linux-kernel - [PATCH v2 2/2] tty/vt: prevent registration of console with invalid number

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Message-Id: <20221209112737.3222509-3-svens@linux.ibm.com>
Date:   Fri,  9 Dec 2022 12:27:37 +0100
From:   Sven Schnelle <svens@...ux.ibm.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jirislaby@...nel.org>
Cc:     Christian Borntraeger <borntraeger@...ibm.com>,
        linux-kernel@...r.kernel.org, linux-s390@...r.kernel.org
Subject: [PATCH v2 2/2] tty/vt: prevent registration of console with invalid number

If a user specifies an invalid console like 'console=tty3000',
the vt driver should prevent setting up a vt entry for that.

Suggested-by: Jiri Slaby <jirislaby@...nel.org>
Signed-off-by: Sven Schnelle <svens@...ux.ibm.com>
---
 drivers/tty/vt/vt.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 981d2bfcf9a5..62c8a45ad731 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -3156,8 +3156,14 @@ static struct tty_driver *vt_console_device(struct console *c, int *index)
 	return console_driver;
 }
 
+static int vt_console_setup(struct console *co, char *options)
+{
+	return co->index >= MAX_NR_CONSOLES ? -EINVAL : 0;
+}
+
 static struct console vt_console_driver = {
 	.name		= "tty",
+	.setup		= vt_console_setup,
 	.write		= vt_console_print,
 	.device		= vt_console_device,
 	.unblank	= unblank_screen,
-- 
2.34.1