Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 83a90bb1 authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Jiri Kosina
Browse files

livepatch: enforce patch stacking semantics 



Only allow the topmost patch on the stack to be enabled or disabled, so
that patches can't be removed or added in an arbitrary order.

Suggested-by: default avatarJiri Kosina <jkosina@suse.cz>
Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: default avatarJiri Slaby <jslaby@suse.cz>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent 32b7eb87

kernel/livepatch/core.c

+10 −0
Original line number Diff line number Diff line
@@ -379,6 +379,11 @@ static int __klp_disable_patch(struct klp_patch *patch) 
	struct klp_object *obj;

	int ret;



	/* enforce stacking: only the last enabled patch can be disabled */

	if (!list_is_last(&patch->list, &klp_patches) &&

	    list_next_entry(patch, list)->state == KLP_ENABLED)

		return -EBUSY;



	pr_notice("disabling patch '%s'\n", patch->mod->name);



	for (obj = patch->objs; obj->funcs; obj++) {
@@ -435,6 +440,11 @@ static int __klp_enable_patch(struct klp_patch *patch) 
	if (WARN_ON(patch->state != KLP_DISABLED))

		return -EINVAL;



	/* enforce stacking: only the first disabled patch can be enabled */

	if (patch->list.prev != &klp_patches &&

	    list_prev_entry(patch, list)->state == KLP_DISABLED)

		return -EBUSY;



	pr_notice_once("tainting kernel with TAINT_LIVEPATCH\n");

	add_taint(TAINT_LIVEPATCH, LOCKDEP_STILL_OK);