From e9036d0662360cd4c79578565ce422ed5872f301 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Fri, 5 Feb 2016 10:49:36 -0800 Subject: [PATCH 1/8] tty: Drop krefs for interrupted tty lock When the tty lock is interrupted on attempted re-open, 2 tty krefs are still held. Drop extra kref before returning failure from tty_lock_interruptible(), and drop lookup kref before returning failure from tty_open(). Fixes: 0bfd464d3fdd ("tty: Wait interruptibly for tty lock on reopen") Reported-by: Dmitry Vyukov Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_io.c | 3 +-- drivers/tty/tty_mutex.c | 7 ++++++- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 5cec01c75691..a7eacef1bd22 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -2066,13 +2066,12 @@ retry_open: if (tty) { mutex_unlock(&tty_mutex); retval = tty_lock_interruptible(tty); + tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */ if (retval) { if (retval == -EINTR) retval = -ERESTARTSYS; goto err_unref; } - /* safe to drop the kref from tty_driver_lookup_tty() */ - tty_kref_put(tty); retval = tty_reopen(tty); if (retval < 0) { tty_unlock(tty); diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c index d2f3c4cd697f..dfa9ec03fa8e 100644 --- a/drivers/tty/tty_mutex.c +++ b/drivers/tty/tty_mutex.c @@ -21,10 +21,15 @@ EXPORT_SYMBOL(tty_lock); int tty_lock_interruptible(struct tty_struct *tty) { + int ret; + if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty)) return -EIO; tty_kref_get(tty); - return mutex_lock_interruptible(&tty->legacy_mutex); + ret = mutex_lock_interruptible(&tty->legacy_mutex); + if (ret) + tty_kref_put(tty); + return ret; } void __lockfunc tty_unlock(struct tty_struct *tty) From d56edd7ed0ed46a8043ee3040ededbd190818ccf Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 13 Jan 2016 23:33:59 +0100 Subject: [PATCH 2/8] 8250: uniphier: allow modular build with 8250 console The recently added uniphier 8250 port driver supports early console probing, and it supports being built as a module, but the combination of the two fails to link: ERROR: "early_serial8250_setup" [drivers/tty/serial/8250/8250_uniphier.ko] undefined! Given that earlycon support in a loadable module makes no sense, making that code conditional on 'MODULE' is a correct solution. Signed-off-by: Arnd Bergmann Fixes: b8d20e06eaad ("serial: 8250_uniphier: add earlycon support") Acked-by: Masahiro Yamada Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_uniphier.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/8250/8250_uniphier.c b/drivers/tty/serial/8250/8250_uniphier.c index bab6b3ae2540..1b7bd26555b7 100644 --- a/drivers/tty/serial/8250/8250_uniphier.c +++ b/drivers/tty/serial/8250/8250_uniphier.c @@ -35,7 +35,7 @@ struct uniphier8250_priv { spinlock_t atomic_write_lock; }; -#ifdef CONFIG_SERIAL_8250_CONSOLE +#if defined(CONFIG_SERIAL_8250_CONSOLE) && !defined(MODULE) static int __init uniphier_early_console_setup(struct earlycon_device *device, const char *options) { From 308bbc9ab838d0ace0298268c7970ba9513e2c65 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Tue, 12 Jan 2016 15:14:46 -0800 Subject: [PATCH 3/8] serial: omap: Prevent DoS using unprivileged ioctl(TIOCSRS485) The omap-serial driver emulates RS485 delays using software timers, but neglects to clamp the input values from the unprivileged ioctl(TIOCSRS485). Because the software implementation busy-waits, malicious userspace could stall the cpu for ~49 days. Clamp the input values to < 100ms. Fixes: 4a0ac0f55b18 ("OMAP: add RS485 support") Cc: # 3.12+ Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/omap-serial.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c index b645f9228ed7..27d3b978f16e 100644 --- a/drivers/tty/serial/omap-serial.c +++ b/drivers/tty/serial/omap-serial.c @@ -1343,7 +1343,7 @@ static inline void serial_omap_add_console_port(struct uart_omap_port *up) /* Enable or disable the rs485 support */ static int -serial_omap_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf) +serial_omap_config_rs485(struct uart_port *port, struct serial_rs485 *rs485) { struct uart_omap_port *up = to_uart_omap_port(port); unsigned int mode; @@ -1356,8 +1356,12 @@ serial_omap_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf) up->ier = 0; serial_out(up, UART_IER, 0); + /* Clamp the delays to [0, 100ms] */ + rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U); + rs485->delay_rts_after_send = min(rs485->delay_rts_after_send, 100U); + /* store new config */ - port->rs485 = *rs485conf; + port->rs485 = *rs485; /* * Just as a precaution, only allow rs485 From b4a512b8bf7185787e291cddad3b6457b2367120 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 13 Jan 2016 21:59:23 +0100 Subject: [PATCH 4/8] serial/omap: mark wait_for_xmitr as __maybe_unused The wait_for_xmitr() function is only used if CONFIG_CONSOLE_POLL or CONFIG_SERIAL_OMAP_CONSOLE are set, but when both are disabled, the compiler warns about it being unused: drivers/tty/serial/omap-serial.c:1168:13: warning: 'wait_for_xmitr' defined but not used [-Wunused-func We could add more #ifdefs to work around it, but adding __maybe_unused seems nicer. Signed-off-by: Arnd Bergmann Fixes: 2172076d2399 ("serial/omap-serial: Deinline wait_for_xmitr, save 165 bytes") Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/omap-serial.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c index 27d3b978f16e..fa49eb1e2fa2 100644 --- a/drivers/tty/serial/omap-serial.c +++ b/drivers/tty/serial/omap-serial.c @@ -1165,7 +1165,7 @@ serial_omap_type(struct uart_port *port) #define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE) -static void wait_for_xmitr(struct uart_omap_port *up) +static void __maybe_unused wait_for_xmitr(struct uart_omap_port *up) { unsigned int status, tmout = 10000; From 7dde55787b43a8f2b4021916db38d90c03a2ec64 Mon Sep 17 00:00:00 2001 From: Jeremy McNicoll Date: Tue, 2 Feb 2016 13:00:45 -0800 Subject: [PATCH 5/8] tty: Add support for PCIe WCH382 2S multi-IO card WCH382 2S board is a PCIe card with 2 DB9 COM ports detected as Serial controller: Device 1c00:3253 (rev 10) (prog-if 05 [16850]) Signed-off-by: Jeremy McNicoll Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_pci.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c index e71ec78fc11e..7cd6f9a90542 100644 --- a/drivers/tty/serial/8250/8250_pci.c +++ b/drivers/tty/serial/8250/8250_pci.c @@ -1941,6 +1941,7 @@ pci_wch_ch38x_setup(struct serial_private *priv, #define PCIE_VENDOR_ID_WCH 0x1c00 #define PCIE_DEVICE_ID_WCH_CH382_2S1P 0x3250 #define PCIE_DEVICE_ID_WCH_CH384_4S 0x3470 +#define PCIE_DEVICE_ID_WCH_CH382_2S 0x3253 #define PCI_VENDOR_ID_PERICOM 0x12D8 #define PCI_DEVICE_ID_PERICOM_PI7C9X7951 0x7951 @@ -2637,6 +2638,14 @@ static struct pci_serial_quirk pci_serial_quirks[] __refdata = { .subdevice = PCI_ANY_ID, .setup = pci_wch_ch353_setup, }, + /* WCH CH382 2S card (16850 clone) */ + { + .vendor = PCIE_VENDOR_ID_WCH, + .device = PCIE_DEVICE_ID_WCH_CH382_2S, + .subvendor = PCI_ANY_ID, + .subdevice = PCI_ANY_ID, + .setup = pci_wch_ch38x_setup, + }, /* WCH CH382 2S1P card (16850 clone) */ { .vendor = PCIE_VENDOR_ID_WCH, @@ -2955,6 +2964,7 @@ enum pci_board_num_t { pbn_fintek_4, pbn_fintek_8, pbn_fintek_12, + pbn_wch382_2, pbn_wch384_4, pbn_pericom_PI7C9X7951, pbn_pericom_PI7C9X7952, @@ -3775,6 +3785,13 @@ static struct pciserial_board pci_boards[] = { .base_baud = 115200, .first_offset = 0x40, }, + [pbn_wch382_2] = { + .flags = FL_BASE0, + .num_ports = 2, + .base_baud = 115200, + .uart_offset = 8, + .first_offset = 0xC0, + }, [pbn_wch384_4] = { .flags = FL_BASE0, .num_ports = 4, @@ -5574,6 +5591,10 @@ static struct pci_device_id serial_pci_tbl[] = { PCI_ANY_ID, PCI_ANY_ID, 0, 0, pbn_b0_bt_2_115200 }, + { PCIE_VENDOR_ID_WCH, PCIE_DEVICE_ID_WCH_CH382_2S, + PCI_ANY_ID, PCI_ANY_ID, + 0, 0, pbn_wch382_2 }, + { PCIE_VENDOR_ID_WCH, PCIE_DEVICE_ID_WCH_CH384_4S, PCI_ANY_ID, PCI_ANY_ID, 0, 0, pbn_wch384_4 }, From 2831c89f42dcde440cfdccb9fee9f42d54bbc1ef Mon Sep 17 00:00:00 2001 From: "Herton R. Krzesinski" Date: Mon, 11 Jan 2016 12:07:43 -0200 Subject: [PATCH 6/8] pty: fix possible use after free of tty->driver_data This change fixes a bug for a corner case where we have the the last release from a pty master/slave coming from a previously opened /dev/tty file. When this happens, the tty->driver_data can be stale, due to all ptmx or pts/N files having already been closed before (and thus the inode related to these files, which tty->driver_data points to, being already freed/destroyed). The fix here is to keep a reference on the opened master ptmx inode. We maintain the inode referenced until the final pty_unix98_shutdown, and only pass this inode to devpts_kill_index. Signed-off-by: Herton R. Krzesinski Cc: # 2.6.29+ Reviewed-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/pty.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index b3110040164a..3b5cde833ee5 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -681,7 +681,14 @@ static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty) /* this is called once with whichever end is closed last */ static void pty_unix98_shutdown(struct tty_struct *tty) { - devpts_kill_index(tty->driver_data, tty->index); + struct inode *ptmx_inode; + + if (tty->driver->subtype == PTY_TYPE_MASTER) + ptmx_inode = tty->driver_data; + else + ptmx_inode = tty->link->driver_data; + devpts_kill_index(ptmx_inode, tty->index); + iput(ptmx_inode); /* drop reference we acquired at ptmx_open */ } static const struct tty_operations ptm_unix98_ops = { @@ -773,6 +780,15 @@ static int ptmx_open(struct inode *inode, struct file *filp) set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ tty->driver_data = inode; + /* + * In the case where all references to ptmx inode are dropped and we + * still have /dev/tty opened pointing to the master/slave pair (ptmx + * is closed/released before /dev/tty), we must make sure that the inode + * is still valid when we call the final pty_unix98_shutdown, thus we + * hold an additional reference to the ptmx inode + */ + ihold(inode); + tty_add_file(tty, filp); slave_inode = devpts_pty_new(inode, From 1f55c718c290616889c04946864a13ef30f64929 Mon Sep 17 00:00:00 2001 From: "Herton R. Krzesinski" Date: Thu, 14 Jan 2016 17:56:58 -0200 Subject: [PATCH 7/8] pty: make sure super_block is still valid in final /dev/tty close Considering current pty code and multiple devpts instances, it's possible to umount a devpts file system while a program still has /dev/tty opened pointing to a previosuly closed pty pair in that instance. In the case all ptmx and pts/N files are closed, umount can be done. If the program closes /dev/tty after umount is done, devpts_kill_index will use now an invalid super_block, which was already destroyed in the umount operation after running ->kill_sb. This is another "use after free" type of issue, but now related to the allocated super_block instance. To avoid the problem (warning at ida_remove and potential crashes) for this specific case, I added two functions in devpts which grabs additional references to the super_block, which pty code now uses so it makes sure the super block structure is still valid until pty shutdown is done. I also moved the additional inode references to the same functions, which also covered similar case with inode being freed before /dev/tty final close/shutdown. Signed-off-by: Herton R. Krzesinski Cc: stable@vger.kernel.org # 2.6.29+ Reviewed-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/pty.c | 9 ++++++--- fs/devpts/inode.c | 20 ++++++++++++++++++++ include/linux/devpts_fs.h | 4 ++++ 3 files changed, 30 insertions(+), 3 deletions(-) diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index 3b5cde833ee5..2348fa613707 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -688,7 +688,7 @@ static void pty_unix98_shutdown(struct tty_struct *tty) else ptmx_inode = tty->link->driver_data; devpts_kill_index(ptmx_inode, tty->index); - iput(ptmx_inode); /* drop reference we acquired at ptmx_open */ + devpts_del_ref(ptmx_inode); } static const struct tty_operations ptm_unix98_ops = { @@ -785,9 +785,12 @@ static int ptmx_open(struct inode *inode, struct file *filp) * still have /dev/tty opened pointing to the master/slave pair (ptmx * is closed/released before /dev/tty), we must make sure that the inode * is still valid when we call the final pty_unix98_shutdown, thus we - * hold an additional reference to the ptmx inode + * hold an additional reference to the ptmx inode. For the same /dev/tty + * last close case, we also need to make sure the super_block isn't + * destroyed (devpts instance unmounted), before /dev/tty is closed and + * on its release devpts_kill_index is called. */ - ihold(inode); + devpts_add_ref(inode); tty_add_file(tty, filp); diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c index 1f107fd51328..655f21f99160 100644 --- a/fs/devpts/inode.c +++ b/fs/devpts/inode.c @@ -575,6 +575,26 @@ void devpts_kill_index(struct inode *ptmx_inode, int idx) mutex_unlock(&allocated_ptys_lock); } +/* + * pty code needs to hold extra references in case of last /dev/tty close + */ + +void devpts_add_ref(struct inode *ptmx_inode) +{ + struct super_block *sb = pts_sb_from_inode(ptmx_inode); + + atomic_inc(&sb->s_active); + ihold(ptmx_inode); +} + +void devpts_del_ref(struct inode *ptmx_inode) +{ + struct super_block *sb = pts_sb_from_inode(ptmx_inode); + + iput(ptmx_inode); + deactivate_super(sb); +} + /** * devpts_pty_new -- create a new inode in /dev/pts/ * @ptmx_inode: inode of the master diff --git a/include/linux/devpts_fs.h b/include/linux/devpts_fs.h index 251a2090a554..e0ee0b3000b2 100644 --- a/include/linux/devpts_fs.h +++ b/include/linux/devpts_fs.h @@ -19,6 +19,8 @@ int devpts_new_index(struct inode *ptmx_inode); void devpts_kill_index(struct inode *ptmx_inode, int idx); +void devpts_add_ref(struct inode *ptmx_inode); +void devpts_del_ref(struct inode *ptmx_inode); /* mknod in devpts */ struct inode *devpts_pty_new(struct inode *ptmx_inode, dev_t device, int index, void *priv); @@ -32,6 +34,8 @@ void devpts_pty_kill(struct inode *inode); /* Dummy stubs in the no-pty case */ static inline int devpts_new_index(struct inode *ptmx_inode) { return -EINVAL; } static inline void devpts_kill_index(struct inode *ptmx_inode, int idx) { } +static inline void devpts_add_ref(struct inode *ptmx_inode) { } +static inline void devpts_del_ref(struct inode *ptmx_inode) { } static inline struct inode *devpts_pty_new(struct inode *ptmx_inode, dev_t device, int index, void *priv) { From c8053b58762745d93930826b60a4073854a15ce5 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Sun, 7 Feb 2016 18:22:54 -0800 Subject: [PATCH 8/8] Revert "8250: uniphier: allow modular build with 8250 console" This reverts commit d56edd7ed0ed46a8043ee3040ededbd190818ccf, it shouldn't have been applied, it was fixed properly with commit 71f50c6d9a2276f3ec85384bffe2aee1962f4669 ("of: drop symbols declared by _OF_DECLARE() from modules") Reported-by: Masahiro Yamada Cc: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_uniphier.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/8250/8250_uniphier.c b/drivers/tty/serial/8250/8250_uniphier.c index 1b7bd26555b7..bab6b3ae2540 100644 --- a/drivers/tty/serial/8250/8250_uniphier.c +++ b/drivers/tty/serial/8250/8250_uniphier.c @@ -35,7 +35,7 @@ struct uniphier8250_priv { spinlock_t atomic_write_lock; }; -#if defined(CONFIG_SERIAL_8250_CONSOLE) && !defined(MODULE) +#ifdef CONFIG_SERIAL_8250_CONSOLE static int __init uniphier_early_console_setup(struct earlycon_device *device, const char *options) {