linux-kernel - [PATCH AUTOSEL 5.2 12/42] livepatch: Nullify obj->mod in klp_module

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190929173244.8918-12-sashal@kernel.org>
Date:   Sun, 29 Sep 2019 13:32:11 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Miroslav Benes <mbenes@...e.cz>, Petr Mladek <pmladek@...e.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Sasha Levin <sashal@...nel.org>, live-patching@...r.kernel.org
Subject: [PATCH AUTOSEL 5.2 12/42] livepatch: Nullify obj->mod in klp_module_coming()'s error path

From: Miroslav Benes <mbenes@...e.cz>

[ Upstream commit 4ff96fb52c6964ad42e0a878be8f86a2e8052ddd ]

klp_module_coming() is called for every module appearing in the system.
It sets obj->mod to a patched module for klp_object obj. Unfortunately
it leaves it set even if an error happens later in the function and the
patched module is not allowed to be loaded.

klp_is_object_loaded() uses obj->mod variable and could currently give a
wrong return value. The bug is probably harmless as of now.

Signed-off-by: Miroslav Benes <mbenes@...e.cz>
Reviewed-by: Petr Mladek <pmladek@...e.com>
Acked-by: Josh Poimboeuf <jpoimboe@...hat.com>
Signed-off-by: Petr Mladek <pmladek@...e.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 kernel/livepatch/core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index c4ce08f43bd63..ab4a4606d19b7 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -1175,6 +1175,7 @@ int klp_module_coming(struct module *mod)
 	pr_warn("patch '%s' failed for module '%s', refusing to load module '%s'\n",
 		patch->mod->name, obj->mod->name, obj->mod->name);
 	mod->klp_alive = false;
+	obj->mod = NULL;
 	klp_cleanup_module_patches_limited(mod, patch);
 	mutex_unlock(&klp_mutex);
 
-- 
2.20.1