From 12d5edf442c044096a53992a5be2dce56d31ffd7 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 7 Dec 2016 14:52:06 -0300 Subject: linux-libre-lts-4.4.36_gnu-1: updating version --- .../fix_race_condition_in_packet_set_ring.diff | 84 ++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 libre/linux-libre-lts/fix_race_condition_in_packet_set_ring.diff (limited to 'libre/linux-libre-lts/fix_race_condition_in_packet_set_ring.diff') diff --git a/libre/linux-libre-lts/fix_race_condition_in_packet_set_ring.diff b/libre/linux-libre-lts/fix_race_condition_in_packet_set_ring.diff new file mode 100644 index 000000000..12048f611 --- /dev/null +++ b/libre/linux-libre-lts/fix_race_condition_in_packet_set_ring.diff @@ -0,0 +1,84 @@ +From: Philip Pettersson + +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 +Signed-off-by: Eric Dumazet +--- + 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; + } -- cgit v1.2.3