To ensure we take the actual address of a function in kernel text, use
__va_function. Otherwise, with CONFIG_CFI_CLANG, the compiler replaces
the address with a pointer to the CFI jump table, which is actually in
the module when compiled with CONFIG_LKDTM=m.

Signed-off-by: Sami Tolvanen <samitolva...@google.com>
Acked-by: Kees Cook <keesc...@chromium.org>
---
 drivers/misc/lkdtm/usercopy.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c
index 109e8d4302c1..d173d6175c87 100644
--- a/drivers/misc/lkdtm/usercopy.c
+++ b/drivers/misc/lkdtm/usercopy.c
@@ -314,7 +314,7 @@ void lkdtm_USERCOPY_KERNEL(void)
 
        pr_info("attempting bad copy_to_user from kernel text: %px\n",
                vm_mmap);
-       if (copy_to_user((void __user *)user_addr, vm_mmap,
+       if (copy_to_user((void __user *)user_addr, __va_function(vm_mmap),
                         unconst + PAGE_SIZE)) {
                pr_warn("copy_to_user failed, but lacked Oops\n");
                goto free_user;
-- 
2.31.0.291.g576ba9dcdaf-goog

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