The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 7a0e4b1733b635026a87c023f6d703faf0095e39 Mon Sep 17 00:00:00 2001
From: Daniel Starke <daniel.starke(a)siemens.com>
Date: Thu, 14 Apr 2022 02:42:11 -0700
Subject: [PATCH] tty: n_gsm: fix frame reception handling
The frame checksum (FCS) is currently handled in gsm_queue() after
reception of a frame. However, this breaks layering. A workaround with
'received_fcs' was implemented so far.
Furthermore, frames are handled as such even if no end flag was received.
Move FCS calculation from gsm_queue() to gsm0_receive() and gsm1_receive().
Also delay gsm_queue() call there until a full frame was received to fix
both points.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
Cc: stable(a)vger.kernel.org
Signed-off-by: Daniel Starke <daniel.starke(a)siemens.com>
Link: https://lore.kernel.org/r/20220414094225.4527-6-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 3ba2505908e3..4ce18b42c37a 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -219,7 +219,6 @@ struct gsm_mux {
int encoding;
u8 control;
u8 fcs;
- u8 received_fcs;
u8 *txframe; /* TX framing buffer */
/* Method for the receiver side */
@@ -1794,18 +1793,7 @@ static void gsm_queue(struct gsm_mux *gsm)
u8 cr;
int address;
int i, j, k, address_tmp;
- /* We have to sneak a look at the packet body to do the FCS.
- A somewhat layering violation in the spec */
- if ((gsm->control & ~PF) == UI)
- gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
- if (gsm->encoding == 0) {
- /* WARNING: gsm->received_fcs is used for
- gsm->encoding = 0 only.
- In this case it contain the last piece of data
- required to generate final CRC */
- gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
- }
if (gsm->fcs != GOOD_FCS) {
gsm->bad_fcs++;
if (debug & 4)
@@ -1993,19 +1981,25 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
break;
case GSM_DATA: /* Data */
gsm->buf[gsm->count++] = c;
- if (gsm->count == gsm->len)
+ if (gsm->count == gsm->len) {
+ /* Calculate final FCS for UI frames over all data */
+ if ((gsm->control & ~PF) != UIH) {
+ gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
+ gsm->count);
+ }
gsm->state = GSM_FCS;
+ }
break;
case GSM_FCS: /* FCS follows the packet */
- gsm->received_fcs = c;
- gsm_queue(gsm);
+ gsm->fcs = gsm_fcs_add(gsm->fcs, c);
gsm->state = GSM_SSOF;
break;
case GSM_SSOF:
- if (c == GSM0_SOF) {
- gsm->state = GSM_SEARCH;
- break;
- }
+ gsm->state = GSM_SEARCH;
+ if (c == GSM0_SOF)
+ gsm_queue(gsm);
+ else
+ gsm->bad_size++;
break;
default:
pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
@@ -2024,11 +2018,24 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
{
if (c == GSM1_SOF) {
- /* EOF is only valid in frame if we have got to the data state
- and received at least one byte (the FCS) */
- if (gsm->state == GSM_DATA && gsm->count) {
- /* Extract the FCS */
+ /* EOF is only valid in frame if we have got to the data state */
+ if (gsm->state == GSM_DATA) {
+ if (gsm->count < 1) {
+ /* Missing FSC */
+ gsm->malformed++;
+ gsm->state = GSM_START;
+ return;
+ }
+ /* Remove the FCS from data */
gsm->count--;
+ if ((gsm->control & ~PF) != UIH) {
+ /* Calculate final FCS for UI frames over all
+ * data but FCS
+ */
+ gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
+ gsm->count);
+ }
+ /* Add the FCS itself to test against GOOD_FCS */
gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
gsm->len = gsm->count;
gsm_queue(gsm);
The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 7a0e4b1733b635026a87c023f6d703faf0095e39 Mon Sep 17 00:00:00 2001
From: Daniel Starke <daniel.starke(a)siemens.com>
Date: Thu, 14 Apr 2022 02:42:11 -0700
Subject: [PATCH] tty: n_gsm: fix frame reception handling
The frame checksum (FCS) is currently handled in gsm_queue() after
reception of a frame. However, this breaks layering. A workaround with
'received_fcs' was implemented so far.
Furthermore, frames are handled as such even if no end flag was received.
Move FCS calculation from gsm_queue() to gsm0_receive() and gsm1_receive().
Also delay gsm_queue() call there until a full frame was received to fix
both points.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
Cc: stable(a)vger.kernel.org
Signed-off-by: Daniel Starke <daniel.starke(a)siemens.com>
Link: https://lore.kernel.org/r/20220414094225.4527-6-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 3ba2505908e3..4ce18b42c37a 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -219,7 +219,6 @@ struct gsm_mux {
int encoding;
u8 control;
u8 fcs;
- u8 received_fcs;
u8 *txframe; /* TX framing buffer */
/* Method for the receiver side */
@@ -1794,18 +1793,7 @@ static void gsm_queue(struct gsm_mux *gsm)
u8 cr;
int address;
int i, j, k, address_tmp;
- /* We have to sneak a look at the packet body to do the FCS.
- A somewhat layering violation in the spec */
- if ((gsm->control & ~PF) == UI)
- gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
- if (gsm->encoding == 0) {
- /* WARNING: gsm->received_fcs is used for
- gsm->encoding = 0 only.
- In this case it contain the last piece of data
- required to generate final CRC */
- gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
- }
if (gsm->fcs != GOOD_FCS) {
gsm->bad_fcs++;
if (debug & 4)
@@ -1993,19 +1981,25 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
break;
case GSM_DATA: /* Data */
gsm->buf[gsm->count++] = c;
- if (gsm->count == gsm->len)
+ if (gsm->count == gsm->len) {
+ /* Calculate final FCS for UI frames over all data */
+ if ((gsm->control & ~PF) != UIH) {
+ gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
+ gsm->count);
+ }
gsm->state = GSM_FCS;
+ }
break;
case GSM_FCS: /* FCS follows the packet */
- gsm->received_fcs = c;
- gsm_queue(gsm);
+ gsm->fcs = gsm_fcs_add(gsm->fcs, c);
gsm->state = GSM_SSOF;
break;
case GSM_SSOF:
- if (c == GSM0_SOF) {
- gsm->state = GSM_SEARCH;
- break;
- }
+ gsm->state = GSM_SEARCH;
+ if (c == GSM0_SOF)
+ gsm_queue(gsm);
+ else
+ gsm->bad_size++;
break;
default:
pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
@@ -2024,11 +2018,24 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
{
if (c == GSM1_SOF) {
- /* EOF is only valid in frame if we have got to the data state
- and received at least one byte (the FCS) */
- if (gsm->state == GSM_DATA && gsm->count) {
- /* Extract the FCS */
+ /* EOF is only valid in frame if we have got to the data state */
+ if (gsm->state == GSM_DATA) {
+ if (gsm->count < 1) {
+ /* Missing FSC */
+ gsm->malformed++;
+ gsm->state = GSM_START;
+ return;
+ }
+ /* Remove the FCS from data */
gsm->count--;
+ if ((gsm->control & ~PF) != UIH) {
+ /* Calculate final FCS for UI frames over all
+ * data but FCS
+ */
+ gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
+ gsm->count);
+ }
+ /* Add the FCS itself to test against GOOD_FCS */
gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
gsm->len = gsm->count;
gsm_queue(gsm);
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 7a0e4b1733b635026a87c023f6d703faf0095e39 Mon Sep 17 00:00:00 2001
From: Daniel Starke <daniel.starke(a)siemens.com>
Date: Thu, 14 Apr 2022 02:42:11 -0700
Subject: [PATCH] tty: n_gsm: fix frame reception handling
The frame checksum (FCS) is currently handled in gsm_queue() after
reception of a frame. However, this breaks layering. A workaround with
'received_fcs' was implemented so far.
Furthermore, frames are handled as such even if no end flag was received.
Move FCS calculation from gsm_queue() to gsm0_receive() and gsm1_receive().
Also delay gsm_queue() call there until a full frame was received to fix
both points.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
Cc: stable(a)vger.kernel.org
Signed-off-by: Daniel Starke <daniel.starke(a)siemens.com>
Link: https://lore.kernel.org/r/20220414094225.4527-6-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 3ba2505908e3..4ce18b42c37a 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -219,7 +219,6 @@ struct gsm_mux {
int encoding;
u8 control;
u8 fcs;
- u8 received_fcs;
u8 *txframe; /* TX framing buffer */
/* Method for the receiver side */
@@ -1794,18 +1793,7 @@ static void gsm_queue(struct gsm_mux *gsm)
u8 cr;
int address;
int i, j, k, address_tmp;
- /* We have to sneak a look at the packet body to do the FCS.
- A somewhat layering violation in the spec */
- if ((gsm->control & ~PF) == UI)
- gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
- if (gsm->encoding == 0) {
- /* WARNING: gsm->received_fcs is used for
- gsm->encoding = 0 only.
- In this case it contain the last piece of data
- required to generate final CRC */
- gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
- }
if (gsm->fcs != GOOD_FCS) {
gsm->bad_fcs++;
if (debug & 4)
@@ -1993,19 +1981,25 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
break;
case GSM_DATA: /* Data */
gsm->buf[gsm->count++] = c;
- if (gsm->count == gsm->len)
+ if (gsm->count == gsm->len) {
+ /* Calculate final FCS for UI frames over all data */
+ if ((gsm->control & ~PF) != UIH) {
+ gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
+ gsm->count);
+ }
gsm->state = GSM_FCS;
+ }
break;
case GSM_FCS: /* FCS follows the packet */
- gsm->received_fcs = c;
- gsm_queue(gsm);
+ gsm->fcs = gsm_fcs_add(gsm->fcs, c);
gsm->state = GSM_SSOF;
break;
case GSM_SSOF:
- if (c == GSM0_SOF) {
- gsm->state = GSM_SEARCH;
- break;
- }
+ gsm->state = GSM_SEARCH;
+ if (c == GSM0_SOF)
+ gsm_queue(gsm);
+ else
+ gsm->bad_size++;
break;
default:
pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
@@ -2024,11 +2018,24 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
{
if (c == GSM1_SOF) {
- /* EOF is only valid in frame if we have got to the data state
- and received at least one byte (the FCS) */
- if (gsm->state == GSM_DATA && gsm->count) {
- /* Extract the FCS */
+ /* EOF is only valid in frame if we have got to the data state */
+ if (gsm->state == GSM_DATA) {
+ if (gsm->count < 1) {
+ /* Missing FSC */
+ gsm->malformed++;
+ gsm->state = GSM_START;
+ return;
+ }
+ /* Remove the FCS from data */
gsm->count--;
+ if ((gsm->control & ~PF) != UIH) {
+ /* Calculate final FCS for UI frames over all
+ * data but FCS
+ */
+ gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
+ gsm->count);
+ }
+ /* Add the FCS itself to test against GOOD_FCS */
gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
gsm->len = gsm->count;
gsm_queue(gsm);
The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 7a0e4b1733b635026a87c023f6d703faf0095e39 Mon Sep 17 00:00:00 2001
From: Daniel Starke <daniel.starke(a)siemens.com>
Date: Thu, 14 Apr 2022 02:42:11 -0700
Subject: [PATCH] tty: n_gsm: fix frame reception handling
The frame checksum (FCS) is currently handled in gsm_queue() after
reception of a frame. However, this breaks layering. A workaround with
'received_fcs' was implemented so far.
Furthermore, frames are handled as such even if no end flag was received.
Move FCS calculation from gsm_queue() to gsm0_receive() and gsm1_receive().
Also delay gsm_queue() call there until a full frame was received to fix
both points.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
Cc: stable(a)vger.kernel.org
Signed-off-by: Daniel Starke <daniel.starke(a)siemens.com>
Link: https://lore.kernel.org/r/20220414094225.4527-6-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 3ba2505908e3..4ce18b42c37a 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -219,7 +219,6 @@ struct gsm_mux {
int encoding;
u8 control;
u8 fcs;
- u8 received_fcs;
u8 *txframe; /* TX framing buffer */
/* Method for the receiver side */
@@ -1794,18 +1793,7 @@ static void gsm_queue(struct gsm_mux *gsm)
u8 cr;
int address;
int i, j, k, address_tmp;
- /* We have to sneak a look at the packet body to do the FCS.
- A somewhat layering violation in the spec */
- if ((gsm->control & ~PF) == UI)
- gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
- if (gsm->encoding == 0) {
- /* WARNING: gsm->received_fcs is used for
- gsm->encoding = 0 only.
- In this case it contain the last piece of data
- required to generate final CRC */
- gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
- }
if (gsm->fcs != GOOD_FCS) {
gsm->bad_fcs++;
if (debug & 4)
@@ -1993,19 +1981,25 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
break;
case GSM_DATA: /* Data */
gsm->buf[gsm->count++] = c;
- if (gsm->count == gsm->len)
+ if (gsm->count == gsm->len) {
+ /* Calculate final FCS for UI frames over all data */
+ if ((gsm->control & ~PF) != UIH) {
+ gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
+ gsm->count);
+ }
gsm->state = GSM_FCS;
+ }
break;
case GSM_FCS: /* FCS follows the packet */
- gsm->received_fcs = c;
- gsm_queue(gsm);
+ gsm->fcs = gsm_fcs_add(gsm->fcs, c);
gsm->state = GSM_SSOF;
break;
case GSM_SSOF:
- if (c == GSM0_SOF) {
- gsm->state = GSM_SEARCH;
- break;
- }
+ gsm->state = GSM_SEARCH;
+ if (c == GSM0_SOF)
+ gsm_queue(gsm);
+ else
+ gsm->bad_size++;
break;
default:
pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
@@ -2024,11 +2018,24 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
{
if (c == GSM1_SOF) {
- /* EOF is only valid in frame if we have got to the data state
- and received at least one byte (the FCS) */
- if (gsm->state == GSM_DATA && gsm->count) {
- /* Extract the FCS */
+ /* EOF is only valid in frame if we have got to the data state */
+ if (gsm->state == GSM_DATA) {
+ if (gsm->count < 1) {
+ /* Missing FSC */
+ gsm->malformed++;
+ gsm->state = GSM_START;
+ return;
+ }
+ /* Remove the FCS from data */
gsm->count--;
+ if ((gsm->control & ~PF) != UIH) {
+ /* Calculate final FCS for UI frames over all
+ * data but FCS
+ */
+ gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
+ gsm->count);
+ }
+ /* Add the FCS itself to test against GOOD_FCS */
gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
gsm->len = gsm->count;
gsm_queue(gsm);
The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 7a0e4b1733b635026a87c023f6d703faf0095e39 Mon Sep 17 00:00:00 2001
From: Daniel Starke <daniel.starke(a)siemens.com>
Date: Thu, 14 Apr 2022 02:42:11 -0700
Subject: [PATCH] tty: n_gsm: fix frame reception handling
The frame checksum (FCS) is currently handled in gsm_queue() after
reception of a frame. However, this breaks layering. A workaround with
'received_fcs' was implemented so far.
Furthermore, frames are handled as such even if no end flag was received.
Move FCS calculation from gsm_queue() to gsm0_receive() and gsm1_receive().
Also delay gsm_queue() call there until a full frame was received to fix
both points.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
Cc: stable(a)vger.kernel.org
Signed-off-by: Daniel Starke <daniel.starke(a)siemens.com>
Link: https://lore.kernel.org/r/20220414094225.4527-6-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 3ba2505908e3..4ce18b42c37a 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -219,7 +219,6 @@ struct gsm_mux {
int encoding;
u8 control;
u8 fcs;
- u8 received_fcs;
u8 *txframe; /* TX framing buffer */
/* Method for the receiver side */
@@ -1794,18 +1793,7 @@ static void gsm_queue(struct gsm_mux *gsm)
u8 cr;
int address;
int i, j, k, address_tmp;
- /* We have to sneak a look at the packet body to do the FCS.
- A somewhat layering violation in the spec */
- if ((gsm->control & ~PF) == UI)
- gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
- if (gsm->encoding == 0) {
- /* WARNING: gsm->received_fcs is used for
- gsm->encoding = 0 only.
- In this case it contain the last piece of data
- required to generate final CRC */
- gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
- }
if (gsm->fcs != GOOD_FCS) {
gsm->bad_fcs++;
if (debug & 4)
@@ -1993,19 +1981,25 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
break;
case GSM_DATA: /* Data */
gsm->buf[gsm->count++] = c;
- if (gsm->count == gsm->len)
+ if (gsm->count == gsm->len) {
+ /* Calculate final FCS for UI frames over all data */
+ if ((gsm->control & ~PF) != UIH) {
+ gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
+ gsm->count);
+ }
gsm->state = GSM_FCS;
+ }
break;
case GSM_FCS: /* FCS follows the packet */
- gsm->received_fcs = c;
- gsm_queue(gsm);
+ gsm->fcs = gsm_fcs_add(gsm->fcs, c);
gsm->state = GSM_SSOF;
break;
case GSM_SSOF:
- if (c == GSM0_SOF) {
- gsm->state = GSM_SEARCH;
- break;
- }
+ gsm->state = GSM_SEARCH;
+ if (c == GSM0_SOF)
+ gsm_queue(gsm);
+ else
+ gsm->bad_size++;
break;
default:
pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
@@ -2024,11 +2018,24 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
{
if (c == GSM1_SOF) {
- /* EOF is only valid in frame if we have got to the data state
- and received at least one byte (the FCS) */
- if (gsm->state == GSM_DATA && gsm->count) {
- /* Extract the FCS */
+ /* EOF is only valid in frame if we have got to the data state */
+ if (gsm->state == GSM_DATA) {
+ if (gsm->count < 1) {
+ /* Missing FSC */
+ gsm->malformed++;
+ gsm->state = GSM_START;
+ return;
+ }
+ /* Remove the FCS from data */
gsm->count--;
+ if ((gsm->control & ~PF) != UIH) {
+ /* Calculate final FCS for UI frames over all
+ * data but FCS
+ */
+ gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
+ gsm->count);
+ }
+ /* Add the FCS itself to test against GOOD_FCS */
gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
gsm->len = gsm->count;
gsm_queue(gsm);
The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 284260f278b706364fb4c88a7b56ba5298d5973c Mon Sep 17 00:00:00 2001
From: Daniel Starke <daniel.starke(a)siemens.com>
Date: Thu, 14 Apr 2022 02:42:09 -0700
Subject: [PATCH] tty: n_gsm: fix mux cleanup after unregister tty device
Internally, we manage the alive state of the mux channels and mux itself
with the field member 'dead'. This makes it possible to notify the user
if the accessed underlying link is already gone. On the other hand,
however, removing the virtual ttys before terminating the channels may
result in peer messages being received without any internal target. Move
the mux cleanup procedure from gsmld_detach_gsm() to gsmld_close() to fix
this by keeping the virtual ttys open until the mux has been cleaned up.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
Cc: stable(a)vger.kernel.org
Signed-off-by: Daniel Starke <daniel.starke(a)siemens.com>
Link: https://lore.kernel.org/r/20220414094225.4527-4-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index f546dfe03d29..de97a3810731 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2479,7 +2479,6 @@ static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
for (i = 1; i < NUM_DLCI; i++)
tty_unregister_device(gsm_tty_driver, base + i);
}
- gsm_cleanup_mux(gsm, false);
tty_kref_put(gsm->tty);
gsm->tty = NULL;
}
@@ -2544,6 +2543,12 @@ static void gsmld_close(struct tty_struct *tty)
{
struct gsm_mux *gsm = tty->disc_data;
+ /* The ldisc locks and closes the port before calling our close. This
+ * means we have no way to do a proper disconnect. We will not bother
+ * to do one.
+ */
+ gsm_cleanup_mux(gsm, false);
+
gsmld_detach_gsm(tty, gsm);
gsmld_flush_buffer(tty);
The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 284260f278b706364fb4c88a7b56ba5298d5973c Mon Sep 17 00:00:00 2001
From: Daniel Starke <daniel.starke(a)siemens.com>
Date: Thu, 14 Apr 2022 02:42:09 -0700
Subject: [PATCH] tty: n_gsm: fix mux cleanup after unregister tty device
Internally, we manage the alive state of the mux channels and mux itself
with the field member 'dead'. This makes it possible to notify the user
if the accessed underlying link is already gone. On the other hand,
however, removing the virtual ttys before terminating the channels may
result in peer messages being received without any internal target. Move
the mux cleanup procedure from gsmld_detach_gsm() to gsmld_close() to fix
this by keeping the virtual ttys open until the mux has been cleaned up.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
Cc: stable(a)vger.kernel.org
Signed-off-by: Daniel Starke <daniel.starke(a)siemens.com>
Link: https://lore.kernel.org/r/20220414094225.4527-4-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index f546dfe03d29..de97a3810731 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2479,7 +2479,6 @@ static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
for (i = 1; i < NUM_DLCI; i++)
tty_unregister_device(gsm_tty_driver, base + i);
}
- gsm_cleanup_mux(gsm, false);
tty_kref_put(gsm->tty);
gsm->tty = NULL;
}
@@ -2544,6 +2543,12 @@ static void gsmld_close(struct tty_struct *tty)
{
struct gsm_mux *gsm = tty->disc_data;
+ /* The ldisc locks and closes the port before calling our close. This
+ * means we have no way to do a proper disconnect. We will not bother
+ * to do one.
+ */
+ gsm_cleanup_mux(gsm, false);
+
gsmld_detach_gsm(tty, gsm);
gsmld_flush_buffer(tty);
The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 284260f278b706364fb4c88a7b56ba5298d5973c Mon Sep 17 00:00:00 2001
From: Daniel Starke <daniel.starke(a)siemens.com>
Date: Thu, 14 Apr 2022 02:42:09 -0700
Subject: [PATCH] tty: n_gsm: fix mux cleanup after unregister tty device
Internally, we manage the alive state of the mux channels and mux itself
with the field member 'dead'. This makes it possible to notify the user
if the accessed underlying link is already gone. On the other hand,
however, removing the virtual ttys before terminating the channels may
result in peer messages being received without any internal target. Move
the mux cleanup procedure from gsmld_detach_gsm() to gsmld_close() to fix
this by keeping the virtual ttys open until the mux has been cleaned up.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
Cc: stable(a)vger.kernel.org
Signed-off-by: Daniel Starke <daniel.starke(a)siemens.com>
Link: https://lore.kernel.org/r/20220414094225.4527-4-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index f546dfe03d29..de97a3810731 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2479,7 +2479,6 @@ static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
for (i = 1; i < NUM_DLCI; i++)
tty_unregister_device(gsm_tty_driver, base + i);
}
- gsm_cleanup_mux(gsm, false);
tty_kref_put(gsm->tty);
gsm->tty = NULL;
}
@@ -2544,6 +2543,12 @@ static void gsmld_close(struct tty_struct *tty)
{
struct gsm_mux *gsm = tty->disc_data;
+ /* The ldisc locks and closes the port before calling our close. This
+ * means we have no way to do a proper disconnect. We will not bother
+ * to do one.
+ */
+ gsm_cleanup_mux(gsm, false);
+
gsmld_detach_gsm(tty, gsm);
gsmld_flush_buffer(tty);
The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 284260f278b706364fb4c88a7b56ba5298d5973c Mon Sep 17 00:00:00 2001
From: Daniel Starke <daniel.starke(a)siemens.com>
Date: Thu, 14 Apr 2022 02:42:09 -0700
Subject: [PATCH] tty: n_gsm: fix mux cleanup after unregister tty device
Internally, we manage the alive state of the mux channels and mux itself
with the field member 'dead'. This makes it possible to notify the user
if the accessed underlying link is already gone. On the other hand,
however, removing the virtual ttys before terminating the channels may
result in peer messages being received without any internal target. Move
the mux cleanup procedure from gsmld_detach_gsm() to gsmld_close() to fix
this by keeping the virtual ttys open until the mux has been cleaned up.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
Cc: stable(a)vger.kernel.org
Signed-off-by: Daniel Starke <daniel.starke(a)siemens.com>
Link: https://lore.kernel.org/r/20220414094225.4527-4-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index f546dfe03d29..de97a3810731 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2479,7 +2479,6 @@ static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
for (i = 1; i < NUM_DLCI; i++)
tty_unregister_device(gsm_tty_driver, base + i);
}
- gsm_cleanup_mux(gsm, false);
tty_kref_put(gsm->tty);
gsm->tty = NULL;
}
@@ -2544,6 +2543,12 @@ static void gsmld_close(struct tty_struct *tty)
{
struct gsm_mux *gsm = tty->disc_data;
+ /* The ldisc locks and closes the port before calling our close. This
+ * means we have no way to do a proper disconnect. We will not bother
+ * to do one.
+ */
+ gsm_cleanup_mux(gsm, false);
+
gsmld_detach_gsm(tty, gsm);
gsmld_flush_buffer(tty);
The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 1ec92e9742774bf42614fceea3bf6b50c9409225 Mon Sep 17 00:00:00 2001
From: Daniel Starke <daniel.starke(a)siemens.com>
Date: Thu, 14 Apr 2022 02:42:08 -0700
Subject: [PATCH] tty: n_gsm: fix decoupled mux resource
The active mux instances are managed in the gsm_mux array and via mux_get()
and mux_put() functions separately. This gives a very loose coupling
between the actual instance and the gsm_mux array which manages it. It also
results in unnecessary lockings which makes it prone to failures. And it
creates a race condition if more than the maximum number of mux instances
are requested while the user changes the parameters of an active instance.
The user may loose ownership of the current mux instance in this case.
Fix this by moving the gsm_mux array handling to the mux allocation and
deallocation functions.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
Cc: stable(a)vger.kernel.org
Signed-off-by: Daniel Starke <daniel.starke(a)siemens.com>
Link: https://lore.kernel.org/r/20220414094225.4527-3-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index daaffcfadaae..f546dfe03d29 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2136,18 +2136,6 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc)
/* Finish outstanding timers, making sure they are done */
del_timer_sync(&gsm->t2_timer);
- spin_lock(&gsm_mux_lock);
- for (i = 0; i < MAX_MUX; i++) {
- if (gsm_mux[i] == gsm) {
- gsm_mux[i] = NULL;
- break;
- }
- }
- spin_unlock(&gsm_mux_lock);
- /* open failed before registering => nothing to do */
- if (i == MAX_MUX)
- return;
-
/* Free up any link layer users */
for (i = 0; i < NUM_DLCI; i++)
if (gsm->dlci[i])
@@ -2171,7 +2159,6 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc)
static int gsm_activate_mux(struct gsm_mux *gsm)
{
struct gsm_dlci *dlci;
- int i = 0;
timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
init_waitqueue_head(&gsm->event);
@@ -2183,18 +2170,6 @@ static int gsm_activate_mux(struct gsm_mux *gsm)
else
gsm->receive = gsm1_receive;
- spin_lock(&gsm_mux_lock);
- for (i = 0; i < MAX_MUX; i++) {
- if (gsm_mux[i] == NULL) {
- gsm->num = i;
- gsm_mux[i] = gsm;
- break;
- }
- }
- spin_unlock(&gsm_mux_lock);
- if (i == MAX_MUX)
- return -EBUSY;
-
dlci = gsm_dlci_alloc(gsm, 0);
if (dlci == NULL)
return -ENOMEM;
@@ -2210,6 +2185,15 @@ static int gsm_activate_mux(struct gsm_mux *gsm)
*/
static void gsm_free_mux(struct gsm_mux *gsm)
{
+ int i;
+
+ for (i = 0; i < MAX_MUX; i++) {
+ if (gsm == gsm_mux[i]) {
+ gsm_mux[i] = NULL;
+ break;
+ }
+ }
+ mutex_destroy(&gsm->mutex);
kfree(gsm->txframe);
kfree(gsm->buf);
kfree(gsm);
@@ -2229,12 +2213,20 @@ static void gsm_free_muxr(struct kref *ref)
static inline void mux_get(struct gsm_mux *gsm)
{
+ unsigned long flags;
+
+ spin_lock_irqsave(&gsm_mux_lock, flags);
kref_get(&gsm->ref);
+ spin_unlock_irqrestore(&gsm_mux_lock, flags);
}
static inline void mux_put(struct gsm_mux *gsm)
{
+ unsigned long flags;
+
+ spin_lock_irqsave(&gsm_mux_lock, flags);
kref_put(&gsm->ref, gsm_free_muxr);
+ spin_unlock_irqrestore(&gsm_mux_lock, flags);
}
static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
@@ -2255,6 +2247,7 @@ static inline unsigned int mux_line_to_num(unsigned int line)
static struct gsm_mux *gsm_alloc_mux(void)
{
+ int i;
struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
if (gsm == NULL)
return NULL;
@@ -2284,6 +2277,26 @@ static struct gsm_mux *gsm_alloc_mux(void)
gsm->mtu = 64;
gsm->dead = true; /* Avoid early tty opens */
+ /* Store the instance to the mux array or abort if no space is
+ * available.
+ */
+ spin_lock(&gsm_mux_lock);
+ for (i = 0; i < MAX_MUX; i++) {
+ if (!gsm_mux[i]) {
+ gsm_mux[i] = gsm;
+ gsm->num = i;
+ break;
+ }
+ }
+ spin_unlock(&gsm_mux_lock);
+ if (i == MAX_MUX) {
+ mutex_destroy(&gsm->mutex);
+ kfree(gsm->txframe);
+ kfree(gsm->buf);
+ kfree(gsm);
+ return NULL;
+ }
+
return gsm;
}