--- /dev/null
+From 501fed45b7e8836ee9373f4d31e2d85e3db6103a Mon Sep 17 00:00:00 2001
+From: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
+Date: Fri, 2 May 2014 18:58:24 -0400
+Subject: drivers/tty/hvc: don't free hvc_console_setup after init
+
+From: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
+
+commit 501fed45b7e8836ee9373f4d31e2d85e3db6103a upstream.
+
+When 'console=hvc0' is specified to the kernel parameter in x86 KVM guest,
+hvc console is setup within a kthread. However, that will cause SEGV
+and the boot will fail when the driver is builtin to the kernel,
+because currently hvc_console_setup() is annotated with '__init'. This
+patch removes '__init' to boot the guest successfully with 'console=hvc0'.
+
+Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/tty/hvc/hvc_console.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/drivers/tty/hvc/hvc_console.c
++++ b/drivers/tty/hvc/hvc_console.c
+@@ -190,7 +190,7 @@ static struct tty_driver *hvc_console_de
+ return hvc_driver;
+ }
+
+-static int __init hvc_console_setup(struct console *co, char *options)
++static int hvc_console_setup(struct console *co, char *options)
+ {
+ if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES)
+ return -ENODEV;
--- /dev/null
+From 4291086b1f081b869c6d79e5b7441633dc3ace00 Mon Sep 17 00:00:00 2001
+From: Peter Hurley <peter@hurleysoftware.com>
+Date: Sat, 3 May 2014 14:04:59 +0200
+Subject: n_tty: Fix n_tty_write crash when echoing in raw mode
+
+From: Peter Hurley <peter@hurleysoftware.com>
+
+commit 4291086b1f081b869c6d79e5b7441633dc3ace00 upstream.
+
+The tty atomic_write_lock does not provide an exclusion guarantee for
+the tty driver if the termios settings are LECHO & !OPOST. And since
+it is unexpected and not allowed to call TTY buffer helpers like
+tty_insert_flip_string concurrently, this may lead to crashes when
+concurrect writers call pty_write. In that case the following two
+writers:
+* the ECHOing from a workqueue and
+* pty_write from the process
+race and can overflow the corresponding TTY buffer like follows.
+
+If we look into tty_insert_flip_string_fixed_flag, there is:
+ int space = __tty_buffer_request_room(port, goal, flags);
+ struct tty_buffer *tb = port->buf.tail;
+ ...
+ memcpy(char_buf_ptr(tb, tb->used), chars, space);
+ ...
+ tb->used += space;
+
+so the race of the two can result in something like this:
+ A B
+__tty_buffer_request_room
+ __tty_buffer_request_room
+memcpy(buf(tb->used), ...)
+tb->used += space;
+ memcpy(buf(tb->used), ...) ->BOOM
+
+B's memcpy is past the tty_buffer due to the previous A's tb->used
+increment.
+
+Since the N_TTY line discipline input processing can output
+concurrently with a tty write, obtain the N_TTY ldisc output_lock to
+serialize echo output with normal tty writes. This ensures the tty
+buffer helper tty_insert_flip_string is not called concurrently and
+everything is fine.
+
+Note that this is nicely reproducible by an ordinary user using
+forkpty and some setup around that (raw termios + ECHO). And it is
+present in kernels at least after commit
+d945cb9cce20ac7143c2de8d88b187f62db99bdc (pty: Rework the pty layer to
+use the normal buffering logic) in 2.6.31-rc3.
+
+js: add more info to the commit log
+js: switch to bool
+js: lock unconditionally
+js: lock only the tty->ops->write call
+
+References: CVE-2014-0196
+Reported-and-tested-by: Jiri Slaby <jslaby@suse.cz>
+Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
+Signed-off-by: Jiri Slaby <jslaby@suse.cz>
+Cc: Linus Torvalds <torvalds@linux-foundation.org>
+Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/tty/n_tty.c | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+--- a/drivers/tty/n_tty.c
++++ b/drivers/tty/n_tty.c
+@@ -2356,8 +2356,12 @@ static ssize_t n_tty_write(struct tty_st
+ if (tty->ops->flush_chars)
+ tty->ops->flush_chars(tty);
+ } else {
++ struct n_tty_data *ldata = tty->disc_data;
++
+ while (nr > 0) {
++ mutex_lock(&ldata->output_lock);
+ c = tty->ops->write(tty, b, nr);
++ mutex_unlock(&ldata->output_lock);
+ if (c < 0) {
+ retval = c;
+ goto break_out;
--- /dev/null
+From 62a0d8d7c2b29f92850e4ee3c38e5dfd936e92b2 Mon Sep 17 00:00:00 2001
+From: Peter Hurley <peter@hurleysoftware.com>
+Date: Fri, 2 May 2014 10:56:12 -0400
+Subject: tty: Fix lockless tty buffer race
+
+From: Peter Hurley <peter@hurleysoftware.com>
+
+commit 62a0d8d7c2b29f92850e4ee3c38e5dfd936e92b2 upstream.
+
+Commit 6a20dbd6caa2358716136144bf524331d70b1e03,
+"tty: Fix race condition between __tty_buffer_request_room and flush_to_ldisc"
+correctly identifies an unsafe race condition between
+__tty_buffer_request_room() and flush_to_ldisc(), where the consumer
+flush_to_ldisc() prematurely advances the head before consuming the
+last of the data committed. For example:
+
+ CPU 0 | CPU 1
+__tty_buffer_request_room | flush_to_ldisc
+ ... | ...
+ | count = head->commit - head->read
+ n = tty_buffer_alloc() |
+ b->commit = b->used |
+ b->next = n |
+ | if (!count) /* T */
+ | if (head->next == NULL) /* F */
+ | buf->head = head->next
+
+In this case, buf->head has been advanced but head->commit may have
+been updated with a new value.
+
+Instead of reintroducing an unnecessary lock, fix the race locklessly.
+Read the commit-next pair in the reverse order of writing, which guarantees
+the commit value read is the latest value written if the head is
+advancing.
+
+Reported-by: Manfred Schlaegl <manfred.schlaegl@gmx.at>
+Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/tty/tty_buffer.c | 17 ++++++++++++++---
+ 1 file changed, 14 insertions(+), 3 deletions(-)
+
+--- a/drivers/tty/tty_buffer.c
++++ b/drivers/tty/tty_buffer.c
+@@ -258,7 +258,11 @@ static int __tty_buffer_request_room(str
+ n->flags = flags;
+ buf->tail = n;
+ b->commit = b->used;
+- smp_mb();
++ /* paired w/ barrier in flush_to_ldisc(); ensures the
++ * latest commit value can be read before the head is
++ * advanced to the next buffer
++ */
++ smp_wmb();
+ b->next = n;
+ } else if (change)
+ size = 0;
+@@ -444,17 +448,24 @@ static void flush_to_ldisc(struct work_s
+
+ while (1) {
+ struct tty_buffer *head = buf->head;
++ struct tty_buffer *next;
+ int count;
+
+ /* Ldisc or user is trying to gain exclusive access */
+ if (atomic_read(&buf->priority))
+ break;
+
++ next = head->next;
++ /* paired w/ barrier in __tty_buffer_request_room();
++ * ensures commit value read is not stale if the head
++ * is advancing to the next buffer
++ */
++ smp_rmb();
+ count = head->commit - head->read;
+ if (!count) {
+- if (head->next == NULL)
++ if (next == NULL)
+ break;
+- buf->head = head->next;
++ buf->head = next;
+ tty_buffer_free(port, head);
+ continue;
+ }
--- /dev/null
+From b790f210fe8423eff881b2a8a93ba5dbc45534d0 Mon Sep 17 00:00:00 2001
+From: Michael Welling <mwelling@ieee.org>
+Date: Fri, 25 Apr 2014 19:27:48 -0500
+Subject: tty: serial: 8250_core.c Bug fix for Exar chips.
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+From: Michael Welling <mwelling@ieee.org>
+
+commit b790f210fe8423eff881b2a8a93ba5dbc45534d0 upstream.
+
+The sleep function was updated to put the serial port to sleep only when necessary.
+This appears to resolve the errant behavior of the driver as described in
+Kernel Bug 61961 – "My Exar Corp. XR17C/D152 Dual PCI UART modem does not
+work with 3.8.0".
+
+Signed-off-by: Michael Welling <mwelling@ieee.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/tty/serial/8250/8250_core.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/drivers/tty/serial/8250/8250_core.c
++++ b/drivers/tty/serial/8250/8250_core.c
+@@ -555,7 +555,7 @@ static void serial8250_set_sleep(struct
+ */
+ if ((p->port.type == PORT_XR17V35X) ||
+ (p->port.type == PORT_XR17D15X)) {
+- serial_out(p, UART_EXAR_SLEEP, 0xff);
++ serial_out(p, UART_EXAR_SLEEP, sleep ? 0xff : 0);
+ return;
+ }
+
projects / thirdparty / kernel / stable-queue.git / commitdiff
