linux-stable.git/net/core, branch v5.4.90

net: drop bogus skb with CHECKSUM_PARTIAL and offset beyond end of trimmed packet

2021-01-17T13:05:38+00:00

commit 54970a2fbb673f090b7f02d7f57b10b2e0707155 upstream.

syzbot reproduces BUG_ON in skb_checksum_help():
tun creates (bogus) skb with huge partial-checksummed area and
small ip packet inside. Then ip_rcv trims the skb based on size
of internal ip packet, after that csum offset points beyond of
trimmed skb. Then checksum_tg() called via netfilter hook
triggers BUG_ON:

        offset = skb_checksum_start_offset(skb);
        BUG_ON(offset >= skb_headlen(skb));

To work around the problem this patch forces pskb_trim_rcsum_slow()
to return -EINVAL in described scenario. It allows its callers to
drop such kind of packets.

Link: https://syzkaller.appspot.com/bug?id=b419a5ca95062664fe1a60b764621eb4526e2cd0
Reported-by: syzbot+7010af67ced6105e5ab6@syzkaller.appspotmail.com
Signed-off-by: Vasily Averin 
Acked-by: Willem de Bruijn 
Link: https://lore.kernel.org/r/1b2494af-2c56-8ee2-7bc0-923fcad1cdf8@virtuozzo.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net-sysfs: take the rtnl lock when accessing xps_rxqs_map and num_tc

2021-01-12T19:16:13+00:00

[ Upstream commit 4ae2bb81649dc03dfc95875f02126b14b773f7ab ]

Accesses to dev->xps_rxqs_map (when using dev->num_tc) should be
protected by the rtnl lock, like we do for netif_set_xps_queue. I didn't
see an actual bug being triggered, but let's be safe here and take the
rtnl lock while accessing the map in sysfs.

Fixes: 8af2c06ff4b1 ("net-sysfs: Add interface for Rx queue(s) map per Tx queue")
Signed-off-by: Antoine Tenart 
Reviewed-by: Alexander Duyck 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net-sysfs: take the rtnl lock when storing xps_rxqs

2021-01-12T19:16:13+00:00

[ Upstream commit 2d57b4f142e0b03e854612b8e28978935414bced ]

Two race conditions can be triggered when storing xps rxqs, resulting in
various oops and invalid memory accesses:

1. Calling netdev_set_num_tc while netif_set_xps_queue:

   - netif_set_xps_queue uses dev->tc_num as one of the parameters to
     compute the size of new_dev_maps when allocating it. dev->tc_num is
     also used to access the map, and the compiler may generate code to
     retrieve this field multiple times in the function.

   - netdev_set_num_tc sets dev->tc_num.

   If new_dev_maps is allocated using dev->tc_num and then dev->tc_num
   is set to a higher value through netdev_set_num_tc, later accesses to
   new_dev_maps in netif_set_xps_queue could lead to accessing memory
   outside of new_dev_maps; triggering an oops.

2. Calling netif_set_xps_queue while netdev_set_num_tc is running:

   2.1. netdev_set_num_tc starts by resetting the xps queues,
        dev->tc_num isn't updated yet.

   2.2. netif_set_xps_queue is called, setting up the map with the
        *old* dev->num_tc.

   2.3. netdev_set_num_tc updates dev->tc_num.

   2.4. Later accesses to the map lead to out of bound accesses and
        oops.

   A similar issue can be found with netdev_reset_tc.

One way of triggering this is to set an iface up (for which the driver
uses netdev_set_num_tc in the open path, such as bnx2x) and writing to
xps_rxqs in a concurrent thread. With the right timing an oops is
triggered.

Both issues have the same fix: netif_set_xps_queue, netdev_set_num_tc
and netdev_reset_tc should be mutually exclusive. We do that by taking
the rtnl lock in xps_rxqs_store.

Fixes: 8af2c06ff4b1 ("net-sysfs: Add interface for Rx queue(s) map per Tx queue")
Signed-off-by: Antoine Tenart 
Reviewed-by: Alexander Duyck 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net-sysfs: take the rtnl lock when accessing xps_cpus_map and num_tc

2021-01-12T19:16:13+00:00

[ Upstream commit fb25038586d0064123e393cadf1fadd70a9df97a ]

Accesses to dev->xps_cpus_map (when using dev->num_tc) should be
protected by the rtnl lock, like we do for netif_set_xps_queue. I didn't
see an actual bug being triggered, but let's be safe here and take the
rtnl lock while accessing the map in sysfs.

Fixes: 184c449f91fe ("net: Add support for XPS with QoS via traffic classes")
Signed-off-by: Antoine Tenart 
Reviewed-by: Alexander Duyck 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net-sysfs: take the rtnl lock when storing xps_cpus

2021-01-12T19:16:13+00:00

[ Upstream commit 1ad58225dba3f2f598d2c6daed4323f24547168f ]

Two race conditions can be triggered when storing xps cpus, resulting in
various oops and invalid memory accesses:

1. Calling netdev_set_num_tc while netif_set_xps_queue:

   - netif_set_xps_queue uses dev->tc_num as one of the parameters to
     compute the size of new_dev_maps when allocating it. dev->tc_num is
     also used to access the map, and the compiler may generate code to
     retrieve this field multiple times in the function.

   - netdev_set_num_tc sets dev->tc_num.

   If new_dev_maps is allocated using dev->tc_num and then dev->tc_num
   is set to a higher value through netdev_set_num_tc, later accesses to
   new_dev_maps in netif_set_xps_queue could lead to accessing memory
   outside of new_dev_maps; triggering an oops.

2. Calling netif_set_xps_queue while netdev_set_num_tc is running:

   2.1. netdev_set_num_tc starts by resetting the xps queues,
        dev->tc_num isn't updated yet.

   2.2. netif_set_xps_queue is called, setting up the map with the
        *old* dev->num_tc.

   2.3. netdev_set_num_tc updates dev->tc_num.

   2.4. Later accesses to the map lead to out of bound accesses and
        oops.

   A similar issue can be found with netdev_reset_tc.

One way of triggering this is to set an iface up (for which the driver
uses netdev_set_num_tc in the open path, such as bnx2x) and writing to
xps_cpus in a concurrent thread. With the right timing an oops is
triggered.

Both issues have the same fix: netif_set_xps_queue, netdev_set_num_tc
and netdev_reset_tc should be mutually exclusive. We do that by taking
the rtnl lock in xps_cpus_store.

Fixes: 184c449f91fe ("net: Add support for XPS with QoS via traffic classes")
Signed-off-by: Antoine Tenart 
Reviewed-by: Alexander Duyck 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

lwt: Disable BH too in run_lwt_bpf()

2020-12-30T10:51:30+00:00

[ Upstream commit d9054a1ff585ba01029584ab730efc794603d68f ]

The per-cpu bpf_redirect_info is shared among all skb_do_redirect()
and BPF redirect helpers. Callers on RX path are all in BH context,
disabling preemption is not sufficient to prevent BH interruption.

In production, we observed strange packet drops because of the race
condition between LWT xmit and TC ingress, and we verified this issue
is fixed after we disable BH.

Although this bug was technically introduced from the beginning, that
is commit 3a0af8fd61f9 ("bpf: BPF for lightweight tunnel infrastructure"),
at that time call_rcu() had to be call_rcu_bh() to match the RCU context.
So this patch may not work well before RCU flavor consolidation has been
completed around v5.0.

Update the comments above the code too, as call_rcu() is now BH friendly.

Signed-off-by: Dongdong Wang 
Signed-off-by: Alexei Starovoitov 
Reviewed-by: Cong Wang 
Link: https://lore.kernel.org/bpf/20201205075946.497763-1-xiyou.wangcong@gmail.com
Signed-off-by: Sasha Levin

net: skbuff: ensure LSE is pullable before decrementing the MPLS ttl

2020-12-08T09:40:26+00:00

[ Upstream commit 13de4ed9e3a9ccbe54d05f7d5c773f69ecaf6c64 ]

skb_mpls_dec_ttl() reads the LSE without ensuring that it is contained in
the skb "linear" area. Fix this calling pskb_may_pull() before reading the
current ttl.

Found by code inspection.

Fixes: 2a2ea50870ba ("net: sched: add mpls manipulation actions to TC")
Reported-by: Marcelo Ricardo Leitner 
Signed-off-by: Davide Caratti 
Link: https://lore.kernel.org/r/53659f28be8bc336c113b5254dc637cc76bbae91.1606987074.git.dcaratti@redhat.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

sock: set sk_err to ee_errno on dequeue from errq

2020-12-08T09:40:23+00:00

[ Upstream commit 985f7337421a811cb354ca93882f943c8335a6f5 ]

When setting sk_err, set it to ee_errno, not ee_origin.

Commit f5f99309fa74 ("sock: do not set sk_err in
sock_dequeue_err_skb") disabled updating sk_err on errq dequeue,
which is correct for most error types (origins):

  -       sk->sk_err = err;

Commit 38b257938ac6 ("sock: reset sk_err when the error queue is
empty") reenabled the behavior for IMCP origins, which do require it:

  +       if (icmp_next)
  +               sk->sk_err = SKB_EXT_ERR(skb_next)->ee.ee_origin;

But read from ee_errno.

Fixes: 38b257938ac6 ("sock: reset sk_err when the error queue is empty")
Reported-by: Ayush Ranjan 
Signed-off-by: Willem de Bruijn 
Acked-by: Soheil Hassas Yeganeh 
Link: https://lore.kernel.org/r/20201126151220.2819322-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

devlink: Hold rtnl lock while reading netdev attributes

2020-12-08T09:40:23+00:00

[ Upstream commit b187c9b4178b87954dbc94e78a7094715794714f ]

A netdevice of a devlink port can be moved to different net namespace
than its parent devlink instance.
This scenario occurs when devlink reload is not used.

When netdevice is undergoing migration to net namespace, its ifindex
and name may change.

In such use case, devlink port query may read stale netdev attributes.

Fix it by reading them under rtnl lock.

Fixes: bfcd3a466172 ("Introduce devlink infrastructure")
Signed-off-by: Parav Pandit 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

bpf, sockmap: Avoid returning unneeded EAGAIN when redirecting to self

2020-11-24T12:29:19+00:00

[ Upstream commit 6fa9201a898983da731fca068bb4b5c941537588 ]

If a socket redirects to itself and it is under memory pressure it is
possible to get a socket stuck so that recv() returns EAGAIN and the
socket can not advance for some time. This happens because when
redirecting a skb to the same socket we received the skb on we first
check if it is OK to enqueue the skb on the receiving socket by checking
memory limits. But, if the skb is itself the object holding the memory
needed to enqueue the skb we will keep retrying from kernel side
and always fail with EAGAIN. Then userspace will get a recv() EAGAIN
error if there are no skbs in the psock ingress queue. This will continue
until either some skbs get kfree'd causing the memory pressure to
reduce far enough that we can enqueue the pending packet or the
socket is destroyed. In some cases its possible to get a socket
stuck for a noticeable amount of time if the socket is only receiving
skbs from sk_skb verdict programs. To reproduce I make the socket
memory limits ridiculously low so sockets are always under memory
pressure. More often though if under memory pressure it looks like
a spurious EAGAIN error on user space side causing userspace to retry
and typically enough has moved on the memory side that it works.

To fix skip memory checks and skb_orphan if receiving on the same
sock as already assigned.

For SK_PASS cases this is easy, its always the same socket so we
can just omit the orphan/set_owner pair.

For backlog cases we need to check skb->sk and decide if the orphan
and set_owner pair are needed.

Fixes: 51199405f9672 ("bpf: skb_verdict, support SK_PASS on RX BPF path")
Signed-off-by: John Fastabend
Signed-off-by: Daniel Borkmann
Reviewed-by: Jakub Sitnicki
Link: https://lore.kernel.org/bpf/160556572660.73229.12566203819812939627.stgit@john-XPS-13-9370
Signed-off-by: Sasha Levin