commit 14c328b46e23fcac4d9e2e38b989827e612e6d1e
author Christophe Leroy <christophe.leroy@c-s.fr> Fri Dec 14 15:26:20 2018 +0000
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> Sat Apr 20 09:07:53 2019 +0200
tree 30ddb8a74acfbb2a74d600b0a6811dddc9533d20
parent 52796ff1a545a6fe5d4a5504ae14b871134d0f76

lkdtm: Add tests for NULL pointer dereference

[ Upstream commit 59a12205d3c32aee4c13ca36889fdf7cfed31126 ]

Introduce lkdtm tests for NULL pointer dereference: check access or exec
at NULL address, since these errors tend to be reported differently from
the general fault error text. For example from x86:

    pr_alert("BUG: unable to handle kernel %s at %px\n",
        address < PAGE_SIZE ? "NULL pointer dereference" : "paging request",
        (void *)address);

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/misc/lkdtm.h

diff --git a/drivers/misc/lkdtm.h b/drivers/misc/lkdtm.h
index fdf954c..6abc97b 100644
--- a/drivers/misc/lkdtm.h
+++ b/drivers/misc/lkdtm.h
@@ -40,7 +40,9 @@
 void lkdtm_EXEC_VMALLOC(void);
 void lkdtm_EXEC_RODATA(void);
 void lkdtm_EXEC_USERSPACE(void);
+void lkdtm_EXEC_NULL(void);
 void lkdtm_ACCESS_USERSPACE(void);
+void lkdtm_ACCESS_NULL(void);
 
 /* lkdtm_rodata.c */
 void lkdtm_rodata_do_nothing(void);