> + +static struct { + struct fault_attr attr; +} fail_usercopy = { + .attr = FAULT_ATTR_INITIALIZER, +}; + +static int __init setup_fail_usercopy(char *str) +{ + return setup_fault_attr(&fail_usercopy.attr, str); +} +__setup("fail_usercopy=", setup_fail_usercopy); + +#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS + +static int __init fail_usercopy_debugfs(void) +{ + struct dentry *dir; + + dir = fault_create_debugfs_attr("fail_usercopy", NULL, + &fail_usercopy.attr); + if (IS_ERR(dir)) + return PTR_ERR(dir); + + return 0; +} + +late_initcall(fail_usercopy_debugfs); + +#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */ + +bool should_fail_usercopy(void) +{ + return should_fail(&fail_usercopy.attr, 1); +} +EXPORT_SYMBOL_GPL(should_fail_usercopy); -- 2.28.0.402.g5ffc5be6b7-goog