kernel/linux.git/drivers/tty, branch v4.19.112

vt: selection, push sel_lock up

2020-03-11T13:15:03+00:00

commit e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2 upstream. sel_lock cannot nest in the console lock. Thanks to syzkaller, the kernel states firmly: > WARNING: possible circular locking dependency detected > 5.6.0-rc3-syzkaller #0 Not tainted > ------------------------------------------------------ > syz-executor.4/20336 is trying to acquire lock: > ffff8880a2e952a0 (&tty->termios_rwsem){++++}, at: tty_unthrottle+0x22/0x100 drivers/tty/tty_ioctl.c:136 > > but task is already holding lock: > ffffffff89462e70 (sel_lock){+.+.}, at: paste_selection+0x118/0x470 drivers/tty/vt/selection.c:374 > > which lock already depends on the new lock. > > the existing dependency chain (in reverse order) is: > > -> #2 (sel_lock){+.+.}: > mutex_lock_nested+0x1b/0x30 kernel/locking/mutex.c:1118 > set_selection_kernel+0x3b8/0x18a0 drivers/tty/vt/selection.c:217 > set_selection_user+0x63/0x80 drivers/tty/vt/selection.c:181 > tioclinux+0x103/0x530 drivers/tty/vt/vt.c:3050 > vt_ioctl+0x3f1/0x3a30 drivers/tty/vt/vt_ioctl.c:364 This is ioctl(TIOCL_SETSEL). Locks held on the path: console_lock -> sel_lock > -> #1 (console_lock){+.+.}: > console_lock+0x46/0x70 kernel/printk/printk.c:2289 > con_flush_chars+0x50/0x650 drivers/tty/vt/vt.c:3223 > n_tty_write+0xeae/0x1200 drivers/tty/n_tty.c:2350 > do_tty_write drivers/tty/tty_io.c:962 [inline] > tty_write+0x5a1/0x950 drivers/tty/tty_io.c:1046 This is write(). Locks held on the path: termios_rwsem -> console_lock > -> #0 (&tty->termios_rwsem){++++}: > down_write+0x57/0x140 kernel/locking/rwsem.c:1534 > tty_unthrottle+0x22/0x100 drivers/tty/tty_ioctl.c:136 > mkiss_receive_buf+0x12aa/0x1340 drivers/net/hamradio/mkiss.c:902 > tty_ldisc_receive_buf+0x12f/0x170 drivers/tty/tty_buffer.c:465 > paste_selection+0x346/0x470 drivers/tty/vt/selection.c:389 > tioclinux+0x121/0x530 drivers/tty/vt/vt.c:3055 > vt_ioctl+0x3f1/0x3a30 drivers/tty/vt/vt_ioctl.c:364 This is ioctl(TIOCL_PASTESEL). Locks held on the path: sel_lock -> termios_rwsem > other info that might help us debug this: > > Chain exists of: > &tty->termios_rwsem --> console_lock --> sel_lock Clearly. From the above, we have: console_lock -> sel_lock sel_lock -> termios_rwsem termios_rwsem -> console_lock Fix this by reversing the console_lock -> sel_lock dependency in ioctl(TIOCL_SETSEL). First, lock sel_lock, then console_lock. Signed-off-by: Jiri Slaby Reported-by: syzbot+26183d9746e62da329b8@syzkaller.appspotmail.com Fixes: 07e6124a1a46 ("vt: selection, close sel_buffer race") Cc: stable Link: https://lore.kernel.org/r/20200228115406.5735-2-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

vt: selection, push console lock down

2020-03-11T13:15:03+00:00

commit 4b70dd57a15d2f4685ac6e38056bad93e81e982f upstream. We need to nest the console lock in sel_lock, so we have to push it down a bit. Fortunately, the callers of set_selection_* just lock the console lock around the function call. So moving it down is easy. In the next patch, we switch the order. Signed-off-by: Jiri Slaby Fixes: 07e6124a1a46 ("vt: selection, close sel_buffer race") Cc: stable Link: https://lore.kernel.org/r/20200228115406.5735-1-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

vt: selection, close sel_buffer race

2020-03-11T13:15:02+00:00

commit 07e6124a1a46b4b5a9b3cacc0c306b50da87abf5 upstream. syzkaller reported this UAF: BUG: KASAN: use-after-free in n_tty_receive_buf_common+0x2481/0x2940 drivers/tty/n_tty.c:1741 Read of size 1 at addr ffff8880089e40e9 by task syz-executor.1/13184 CPU: 0 PID: 13184 Comm: syz-executor.1 Not tainted 5.4.7 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 Call Trace: ... kasan_report+0xe/0x20 mm/kasan/common.c:634 n_tty_receive_buf_common+0x2481/0x2940 drivers/tty/n_tty.c:1741 tty_ldisc_receive_buf+0xac/0x190 drivers/tty/tty_buffer.c:461 paste_selection+0x297/0x400 drivers/tty/vt/selection.c:372 tioclinux+0x20d/0x4e0 drivers/tty/vt/vt.c:3044 vt_ioctl+0x1bcf/0x28d0 drivers/tty/vt/vt_ioctl.c:364 tty_ioctl+0x525/0x15a0 drivers/tty/tty_io.c:2657 vfs_ioctl fs/ioctl.c:47 [inline] It is due to a race between parallel paste_selection (TIOCL_PASTESEL) and set_selection_user (TIOCL_SETSEL) invocations. One uses sel_buffer, while the other frees it and reallocates a new one for another selection. Add a mutex to close this race. The mutex takes care properly of sel_buffer and sel_buffer_lth only. The other selection global variables (like sel_start, sel_end, and sel_cons) are protected only in set_selection_user. The other functions need quite some more work to close the races of the variables there. This is going to happen later. This likely fixes (I am unsure as there is no reproducer provided) bug 206361 too. It was marked as CVE-2020-8648. Signed-off-by: Jiri Slaby Reported-by: syzbot+59997e8d5cbdc486e6f6@syzkaller.appspotmail.com References: https://bugzilla.kernel.org/show_bug.cgi?id=206361 Cc: stable Link: https://lore.kernel.org/r/20200210081131.23572-2-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

serial: 8250_exar: add support for ACCES cards

2020-03-11T13:15:02+00:00

commit 10c5ccc3c6d32f3d7d6c07de1d3f0f4b52f3e3ab upstream. Add ACCES VIDs and PIDs that use the Exar chips Signed-off-by: Jay Dolan Cc: stable Link: https://lore.kernel.org/r/20200305140504.22237-1-jay.dolan@accesio.com Signed-off-by: Greg Kroah-Hartman

tty:serial:mvebu-uart:fix a wrong return

2020-03-11T13:15:01+00:00

commit 4a3e208474204e879d22a310b244cb2f39e5b1f8 upstream. in this place, the function should return a negative value and the PTR_ERR already returns a negative,so return -PTR_ERR() is wrong. Signed-off-by: tangbin Cc: stable Acked-by: Jiri Slaby Link: https://lore.kernel.org/r/20200305013823.20976-1-tangbin@cmss.chinamobile.com Signed-off-by: Greg Kroah-Hartman

serial: ar933x_uart: set UART_CS_{RX,TX}_READY_ORIDE

2020-03-11T13:14:48+00:00

[ Upstream commit 87c5cbf71ecbb9e289d60a2df22eb686c70bf196 ] On AR934x this UART is usually not initialized by the bootloader as it is only used as a secondary serial port while the primary UART is a newly introduced NS16550-compatible. In order to make use of the ar933x-uart on AR934x without RTS/CTS hardware flow control, one needs to set the UART_CS_{RX,TX}_READY_ORIDE bits as other than on AR933x where this UART is used as primary/console, the bootloader on AR934x typically doesn't set those bits. Setting them explicitely on AR933x should not do any harm, so just set them unconditionally. Tested-by: Chuanhong Guo Signed-off-by: Daniel Golle Link: https://lore.kernel.org/r/20200207095335.GA179836@makrotopia.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

sysrq: Remove duplicated sysrq message

2020-03-05T15:42:15+00:00

commit c3fee60908db4a8594f2e4a2131998384b8fa006 upstream. The commit 97f5f0cd8cd0a0544 ("Input: implement SysRq as a separate input handler") added pr_fmt() definition. It caused a duplicated message prefix in the sysrq header messages, for example: [ 177.053931] sysrq: SysRq : Show backtrace of all active CPUs [ 742.864776] sysrq: SysRq : HELP : loglevel(0-9) reboot(b) crash(c) Fixes: 97f5f0cd8cd0a05 ("Input: implement SysRq as a separate input handler") Signed-off-by: Petr Mladek Reviewed-by: Sergey Senozhatsky Cc: Tommi Rantala Signed-off-by: Greg Kroah-Hartman

sysrq: Restore original console_loglevel when sysrq disabled

2020-03-05T15:42:15+00:00

commit 075e1a0c50f59ea210561d0d0fedbd945615df78 upstream. The sysrq header line is printed with an increased loglevel to provide users some positive feedback. The original loglevel is not restored when the sysrq operation is disabled. This bug was introduced in 2.6.12 (pre-git-history) by the commit ("Allow admin to enable only some of the Magic-Sysrq functions"). Signed-off-by: Petr Mladek Reviewed-by: Sergey Senozhatsky Reviewed-by: Steven Rostedt (VMware) Cc: Tommi Rantala Signed-off-by: Greg Kroah-Hartman

tty: serial: qcom_geni_serial: Fix RX cancel command failure

2020-02-28T15:38:55+00:00

[ Upstream commit 679aac5ead2f18d223554a52b543e1195e181811 ] RX cancel command fails when BT is switched on and off multiple times. To handle this, poll for the cancel bit in SE_GENI_S_IRQ_STATUS register instead of SE_GENI_S_CMD_CTRL_REG. As per the HPG update, handle the RX last bit after cancel command and flush out the RX FIFO buffer. Signed-off-by: satya priya Cc: stable Link: https://lore.kernel.org/r/1581415982-8793-1-git-send-email-skakit@codeaurora.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

tty: serial: qcom_geni_serial: Remove xfer_mode variable

2020-02-28T15:38:54+00:00

[ Upstream commit bdc05a8a3f822ca0662464055f902faf760da6be ] The driver only supports FIFO mode so setting and checking this variable is unnecessary. If DMA support is ever added then such checks can be introduced. Signed-off-by: Ryan Case Reviewed-by: Evan Green Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin