Update to v4.4.36

2 files changed, 93 insertions, 3 deletions

diff --git a/PKGBUILD b/PKGBUILD
index 10ac2e3d4795..690b60a5c9bc 100644
--- a/PKGBUILD
+++ b/PKGBUILD
@@ -4,7 +4,7 @@
 #pkgbase=linux-lts
 pkgbase=linux-lts-surface4
 _srcname=linux-4.4
-pkgver=4.4.34
+pkgver=4.4.36
 pkgrel=1
 arch=('i686' 'x86_64')
 url="http://www.kernel.org/"
@@ -18,19 +18,21 @@ source=(https://www.kernel.org/pub/linux/kernel/v4.x/${_srcname}.tar.{xz,sign}
         # standard config files for mkinitcpio ramdisk
         linux-lts.preset
         change-default-console-loglevel.patch
+        fix_race_condition_in_packet_set_ring.diff
         0001-sdhci-revert.patch
-		0002-surface-wifi.patch
+        0002-surface-wifi.patch
         0003-surface-cover.patch
         0004-surface-pro4-button.patch)
 # https://www.kernel.org/pub/linux/kernel/v4.x/sha256sums.asc
 sha256sums=('401d7c8fef594999a460d10c72c5a94e9c2e1022f16795ec51746b0d165418b2'
             'SKIP'
-            'b1e77807267aa3ec81e46c15b1a4be0c7169b6c19eb52cd371c4f58dd2183a9d'
+            '468ddfe3f29c314b40e32410c796fda9277620d50bc47b50fafc8a5a4c375e61'
             'SKIP'
             'e8d200b125b4391020c2bc1f43bf8f3a372f0bbdaf9bad71b31574edab7f908f'
             '236fc805c543cb774785f630bf37c7fdc2ff7c9904bb240ff70e0b7213058de5'
             '9e9e7ee3476e55e68390eda7e983fa18d44e76db5521f023fd2b388b1150bc40'
             '1256b241cd477b265a3c2d64bdc19ffe3c9bbcee82ea3994c590c2c76e767d99'
+            'ad1ee95f906f88d31fcdb9273cd08e02e8eda177449f0c98dc1bff8cbf1483c2'
             '5313df7cb5b4d005422bd4cd0dae956b2dadba8f3db904275aaf99ac53894375'
             'c59a18d38d75fec7e9cc3b4efb6a997b3714c3156f6f80a6915bd16db409cde9'
             '26ed3893c370952f8310a0b2bdecdabf5e3185ad8e9100f1e2ef5260fdf52c84'
@@ -46,6 +48,10 @@ prepare() {
   # add upstream patch
   patch -p1 -i "${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
 
diff --git a/fix_race_condition_in_packet_set_ring.diff b/fix_race_condition_in_packet_set_ring.diff
new file mode 100644
index 000000000000..12048f611d1a
--- /dev/null
+++ b/fix_race_condition_in_packet_set_ring.diff
@@ -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;
+ }