mirror of
https://github.com/Divested-Mobile/DivestOS-Build.git
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93 lines
2.8 KiB
Diff
93 lines
2.8 KiB
Diff
From 84ac7260236a49c79eede91617700174c2c19b0c Mon Sep 17 00:00:00 2001
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From: Philip Pettersson <philip.pettersson@gmail.com>
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Date: Wed, 30 Nov 2016 14:55:36 -0800
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Subject: packet: fix race condition in packet_set_ring
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When packet_set_ring creates a ring buffer it will initialize a
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struct timer_list if the packet version is TPACKET_V3. This value
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can then be raced by a different thread calling setsockopt to
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set the version to TPACKET_V1 before packet_set_ring has finished.
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This leads to a use-after-free on a function pointer in the
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struct timer_list when the socket is closed as the previously
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initialized timer will not be deleted.
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The bug is fixed by taking lock_sock(sk) in packet_setsockopt when
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changing the packet version while also taking the lock at the start
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of packet_set_ring.
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Fixes: f6fb8f100b80 ("af-packet: TPACKET_V3 flexible buffer implementation.")
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Signed-off-by: Philip Pettersson <philip.pettersson@gmail.com>
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Signed-off-by: Eric Dumazet <edumazet@google.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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---
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net/packet/af_packet.c | 18 ++++++++++++------
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1 file changed, 12 insertions(+), 6 deletions(-)
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diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
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index d2238b2..dd23323 100644
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--- a/net/packet/af_packet.c
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+++ b/net/packet/af_packet.c
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@@ -3648,19 +3648,25 @@ packet_setsockopt(struct socket *sock, int level, int optname, char __user *optv
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if (optlen != sizeof(val))
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return -EINVAL;
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- if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
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- return -EBUSY;
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if (copy_from_user(&val, optval, sizeof(val)))
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return -EFAULT;
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switch (val) {
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case TPACKET_V1:
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case TPACKET_V2:
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case TPACKET_V3:
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- po->tp_version = val;
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- return 0;
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+ break;
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default:
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return -EINVAL;
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}
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+ lock_sock(sk);
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+ if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) {
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+ ret = -EBUSY;
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+ } else {
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+ po->tp_version = val;
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+ ret = 0;
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+ }
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+ release_sock(sk);
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+ return ret;
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}
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case PACKET_RESERVE:
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{
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@@ -4164,6 +4170,7 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
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/* Added to avoid minimal code churn */
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struct tpacket_req *req = &req_u->req;
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+ lock_sock(sk);
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/* Opening a Tx-ring is NOT supported in TPACKET_V3 */
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if (!closing && tx_ring && (po->tp_version > TPACKET_V2)) {
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net_warn_ratelimited("Tx-ring is not supported.\n");
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@@ -4245,7 +4252,6 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
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goto out;
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}
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- lock_sock(sk);
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/* Detach socket from network */
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spin_lock(&po->bind_lock);
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@@ -4294,11 +4300,11 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
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if (!tx_ring)
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prb_shutdown_retire_blk_timer(po, rb_queue);
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}
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- release_sock(sk);
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if (pg_vec)
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free_pg_vec(pg_vec, order, req->tp_block_nr);
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out:
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+ release_sock(sk);
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return err;
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}
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--
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cgit v1.1
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