diff options
| -rw-r--r-- | kernels/linux-libre-lts-knock/0001-n_tty-Fix-n_tty_write-crash-when-echoing-in-raw-mode.patch | 83 | ||||
| -rw-r--r-- | kernels/linux-libre-lts-knock/PKGBUILD | 10 |
2 files changed, 90 insertions, 3 deletions
diff --git a/kernels/linux-libre-lts-knock/0001-n_tty-Fix-n_tty_write-crash-when-echoing-in-raw-mode.patch b/kernels/linux-libre-lts-knock/0001-n_tty-Fix-n_tty_write-crash-when-echoing-in-raw-mode.patch new file mode 100644 index 000000000..cb659dc7d --- /dev/null +++ b/kernels/linux-libre-lts-knock/0001-n_tty-Fix-n_tty_write-crash-when-echoing-in-raw-mode.patch @@ -0,0 +1,83 @@ +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: [PATCH] n_tty: Fix n_tty_write crash when echoing in raw mode + +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> +Cc: <stable@vger.kernel.org> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + drivers/tty/n_tty.c | 4 ++++ + 1 file changed, 4 insertions(+) + +diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c +index 41fe8a0..fe9d129 100644 +--- a/drivers/tty/n_tty.c ++++ b/drivers/tty/n_tty.c +@@ -2353,8 +2353,12 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, + 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; +-- +1.9.2 + diff --git a/kernels/linux-libre-lts-knock/PKGBUILD b/kernels/linux-libre-lts-knock/PKGBUILD index 221f808eb..dab0fd29f 100644 --- a/kernels/linux-libre-lts-knock/PKGBUILD +++ b/kernels/linux-libre-lts-knock/PKGBUILD @@ -1,4 +1,4 @@ -# $Id: PKGBUILD 212087 2014-05-06 15:55:48Z bpiotrowski $ +# $Id: PKGBUILD 212332 2014-05-13 08:23:48Z bpiotrowski $ # Maintainer: Tobias Powalowski <tpowa@archlinux.org> # Maintainer: Thomas Baechler <thomas@archlinux.org> # Maintainer (Parabola): André Silva <emulatorman@parabola.nu> @@ -13,8 +13,8 @@ _basekernel=3.10 _sublevel=39 _knockpatchver=${_basekernel} pkgver=${_basekernel}.${_sublevel} -pkgrel=1 -_lxopkgver=${_basekernel}.38 # nearly always the same as pkgver +pkgrel=2 +_lxopkgver=${_basekernel}.39 # nearly always the same as pkgver arch=('i686' 'x86_64' 'mips64el') url="https://gnunet.org/knock" license=('GPL2') @@ -32,6 +32,7 @@ source=("http://linux-libre.fsfla.org/pub/linux-libre/releases/${_basekernel}-gn 'boot-logo.patch' 'change-default-console-loglevel.patch' 'criu-no-expert.patch' + '0001-n_tty-Fix-n_tty_write-crash-when-echoing-in-raw-mode.patch' "http://www.linux-libre.fsfla.org/pub/linux-libre/lemote/gnewsense/pool/debuginfo/linux-patches-${_lxopkgver}-gnu_0loongsonlibre_mipsel.tar.xz") md5sums=('d562fd52580a3b6b18b6eeb5921d1d5c' '0663686c1e5495b999a175aa7809ea92' @@ -79,6 +80,9 @@ prepare() { # patch from fedora patch -Np1 -i "${srcdir}/criu-no-expert.patch" + # CVE-2014-0196 + patch -Np1 -i "${srcdir}/0001-n_tty-Fix-n_tty_write-crash-when-echoing-in-raw-mode.patch" + if [ "$CARCH" == "mips64el" ]; then sed -i "s|^EXTRAVERSION.*|EXTRAVERSION =-libre-lts-knock|" Makefile sed -r "s|^( SUBLEVEL = ).*|\1$_sublevel|" \ |