linux-kernel - [PATCH v2 1/9] livepatch: Disallow vmlinux.ko

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Message-Id: <68b2d27ce7991873ae3932e0f8f3f05c44dbc4f8.1587131959.git.jpoimboe@redhat.com>
Date:   Fri, 17 Apr 2020 09:04:26 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     live-patching@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Jessica Yu <jeyu@...nel.org>, Miroslav Benes <mbenes@...e.cz>
Subject: [PATCH v2 1/9] livepatch: Disallow vmlinux.ko

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@...radead.org>
Acked-by: Miroslav Benes <mbenes@...e.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.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