From: Daniel Starke daniel.starke@siemens.com
[ Upstream commit 18a948c7d90995d127785e308fa7b701df4c499f ]
n_gsm is based on the 3GPP 07.010 and its newer version is the 3GPP 27.010. See https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.a... The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to the newer 27.010 here. Chapter 5.3.3 defines the DM response. There exists no DM command. However, the current implementation incorrectly sends DM as command in case of unexpected UIH frames in gsm_queue(). Correct this behavior by always sending DM as response.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Signed-off-by: Daniel Starke daniel.starke@siemens.com Link: https://lore.kernel.org/r/20220707113223.3685-2-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/n_gsm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index f4b5ac840222..39b6bcdc2c55 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1894,7 +1894,7 @@ static void gsm_queue(struct gsm_mux *gsm) goto invalid; #endif if (dlci == NULL || dlci->state != DLCI_OPEN) { - gsm_command(gsm, address, DM|PF); + gsm_response(gsm, address, DM|PF); return; } dlci->data(dlci, gsm->buf, gsm->len);