CVE-2016-8655 fix race condition in packet_set_ring (rhbz 1400019 1401820)
This commit is contained in:
parent
b2248a2796
commit
d96d33b424
|
@ -0,0 +1,92 @@
|
|||
From 84ac7260236a49c79eede91617700174c2c19b0c Mon Sep 17 00:00:00 2001
|
||||
From: Philip Pettersson <philip.pettersson@gmail.com>
|
||||
Date: Wed, 30 Nov 2016 14:55:36 -0800
|
||||
Subject: [PATCH] packet: fix race condition in packet_set_ring
|
||||
|
||||
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>
|
||||
Signed-off-by: David S. Miller <davem@davemloft.net>
|
||||
---
|
||||
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 d2238b2..dd23323 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;
|
||||
}
|
||||
|
||||
--
|
||||
2.9.3
|
||||
|
Loading…
Reference in New Issue