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From:   "Eric W. Biederman" <ebiederm@xmission.com>
To:     linux-kernel@vger.kernel.org
Cc:     David Miller <davem@davemloft.net>,
        Greg Kroah-Hartman <greg@kroah.com>,
        Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
        Alexei Starovoitov <alexei.starovoitov@gmail.com>,
        Kees Cook <keescook@chromium.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Al Viro <viro@zeniv.linux.org.uk>, bpf <bpf@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Gary Lin <GLin@suse.com>, Bruno Meneguele <bmeneg@redhat.com>,
        LSM List <linux-security-module@vger.kernel.org>,
        Casey Schaufler <casey@schaufler-ca.com>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Christian Brauner <christian.brauner@ubuntu.com>,
        "Eric W. Biederman" <ebiederm@xmission.com>
Date:   Thu,  2 Jul 2020 11:41:40 -0500
Message-Id: <20200702164140.4468-16-ebiederm@xmission.com>
In-Reply-To: <87y2o1swee.fsf_-_@x220.int.ebiederm.org>
References: <87y2o1swee.fsf_-_@x220.int.ebiederm.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Subject: [PATCH v3 16/16] umd: Stop using split_argv
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

There is exactly one argument so there is nothing to split.  All
split_argv does now is cause confusion and avoid the need for a cast
when passing a "const char *" string to call_usermodehelper_setup.

So avoid confusion and the possibility of an odd driver name causing
problems by just using a fixed argv array with a cast in the call to
call_usermodehelper_setup.

v1: https://lkml.kernel.org/r/87sged3a9n.fsf_-_@x220.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 kernel/usermode_driver.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/kernel/usermode_driver.c b/kernel/usermode_driver.c
index cd136f86f799..0b35212ffc3d 100644
--- a/kernel/usermode_driver.c
+++ b/kernel/usermode_driver.c
@@ -160,27 +160,21 @@ static void umd_cleanup(struct subprocess_info *info)
 int fork_usermode_driver(struct umd_info *info)
 {
 	struct subprocess_info *sub_info;
-	char **argv = NULL;
+	const char *argv[] = { info->driver_name, NULL };
 	int err;
 
 	if (WARN_ON_ONCE(info->tgid))
 		return -EBUSY;
 
 	err = -ENOMEM;
-	argv = argv_split(GFP_KERNEL, info->driver_name, NULL);
-	if (!argv)
-		goto out;
-
-	sub_info = call_usermodehelper_setup(info->driver_name, argv, NULL,
-					     GFP_KERNEL,
+	sub_info = call_usermodehelper_setup(info->driver_name,
+					     (char **)argv, NULL, GFP_KERNEL,
 					     umd_setup, umd_cleanup, info);
 	if (!sub_info)
 		goto out;
 
 	err = call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC);
 out:
-	if (argv)
-		argv_free(argv);
 	return err;
 }
 EXPORT_SYMBOL_GPL(fork_usermode_driver);
-- 
2.25.0