diff options
| author | Daniel Starke <daniel.starke@siemens.com> | 2022-04-14 02:42:16 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-05-12 12:14:56 +0200 |
| commit | d194fae22b248f92fef85e7372f7f58d262f5b34 (patch) | |
| tree | 9c2578f634c09cf347a17b23fe258453b338dec3 | |
| parent | 5a503b98d09c3f96cc6644d639b0c012745b6500 (diff) | |
tty: n_gsm: fix wrong command retry handling
commit d0bcdffcad5a22f202e3bf37190c0dd8c080ea92 upstream.
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.aspx?specificationId=1516
The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to
the newer 27.010 here. Chapter 5.7.3 states that the valid range for the
maximum number of retransmissions (N2) is from 0 to 255 (both including).
gsm_config() fails to limit this range correctly. Furthermore,
gsm_control_retransmit() handles this number incorrectly by performing
N2 - 1 retransmission attempts. Setting N2 to zero results in more than 255
retransmission attempts.
Fix the range check in gsm_config() and the value handling in
gsm_control_send() and gsm_control_retransmit() to comply with 3GPP 27.010.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220414094225.4527-11-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/n_gsm.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index f02fe9a6593a..16547a50fedd 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1345,7 +1345,6 @@ static void gsm_control_retransmit(unsigned long data) spin_lock_irqsave(&gsm->control_lock, flags); ctrl = gsm->pending_cmd; if (ctrl) { - gsm->cretries--; if (gsm->cretries == 0) { gsm->pending_cmd = NULL; ctrl->error = -ETIMEDOUT; @@ -1354,6 +1353,7 @@ static void gsm_control_retransmit(unsigned long data) wake_up(&gsm->event); return; } + gsm->cretries--; gsm_control_transmit(gsm, ctrl); mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); } @@ -1394,7 +1394,7 @@ retry: /* If DLCI0 is in ADM mode skip retries, it won't respond */ if (gsm->dlci[0]->mode == DLCI_MODE_ADM) - gsm->cretries = 1; + gsm->cretries = 0; else gsm->cretries = gsm->n2; @@ -2519,7 +2519,7 @@ static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm, /* Check the MRU/MTU range looks sane */ if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8) return -EINVAL; - if (c->n2 < 3) + if (c->n2 > 255) return -EINVAL; if (c->encapsulation > 1) /* Basic, advanced, no I */ return -EINVAL; |