From b64913394f123e819bffabc79a0e48f98e78dc5d Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Tue, 15 Feb 2022 13:41:06 +0100 Subject: lkdtm: Really write into kernel text in WRITE_KERN WRITE_KERN is supposed to overwrite some kernel text, namely do_overwritten() function. But at the time being it overwrites do_overwritten() function descriptor, not function text. Fix it by dereferencing the function descriptor to obtain function text pointer. Export dereference_function_descriptor() for when LKDTM is built as a module. And make do_overwritten() noinline so that it is really do_overwritten() which is called by lkdtm_WRITE_KERN(). Signed-off-by: Christophe Leroy Acked-by: Kees Cook Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/31e58eaffb5bc51c07d8d4891d1982100ade8cfc.1644928018.git.christophe.leroy@csgroup.eu --- kernel/extable.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/extable.c') diff --git a/kernel/extable.c b/kernel/extable.c index 394c39b86e38..bda5e9761541 100644 --- a/kernel/extable.c +++ b/kernel/extable.c @@ -149,6 +149,7 @@ void *dereference_function_descriptor(void *ptr) ptr = p; return ptr; } +EXPORT_SYMBOL_GPL(dereference_function_descriptor); void *dereference_kernel_function_descriptor(void *ptr) { -- cgit v1.2.1