linux-stable.git/Documentation/networking, branch linux-5.4.y

xsk: Honor SO_BINDTODEVICE on bind

2023-07-27T06:37:23+00:00

[ Upstream commit f7306acec9aae9893d15e745c8791124d42ab10a ]

Initial creation of an AF_XDP socket requires CAP_NET_RAW capability. A
privileged process might create the socket and pass it to a non-privileged
process for later use. However, that process will be able to bind the socket
to any network interface. Even though it will not be able to receive any
traffic without modification of the BPF map, the situation is not ideal.

Sockets already have a mechanism that can be used to restrict what interface
they can be attached to. That is SO_BINDTODEVICE.

To change the SO_BINDTODEVICE binding the process will need CAP_NET_RAW.

Make xsk_bind() honor the SO_BINDTODEVICE in order to allow safer workflow
when non-privileged process is using AF_XDP.

The intended workflow is following:

  1. First process creates a bare socket with socket(AF_XDP, ...).
  2. First process loads the XSK program to the interface.
  3. First process adds the socket fd to a BPF map.
  4. First process ties socket fd to a particular interface using
     SO_BINDTODEVICE.
  5. First process sends socket fd to a second process.
  6. Second process allocates UMEM.
  7. Second process binds socket to the interface with bind(...).
  8. Second process sends/receives the traffic.

All the steps above are possible today if the first process is privileged
and the second one has sufficient RLIMIT_MEMLOCK and no capabilities.
However, the second process will be able to bind the socket to any interface
it wants on step 7 and send traffic from it. With the proposed change, the
second process will be able to bind the socket only to a specific interface
chosen by the first process at step 4.

Fixes: 965a99098443 ("xsk: add support for bind for Rx")
Signed-off-by: Ilya Maximets 
Signed-off-by: Daniel Borkmann 
Acked-by: Magnus Karlsson 
Acked-by: John Fastabend 
Acked-by: Jason Wang 
Link: https://lore.kernel.org/bpf/20230703175329.3259672-1-i.maximets@ovn.org
Signed-off-by: Sasha Levin

xsk: Improve documentation for AF_XDP

2023-07-27T06:37:23+00:00

[ Upstream commit e0e4f8e938c48b7c5377661fa3e4738901e6a19b ]

Added sections on all the bind flags, libbpf, all the setsockopts and
all the getsockopts. Also updated the document to reflect the latest
features and to correct some spelling errors.

v1 -> v2:
* Updated XDP program with latest BTF map format
* Added one more FAQ entry
* Some minor edits and corrections

v2 -> v3:
* Simplified XDP_SHARED_UMEM example XDP program

Signed-off-by: Magnus Karlsson 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/1571648224-16889-1-git-send-email-magnus.karlsson@intel.com
Stable-dep-of: f7306acec9aa ("xsk: Honor SO_BINDTODEVICE on bind")
Signed-off-by: Sasha Levin

Remove DECnet support from kernel

2023-06-21T13:44:10+00:00

commit 1202cdd665315c525b5237e96e0bedc76d7e754f upstream.

DECnet is an obsolete network protocol that receives more attention
from kernel janitors than users. It belongs in computer protocol
history museum not in Linux kernel.

It has been "Orphaned" in kernel since 2010. The iproute2 support
for DECnet was dropped in 5.0 release. The documentation link on
Sourceforge says it is abandoned there as well.

Leave the UAPI alone to keep userspace programs compiling.
This means that there is still an empty neighbour table
for AF_DECNET.

The table of /proc/sys/net entries was updated to match
current directories and reformatted to be alphabetical.

Signed-off-by: Stephen Hemminger 
Acked-by: David Ahern 
Acked-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

Documentation: fix sctp_wmem in ip-sysctl.rst

2022-08-03T09:59:40+00:00

[ Upstream commit aa709da0e032cee7c202047ecd75f437bb0126ed ]

Since commit 1033990ac5b2 ("sctp: implement memory accounting on tx path"),
SCTP has supported memory accounting on tx path where 'sctp_wmem' is used
by sk_wmem_schedule(). So we should fix the description for this option in
ip-sysctl.rst accordingly.

v1->v2:
  - Improve the description as Marcelo suggested.

Fixes: 1033990ac5b2 ("sctp: implement memory accounting on tx path")
Signed-off-by: Xin Long 
Acked-by: Marcelo Ricardo Leitner 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

ipv4: Fix data-races around sysctl_ip_dynaddr.

2022-07-21T18:59:22+00:00

[ Upstream commit e49e4aff7ec19b2d0d0957ee30e93dade57dab9e ]

While reading sysctl_ip_dynaddr, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

cipso: Fix data-races around sysctl.

2022-07-21T18:59:20+00:00

[ Upstream commit dd44f04b9214adb68ef5684ae87a81ba03632250 ]

While reading cipso sysctl variables, they can be changed concurrently.
So, we need to add READ_ONCE() to avoid data-races.

Fixes: 446fda4f2682 ("[NetLabel]: CIPSOv4 engine")
Signed-off-by: Kuniyuki Iwashima 
Acked-by: Paul Moore 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

bonding: fix ad_actor_system option setting to default

2021-12-29T11:23:35+00:00

[ Upstream commit 1c15b05baea71a5ff98235783e3e4ad227760876 ]

When 802.3ad bond mode is configured the ad_actor_system option is set to
"00:00:00:00:00:00". But when trying to set the all-zeroes MAC as actors'
system address it was failing with EINVAL.

An all-zeroes ethernet address is valid, only multicast addresses are not
valid values.

Fixes: 171a42c38c6e ("bonding: add netlink support for sys prio, actor sys mac, and port key")
Signed-off-by: Fernando Fernandez Mancera 
Acked-by: Jay Vosburgh 
Link: https://lore.kernel.org/r/20211221111345.2462-1-ffmancera@riseup.net
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

netfilter: ipvs: Fix reuse connection if RS weight is 0

2021-12-01T08:23:31+00:00

[ Upstream commit c95c07836fa4c1767ed11d8eca0769c652760e32 ]

We are changing expire_nodest_conn to work even for reused connections when
conn_reuse_mode=0, just as what was done with commit dc7b3eb900aa ("ipvs:
Fix reuse connection if real server is dead").

For controlled and persistent connections, the new connection will get the
needed real server depending on the rules in ip_vs_check_template().

Fixes: d752c3645717 ("ipvs: allow rescheduling of new connections when port reuse is detected")
Co-developed-by: Chuanqi Liu 
Signed-off-by: Chuanqi Liu 
Signed-off-by: yangxingwu 
Acked-by: Simon Horman 
Acked-by: Julian Anastasov 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

can: j1939: swap addr and pgn in the send example

2020-11-18T18:20:19+00:00

[ Upstream commit ea780d39b1888ed5afc243c29b23d9bdb3828c7a ]

The address was wrongly assigned to the PGN field and vice versa.

Signed-off-by: Yegor Yefremov 
Link: https://lore.kernel.org/r/20201022083708.8755-1-yegorslists@googlemail.com
Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
Signed-off-by: Marc Kleine-Budde 
Signed-off-by: Sasha Levin

icmp: randomize the global rate limiter

2020-10-29T08:57:27+00:00

[ Upstream commit b38e7819cae946e2edf869e604af1e65a5d241c5 ]

Keyu Man reported that the ICMP rate limiter could be used
by attackers to get useful signal. Details will be provided
in an upcoming academic publication.

Our solution is to add some noise, so that the attackers
no longer can get help from the predictable token bucket limiter.

Fixes: 4cdf507d5452 ("icmp: add a global rate limitation")
Signed-off-by: Eric Dumazet 
Reported-by: Keyu Man 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman