path: root/lib
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authorAlbert van der Linde <alinde@google.com>2020-10-15 20:13:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-16 11:11:22 -0700
commit2c739ced5886cd8c8361faa79a9522ec05174ed0 (patch)
tree6fb1604ea92b92f1300d1dc249e352cd3709ba7e /lib
parentd9bc85de46cad90851c346b592005090674b7669 (diff)
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: Albert van der Linde <alinde@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com> Reviewed-by: Alexander 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: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
3 files changed, 47 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 491789a793ae..ebe5ab111e65 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1768,6 +1768,13 @@ config FAIL_PAGE_ALLOC
Provide fault-injection capability for alloc_pages().
+ 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(), ...).
bool "Fault-injection capability for disk IO"
diff --git a/lib/Makefile b/lib/Makefile
index 49a2a9e36224..1c7577b2e86a 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -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
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 = {
+static int __init setup_fail_usercopy(char *str)
+ return setup_fault_attr(&fail_usercopy.attr, str);
+__setup("fail_usercopy=", setup_fail_usercopy);
+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;
+bool should_fail_usercopy(void)
+ return should_fail(&fail_usercopy.attr, 1);

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