BMC/Intel-BMC/linux.git/drivers/tty/tty_io.c, branch dev-4.3

tty: Fix unsafe ldisc reference via ioctl(TIOCGETD)

2016-02-19T22:28:34+00:00

commit 5c17c861a357e9458001f021a7afa7aab9937439 upstream. ioctl(TIOCGETD) retrieves the line discipline id directly from the ldisc because the line discipline id (c_line) in termios is untrustworthy; userspace may have set termios via ioctl(TCSETS*) without actually changing the line discipline via ioctl(TIOCSETD). However, directly accessing the current ldisc via tty->ldisc is unsafe; the ldisc ptr dereferenced may be stale if the line discipline is changing via ioctl(TIOCSETD) or hangup. Wait for the line discipline reference (just like read() or write()) to retrieve the "current" line discipline id. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: Retry failed reopen if tty teardown in-progress

2016-02-19T22:28:34+00:00

commit 7f22f6c935cda600660e623a411fe380015d28d9 upstream. A small window exists where a tty reopen will observe the tty just prior to imminent teardown (tty->count == 0); in this case, open() returns EIO to userspace. Instead, retry the open after checking for signals and yielding; this interruptible retry loop allows teardown to commence and initialize a new tty on retry. Never retry the BSD master pty reopen; there is no guarantee the pty pair teardown is imminent since the slave file descriptors may remain open indefinitely. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: Fix tty_send_xchar() lock order inversion

2015-12-09T19:34:42+00:00

commit ee0c1a65cf95230d5eb3d9de94fd2ead9a428c67 upstream. The correct lock order is atomic_write_lock => termios_rwsem, as established by tty_write() => n_tty_write(). Fixes: c274f6ef1c666 ("tty: Hold termios_rwsem for tcflow(TCIxxx)") Reported-and-Tested-by: Dmitry Vyukov Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

drivers/tty: require read access for controlling terminal

2015-10-04T18:20:30+00:00

This is mostly a hardening fix, given that write-only access to other users' ttys is usually only given through setgid tty executables. Signed-off-by: Jann Horn Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

tty: don't leak cdev in tty_cdev_add()

2015-10-04T17:51:42+00:00

Commit a3a10ce3429e ("Avoid usb reset crashes by making tty_io cdevs truly dynamic") which mixes using cdev_alloc() and cdev_init() is problematic. Subsequent call to cdev_init() after cdev_alloc() sets kobj release method from cdev_dynamic_release() to cdev_default_release() and thus makes it impossible to free allocated cdev. This patch also consolidates error path of cdev_add() as cdev can also leak here if things went wrong. Signed-off-by: Leon Yu Fixes: a3a10ce3429e ("Avoid usb reset crashes by making tty_io cdevs truly dynamic") Acked-by: Richard Watts Signed-off-by: Greg Kroah-Hartman

Avoid usb reset crashes by making tty_io cdevs truly dynamic

2015-08-03T22:24:43+00:00

Avoid usb reset crashes by making tty_io cdevs truly dynamic Signed-off-by: Richard Watts Reported-by: Duncan Mackintosh Signed-off-by: Greg Kroah-Hartman

tty: Replace #ifdef TTY_DEBUG_HANGUP with tty_debug_hangup()

2015-07-24T01:37:31+00:00

Add tty_debug_hangup() macro which uses tty_debug to print the debug message; remove inlined #ifdefs. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: core: Add tty_debug() for printk(KERN_DEBUG) messages

2015-07-24T01:37:31+00:00

Introduce tty_debug() macro to output uniform debug information for tty core debug messages (function name and tty name). Note: printk(KERN_DEBUG) is retained here over pr_debug() since messages can be enabled in non-DEBUG builds. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: core: Improve debug message content

2015-07-24T01:31:29+00:00

Output the function name, tty name, and invariant failure (if applicable). Add the tty count to the tty_open() message. Fix the disassociate_ctty() message, which printed the NULL pointer and the wrong message. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: add missing rcu_read_lock for task_pgrp

2015-07-24T00:56:38+00:00

task_pgrp requires an rcu or tasklist lock to be obtained if the returned pid is to be dereferenced, which kill_pgrp does. Obtain an RCU lock for the duration of use. Signed-off-by: Patrick Donnelly Reviewed-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman