livepatch: Disallow vmlinux.ko

jpoimboe · Jiri Kosina · commit dcf550e52f56 · 2020-05-08T00:12:42.000+02:00
This is purely a theoretical issue, but if there were a module named
vmlinux.ko, the livepatch relocation code wouldn't be able to
distinguish between vmlinux-specific and vmlinux.o-specific KLP
relocations.

If CONFIG_LIVEPATCH is enabled, don't allow a module named vmlinux.ko.

Suggested-by: Peter Zijlstra &lt;peterz@infradead.org&gt;
Signed-off-by: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Acked-by: Miroslav Benes &lt;mbenes@suse.cz&gt;
Acked-by: Joe Lawrence &lt;joe.lawrence@redhat.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
@@ -1139,6 +1139,11 @@ int klp_module_coming(struct module *mod)
 	if (WARN_ON(mod->state != MODULE_STATE_COMING))
 		return -EINVAL;
 
+	if (!strcmp(mod->name, "vmlinux")) {
+		pr_err("vmlinux.ko: invalid module name");
+		return -EINVAL;
+	}
+
 	mutex_lock(&klp_mutex);
 	/*
 	 * Each module has to know that klp_module_coming()
