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commit bb2853a6a421a052268eee00fd5d3f6b3504b2b1 upstream.
The ops->receive_buf() may be accessed concurrently from these two
functions. If the driver flushes data to the line discipline
receive_buf() method while tiocsti() is waiting for the
ops->receive_buf() to finish its work, the data race will happen.
For example:
tty_ioctl |tty_ldisc_receive_buf
->tioctsi | ->tty_port_default_receive_buf
| ->tty_ldisc_receive_buf
->hci_uart_tty_receive | ->hci_uart_tty_receive
->h4_recv | ->h4_recv
In this case, the h4 receive buffer will be overwritten by the
latecomer, and we will lost the data.
Hence, change tioctsi() function to use the exclusive lock interface
from tty_buffer to avoid the data race.
Reported-by: syzbot+97388eb9d31b997fe1d0@syzkaller.appspotmail.com
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com>
Link: https://lore.kernel.org/r/20210823000641.2082292-1-phind.uet@gmail.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 1b8b20868a6d64cfe8174a21b25b74367bdf0560 ]
Drivers should return -ENOTTY ("Inappropriate I/O control operation")
when an ioctl isn't supported, while -EINVAL is used for invalid
arguments.
Fix up the TIOCMGET, TIOCMSET and TIOCGICOUNT helpers which returned
-EINVAL when a tty driver did not implement the corresponding
operations.
Note that the TIOCMGET and TIOCMSET helpers predate git and do not get a
corresponding Fixes tag below.
Fixes: d281da7ff6f7 ("tty: Make tiocgicount a handler")
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210407095208.31838-3-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit ddc5fda7456178e2cbc87675b370920d98360daf upstream.
In commit "tty: implement read_iter", I left the read_iter conversion of
the hung up tty case alone, because I incorrectly thought it didn't
matter.
Jiri showed me the errors of my ways, and pointed out the problems with
that incomplete conversion. Fix it all up.
Reported-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/CAHk-=wh+-rGsa=xruEWdg_fJViFG8rN9bpLrfLz=_yBYh2tBhA@mail.gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e71a8d5cf4b4f274740e31b601216071e2a11afa upstream.
When I converted the tty_ldisc_ops 'read()' function to take a kernel
pointer, I was a bit too aggressive about the ldisc returning EOVERFLOW.
Yes, we want to have EOVERFLOW override any partially read data (because
the whole point is that the buffer was too small for the whole packet,
and we don't want to see partial packets), but it shouldn't override a
previous EFAULT.
And in fact, it really is just EOVERFLOW that is special and should
throw away any partially read data, not "any error". Admittedly
EOVERFLOW is currently the only one that can happen for a continuation
read - and if the first read iteration returns an error we won't have this issue.
So this is more of a technicality, but let's just make the intent very
explicit, and re-organize the error handling a bit so that this is all
clearer.
Reported-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/CAHk-=wh+-rGsa=xruEWdg_fJViFG8rN9bpLrfLz=_yBYh2tBhA@mail.gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit dd78b0c483e33225e0e0782b0ed887129b00f956 ]
Now that the ldisc read() function takes kernel pointers, it's fairly
straightforward to make the tty file operations use .read_iter() instead
of .read().
That automatically gives us vread() and friends, and also makes it
possible to do .splice_read() on ttys again.
Fixes: 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops")
Reported-by: Oliver Giles <ohw.giles@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 3b830a9c34d5897be07176ce4e6f2d75e2c8cfd7 ]
The tty line discipline .read() function was passed the final user
pointer destination as an argument, which doesn't match the 'write()'
function, and makes it very inconvenient to do a splice method for
ttys.
This is a conversion to use a kernel buffer instead.
NOTE! It does this by passing the tty line discipline ->read() function
an additional "cookie" to fill in, and an offset into the cookie data.
The line discipline can fill in the cookie data with its own private
information, and then the reader will repeat the read until either the
cookie is cleared or it runs out of data.
The only real user of this is N_HDLC, which can use this to handle big
packets, even if the kernel buffer is smaller than the whole packet.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 3342ff2698e9720f4040cc458a2744b2b32f5c3a upstream.
Al root-caused a new warning from syzbot to the ttyprintk tty driver
returning a write count larger than the data the tty layer actually gave
it. Which confused the tty write code mightily, and with the new
iov_iter based code, caused a WARNING in iov_iter_revert().
syzbot correctly bisected the source of the new warning to commit
9bb48c82aced ("tty: implement write_iter"), but the oddity goes back
much further, it just didn't get caught by anything before.
Reported-by: syzbot+3d2c27c2b7dc2a94814d@syzkaller.appspotmail.com
Fixes: 9bb48c82aced ("tty: implement write_iter")
Debugged-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a9cbbb80e3e7dd38ceac166e0698f161862a18ae upstream.
It turns out that the vfs_iocb_iter_{read,write}() functions are
entirely broken, and don't actually use the passed-in file pointer for
IO - only for the preparatory work (permission checking and for the
write_iter function lookup).
That worked fine for overlayfs, which always builds the new iocb with
the same file pointer that it passes in, but in the general case it ends
up doing nonsensical things (and could cause an iterator call that
doesn't even match the passed-in file pointer).
This subtly broke the tty conversion to write_iter in commit
9bb48c82aced ("tty: implement write_iter"), because the console
redirection didn't actually end up redirecting anything, since the
passed-in file pointer was basically ignored, and the actual write was
done with the original non-redirected console tty after all.
The main visible effect of this is that the console messages were no
longer logged to /var/log/boot.log during graphical boot.
Fix the issue by simply not using the vfs write "helper" function at
all, and just redirecting the write entirely internally to the tty
layer. Do the target writability permission checks when actually
registering the target tty with TIOCCONS instead of at write time.
Fixes: 9bb48c82aced ("tty: implement write_iter")
Reported-and-tested-by: Hans de Goede <hdegoede@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9f12e37cae44a96132fc3031535a0b165486941a upstream.
[ Also moved the declaration of redirected_tty_write() to the proper
location in a header file. The reason for the bug was the bogus extern
declaration in n_tty.c silently not matching the changed definition in
tty_io.c, and because it wasn't in a shared header file, there was no
cross-checking of the declaration.
Sami noticed because Clang's Control Flow Integrity checking ended up
incidentally noticing the inconsistent declaration. - Linus ]
Fixes: 9bb48c82aced ("tty: implement write_iter")
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 17749851eb9ca2298e7c3b81aae4228961b36f28 upstream.
In commit "tty: implement write_iter", I left the write_iter conversion
of the hung up tty case alone, because I incorrectly thought it didn't
matter.
Jiri showed me the errors of my ways, and pointed out the problems with
that incomplete conversion. Fix it all up.
Reported-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/CAHk-=wh+-rGsa=xruEWdg_fJViFG8rN9bpLrfLz=_yBYh2tBhA@mail.gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9bb48c82aced07698a2d08ee0f1475a6c4f6b266 upstream.
This makes the tty layer use the .write_iter() function instead of the
traditional .write() functionality.
That allows writev(), but more importantly also makes it possible to
enable .splice_write() for ttys, reinstating the "splice to tty"
functionality that was lost in commit 36e2c7421f02 ("fs: don't allow
splice read/write without explicit ops").
Fixes: 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops")
Reported-by: Oliver Giles <ohw.giles@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, locking of ->session is very inconsistent; most places
protect it using the legacy tty mutex, but disassociate_ctty(),
__do_SAK(), tiocspgrp() and tiocgsid() don't.
Two of the writers hold the ctrl_lock (because they already need it for
->pgrp), but __proc_set_tty() doesn't do that yet.
On a PREEMPT=y system, an unprivileged user can theoretically abuse
this broken locking to read 4 bytes of freed memory via TIOCGSID if
tiocgsid() is preempted long enough at the right point. (Other things
might also go wrong, especially if root-only ioctls are involved; I'm
not sure about that.)
Change the locking on ->session such that:
- tty_lock() is held by all writers: By making disassociate_ctty()
hold it. This should be fine because the same lock can already be
taken through the call to tty_vhangup_session().
The tricky part is that we need to shorten the area covered by
siglock to be able to take tty_lock() without ugly retry logic; as
far as I can tell, this should be fine, since nothing in the
signal_struct is touched in the `if (tty)` branch.
- ctrl_lock is held by all writers: By changing __proc_set_tty() to
hold the lock a little longer.
- All readers that aren't holding tty_lock() hold ctrl_lock: By
adding locking to tiocgsid() and __do_SAK(), and expanding the area
covered by ctrl_lock in tiocspgrp().
Cc: stable@kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 2ae0b31e0face ("tty: don't crash in tty_init_dev when missing
tty_port") didn't fully prevent the crash as the cleanup path in
tty_init_dev() calls release_tty() which dereferences tty->port
without checking it for non-null.
Add tty->port checks to release_tty to avoid the kernel crash.
Fixes: 2ae0b31e0face ("tty: don't crash in tty_init_dev when missing tty_port")
Signed-off-by: Matthias Reichl <hias@horus.com>
Link: https://lore.kernel.org/r/20201105123432.4448-1-hias@horus.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
With W=1, the kernel-doc checker complains quite a lot in the tty layer.
Over the time, many documented parameters were renamed, removed or
switched from tty to tty_port and similar. Some were mistyped in the doc
too.
So fix all these in the tty core. (But do not add the missing ones which
the checker complains about too. Not now.) The rest in the tty layer
will follow in the next patches.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200818085655.12071-4-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use the preferred form for passing the size of a structure type. The
alternative form where the structure type is spelled out hurts
readability and introduces an opportunity for a bug when the object
type is changed but the corresponding object identifier to which the
sizeof operator is applied is not.
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/b04dd8cdd67bd6ffde3fd12940aeef35fdb824a6.1595543280.git.gustavoars@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix the following checkpatch.pl warnings together with all the
identation issues in struct serial_struct32:
ERROR: code indent should use tabs where possible
+ char reserved_char;$
WARNING: please, no spaces at the start of a line
+ char reserved_char;$
ERROR: code indent should use tabs where possible
+ compat_int_t reserved;$
WARNING: please, no spaces at the start of a line
+ compat_int_t reserved;$
Acked-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/77576843397aeab0af8aa0423a9768f3ca8dedfb.1595543280.git.gustavoars@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 77654350306a ("take compat TIOC[SG]SERIAL treatment into
tty_compat_ioctl()") changed the compat version of TIOCGSERIAL to start
checking for the presence of the ->set_serial function pointer rather
than ->get_serial. This appears to be a copy-and-paste error, since
->get_serial is the function pointer that is called as well as the
pointer that is checked by the non-compat version of TIOCGSERIAL.
Fix this by checking the correct function pointer.
Fixes: 77654350306a ("take compat TIOC[SG]SERIAL treatment into tty_compat_ioctl()")
Cc: <stable@vger.kernel.org> # v4.20+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200224182044.234553-3-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 77654350306a ("take compat TIOC[SG]SERIAL treatment into
tty_compat_ioctl()") changed the compat version of TIOCGSERIAL to start
copying a whole 'serial_struct32' to userspace rather than individual
fields, but failed to initialize all padding and fields -- namely the
hole after the 'iomem_reg_shift' field, and the 'reserved' field.
Fix this by initializing the struct to zero.
[v2: use sizeof, and convert the adjacent line for consistency.]
Reported-by: syzbot+8da9175e28eadcb203ce@syzkaller.appspotmail.com
Fixes: 77654350306a ("take compat TIOC[SG]SERIAL treatment into tty_compat_ioctl()")
Cc: <stable@vger.kernel.org> # v4.20+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200224182044.234553-2-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The current version of the TTY code unlocks the tty_struct(s) before
release_tty() rather than after. Moreover, tty_unlock_pair() no longer
exists. Thus, remove the outdated comments regarding tty_unlock_pair().
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20200224073359.292795-1-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The driver variable is assigned to unconditionally and not used before.
So there is no need to explicitly initialize it at the start of
tty_kopen().
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20191217075040.8020-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Here is the "big" tty and serial driver patches for 5.5-rc1. It's a bit
later in the merge window than normal as I wanted to make sure some
last-minute patches applied to it were all sane. They seem to be :)
There's a lot of little stuff in here, for the tty core, and for lots of
serial drivers:
- reverts of uartlite serial driver patches that were wrong
- msm-serial driver fixes
- serial core updates and fixes
- tty core fixes
- serial driver dma mapping api changes
- lots of other tiny fixes and updates for serial drivers
All of these have been in linux-next for a while with no reported
issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial updates from Greg KH:
"Here is the "big" tty and serial driver patches for 5.5-rc1.
It's a bit later in the merge window than normal as I wanted to make
sure some last-minute patches applied to it were all sane. They seem
to be :)
There's a lot of little stuff in here, for the tty core, and for lots
of serial drivers:
- reverts of uartlite serial driver patches that were wrong
- msm-serial driver fixes
- serial core updates and fixes
- tty core fixes
- serial driver dma mapping api changes
- lots of other tiny fixes and updates for serial drivers
All of these have been in linux-next for a while with no reported
issues"
* tag 'tty-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (58 commits)
Revert "serial/8250: Add support for NI-Serial PXI/PXIe+485 devices"
vcs: prevent write access to vcsu devices
tty: vt: keyboard: reject invalid keycodes
tty: don't crash in tty_init_dev when missing tty_port
serial: stm32: fix clearing interrupt error flags
tty: Fix Kconfig indentation, continued
serial: serial_core: Perform NULL checks for break_ctl ops
tty: remove unused argument from tty_open_by_driver()
tty: Fix Kconfig indentation
{tty: serial, nand: onenand}: samsung: rename to fix build warning
serial: ifx6x60: add missed pm_runtime_disable
serial: pl011: Fix DMA ->flush_buffer()
Revert "serial-uartlite: Move the uart register"
Revert "serial-uartlite: Add get serial id if not provided"
Revert "serial-uartlite: Do not use static struct uart_driver out of probe()"
Revert "serial-uartlite: Add runtime support"
Revert "serial-uartlite: Change logic how console_port is setup"
Revert "serial-uartlite: Use allocated structure instead of static ones"
tty: serial: msm_serial: Use dma_request_chan() directly for channel request
tty: serial: tegra: Use dma_request_chan() directly for channel request
...
We currently warn the user when tty->port is not set in tty_init_dev
yet. The warning says that the kernel will crash later. And it really
will only few lines below at:
tty->port->itty = tty;
So be nice and avoid the crash -- return an error instead. And update
the warning.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Link: https://lore.kernel.org/r/20191122101721.7222-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The argument 'inode' passed to tty_open_by_driver() was not being used.
Remove the extra argument.
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Link: https://lore.kernel.org/r/20191120151709.14148-1-sudipm.mukherjee@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Multiple tty devices are have tty devices that handle the
PPPIOCGUNIT and PPPIOCGCHAN ioctls. To avoid adding a compat_ioctl
handler to each of those, add it directly in tty_compat_ioctl
so we can remove the calls from fs/compat_ioctl.c.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
All users of this call are in socket or tty code, so handling
it there means we can avoid the table entry in fs/compat_ioctl.c.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: netdev@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Add a helper to match a device by its type and provide wrappers
for {bus/class/driver}_find_device() APIs.
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-usb@vger.kernel.org
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Tomas Winkler <tomas.winkler@intel.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20190723221838.12024-5-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_lookup_driver take a reference to the struct tty_driver, but forget
to release it on the error path, lead to a memory leak.
add a tty_driver_kref_put before error return.
Signed-off-by: Lin Yi <teroincn@163.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Update an obsolete comment referring to the termios_locked structure
which was removed over a decade ago by commit fe6e29fdb1a7 ("tty:
simplify ktermios allocation").
While at it, fix the "Thus" typo.
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit b9ca5f8560af244489b4a1bc1ae88b341f24bc95 as 0-day
shows it has a circular locking dependency.
Fixes: b9ca5f8560af ("tty: pty: Fix race condition between release_one_tty and pty_write")
Reported-by: kernel test robot <lkp@intel.com>
Cc: Sahara <keun-o.park@darkmatter.ae>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Especially when a linked tty is used such as pty, the linked tty
port's buf works have not been cancelled while master tty port's
buf work has been cancelled. Since release_one_tty and flush_to_ldisc
run in workqueue threads separately, when pty_cleanup happens and
link tty port is freed, flush_to_ldisc tries to access freed port
and port->itty, eventually it causes a panic.
This patch utilizes the magic value with holding the tty_mutex to
check if the tty->link is valid.
Fixes: 2b022ab7542d ("pty: cancel pty slave port buf's work in tty_release")
Signed-off-by: Sahara <keun-o.park@darkmatter.ae>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
By default, the kernel will automatically load the module of any line
dicipline that is asked for. As this sometimes isn't the safest thing
to do, provide a sysctl to disable this feature.
By default, we set this to 'y' as that is the historical way that Linux
has worked, and we do not want to break working systems. But in the
future, perhaps this can default to 'n' to prevent this functionality.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Some tty line disciplines do not have a receive buf callback, so
properly check for that before calling it. If they do not have this
callback, just eat the character quietly, as we can't fail this call.
Reported-by: Jann Horn <jannh@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Try to get reference for ldisc during tty_reopen().
If ldisc present, we don't need to do tty_ldisc_reinit() and lock the
write side for line discipline semaphore.
Effectively, it optimizes fast-path for tty_reopen(), but more
importantly it won't interrupt ongoing IO on the tty as no ldisc change
is needed.
Fixes user-visible issue when tty_reopen() interrupted login process for
user with a long password, observed and reported by Lukas.
Fixes: c96cf923a98d ("tty: Don't block on IO when ldisc change is pending")
Fixes: 83d817f41070 ("tty: Hold tty_ldisc_lock() during tty_reopen()")
Cc: Jiri Slaby <jslaby@suse.com>
Reported-by: Lukas F. Hartmann <lukas@mntmn.com>
Tested-by: Lukas F. Hartmann <lukas@mntmn.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_ldisc_reinit() doesn't race with neither tty_ldisc_hangup()
nor set_ldisc() nor tty_ldisc_release() as they use tty lock.
But it races with anyone who expects line discipline to be the same
after hoding read semaphore in tty_ldisc_ref().
We've seen the following crash on v4.9.108 stable:
BUG: unable to handle kernel paging request at 0000000000002260
IP: [..] n_tty_receive_buf_common+0x5f/0x86d
Workqueue: events_unbound flush_to_ldisc
Call Trace:
[..] n_tty_receive_buf2
[..] tty_ldisc_receive_buf
[..] flush_to_ldisc
[..] process_one_work
[..] worker_thread
[..] kthread
[..] ret_from_fork
tty_ldisc_reinit() should be called with ldisc_sem hold for writing,
which will protect any reader against line discipline changes.
Cc: Jiri Slaby <jslaby@suse.com>
Cc: stable@vger.kernel.org # b027e2298bd5 ("tty: fix data race between tty_init_dev and flush of buf")
Reviewed-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: syzbot+3aa9784721dfb90e984d@syzkaller.appspotmail.com
Tested-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Tested-by: Tycho Andersen <tycho@tycho.ws>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The USB-serial console implementation has never reported the actual
terminal settings used. Despite storing the corresponding cflags in its
struct console, these were never honoured on later tty open() where the
tty termios would be left initialised to the driver defaults.
Unlike the serial console implementation, the USB-serial code calls
subdriver open() already at console setup. While calling set_termios()
and write() before open() looks like it could work for some USB-serial
drivers, others definitely do not expect this, so modelling this after
serial core is going to be intrusive, if at all possible.
Instead, use a (renamed) tty helper to save the termios data used at
console setup so that the tty termios reflects the actual terminal
settings after a subsequent tty open().
Note that the calls to tty_init_termios() (tty_driver_install()) and
tty_save_termios() are serialised using the disconnect mutex.
This specifically fixes a regression that was triggered by a recent
change adding software flow control to the pl2303 driver: a getty trying
to disable flow control while leaving the baud rate unchanged would now
also set the baud rate to the driver default (prior to the flow-control
change this had been a noop).
Fixes: 7041d9c3f01b ("USB: serial: pl2303: add support for tx xon/xoff flow control")
Cc: stable <stable@vger.kernel.org> # 4.18
Cc: Florian Zumbiehl <florz@florz.de>
Reported-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Here is the big tty and serial pull request for 4.20-rc1
Lots of little things here, including a merge from the SPI tree in order
to keep things simpler for everyone to sync around for one platform.
Major stuff is:
- tty buffer clearing after use
- atmel_serial fixes and additions
- xilinx uart driver updates
and of course, lots of tiny fixes and additions to individual serial
drivers.
All of these have been in linux-next with no reported issues for a
while.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial updates from Greg KH:
"Here is the big tty and serial pull request for 4.20-rc1
Lots of little things here, including a merge from the SPI tree in
order to keep things simpler for everyone to sync around for one
platform.
Major stuff is:
- tty buffer clearing after use
- atmel_serial fixes and additions
- xilinx uart driver updates
and of course, lots of tiny fixes and additions to individual serial
drivers.
All of these have been in linux-next with no reported issues for a
while"
* tag 'tty-4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (66 commits)
of: base: Change logic in of_alias_get_alias_list()
of: base: Fix english spelling in of_alias_get_alias_list()
serial: sh-sci: do not warn if DMA transfers are not supported
serial: uartps: Do not allow use aliases >= MAX_UART_INSTANCES
tty: check name length in tty_find_polling_driver()
serial: sh-sci: Add r8a77990 support
tty: wipe buffer if not echoing data
tty: wipe buffer.
serial: fsl_lpuart: Remove the alias node dependence
TTY: sn_console: Replace spin_is_locked() with spin_trylock()
Revert "serial:serial_core: Allow use of CTS for PPS line discipline"
serial: 8250_uniphier: add auto-flow-control support
serial: 8250_uniphier: flatten probe function
serial: 8250_uniphier: remove unused "fifo-size" property
dt-bindings: serial: sh-sci: Document r8a7744 bindings
serial: uartps: Fix missing unlock on error in cdns_get_id()
tty/serial: atmel: add ISO7816 support
tty/serial_core: add ISO7816 infrastructure
serial:serial_core: Allow use of CTS for PPS line discipline
serial: docs: Fix filename for serial reference implementation
...
Pull tty ioctl updates from Al Viro:
"This is the compat_ioctl work related to tty ioctls.
Quite a bit of dead code taken out, all tty-related stuff gone from
fs/compat_ioctl.c. A bunch of compat bugs fixed - some still remain,
but all more or less generic tty-related ioctls should be covered
(remaining issues are in things like driver-private ioctls in a pcmcia
serial card driver not getting properly handled in 32bit processes on
64bit host, etc)"
* 'work.tty-ioctl' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (53 commits)
kill TIOCSERGSTRUCT
change semantics of ldisc ->compat_ioctl()
kill TIOCSER[SG]WILD
synclink_gt(): fix compat_ioctl()
pty: fix compat ioctls
compat_ioctl - kill keyboard ioctl handling
gigaset: add ->compat_ioctl()
vt_compat_ioctl(): clean up, use compat_ptr() properly
gigaset: don't try to printk userland buffer contents
dgnc: don't bother with (empty) stub for TCXONC
dgnc: leave TIOC[GS]SOFTCAR to ldisc
remove fallback to drivers for TIOCGICOUNT
dgnc: break-related ioctls won't reach ->ioctl()
kill the rest of tty COMPAT_IOCTL() entries
dgnc: TIOCM... won't reach ->ioctl()
isdn_tty: TCSBRK{,P} won't reach ->ioctl()
kill capinc_tty_ioctl()
take compat TIOC[SG]SERIAL treatment into tty_compat_ioctl()
synclink: reduce pointless checks in ->ioctl()
complete ->[sg]et_serial() switchover
...
Pull siginfo updates from Eric Biederman:
"I have been slowly sorting out siginfo and this is the culmination of
that work.
The primary result is in several ways the signal infrastructure has
been made less error prone. The code has been updated so that manually
specifying SEND_SIG_FORCED is never necessary. The conversion to the
new siginfo sending functions is now complete, which makes it
difficult to send a signal without filling in the proper siginfo
fields.
At the tail end of the patchset comes the optimization of decreasing
the size of struct siginfo in the kernel from 128 bytes to about 48
bytes on 64bit. The fundamental observation that enables this is by
definition none of the known ways to use struct siginfo uses the extra
bytes.
This comes at the cost of a small user space observable difference.
For the rare case of siginfo being injected into the kernel only what
can be copied into kernel_siginfo is delivered to the destination, the
rest of the bytes are set to 0. For cases where the signal and the
si_code are known this is safe, because we know those bytes are not
used. For cases where the signal and si_code combination is unknown
the bits that won't fit into struct kernel_siginfo are tested to
verify they are zero, and the send fails if they are not.
I made an extensive search through userspace code and I could not find
anything that would break because of the above change. If it turns out
I did break something it will take just the revert of a single change
to restore kernel_siginfo to the same size as userspace siginfo.
Testing did reveal dependencies on preferring the signo passed to
sigqueueinfo over si->signo, so bit the bullet and added the
complexity necessary to handle that case.
Testing also revealed bad things can happen if a negative signal
number is passed into the system calls. Something no sane application
will do but something a malicious program or a fuzzer might do. So I
have fixed the code that performs the bounds checks to ensure negative
signal numbers are handled"
* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (80 commits)
signal: Guard against negative signal numbers in copy_siginfo_from_user32
signal: Guard against negative signal numbers in copy_siginfo_from_user
signal: In sigqueueinfo prefer sig not si_signo
signal: Use a smaller struct siginfo in the kernel
signal: Distinguish between kernel_siginfo and siginfo
signal: Introduce copy_siginfo_from_user and use it's return value
signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE
signal: Fail sigqueueinfo if si_signo != sig
signal/sparc: Move EMT_TAGOVF into the generic siginfo.h
signal/unicore32: Use force_sig_fault where appropriate
signal/unicore32: Generate siginfo in ucs32_notify_die
signal/unicore32: Use send_sig_fault where appropriate
signal/arc: Use force_sig_fault where appropriate
signal/arc: Push siginfo generation into unhandled_exception
signal/ia64: Use force_sig_fault where appropriate
signal/ia64: Use the force_sig(SIGSEGV,...) in ia64_rt_sigreturn
signal/ia64: Use the generic force_sigsegv in setup_frame
signal/arm/kvm: Use send_sig_mceerr
signal/arm: Use send_sig_fault where appropriate
signal/arm: Use force_sig_fault where appropriate
...
First of all, make it return int. Returning long when native method
had never allowed that is ridiculous and inconvenient.
More importantly, change the caller; if ldisc ->compat_ioctl() is NULL
or returns -ENOIOCTLCMD, tty_compat_ioctl() will try to feed cmd and
compat_ptr(arg) to ldisc's native ->ioctl().
That simplifies ->compat_ioctl() instances quite a bit - they only
need to deal with ioctls that are neither generic tty ones (those
would get shunted off to tty_ioctl()) nor simple compat pointer ones.
Note that something like TCFLSH won't reach ->compat_ioctl(),
even if ldisc ->ioctl() does handle it - it will be recognized
earlier and passed to tty_ioctl() (and ultimately - ldisc ->ioctl()).
For many ldiscs it means that NULL ->compat_ioctl() does the
right thing. Those where it won't serve (see e.g. n_r3964.c) are
also easily dealt with - we need to handle the numeric-argument
ioctls (calling the native instance) and, if such would exist,
the ioctls that need layout conversion, etc.
All in-tree ldiscs dealt with.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Replace send_sig and force_sig in __do_SAK with group_send_sig_info
the general helper for sending a signal to a process group. This is
wordier but it allows specifying PIDTYPE_SID so that the signal code
knows the signal went to a session.
Both force_sig() and send_sig(..., 1) specify SEND_SIG_PRIV and the
new call of group_send_sig_info does that explicitly. This is enough
to ensure even a pid namespace init is killed.
The global init remains unkillable. The guarantee that __do_SAK tries
to provide is a clean path to login to a machine. As the global init is
unkillable, if it chooses to hold open a tty it can violate this
guarantee. A technique other than killing processes would be needed
to provide this guarantee to userspace.
The only difference between force_sig and send_sig when sending
SIGKILL is that SIGNAL_UNKILLABLE is cleared. This has no affect on
the processing of a signal sent with SEND_SIG_PRIV by any process, making
it unnecessary, and not behavior that needs to be preserved.
force_sig was used originally because it did not take as many locks as
send_sig. Today send_sig, force_sig and group_send_sig_info take the
same locks when delivering a signal.
group_send_sig_info also contains a permission check that force_sig
and send_sig do not. However the presence of SEND_SIG_PRIV makes the
permission check a noop. So the permission check does not result
in any behavioral differences.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
That code had been live for 11 weeks back in 1992, but it had been 26 years
since sys_ioctl() began handling FIONBIO on its own. Time to to bury the body,
already...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
