[PATCH v4 01/11] livepatch: Disallow vmlinux.ko

From: Josh Poimboeuf <jpoimboe@redhat.com>
To: live-patching@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Jessica Yu <jeyu@kernel.org>,
	Joe Lawrence <joe.lawrence@redhat.com>,
	Miroslav Benes <mbenes@suse.cz>
Subject: [PATCH v4 01/11] livepatch: Disallow vmlinux.ko
Date: Wed, 29 Apr 2020 10:24:43 -0500	[thread overview]
Message-ID: <3c23f9861a49662b7b3ee83b3bc17ebf9824e242.1588173720.git.jpoimboe@redhat.com> (raw)
In-Reply-To: <cover.1588173720.git.jpoimboe@redhat.com>

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 <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
---
 kernel/livepatch/core.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index c3512e7e0801..40cfac8156fd 100644
--- 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()
-- 
2.21.1

