test: check copy_to/from_user boundary validation
To help avoid an architecture failing to correctly check kernel/user
boundaries when handling copy_to_user, copy_from_user, put_user, or
get_user, perform some simple tests and fail to load if any of them
behave unexpectedly.
Specifically, this is to make sure there is a way to notice if things
like what was fixed in commit 8404663f81d2 ("ARM: 7527/1: uaccess:
explicitly check __user pointer when !CPU_USE_DOMAINS") ever regresses
again, for any architecture.
Additionally, adds new "user" selftest target, which loads this module.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 7e37a36..e0e2eeb 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1609,6 +1609,19 @@
If unsure, say N.
+config TEST_USER_COPY
+ tristate "Test user/kernel boundary protections"
+ default n
+ depends on m
+ help
+ This builds the "test_user_copy" module that runs sanity checks
+ on the copy_to/from_user infrastructure, making sure basic
+ user/kernel boundary testing is working. If it fails to load,
+ a regression has been detected in the user/kernel memory boundary
+ protections.
+
+ If unsure, say N.
+
source "samples/Kconfig"
source "lib/Kconfig.kgdb"
