CVE-2016-8655

This commit is contained in:
Andreas Radke 2016-12-06 12:09:59 +00:00
parent 066bf7087a
commit cef8e147af
2 changed files with 93 additions and 3 deletions

View File

@ -6,9 +6,9 @@ pkgbase=linux # Build stock -ARCH kernel
#pkgbase=linux-custom # Build kernel with a different name
_srcname=linux-4.8
pkgver=4.8.12
pkgrel=1
pkgrel=2
arch=('i686' 'x86_64')
url="http://www.kernel.org/"
url="https://www.kernel.org/"
license=('GPL2')
makedepends=('xmlto' 'docbook-xsl' 'kmod' 'inetutils' 'bc' 'libelf')
options=('!strip')
@ -23,6 +23,7 @@ source=("https://www.kernel.org/pub/linux/kernel/v4.x/${_srcname}.tar.xz"
# standard config files for mkinitcpio ramdisk
'linux.preset'
'change-default-console-loglevel.patch'
fix_race_condition_in_packet_set_ring.diff
)
sha256sums=('3e9150065f193d3d94bcf46a1fe9f033c7ef7122ab71d75a7fb5a2f0c9a7e11a'
@ -33,7 +34,8 @@ sha256sums=('3e9150065f193d3d94bcf46a1fe9f033c7ef7122ab71d75a7fb5a2f0c9a7e11a'
'41b9a64542befd2fea170776e8ec22a7d158dd3273633afc9b91662c448cd90a'
'834bd254b56ab71d73f59b3221f056c72f559553c04718e350ab2a3e2991afe0'
'ad6344badc91ad0630caacde83f7f9b97276f80d26a20619a87952be65492c65'
'1256b241cd477b265a3c2d64bdc19ffe3c9bbcee82ea3994c590c2c76e767d99')
'1256b241cd477b265a3c2d64bdc19ffe3c9bbcee82ea3994c590c2c76e767d99'
'ad1ee95f906f88d31fcdb9273cd08e02e8eda177449f0c98dc1bff8cbf1483c2')
validpgpkeys=(
'ABAF11C65A2970B130ABE3C479BE3E4300411886' # Linus Torvalds
'647F28654894E3BD457199BE38DBBDC86092693E' # Greg Kroah-Hartman
@ -47,6 +49,10 @@ prepare() {
# add upstream patch
patch -p1 -i "${srcdir}/patch-${pkgver}"
# fix a race condition that allows to gain root
# https://marc.info/?l=linux-netdev&m=148054660230570&w=2
patch -p1 -i "${srcdir}/fix_race_condition_in_packet_set_ring.diff"
# add latest fixes from stable queue, if needed
# http://git.kernel.org/?p=linux/kernel/git/stable/stable-queue.git

View File

@ -0,0 +1,84 @@
From: Philip Pettersson <philip.pettersson@gmail.com>
When packet_set_ring creates a ring buffer it will initialize a
struct timer_list if the packet version is TPACKET_V3. This value
can then be raced by a different thread calling setsockopt to
set the version to TPACKET_V1 before packet_set_ring has finished.
This leads to a use-after-free on a function pointer in the
struct timer_list when the socket is closed as the previously
initialized timer will not be deleted.
The bug is fixed by taking lock_sock(sk) in packet_setsockopt when
changing the packet version while also taking the lock at the start
of packet_set_ring.
Fixes: f6fb8f100b80 ("af-packet: TPACKET_V3 flexible buffer implementation.")
Signed-off-by: Philip Pettersson <philip.pettersson@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/packet/af_packet.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index d2238b204691b8e4f2e3acb9bc167b553ba32d50..dd2332390c45bbff7c3fc5d259453f2e1ca352bf 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -3648,19 +3648,25 @@ packet_setsockopt(struct socket *sock, int level, int optname, char __user *optv
if (optlen != sizeof(val))
return -EINVAL;
- if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
- return -EBUSY;
if (copy_from_user(&val, optval, sizeof(val)))
return -EFAULT;
switch (val) {
case TPACKET_V1:
case TPACKET_V2:
case TPACKET_V3:
- po->tp_version = val;
- return 0;
+ break;
default:
return -EINVAL;
}
+ lock_sock(sk);
+ if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) {
+ ret = -EBUSY;
+ } else {
+ po->tp_version = val;
+ ret = 0;
+ }
+ release_sock(sk);
+ return ret;
}
case PACKET_RESERVE:
{
@@ -4164,6 +4170,7 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
/* Added to avoid minimal code churn */
struct tpacket_req *req = &req_u->req;
+ lock_sock(sk);
/* Opening a Tx-ring is NOT supported in TPACKET_V3 */
if (!closing && tx_ring && (po->tp_version > TPACKET_V2)) {
net_warn_ratelimited("Tx-ring is not supported.\n");
@@ -4245,7 +4252,6 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
goto out;
}
- lock_sock(sk);
/* Detach socket from network */
spin_lock(&po->bind_lock);
@@ -4294,11 +4300,11 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
if (!tx_ring)
prb_shutdown_retire_blk_timer(po, rb_queue);
}
- release_sock(sk);
if (pg_vec)
free_pg_vec(pg_vec, order, req->tp_block_nr);
out:
+ release_sock(sk);
return err;
}