[PATCH v1 09/10] lkdtm: Fix lkdtm_EXEC_RODATA()

Christophe Leroy
2021-10-11T15:25:36Z

Behind a location, lkdtm_EXEC_RODATA() executes a real function,
not a copy of do_nothing().

So do it directly instead of using execute_location().

And fix displayed addresses by dereferencing the function descriptors.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
drivers/misc/lkdtm/perms.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c
index 442d60ed25ef..da16564e1ecd 100644
--- a/drivers/misc/lkdtm/perms.c
+++ b/drivers/misc/lkdtm/perms.c
@@ -153,7 +153,14 @@ void lkdtm_EXEC_VMALLOC(void)

void lkdtm_EXEC_RODATA(void)
{
- execute_location(lkdtm_rodata_do_nothing, CODE_AS_IS);
+ pr_info("attempting ok execution at %px\n",
+ dereference_symbol_descriptor(do_nothing));
+ do_nothing();
+
+ pr_info("attempting bad execution at %px\n",
+ dereference_symbol_descriptor(lkdtm_rodata_do_nothing));
+ lkdtm_rodata_do_nothing();
+ pr_err("FAIL: func returned\n");
}

void lkdtm_EXEC_USERSPACE(void)
--
2.31.1