linux-kernel - [PATCH v2 6/9] tty: n_gsm: increase malformed counter for malformed control frames

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Message-Id: <20230420085017.7314-6-daniel.starke@siemens.com>
Date:   Thu, 20 Apr 2023 10:50:14 +0200
From:   "D. Starke" <daniel.starke@...mens.com>
To:     linux-serial@...r.kernel.org, gregkh@...uxfoundation.org,
        jirislaby@...nel.org, ilpo.jarvinen@...ux.intel.com
Cc:     linux-kernel@...r.kernel.org,
        Daniel Starke <daniel.starke@...mens.com>
Subject: [PATCH v2 6/9] tty: n_gsm: increase malformed counter for malformed control frames

From: Daniel Starke <daniel.starke@...mens.com>

The malformed counter in gsm_mux is already increased in case of errors
detected in gsm_queue() and gsm1_receive(). gsm_dlci_command() also
detects a case for a malformed frame but does not increase the malformed
counter yet.

Fix this by also increasing the gsm_mux malformed counter in case of a
malformed frame in gsm_dlci_command().
Note that the malformed counter is not yet exposed and only set internally.

Signed-off-by: Daniel Starke <daniel.starke@...mens.com>
---
 drivers/tty/n_gsm.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

v1 -> v2:
Added remark to the commit message that the malformed counter is not yet
exposed to the user. This was remarked in the review.

Link: https://lore.kernel.org/all/AS4PR10MB589597931E257D7CACB984BCE0919@AS4PR10MB5895.EURPRD10.PROD.OUTLOOK.COM/

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 1e97a41e6be9..cc7be05c37ce 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2454,8 +2454,10 @@ static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
 	data += dlen;

 	/* Malformed command? */
-	if (clen > len)
+	if (clen > len) {
+		dlci->gsm->malformed++;
 		return;
+	}

 	if (command & 1)
 		gsm_control_message(dlci->gsm, command, data, clen);
-- 
2.34.1