May 2022 - Linux-stable-mirror

FAILED: patch "[PATCH] tty: n_gsm: fix software flow control handling" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

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 f4f7d63287217ba25e5c80f5faae5e4f7118790e Mon Sep 17 00:00:00 2001 From: Daniel Starke <daniel.starke(a)siemens.com> Date: Fri, 22 Apr 2022 00:10:25 -0700 Subject: [PATCH] tty: n_gsm: fix software flow control handling 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.… The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to the newer 27.010 here. Chapter 5.4.8.1 states that XON/XOFF characters shall be used instead of Fcon/Fcoff command in advanced option mode to handle flow control. Chapter 5.4.8.2 describes how XON/XOFF characters shall be handled. Basic option mode only used Fcon/Fcoff commands and no XON/XOFF characters. These are treated as data bytes here. The current implementation uses the gsm_mux field 'constipated' to handle flow control from the remote peer and the gsm_dlci field 'constipated' to handle flow control from each DLCI. The later is unrelated to this patch. The gsm_mux field is correctly set for Fcon/Fcoff commands in gsm_control_message(). However, the same is not true for XON/XOFF characters in gsm1_receive(). Disable software flow control handling in the tty to allow explicit handling by n_gsm. Add the missing handling in advanced option mode for gsm_mux in gsm1_receive() to comply with the standard. This patch depends on the following commit: Commit 8838b2af23ca ("tty: n_gsm: fix SW flow control encoding/handling") 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/20220422071025.5490-3-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 570f0b8b7576..8652308c187f 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -232,6 +232,7 @@ struct gsm_mux { int initiator; /* Did we initiate connection */ bool dead; /* Has the mux been shut down */ struct gsm_dlci *dlci[NUM_DLCI]; + int old_c_iflag; /* termios c_iflag value before attach */ bool constipated; /* Asked by remote to shut up */ spinlock_t tx_lock; @@ -2022,6 +2023,16 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) static void gsm1_receive(struct gsm_mux *gsm, unsigned char c) { + /* handle XON/XOFF */ + if ((c & ISO_IEC_646_MASK) == XON) { + gsm->constipated = true; + return; + } else if ((c & ISO_IEC_646_MASK) == XOFF) { + gsm->constipated = false; + /* Kick the link in case it is idling */ + gsm_data_kick(gsm, NULL); + return; + } if (c == GSM1_SOF) { /* EOF is only valid in frame if we have got to the data state */ if (gsm->state == GSM_DATA) { @@ -2449,6 +2460,9 @@ static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) int ret, i; gsm->tty = tty_kref_get(tty); + /* Turn off tty XON/XOFF handling to handle it explicitly. */ + gsm->old_c_iflag = tty->termios.c_iflag; + tty->termios.c_iflag &= (IXON | IXOFF); ret = gsm_activate_mux(gsm); if (ret != 0) tty_kref_put(gsm->tty); @@ -2489,6 +2503,8 @@ static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) WARN_ON(tty != gsm->tty); for (i = 1; i < NUM_DLCI; i++) tty_unregister_device(gsm_tty_driver, base + i); + /* Restore tty XON/XOFF handling. */ + gsm->tty->termios.c_iflag = gsm->old_c_iflag; tty_kref_put(gsm->tty); gsm->tty = NULL; }

3 years, 7 months

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FAILED: patch "[PATCH] tty: n_gsm: fix invalid use of MSC in advanced option" failed to apply to 4.9-stable tree

by gregkh＠linuxfoundation.org

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 c19ffe00fed6bb423d81406d2a7e5793074c7d83 Mon Sep 17 00:00:00 2001 From: Daniel Starke <daniel.starke(a)siemens.com> Date: Fri, 22 Apr 2022 00:10:24 -0700 Subject: [PATCH] tty: n_gsm: fix invalid use of MSC in advanced option 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.… The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to the newer 27.010 here. Chapter 5.4.6.3.7 states that the Modem Status Command (MSC) shall only be used if the basic option was chosen. The current implementation uses MSC frames even if advanced option was chosen to inform the peer about modem line state updates. A standard conform peer may choose to discard these frames in advanced option mode. Furthermore, gsmtty_modem_update() is not part of the 'tty_operations' functions despite its name. Rename gsmtty_modem_update() to gsm_modem_update() to clarify this. Split its function into gsm_modem_upd_via_data() and gsm_modem_upd_via_msc() depending on the encoding and adaption. Introduce gsm_dlci_modem_output() as adaption of gsm_dlci_data_output() to encode and queue empty frames in advanced option mode. Use it in gsm_modem_upd_via_data(). gsm_modem_upd_via_msc() is based on the initial gsmtty_modem_update() function which used only MSC frames to update modem states. 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/20220422071025.5490-2-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 99fe54247a87..570f0b8b7576 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -366,7 +366,7 @@ static const u8 gsm_fcs8[256] = { #define GOOD_FCS 0xCF static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len); -static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk); +static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk); /** * gsm_fcs_add - update FCS @@ -914,6 +914,63 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, return size; } +/** + * gsm_dlci_modem_output - try and push modem status out of a DLCI + * @gsm: mux + * @dlci: the DLCI to pull modem status from + * @brk: break signal + * + * Push an empty frame in to the transmit queue to update the modem status + * bits and to transmit an optional break. + * + * Caller must hold the tx_lock of the mux. + */ + +static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci, + u8 brk) +{ + u8 *dp = NULL; + struct gsm_msg *msg; + int size; + + /* for modem bits without break data */ + if (dlci->adaption == 1) { + size = 0; + } else if (dlci->adaption == 2) { + size = 1; + if (brk > 0) + size++; + } else { + pr_err("%s: unsupported adaption %d\n", __func__, + dlci->adaption); + } + + msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); + if (!msg) { + pr_err("%s: gsm_data_alloc error", __func__); + return -ENOMEM; + } + dp = msg->data; + switch (dlci->adaption) { + case 1: /* Unstructured */ + break; + case 2: /* Unstructured with modem bits. */ + if (brk == 0) { + *dp++ = (gsm_encode_modem(dlci) << 1) | EA; + } else { + *dp++ = gsm_encode_modem(dlci) << 1; + *dp++ = (brk << 4) | 2 | EA; /* Length, Break, EA */ + } + break; + default: + /* Handled above */ + break; + } + + __gsm_data_queue(dlci, msg); + return size; +} + /** * gsm_dlci_data_sweep - look for data to send * @gsm: the GSM mux @@ -1464,7 +1521,7 @@ static void gsm_dlci_open(struct gsm_dlci *dlci) pr_debug("DLCI %d goes open.\n", dlci->addr); /* Send current modem state */ if (dlci->addr) - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); wake_up(&dlci->gsm->event); } @@ -2897,12 +2954,43 @@ static struct tty_ldisc_ops tty_ldisc_packet = { #define TX_SIZE 512 -static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) +/** + * gsm_modem_upd_via_data - send modem bits via convergence layer + * @dlci: channel + * @brk: break signal + * + * Send an empty frame to signal mobile state changes and to transmit the + * break signal for adaption 2. + */ + +static void gsm_modem_upd_via_data(struct gsm_dlci *dlci, u8 brk) +{ + struct gsm_mux *gsm = dlci->gsm; + unsigned long flags; + + if (dlci->state != DLCI_OPEN || dlci->adaption != 2) + return; + + spin_lock_irqsave(&gsm->tx_lock, flags); + gsm_dlci_modem_output(gsm, dlci, brk); + spin_unlock_irqrestore(&gsm->tx_lock, flags); +} + +/** + * gsm_modem_upd_via_msc - send modem bits via control frame + * @dlci: channel + * @brk: break signal + */ + +static int gsm_modem_upd_via_msc(struct gsm_dlci *dlci, u8 brk) { u8 modembits[3]; struct gsm_control *ctrl; int len = 2; + if (dlci->gsm->encoding != 0) + return 0; + modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */ if (!brk) { modembits[1] = (gsm_encode_modem(dlci) << 1) | EA; @@ -2917,6 +3005,27 @@ static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) return gsm_control_wait(dlci->gsm, ctrl); } +/** + * gsm_modem_update - send modem status line state + * @dlci: channel + * @brk: break signal + */ + +static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk) +{ + if (dlci->adaption == 2) { + /* Send convergence layer type 2 empty data frame. */ + gsm_modem_upd_via_data(dlci, brk); + return 0; + } else if (dlci->gsm->encoding == 0) { + /* Send as MSC control message. */ + return gsm_modem_upd_via_msc(dlci, brk); + } + + /* Modem status lines are not supported. */ + return -EPROTONOSUPPORT; +} + static int gsm_carrier_raised(struct tty_port *port) { struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); @@ -2949,7 +3058,7 @@ static void gsm_dtr_rts(struct tty_port *port, int onoff) modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); if (modem_tx != dlci->modem_tx) { dlci->modem_tx = modem_tx; - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } } @@ -3140,7 +3249,7 @@ static int gsmtty_tiocmset(struct tty_struct *tty, if (modem_tx != dlci->modem_tx) { dlci->modem_tx = modem_tx; - return gsmtty_modem_update(dlci, 0); + return gsm_modem_update(dlci, 0); } return 0; } @@ -3201,7 +3310,7 @@ static void gsmtty_throttle(struct tty_struct *tty) dlci->modem_tx &= ~TIOCM_RTS; dlci->throttled = true; /* Send an MSC with RTS cleared */ - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } static void gsmtty_unthrottle(struct tty_struct *tty) @@ -3213,7 +3322,7 @@ static void gsmtty_unthrottle(struct tty_struct *tty) dlci->modem_tx |= TIOCM_RTS; dlci->throttled = false; /* Send an MSC with RTS set */ - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } static int gsmtty_break_ctl(struct tty_struct *tty, int state) @@ -3231,7 +3340,7 @@ static int gsmtty_break_ctl(struct tty_struct *tty, int state) if (encode > 0x0F) encode = 0x0F; /* Best effort */ } - return gsmtty_modem_update(dlci, encode); + return gsm_modem_update(dlci, encode); } static void gsmtty_cleanup(struct tty_struct *tty)

3 years, 7 months

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FAILED: patch "[PATCH] tty: n_gsm: fix invalid use of MSC in advanced option" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

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 c19ffe00fed6bb423d81406d2a7e5793074c7d83 Mon Sep 17 00:00:00 2001 From: Daniel Starke <daniel.starke(a)siemens.com> Date: Fri, 22 Apr 2022 00:10:24 -0700 Subject: [PATCH] tty: n_gsm: fix invalid use of MSC in advanced option 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.… The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to the newer 27.010 here. Chapter 5.4.6.3.7 states that the Modem Status Command (MSC) shall only be used if the basic option was chosen. The current implementation uses MSC frames even if advanced option was chosen to inform the peer about modem line state updates. A standard conform peer may choose to discard these frames in advanced option mode. Furthermore, gsmtty_modem_update() is not part of the 'tty_operations' functions despite its name. Rename gsmtty_modem_update() to gsm_modem_update() to clarify this. Split its function into gsm_modem_upd_via_data() and gsm_modem_upd_via_msc() depending on the encoding and adaption. Introduce gsm_dlci_modem_output() as adaption of gsm_dlci_data_output() to encode and queue empty frames in advanced option mode. Use it in gsm_modem_upd_via_data(). gsm_modem_upd_via_msc() is based on the initial gsmtty_modem_update() function which used only MSC frames to update modem states. 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/20220422071025.5490-2-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 99fe54247a87..570f0b8b7576 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -366,7 +366,7 @@ static const u8 gsm_fcs8[256] = { #define GOOD_FCS 0xCF static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len); -static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk); +static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk); /** * gsm_fcs_add - update FCS @@ -914,6 +914,63 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, return size; } +/** + * gsm_dlci_modem_output - try and push modem status out of a DLCI + * @gsm: mux + * @dlci: the DLCI to pull modem status from + * @brk: break signal + * + * Push an empty frame in to the transmit queue to update the modem status + * bits and to transmit an optional break. + * + * Caller must hold the tx_lock of the mux. + */ + +static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci, + u8 brk) +{ + u8 *dp = NULL; + struct gsm_msg *msg; + int size; + + /* for modem bits without break data */ + if (dlci->adaption == 1) { + size = 0; + } else if (dlci->adaption == 2) { + size = 1; + if (brk > 0) + size++; + } else { + pr_err("%s: unsupported adaption %d\n", __func__, + dlci->adaption); + } + + msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); + if (!msg) { + pr_err("%s: gsm_data_alloc error", __func__); + return -ENOMEM; + } + dp = msg->data; + switch (dlci->adaption) { + case 1: /* Unstructured */ + break; + case 2: /* Unstructured with modem bits. */ + if (brk == 0) { + *dp++ = (gsm_encode_modem(dlci) << 1) | EA; + } else { + *dp++ = gsm_encode_modem(dlci) << 1; + *dp++ = (brk << 4) | 2 | EA; /* Length, Break, EA */ + } + break; + default: + /* Handled above */ + break; + } + + __gsm_data_queue(dlci, msg); + return size; +} + /** * gsm_dlci_data_sweep - look for data to send * @gsm: the GSM mux @@ -1464,7 +1521,7 @@ static void gsm_dlci_open(struct gsm_dlci *dlci) pr_debug("DLCI %d goes open.\n", dlci->addr); /* Send current modem state */ if (dlci->addr) - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); wake_up(&dlci->gsm->event); } @@ -2897,12 +2954,43 @@ static struct tty_ldisc_ops tty_ldisc_packet = { #define TX_SIZE 512 -static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) +/** + * gsm_modem_upd_via_data - send modem bits via convergence layer + * @dlci: channel + * @brk: break signal + * + * Send an empty frame to signal mobile state changes and to transmit the + * break signal for adaption 2. + */ + +static void gsm_modem_upd_via_data(struct gsm_dlci *dlci, u8 brk) +{ + struct gsm_mux *gsm = dlci->gsm; + unsigned long flags; + + if (dlci->state != DLCI_OPEN || dlci->adaption != 2) + return; + + spin_lock_irqsave(&gsm->tx_lock, flags); + gsm_dlci_modem_output(gsm, dlci, brk); + spin_unlock_irqrestore(&gsm->tx_lock, flags); +} + +/** + * gsm_modem_upd_via_msc - send modem bits via control frame + * @dlci: channel + * @brk: break signal + */ + +static int gsm_modem_upd_via_msc(struct gsm_dlci *dlci, u8 brk) { u8 modembits[3]; struct gsm_control *ctrl; int len = 2; + if (dlci->gsm->encoding != 0) + return 0; + modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */ if (!brk) { modembits[1] = (gsm_encode_modem(dlci) << 1) | EA; @@ -2917,6 +3005,27 @@ static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) return gsm_control_wait(dlci->gsm, ctrl); } +/** + * gsm_modem_update - send modem status line state + * @dlci: channel + * @brk: break signal + */ + +static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk) +{ + if (dlci->adaption == 2) { + /* Send convergence layer type 2 empty data frame. */ + gsm_modem_upd_via_data(dlci, brk); + return 0; + } else if (dlci->gsm->encoding == 0) { + /* Send as MSC control message. */ + return gsm_modem_upd_via_msc(dlci, brk); + } + + /* Modem status lines are not supported. */ + return -EPROTONOSUPPORT; +} + static int gsm_carrier_raised(struct tty_port *port) { struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); @@ -2949,7 +3058,7 @@ static void gsm_dtr_rts(struct tty_port *port, int onoff) modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); if (modem_tx != dlci->modem_tx) { dlci->modem_tx = modem_tx; - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } } @@ -3140,7 +3249,7 @@ static int gsmtty_tiocmset(struct tty_struct *tty, if (modem_tx != dlci->modem_tx) { dlci->modem_tx = modem_tx; - return gsmtty_modem_update(dlci, 0); + return gsm_modem_update(dlci, 0); } return 0; } @@ -3201,7 +3310,7 @@ static void gsmtty_throttle(struct tty_struct *tty) dlci->modem_tx &= ~TIOCM_RTS; dlci->throttled = true; /* Send an MSC with RTS cleared */ - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } static void gsmtty_unthrottle(struct tty_struct *tty) @@ -3213,7 +3322,7 @@ static void gsmtty_unthrottle(struct tty_struct *tty) dlci->modem_tx |= TIOCM_RTS; dlci->throttled = false; /* Send an MSC with RTS set */ - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } static int gsmtty_break_ctl(struct tty_struct *tty, int state) @@ -3231,7 +3340,7 @@ static int gsmtty_break_ctl(struct tty_struct *tty, int state) if (encode > 0x0F) encode = 0x0F; /* Best effort */ } - return gsmtty_modem_update(dlci, encode); + return gsm_modem_update(dlci, encode); } static void gsmtty_cleanup(struct tty_struct *tty)

3 years, 7 months

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FAILED: patch "[PATCH] tty: n_gsm: fix invalid use of MSC in advanced option" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

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 c19ffe00fed6bb423d81406d2a7e5793074c7d83 Mon Sep 17 00:00:00 2001 From: Daniel Starke <daniel.starke(a)siemens.com> Date: Fri, 22 Apr 2022 00:10:24 -0700 Subject: [PATCH] tty: n_gsm: fix invalid use of MSC in advanced option 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.… The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to the newer 27.010 here. Chapter 5.4.6.3.7 states that the Modem Status Command (MSC) shall only be used if the basic option was chosen. The current implementation uses MSC frames even if advanced option was chosen to inform the peer about modem line state updates. A standard conform peer may choose to discard these frames in advanced option mode. Furthermore, gsmtty_modem_update() is not part of the 'tty_operations' functions despite its name. Rename gsmtty_modem_update() to gsm_modem_update() to clarify this. Split its function into gsm_modem_upd_via_data() and gsm_modem_upd_via_msc() depending on the encoding and adaption. Introduce gsm_dlci_modem_output() as adaption of gsm_dlci_data_output() to encode and queue empty frames in advanced option mode. Use it in gsm_modem_upd_via_data(). gsm_modem_upd_via_msc() is based on the initial gsmtty_modem_update() function which used only MSC frames to update modem states. 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/20220422071025.5490-2-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 99fe54247a87..570f0b8b7576 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -366,7 +366,7 @@ static const u8 gsm_fcs8[256] = { #define GOOD_FCS 0xCF static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len); -static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk); +static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk); /** * gsm_fcs_add - update FCS @@ -914,6 +914,63 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, return size; } +/** + * gsm_dlci_modem_output - try and push modem status out of a DLCI + * @gsm: mux + * @dlci: the DLCI to pull modem status from + * @brk: break signal + * + * Push an empty frame in to the transmit queue to update the modem status + * bits and to transmit an optional break. + * + * Caller must hold the tx_lock of the mux. + */ + +static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci, + u8 brk) +{ + u8 *dp = NULL; + struct gsm_msg *msg; + int size; + + /* for modem bits without break data */ + if (dlci->adaption == 1) { + size = 0; + } else if (dlci->adaption == 2) { + size = 1; + if (brk > 0) + size++; + } else { + pr_err("%s: unsupported adaption %d\n", __func__, + dlci->adaption); + } + + msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); + if (!msg) { + pr_err("%s: gsm_data_alloc error", __func__); + return -ENOMEM; + } + dp = msg->data; + switch (dlci->adaption) { + case 1: /* Unstructured */ + break; + case 2: /* Unstructured with modem bits. */ + if (brk == 0) { + *dp++ = (gsm_encode_modem(dlci) << 1) | EA; + } else { + *dp++ = gsm_encode_modem(dlci) << 1; + *dp++ = (brk << 4) | 2 | EA; /* Length, Break, EA */ + } + break; + default: + /* Handled above */ + break; + } + + __gsm_data_queue(dlci, msg); + return size; +} + /** * gsm_dlci_data_sweep - look for data to send * @gsm: the GSM mux @@ -1464,7 +1521,7 @@ static void gsm_dlci_open(struct gsm_dlci *dlci) pr_debug("DLCI %d goes open.\n", dlci->addr); /* Send current modem state */ if (dlci->addr) - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); wake_up(&dlci->gsm->event); } @@ -2897,12 +2954,43 @@ static struct tty_ldisc_ops tty_ldisc_packet = { #define TX_SIZE 512 -static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) +/** + * gsm_modem_upd_via_data - send modem bits via convergence layer + * @dlci: channel + * @brk: break signal + * + * Send an empty frame to signal mobile state changes and to transmit the + * break signal for adaption 2. + */ + +static void gsm_modem_upd_via_data(struct gsm_dlci *dlci, u8 brk) +{ + struct gsm_mux *gsm = dlci->gsm; + unsigned long flags; + + if (dlci->state != DLCI_OPEN || dlci->adaption != 2) + return; + + spin_lock_irqsave(&gsm->tx_lock, flags); + gsm_dlci_modem_output(gsm, dlci, brk); + spin_unlock_irqrestore(&gsm->tx_lock, flags); +} + +/** + * gsm_modem_upd_via_msc - send modem bits via control frame + * @dlci: channel + * @brk: break signal + */ + +static int gsm_modem_upd_via_msc(struct gsm_dlci *dlci, u8 brk) { u8 modembits[3]; struct gsm_control *ctrl; int len = 2; + if (dlci->gsm->encoding != 0) + return 0; + modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */ if (!brk) { modembits[1] = (gsm_encode_modem(dlci) << 1) | EA; @@ -2917,6 +3005,27 @@ static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) return gsm_control_wait(dlci->gsm, ctrl); } +/** + * gsm_modem_update - send modem status line state + * @dlci: channel + * @brk: break signal + */ + +static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk) +{ + if (dlci->adaption == 2) { + /* Send convergence layer type 2 empty data frame. */ + gsm_modem_upd_via_data(dlci, brk); + return 0; + } else if (dlci->gsm->encoding == 0) { + /* Send as MSC control message. */ + return gsm_modem_upd_via_msc(dlci, brk); + } + + /* Modem status lines are not supported. */ + return -EPROTONOSUPPORT; +} + static int gsm_carrier_raised(struct tty_port *port) { struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); @@ -2949,7 +3058,7 @@ static void gsm_dtr_rts(struct tty_port *port, int onoff) modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); if (modem_tx != dlci->modem_tx) { dlci->modem_tx = modem_tx; - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } } @@ -3140,7 +3249,7 @@ static int gsmtty_tiocmset(struct tty_struct *tty, if (modem_tx != dlci->modem_tx) { dlci->modem_tx = modem_tx; - return gsmtty_modem_update(dlci, 0); + return gsm_modem_update(dlci, 0); } return 0; } @@ -3201,7 +3310,7 @@ static void gsmtty_throttle(struct tty_struct *tty) dlci->modem_tx &= ~TIOCM_RTS; dlci->throttled = true; /* Send an MSC with RTS cleared */ - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } static void gsmtty_unthrottle(struct tty_struct *tty) @@ -3213,7 +3322,7 @@ static void gsmtty_unthrottle(struct tty_struct *tty) dlci->modem_tx |= TIOCM_RTS; dlci->throttled = false; /* Send an MSC with RTS set */ - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } static int gsmtty_break_ctl(struct tty_struct *tty, int state) @@ -3231,7 +3340,7 @@ static int gsmtty_break_ctl(struct tty_struct *tty, int state) if (encode > 0x0F) encode = 0x0F; /* Best effort */ } - return gsmtty_modem_update(dlci, encode); + return gsm_modem_update(dlci, encode); } static void gsmtty_cleanup(struct tty_struct *tty)

3 years, 7 months

1
0
0 0

FAILED: patch "[PATCH] tty: n_gsm: fix invalid use of MSC in advanced option" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

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 c19ffe00fed6bb423d81406d2a7e5793074c7d83 Mon Sep 17 00:00:00 2001 From: Daniel Starke <daniel.starke(a)siemens.com> Date: Fri, 22 Apr 2022 00:10:24 -0700 Subject: [PATCH] tty: n_gsm: fix invalid use of MSC in advanced option 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.… The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to the newer 27.010 here. Chapter 5.4.6.3.7 states that the Modem Status Command (MSC) shall only be used if the basic option was chosen. The current implementation uses MSC frames even if advanced option was chosen to inform the peer about modem line state updates. A standard conform peer may choose to discard these frames in advanced option mode. Furthermore, gsmtty_modem_update() is not part of the 'tty_operations' functions despite its name. Rename gsmtty_modem_update() to gsm_modem_update() to clarify this. Split its function into gsm_modem_upd_via_data() and gsm_modem_upd_via_msc() depending on the encoding and adaption. Introduce gsm_dlci_modem_output() as adaption of gsm_dlci_data_output() to encode and queue empty frames in advanced option mode. Use it in gsm_modem_upd_via_data(). gsm_modem_upd_via_msc() is based on the initial gsmtty_modem_update() function which used only MSC frames to update modem states. 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/20220422071025.5490-2-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 99fe54247a87..570f0b8b7576 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -366,7 +366,7 @@ static const u8 gsm_fcs8[256] = { #define GOOD_FCS 0xCF static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len); -static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk); +static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk); /** * gsm_fcs_add - update FCS @@ -914,6 +914,63 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, return size; } +/** + * gsm_dlci_modem_output - try and push modem status out of a DLCI + * @gsm: mux + * @dlci: the DLCI to pull modem status from + * @brk: break signal + * + * Push an empty frame in to the transmit queue to update the modem status + * bits and to transmit an optional break. + * + * Caller must hold the tx_lock of the mux. + */ + +static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci, + u8 brk) +{ + u8 *dp = NULL; + struct gsm_msg *msg; + int size; + + /* for modem bits without break data */ + if (dlci->adaption == 1) { + size = 0; + } else if (dlci->adaption == 2) { + size = 1; + if (brk > 0) + size++; + } else { + pr_err("%s: unsupported adaption %d\n", __func__, + dlci->adaption); + } + + msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); + if (!msg) { + pr_err("%s: gsm_data_alloc error", __func__); + return -ENOMEM; + } + dp = msg->data; + switch (dlci->adaption) { + case 1: /* Unstructured */ + break; + case 2: /* Unstructured with modem bits. */ + if (brk == 0) { + *dp++ = (gsm_encode_modem(dlci) << 1) | EA; + } else { + *dp++ = gsm_encode_modem(dlci) << 1; + *dp++ = (brk << 4) | 2 | EA; /* Length, Break, EA */ + } + break; + default: + /* Handled above */ + break; + } + + __gsm_data_queue(dlci, msg); + return size; +} + /** * gsm_dlci_data_sweep - look for data to send * @gsm: the GSM mux @@ -1464,7 +1521,7 @@ static void gsm_dlci_open(struct gsm_dlci *dlci) pr_debug("DLCI %d goes open.\n", dlci->addr); /* Send current modem state */ if (dlci->addr) - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); wake_up(&dlci->gsm->event); } @@ -2897,12 +2954,43 @@ static struct tty_ldisc_ops tty_ldisc_packet = { #define TX_SIZE 512 -static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) +/** + * gsm_modem_upd_via_data - send modem bits via convergence layer + * @dlci: channel + * @brk: break signal + * + * Send an empty frame to signal mobile state changes and to transmit the + * break signal for adaption 2. + */ + +static void gsm_modem_upd_via_data(struct gsm_dlci *dlci, u8 brk) +{ + struct gsm_mux *gsm = dlci->gsm; + unsigned long flags; + + if (dlci->state != DLCI_OPEN || dlci->adaption != 2) + return; + + spin_lock_irqsave(&gsm->tx_lock, flags); + gsm_dlci_modem_output(gsm, dlci, brk); + spin_unlock_irqrestore(&gsm->tx_lock, flags); +} + +/** + * gsm_modem_upd_via_msc - send modem bits via control frame + * @dlci: channel + * @brk: break signal + */ + +static int gsm_modem_upd_via_msc(struct gsm_dlci *dlci, u8 brk) { u8 modembits[3]; struct gsm_control *ctrl; int len = 2; + if (dlci->gsm->encoding != 0) + return 0; + modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */ if (!brk) { modembits[1] = (gsm_encode_modem(dlci) << 1) | EA; @@ -2917,6 +3005,27 @@ static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) return gsm_control_wait(dlci->gsm, ctrl); } +/** + * gsm_modem_update - send modem status line state + * @dlci: channel + * @brk: break signal + */ + +static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk) +{ + if (dlci->adaption == 2) { + /* Send convergence layer type 2 empty data frame. */ + gsm_modem_upd_via_data(dlci, brk); + return 0; + } else if (dlci->gsm->encoding == 0) { + /* Send as MSC control message. */ + return gsm_modem_upd_via_msc(dlci, brk); + } + + /* Modem status lines are not supported. */ + return -EPROTONOSUPPORT; +} + static int gsm_carrier_raised(struct tty_port *port) { struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); @@ -2949,7 +3058,7 @@ static void gsm_dtr_rts(struct tty_port *port, int onoff) modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); if (modem_tx != dlci->modem_tx) { dlci->modem_tx = modem_tx; - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } } @@ -3140,7 +3249,7 @@ static int gsmtty_tiocmset(struct tty_struct *tty, if (modem_tx != dlci->modem_tx) { dlci->modem_tx = modem_tx; - return gsmtty_modem_update(dlci, 0); + return gsm_modem_update(dlci, 0); } return 0; } @@ -3201,7 +3310,7 @@ static void gsmtty_throttle(struct tty_struct *tty) dlci->modem_tx &= ~TIOCM_RTS; dlci->throttled = true; /* Send an MSC with RTS cleared */ - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } static void gsmtty_unthrottle(struct tty_struct *tty) @@ -3213,7 +3322,7 @@ static void gsmtty_unthrottle(struct tty_struct *tty) dlci->modem_tx |= TIOCM_RTS; dlci->throttled = false; /* Send an MSC with RTS set */ - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } static int gsmtty_break_ctl(struct tty_struct *tty, int state) @@ -3231,7 +3340,7 @@ static int gsmtty_break_ctl(struct tty_struct *tty, int state) if (encode > 0x0F) encode = 0x0F; /* Best effort */ } - return gsmtty_modem_update(dlci, encode); + return gsm_modem_update(dlci, encode); } static void gsmtty_cleanup(struct tty_struct *tty)

3 years, 7 months

1
0
0 0

FAILED: patch "[PATCH] tty: n_gsm: fix invalid use of MSC in advanced option" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

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 c19ffe00fed6bb423d81406d2a7e5793074c7d83 Mon Sep 17 00:00:00 2001 From: Daniel Starke <daniel.starke(a)siemens.com> Date: Fri, 22 Apr 2022 00:10:24 -0700 Subject: [PATCH] tty: n_gsm: fix invalid use of MSC in advanced option 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.… The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to the newer 27.010 here. Chapter 5.4.6.3.7 states that the Modem Status Command (MSC) shall only be used if the basic option was chosen. The current implementation uses MSC frames even if advanced option was chosen to inform the peer about modem line state updates. A standard conform peer may choose to discard these frames in advanced option mode. Furthermore, gsmtty_modem_update() is not part of the 'tty_operations' functions despite its name. Rename gsmtty_modem_update() to gsm_modem_update() to clarify this. Split its function into gsm_modem_upd_via_data() and gsm_modem_upd_via_msc() depending on the encoding and adaption. Introduce gsm_dlci_modem_output() as adaption of gsm_dlci_data_output() to encode and queue empty frames in advanced option mode. Use it in gsm_modem_upd_via_data(). gsm_modem_upd_via_msc() is based on the initial gsmtty_modem_update() function which used only MSC frames to update modem states. 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/20220422071025.5490-2-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 99fe54247a87..570f0b8b7576 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -366,7 +366,7 @@ static const u8 gsm_fcs8[256] = { #define GOOD_FCS 0xCF static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len); -static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk); +static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk); /** * gsm_fcs_add - update FCS @@ -914,6 +914,63 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, return size; } +/** + * gsm_dlci_modem_output - try and push modem status out of a DLCI + * @gsm: mux + * @dlci: the DLCI to pull modem status from + * @brk: break signal + * + * Push an empty frame in to the transmit queue to update the modem status + * bits and to transmit an optional break. + * + * Caller must hold the tx_lock of the mux. + */ + +static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci, + u8 brk) +{ + u8 *dp = NULL; + struct gsm_msg *msg; + int size; + + /* for modem bits without break data */ + if (dlci->adaption == 1) { + size = 0; + } else if (dlci->adaption == 2) { + size = 1; + if (brk > 0) + size++; + } else { + pr_err("%s: unsupported adaption %d\n", __func__, + dlci->adaption); + } + + msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); + if (!msg) { + pr_err("%s: gsm_data_alloc error", __func__); + return -ENOMEM; + } + dp = msg->data; + switch (dlci->adaption) { + case 1: /* Unstructured */ + break; + case 2: /* Unstructured with modem bits. */ + if (brk == 0) { + *dp++ = (gsm_encode_modem(dlci) << 1) | EA; + } else { + *dp++ = gsm_encode_modem(dlci) << 1; + *dp++ = (brk << 4) | 2 | EA; /* Length, Break, EA */ + } + break; + default: + /* Handled above */ + break; + } + + __gsm_data_queue(dlci, msg); + return size; +} + /** * gsm_dlci_data_sweep - look for data to send * @gsm: the GSM mux @@ -1464,7 +1521,7 @@ static void gsm_dlci_open(struct gsm_dlci *dlci) pr_debug("DLCI %d goes open.\n", dlci->addr); /* Send current modem state */ if (dlci->addr) - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); wake_up(&dlci->gsm->event); } @@ -2897,12 +2954,43 @@ static struct tty_ldisc_ops tty_ldisc_packet = { #define TX_SIZE 512 -static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) +/** + * gsm_modem_upd_via_data - send modem bits via convergence layer + * @dlci: channel + * @brk: break signal + * + * Send an empty frame to signal mobile state changes and to transmit the + * break signal for adaption 2. + */ + +static void gsm_modem_upd_via_data(struct gsm_dlci *dlci, u8 brk) +{ + struct gsm_mux *gsm = dlci->gsm; + unsigned long flags; + + if (dlci->state != DLCI_OPEN || dlci->adaption != 2) + return; + + spin_lock_irqsave(&gsm->tx_lock, flags); + gsm_dlci_modem_output(gsm, dlci, brk); + spin_unlock_irqrestore(&gsm->tx_lock, flags); +} + +/** + * gsm_modem_upd_via_msc - send modem bits via control frame + * @dlci: channel + * @brk: break signal + */ + +static int gsm_modem_upd_via_msc(struct gsm_dlci *dlci, u8 brk) { u8 modembits[3]; struct gsm_control *ctrl; int len = 2; + if (dlci->gsm->encoding != 0) + return 0; + modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */ if (!brk) { modembits[1] = (gsm_encode_modem(dlci) << 1) | EA; @@ -2917,6 +3005,27 @@ static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) return gsm_control_wait(dlci->gsm, ctrl); } +/** + * gsm_modem_update - send modem status line state + * @dlci: channel + * @brk: break signal + */ + +static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk) +{ + if (dlci->adaption == 2) { + /* Send convergence layer type 2 empty data frame. */ + gsm_modem_upd_via_data(dlci, brk); + return 0; + } else if (dlci->gsm->encoding == 0) { + /* Send as MSC control message. */ + return gsm_modem_upd_via_msc(dlci, brk); + } + + /* Modem status lines are not supported. */ + return -EPROTONOSUPPORT; +} + static int gsm_carrier_raised(struct tty_port *port) { struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); @@ -2949,7 +3058,7 @@ static void gsm_dtr_rts(struct tty_port *port, int onoff) modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); if (modem_tx != dlci->modem_tx) { dlci->modem_tx = modem_tx; - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } } @@ -3140,7 +3249,7 @@ static int gsmtty_tiocmset(struct tty_struct *tty, if (modem_tx != dlci->modem_tx) { dlci->modem_tx = modem_tx; - return gsmtty_modem_update(dlci, 0); + return gsm_modem_update(dlci, 0); } return 0; } @@ -3201,7 +3310,7 @@ static void gsmtty_throttle(struct tty_struct *tty) dlci->modem_tx &= ~TIOCM_RTS; dlci->throttled = true; /* Send an MSC with RTS cleared */ - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } static void gsmtty_unthrottle(struct tty_struct *tty) @@ -3213,7 +3322,7 @@ static void gsmtty_unthrottle(struct tty_struct *tty) dlci->modem_tx |= TIOCM_RTS; dlci->throttled = false; /* Send an MSC with RTS set */ - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } static int gsmtty_break_ctl(struct tty_struct *tty, int state) @@ -3231,7 +3340,7 @@ static int gsmtty_break_ctl(struct tty_struct *tty, int state) if (encode > 0x0F) encode = 0x0F; /* Best effort */ } - return gsmtty_modem_update(dlci, encode); + return gsm_modem_update(dlci, encode); } static void gsmtty_cleanup(struct tty_struct *tty)

3 years, 7 months

1
0
0 0

FAILED: patch "[PATCH] tty: n_gsm: fix invalid use of MSC in advanced option" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

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 c19ffe00fed6bb423d81406d2a7e5793074c7d83 Mon Sep 17 00:00:00 2001 From: Daniel Starke <daniel.starke(a)siemens.com> Date: Fri, 22 Apr 2022 00:10:24 -0700 Subject: [PATCH] tty: n_gsm: fix invalid use of MSC in advanced option 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.… The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to the newer 27.010 here. Chapter 5.4.6.3.7 states that the Modem Status Command (MSC) shall only be used if the basic option was chosen. The current implementation uses MSC frames even if advanced option was chosen to inform the peer about modem line state updates. A standard conform peer may choose to discard these frames in advanced option mode. Furthermore, gsmtty_modem_update() is not part of the 'tty_operations' functions despite its name. Rename gsmtty_modem_update() to gsm_modem_update() to clarify this. Split its function into gsm_modem_upd_via_data() and gsm_modem_upd_via_msc() depending on the encoding and adaption. Introduce gsm_dlci_modem_output() as adaption of gsm_dlci_data_output() to encode and queue empty frames in advanced option mode. Use it in gsm_modem_upd_via_data(). gsm_modem_upd_via_msc() is based on the initial gsmtty_modem_update() function which used only MSC frames to update modem states. 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/20220422071025.5490-2-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 99fe54247a87..570f0b8b7576 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -366,7 +366,7 @@ static const u8 gsm_fcs8[256] = { #define GOOD_FCS 0xCF static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len); -static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk); +static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk); /** * gsm_fcs_add - update FCS @@ -914,6 +914,63 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, return size; } +/** + * gsm_dlci_modem_output - try and push modem status out of a DLCI + * @gsm: mux + * @dlci: the DLCI to pull modem status from + * @brk: break signal + * + * Push an empty frame in to the transmit queue to update the modem status + * bits and to transmit an optional break. + * + * Caller must hold the tx_lock of the mux. + */ + +static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci, + u8 brk) +{ + u8 *dp = NULL; + struct gsm_msg *msg; + int size; + + /* for modem bits without break data */ + if (dlci->adaption == 1) { + size = 0; + } else if (dlci->adaption == 2) { + size = 1; + if (brk > 0) + size++; + } else { + pr_err("%s: unsupported adaption %d\n", __func__, + dlci->adaption); + } + + msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); + if (!msg) { + pr_err("%s: gsm_data_alloc error", __func__); + return -ENOMEM; + } + dp = msg->data; + switch (dlci->adaption) { + case 1: /* Unstructured */ + break; + case 2: /* Unstructured with modem bits. */ + if (brk == 0) { + *dp++ = (gsm_encode_modem(dlci) << 1) | EA; + } else { + *dp++ = gsm_encode_modem(dlci) << 1; + *dp++ = (brk << 4) | 2 | EA; /* Length, Break, EA */ + } + break; + default: + /* Handled above */ + break; + } + + __gsm_data_queue(dlci, msg); + return size; +} + /** * gsm_dlci_data_sweep - look for data to send * @gsm: the GSM mux @@ -1464,7 +1521,7 @@ static void gsm_dlci_open(struct gsm_dlci *dlci) pr_debug("DLCI %d goes open.\n", dlci->addr); /* Send current modem state */ if (dlci->addr) - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); wake_up(&dlci->gsm->event); } @@ -2897,12 +2954,43 @@ static struct tty_ldisc_ops tty_ldisc_packet = { #define TX_SIZE 512 -static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) +/** + * gsm_modem_upd_via_data - send modem bits via convergence layer + * @dlci: channel + * @brk: break signal + * + * Send an empty frame to signal mobile state changes and to transmit the + * break signal for adaption 2. + */ + +static void gsm_modem_upd_via_data(struct gsm_dlci *dlci, u8 brk) +{ + struct gsm_mux *gsm = dlci->gsm; + unsigned long flags; + + if (dlci->state != DLCI_OPEN || dlci->adaption != 2) + return; + + spin_lock_irqsave(&gsm->tx_lock, flags); + gsm_dlci_modem_output(gsm, dlci, brk); + spin_unlock_irqrestore(&gsm->tx_lock, flags); +} + +/** + * gsm_modem_upd_via_msc - send modem bits via control frame + * @dlci: channel + * @brk: break signal + */ + +static int gsm_modem_upd_via_msc(struct gsm_dlci *dlci, u8 brk) { u8 modembits[3]; struct gsm_control *ctrl; int len = 2; + if (dlci->gsm->encoding != 0) + return 0; + modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */ if (!brk) { modembits[1] = (gsm_encode_modem(dlci) << 1) | EA; @@ -2917,6 +3005,27 @@ static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) return gsm_control_wait(dlci->gsm, ctrl); } +/** + * gsm_modem_update - send modem status line state + * @dlci: channel + * @brk: break signal + */ + +static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk) +{ + if (dlci->adaption == 2) { + /* Send convergence layer type 2 empty data frame. */ + gsm_modem_upd_via_data(dlci, brk); + return 0; + } else if (dlci->gsm->encoding == 0) { + /* Send as MSC control message. */ + return gsm_modem_upd_via_msc(dlci, brk); + } + + /* Modem status lines are not supported. */ + return -EPROTONOSUPPORT; +} + static int gsm_carrier_raised(struct tty_port *port) { struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); @@ -2949,7 +3058,7 @@ static void gsm_dtr_rts(struct tty_port *port, int onoff) modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); if (modem_tx != dlci->modem_tx) { dlci->modem_tx = modem_tx; - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } } @@ -3140,7 +3249,7 @@ static int gsmtty_tiocmset(struct tty_struct *tty, if (modem_tx != dlci->modem_tx) { dlci->modem_tx = modem_tx; - return gsmtty_modem_update(dlci, 0); + return gsm_modem_update(dlci, 0); } return 0; } @@ -3201,7 +3310,7 @@ static void gsmtty_throttle(struct tty_struct *tty) dlci->modem_tx &= ~TIOCM_RTS; dlci->throttled = true; /* Send an MSC with RTS cleared */ - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } static void gsmtty_unthrottle(struct tty_struct *tty) @@ -3213,7 +3322,7 @@ static void gsmtty_unthrottle(struct tty_struct *tty) dlci->modem_tx |= TIOCM_RTS; dlci->throttled = false; /* Send an MSC with RTS set */ - gsmtty_modem_update(dlci, 0); + gsm_modem_update(dlci, 0); } static int gsmtty_break_ctl(struct tty_struct *tty, int state) @@ -3231,7 +3340,7 @@ static int gsmtty_break_ctl(struct tty_struct *tty, int state) if (encode > 0x0F) encode = 0x0F; /* Best effort */ } - return gsmtty_modem_update(dlci, encode); + return gsm_modem_update(dlci, encode); } static void gsmtty_cleanup(struct tty_struct *tty)

3 years, 7 months

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FAILED: patch "[PATCH] tty: n_gsm: fix broken virtual tty handling" failed to apply to 4.9-stable tree

by gregkh＠linuxfoundation.org

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 a8c5b8255f8a9acd58a4b15ff1c14cd6effd114b Mon Sep 17 00:00:00 2001 From: Daniel Starke <daniel.starke(a)siemens.com> Date: Fri, 22 Apr 2022 00:10:23 -0700 Subject: [PATCH] tty: n_gsm: fix broken virtual tty handling Dynamic virtual tty registration was introduced to allow the user to handle these cases with uevent rules. The following commits relate to this: Commit 5b87686e3203 ("tty: n_gsm: Modify gsmtty driver register method when config requester") Commit 0b91b5332368 ("tty: n_gsm: Save dlci address open status when config requester") Commit 46292622ad73 ("tty: n_gsm: clean up indenting in gsm_queue()") However, the following behavior can be seen with this implementation: - n_gsm ldisc is activated via ioctl - all configuration parameters are set to their default value (initiator=0) - the mux gets activated and attached and gsmtty0 is being registered in in gsm_dlci_open() after DLCI 0 was established (DLCI 0 is the control channel) - the user configures n_gsm via ioctl GSMIOC_SETCONF as initiator - this re-attaches the n_gsm mux - no new gsmtty devices are registered in gsmld_attach_gsm() because the mux is already active - the initiator side registered only the control channel as gsmtty0 (which should never happen) and no user channel tty The commits above make it impossible to operate the initiator side as no user channel tty is or will be available. On the other hand, this behavior will make it also impossible to allow DLCI parameter negotiation on responder side in the future. The responder side first needs to provide a device for the application before the application can set its parameters of the associated DLCI via ioctl. Note that the user application is still able to detect a link establishment without relaying to uevent by waiting for DTR open on responder side. This is the same behavior as on a physical serial interface. And on initiator side a tty hangup can be detected if a link establishment request failed. Revert the commits above completely to always register all user channels and no control channel after mux attachment. No other changes are made. Fixes: 5b87686e3203 ("tty: n_gsm: Modify gsmtty driver register method when config requester") Cc: stable(a)vger.kernel.org Signed-off-by: Daniel Starke <daniel.starke(a)siemens.com> Link: https://lore.kernel.org/r/20220422071025.5490-1-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 979dc9151383..99fe54247a87 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -272,10 +272,6 @@ static DEFINE_SPINLOCK(gsm_mux_lock); static struct tty_driver *gsm_tty_driver; -/* Save dlci open address */ -static int addr_open[256] = { 0 }; -/* Save dlci open count */ -static int addr_cnt; /* * This section of the driver logic implements the GSM encodings * both the basic and the 'advanced'. Reliable transport is not @@ -1185,7 +1181,6 @@ static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen) } static void gsm_dlci_begin_close(struct gsm_dlci *dlci); -static void gsm_dlci_close(struct gsm_dlci *dlci); /** * gsm_control_message - DLCI 0 control processing @@ -1204,28 +1199,15 @@ static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, { u8 buf[1]; unsigned long flags; - struct gsm_dlci *dlci; - int i; - int address; switch (command) { case CMD_CLD: { - if (addr_cnt > 0) { - for (i = 0; i < addr_cnt; i++) { - address = addr_open[i]; - dlci = gsm->dlci[address]; - gsm_dlci_close(dlci); - addr_open[i] = 0; - } - } + struct gsm_dlci *dlci = gsm->dlci[0]; /* Modem wishes to close down */ - dlci = gsm->dlci[0]; if (dlci) { dlci->dead = true; gsm->dead = true; - gsm_dlci_close(dlci); - addr_cnt = 0; - gsm_response(gsm, 0, UA|PF); + gsm_dlci_begin_close(dlci); } } break; @@ -1459,8 +1441,6 @@ static void gsm_dlci_close(struct gsm_dlci *dlci) wake_up_interruptible(&dlci->port.open_wait); } else dlci->gsm->dead = true; - /* Unregister gsmtty driver,report gsmtty dev remove uevent for user */ - tty_unregister_device(gsm_tty_driver, dlci->addr); wake_up(&dlci->gsm->event); /* A DLCI 0 close is a MUX termination so we need to kick that back to userspace somehow */ @@ -1482,8 +1462,6 @@ static void gsm_dlci_open(struct gsm_dlci *dlci) dlci->state = DLCI_OPEN; if (debug & 8) pr_debug("DLCI %d goes open.\n", dlci->addr); - /* Register gsmtty driver,report gsmtty dev add uevent for user */ - tty_register_device(gsm_tty_driver, dlci->addr, NULL); /* Send current modem state */ if (dlci->addr) gsmtty_modem_update(dlci, 0); @@ -1794,7 +1772,6 @@ static void gsm_queue(struct gsm_mux *gsm) struct gsm_dlci *dlci; u8 cr; int address; - int i, j, k, address_tmp; if (gsm->fcs != GOOD_FCS) { gsm->bad_fcs++; @@ -1826,11 +1803,6 @@ static void gsm_queue(struct gsm_mux *gsm) else { gsm_response(gsm, address, UA|PF); gsm_dlci_open(dlci); - /* Save dlci open address */ - if (address) { - addr_open[addr_cnt] = address; - addr_cnt++; - } } break; case DISC|PF: @@ -1841,33 +1813,8 @@ static void gsm_queue(struct gsm_mux *gsm) return; } /* Real close complete */ - if (!address) { - if (addr_cnt > 0) { - for (i = 0; i < addr_cnt; i++) { - address = addr_open[i]; - dlci = gsm->dlci[address]; - gsm_dlci_close(dlci); - addr_open[i] = 0; - } - } - dlci = gsm->dlci[0]; - gsm_dlci_close(dlci); - addr_cnt = 0; - gsm_response(gsm, 0, UA|PF); - } else { - gsm_response(gsm, address, UA|PF); - gsm_dlci_close(dlci); - /* clear dlci address */ - for (j = 0; j < addr_cnt; j++) { - address_tmp = addr_open[j]; - if (address_tmp == address) { - for (k = j; k < addr_cnt; k++) - addr_open[k] = addr_open[k+1]; - addr_cnt--; - break; - } - } - } + gsm_response(gsm, address, UA|PF); + gsm_dlci_close(dlci); break; case UA|PF: if (cr == 0 || dlci == NULL) @@ -2451,19 +2398,17 @@ static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) else { /* Don't register device 0 - this is the control channel and not a usable tty interface */ - if (gsm->initiator) { - base = mux_num_to_base(gsm); /* Base for this MUX */ - for (i = 1; i < NUM_DLCI; i++) { - struct device *dev; + base = mux_num_to_base(gsm); /* Base for this MUX */ + for (i = 1; i < NUM_DLCI; i++) { + struct device *dev; - dev = tty_register_device(gsm_tty_driver, + dev = tty_register_device(gsm_tty_driver, base + i, NULL); - if (IS_ERR(dev)) { - for (i--; i >= 1; i--) - tty_unregister_device(gsm_tty_driver, - base + i); - return PTR_ERR(dev); - } + if (IS_ERR(dev)) { + for (i--; i >= 1; i--) + tty_unregister_device(gsm_tty_driver, + base + i); + return PTR_ERR(dev); } } } @@ -2485,10 +2430,8 @@ static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) int i; WARN_ON(tty != gsm->tty); - if (gsm->initiator) { - for (i = 1; i < NUM_DLCI; i++) - tty_unregister_device(gsm_tty_driver, base + i); - } + for (i = 1; i < NUM_DLCI; i++) + tty_unregister_device(gsm_tty_driver, base + i); tty_kref_put(gsm->tty); gsm->tty = NULL; }

3 years, 7 months

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FAILED: patch "[PATCH] tty: n_gsm: fix broken virtual tty handling" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

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 a8c5b8255f8a9acd58a4b15ff1c14cd6effd114b Mon Sep 17 00:00:00 2001 From: Daniel Starke <daniel.starke(a)siemens.com> Date: Fri, 22 Apr 2022 00:10:23 -0700 Subject: [PATCH] tty: n_gsm: fix broken virtual tty handling Dynamic virtual tty registration was introduced to allow the user to handle these cases with uevent rules. The following commits relate to this: Commit 5b87686e3203 ("tty: n_gsm: Modify gsmtty driver register method when config requester") Commit 0b91b5332368 ("tty: n_gsm: Save dlci address open status when config requester") Commit 46292622ad73 ("tty: n_gsm: clean up indenting in gsm_queue()") However, the following behavior can be seen with this implementation: - n_gsm ldisc is activated via ioctl - all configuration parameters are set to their default value (initiator=0) - the mux gets activated and attached and gsmtty0 is being registered in in gsm_dlci_open() after DLCI 0 was established (DLCI 0 is the control channel) - the user configures n_gsm via ioctl GSMIOC_SETCONF as initiator - this re-attaches the n_gsm mux - no new gsmtty devices are registered in gsmld_attach_gsm() because the mux is already active - the initiator side registered only the control channel as gsmtty0 (which should never happen) and no user channel tty The commits above make it impossible to operate the initiator side as no user channel tty is or will be available. On the other hand, this behavior will make it also impossible to allow DLCI parameter negotiation on responder side in the future. The responder side first needs to provide a device for the application before the application can set its parameters of the associated DLCI via ioctl. Note that the user application is still able to detect a link establishment without relaying to uevent by waiting for DTR open on responder side. This is the same behavior as on a physical serial interface. And on initiator side a tty hangup can be detected if a link establishment request failed. Revert the commits above completely to always register all user channels and no control channel after mux attachment. No other changes are made. Fixes: 5b87686e3203 ("tty: n_gsm: Modify gsmtty driver register method when config requester") Cc: stable(a)vger.kernel.org Signed-off-by: Daniel Starke <daniel.starke(a)siemens.com> Link: https://lore.kernel.org/r/20220422071025.5490-1-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 979dc9151383..99fe54247a87 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -272,10 +272,6 @@ static DEFINE_SPINLOCK(gsm_mux_lock); static struct tty_driver *gsm_tty_driver; -/* Save dlci open address */ -static int addr_open[256] = { 0 }; -/* Save dlci open count */ -static int addr_cnt; /* * This section of the driver logic implements the GSM encodings * both the basic and the 'advanced'. Reliable transport is not @@ -1185,7 +1181,6 @@ static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen) } static void gsm_dlci_begin_close(struct gsm_dlci *dlci); -static void gsm_dlci_close(struct gsm_dlci *dlci); /** * gsm_control_message - DLCI 0 control processing @@ -1204,28 +1199,15 @@ static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, { u8 buf[1]; unsigned long flags; - struct gsm_dlci *dlci; - int i; - int address; switch (command) { case CMD_CLD: { - if (addr_cnt > 0) { - for (i = 0; i < addr_cnt; i++) { - address = addr_open[i]; - dlci = gsm->dlci[address]; - gsm_dlci_close(dlci); - addr_open[i] = 0; - } - } + struct gsm_dlci *dlci = gsm->dlci[0]; /* Modem wishes to close down */ - dlci = gsm->dlci[0]; if (dlci) { dlci->dead = true; gsm->dead = true; - gsm_dlci_close(dlci); - addr_cnt = 0; - gsm_response(gsm, 0, UA|PF); + gsm_dlci_begin_close(dlci); } } break; @@ -1459,8 +1441,6 @@ static void gsm_dlci_close(struct gsm_dlci *dlci) wake_up_interruptible(&dlci->port.open_wait); } else dlci->gsm->dead = true; - /* Unregister gsmtty driver,report gsmtty dev remove uevent for user */ - tty_unregister_device(gsm_tty_driver, dlci->addr); wake_up(&dlci->gsm->event); /* A DLCI 0 close is a MUX termination so we need to kick that back to userspace somehow */ @@ -1482,8 +1462,6 @@ static void gsm_dlci_open(struct gsm_dlci *dlci) dlci->state = DLCI_OPEN; if (debug & 8) pr_debug("DLCI %d goes open.\n", dlci->addr); - /* Register gsmtty driver,report gsmtty dev add uevent for user */ - tty_register_device(gsm_tty_driver, dlci->addr, NULL); /* Send current modem state */ if (dlci->addr) gsmtty_modem_update(dlci, 0); @@ -1794,7 +1772,6 @@ static void gsm_queue(struct gsm_mux *gsm) struct gsm_dlci *dlci; u8 cr; int address; - int i, j, k, address_tmp; if (gsm->fcs != GOOD_FCS) { gsm->bad_fcs++; @@ -1826,11 +1803,6 @@ static void gsm_queue(struct gsm_mux *gsm) else { gsm_response(gsm, address, UA|PF); gsm_dlci_open(dlci); - /* Save dlci open address */ - if (address) { - addr_open[addr_cnt] = address; - addr_cnt++; - } } break; case DISC|PF: @@ -1841,33 +1813,8 @@ static void gsm_queue(struct gsm_mux *gsm) return; } /* Real close complete */ - if (!address) { - if (addr_cnt > 0) { - for (i = 0; i < addr_cnt; i++) { - address = addr_open[i]; - dlci = gsm->dlci[address]; - gsm_dlci_close(dlci); - addr_open[i] = 0; - } - } - dlci = gsm->dlci[0]; - gsm_dlci_close(dlci); - addr_cnt = 0; - gsm_response(gsm, 0, UA|PF); - } else { - gsm_response(gsm, address, UA|PF); - gsm_dlci_close(dlci); - /* clear dlci address */ - for (j = 0; j < addr_cnt; j++) { - address_tmp = addr_open[j]; - if (address_tmp == address) { - for (k = j; k < addr_cnt; k++) - addr_open[k] = addr_open[k+1]; - addr_cnt--; - break; - } - } - } + gsm_response(gsm, address, UA|PF); + gsm_dlci_close(dlci); break; case UA|PF: if (cr == 0 || dlci == NULL) @@ -2451,19 +2398,17 @@ static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) else { /* Don't register device 0 - this is the control channel and not a usable tty interface */ - if (gsm->initiator) { - base = mux_num_to_base(gsm); /* Base for this MUX */ - for (i = 1; i < NUM_DLCI; i++) { - struct device *dev; + base = mux_num_to_base(gsm); /* Base for this MUX */ + for (i = 1; i < NUM_DLCI; i++) { + struct device *dev; - dev = tty_register_device(gsm_tty_driver, + dev = tty_register_device(gsm_tty_driver, base + i, NULL); - if (IS_ERR(dev)) { - for (i--; i >= 1; i--) - tty_unregister_device(gsm_tty_driver, - base + i); - return PTR_ERR(dev); - } + if (IS_ERR(dev)) { + for (i--; i >= 1; i--) + tty_unregister_device(gsm_tty_driver, + base + i); + return PTR_ERR(dev); } } } @@ -2485,10 +2430,8 @@ static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) int i; WARN_ON(tty != gsm->tty); - if (gsm->initiator) { - for (i = 1; i < NUM_DLCI; i++) - tty_unregister_device(gsm_tty_driver, base + i); - } + for (i = 1; i < NUM_DLCI; i++) + tty_unregister_device(gsm_tty_driver, base + i); tty_kref_put(gsm->tty); gsm->tty = NULL; }

3 years, 7 months

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FAILED: patch "[PATCH] tty: n_gsm: fix broken virtual tty handling" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

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 a8c5b8255f8a9acd58a4b15ff1c14cd6effd114b Mon Sep 17 00:00:00 2001 From: Daniel Starke <daniel.starke(a)siemens.com> Date: Fri, 22 Apr 2022 00:10:23 -0700 Subject: [PATCH] tty: n_gsm: fix broken virtual tty handling Dynamic virtual tty registration was introduced to allow the user to handle these cases with uevent rules. The following commits relate to this: Commit 5b87686e3203 ("tty: n_gsm: Modify gsmtty driver register method when config requester") Commit 0b91b5332368 ("tty: n_gsm: Save dlci address open status when config requester") Commit 46292622ad73 ("tty: n_gsm: clean up indenting in gsm_queue()") However, the following behavior can be seen with this implementation: - n_gsm ldisc is activated via ioctl - all configuration parameters are set to their default value (initiator=0) - the mux gets activated and attached and gsmtty0 is being registered in in gsm_dlci_open() after DLCI 0 was established (DLCI 0 is the control channel) - the user configures n_gsm via ioctl GSMIOC_SETCONF as initiator - this re-attaches the n_gsm mux - no new gsmtty devices are registered in gsmld_attach_gsm() because the mux is already active - the initiator side registered only the control channel as gsmtty0 (which should never happen) and no user channel tty The commits above make it impossible to operate the initiator side as no user channel tty is or will be available. On the other hand, this behavior will make it also impossible to allow DLCI parameter negotiation on responder side in the future. The responder side first needs to provide a device for the application before the application can set its parameters of the associated DLCI via ioctl. Note that the user application is still able to detect a link establishment without relaying to uevent by waiting for DTR open on responder side. This is the same behavior as on a physical serial interface. And on initiator side a tty hangup can be detected if a link establishment request failed. Revert the commits above completely to always register all user channels and no control channel after mux attachment. No other changes are made. Fixes: 5b87686e3203 ("tty: n_gsm: Modify gsmtty driver register method when config requester") Cc: stable(a)vger.kernel.org Signed-off-by: Daniel Starke <daniel.starke(a)siemens.com> Link: https://lore.kernel.org/r/20220422071025.5490-1-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 979dc9151383..99fe54247a87 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -272,10 +272,6 @@ static DEFINE_SPINLOCK(gsm_mux_lock); static struct tty_driver *gsm_tty_driver; -/* Save dlci open address */ -static int addr_open[256] = { 0 }; -/* Save dlci open count */ -static int addr_cnt; /* * This section of the driver logic implements the GSM encodings * both the basic and the 'advanced'. Reliable transport is not @@ -1185,7 +1181,6 @@ static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen) } static void gsm_dlci_begin_close(struct gsm_dlci *dlci); -static void gsm_dlci_close(struct gsm_dlci *dlci); /** * gsm_control_message - DLCI 0 control processing @@ -1204,28 +1199,15 @@ static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, { u8 buf[1]; unsigned long flags; - struct gsm_dlci *dlci; - int i; - int address; switch (command) { case CMD_CLD: { - if (addr_cnt > 0) { - for (i = 0; i < addr_cnt; i++) { - address = addr_open[i]; - dlci = gsm->dlci[address]; - gsm_dlci_close(dlci); - addr_open[i] = 0; - } - } + struct gsm_dlci *dlci = gsm->dlci[0]; /* Modem wishes to close down */ - dlci = gsm->dlci[0]; if (dlci) { dlci->dead = true; gsm->dead = true; - gsm_dlci_close(dlci); - addr_cnt = 0; - gsm_response(gsm, 0, UA|PF); + gsm_dlci_begin_close(dlci); } } break; @@ -1459,8 +1441,6 @@ static void gsm_dlci_close(struct gsm_dlci *dlci) wake_up_interruptible(&dlci->port.open_wait); } else dlci->gsm->dead = true; - /* Unregister gsmtty driver,report gsmtty dev remove uevent for user */ - tty_unregister_device(gsm_tty_driver, dlci->addr); wake_up(&dlci->gsm->event); /* A DLCI 0 close is a MUX termination so we need to kick that back to userspace somehow */ @@ -1482,8 +1462,6 @@ static void gsm_dlci_open(struct gsm_dlci *dlci) dlci->state = DLCI_OPEN; if (debug & 8) pr_debug("DLCI %d goes open.\n", dlci->addr); - /* Register gsmtty driver,report gsmtty dev add uevent for user */ - tty_register_device(gsm_tty_driver, dlci->addr, NULL); /* Send current modem state */ if (dlci->addr) gsmtty_modem_update(dlci, 0); @@ -1794,7 +1772,6 @@ static void gsm_queue(struct gsm_mux *gsm) struct gsm_dlci *dlci; u8 cr; int address; - int i, j, k, address_tmp; if (gsm->fcs != GOOD_FCS) { gsm->bad_fcs++; @@ -1826,11 +1803,6 @@ static void gsm_queue(struct gsm_mux *gsm) else { gsm_response(gsm, address, UA|PF); gsm_dlci_open(dlci); - /* Save dlci open address */ - if (address) { - addr_open[addr_cnt] = address; - addr_cnt++; - } } break; case DISC|PF: @@ -1841,33 +1813,8 @@ static void gsm_queue(struct gsm_mux *gsm) return; } /* Real close complete */ - if (!address) { - if (addr_cnt > 0) { - for (i = 0; i < addr_cnt; i++) { - address = addr_open[i]; - dlci = gsm->dlci[address]; - gsm_dlci_close(dlci); - addr_open[i] = 0; - } - } - dlci = gsm->dlci[0]; - gsm_dlci_close(dlci); - addr_cnt = 0; - gsm_response(gsm, 0, UA|PF); - } else { - gsm_response(gsm, address, UA|PF); - gsm_dlci_close(dlci); - /* clear dlci address */ - for (j = 0; j < addr_cnt; j++) { - address_tmp = addr_open[j]; - if (address_tmp == address) { - for (k = j; k < addr_cnt; k++) - addr_open[k] = addr_open[k+1]; - addr_cnt--; - break; - } - } - } + gsm_response(gsm, address, UA|PF); + gsm_dlci_close(dlci); break; case UA|PF: if (cr == 0 || dlci == NULL) @@ -2451,19 +2398,17 @@ static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) else { /* Don't register device 0 - this is the control channel and not a usable tty interface */ - if (gsm->initiator) { - base = mux_num_to_base(gsm); /* Base for this MUX */ - for (i = 1; i < NUM_DLCI; i++) { - struct device *dev; + base = mux_num_to_base(gsm); /* Base for this MUX */ + for (i = 1; i < NUM_DLCI; i++) { + struct device *dev; - dev = tty_register_device(gsm_tty_driver, + dev = tty_register_device(gsm_tty_driver, base + i, NULL); - if (IS_ERR(dev)) { - for (i--; i >= 1; i--) - tty_unregister_device(gsm_tty_driver, - base + i); - return PTR_ERR(dev); - } + if (IS_ERR(dev)) { + for (i--; i >= 1; i--) + tty_unregister_device(gsm_tty_driver, + base + i); + return PTR_ERR(dev); } } } @@ -2485,10 +2430,8 @@ static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) int i; WARN_ON(tty != gsm->tty); - if (gsm->initiator) { - for (i = 1; i < NUM_DLCI; i++) - tty_unregister_device(gsm_tty_driver, base + i); - } + for (i = 1; i < NUM_DLCI; i++) + tty_unregister_device(gsm_tty_driver, base + i); tty_kref_put(gsm->tty); gsm->tty = NULL; }

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