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List:       live-patching
Subject:    [PATCH v3 01/10] livepatch: Disallow vmlinux.ko
From:       Josh Poimboeuf <jpoimboe () redhat ! com>
Date:       2020-04-25 11:07:21
Message-ID: 89ad8839664154577ea83fce7b758cb9bb6a7f22.1587812518.git.jpoimboe () redhat ! com
[Download RAW message or body]

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>
---
 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

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