From 0dbc7d243ce4a002c3b25e444753e386b0d8da28 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Tue, 13 May 2014 08:30:20 -0300 Subject: linux-libre-lts-3.10.39-2: fix CVE-2014-0196 --- ..._tty_write-crash-when-echoing-in-raw-mode.patch | 83 ++++++++++++++++++++++ libre/linux-libre-lts/PKGBUILD | 13 ++-- 2 files changed, 92 insertions(+), 4 deletions(-) create mode 100644 libre/linux-libre-lts/0001-n_tty-Fix-n_tty_write-crash-when-echoing-in-raw-mode.patch diff --git a/libre/linux-libre-lts/0001-n_tty-Fix-n_tty_write-crash-when-echoing-in-raw-mode.patch b/libre/linux-libre-lts/0001-n_tty-Fix-n_tty_write-crash-when-echoing-in-raw-mode.patch new file mode 100644 index 000000000..cb659dc7d --- /dev/null +++ b/libre/linux-libre-lts/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 +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 +Signed-off-by: Peter Hurley +Signed-off-by: Jiri Slaby +Cc: Linus Torvalds +Cc: Alan Cox +Cc: +Signed-off-by: Greg Kroah-Hartman +--- + 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/libre/linux-libre-lts/PKGBUILD b/libre/linux-libre-lts/PKGBUILD index dc9477d16..44978f9ba 100644 --- a/libre/linux-libre-lts/PKGBUILD +++ b/libre/linux-libre-lts/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 # Maintainer: Thomas Baechler # Maintainer (Parabola): André Silva @@ -12,8 +12,8 @@ pkgbase=linux-libre-lts # Build stock -LIBRE-LTS kernel _basekernel=3.10 _sublevel=39 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="http://linux-libre.fsfla.org/" license=('GPL2') @@ -30,6 +30,7 @@ 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' @@ -41,7 +42,8 @@ md5sums=('d562fd52580a3b6b18b6eeb5921d1d5c' '04b21c79df0a952c22d681dd4f4562df' 'f3def2cefdcbb954c21d8505d23cc83c' 'd50c1ac47394e9aec637002ef3392bd1' - 'e5ae030129ed128c61fe29b926476a19') + 'da00b78faadbe939943b32305e4c68f8' + '64e128839d1e32bd0789cf1b3fc3d64b') if [ "$CARCH" != "mips64el" ]; then # don't use the Loongson-specific patches on non-mips64el arches. unset source[${#source[@]}-1] @@ -73,6 +75,9 @@ 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 [ "$CARCH" == "mips64el" ]; then sed -i "s|^EXTRAVERSION.*|EXTRAVERSION =-libre-lts|" Makefile sed -r "s|^( SUBLEVEL = ).*|\1$_sublevel|" \ -- cgit v1.2.3-54-g00ecf